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1

USE OF BIOASSAY-DIRECTED CHEMICAL ANALYSIS FOR IDENTIFYING MUTAGENIC COMPOUNDS IN URBAN AIR AND COMBUSTION EMISSIONS  

EPA Science Inventory

Bioassay-directed chemical analysis fractionation has been used for 30 years to identify mutagenic classes of compounds in complex mixtures. Most studies have used the Salmonella (Ames) mutagenicity assay, and we have recently applied this methodology to two standard reference sa...

2

Devices for collecting chemical compounds  

DOEpatents

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.

Scott, Jill R; Groenewold, Gary S

2013-12-24

3

Public chemical compound databases.  

PubMed

The internet has rapidly become the first port of call for all information searches. The increasing array of chemistry-related resources that are now available provides chemists with a direct path to the information that was previously accessed via library services and was limited by commercial and costly resources. The diversity of the information that can be accessed online is expanding at a dramatic rate, and the support for publicly available resources offers significant opportunities in terms of the benefits to science and society. While the data online do not generally meet the quality standards of manually curated sources, there are efforts underway to gather scientists together and 'crowdsource' an improvement in the quality of the available data. This review discusses the types of public compound databases that are available online and provides a series of examples. Focus is also given to the benefits and disruptions associated with the increased availability of such data and the integration of technologies to data mine this information. PMID:18428094

Williams, Anthony J

2008-05-01

4

Chemistry & Biology Synthetic Lethal Screening Identifies Compounds  

E-print Network

Chemistry & Biology Article Synthetic Lethal Screening Identifies Compounds Activating IronDepartment of Biological Sciences 2Department of Chemistry Columbia University, Fairchild Center, MC2406, 1212 Amsterdam Avenue, New York, NY 10027, USA *Correspondence: stockwell@biology.columbia.edu DOI 10

Stockwell, Brent R.

5

Indexing molecules with chemical graph identifiers.  

PubMed

Fast and robust algorithms for indexing molecules have been historically considered strategic tools for the management and storage of large chemical libraries. This work introduces a modified and further extended version of the molecular equivalence number naming adaptation of the Morgan algorithm (J Chem Inf Comput Sci 2001, 41, 181-185) for the generation of a chemical graph identifier (CGI). This new version corrects for the collisions recognized in the original adaptation and includes the ability to deal with graph canonicalization, ensembles (salts), and isomerism (tautomerism, regioisomerism, optical isomerism, and geometrical isomerism) in a flexible manner. Validation of the current CGI implementation was performed on the open NCI database and the drug-like subset of the ZINC database containing 260,071 and 5,348,089 structures, respectively. The results were compared with those obtained with some of the most widely used indexing codes, such as the CACTVS hash code and the new InChIKey. The analyses emphasize the fact that compound management activities, like duplicate analysis of chemical libraries, are sensitive to the exact definition of compound uniqueness and thus still depend, to a minor extent, on the type and flexibility of the molecular index being used. PMID:21647928

Gregori-Puigjané, Elisabet; Garriga-Sust, Rut; Mestres, Jordi

2011-09-01

6

Identifying chemicals that are planetary boundary threats.  

PubMed

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

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

2014-10-01

7

Complex Compound Chemical Heat Pumps  

E-print Network

Complex-compound solid-vapor fluid pairs can be used in heat of reaction heat pumps for temperature amplifier (TA) as well as heat amplifier (HA) cycle configurations. This report describes the conceptual hardware design for complex compound...

Rockenfeller, U.; Langeliers, J.; Horn, G.

8

Assimilating chemical compound with a regional chemical model  

NASA Astrophysics Data System (ADS)

To constrain the sink and source of the chemical compounds at surface during model simulation, chemical compound assimilation with Local Ensemble Transform Kalman Filter has been implemented for the WRFChemT model. The WRFChemT model has the chemical components coupled with the regional meteorological model with specified surface fluxes of the chemical compounds. Previous related studies on chemical assimilation have been focusing on the impact on the global atmospheric models (Kang et al. 2010 and Liu et al. 2010). In this study, we investigate the regional impact of the chemical compounds. Different from the applications of EnKF to weather prediction, the interactions between meteorological variables and surface emission of the chemical compounds are indirect and bridged through the tracer variables. How to construct the coupled atmospheric-chemical multi-variate error covariance based on the ensemble becomes the challenge of this new assimilation system. In this work, we perform OSSE experiments to evaluate the performance of the new assimilation system and also to investigate the strategies for assimilating the chemical compounds with LETKF. Corrections for surface flux can be obtained from adequately using observations of meteorology and chemical compounds with the ensemble-based multivariable covariance. Results suggest that meteorological dynamics plays a crucial role in adjusting the total mass of the chemical compounds, which in turns affect the retrieval of the surface emission.

Yang, S.; Liang, M.; Tseng, Y.

2011-12-01

9

Identifying interactions between chemical entities in biomedical text.  

PubMed

Interactions between chemical compounds described in biomedical text can be of great importance to drug discovery and design, as well as pharmacovigilance. We developed a novel system, \\"Identifying Interactions between Chemical Entities\\" (IICE), to identify chemical interactions described in text. Kernel-based Support Vector Machines first identify the interactions and then an ensemble classifier validates and classifies the type of each interaction. This relation extraction module was evaluated with the corpus released for the DDI Extraction task of SemEval 2013, obtaining results comparable to state-of-the-art methods for this type of task. We integrated this module with our chemical named entity recognition module and made the whole system available as a web tool at www.lasige.di.fc.ul.pt/webtools/iice. PMID:25339081

Lamurias, Andre; Ferreira, João D; Couto, Francisco M

2014-01-01

10

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...

11

Microfluidic in vivo screen identifies compounds enhancing neuronal  

E-print Network

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 ...

Haggarty, Stephen

12

Identification of chemical compounds from the leaves of Leea indica.  

PubMed

Twenty-three known chemical compounds were identified in the leaves of Leea indica (Burm. f.) Merr. (Leeaceae) by GC-MS analysis, spectroscopic techniques and co-TLC with authentic samples. The identified compounds include eleven hydrocarbons, phthalic acid, palmitic acid, 1-eicosanol, solanesol, farnesol, three phthalic acid esters, gallic acid, lupeol, beta-sitosterol and ursolic acid. Gallic acid was isolated as n-butyl gallate and identified by co-TLC. This seems to be the first report of the presence of gallic acid in the leaves of L. indica. PMID:18515230

Srinivasan, Govindarajapuram Varadarajan; Ranjith, Choorikkat; Vijayan, Kochukaratu Krishnan

2008-06-01

13

Lifetime of a Chemically Bound Helium Compound  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

14

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

SciTech Connect

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.

Hauschild, Veronique [U.S. Army Public Health Command] [U.S. Army Public Health Command; Watson, Annetta Paule [ORNL] [ORNL

2013-01-01

15

A staining protocol for identifying secondary compounds in Myrtaceae1  

PubMed Central

• Premise of the study: Here we propose a staining protocol using toluidine blue (TBO) and ruthenium red to reliably identify secondary compounds in the leaves of some species of Myrtaceae. • Methods and Results: Leaves of 10 species representing 10 different genera of Myrtaceae were processed and stained using five different combinations of ruthenium red and TBO. Optimal staining conditions were determined as 1 min of ruthenium red (0.05% aqueous) and 45 s of TBO (0.1% aqueous). Secondary compounds clearly identified under this treatment include mucilage in the mesophyll, polyphenols in the cuticle, lignin in fibers and xylem, tannins and carboxylated polysaccharides in the epidermis, and pectic substances in the primary cell walls. • Conclusions: Potential applications of this protocol include systematic, phytochemical, and ecological investigations in Myrtaceae. It might be applicable to other plant families rich in secondary compounds and could be used as a preliminary screening method for extraction of these elements. PMID:25309840

Retamales, Hernan A.; Scharaschkin, Tanya

2014-01-01

16

Spectral data bases for chemical compound identification  

Microsoft Academic Search

The status of the large data bases for identifying unknown compounds by the use of X-ray diffraction, infrared spectrometry, Raman spectrometry and mass spectrometry is discussed. The paper reviews various spectra-encoding methods and library search techniques. The efficiency of identification of components in mixtures is evaluated from the point of view of information theory and miscellaneous methods toi separate the

Jaroslav Fiala

1984-01-01

17

A Quantitative High Throughput Assay for Identifying Gametocytocidal Compounds  

PubMed Central

Current antimalarial drug treatment does not effectively kill mature Plasmodium falciparum gametocytes, the parasite stage responsible for malaria transmission from human to human via a mosquito. Consequently, following standard therapy malaria can still be transmitted for over a week after the clearance of asexual parasites. A new generation of malaria drugs with gametocytocidal properties, or a gametocytocidal drug that could be used in combinational therapy with currently available antimalarials, is needed to control the spread of the disease and facilitate eradication efforts. We have developed a 1,536-well gametocyte viability assay for the high throughput screening of large compound collections to identify novel compounds with gametocytocidal activity. The signal-to-basal ratio and Z?-factor for this assay were 3.2-fold and 0.68, respectively. The IC50 value of epoxomicin, the positive control compound, was 1.42 ± 0.09 nM that is comparable to previously reported values. This miniaturized assay significantly reduces the number of gametocytes required for the alamarBlue viability assay, and enables high throughput screening for lead discovery efforts. Additionally, the screen does not require a specialized parasite line, gametocytes from any strain, including field isolates, can be tested. A pilot screen utilizing the commercially available LOPAC library, consisting of 1,280 known compounds, revealed two selective gametocytocidal compounds having 54 and 7.8-fold gametocytocidal selectivity in comparison to their cell cytotoxicity effect against the mammalian SH-SY5Y cell line. PMID:23454872

Tanaka, Takeshi Q.; Dehdashti, Seameen J.; Nguyen, Dac-Trung; McKew, John C.; Zheng, Wei; Williamson, Kim C.

2013-01-01

18

Antiapicoplast and Gametocytocidal Screening To Identify the Mechanisms of Action of Compounds within the Malaria Box  

PubMed Central

Malaria remains a significant infectious disease that causes millions of clinical cases and >800,000 deaths per year. The Malaria Box is a collection of 400 commercially available chemical entities that have antimalarial activity. The collection contains 200 drug-like compounds, based on their oral absorption and the presence of known toxicophores, and 200 probe-like compounds, which are intended to represent a broad structural diversity. These compounds have confirmed activities against the asexual intraerythrocytic stages of Plasmodium falciparum and low cytotoxicities, but their mechanisms of action and their activities in other stages of the parasite's life cycle remain to be determined. The apicoplast is considered to be a promising source of malaria-specific targets, and its main function during intraerythrocytic stages is to provide the isoprenoid precursor isopentenyl diphosphate, which can be used for phenotype-based screens to identify compounds targeting this organelle. We screened 400 compounds from the Malaria Box using apicoplast-targeting phenotypic assays to identify their potential mechanisms of action. We identified one compound that specifically targeted the apicoplast. Further analyses indicated that the molecular target of this compound may differ from those of the current antiapicoplast drugs, such as fosmidomycin. Moreover, in our efforts to elucidate the mechanisms of action of compounds from the Malaria Box, we evaluated their activities against other stages of the life cycle of the parasite. Gametocytes are the transmission stage of the malaria parasite and are recognized as a priority target in efforts to eradicate malaria. We identified 12 compounds that were active against gametocytes with 50% inhibitory concentration values of <1 ?M. PMID:24247137

Bowman, Jessica D.; Merino, Emilio F.; Brooks, Carrie F.; Striepen, Boris; Carlier, Paul R.

2014-01-01

19

Antiapicoplast and gametocytocidal screening to identify the mechanisms of action of compounds within the malaria box.  

PubMed

Malaria remains a significant infectious disease that causes millions of clinical cases and >800,000 deaths per year. The Malaria Box is a collection of 400 commercially available chemical entities that have antimalarial activity. The collection contains 200 drug-like compounds, based on their oral absorption and the presence of known toxicophores, and 200 probe-like compounds, which are intended to represent a broad structural diversity. These compounds have confirmed activities against the asexual intraerythrocytic stages of Plasmodium falciparum and low cytotoxicities, but their mechanisms of action and their activities in other stages of the parasite's life cycle remain to be determined. The apicoplast is considered to be a promising source of malaria-specific targets, and its main function during intraerythrocytic stages is to provide the isoprenoid precursor isopentenyl diphosphate, which can be used for phenotype-based screens to identify compounds targeting this organelle. We screened 400 compounds from the Malaria Box using apicoplast-targeting phenotypic assays to identify their potential mechanisms of action. We identified one compound that specifically targeted the apicoplast. Further analyses indicated that the molecular target of this compound may differ from those of the current antiapicoplast drugs, such as fosmidomycin. Moreover, in our efforts to elucidate the mechanisms of action of compounds from the Malaria Box, we evaluated their activities against other stages of the life cycle of the parasite. Gametocytes are the transmission stage of the malaria parasite and are recognized as a priority target in efforts to eradicate malaria. We identified 12 compounds that were active against gametocytes with 50% inhibitory concentration values of <1 ?M. PMID:24247137

Bowman, Jessica D; Merino, Emilio F; Brooks, Carrie F; Striepen, Boris; Carlier, Paul R; Cassera, Maria B

2014-01-01

20

Using Properties to Identify Ionic and Molecular Compounds  

NSDL National Science Digital Library

An inquiry activity for students to test physical properties of several compounds to analyze data and determine if the compound is ionic or covalent. This is ideal for an introduction to ionic and molecular compound nomenclature.

Tamara Ellsworth, Parkers Prairie High School, Parkers Prairie, MN, based on a lab for pre-ap chemistry at the westlake high school website.

21

Device for collecting chemical compounds and related methods  

DOEpatents

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.

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

2013-01-01

22

Identifying organic nitrogen compounds in Rocky Mountain National Park aerosols  

NASA Astrophysics Data System (ADS)

Nitrogen deposition is an important issue in Rocky Mountain National Park (RMNP). While inorganic nitrogen contributions to the ecosystems in this area have been studied, the sources of organic nitrogen are still largely unknown. To better understand the potential sources of organic nitrogen, filter samples were collected and analyzed for organic nitrogen species. Samples were collected in RMNP using a Thermo Fisher Scientific TSP (total suspended particulate) high-volume sampler with a PM2.5 impactor plate from April - November of 2008. The samples presented the opportunity to compare two different methods for identification of individual organic nitrogen species. The first type of analysis was performed with a comprehensive two dimensional gas chromatography (GCxGC) system using a nitrogen chemiluminescence detector (NCD). The filter samples were spiked with propanil in dichloromethane to use as an internal standard and were then extracted in water followed by solid phase extraction. The GCxGC system was comprised of a volatility based separation (DB5 column) followed by a polarity based separation (RXI-17 column). A NCD was used to specifically detect nitrogen compounds and remove the complex background matrix. Individual standards were used to identify peaks by comparing retention times. This method has the added benefit of an equimolar response for nitrogen so only a single calibration is needed for all species. In the second analysis, a portion of the same filter samples were extracted in DI water and analyzed with liquid chromatography coupled with mass spectroscopy (LC/MS). The separation was performed using a C18 column and a water-methanol gradient elution. Electrospray ionization into a time of flight mass spectrometer was used for detection. High accuracy mass measurement allowed unambiguous assignments of elemental composition of resulting ions. Positive and negative polarities were used since amines tend to show up in positive mode and nitrates in negative. The differences in the number of species and what species are identified between these two methods are important for planning future analyses of organic nitrogen compounds. In addition, these data provide new insight into the potential source of organic nitrogen in RMNP. Using the GCxGC method, 39 organic nitrogen species were detected and 20 were identified. Identified species include several types of amines and phenols. The LC/MS method identified several types of cresols, amines, and nitrates.

Beem, K. B.; Desyaterik, Y.; Ozel, M. Z.; Hamilton, J. F.; Collett, J. L.

2010-12-01

23

APPLICATION OF AN ANALYSIS PROTOCOL TO IDENTIFY ORGANIC COMPOUNDS NOT IDENTIFIED BY SPECTRUM MATCHING. PART 1: TEXT  

EPA Science Inventory

Industrial wastewater survey samples were analyzed for organic compounds not identified by spectrum matching. Analysis of the samples proceeded from an initial packed column GC/MS analysis for Priority Pollutants, through computerized spectrum matching for other compounds, to the...

24

Predicting Biological Functions of Compounds Based on Chemical-Chemical Interactions  

PubMed Central

Given a compound, how can we effectively predict its biological function? It is a fundamentally important problem because the information thus obtained may benefit the understanding of many basic biological processes and provide useful clues for drug design. In this study, based on the information of chemical-chemical interactions, a novel method was developed that can be used to identify which of the following eleven metabolic pathway classes a query compound may be involved with: (1) Carbohydrate Metabolism, (2) Energy Metabolism, (3) Lipid Metabolism, (4) Nucleotide Metabolism, (5) Amino Acid Metabolism, (6) Metabolism of Other Amino Acids, (7) Glycan Biosynthesis and Metabolism, (8) Metabolism of Cofactors and Vitamins, (9) Metabolism of Terpenoids and Polyketides, (10) Biosynthesis of Other Secondary Metabolites, (11) Xenobiotics Biodegradation and Metabolism. It was observed that the overall success rate obtained by the method via the 5-fold cross-validation test on a benchmark dataset consisting of 3,137 compounds was 77.97%, which is much higher than 10.45%, the corresponding success rate obtained by the random guesses. Besides, to deal with the situation that some compounds may be involved with more than one metabolic pathway class, the method presented here is featured by the capacity able to provide a series of potential metabolic pathway classes ranked according to the descending order of their likelihood for each of the query compounds concerned. Furthermore, our method was also applied to predict 5,549 compounds whose metabolic pathway classes are unknown. Interestingly, the results thus obtained are quite consistent with the deductions from the reports by other investigators. It is anticipated that, with the continuous increase of the chemical-chemical interaction data, the current method will be further enhanced in its power and accuracy, so as to become a useful complementary vehicle in annotating uncharacterized compounds for their biological functions. PMID:22220213

Huang, Tao; Cai, Yu-Dong; Chou, Kuo-Chen

2011-01-01

25

InChI - the worldwide chemical structure identifier standard  

PubMed Central

Since its public introduction in 2005 the IUPAC InChI chemical structure identifier standard has become the international, worldwide standard for defined chemical structures. This article will describe the extensive use and dissemination of the InChI and InChIKey structure representations by and for the world-wide chemistry community, the chemical information community, and major publishers and disseminators of chemical and related scientific offerings in manuscripts and databases. PMID:23343401

2013-01-01

26

A Yeast Chemical Genetic Screen Identifies Inhibitors of Human Telomerase  

PubMed Central

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

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

2013-01-01

27

Synchrotron radiation identified human chemical fingerprints a novel forensic approach  

E-print Network

a forensic analysis of the fingerprint chemistry, or to identify the latent prints of pre-pubescent childrenSynchrotron radiation identified human chemical fingerprints ­ a novel forensic approach T with the goal of developing an advanced forensic technique to identify complicated partial latent prints

28

Zebrafish screen identifies novel compound with selective toxicity against leukemia  

PubMed Central

To detect targeted antileukemia agents we have designed a novel, high-content in vivo screen using genetically engineered, T-cell reporting zebrafish. We exploited the developmental similarities between normal and malignant T lymphoblasts to screen a small molecule library for activity against immature T cells with a simple visual readout in zebrafish larvae. After screening 26 400 molecules, we identified Lenaldekar (LDK), a compound that eliminates immature T cells in developing zebrafish without affecting the cell cycle in other cell types. LDK is well tolerated in vertebrates and induces long-term remission in adult zebrafish with cMYC-induced T-cell acute lymphoblastic leukemia (T-ALL). LDK causes dephosphorylation of members of the PI3 kinase/AKT/mTOR pathway and delays sensitive cells in late mitosis. Among human cancers, LDK selectively affects survival of hematopoietic malignancy lines and primary leukemias, including therapy-refractory B-ALL and chronic myelogenous leukemia samples, and inhibits growth of human T-ALL xenografts. This work demonstrates the utility of our method using zebrafish for antineoplastic candidate drug identification and suggests a new approach for targeted leukemia therapy. Although our efforts focused on leukemia therapy, this screening approach has broad implications as it can be translated to other cancer types involving malignant degeneration of developmentally arrested cells. PMID:22490804

Ridges, Suzanne; Heaton, Will L.; Joshi, Deepa; Choi, Henry; Eiring, Anna; Batchelor, Lance; Choudhry, Priya; Manos, Elizabeth J.; Sofla, Hossein; Sanati, Ali; Welborn, Seth; Agarwal, Archana; Spangrude, Gerald J.; Miles, Rodney R.; Cox, James E.; Frazer, J. Kimble; Deininger, Michael; Balan, Kaveri; Sigman, Matthew; Muschen, Markus; Perova, Tatiana; Johnson, Radia; Montpellier, Bertrand; Guidos, Cynthia J.; Jones, David A.

2012-01-01

29

Expanding the medicinally relevant chemical space with compound libraries.  

PubMed

Analysis of marketed drugs and commercial vendor libraries used in high-throughput screening suggests that the medicinally relevant chemical space may be expanded to unexplored regions. Novel regions of the chemical space can be conveniently explored with structurally unique molecules with increased complexity and balanced physicochemical properties. As a case study, we discuss the chemoinformatic profile of natural products in the Traditional Chinese Medicine (TCM) database and a large collection assembled from 30 small-molecule combinatorial libraries with emphasis on assessing molecular complexity. The herein surveyed combinatorial libraries have been successfully used over the past 20 years to identify novel bioactive compounds across different therapeutic areas. Combinatorial libraries and natural products are suitable sources to expand the traditional relevant medicinal chemistry space. PMID:22515962

López-Vallejo, Fabian; Giulianotti, Marc A; Houghten, Richard A; Medina-Franco, José L

2012-07-01

30

Chemical Genetics: Elucidating Biological Systems with Small-Molecule Compounds  

E-print Network

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 processes in a manner analogous to the mutagenesis strategies at the core of classical genetics. Screening

Nghiem, Paul

31

Species-dependent variation in algal sensitivity to chemical compounds.  

PubMed

Nineteen miscellaneous chemical compounds were tested on thirteen freshwater algal species grown in 250-microliter liquid cultures on plastic microtitration plates. It was demonstrated that the species-dependent variation in algal sensitivity (EC100) may reach over three orders of magnitude, the degree of variation depending on the chemical tested. No generally sensitive or generally insensitive species could be identified. An effort was made to quantify the predictive value of algal test batteries, at a given confidence level with respect to chemicals. The predictive value of small test batteries was low. Although it did increase with size it took the presence of more than nine members in the test batteries to improve the value to 0.1. This means that a nine-membered test battery might underestimate the sensitivity of the most susceptible algae by a factor of 0.1. A predictive value of 0.01 requires a three-membered test battery when accounting for 95% of the chemicals and a five-membered battery at the 99% confidence level. Implications for toxicity test strategies are discussed and it is suggested that algal test batteries, using simple test techniques, replace single unialgal cultures in routine work. PMID:6479081

Blanck, H; Wallin, G; Wängberg, S A

1984-08-01

32

Chemical bonding in titanium-metalloid compounds  

Microsoft Academic Search

First-principles molecular-orbital calculations for titanium-metalloid compounds TiB, TiB2, TiC, Ti2N, TiN, TiO, TiO2, TiSi, TiSi2, TiP, TiS, and TiS2 have been made by the use of discrete-variational Xalpha method with model clusters composed of about 100 atoms. In order to compare the covalent bonding quantitatively among these compounds with different crystal structures, we used covalent bond density in which both

Masataka Mizuno; Isao Tanaka; Hirohiko Adachi

1999-01-01

33

Helping Students Distinguish between Mixtures and Chemical Compounds.  

ERIC Educational Resources Information Center

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)

Papageorgiou, George

2002-01-01

34

Chemical compounds of the foraging recruitment pheromone in bumblebees  

NASA Astrophysics Data System (ADS)

When the frenzied and irregular food-recruitment dances of bumblebees were first discovered, it was thought that they might represent an evolutionary prototype to the honeybee waggle dance. It later emerged that the primary function of the bumblebee dance was the distribution of an alerting pheromone. Here, we identify the chemical compounds of the bumblebee recruitment pheromone and their behaviour effects. The presence of two monoterpenes and one sesquiterpene (eucalyptol, ocimene and farnesol) in the nest airspace and in the tergal glands increases strongly during foraging. Of these, eucalyptol has the strongest recruitment effect when a bee nest is experimentally exposed to it. Since honeybees use terpenes for marking food sources rather than recruiting foragers inside the nest, this suggests independent evolutionary roots of food recruitment in these two groups of bees.

Granero, Angeles Mena; Sanz, José M. Guerra; Gonzalez, Francisco J. Egea; Vidal, José L. Martinez; Dornhaus, Anna; Ghani, Junaid; Serrano, Ana Roldán; Chittka, Lars

2005-08-01

35

A chemical screen identifies small molecules that regulate hepcidin expression.  

PubMed

Hepcidin, a peptide hormone produced in the liver, decreases intestinal iron absorption and macrophage iron release via effects on ferroportin. Bone morphogenic protein and Stat3 signaling regulate Hepcidin's transcription. Hepcidin is a potential drug target for patients with iron overload syndromes because its levels are inappropriately low in these individuals. To generate a tool for identifying small molecules that modulate Hepcidin expression, we stably transfected human hepatocytes (HepG2) cells with a reporter construct containing 2.7kb of the human Hepcidin promoter upstream of a firefly reporter gene. We used high throughput methods to screen 10,169 chemicals in duplicate for their effect on Hepcidin expression and cell viability. Regulators were identified as chemicals that caused a change >3 standard deviations above or >1 standard deviation below the mean of the other chemicals (z-score >3 or <1), while not adversely affecting cell viability, quantified by fluorescence assay. Following validation assays, we identified 16 chemicals in a broad range of functional classes that promote Hepcidin expression. All of the chemicals identified increased expression of bone morphogenic protein-dependent and/or Stat3-dependent genes, however none of them strongly increased phosphorylation of Smad1,5,8 or Stat3. PMID:24998898

Gaun, Vera; Patchen, Bonnie; Volovetz, Josephine; Zhen, Aileen W; Andreev, Aleksandr; Pollastri, Michael P; Fraenkel, Paula G

2014-12-01

36

Chemical Defenses: From Compounds to Communities  

Microsoft Academic Search

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 mecha- nisms of action, much less is known about ecological func- tions. The way in

VALERIE J. PAUL; KAREN E. ARTHUR; RAPHAEL RITSON-WILLIAMS; CLIFF ROSS; KOTY SHARP

37

LIGAND: Database of Chemical Compounds and Reactions in Biological Pathways  

NSDL National Science Digital Library

The Institute for Chemical Research at Kyoto University provides this frequently updated and well-documented database of enzyme reactions. With more than 9,300 entries, the LIGAND Chemical Database includes over 3,700 entries for enzymes (the Enzyme Reaction Database) and 5,600 entries for compounds (Chemical Compound Database). The database is searchable by keyword using DBGET (which supports numerous other databases and gene catalogs as well) and is accompanied by clear instructions. The LIGAND database, updated weekly, may be downloaded via anonymous FTP.

38

Antifungal Chemical Compounds Identified Using a C. elegans Pathogenicity Assay  

E-print Network

of the main obstacles in current antifungal discovery. We show that Candida albicans, as well as other Candida of the main obstacles in current antifungal discovery. Here, we show that Candida albicans, as well as other. elegans intestinal track. Importantly, key components of Candida pathogenesis in mammals, such as filament

Ausubel, Frederick M.

39

Chemical reactions of organic compounds on clay surfaces.  

PubMed Central

Chemical reactions of organic compounds including pesticides at the interlayer and exterior surfaces of clay minerals and with soil organic matter are reviewed. Representative reactions under moderate conditions possibly occurring in natural soils are described. Attempts have been made to clarify the importance of the chemical nature of molecules, their structures and their functional groups, and the Brönsted or Lewis acidity of clay minerals. PMID:2533556

Soma, Y; Soma, M

1989-01-01

40

STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS  

PubMed Central

Experiments with guinea pigs are described which show that under special experimental conditions the intraperitoneal injection of conjugates made with homologous erythrocyte stromata leads to typical skin sensitization of the contact type towards the respective simple chemicals, namely picryl chloride or 2,4-dinitrofluorobenzene. Therefore such sensitivity can be brought about not only by low molecular chemical compounds but by a material which must be regarded as a typical antigen. PMID:19871087

Landsteiner, K.; Chase, M. W.

1941-01-01

41

International chemical identifier for reactions (RInChI)  

PubMed Central

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

2013-01-01

42

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

43

Compound prioritization methods increase rates of chemical probe discovery in model organisms  

PubMed Central

SUMMARY Pre-selection of compounds that are more likely to induce a phenotype can increase the efficiency and reduce the costs for model organism screening. To identify such molecules, we screened ~81,000 compounds in S. cerevisiae and identified ~7,500 that inhibit cell growth. Screening these growth-inhibitory molecules across a diverse panel of model organisms resulted in an increased phenotypic hit-rate. This data was used to build a model to predict compounds that inhibit yeast growth. Empirical and in silico application of the model enriched the discovery of bioactive compounds in diverse model organisms. To demonstrate the potential of these molecules as lead chemical probes we used chemogenomic profiling in yeast and identified specific inhibitors of lanosterol synthase and of stearoyl-CoA 9-desaturase. As community resources, the ~7,500 growth-inhibitory molecules has been made commercially available and the computational model and filter used are provided. PMID:22035796

Wallace, Iain M; Urbanus, Malene L; Luciani, Genna M; Burns, Andrew R; Han, Mitchell KL; Wang, Hao; Arora, Kriti; Heisler, Lawrence E; Proctor, Michael; St. Onge, Robert P; Roemer, Terry; Roy, Peter J; Cummins, Carolyn L; Bader, Gary D; Nislow, Corey; Giaever, Guri

2011-01-01

44

Neuron-Semiconductor Chip with Chemical Synapse between Identified Neurons  

NASA Astrophysics Data System (ADS)

Noninvasive electrical stimulation and recording of neuronal networks from semiconductor chips is a prerequisite for the development of neuroelectronic devices. In a proof-of-principle experiment, we implemented the fundamental element of such future hybrids by joining a silicon chip with an excitatory chemical synapse between a pair of identified neurons from the pond snail. We stimulated the presynaptic cell (VD4) with a chip capacitor and recorded the activity of the postsynaptic cell (LPeD1) with a transistor. We enhanced the strength of the soma-soma synapse by repetitive capacitor stimulation, establishing a neuronal memory on the silicon chip.

Kaul, R. Alexander; Syed, Naweed I.; Fromherz, Peter

2004-01-01

45

Chemicals from coal. Utilization of coal-derived phenolic compounds  

SciTech Connect

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.

Song, C.; Schobert, H.H.

1999-07-01

46

Semantic Similarity for Automatic Classification of Chemical Compounds  

PubMed Central

With the increasing amount of data made available in the chemical field, there is a strong need for systems capable of comparing and classifying chemical compounds in an efficient and effective way. The best approaches existing today are based on the structure-activity relationship premise, which states that biological activity of a molecule is strongly related to its structural or physicochemical properties. This work presents a novel approach to the automatic classification of chemical compounds by integrating semantic similarity with existing structural comparison methods. Our approach was assessed based on the Matthews Correlation Coefficient for the prediction, and achieved values of 0.810 when used as a prediction of blood-brain barrier permeability, 0.694 for P-glycoprotein substrate, and 0.673 for estrogen receptor binding activity. These results expose a significant improvement over the currently existing methods, whose best performances were 0.628, 0.591, and 0.647 respectively. It was demonstrated that the integration of semantic similarity is a feasible and effective way to improve existing chemical compound classification systems. Among other possible uses, this tool helps the study of the evolution of metabolic pathways, the study of the correlation of metabolic networks with properties of those networks, or the improvement of ontologies that represent chemical information. PMID:20885779

Ferreira, Joao D.; Couto, Francisco M.

2010-01-01

47

Ecotoxicological and chemical evaluation of phenolic compounds in industrial effluents.  

PubMed

The aim of this paper was to evaluate the ecotoxicological response of industrial effluents containing phenolic compounds. All complex effluents collected from a chemical plant and then after both a chemical-physical and biological treatment were characterised with chemical analysis, biodegradability tests and four ecotoxicological tests (Daphnia magna, Artemia salina, Brachionus plicatilis and Vibriofisheri with Microtox). The evaluation of the chemical and ecotoxicological data was useful for predicting the effect of the raw effluent on the treatment plant and the impact of the final treated effluent on the receiving water. Besides the toxicity of the effluent from the chemical plants, the acute toxicity of its main components was also determined. The results of the tests and toxicity data from literature were transformed in Toxic Units (TUs). Effluent toxicity was under- or over-estimated by calculating the sum of the TUs of the individual components, depending on which toxicity data and test organisms were used. PMID:11534905

Guerra, R

2001-09-01

48

Sensitivity, robustness, and identifiability in stochastic chemical kinetics models.  

PubMed

We present a novel and simple method to numerically calculate Fisher information matrices for stochastic chemical kinetics models. The linear noise approximation is used to derive model equations and a likelihood function that leads to an efficient computational algorithm. Our approach reduces the problem of calculating the Fisher information matrix to solving a set of ordinary differential equations. This is the first method to compute Fisher information for stochastic chemical kinetics models without the need for Monte Carlo simulations. This methodology is then used to study sensitivity, robustness, and parameter identifiability in stochastic chemical kinetics models. We show that significant differences exist between stochastic and deterministic models as well as between stochastic models with time-series and time-point measurements. We demonstrate that these discrepancies arise from the variability in molecule numbers, correlations between species, and temporal correlations and show how this approach can be used in the analysis and design of experiments probing stochastic processes at the cellular level. The algorithm has been implemented as a Matlab package and is available from the authors upon request. PMID:21551095

Komorowski, Micha?; Costa, Maria J; Rand, David A; Stumpf, Michael P H

2011-05-24

49

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

SciTech Connect

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.

Sinha, D.N.; Springer, K.; Han, W.; Lizon, D.; Kogan, S. [Los Alamos National Lab., NM (United States). Electronic Materials and Devices Group

1997-12-01

50

Identifying Promising Compounds in Drug Discovery: Genetic Algorithms and Some New Statistical Techniques  

E-print Network

Identifying Promising Compounds in Drug Discovery: Genetic Algorithms and Some New Statistical, Michigan 48105 Received December 14, 2006 Throughout the drug discovery process, discovery teams are asked to prioritize compounds for subsequent stages of the drug discovery process, given results from

Wu, Jeff

51

Identifying alkylbenzene isomers with chemical ionization-proton exchange mass spectrometry  

SciTech Connect

Chemical ionization-proton exchange mass spectrometry (CIPE) allows the number of unsubstituted aromatic carbons in alkylbenzene isomers to be determined. Only the aromatic hydrogens undergo exchange with deuterium when deuterated water, methanol, or ethanol is used as the reagent gas. Chemical ionization with deuterated methanol gives an acceptable mass spectral background and allows the determination of the number of unsubstituted positions on the benzene ring yielding structural information often unavailable from conventional electron impact spectra. Structural isomers such as propyl-, methylethyl-, and trimethylbenzene can easily be identified. The comparison of CIPE spectra from standard compounds, which are often unavailable, is not required to determine the number of unsubstituted aromatic carbons in alkylbenzene isomers. The method also allows ortho and para to be distinguished from meta disubstituted alkylbenzenes. Deuteriomethanol chemical ionization is used to characterize alkylbenzenes in a complex and relatively well studied sample, diesel exhaust. 14 references, 3 figures, 3 tables.

Hawthorne, S.B.; Miller, D.J.

1985-03-01

52

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

E-print Network

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.

Labushev, Mikhail M

2013-01-01

53

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

E-print Network

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.

Mikhail M. Labushev

2013-03-20

54

STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS  

PubMed Central

A method has been described by which sensitization to a simple chemical, picryl chloride (2:4:6 trinitrochlorobenzene), can be satisfactorily attained by means of intraperitoneal injection of the compound when killed tubercle bacilli suspended in paraffin oil were used as adjuvant. Sensitivity of the contact dermatitis type results therefrom. It follows that although skin sensitization of this type is most easily obtained by dermal application this route of administration is no necessary condition for such sensitivity. PMID:19870959

Landsteiner, K.; Chase, M. W.

1940-01-01

55

Chemical impurity produces extra compound eyes and heads in crickets  

SciTech Connect

A chemical impurity isolated from commercially purchased acridine causes cricket embryos to develop extra compound eyes, branched antennae, extra antennae, and extra heads. Purified acridine does not produce similar duplications of cricket heads or head structures nor do the substituted acridines proflavine, acriflavine, or acridine orange. A dose-response relation exists such that the number and severity of abnormalities increase with increasing concentration of the teratogen.

Walton, B.T.

1981-04-03

56

GPU Accelerated Chemical Similarity Calculation for Compound Library Comparison  

PubMed Central

Chemical similarity calculation plays an important role in compound library design, virtual screening, and “lead” optimization. In this manuscript, we present a novel GPU-accelerated algorithm for all-vs-all Tanimoto matrix calculation and nearest neighbor search. By taking advantage of multi-core GPU architecture and CUDA parallel programming technology, the algorithm is up to 39 times superior to the existing commercial software that runs on CPUs. Because of the utilization of intrinsic GPU instructions, this approach is nearly 10 times faster than existing GPU-accelerated sparse vector algorithm, when Unity fingerprints are used for Tanimoto calculation. The GPU program that implements this new method takes about 20 minutes to complete the calculation of Tanimoto coefficients between 32M PubChem compounds and 10K Active Probes compounds, i.e., 324G Tanimoto coefficients, on a 128-CUDA-core GPU. PMID:21692447

Ma, Chao; Wang, Lirong; Xie, Xiang-Qun

2012-01-01

57

Use of genotoxicity tests in a TIE to identify chemicals potentially affecting human health  

SciTech Connect

Imperial Oil operates a sour gas processing plant in southern Alberta that has, for the past several years, been the focus of considerable public and regulatory concern over perceived contamination of soils and groundwater on a nearby ranch. Elevated concentrations of DOC ({approximately}140 mg/L) have been received in groundwater underlying the plant site. Two process-related chemicals, sulfolane and diisopropanolamine (DIPA), had been previously identified as the primary components of the DOC plume, although the chemicals associated with 30% of the DOC could not be identified. A risk assessment was initiated in 1994 to determine whether off-site migration of sulfolane and DIPA or of other unidentified contaminants poses a risks to human health and/or ecological receptors. One component of the risk assessment included conducting a TIE to help identify the chemical(s) in contaminated groundwater underlying the gas plant that might adversely affect human health. Three endpoints were utilized in the TIE: MicroTox, SOS-Chromotest and the Ames test. MicroTox was used since it exhibited a response to whole groundwater from the site, while the genotoxicity tests were used because DIPA reportedly causes a response in the Ames test and because of the concern over potential human health affects arising from other unidentified contaminants. Results of the TIE indicated that the chemicals causing the toxicity in the groundwater sample were water soluble compounds, with similar characteristics to the process chemicals used at the gas plant and detected at high concentrations in groundwater from the plant site. These results provided additional evidence to help focus the risk assessment on the chemicals sulfolane and diisopropanolamine.

Goudey, J.S. [HydroQual Labs. Ltd., Calgary, Alberta (Canada); Shaw, R.D.; Swanson, S.M. [Golder Associates Ltd., Calgary, Alberta (Canada); Nadeau, S. [Imperial Oil Resources Ltd., Calgary, Alberta (Canada)

1995-12-31

58

Chemical-genetic profile analysis of five inhibitory compounds in yeast  

PubMed Central

Background Chemical-genetic profiling of inhibitory compounds can lead to identification of their modes of action. These profiles can help elucidate the complex interactions between small bioactive compounds and the cell machinery, and explain putative gene function(s). Results Colony size reduction was used to investigate the chemical-genetic profile of cycloheximide, 3-amino-1,2,4-triazole, paromomycin, streptomycin and neomycin in the yeast Saccharomyces cerevisiae. These compounds target the process of protein biosynthesis. More than 70,000 strains were analyzed from the array of gene deletion mutant yeast strains. As expected, the overall profiles of the tested compounds were similar, with deletions for genes involved in protein biosynthesis being the major category followed by metabolism. This implies that novel genes involved in protein biosynthesis could be identified from these profiles. Further investigations were carried out to assess the activity of three profiled genes in the process of protein biosynthesis using relative fitness of double mutants and other genetic assays. Conclusion Chemical-genetic profiles provide insight into the molecular mechanism(s) of the examined compounds by elucidating their potential primary and secondary cellular target sites. Our follow-up investigations into the activity of three profiled genes in the process of protein biosynthesis provided further evidence concerning the usefulness of chemical-genetic analyses for annotating gene functions. We termed these genes TAE2, TAE3 and TAE4 for translation associated elements 2-4. PMID:20691087

2010-01-01

59

A High-Throughput Method to Identify Novel Senescence-Inducing Compounds  

PubMed Central

Cellular senescence is a persistently growth-arrested phenotype in normal and transformed cells induced by non-cytotoxic stress. Cytostasis as a method of cancer treatment has recently generated significant interest. Research into the induction of cellular senescence as cancer therapy has been hindered by a lack of compounds that efficiently induce this response. We describe a semiautomated high-throughput method to identify library compounds that induce senescence using prostate cancer cells cultured in 96 well plates. Primary hits are identified by low cell numbers after 3 days in culture, measured by Hoechst 33342 fluorescence. A secondary visual assessment of senescence-associated ?-galactosidase staining and cellular morphology in the same wells distinguishes senescence from quiescence, apoptosis and other false-positives. This method was used to screen a 4160 compound library of known bioactive compounds and natural products at a 10?M dose. Candidate compounds were further selected based on persistent growth arrest after drug removal and increased expression of previously described senescence marker genes. Four lead compounds not previously associated with senescence were identified for further investigation. This is the first successful assay to identify novel agents from compound libraries based on senescence-induction in cancer cells. PMID:19641224

Ewald, Jonathan A.; Peters, Noel; Desotelle, Joshua A.; Hoffmann, F. Michael; Jarrard, David F.

2010-01-01

60

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

PubMed

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

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

2014-06-30

61

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

SciTech Connect

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.

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

2010-09-20

62

30 CFR 47.21 - Identifying hazardous chemicals.  

Code of Federal Regulations, 2010 CFR

...may choose to evaluate the chemical using the criteria in paragraphs...c) of this table. (b) Chemical produced at the mine The chemical is hazardous if any one of...that could present a health risk to miners, assume that...

2010-07-01

63

Identifying inhibitory compounds in lignocellulosic biomass hydrolysates using an exometabolomics approach  

PubMed Central

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

2014-01-01

64

Identifying new persistent and bioaccumulative organics among chemicals in commerce II: pharmaceuticals.  

PubMed

The goal of this study was to identify commercial pharmaceuticals that might be persistent and bioaccumulative (P&B) and that were not being considered in current wastewater and aquatic environmental measurement programs. We developed a database of 3193 pharmaceuticals from two U.S. Food and Drug Administration (FDA) databases and some lists of top ranked or selling drugs. Of the 3193 pharmaceuticals, 275 pharmaceuticals have been found in the environment and 399 pharmaceuticals were, based upon production volumes, designated as high production volume (HPV) pharmaceuticals. All pharmaceuticals that had reported chemical structures were evaluated for potential bioaccumulation (B) or persistence (P) using quantitative structure property relationships (QSPR) or scientific judgment. Of the 275 drugs detected in the environment, 92 were rated as potentially bioaccumulative, 121 were rated as potentially persistent, and 99 were HPV pharmaceuticals. After removing the 275 pharmaceuticals previously detected in the environment, 58 HPV compounds were identified that were both P&B and 48 were identified as P only. Of the non-HPV compounds, 364 pharmaceuticals were identified that were P&B. This study has yielded some interesting and probable P&B pharmaceuticals that should be considered for further study. PMID:21740030

Howard, Philip H; Muir, Derek C G

2011-08-15

65

Electrolytic photodissociation of chemical compounds by iron oxide photochemical diodes  

DOEpatents

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.

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

1985-01-01

66

Electrolytic photodissociation of chemical compounds by iron oxide electrodes  

DOEpatents

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.

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

1984-01-01

67

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

PubMed Central

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

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

2012-01-01

68

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

PubMed Central

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

2014-01-01

69

A framework for identifying characteristic odor compounds in municipal wastewater effluent.  

PubMed

Municipal wastewater often contains trace amounts of organic compounds that can compromise aesthetics of drinking water and undermine public confidence if a small amount of effluent enters the raw water source of a potable water supply. To efficiently identify compounds responsible for odors in wastewater effluent, an analytical framework consisting of gas chromatography with mass spectrometry (GC-MS) and gas chromatography with olfactometry detection (GC-Olf) coupled with flavor profile analysis (FPA) was used to identify and monitor compounds that could affect the aesthetics of drinking water. After prioritizing odor peaks detected in wastewater effluent by GC-Olf, the odorous components were tentatively identified using retention indices, mass spectra and odor descriptors. Wastewater effluent samples were typically dominated by earthy-musty odors with additional odors in the amine, sulfidic and fragrant categories. 2,4,6-trichloroanisole (246TCA), geosmin and 2-methylisoborneol (2MIB) were the main sources of the earthy/musty odors in wastewater effluent. The other odors were attributable to a suite of compounds, which were detected in some but not all of the wastewater effluents at levels well in excess of their odor thresholds. In most cases, the identities of odorants were confirmed using authentic standards. The fate of these odorous compounds, including 2-pyrrolidone, methylnaphthalenes, vanillin and 5-hydroxyvanillin (5-OH-vanillin), should be considered in future studies of water systems that receive effluent from upstream sources. PMID:22981490

Agus, Eva; Zhang, Lifeng; Sedlak, David L

2012-11-15

70

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

71

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

PubMed Central

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

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

2005-01-01

72

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

PubMed Central

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

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

73

Identifying Indicators of Reactivity for Chemical Reductants in Sediments  

EPA Science Inventory

To conduct site-specific exposure assessments for contaminants containing reducible functional groups, it is imperative to know the identity and reactivity of chemical reductants in natural sediments and to associate their reactivity with easily measurable sediment properties. Fo...

74

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...

75

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...

76

Risk assessment of endocrine active chemicals: identifying chemicals of regulatory concern.  

PubMed

The European regulation on plant protection products (1107/2009) (EC, 2009a), the revisions to the biocides Directive (COM[2009]267) (EC, 2009b), and the regulation concerning chemicals (Regulation (EC) No. 1907/2006 'REACH') (EC.2006) only support the marketing and use of chemical products on the basis that they do not induce endocrine disruption in humans or wildlife species. In the absence of agreed guidance on how to identify and evaluate endocrine activity and disruption within these pieces of legislation a European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) task force was formed to provide scientific criteria that may be used within the context of these three legislative documents. The resulting ECETOC technical report (ECETOC, 2009a) and the associated workshop (ECETOC, 2009b) presented a science-based concept on how to identify endocrine activity and disrupting properties of chemicals for both human health and the environment. The synthesis of the technical report and the workshop report was published by the ECETOC task force (Bars et al., 2011a,b). Specific scientific criteria for the determination of endocrine activity and disrupting properties that integrate information from both regulatory (eco)toxicity studies and mechanistic/screening studies were proposed. These criteria combined the nature of the adverse effects detected in studies which give concern for endocrine toxicity with an understanding of the mode of action of toxicity so that adverse effects can be explained scientifically. A key element in the data evaluation is the consideration of all available information in a weight-of-evidence approach. However, to be able to discriminate chemicals with endocrine properties of low concern from those of higher concern (for regulatory purposes), the task force recognised that the concept needed further refinement. Following a discussion of the key factors at a second workshop of invited regulatory, academic and industry scientists (ECETOC, 2011), the task force developed further guidance, which is presented in this paper. For human health assessments these factors include the relevance to humans of the endocrine mechanism of toxicity, the specificity of the endocrine effects with respect to other potential toxic effects, the potency of the chemical to induce endocrine toxicity and consideration of exposure levels. For ecotoxicological assessments the key considerations include specificity and potency, but also extend to the consideration of population relevance and negligible exposure. It is intended that these complement and reinforce the approach originally described and previously published in this journal (Bars et al., 2011a,b). PMID:22735369

Bars, Remi; Fegert, Ivana; Gross, Melanie; Lewis, Dick; Weltje, Lennart; Weyers, Arnd; Wheeler, James R; Galay-Burgos, Malyka

2012-10-01

77

UniChem: a unified chemical structure cross-referencing and identifier tracking system.  

PubMed

UniChem is a freely available compound identifier mapping service on the internet, designed to optimize the efficiency with which structure-based hyperlinks may be built and maintained between chemistry-based resources. In the past, the creation and maintenance of such links at EMBL-EBI, where several chemistry-based resources exist, has required independent efforts by each of the separate teams. These efforts were complicated by the different data models, release schedules, and differing business rules for compound normalization and identifier nomenclature that exist across the organization. UniChem, a large-scale, non-redundant database of Standard InChIs with pointers between these structures and chemical identifiers from all the separate chemistry resources, was developed as a means of efficiently sharing the maintenance overhead of creating these links. Thus, for each source represented in UniChem, all links to and from all other sources are automatically calculated and immediately available for all to use. Updated mappings are immediately available upon loading of new data releases from the sources. Web services in UniChem provide users with a single simple automatable mechanism for maintaining all links from their resource to all other sources represented in UniChem. In addition, functionality to track changes in identifier usage allows users to monitor which identifiers are current, and which are obsolete. Lastly, UniChem has been deliberately designed to allow additional resources to be included with minimal effort. Indeed, the recent inclusion of data sources external to EMBL-EBI has provided a simple means of providing users with an even wider selection of resources with which to link to, all at no extra cost, while at the same time providing a simple mechanism for external resources to link to all EMBL-EBI chemistry resources. PMID:23317286

Chambers, Jon; Davies, Mark; Gaulton, Anna; Hersey, Anne; Velankar, Sameer; Petryszak, Robert; Hastings, Janna; Bellis, Louisa; McGlinchey, Shaun; Overington, John P

2013-01-01

78

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

PubMed Central

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

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

2014-01-01

79

Constructing Chemical Pathways of Organic Compounds in Titan's Atmosphere  

NASA Astrophysics Data System (ADS)

The CURE/Cassini Imaging Project has provided resources in acquiring images of the Saturnian system using the Imaging Science Subsystem Narrow-Angle Camera (ISS NAC) on board Cassini. Twenty eight images of Titan were taken during March 2, 2006, August 10, 2006, September 12, 2006 and May 4, 2007. Titan is the largest satellite of Saturn with a thick atmosphere consisting of 98% N2 and 2% CH4. Studying Titan's atmosphere can provide a better understanding of pre-biotic Earth due to its nitrogen based atmosphere and due to the photochemical interactions of organic compounds occurring within the atmosphere, as well as with Titan's surface features. In studies prior to the arrival of Cassini-Huygens, microphysical models examined particles, referred to as fractal aggregates and tholins, in Titan's atmosphere exhibiting similar optical properties observed during Voyager flybys. Literature research was conducted of Titan's atmosphere in order to map out the expected chemical pathways of the aerosol particles and to figure out the structure and composition of the atmosphere. The formation of haze particle layers is largely caused by the photolysis and polymerization of CH4, and the haze layers obstruct visible and UV light from illuminating surface features of Titan due to its complex scattering and absorption properties. An accurate illustration of the haze formation process is still under development, however, observations show that the main haze is located below the stratosphere (altitude <= 220 km), consisting of end compounds such as polyacetylene (C2H2), polycyclic aromatic hydrocarbons (PAH), and heavy nitriles. A diagram of the chemical reactions in Titan's atmosphere will be presented using the evidence found in the research. Further investigation into developing an accurate representation of the aerosol particle size, composition, and formation mechanism in Titan's atmosphere can be used in conjunction with observational data to create a model of the atmosphere.

Lee, Agustin; Gillam, S.; Bhakta, J.

2009-05-01

80

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

PubMed

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

Torres, Alexia

2012-12-01

81

Yeast-based automated high-throughput screens to identify anti-parasitic lead compounds  

PubMed Central

We have developed a robust, fully automated anti-parasitic drug-screening method that selects compounds specifically targeting parasite enzymes and not their host counterparts, thus allowing the early elimination of compounds with potential side effects. Our yeast system permits multiple parasite targets to be assayed in parallel owing to the strains’ expression of different fluorescent proteins. A strain expressing the human target is included in the multiplexed screen to exclude compounds that do not discriminate between host and parasite enzymes. This form of assay has the advantages of using known targets and not requiring the in vitro culture of parasites. We performed automated screens for inhibitors of parasite dihydrofolate reductases, N-myristoyltransferases and phosphoglycerate kinases, finding specific inhibitors of parasite targets. We found that our ‘hits’ have significant structural similarities to compounds with in vitro anti-parasitic activity, validating our screens and suggesting targets for hits identified in parasite-based assays. Finally, we demonstrate a 60 per cent success rate for our hit compounds in killing or severely inhibiting the growth of Trypanosoma brucei, the causative agent of African sleeping sickness. PMID:23446112

Bilsland, Elizabeth; Sparkes, Andrew; Williams, Kevin; Moss, Harry J.; de Clare, Michaela; Pir, P?nar; Rowland, Jem; Aubrey, Wayne; Pateman, Ron; Young, Mike; Carrington, Mark; King, Ross D.; Oliver, Stephen G.

2013-01-01

82

Detailed Chemical Kinetic Reaction Mechanisms for Incineration of Organophosphorus and Fluoro-Organophosphorus Compounds  

SciTech Connect

A detailed chemical kinetic reaction mechanism is developed to describe incineration of the chemical warfare nerve agent sarin (GB), based on commonly used principles of bond additivity and hierarchical reaction mechanisms. The mechanism is based on previous kinetic models of organophosphorus compounds such as TMP, DMMP and DIMP that are often used as surrogates to predict incineration of GB. Kinetic models of the three surrogates and GB are then used to predict their consumption in a perfectly stirred reactor fueled by natural gas to simulate incineration of these chemicals. Computed results indicate that DIMP is the only one of these surrogates that adequately describes combustion of GB under comparable conditions. The kinetic pathways responsible for these differences in reactivity are identified and discussed. The most important reaction in GB and DIMP that makes them more reactive than TMP or DMMP is found to be a six-center molecular elimination reaction producing propene.

Glaude, P A; Melius, C; Pitz, W J; Westbrook, C K

2001-12-13

83

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

USGS Publications Warehouse

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.

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

1997-01-01

84

Chemical Modification of the Multi-Target Neuroprotective Compound Fisetin  

PubMed Central

Many factors are implicated in age-related CNS disorders making it unlikely that modulating only a single factor will provide effective treatment. Perhaps a better approach is to identify small molecules that have multiple biological activities relevant to the maintenance of brain function. Recently, we identified an orally active, neuroprotective and cognition-enhancing molecule, the flavonoid fisetin, that is effective in several animal models of CNS disorders. Fisetin has direct antioxidant activity and can also increase the intracellular levels of glutathione (GSH), the major endogenous antioxidant. In addition, fisetin has both neurotrophic and anti-inflammatory activity. However, its relatively high EC50 in cell based assays, low lipophilicity, high tPSA and poor bioavailability suggest that there is room for medicinal chemical improvement. Here we describe a multi-tiered approach to screening that has allowed us to identify fisetin derivatives with significantly enhanced activity in an in vitro neuroprotection model while at the same time maintaining other key activities. PMID:22192055

Chiruta, Chandramouli; Schubert, David; Dargusch, Richard; Maher, Pamela

2012-01-01

85

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

E-print Network

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...

Labushev, Mikhail M

2011-01-01

86

Identifying the macromolecular targets of de novo-designed chemical entities through self-organizing map consensus  

PubMed Central

De novo molecular design and in silico prediction of polypharmacological profiles are emerging research topics that will profoundly affect the future of drug discovery and chemical biology. The goal is to identify the macromolecular targets of new chemical agents. Although several computational tools for predicting such targets are publicly available, none of these methods was explicitly designed to predict target engagement by de novo-designed molecules. Here we present the development and practical application of a unique technique, self-organizing map–based prediction of drug equivalence relationships (SPiDER), that merges the concepts of self-organizing maps, consensus scoring, and statistical analysis to successfully identify targets for both known drugs and computer-generated molecular scaffolds. We discovered a potential off-target liability of fenofibrate-related compounds, and in a comprehensive prospective application, we identified a multitarget-modulating profile of de novo designed molecules. These results demonstrate that SPiDER may be used to identify innovative compounds in chemical biology and in the early stages of drug discovery, and help investigate the potential side effects of drugs and their repurposing options. PMID:24591595

Reker, Daniel; Rodrigues, Tiago; Schneider, Petra; Schneider, Gisbert

2014-01-01

87

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

SciTech Connect

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.

Stone, Alex, E-mail: alst461@ecy.wa.go [Washington State Department of Ecology, P.O. Box 47600, Olympia, WA 98504-7600 (United States); Delistraty, Damon, E-mail: ddel461@ecy.wa.go [Washington State Department of Ecology, Spokane, WA 99205-1295 (United States)

2010-11-15

88

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

Microsoft Academic Search

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

Alex Stone; Damon Delistraty

2010-01-01

89

Chemical reactivity and biological activity of chalcones and other ?,?-unsaturated carbonyl compounds.  

PubMed

Abstract 1. Chalcones are structural analogues of benzalacetophenone (BAP). Several derivatives have been identified in plants and anticarcinogenic and anti-inflammatory properties were attributed to the compounds, probably related to their direct antioxidant activity or stimulatory effects on the expression of endogenous defence enzymes like hemeoxygenase-1 (HO-1). HO-1 expression is triggered by the Nrf2-Keap1 signalling pathway, initiated by the addition of chalcones to thiol groups of Keap1 via Michael-type reaction. 2. The present study used a model system estimating the reactivity of different synthetic chalcones and other ?,?-unsaturated carbonyl compounds with thiols and compared the chemical reactivity with the biological activity, measured by HO-1 expression in human dermal fibroblasts. 3. Chemical reactivity with the thiol group of N-acetylcysteine was determined with 5,5'-dithiobis-(2-nitrobenzoic acid) and followed chemical principles of structure-reactivity relationship. Most reactive were sulforaphane, dimethylfumarate, chalcone 3 ((2E)-1-phenyl-3-pyrimidin-2-ylprop-2-en-1-one) and chalcone 7 (1,3-diphenylprop-2-yn-1-one). This result demonstrates that ?,?-unsaturated carbonyl derivatives react with thiols differently. All compounds were also biologically active; however, expression of HO-1 was not only related to the chemical reactivity but also to the lipophilicity of the molecules which likely affected transmembrane uptake. Most efficient inducers of HO-1 expression were BAP, 4-hydroxynonenal and chalcone 1 (4-[(1E)-3-oxo-3-phenylprop-1-en-1-yl]benzonitrile), chalcone 5 ((2E)-1-phenyl-3-[4-(trifluoromethyl)-phenyl]prop-2-en-1-one) and chalcone 7. PMID:23339572

Maydt, Daniela; De Spirt, Silke; Muschelknautz, Christian; Stahl, Wilhelm; Müller, Thomas J J

2013-08-01

90

A small molecule screen identifies a novel compound that induces a homeotic transformation in Hydra.  

PubMed

Developmental processes such as morphogenesis, patterning and differentiation are continuously active in the adult Hydra polyp. We carried out a small molecule screen to identify compounds that affect patterning in Hydra. We identified a novel molecule, DAC-2-25, that causes a homeotic transformation of body column into tentacle zone. This transformation occurs in a progressive and polar fashion, beginning at the oral end of the animal. We have identified several strains that respond to DAC-2-25 and one that does not, and we used chimeras from these strains to identify the ectoderm as the target tissue for DAC-2-25. Using transgenic Hydra that express green fluorescent protein under the control of relevant promoters, we examined how DAC-2-25 affects tentacle patterning. Genes whose expression is associated with the tentacle zone are ectopically expressed upon exposure to DAC-2-25, whereas those associated with body column tissue are turned off as the tentacle zone expands. The expression patterns of the organizer-associated gene HyWnt3 and the hypostome-specific gene HyBra2 are unchanged. Structure-activity relationship studies have identified features of DAC-2-25 that are required for activity and potency. This study shows that small molecule screens in Hydra can be used to dissect patterning processes. PMID:24255098

Glauber, Kristine M; Dana, Catherine E; Park, Steve S; Colby, David A; Noro, Yukihiko; Fujisawa, Toshitaka; Chamberlin, A Richard; Steele, Robert E

2013-12-01

91

Tailoring of a photoactive compound for non-chemically amplified 248-nm resist formulations  

NASA Astrophysics Data System (ADS)

Several approaches toward the design of non-chemically amplified deep UV resists have been reported using different photoactive compounds and resins. Diazo-dione chromophores are particularly attractive for this application, but the keto- ketenes derived from their photolysis are more reactive than those derived from the analogous diazonaphthoquinones. Specifically, the 30-diazo-4-ketocoumarin chromophore has been identified as a promising candidate around which to design a non-chemically amplified 248 nm resist. In order to optimize the design of this system, the influence of both electronic and steric influences on the rate of reaction of the ketene with novolac resin has been studied. These experiments were carried out using a low temperature matrix isolation FT-IR technique similar to that previously reported. The reaction of the ketene with the resin hydroxyl group follows pseudo first order kinetics and the rate constant is dependent on the substituents and the substitution pattern on the coumarin.

Leeson, Michael J.; Pawloski, Adam R.; Levering, Vrad; Yueh, Wang; Willson, C. Grant

1997-07-01

92

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

PubMed Central

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

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

93

Emission and Chemical Transformation of Biogenic Volatile Organic Compounds (echo)  

NASA Astrophysics Data System (ADS)

Forests are complex sources of biogenic volatile organic compounds (VOC) in the planetary boundary layer. The impact of biogenic VOC on tropospheric photochem- istry, air quality, and the formation of secondary products affects our climate on a regional and global scale but is far from being understood. A considerable lack of knowledge exists concerning a forest stand as a net source of reactive trace com- pounds, which are transported directly into the planetary boundary layer (PBL). In particular, little is known about the amounts of VOC which are processed within the canopy. The goal of ECHO, which is presented in this poster, is to investigate these questions and to improve our understanding of biosphere-atmosphere interactions and their effects on the PBL. The investigation of emissions, chemical processing and vertical transport of biogenic VOC will be carried out in and above a mixed forest stand in Jülich, Germany. A large set of trace gases, free radicals and meteorologi- cal parameters will be measured at different heights in and above the canopy, covering concentrations of VOC, CO, O3, organic nitrates und NOx as well as organic aerosols. For the first time concentration profiles of OH, HO2, RO2 und NO3 radicals will be measured as well together with the actinic UV radiation field and photolysis frequen- cies of all relevant radical precursors (O3, NO2, peroxides, oxygenated VOC). The different tasks of the field experiments will be supported by simulation experiments investigating the primary emission and the uptake of VOC by the plants in stirred tank reactors, soil parameters and soil emissions in lysimeter experiments, and the chem- ical processing of the trace gases as observed in and above the forest stand in the atmosphere simulation chamber SAPHIR. The planning and interpretation of the field experiments is supported by simulations of the field site in a wind tunnel.

Koppmann, R.; Hoffmann, T.; Kesselmeier, J.; Schatzmann, M.

94

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

95

Oxidative properties and chemical stability of fluoronanotubes in matrixes of binary inorganic compounds.  

PubMed

The chemical stability of fluoronanotubes in selected solid inorganic matrixes has been studied by initially mixing and mechanically grinding the components and subsequently heating them at temperatures ranging from 35 to 600 degrees C. The inorganic compounds selected for matrixes included halides (KBr, KI, Lil, LiBr, LiCl, NaCl, Znl2), oxides (Li2O, Fe2O3, PbO, MnO), lithium peroxide (Li2O2), potassium superoxide (KO2), sulfides (Li2S and ZnS), zinc selenide (ZnSe), lithium nitride (Li3N), and aluminum phosphide (AIP). Solid products, resulting from the proceeding chemical reactions, were analyzed by X-ray diffraction, Raman spectroscopy, and SEM/EDX elemental analysis. Gaseous and volatile products were identified with the help of the TGA/MS technique. Experimental data presented in this paper provide clear evidence that fluoronanotubes are not chemically inert toward the solid matrixes studied and exhibit significant oxidative properties in the redox reactions occurring under various temperatures, depending on the nature of the inorganic compound. PMID:12908234

Peng, Haiqing; Gu, Zhenning; Liu, Yu; Chiang, Ivana W; Smalley, Richard E; Hauge, Robert H; Khabashesku, Valery N; Margrave, John L

2003-01-01

96

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 ...

97

Statistical methods for the chemical compound identification from neutron-induced gamma-ray spectra  

Microsoft Academic Search

The paper presents a list correlation method to identify specific high explosive (HE) compounds from the spectra derived from reconstructed images of a gamma- ray camera. The correlation method uses all the information of the characteristic gamma rays for the associated elements of a compound. We show that the method is able to identify HE material at the compound level

Randy C. Stevenson; Joonki Noh; Mark D. Hammig

2009-01-01

98

E-prescribing errors identified in a compounding pharmacy: a quality-improvement project.  

PubMed

Errors during the prescribing process can cause problems for patients. When the pharmacist intercepts a prescribing error, it can cause a delay, as the patient may not receive the medication until the problem is resolved. Electronic prescriptions are purported to reduce prescribing errors. However, studies have shown that electronic prescriptions can be prone to certain types of errors. Compounding pharmacies may present an additional obstacle for e-prescribing, as the prescribed medications are not commercially available and may not be listed in the e-prescribing software. The objectives of this study were to estimate the electronic prescription error rate in a compounding pharmacy, determine the most common error types, list the most common interventions pharmacists made, and estimate how long it took to resolve these errors. The study design was quality improvement with descriptive data. During the four weeks of data collection, the pharmacists were trained to complete a standardized data collection form when they identified an electronic prescription error. Percentages were calculated for new prescriptions, electronic prescriptions with errors, error types, and error resolution methods. In the four-week period of the study, there were 982 new prescriptions, 111 of which were electronic prescriptions. Of those 111 electronic prescriptions, 70 had errors. The electronic prescriptions error rate was 63%. The most common type of error was wrong entry field (70.3%). For this project, wrong entry field was defined to mean that the drug name was in the wrong field (81%) or that multiple entries were in the wrong field (7%). Pharmacists usually used their own judgment to resolve an error (67%). Many e-prescription errors were identified in this compounding pharmacy. When prescription errors happen, workflow and patient care are disrupted. Our goal is to discuss these findings with Surescripts and e-prescribing software companies to seek systems-based solutions. PMID:24881345

Reed-Kane, Dana; Kittell, Katrina; Adkins, Jacquelyn; Flocks, Sarah; Nguyen, Thu

2014-01-01

99

Apatite formation: why it may not work as planned, and how to conclusively identify apatite compounds.  

PubMed

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

Drouet, Christophe

2013-01-01

100

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

PubMed Central

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

2013-01-01

101

[The effect of selected tannery chemical compounds on selected bacteria of activated sludge].  

PubMed

Influence of tannery chemical compounds on the selected bacteria of the activated sludge was investigated. The chromium compounds must be diluted to 1:15-1:20 to loss its activity on the bacteria. Other compounds like: natrium chloratum, natrium formate and greased oils have any influence on the growth of the selected bacteria. PMID:11286092

Mendrycka, M; Mierzejewski, J; Lidacki, A; Smiechowski, K

2000-01-01

102

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

PubMed

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

Hauschild, Veronique D; Watson, Annetta

2013-01-01

103

T-Screen as a tool to identify thyroid hormone receptor active compounds.  

PubMed

The T-Screen represents an in vitro bioassay based on thyroid hormone dependent cell proliferation of a rat pituitary tumour cell line (GH3) in serum-free medium. It can be used to study interference of compounds with thyroid hormone at the cellular level, thus bridging the gap between limitations of assays using either isolated molecules (enzymes, transport proteins) or complex in vivo experiments with all the complex feedback mechanisms present. Compounds are tested both in the absence and presence of thyroid hormone (EC(50) concentration of T(3)) to test for both agonistic and antagonistic potency. Thyroid hormones (3,3'-5-triiodothyronine: T(3) and 3,3',5,5'-tetraiodothyroxine: T(4)) and compounds resembling the structure of thyroid hormones (3,3'-5-triiodothyroacetic acid: Triac; 3,3',5,5'-tetraiodothyroacetic acid: Tetrac) induced cell growth, with the rank order Triac > T(3) > Tetrac > T(4) (relative potency = 1.35 > 1 > 0.29 > 0.07), which is identical to published affinities of these compounds for nuclear thyroid hormone receptors. Exposure to 5,5'-diphenylhydantoin (DPH) in the presence of 0.25nM T(3) resulted in up to 60% decreased cell growth at 200?M DPH. No effect of DPH on basal metabolic activity of GH3 cells was observed at this concentration. Fentinchloride (IC(50) = 21nM) decreased cell growth induced by 0.25nM T(3), whereas parallel exposure to these concentrations in the absence of T(3) did not alter basal metabolic activities of GH3 cells. Apolar sediment extracts from the Dommel (34%) and Terneuzen (14%) decreased cell growth in the presence of 0.25nM T(3), whereas the extract from Hoogeveen increased cell growth (26%) and the extract from North Sea Channel had no effect. The T-Screen proved to be a fast and functional assay for assessing thyroid hormone receptor active potencies of pure chemicals or environmental mixtures. PMID:21783481

Gutleb, Arno C; Meerts, Ilonka A T M; Bergsma, Joost H; Schriks, Merijn; Murk, Albertinka J

2005-02-01

104

Polyphenolic compounds as chemical markers of wine ageing in contact with cherry, chestnut, false acacia, ash and oak wood.  

PubMed

The nonanthocyanic phenolic composition of four red wines, one white, and one rosé aged using barrels and chips of cherry, chestnut, false acacia, ash and oak wood was studied by LC-DAD-ESI/MS, to identify the phenolic compounds that woods other than oak contribute to wines, and if some of them can be used as chemical markers of ageing with them. A total of 68 nonanthocyanic phenolic compounds were identified, 15 found only in wines aged with acacia wood, 6 with cherry wood, and 1 with chestnut wood. Thus, the nonanthocyanic phenolic profile could be a useful tool to identify wines aged in contact with these woods. In addition, some differences in the nonanthocyanic phenolic composition of wines were detected related to both the levels of compounds provided by each wood species and the different evolution of flavonols and flavanols in wines during ageing in barrels or in contact with chips. PMID:24054214

Fernández de Simón, B; Sanz, M; Cadahía, E; Martínez, J; Esteruelas, E; Muñoz, A M

2014-01-15

105

Psychoactive plants described in a Brazilian literary work and their chemical compounds.  

PubMed

Ethnopharmacological research investigates the plants and other medicinal and toxic substances utilized by different traditional populations. One approach in this field is a literature search of the available publications on medicinal plants. The purpose of the current study was to select plants with psychoactive effects described in a Brazilian literary work written by Pio Correa in 1926. Those mentioned plants were classified in accordance with their indications for use as stimulants and depressors of the central nervous system. For the phytochemical study herein, we researched these species via a database search, and all the obtained information was compiled into a new database to analyze possible correlations between the chemical compounds and the psychoactive categories. Of the 813 plants searched in the literary work, 104 presented chemical data in the scientific periodicals consulted. Seventy-five of them belong to the stimulant category, while 31 are depressors and two of them belong to both categories. Phenols and flavonoids were the main compounds observed in plants of both categories, though at different frequencies. Monoterpenes (29.9%) and sesquiterpenes (28.6%) were also observed in plants from the stimulant category, while 25.8% of plants from the depressor category were comprised of carotenoids and 22.6% of steroids. The main specific compounds were identified as ferulic acid, ?-pinene, limonene, ?-humulene and kaempferol among the stimulant plants. Otherwise, in depressor plants were characterized caffeic acid, kaempferol, quercetin, ?-carotene, physalins and withanolides as specific compounds. The association between ethnopharmacological and chemotaxonomic data, as presented in this study, could support plant selection in further investigations by research groups whose studies focus on psychoactive plants as potential therapeutics. PMID:20557283

Otsuka, Rafaela Denise; Lago, João Henrique Ghilardi; Rossi, Lucia; Galduróz, José Carlos Fernandes; Rodrigues, Eliana

2010-09-01

106

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

NASA Technical Reports Server (NTRS)

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.

White, W. F.

1974-01-01

107

A high throughput pharmaceutical screen identifies compounds with specific toxicity against BRCA2-deficient tumors  

PubMed Central

Purpose: Hereditary breast cancer is partly explained by germline mutations in BRCA1 and BRCA2. While patients carry heterozygous mutations, their tumors have typically lost the remaining wild-type allele. Selectively targeting BRCA-deficiency may therefore constitute an important therapeutic approach. Clinical trials applying this principle are underway, but it is unknown whether the compounds tested are optimal. It is therefore important to identify alternative compounds that specifically target BRCA-deficiency and to test new combination therapies to establish optimal treatment strategies. Experimental Design: We performed a high-throughput pharmaceutical screen on BRCA2-deficient mouse mammary tumor cells and isogenic controls with restored BRCA2 function. Subsequently, we validated positive hits in vitro and in vivo using mice carrying BRCA2-deficient mammary tumors. Results: Three alkylators – chlorambucil, melphalan and nimustine – displayed strong and specific toxicity against BRCA2-deficient cells. In vivo, these showed heterogeneous but generally strong BRCA2-deficient antitumor activity, with melphalan and nimustine outperforming cisplatin and the poly-(ADP-ribose)-polymerase (PARP) inhibitor olaparib (AZD2281) in this small study. In vitro drug combination experiments showed synergistic interactions between the alkylators and olaparib. Tumor intervention studies combining nimustine and olaparib resulted in recurrence-free survival exceeding 330 days in 3 out of 5 animals tested. Conclusions: We generated and validated a platform for identification of compounds with specific activity against BRCA2-deficient cells that translates well to the preclinical setting. Our data call for the re-evaluation of alkylators – especially melphalan and nimustine – alone or in combination with PARP inhibitors for the treatment of breast cancers with a defective BRCA pathway. PMID:20008842

Evers, Bastiaan; Schut, Eva; van der Burg, Eline; Braumuller, Tanya M.; Egan, David A.; Holstege, Henne; Edser, Pauline; Adams, David J.; Wade-Martins, Richard; Bouwman, Peter; Jonkers, Jos

2009-01-01

108

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

E-print Network

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

Sperduti, Alessandro

109

Virtual Screening for LPA2-Specific Agonists Identifies a Nonlipid Compound with Antiapoptotic ActionsS?  

PubMed Central

Lysophosphatidic acid (LPA) is a highly potent endogenous lipid mediator that protects and rescues cells from programmed cell death. Earlier work identified the LPA2 G protein-coupled receptor subtype as an important molecular target of LPA mediating antiapoptotic signaling. Here we describe the results of a virtual screen using single-reference similarity searching that yielded compounds 2-((9-oxo-9H-fluoren-2-yl)carbamoyl)benzoic acid (NSC12404), 2-((3-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)propyl)thio)benzoic acid (GRI977143), 4,5-dichloro-2-((9-oxo-9H-fluoren-2-yl)carbamoyl)benzoic acid (H2L5547924), and 2-((9,10-dioxo-9,10-dihydroanthracen-2-yl)carbamoyl) benzoic acid (H2L5828102), novel nonlipid and drug-like compounds that are specific for the LPA2 receptor subtype. We characterized the antiapoptotic action of one of these compounds, GRI977143, which was effective in reducing activation of caspases 3, 7, 8, and 9 and inhibited poly(ADP-ribose)polymerase 1 cleavage and DNA fragmentation in different extrinsic and intrinsic models of apoptosis in vitro. Furthermore, GRI977143 promoted carcinoma cell invasion of human umbilical vein endothelial cell monolayers and fibroblast proliferation. The antiapoptotic cellular signaling responses were present selectively in mouse embryonic fibroblast cells derived from LPA1&2 double-knockout mice reconstituted with the LPA2 receptor and were absent in vector-transduced control cells. GRI977143 was an effective stimulator of extracellular signal-regulated kinase 1/2 activation and promoted the assembly of a macromolecular signaling complex consisting of LPA2, Na+-H+ exchange regulatory factor 2, and thyroid receptor interacting protein 6, which has been shown previously to be a required step in LPA-induced antiapoptotic signaling. The present findings indicate that nonlipid LPA2-specific agonists represent an excellent starting point for development of lead compounds with potential therapeutic utility for preventing the programmed cell death involved in many types of degenerative and inflammatory diseases. PMID:22968304

Kiss, Gyongyi N.; Fells, James I.; Gupte, Renuka; Lee, Sue-Chin; Liu, Jianxiong; Nusser, Nora; Lim, Keng G.; Ray, Ramesh M.; Lin, Fang-Tsyr; Parrill, Abby L.; Sumegi, Balazs; Miller, Duane D.

2012-01-01

110

Microscopic physical and chemical properties of graphite intercalation compounds  

SciTech Connect

Optical spectroscopy (Raman, FTIR and Reflection ) was used to study a variety of acceptor- and donor-type compounds synthesized to determine the microscopic models consistent with the spectrocsopic results. General finding is that the electrical conduction properties of these compounds can be understood on the basis that the intercalation of atomic and/or molecular species between the host graphite layers either raises or lowers the Fermi level (E{sub F)} in a graphitic band structure. This movement of E{sub F} is accomplished via a charge transfer of electrons from the intercalate layers to the graphitic layers (donor compounds), or vice versa (acceptor compounds). Furthermore, the band structure must be modified to take into account the layers of charge that occur as a result of the charge transfer. This charge layering introduces additional bands of states near E{sub F}, which are discussed. Charge-transfer also induces a perturbation of the graphitic normal mode frequencies which can be understood as the result of a contraction (acceptor compounds) or expansion (donor compounds) of the intralayer C-C bonds. Ab-initio calculations support this view and are in reasonable agreement with experimental data.

Eklund, P.C.

1992-08-24

111

Effects-driven chemical fractionation of heavy fuel oil to isolate compounds toxic to trout embryos.  

PubMed

Heavy fuel oil (HFO) spills account for approximately 60% of ship-source oil spills and are up to 50 times more toxic than medium and light crude oils. Heavy fuel oils contain elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and alkyl-PAHs, known to be toxic to fish; however, little direct characterization of HFO toxicity has been reported. An effects-driven chemical fractionation was conducted on HFO 7102 to separate compounds with similar chemical and physical properties, including toxicity, to isolate the groups of compounds most toxic to trout embryos. After each separation, toxicity tests directed the next phase of fractionation, and gas chromatography-mass spectrometry analysis correlated composition with toxicity, with a focus on PAHs. Low-temperature vacuum distillation permitted the separation of HFO into 3 fractions based on boiling point ranges. The most toxic of these fractions underwent wax precipitation to remove long-chain n-alkanes. The remaining PAH-rich extract was further separated using open column chromatography, which provided distinct fractions that were grouped according to increasing aromatic ring count. The most toxic of these fractions was richest in PAHs and alkyl-PAHs. The results of the present study were consistent with previous crude oil studies that identified PAH-rich fractions as the most toxic. PMID:24375845

Bornstein, Jason M; Adams, Julie; Hollebone, Bruce; King, Thomas; Hodson, Peter V; Brown, R Stephen

2014-04-01

112

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

PubMed

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

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

2013-01-01

113

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...

114

Heteropteran chemical repellents identified in the citrus odor of a seabird (crested auklet: Aethia cristatella): evolutionary convergence in chemical ecology  

NASA Astrophysics Data System (ADS)

The exogenous application of chemical repellents is widespread in birds, but endogenous production is exceedingly rare. We herein report a new class of avian defensive compounds isolated from the feathers and volatile odor of the crested auklet ( Aethia cristatella). Mass spectra indicate that n-hexanal, n-octanal, n-decanal, Z-4-decenal and a 12-carbon unsaturated aldehyde comprise the auklet odorant. Octanal and hexanal are also secreted in the repugnant metasternal gland emissions of heteropteran insects and are known to be potent invertebrate repellents. We suggest that the auklet odorant functions as an ectoparasite repellent and a signal of mate quality. This would represent a rare and direct link between vigor, quality and parasite resistance, one of several putative bases for mate selection. This is the first report of defensive compounds produced by a seabird or colonial bird and one of the few examples of chemical defense in a polar or subpolar marine vertebrate.

Douglas, H. D.; Co, J. E.; Jones, T. H.; Conner, W. E.

2001-08-01

115

Heteropteran chemical repellents identified in the citrus odor of a seabird (crested auklet: Aethia cristatella ): evolutionary convergence in chemical ecology  

Microsoft Academic Search

The exogenous application of chemical repellents is widespread in birds, but endogenous production is exceedingly rare. We herein report a new class of avian defensive compounds isolated from the feathers and volatile odor of the crested auklet (Aethia cristatella). Mass spectra indicate that n-hexanal, n-octanal, n-decanal, Z-4-decenal and a 12-carbon unsaturated aldehyde comprise the auklet odorant. Octanal and hexanal are

H. D. Douglas; J. E. Co; T. H. Jones; W. E. Conner

2001-01-01

116

Chemical weapons: documented use and compounds on the horizon.  

PubMed

Man's inhumanity to man is expressed through a plethora of tools of modern warfare and terror. The use of chemical and biological weapons with the goals of assault, demoralisation and lethality has been documented in recent history, both on the battlefield and in urban terror against civilians. A general review of a few of the currently employed chemical weapons and biological toxins, along with a look at potential chemical weapons and tools of counter-terrorism, follows. While these weapons are fearsome elements, the dangers should be viewed in the context of the widespread availability and efficacy of conventional weapons. PMID:15093243

Bismuth, Chantal; Borron, Stephen W; Baud, Frederic J; Barriot, Patrick

2004-04-01

117

Chemical Profiles and Identification of Key Compound Caffeine in Marine-Derived Traditional Chinese Medicine Ostreae concha  

PubMed Central

To compare the chemical differences between the medicinal and cultured oyster shells, their chemical profiles were investigated. Using the ultra performance liquid chromatography-electron spraying ionization-mass spectrometry (UPLC-ESI-MS), combined with principal component analysis (PCA) and orthogonal projection to latent structures discriminant analysis (OPLS-DA), the discrimination of the chemical characteristics among the medicinal and cultured oyster shells was established. Moreover, the chemometric analysis revealed some potential key compounds. After a large-scale extraction and isolation, one target key compound was unambiguously identified as caffeine (1) based on extensive spectroscopic data analysis (1D and 2D NMR, MS, and UV) and comparison with literature data. PMID:22822365

Yang, Xue; Zhou, Shi-Lu; Ma, Ai-Cui; Xu, Hai-Tao; Guan, Hua-Shi; Liu, Hong-Bing

2012-01-01

118

Quantum chemical calculations for polymers and organic compounds  

NASA Technical Reports Server (NTRS)

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.

Lopez, J.; Yang, C.

1982-01-01

119

STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS  

PubMed Central

Sensitization of guinea pigs to picric acid was obtained by application of oil solutions to the skin, preferably on inflamed sites or by treatment with a compound of picric acid with n-butyl-p-aminobenzoate. The lesions obtained in sensitive animals on superficial administration bore resemblance to human eczema. It seems probable that picric acid sensitization is an instance where a substance does not sensitize directly but after conversion into a more reactive compound, a principle which should be of wider application to instances where the original substance does not readily form conjugates. PMID:19871030

Landsteiner, K.; Di Somma, A. A.

1940-01-01

120

The adsorption of selected chemical compounds on soil clays  

E-print Network

compounds by clays. Gieseking (15) published some of the first work on the ad- sorption of organic compounds by clays in 1939, but this phase of soil chemistry and physics has been slow to develop for several reasons. Some of the more apparent ones.... Another important aspect of the study might be the possi- bility of revealing new leads concerning the mechanism of ad- sorption of the larger organic molecules. If the more recent work conducted on clay lattice spacing by Grubbs (19) and Foster et al...

Hoover, William Leroy

2012-06-07

121

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

PubMed Central

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

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

2014-01-01

122

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...

123

EVALUATION USING AN ORGANOPHILIC CLAY TO CHEMICALLY STABILIZE WASTE CONTAINING ORGANIC COMPOUNDS  

EPA Science Inventory

A modified clay (organophilic) was utilized to evaluate the potential for chemically stabilizing a waste containing organic compounds. hemical bonding between the binder and the contaminants was indicated. eachate testing also indicated strong binding. Copy available at NTIS as ...

124

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

US Patent & Trademark Office Database

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.

2014-09-30

125

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 ...

126

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

SciTech Connect

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.

Fischer, L.; Deppert, W.R. [Department of Obstetrics and Gynecology, University Hospital Freiburg (Germany)] [Department of Obstetrics and Gynecology, University Hospital Freiburg (Germany); Pfeifer, D. [Department of Hematology and Oncology, University Hospital Freiburg (Germany)] [Department of Hematology and Oncology, University Hospital Freiburg (Germany); Stanzel, S.; Weimer, M. [Department of Biostatistics, German Cancer Research Center, Heidelberg (Germany)] [Department of Biostatistics, German Cancer Research Center, Heidelberg (Germany); Hanjalic-Beck, A.; Stein, A.; Straßer, M.; Zahradnik, H.P. [Department of Obstetrics and Gynecology, University Hospital Freiburg (Germany)] [Department of Obstetrics and Gynecology, University Hospital Freiburg (Germany); Schaefer, W.R., E-mail: wolfgang.schaefer@uniklinik-freiburg.de [Department of Obstetrics and Gynecology, University Hospital Freiburg (Germany)

2012-05-01

127

[Small compounds libraries: a research tool for chemical biology].  

PubMed

Obtaining and screening collections of small molecules remain a challenge for biologists. Recent advances in analytical techniques and instrumentation now make screening possible in academia. The history of the creation of such public or commercial collections and their accessibility is related. It shows that there is interest for an academic laboratory involved in medicinal chemistry, chemogenomics or "chemical biology" to organize its own collection and make it available through existing networks such as the French National chimiothèque or the European partner network "European Infrastructure of open screening platforms for Chemical Biology" EU-OpenScreen under construction. PMID:23694724

Florent, Jean-Claude

2013-01-01

128

A chemical biology approach identified PI3K as a potential therapeutic target for neurofibromatosis type 2  

PubMed Central

Mutations in the merlin tumor suppressor gene cause Neurofibromatosis type 2 (NF2), which is a disease characterized by development of multiple benign tumors in the nervous system. The current standard of care for NF2 calls for surgical resection of the characteristic tumors, often with devastating neurological consequences. There are currently no approved non-surgical therapies for NF2. In an attempt to identify much needed targets and therapeutically active compounds for NF2 treatment, we employed a chemical biology approach using ultra-high-throughput screening. To support this goal, we created a merlin-null mouse Schwann cell (MSC) line to screen for compounds that selectively decrease their viability and proliferation. We optimized conditions for 384-well plate assays and executed a proof-of-concept screen of the Library of Pharmacologically Active Compounds. Further confirmatory and selectivity assays identified phosphatidylinositol 3-kinase (PI3K) as a potential NF2 drug target. Notably, loss of merlin function is associated with activation of the PI3K/Akt pathway in human schwannomas. We report that AS605240, a PI3K inhibitor, decreased merlin-null MSC viability in a dose-dependent manner without significantly decreasing viability of control Schwann cells. AS605240 exerted its action on merlin-null MSCs by promoting caspase-dependent apoptosis and inducing autophagy. Additional PI3K inhibitors tested also decreased viability of merlin-null MSCs in a dose-dependent manner. In summary, our chemical genomic screen and subsequent hit validation studies have identified PI3K as potential target for NF2 therapy. PMID:25360213

Petrilli, Alejandra M; Fuse, Marisa A; Donnan, Mathew S; Bott, Marga; Sparrow, Nicklaus A; Tondera, Daniel; Huffziger, Julia; Frenzel, Corina; Malany, C Siobhan; Echeverri, Christophe J; Smith, Layton; Fernandez-Valle, Cristina

2014-01-01

129

Investigating the Effect of Emetic Compounds on Chemotaxis in Dictyostelium Identifies a Non-Sentient Model for Bitter and Hot Tastant Research  

PubMed Central

Novel chemical entities (NCEs) may be investigated for emetic liability in a range of unpleasant experiments involving retching, vomiting or conditioned taste aversion/food avoidance in sentient animals. We have used a range of compounds with known emetic /aversive properties to examine the possibility of using the social amoeba, Dictyostelium discoideum, for research into identifying and understanding emetic liability, and hence reduce adverse animal experimentation in this area. Twenty eight emetic or taste aversive compounds were employed to investigate the acute (10 min) effect of compounds on Dictyostelium cell behaviour (shape, speed and direction of movement) in a shallow chemotaxic gradient (Dunn chamber). Compound concentrations were chosen based on those previously reported to be emetic or aversive in in vivo studies and results were recorded and quantified by automated image analysis. Dictyostelium cell motility was rapidly and strongly inhibited by four structurally distinct tastants (three bitter tasting compounds - denatonium benzoate, quinine hydrochloride, phenylthiourea, and the pungent constituent of chilli peppers - capsaicin). In addition, stomach irritants (copper chloride and copper sulphate), and a phosphodiesterase IV inhibitor also rapidly blocked movement. A concentration-dependant relationship was established for five of these compounds, showing potency of inhibition as capsaicin (IC50?=?11.9±4.0 µM) > quinine hydrochloride (IC50?=?44.3±6.8 µM) > denatonium benzoate (IC50?=?129±4 µM) > phenylthiourea (IC50?=?366±5 µM) > copper sulphate (IC50?=?1433±3 µM). In contrast, 21 compounds within the cytotoxic and receptor agonist/antagonist classes did not affect cell behaviour. Further analysis of bitter and pungent compounds showed that the effect on cell behaviour was reversible and not cytotoxic, suggesting an uncharacterised molecular mechanism of action for these compounds. These results therefore demonstrate that Dictyostelium has potential as a non-sentient model in the analysis of the molecular effects of tastants, although it has limited utility in identification of emetic agents in general. PMID:21931717

Robery, Steven; Mukanowa, Janina; Percie du Sert, Nathalie; Andrews, Paul L. R.; Williams, Robin S. B.

2011-01-01

130

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

PubMed

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

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

2014-10-01

131

ToxAlerts: A Web Server of Structural Alerts for Toxic Chemicals and Compounds with Potential Adverse Reactions  

PubMed Central

The article presents a Web-based platform for collecting and storing toxicological structural alerts from literature and for virtual screening of chemical libraries to flag potentially toxic chemicals and compounds that can cause adverse side effects. An alert is uniquely identified by a SMARTS template, a toxicological endpoint, and a publication where the alert was described. Additionally, the system allows storing complementary information such as name, comments, and mechanism of action, as well as other data. Most importantly, the platform can be easily used for fast virtual screening of large chemical datasets, focused libraries, or newly designed compounds against the toxicological alerts, providing a detailed profile of the chemicals grouped by structural alerts and endpoints. Such a facility can be used for decision making regarding whether a compound should be tested experimentally, validated with available QSAR models, or eliminated from consideration altogether. The alert-based screening can also be helpful for an easier interpretation of more complex QSAR models. The system is publicly accessible and tightly integrated with the Online Chemical Modeling Environment (OCHEM, http://ochem.eu). The system is open and expandable: any registered OCHEM user can introduce new alerts, browse, edit alerts introduced by other users, and virtually screen his/her data sets against all or selected alerts. The user sets being passed through the structural alerts can be used at OCHEM for other typical tasks: exporting in a wide variety of formats, development of QSAR models, additional filtering by other criteria, etc. The database already contains almost 600 structural alerts for such endpoints as mutagenicity, carcinogenicity, skin sensitization, compounds that undergo metabolic activation, and compounds that form reactive metabolites and, thus, can cause adverse reactions. The ToxAlerts platform is accessible on the Web at http://ochem.eu/alerts, and it is constantly growing. PMID:22876798

2012-01-01

132

VALIDATED METHODS FOR DEGRADING HAZARDOUS CHEMICALS: SOME HALOGENATED COMPOUNDS  

Microsoft Academic Search

Two techniques were investigated for degrading a number of halogenated compounds of commercial and research importance. Reductive dehalogenation with nickel-aluminum alloy in potassium hydroxide solution was used to degrade iodomethane, chloroacetic acid, trichloroacetic acid, 2-chloroethanol, 2-bromoethanol, 2-chloroethylamine, 2-bromoethylamine, 1-bromobutane, 1-iodobutane, 2-bromobutane, 2-iodobutane, 2-bromo-2-methylpropane, 2-iodo-2-methylpropane, 3-chloropyridine, fluorobenzene, chlorobenzene, bromobenzene, iodobenzene, 4-fluoroaniline, 2-chloroaniline, 3-chloroaniline, 4-chloroaniline, 4-fluoronitrobenzene, 2-chloronitrobenzene, 3-chloronitrobenzene, 4-chloronitrobenzene, benzyl chloride, benzyl

George Lunn; Erie B. Sansone

1991-01-01

133

Chemical pneumonitis due to exposure to bromine compounds  

SciTech Connect

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.

Kraut, A.; Lilis, R.

1988-07-01

134

Antimalarial efficacy of dynamic compound of plumbagin chemical constituent from Plumbago zeylanica Linn (Plumbaginaceae) against the malarial vector Anopheles stephensi Liston (Diptera: Culicidae).  

PubMed

In the present investigation, the effective root compound of plumbagin of Plumbago zeylanica (Plumbaginaceae) was evaluated for chemical constituent and antimalarial effect against the fourth instar larvae of Anopheles stephensi Liston (Diptera). In the chromatographic analyses of root compound with Rf value of 0.788 and NMR analyses also revealed that the effective compound contain naphthoquinone plumbagin were identified as the major chemical constituent. Larval mortality was observed after 3 h of exposure period. The plumbagin compound showed remarkable larvicidal activity against A. stephensi (LC50 32.65 and LC9072.27 ppm). Histopathological effects of compound was observed in the treated larvae. Based on the results, the plumbagin compound of P. zeylanica can be considered as a new source of natural larvicide for the control of malarial vector. PMID:25028206

Pradeepa, Venkatraman; Sathish-Narayanan, Subbiah; Kirubakaran, Suyambulingam Arunachalam; Senthil-Nathan, Sengottayan

2014-08-01

135

Hexyl decanoate, the first trail pheromone compound identified in a stingless bee, Trigona recursa.  

PubMed

Foragers of many species of stingless bees guide their nestmates to food sources by means of scent trails deposited on solid substrates between the food and the nest. The corresponding trail pheromones are generally believed to be produced in the mandibular glands, although definitive experimental proof has never been provided. We tested the trail following behavior of recruits of Trigona recursa in field experiments with artificial scent trails branching off from natural scent trails of this stingless bee. First-time recruits (newcomers) did not follow these trails when they were laid with pure solvent or mandibular gland extract. However, they did follow trails made with labial gland extract. Chemical analyses of labial gland secretions revealed that hexyl decanoate was the dominant component (72.4 +/- 1.9% of all volatiles). Newcomers were significantly attracted to artificial trails made with synthetic hexyl decanoate, demonstrating its key function in eliciting scent-following behavior. According to our experiments with T. recursa, the trail pheromone is produced in the labial glands and not in the mandibular glands. Hexyl decanoate is the first component of a trail pheromone identified and proved to be behaviorally active in stingless bees. PMID:16718558

Jarau, Stefan; Schulz, Claudia M; Hrncir, Michael; Francke, Wittko; Zucchi, Ronaldo; Barth, Friedrich G; Ayasse, Manfred

2006-07-01

136

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

PubMed

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

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

137

Inhibitors of the Sodium Potassium ATPase that Impair Herpes Simplex Virus Replication Identified via a Chemical Screening Approach  

PubMed Central

Small molecules can provide valuable tools to investigate virus biology. We developed a chemical screening approach to identify small molecule inhibitors of poorly understood, pre-early gene expression steps in herpes simplex virus infection, using green fluorescent protein fused to an early protein. Our assay identified ouabain, a cardiac glycoside. Ouabain reversibly decreased viral yield by 100-fold without affecting cellular metabolic activity in an overnight assay. The antiviral potencies of other cardiac glycosides correlated with their potencies against the known target of these compounds, the cellular sodium potassium ATPase. Ouabain had a reduced effect if added 8 hours post infection. It did not inhibit viral attachment or entry, but did reduce the expression of viral immediate early and early genes by at least 5 fold. Collectively, these results implicate a cellular target that was hitherto not considered important for a stage of HSV replication prior to viral gene expression. PMID:17544048

Dodson, Allen W.; Taylor, Travis J; Knipe, David M.; Coen, Donald M.

2007-01-01

138

Chemical biology of histone acetyltransferase natural compounds modulators.  

PubMed

Histone acetyltransferases (HATs) are a class of epigenetic enzymes crucial for chromatin restructuring and transcriptional regulation in eukaryotic cells, thus being a promising target for therapeutic development. Nonetheless, differently from histone deacetylases (HDACs) inhibitors, there is still paucity of small-molecule modulators of HAT activity. After a decline during past decade, natural products and their derivatives could be once again a valuable tool in the lead discovery process and meet such need of Novel Chemical Entities (NCEs). In this review, we will provide a comprehensive summary on the discovery of small-molecule HAT modulators from naturally occurring molecular scaffolds. PMID:21197572

Piaz, Fabrizio Dal; Vassallo, Antonio; Rubio, Osmany Cuesta; Castellano, Sabrina; Sbardella, Gianluca; De Tommasi, Nunziatina

2011-05-01

139

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

USGS Publications Warehouse

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.

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

2002-01-01

140

Identifying new small molecule anti-invasive compounds for glioma treatment  

PubMed Central

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

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

2013-01-01

141

Chemical Analysis of Water of the Anticolana Valley: Isolation of Humic Compounds  

Microsoft Academic Search

The purpose of this study was to identify and characterize humic compounds in Anticolana Valley (Fiuggi) water. The capacity of this class of compounds to mobilize metals from solid phases could have an important role in calculi solubilization. Humic compounds were isolated, purified and characterised by FTIR, 1H-NMR and 13C-NMR spectroscopy, thermogravimetry and elemental analysis. Only fulvic acids were found.

N. Calace; G. D’Ascenzo; S. De Angelis Curtis; M. Delfini; A. Fraioli; B. M. Petronio

1999-01-01

142

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...

143

Journal of Chromatography A, 1071 (2005) 263269 Computer language for identifying chemicals with comprehensive  

E-print Network

Journal of Chromatography A, 1071 (2005) 263­269 Computer language for identifying chemicals with comprehensive two-dimensional gas chromatography and mass spectrometry Stephen E. Reichenbacha,, Visweswara with comprehensive two-dimensional gas chromatography paired with mass spectrometry (GC�GC­MS) and presents computer

Reichenbach, Stephen E.

144

Organohelium compounds: structures, stabilities and chemical bonding analyses.  

PubMed

This paper deals with the possibility of forming short and relatively strong carbon-helium bonds in small typical organic molecules through substitution of one or several H atoms by He(+). A structural and energetics study (based on high-level calculations) of this unusual bonding, as well as a topological characterization of the resulting cations, is undertaken. Stable species generally requires substitution of about half of the hydrogen atoms for formation. Under these conditions, the number of such species appears to be potentially unlimited. "True" C-He bonds exhibit equilibrium distances ranging from 1.327 (C2H2He2(2+)) to 1.129 Å (He2CO(2+)). The energies of neutral He releasing range from approximately 5 kcal?mol(-1) [He2CO(2+), (Z)-C2H2He2(2+)] to 25 kcal?mol(-1) (C2HHe3(3+)), but remain most frequently around 10 kcal?mol(-1). However, most of He(+)-substituted hydrocarbons are metastable with respect to C-C cleavage, except derivatives of ethene. Atoms in molecules (AIM) and electron localization function (ELF) topological descriptors classify the C-He bond as a weak charge-shift interaction [S. Shaik, D. Danovich, B. Silvi, D. L. Lauvergnat, P. C. Hiberty, Chem. Eur. J. 2005, 11, 6358-6371] in agreement with a recent publication by Rzepa [S. H. Rzepa, Nat. Chem. 2010, 2, 390-393]. He2CO(2+) is the only investigated compound that presents a C-He bonding ELF basin, which indicates a non-negligible covalent contribution to the bond. Other modifications in the electronic structure, such as the breaking of the triple bond in ethyne derivatives or the loss of aromaticity in C6H3He3(3+), are also nicely revealed by the ELF topology. PMID:24488791

Fourré, Isabelle; Alvarez, Elsa; Chaquin, Patrick

2014-02-24

145

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

PubMed Central

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

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

2014-01-01

146

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

PubMed

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

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

2014-01-01

147

Waterborne chemical compounds in tropical macroalgae: positive and negative cues for larval settlement  

Microsoft Academic Search

Settlement sites of marine invertebrate larvae are frequently influenced by positive or negative cues, many of which are chemical in nature. Following from the observation that many shallow-water, Hawai'ian marine macroalgae are free of fouling by sessile invertebrates, we predicted that the algae are chemically protected and dependent on either surface-bound or continuously released soluble compounds to deter settling invertebrate

L. J. Walters; M. G. Hadfield; C. M. Smith

1996-01-01

148

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

SciTech Connect

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.

Cone, M.V.; Baldauf, M.F.; Martin, F.M. (comps.) [comps.

1981-12-01

149

Chemical loss of volatile organic compounds and its impact on the source analysis through a two-year continuous measurement  

NASA Astrophysics Data System (ADS)

Chemical loss of volatile organic compounds (VOCs) is more important than the observed VOCs, which is the real actor of the chemical process in the atmosphere. The chemical loss of VOCs might impact on the identification of VOCs sources in ambient. For this reason, VOCs with 56 species were continuously measured in the urban area of Shanghai from 2009 to 2010, and based on the measurement the chemical loss of VOCs was calculated. According to the result, the initial VOCs in Shanghai urban was (34.8 ± 20.7) ppbv, higher than the observed one by ?35%, including alkanes (?38%), aromatics (?36%), alkenes (?17%), and acetylene (?8%). The chemical reactivity of VOCs would be underestimated by ?60% if the chemical loss were ignored. The chemical loss of VOCs showed a good agreement with Ox (O3 + NO2). C7-C8 aromatics and C3-C5 alkenes contributed ?60% of consumed VOCs. Seven sources were identified and quantified from positive matrix factorization (PMF) analysis. Vehicular emissions were the largest anthropogenic source of VOCs in Shanghai urban, accounting for 27.6% of VOCs, followed by solvent usage (19.4%), chemical industry (13.2%), petrochemical industry (9.1%), and coal burning (?5%). The contribution of biogenic emissions to total VOCs was 5.8%. Besides the five local anthropogenic sources and one biogenic source, the regional transportation was identified as one important source, contributing about 20% of VOCs in Shanghai urban. Sources apportionment results from PMF analysis based on the initial VOCs showed some differences from those based on observed data and might be more appropriate to be applied into the formulation of air pollution control measures.

Wang, H. L.; Chen, C. H.; Wang, Q.; Huang, C.; Su, L. Y.; Huang, H. Y.; Lou, S. R.; Zhou, M.; Li, L.; Qiao, L. P.; Wang, Y. H.

2013-12-01

150

Chemical Waste Disposal-Chemicals Identified in Terrestrial and Aquatic Waste Disposal Processes: A Selected Bibliography with Abstracts 1964-1979.  

National Technical Information Service (NTIS)

Chemical Waste Disposal - Chemicals Identified in Terrestrial and Aquatic Waste Disposal Processes contains 150 bibliographic references to the published literature from 1964 to 1979. Each bibliographic listing contains a citation (in alphabetical order b...

J. G. Pruett, S. G. Winslow

1980-01-01

151

Support Vector Machines in the Prediction of Mutagenicity of Chemical Compounds  

E-print Network

and different chemical compounds as food colourings and preservatives, drugs, paints for clothes and ordinary is of high public concern because it has a close relationship with carcinogenicity and eventually reproductive toxicity [5]: most of the mutagenic substances are suspected carcinogenic substance in case a g

Gini, Giuseppina

152

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

SciTech Connect

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.

Zimmering, S.; Mason, J.M.; Valencia, R. (Brown Univ., Providence, RI (USA))

1989-01-01

153

A study of psoriasis and the healing property of a new chemical compound.  

PubMed

This paper discusses in brief stressing the modern scientific views as well as ancient Indian concept of it. A compound developed from the chemical reaction of Haritala (Orpiment), Parada (Mercury) and Palasha Bhasma (white ash of Butea Monosperma) was evaluated here and observed to have market psoriasis healing property. PMID:22557618

Mahapatra, P R

1988-01-01

154

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

E-print Network

) An introduction to global fresh water issues. In: Gleick PH (ed.) Water in Crisis: A Guide to the World's Fresh some societies to subsist in semiarid and arid areas where other sources of fresh water (e.g., riversPercolated water can leach undesirable chemical compounds below the rooting zone of plants

155

A STUDY OF PSORIASIS AND THE HEALING PROPERTY OF A NEW CHEMICAL COMPOUND  

E-print Network

ABSTRACT: This paper discusses in brief stressing the modern scientific views as well as ancient Indian concept of it. A compound developed from the chemical reaction of Haritala (Orpiment), Parada (Mercury) and Palasha Bhasma (white ash of Butea Monosperma) was evaluated here and observed to have market psoriasis healing property.

P R. Mahapatra

1986-01-01

156

Chemical ecology and origin of defensive compounds in the Antarctic nudibranch Austrodoris kerguelenensis (Opisthobranchia: Gastropoda)  

Microsoft Academic Search

The common Antarctic nudibranch Austrodoris kerguelenensis (Bergh) contains diterpene diacylglycerides only present in its external body parts. These compounds provide a chemical defense against sympatric predators, such as the seastar Odontaster validus Koehler. Bioassays conducted with O. validus revealed that live nudibranchs, mantle tissue and Et2O extract of the A. kerguelenensis mantle deterred feeding by the seastar. Further bioassays testing

K. Iken; C. Avila; A. Fontana; M. Gavagnin

2002-01-01

157

Combustion chemical kinetics of biodiesel and related compounds (methyl and ethyl esters): Experiments and  

E-print Network

1 Combustion chemical kinetics of biodiesel and related compounds (methyl and ethyl esters transportation fuel dedicated to the diesel engine, biodiesel, with an emphasis on ethyl esters because of biodiesel and related components, the main gaps in the field are highlighted to facilitate the convergence

Paris-Sud XI, Université de

158

The Limits of Two-Year Bioassay Exposure Regimens for Identifying Chemical Carcinogens  

PubMed Central

Background Chemical carcinogenesis bioassays in animals have long been recognized and accepted as valid predictors of potential cancer hazards to humans. Most rodent bioassays begin several weeks after birth and expose animals to chemicals or other substances, including workplace and environmental pollutants, for 2 years. New findings indicate the need to extend the timing and duration of exposures used in the rodent bioassay. Objectives In this Commentary, we propose that the sensitivity of chemical carcinogenesis bio-assays would be enhanced by exposing rodents beginning in utero and continuing for 30 months (130 weeks) or until their natural deaths at up to about 3 years. Discussion Studies of three chemicals of different structures and uses—aspartame, cadmium, and toluene—suggest that exposing experimental animals in utero and continuing exposure for 30 months or until their natural deaths increase the sensitivity of bioassays, avoid false-negative results, and strengthen the value and validity of results for regulatory agencies. Conclusions Government agencies, drug companies, and the chemical industry should conduct and compare the results of 2-year bioassays of known carcinogens or chemicals for which there is equivocal evidence of carcinogenicity with longer-term studies, with and without in utero exposure. If studies longer than 2 years and/or with in utero exposure are found to better identify potential human carcinogens, then regulatory agencies should promptly revise their testing guidelines, which were established in the 1960s and early 1970s. Changing the timing and dosing of the animal bioassay would enhance protection of workers and consumers who are exposed to potentially dangerous workplace or home contaminants, pollutants, drugs, food additives, and other chemicals throughout their lives. PMID:19057693

Huff, James; Jacobson, Michael F.; Davis, Devra Lee

2008-01-01

159

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

PubMed Central

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

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

2014-01-01

160

Thin-layer chromatographic (TLC) separations and bioassays of plant extracts to identify antimicrobial compounds.  

PubMed

A common screen for plant antimicrobial compounds consists of separating plant extracts by paper or thin-layer chromatography (PC or TLC), exposing the chromatograms to microbial suspensions (e.g. fungi or bacteria in broth or agar), allowing time for the microbes to grow in a humid environment, and visualizing zones with no microbial growth. The effectiveness of this screening method, known as bioautography, depends on both the quality of the chromatographic separation and the care taken with microbial culture conditions. This paper describes standard protocols for TLC and contact bioautography with a novel application to amino acid-fermenting bacteria. The extract is separated on flexible (aluminum-backed) silica TLC plates, and bands are visualized under ultraviolet (UV) light. Zones are cut out and incubated face down onto agar inoculated with the test microorganism. Inhibitory bands are visualized by staining the agar plates with tetrazolium red. The method is applied to the separation of red clover (Trifolium pratense cv. Kenland) phenolic compounds and their screening for activity against Clostridium sticklandii, a hyper ammonia-producing bacterium (HAB) that is native to the bovine rumen. The TLC methods apply to many types of plant extracts and other bacterial species (aerobic or anaerobic), as well as fungi, can be used as test organisms if culture conditions are modified to fit the growth requirements of the species. PMID:24747583

Kagan, Isabelle A; Flythe, Michael D

2014-01-01

161

Unbiased probing of the entire hepatitis C virus life cycle identifies clinical compounds that target multiple aspects of the infection  

PubMed Central

Over 170 million people are chronically infected by the hepatitis C virus (HCV) and at risk for dying from liver cirrhosis and hepatocellular carcinoma. Current therapy is expensive, associated with significant side effects, and often ineffective. Discovery of antiviral compounds against HCV traditionally involves a priori target identification followed by biochemical screening and confirmation in cell-based replicon assays. Typically, this results in the discovery of compounds that address a few predetermined targets and are prone to select for escape variants. To attempt to identify antiviral compounds with broad target specificity, we developed an unbiased cell-based screening system involving multiple rounds of infection in a 96-well format. Analysis of a publicly available library of 446 clinically approved drugs identified 33 compounds that targeted both known and previously unexplored aspects of HCV infection, including entry, replication, and assembly. Discovery of novel viral and cellular targets in this manner will broaden the therapeutic armamentarium against this virus, allowing for the development of drug mixtures that should reduce the likelihood of mutational escape. PMID:19995961

Gastaminza, Pablo; Whitten-Bauer, Christina; Chisari, Francis V.

2009-01-01

162

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

PubMed Central

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

Vesell, E S; Passananti, G T

1977-01-01

163

Chemical analysis of water of the Anticolana Valley: isolation of humic compounds.  

PubMed

The purpose of this study was to identify and characterize humic compounds in Anticolana Valley (Fiuggi) water. The capacity of this class of compounds to mobilize metals from solid phases could have an important role in calculi solubilization. Humic compounds were isolated, purified and characterised by FTIR, 1H-NMR and 13C-NMR spectroscopy, thermogravimetry and elemental analysis. Only fulvic acids were found. They are mainly composed of aliphatic chains, made of six -CH2O- groups and contain a number of carboxylic groups, responsible for their metal complexing capacity. PMID:9873220

Calace, N; D'Ascenzo, G; De Angelis Curtis, S; Delfini, M; Fraioli, A; Petronio, B M

1999-01-01

164

High-Content Imaging Assays for Identifying Compounds that Generate Superoxide and Impair Mitochondrial Membrane Potential in Adherent Eukaryotic Cells.  

PubMed

Reactive oxygen species (ROS) are constantly produced in cells as a result of aerobic metabolism. When there is an excessive production of ROS and the cell's antioxidant defenses are overwhelmed, oxidative stress occurs. The superoxide anion is a type of ROS that is produced primarily in mitochondria but is also generated in other regions of the cell including peroxisomes, endoplasmic reticulum, plasma membrane, and cytosol. Here, a high-content imaging assay using the dye dihydroethidium is described for identifying compounds that generate superoxide in eukaryotic cells. A high-content imaging assay using the fluorescent dye tetramethylrhodamine methyl ester is also described to identify compounds that impair mitochondrial membrane potential in eukaryotic cells. The purpose of performing both assays is to identify compounds that (1) generate superoxide at lower concentrations than they impair mitochondrial membrane potential, (2) impair mitochondrial membrane potential at lower concentrations than they generate superoxide, (3) generate superoxide and impair mitochondrial function at similar concentrations, and (4) do not generate superoxide or impair mitochondrial membrane potential during the duration of the assays. Curr. Protoc. Toxicol. 59:25.1.1-25.1.14. © 2014 by John Wiley & Sons, Inc. PMID:24789364

Billis, Puja; Will, Yvonne; Nadanaciva, Sashi

2014-01-01

165

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

PubMed

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

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

2014-05-27

166

Volatile Organic Compounds Identified in Post-Flight Air Analysis of the Multipurpose Logistics Module from International Space Station  

NASA Astrophysics Data System (ADS)

Bioregenerative systems involve storing and processing waste along with atmospheric management. The MPLM, Multipurpose Logistics Module, is a reusable logistics carrier and primary delivery system used to resupply the International Space Station (ISS) and return Station cargo that requires a pressurized environment. The cylindrical module is approximately 6.4 meters long, 4.6 meters in diameter, and weighs almost 4,082kg. The module provides storage and additional workspace for up to two astronauts when docked to the ISS. It can carry up to 9,072 kg of supplies, science experiments, spare parts and other logistical components for ISS. There is concern for a potentially hazardous condition caused by contamination of the atmosphere in the MPLM upon return from orbit. This would be largely due to unforeseen spills or container leakage. This has led to the need for special care in handling the returned module prior to processing the module for its next flight. Prior to opening the MPLM, atmospheric samples are analyzed for trace volatile organic compounds, VOC's. It is noted that our analyses also reflect the atmosphere in the ISS on that day of closure. With the re turn of STS-108, 12th ISS Flight (UF1), the analysis showed 24 PPM of methane. This corresponds to the high levels on space station during a time period when the air filtration system was shut off. Chemical characterization of atmospheres on the ISS and MPLM provide useful information for concerns with plant growth experiments on ISS. Work with closed plant growth chambers show potential for VOC's to accumulate to toxic levels for plants. The ethylene levels for 4 MPLM analyses over the course on one year were measured at, 0.070, 0.017, 0.012 and 0.007 PPM. Phytochemical such as ethylene are detected with natural plant physiological events such as flowering and as a result of plant damage or from decaying food. A build up of VOC's may contribute to phytotoxic effects for the plant growth experiments or health problems for humans. Other identified components from the MPLM are quite similar to those found from off gassing of construction material and laboratory reagents characterized in ground based studies with closed plant growth chambers.

Peterson, B.; Wheeler, R.

167

Solving practical problems in environmental sampling for chemical agents and their degradation compounds  

SciTech Connect

The analyses of environmental samples for chemical agent degradation products were conducted using analytical test methods designed for evaluation of solid waste samples. All methods are found in the 3rd Edition of EPA`s compendium of analytical methods (SW-846) dated July 1992. These EPA methods are recommended for compliance testing required by the Resource Conservation and Recovery Act (RCRA) and are routinely used for the analysis of environmental samples. In the past several years, these same methods were used to support the survey of areas suspected of having chemical agent or chemical agent degradation compound contamination. An overview is presented of the U.S. Army Center for Health Promotion and Preventive Medicine`s (previously the U.S. Army Environmental Hygiene Agency) involvement with the analysis of samples for chemical agents and their degradation compounds collected from sites such as Tooele Army Depot, Rocky Mt. Arsenal, Newport Army Depot, Johnston Island, and Spring Valley, (a residential site near American University in Washington D.C.) Discussed are practical problems encountered during a quick response of a non-surety laboratory to analyze environmental samples for agents and their degradation compounds.

Williams, K.E.; Sheely, M.V. [Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, MD (United States)

1995-06-01

168

A bayesian analysis for identifying DNA copy number variations using a compound poisson process.  

PubMed

To study chromosomal aberrations that may lead to cancer formation or genetic diseases, the array-based Comparative Genomic Hybridization (aCGH) technique is often used for detecting DNA copy number variants (CNVs). Various methods have been developed for gaining CNVs information based on aCGH data. However, most of these methods make use of the log-intensity ratios in aCGH data without taking advantage of other information such as the DNA probe (e.g., biomarker) positions/distances contained in the data. Motivated by the specific features of aCGH data, we developed a novel method that takes into account the estimation of a change point or locus of the CNV in aCGH data with its associated biomarker position on the chromosome using a compound Poisson process. We used a Bayesian approach to derive the posterior probability for the estimation of the CNV locus. To detect loci of multiple CNVs in the data, a sliding window process combined with our derived Bayesian posterior probability was proposed. To evaluate the performance of the method in the estimation of the CNV locus, we first performed simulation studies. Finally, we applied our approach to real data from aCGH experiments, demonstrating its applicability. PMID:20976296

Chen, Jie; Yi?iter, Ayten; Wang, Yu-Ping; Deng, Hong-Wen

2010-01-01

169

Chemical bonding between uranium and oxygen in U 6+-containing compounds  

NASA Astrophysics Data System (ADS)

Electronic parameters of a suite of hexavalent uranium compounds measured with X-ray photoelectron spectroscopy (XPS) have been collected. The binding energy difference, ?BE = BE (O 1s) - BE (U 4f 7/2), was used to characterize the valence electron transfer on the formation of the U-O bonds. The chemical bonding effects were considered on the basis of published structural and XPS data for U 6+-bearing compounds. An empirical relationship is obtained between ?BE and the mean U-O bond distance, L(U-O).

Atuchin, Victor V.; Zhang, Zhaoming

2012-01-01

170

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

SciTech Connect

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.

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

1999-05-14

171

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

SciTech Connect

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.

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

1999-06-03

172

Laboratory Infrared Spectroscopy to Identify New Compounds on Icy Moon Surfaces  

NASA Astrophysics Data System (ADS)

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.

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

173

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

E-print Network

the chemicals · AniterativeBinary Search algorithm will significantly reduce the number of symptoms required needed to uniquely identify a chemical using MAIDN (mean=8.33, SD=0.7) compared to WISER (mean=25.69,SD · MethodtoEvaluatetheAlgorithm ­ Simulated a user diagnosing a chemical in both systems ­ Calculated

Bhavnani, Suresh K.

174

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

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

175

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

NASA Astrophysics Data System (ADS)

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.

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

2009-08-01

176

High-resolution transcriptional profiling of chemical-stimulated dendritic cells identifies immunogenic contact allergens, but not prohaptens.  

PubMed

Allergic contact dermatitis is a complex syndrome and knowledge about the in vitro detection of small-molecular-weight compounds, particularly prohaptens, is limited. Therefore, we investigated chemical-induced gene expression changes in human antigen-presenting cells upon stimulation with immunogenic contact allergens, prohaptens and irritants. Monocyte-derived dendritic cells (moDCs) and THP-1 cells were stimulated with the prohapten cinnamic alcohol (CAlc), the hapten cinnamic aldehyde (CAld), an irritant and an obligatory sensitizer in vitro. Whole-genome screening and consecutive PCR analysis of differential gene expression in moDCs stimulated with either CAld or the obligatory sensitizer revealed coregulation of 11 marker genes which were related to immunological reactions (IL-8, CD1e, CD200R1, PLA2G5, TNFRSF11A), oxidative or metabolic stress responses (AKR1C3, SLC7A11, GCLM) or other processes (DPYLS3, TFPI, TRIM16). In contrast, the prohapten CAlc and the irritant did not change marker gene expression. In THP-1 cells, CAld and the positive control elicited similar expression changes in only 4 of the previously identified genes (IL-8, TRIM16, CD200R1, GCLM). In conclusion, we provide important insights into the pathophysiological basis of allergic contact dermatitis, identify marker genes suitable for skin hazard assessment and demonstrate that contact-allergenic prohaptens escape in in vitro detection if their skin metabolism is not taken into account. PMID:20431333

Ott, H; Wiederholt, T; Bergström, M Andresen; Heise, R; Skazik, C; Czaja, K; Marquardt, Y; Karlberg, A-T; Merk, H-F; Baron, J M

2010-01-01

177

Conserved valproic-acid-induced lipid droplet formation in Dictyostelium and human hepatocytes identifies structurally active compounds  

PubMed Central

SUMMARY Lipid droplet formation and subsequent steatosis (the abnormal retention of lipids within a cell) has been reported to contribute to hepatotoxicity and is an adverse effect of many pharmacological agents including the antiepileptic drug valproic acid (VPA). In this study, we have developed a simple model system (Dictyostelium discoideum) to investigate the effects of VPA and related compounds in lipid droplet formation. In mammalian hepatocytes, VPA increases lipid droplet accumulation over a 24-hour period, giving rise to liver cell damage, and we show a similar effect in Dictyostelium following 30 minutes of VPA treatment. Using 3H-labelled polyunsaturated (arachidonic) or saturated (palmitic) fatty acids, we shown that VPA treatment of Dictyostelium gives rise to an increased accumulation of both types of fatty acids in phosphatidylcholine, phosphatidylethanolamine and non-polar lipids in this time period, with a similar trend observed in human hepatocytes (Huh7 cells) labelled with [3H]arachidonic acid. In addition, pharmacological inhibition of ?-oxidation in Dictyostelium phenocopies fatty acid accumulation, in agreement with data reported in mammalian systems. Using Dictyostelium, we then screened a range of VPA-related compounds to identify those with high and low lipid-accumulation potential, and validated these activities for effects on lipid droplet formation by using human hepatocytes. Structure-activity relationships for these VPA-related compounds suggest that lipid accumulation is independent of VPA-catalysed teratogenicity and inositol depletion. These results suggest that Dictyostelium could provide both a novel model system for the analysis of lipid droplet formation in human hepatocytes and a rapid method for identifying VPA-related compounds that show liver toxicology. PMID:22003123

Elphick, Lucy M.; Pawolleck, Nadine; Guschina, Irina A.; Chaieb, Leila; Eikel, Daniel; Nau, Heinz; Harwood, John L.; Plant, Nick J.; Williams, Robin S. B.

2012-01-01

178

Identifying Chemicals with Potential Therapy of HIV Based on Protein-Protein and Protein-Chemical Interaction Network  

PubMed Central

Acquired immune deficiency syndrome (AIDS) is a severe infectious disease that causes a large number of deaths every year. Traditional anti-AIDS drugs directly targeting the HIV-1 encoded enzymes including reverse transcriptase (RT), protease (PR) and integrase (IN) usually suffer from drug resistance after a period of treatment and serious side effects. In recent years, the emergence of numerous useful information of protein-protein interactions (PPI) in the HIV life cycle and related inhibitors makes PPI a new way for antiviral drug intervention. In this study, we identified 26 core human proteins involved in PPI between HIV-1 and host, that have great potential for HIV therapy. In addition, 280 chemicals that interact with three HIV drugs targeting human proteins can also interact with these 26 core proteins. All these indicate that our method as presented in this paper is quite promising. The method may become a useful tool, or at least plays a complementary role to the existing method, for identifying novel anti-HIV drugs. PMID:23762317

Chen, Lei; Wei, Ze-Jun; Huang, Tao; Jiang, Min; Lu, Jing; Zheng, Ming-Yue; Kong, Xiang-Yin; Cai, Yu-Dong

2013-01-01

179

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

PubMed

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

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

2010-04-01

180

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

DOEpatents

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.

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

1999-01-01

181

In Vivo Rapid Assessment of Compound Exposure (RACE) for Profiling the Pharmacokinetics of Novel Chemical Probes  

PubMed Central

The RACE assay is an easy and efficient method for estimating the exposure of novel chemical probe compounds in mice. RACE is a truncated and compressed version of a traditional comprehensive in vivo pharmacokinetics study. The method uses a single standard formulation, dose, route of administration, and a small cohort of mice (n=4). Standardized protocols and an abbreviated sample collection scheme reduce the labor needed to perform both the in life and bioanalytical phases of the study. The procedure reduces the complexity of data analysis by eliminating all but one calculated pharmacokinetic parameter; estimated exposure (eAUC20-120), a parameter that is sufficient to rank order compounds based on exposure, but is also easily determined by most software using the simple trapezoidal rule. The RACE assay protocol is readily applicable to early/exploratory studies of most compounds, and is intended to be employed by laboratories with limited expertise in pharmacology and pharmacokinetics. PMID:23788556

McAnally, Danielle; Vicchiarelli, Michael; Siddiquee, Khandaker

2013-01-01

182

Solid state chemical ionization for characterization of organic compounds by laser mass spectrometry.  

PubMed

A new technique involving the addition of a compound to the analyte to serve as a source of "reagent" ions has been developed for negative-ion laser mass spectrometry. This "solid state chemical ionization" leads to ions characteristic of the analyte, owing to ion-molecule reactions between the "reagent" ion and the neutral analyte in the laser-generated plume. Polycyclic aromatic hydrocarbons show formation of an ion corresponding to (M + O - H)(-) in their negative-ion laser mass spectra when mixed with compounds such as sym-trinitrobenzene, sodium nitrate and sodium peroxide. NO(-)(2), O(-), and O(-)(2) serve as "reagent" ions in these compounds. Formation of (M + Cl)(-) is seen in the laser mass spectra of glycosides mixed with hexachlorobenzene. Chloride serves as the "reagent" ion in this case. PMID:18964680

Balasanmugam, K; Viswanadham, S K; Hercules, D M

1989-01-01

183

Disputable issues in interpreting the results of chemical extraction of iron compounds from soils  

NASA Astrophysics Data System (ADS)

In Russia, iron is chemically fractionated according to a parallel scheme. Pyrophosphate-soluble iron (Fepyr) is considered to participate in organomineral complexes, oxalate-soluble iron (Feox) is believed to enter amorphous + poorly crystallized compounds, and dithionite-soluble iron (Fedit) is meant to represent the free (nonsilicate) compounds. However, the investigations prove that the commonly used subtraction operations (Feox - Fepyr) and (Fedit - Feox) are invalid because of the nonadditive action of the reagents in the parallel scheme of extraction. The low selectivity of reagents requires a new interpretation of chemically extracted iron compounds. In automorphic soils, the content of oxalate-soluble iron should be interpreted as the amount of Fe(III) capable of complexing with organic ligands; in hydromorphic soils with a stagnant moisture regime, it should be interpreted as the amount of iron (III) capable of being reduced in a short time. The content of dithionite-soluble compounds should be regarded as the amount of iron (III) within both (hydr)oxides and silicates potentially prone to reduction.

Vodyanitskii, Yu. N.; Shoba, S. A.

2014-06-01

184

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

SciTech Connect

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.

Yoshida, M.; Sunaga, M.; Hara, I. (Kansai Medical Univ., Osaka (Japan))

1990-09-01

185

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

NASA Astrophysics Data System (ADS)

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.

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

2002-06-01

186

Identifying bacteria in human urine: current practice and the potential for rapid, near-patient diagnosis by sensing volatile organic compounds.  

PubMed

Urinary tract infection (UTI) represents a significant burden for the National Health Service. Extensive research has been directed towards rapid detection of UTI in the last thirty years. A wide range of microbiological and chemical techniques are now available to identify and quantify bacteria in urine. However, there is a clear and present need for near, rapid, sensitive, reliable analytical methods, preferably with low-running costs, that could allow early detection of UTI and other diseases in urine. Here we review the "state of the art" of current practice for the detection of bacteria in urine and describe the advantages of the recent "e-nose" technology as a potential tool for rapid, near-patient diagnosis of UTI, by sensing volatile organic compounds (VOCs). PMID:11758602

Guernion, N; Ratcliffe, N M; Spencer-Phillips, P T; Howe, R A

2001-10-01

187

Chemical Genomics Identifies Small-Molecule MCL1 Repressors and BCL-xL as a Predictor of MCL1 Dependency  

PubMed Central

Summary MCL1, which encodes the anti-apoptotic protein MCL1, is among the most frequently amplified genes in human cancer. A chemical genomic screen identified compounds, including anthracyclines, that decreased MCL1 expression. Genomic profiling indicated that those compounds were global transcriptional repressors that preferentially affect MCL1 due to its short mRNA half-life. Transcriptional repressors and MCL1 shRNAs induced apoptosis in the same cancer cell lines and could be rescued by physiological levels of ectopic MCL1 expression. Repression of MCL1 released the pro-apoptotic protein BAK from MCL1, and Bak deficiency conferred resistance to transcriptional repressors. A computational model, validated in vivo, indicated that high BCL-xL expression confers resistance to MCL1 repression, thereby identifying a patient selection strategy for the clinical development of MCL1 inhibitors. PMID:22516262

Wei, Guo; Margolin, Adam A.; Haery, Leila; Brown, Emily; Cucolo, Lisa; Julian, Bina; Shehata, Shyemaa; Kung, Andrew L.; Beroukhim, Rameen; Golub, Todd R.

2012-01-01

188

Gene Expression Profiling Identifies Important Genes Affected by R2 Compound Disrupting FAK and P53 Complex.  

PubMed

Focal Adhesion Kinase (FAK) is a non-receptor kinase that plays an important role in many cellular processes: adhesion, proliferation, invasion, angiogenesis, metastasis and survival. Recently, we have shown that Roslin 2 or R2 (1-benzyl-15,3,5,7-tetraazatricyclo[3.3.1.1~3,7~]decane) compound disrupts FAK and p53 proteins, activates p53 transcriptional activity, and blocks tumor growth. In this report we performed a microarray gene expression analysis of R2-treated HCT116 p53+/+ and p53-/- cells and detected 1484 genes that were significantly up- or down-regulated (p < 0.05) in HCT116 p53+/+ cells but not in p53-/- cells. Among up-regulated genes in HCT p53+/+ cells we detected critical p53 targets: Mdm-2, Noxa-1, and RIP1. Among down-regulated genes, Met, PLK2, KIF14, BIRC2 and other genes were identified. In addition, a combination of R2 compound with M13 compound that disrupts FAK and Mmd-2 complex or R2 and Nutlin-1 that disrupts Mdm-2 and p53 decreased clonogenicity of HCT116 p53+/+ colon cancer cells more significantly than each agent alone in a p53-dependent manner. Thus, the report detects gene expression profile in response to R2 treatment and demonstrates that the combination of drugs targeting FAK, Mdm-2, and p53 can be a novel therapy approach. PMID:24452144

Golubovskaya, Vita M; Ho, Baotran; Conroy, Jeffrey; Liu, Song; Wang, Dan; Cance, William G

2014-01-01

189

System and method for preconcentrating, identifying, and quantifying chemical and biological substances  

DOEpatents

A system and method for preconcentrating, identifying, and quantifying chemical and biological substances is disclosed. An input valve directs a first volume of a sample gas to a surface acoustic wave (SAW) device. The SAW device preconcentrates and detects a mass of a substance within the sample gas. An output valve receives a second volume of the sample gas containing the preconcentrated substance from the SAW device and directs the second volume to a gas chromatograph (GC). The GC identifies the preconcentrated substance within the sample gas. A shunt valve exhausts a volume of the sample gas equal to the first volume minus the second volume away from the SAW device and the GC. The method of the present invention includes the steps of opening an input valve for passing a first volume of a sample gas to a SAW device; preconcentrating and detecting a mass of a substance within the sample gas using the SAW device; opening an output valve for passing a second volume of the sample gas containing the preconcentrated substance to a gas chromatograph (GC); and then identifying the preconcentrated substance within the sample gas using the GC.

Yu, Conrad M. (Antioch, CA); Koo, Jackson C. (San Ramon, CA)

2000-01-01

190

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

DOEpatents

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.

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

1997-01-01

191

Neutron interrogation to identify chemical elements with an ion-tube neutron source (INS)  

SciTech Connect

A non-destructive analysis technique using a portable, electric ion-tube neutron source (INS) and gamma ray detector has been used to identify the key constituent elements in a number of sealed munitions, and from the elemental makeup, infer the types of agent within each. The high energy (14 MeV) and pulsed character of the neutron flux from an INS provide a method of measuring, quantitatively, the oxygen, carbon, and fluorine content of materials in closed containers, as well as the other constituents that can be measured with low-energy neutron probes. The broad range of elements that can be quantitatively measured with INS-based instruments provides a capability of verifying common munition fills; it provides the greatest specificity of any portable neutron-based technique for determining the full matrix of chemical elements in completely unrestricted sample scenarios. The specific capability of quantifying the carbon and oxygen content of materials should lead to a fast screening technique which, can discriminate very quickly between high-explosive and chemical agent-filled containers.

Alvarez, R.A.; Dougan, A.D.; Rowland, M.R.; Wang, T.F.

1994-04-07

192

A chemical screen identifies class a g-protein coupled receptors as regulators of cilia.  

PubMed

Normal cilia length and motility are critical for proper cellular function. Prior studies of the regulation of ciliary structure and length have primarily focused on the intraflagellar transport machinery and motor proteins required for ciliary assembly and disassembly. However, several mutants with abnormal length flagella highlight the importance of signaling proteins as well. In this study, an unbiased chemical screen was performed to uncover signaling pathways that are critical for ciliogenesis and length regulation using flagella of the green alga Chlamydomonas reinhardtii as a model. The annotated Sigma LOPAC1280 chemical library was screened for effects on flagellar length, motility, and severing as well as cell viability. Assay data were clustered to identify pathways regulating flagella. The most frequent target found to be involved in flagellar length regulation was the family of dopamine binding G-protein coupled receptors (GPCRs). In mammalian cells, cilium length could indeed be altered with expression of the dopamine D1 receptor. Our screen thus reveals signaling pathways that are potentially critical for ciliary formation, resorption, and length maintenance, which represent candidate targets for therapeutic intervention of disorders involving ciliary malformation and malfunction. PMID:22375814

Avasthi, Prachee; Marley, Aaron; Lin, Henry; Gregori-Puigjane, Elisabet; Shoichet, Brian K; von Zastrow, Mark; Marshall, Wallace F

2012-05-18

193

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

PubMed

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

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

194

Mapping Asian anthropogenic emissions of non-methane volatile organic compounds to multiple chemical mechanisms  

NASA Astrophysics Data System (ADS)

An accurate speciation mapping of non-methane volatile organic compounds (NMVOC) emissions has an important impact on the performance of chemical transport models (CTMs) in simulating ozone mixing ratios and secondary organic aerosols. In this work, we developed an improved speciation framework to generate model-ready anthropogenic Asian NMVOC emissions for various gas-phase chemical mechanisms commonly used in CTMs by using an explicit assignment approach and updated NMVOC profiles, based on the total NMVOC emissions in the INTEX-B Asian inventory for the year 2006. NMVOC profiles were selected and aggregated from a wide range of new measurements and the SPECIATE database. To reduce potential uncertainty from individual measurements, composite profiles were developed by grouping and averaging source profiles from the same category. The fractions of oxygenated volatile organic compounds (OVOC) were corrected during the compositing process for those profiles which used improper sampling and analyzing methods. Emissions of individual species were then lumped into species in different chemical mechanisms used in CTMs by applying mechanism-dependent species mapping tables, which overcomes the weakness of inaccurate mapping in previous studies. Gridded emissions for eight chemical mechanisms are developed at 30 min × 30 min resolution using various spatial proxies and are provided through the website: http://mic.greenresource.cn/intex-b2006. Emission estimates for individual NMVOC species differ between one and three orders of magnitude for some species when different sets of profiles are used, indicating that source profile is the most important source of uncertainties of individual species emissions. However, those differences are diminished in lumped species as a result of the lumping in the chemical mechanisms.

Li, M.; Zhang, Q.; Streets, D. G.; He, K. B.; Cheng, Y. F.; Emmons, L. K.; Huo, H.; Kang, S. C.; Lu, Z.; Shao, M.; Su, H.; Yu, X.; Zhang, Y.

2013-12-01

195

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

SciTech Connect

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.

Thornberg, S.M.; Mowry, C.D.; Keenan, M.R.; Bender, S.F.A. [Sandia National Labs., Albuquerque, NM (United States). Gas Analysis Lab.; Owen, T. [Intel Corp., Rio Rancho, NM (United States)

1997-04-01

196

Effect of chemical pretreatment on anaerobic biodegradation of refractory organic compounds  

SciTech Connect

The potential for using chemical oxidation to enhance anaerobic biodegradability and reduce toxicity of two model phenolic compounds (o-cresol and 2,4-DNP) was evaluated. Batch bioassays were performed on the model compounds and their oxidation samples to determine biodegradability and toxicity in batch methanogenic cultures. Ozone, hydrogen peroxide, and potassium permanganate were the three oxidants examined in this study. A dose of approximately 5 moles hydrogen peroxide, in the presence of a ferrous iron catalyst (Fenton's reagent), 7 moles permanganate, or 25 moles of ozone per mole of o-cresol was needed to significantly enhance anaerobic biodegradability of oxidation samples. Approximately 2.5-4.5 moles of hydrogen peroxide or 7 moles of ozone per mole of 2,4-DNP reduced methanogenic toxicity by 50%. 25 refs., 6 figs., 3 tabs.

Wang, Y.T. (Univ. of Kentucky, Lexington, KY (United States))

1992-08-01

197

Identifying and characterizing chemical skin sensitizers without animal testing: Colipa’s research and method development program  

Microsoft Academic Search

The sensitizing potential of chemicals is usually identified and characterized using one of the available animal test methods, such as the mouse local lymph node assay. Due to the increasing public and political concerns regarding the use of animals for the screening of new chemicals, the Colipa Skin Tolerance Task Force collaborates with and\\/or funds research groups to increase and

P. Aeby; T. Ashikaga; S. Bessou-Touya; A. Schepky; F. Gerberick; P. Kern; M. Marrec-Fairley; G. Maxwell; J.-M. Ovigne; H. Sakaguchi; K. Reisinger; M. Tailhardat; S. Martinozzi-Teissier; P. Winkler

2010-01-01

198

Chemical states of tritium in solid lithium compounds irradiated with neutrons  

Microsoft Academic Search

Chemical states of tritium existing in neutron-irradiated solid lithium compounds were analyzed using a radiometric method. Nearly 100% of tritium was found in the T+ state in LiOH, Li2O2 and Li3N, while the T– state predominated in LiH, Li7Pb2 and Li2C2. Tritium incorporated in Li2O, Li2S, LiF, LiCl, LiBr and LiI was distributed over the T+, T– and T0 states.

H. Kudo; K. Okuno; H. Sugai; Y. Nagame

1985-01-01

199

Chemical and metabolomic screens identify novel biomarkers and antidotes for cyanide exposure  

PubMed Central

Exposure to cyanide causes a spectrum of cardiac, neurological, and metabolic dysfunctions that can be fatal. Improved cyanide antidotes are needed, but the ideal biological pathways to target are not known. To understand better the metabolic effects of cyanide and to discover novel cyanide antidotes, we developed a zebrafish model of cyanide exposure and scaled it for high-throughput chemical screening. In a screen of 3120 small molecules, we discovered 4 novel antidotes that block cyanide toxicity. The most potent antidote was riboflavin. Metabolomic profiling of cyanide-treated zebrafish revealed changes in bile acid and purine metabolism, most notably by an increase in inosine levels. Riboflavin normalizes many of the cyanide-induced neurological and metabolic perturbations in zebrafish. The metabolic effects of cyanide observed in zebrafish were conserved in a rabbit model of cyanide toxicity. Further, humans treated with nitroprusside, a drug that releases nitric oxide and cyanide ions, display increased circulating bile acids and inosine. In summary, riboflavin may be a novel treatment for cyanide toxicity and prophylactic measure during nitroprusside treatment, inosine may serve as a biomarker of cyanide exposure, and metabolites in the bile acid and purine metabolism pathways may shed light on the pathways critical to reversing cyanide toxicity.—Nath, A. K., Roberts, L. D., Liu, Y., Mahon, S. B., Kim, S., Ryu, J. H., Werdich, A., Januzzi, J. L., Boss, G. R., Rockwood, G. A., MacRae, C. A., Brenner, M., Gerszten, R. E., Peterson, R. T. Chemical and metabolomic screens identify novel biomarkers and antidotes for cyanide exposure. PMID:23345455

Nath, Anjali K.; Roberts, Lee D.; Liu, Yan; Mahon, Sari B.; Kim, Sonia; Ryu, Justine H.; Werdich, Andreas; Januzzi, James L.; Boss, Gerry R.; Rockwood, Gary A.; MacRae, Calum A.; Brenner, Matthew; Gerszten, Robert E.; Peterson, Randall T.

2013-01-01

200

Chemical compounds of past soluble aerosols preserved in the NEEM and Dome Fuji ice cores  

NASA Astrophysics Data System (ADS)

We will present a study on chemical compounds of past soluble aerosols preserved in the NEEM and Dome Fuji (DF) ice cores. We have developed a new method, called the 'ice sublimation method', for detecting large amounts of aerosol particles in polar ice cores #1. The elemental components of detected single particles were measured by SEM-EDS, and then chemical compounds of each single particle are obtained such as insoluble dust, soluble sulfate salts, and soluble chloride salts. We have applied this sublimation method to the NEEM and DF ice cores in order to compare chemical compounds of past aerosols during Holocene and Last Glacial Maximum (LGM) in Arctic and Antarctic regions. The results showed that the primary soluble aerosols are sodium sulfate during Holocene #2, and sodium sulfate, calcium sulfate and sodium chloride during LGM #1 in the DF ice core. On the other hand, soluble aerosols in NEEM core is more chloride rich (less sulfate) than that of the DF core. The chloride rich aerosols in NEEM ice core indicate that sea salt in Arctic atmosphere is likely to survive against oxidation from nitric and sulfuric acid. During LGM in the NEEM core, there are many particles of 1) coexistence of dust, sulfate salt, and chloride salt, and of 2) calcium chloride. The coexistence is a result of both sulfate and chloride salts formation on/in dust by attached from hydrochloric and sulfuric acid. Calcium chloride is secondary aerosol, and is probably formed by chemical reaction in atmosphere of calcium carbonate and hydrochloric acid. Hydrochloric acid is also a reacted product from sea salt and strong acid (nitric and sulfuric acid). The existence of these particles implies that multiple chemical reactions occurred in the Arctic atmosphere during LGM. #1: Iizuka et al., 2009 Constituent elements of insoluble and non-volatile particles during the Last Glacial Maximum of the Dome Fuji ice core. J. Glaciol., 55, 552-562. #2: Iizuka et al., 2012 The rates of sea salt sulfatization in the atmosphere and surface snow of inland Antarctica. J. Geophys. Res. In press

Iizuka, Y.; Hansson, M.; Oyabu, I.; Karlin, T.; Goto-Azuma, K.

2012-04-01

201

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...

202

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

PubMed Central

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

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

2013-01-01

203

Chemical constituents and cytotoxic effect of the main compounds of Lythrum salicaria L.  

PubMed

Lythrum salicaria L. (Lythraceae), a herbaceous plant growing widely in Iran, has been well known for many centuries for its astringent and styptic properties. A phytochemical investigation of this plant, based on spectroscopic analysis, identified fourteen compounds: 5-hydroxypyrrolidin-2-one (1), umbelliferone-6-carboxylic acid (2), 3,3',4'-tri-O-methylellagic acid-4-O-beta-D-(2"-acetyl)-glucopyranoside (3), 3,3',4'-tri-O-methylellagic acid-4-O-beta-D-glucopyranoside (4), daucosterol (5), phytol (6), dodecanoic acid (7), oleanolic acid (8), 3,3',4'-tri-O-methylellagic acid (9), corosolic acid (10), beta-sitosterol (11), peucedanin (12), buntansin (13), and erythrodiol (14). All compounds, except for 8 and 11, have been isolated from L. salicaria for the first time. Cytotoxic activities of the compounds were examined against three cancerous cell lines, colon carcinoma (HT-29), leukemia (K-562), and breast ductal carcinoma (T47D), and Swiss mouse embryo fibroblast (NIH-3T3) cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and methotrexate as positive control. Compounds 5, 10, 11, and 14 were the most active against the HT-29 cell line with IC50 values of 192.7, 36.8, 38.2, and 12.8 microg/mL, respectively. Compounds 14, 11, 5, and 10 were 6.4, 2.8, 2.6, and 1.4 times, respectively, more selective than methotrexate. Compound 5 was the most active against the K-562 cell line (IC50 = 50.2 microg/mL), with a selectivity exceeding that of methotrexate 13.3 times. The results of the cytotoxic assay confirmed that growth and proliferation of the cancer cell lines are predominantly influenced by triterpene derivatives and sterols of this plant. PMID:24459770

Manayi, Azadeh; Saeidnia, Soodabeh; Ostad, Seyed Nasser; Hadjiakhoondi, Abbas; Ardekani, Mohammad Reza Shams; Vazirian, Mahdi; Akhtar, Yasmin; Khanavi, Mahnaz

2013-01-01

204

Big data in chemical toxicity research: the use of high-throughput screening assays to identify potential toxicants.  

PubMed

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

Zhu, Hao; Zhang, Jun; Kim, Marlene T; Boison, Abena; Sedykh, Alexander; Moran, Kimberlee

2014-10-20

205

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

NASA Astrophysics Data System (ADS)

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.

Mariya, Vasilevich

2013-04-01

206

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

PubMed Central

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

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

2014-01-01

207

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...

208

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

E-print Network

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

Florida, University of

209

Inhibitors of the sodium potassium ATPase that impair herpes simplex virus replication identified via a chemical screening approach  

E-print Network

Inhibitors of the sodium potassium ATPase that impair herpes simplex virus replication identified to identify small molecule inhibitors of poorly understood, pre-early gene expression steps in herpes simplex gene expression. © 2007 Elsevier Inc. All rights reserved. Keywords: Herpes simplex virus; Chemical

Knipe, David M.

210

Exome Sequencing Analysis Identifies Compound Heterozygous Mutation in ABCA4 in a Chinese Family with Stargardt Disease  

PubMed Central

Stargardt disease is the most common cause of juvenile macular dystrophy. Five subjects from a two-generation Chinese family with Stargardt disease are reported in this study. All family members underwent complete ophthalmologic examinations. Patients of the family initiated the disease during childhood, developing progressively impaired central vision and bilateral atrophic macular lesions in the retinal pigmental epithelium (RPE) that resembled a “beaten-bronze” appearance. Peripheral venous blood was obtained from all patients and their family members for genetic analysis. Exome sequencing was used to analyze the exome of two patients II1, II2. A total of 50709 variations shared by the two patients were subjected to several filtering steps against existing variation databases. Identified variations were verified in all family members by PCR and Sanger sequencing. Compound heterozygous variants p.Y808X and p.G607R of the ATP-binding cassette, sub-family A (ABC1), member 4 (ABCA4) gene, which encodes the ABCA4 protein, a member of the ATP-binding cassette (ABC) transport superfamily, were identified as causative mutations for Stargardt disease of this family. Our findings provide one novel ABCA4 mutation in Chinese patients with Stargardt disease. PMID:24632595

Chen, Hui; Huang, Lulin; Zhu, Xiong; Li, Youping; Wang, Zhili; Lin, He; Hao, Fang; Yang, Zhenglin; Wang, Liya; Zhu, Xianjun

2014-01-01

211

Visualizing excipient composition and homogeneity of Compound Liquorice Tablets by near-infrared chemical imaging  

NASA Astrophysics Data System (ADS)

This study demonstrated that near-infrared chemical imaging (NIR-CI) was a promising technology for visualizing the spatial distribution and homogeneity of Compound Liquorice Tablets. The starch distribution (indirectly, plant extraction) could be spatially determined using basic analysis of correlation between analytes (BACRA) method. The correlation coefficients between starch spectrum and spectrum of each sample were greater than 0.95. Depending on the accurate determination of starch distribution, a method to determine homogeneous distribution was proposed by histogram graph. The result demonstrated that starch distribution in sample 3 was relatively heterogeneous according to four statistical parameters. Furthermore, the agglomerates domain in each tablet was detected using score image layers of principal component analysis (PCA) method. Finally, a novel method named Standard Deviation of Macropixel Texture (SDMT) was introduced to detect agglomerates and heterogeneity based on binary image. Every binary image was divided into different sizes length of macropixel and the number of zero values in each macropixel was counted to calculate standard deviation. Additionally, a curve fitting graph was plotted on the relationship between standard deviation and the size length of macropixel. The result demonstrated the inter-tablet heterogeneity of both starch and total compounds distribution, simultaneously, the similarity of starch distribution and the inconsistency of total compounds distribution among intra-tablet were signified according to the value of slope and intercept parameters in the curve.

Wu, Zhisheng; Tao, Ou; Cheng, Wei; Yu, Lu; Shi, Xinyuan; Qiao, Yanjiang

2012-02-01

212

Determination of total N-nitroso compounds by chemical denitrosation using CuCl.  

PubMed

A method for the determination of total N-nitroso compounds (NOC) by chemical denitrosation and subsequent chemiluminescence detection of evolved NO is described. Denitrosation was accomplished with CuCl in HCl at 70 degrees C. The detection limit for N-nitrosoproline (NPRO) was 1 pmol. NO formation from NPRO was linear (R(2) = 0.999) from 4 pmol to 2 nmol. Among the possible interfering compounds tested, only S-nitroso compounds contribute any significant interference. This method had several advantages over other similar methods: (1) A commercially available one-piece reaction vessel and a NO analyzer with software were used. (2) NO release occurred rapidly and was easily measured and quantified. (3) Compared to HBr or HI, CuCl was more convenient to work with and safe. (4) CuCl was suitable for samples in aqueous and most organic solvents. The application of this method to food, personal care products, and human body fluids demonstrates its utility. PMID:15941300

Wang, Jia; Chan, W Geoffrey; Haut, Stephen A; Krauss, Marc R; Izac, Richard R; Hempfling, Walter P

2005-06-15

213

Chemical Separation of Actinides from High Level Radioactive Liquid Waste Using Diglycol-amide (DGA) Compounds  

SciTech Connect

An innovative chemical separation process for the treatment of high level radioactive liquid waste (HLW) has been developed in our laboratory. There are two main stages in this process, the stage for our task is to recover all actinide (An) ions together with lanthanides (Ln), another task is to separate TRU from Ln. The diglycol-amide (DGA) compounds employed in this stage have several advantages, (1) carbon, hydrogen, oxygen and nitrogen atoms in their structures and gasification by combustion, (2) easy synthesis, (3) neutral and tridentate ligands, and (4) strong extraction ability with An from HNO{sub 3}. DGA compounds with the different structures can be obtained by attachment of the different alkyl groups to amidic N atoms, i.e., N,N,N',N'-tetra-octyl-diglycol-amide (TODGA), N,N,N',N'-tetra-dodecyl-diglycol-amide (TDdDGA), N,N,N',N'-tetra-methyl-diglycol-amide (TMDGA) and N,N,N',N'-tetra-ethyl-di-glycol-amide (TEDGA). TODGA and TDdDGA can be dissolved in hydrocarbon diluents, on the other hand, TMDGA and TEDGA are water-soluble ligands. TODGA and TDdDGA are expected to use as an extractant and TMDGA and TEDGA can be used for the reverse-extraction of An. The utility of DGA compounds, which shows the different characters, is revealed and the flow-sheet based on the salt-free concept is exhibited in this paper. (authors)

Sasaki, Yuji; Kitatsuji, Yoshihiro; Sugo, Yumi; Asakura, Toshihide; Kimura, Takaumi [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

2007-07-01

214

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

SciTech Connect

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.

Kleinstreuer, N.C., E-mail: kleinstreuer.nicole@epa.gov [NCCT, US EPA, RTP, NC 27711 (United States); Smith, A.M.; West, P.R.; Conard, K.R.; Fontaine, B.R. [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States)] [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States); Weir-Hauptman, A.M. [Covance, Inc., Madison, WI 53704 (United States)] [Covance, Inc., Madison, WI 53704 (United States); Palmer, J.A. [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States)] [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States); Knudsen, T.B.; Dix, D.J. [NCCT, US EPA, RTP, NC 27711 (United States)] [NCCT, US EPA, RTP, NC 27711 (United States); Donley, E.L.R. [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States)] [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States); Cezar, G.G. [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States) [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States); University of Wisconsin-Madison, Madison, WI 53706 (United States)

2011-11-15

215

Quinones and aromatic chemical compounds in particulate matter induce mitochondrial dysfunction: implications for ultrafine particle toxicity.  

PubMed

Particulate pollutants cause adverse health effects through the generation of oxidative stress. A key question is whether these effects are mediated by the particles or their chemical compounds. In this article we show that aliphatic, aromatic, and polar organic compounds, fractionated from diesel exhaust particles (DEPs), exert differential toxic effects in RAW 264.7 cells. Cellular analyses showed that the quinone-enriched polar fraction was more potent than the polycyclic aromatic hydrocarbon (PAH)-enriched aromatic fraction in O2 .- generation, decrease of membrane potential (Delta-Psi m), loss of mitochondrial membrane mass, and induction of apoptosis. A major effect of the polar fraction was to promote cyclosporin A (CsA)-sensitive permeability transition pore (PTP) opening in isolated liver mitochondria. This opening effect is dependent on a direct effect on the PTP at low doses as well as on an effect on Delta-Psi m at high doses in calcium (Ca2+)-loaded mitochondria. The direct PTP effect was mimicked by redox-cycling DEP quinones. Although the aliphatic fraction failed to perturb mitochondrial function, the aromatic fraction increased the Ca2+ retention capacity at low doses and induced mitochondrial swelling and a decrease in Delta-Psi m at high doses. This swelling effect was mostly CsA insensitive and could be reproduced by a mixture of PAHs present in DEPs. These chemical effects on isolated mitochondria could be reproduced by intact DEPs as well as ambient ultrafine particles (UFPs). In contrast, commercial polystyrene nanoparticles failed to exert mitochondrial effects. These results suggest that DEP and UFP effects on the PTP and Delta-Psi m are mediated by adsorbed chemicals rather than the particles themselves. PMID:15471724

Xia, Tian; Korge, Paavo; Weiss, James N; Li, Ning; Venkatesen, M Indira; Sioutas, Constantinos; Nel, Andre

2004-10-01

216

Carbon 13 chemical shift tensors in aromatic compounds. 3. Phenanthrene and triphenylene  

SciTech Connect

Measurements of the principal values of the {sup 13}C chemical shift tensor are presented for the three carbons in triphenylene and for three different {alpha} carbons in phenanthrene. The measurements in triphenylene were made in natural abundance samples at room temperature, while the phenanthrene tensors were obtained from selectively labeled compounds (99% {sup 13}C) at low temperatures ({approx} 25 K). The principal values of the shift tensors were oriented in the molecular frame using ab initio LORG calculations. The steric compression at C{sub 4} in phenanthrene and in corresponding positions in triphenylene is manifested in sizable upfield shift in the {sigma} 33 component relative to the corresponding {sigma} 33 values at C{sub 1} and C{sub 9} in phenanthrene. The upfield shift in {sigma} 33 is mainly responsible for the well-known upfield shift of the isotropic chemical shifts of such sterically perturbed carbons. In phenanthrene c{sub 9} exhibits a unique {sigma} 22 value reflecting the greater localization of {pi}-electrons in the c{sub 9}-C{sub 10} bond. This localization of the {pi}-electrons at the C{sub 9}-C{sub 10} bond in the central ring of phenanthrene also corresponds with the most likely ordering of electrons described by the various Kekule structures in phenanthrene. The analysis of the {sup 13}C chemical shieldings of the bridgehead carbons in the triphenylene provides significant experimental information on bonding between rings in polycyclic aromatic compounds. 39 refs., 8 fig., 3 tab.

Soderquist, A.; Hughes, C.D.; Horton, W.J.; Facelli, J.C.; Grant, D.M. [Univ. of Utah, Salt Lake City, UT (United States)

1992-04-08

217

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 ...

218

Compound  

NASA Astrophysics Data System (ADS)

We have prepared Ce-doped polycrystalline AgSbTe2.01 compounds from high-purity elements by a melt-quench technique followed by spark plasma sintering, and their thermoelectric transport properties have been investigated in the temperature range of 300 K to 625 K. The actual concentration of Ce was much less than the initial composition, but roughly proportional to it. Small additions of Ce shifted the composition of the homogeneity range from the nearly ideal atomic ratio Ag:Sb:Te = 0.98:1.02:2.01 toward Sb rich (Ag poor), and led to the reemergence of Ag2Te impurity in AgSbTe2 compound. The Ce-doped samples possessed lower electrical conductivity compared with the undoped AgSbTe2.01 compound at room temperature, but the carrier mobility and effective mass were essentially constant, indicating intact band structure near the covalent band maximum upon Ce substitution for Sb. Due to the decrease of lattice vibration anharmonicity resulting from Ce substitution for Sb, the lattice conductivity of the Ce-doped samples was about 0.1 W m-1 K-1 higher than that of the AgSbTe2.01 sample, and the magnitude spanned the range from 0.30 W m-1 K-1 to 0.55 W m-1 K-1. A ZT of 1.20 was achieved at about 615 K for the AgSb0.99Ce0.01Te2.01 sample.

Du, B.; Li, H.; Tang, X.

2014-06-01

219

Determining the chemical activity of hydrophobic organic compounds in soil using polymer coated vials  

PubMed Central

Background In soils contaminated by hydrophobic organic compounds, the concentrations are less indicative of potential exposure and distribution than are the associated chemical activities, fugacities and freely dissolved concentrations. The latter can be measured by diffusive sampling into thin layers of polymer, as in, for example, solid phase micro-extraction. Such measurements require equilibrium partitioning of analytes into the polymer while ensuring that the sample is not depleted. We introduce the validation of these requirements based on parallel sampling into polymer layers of different thicknesses. Results Equilibrium sampling devices were made by coating glass vials internally with 3–12 ?m thick layers of polydimethylsiloxane (PDMS). These were filled with slurries of a polluted soil and gently agitated for 5 days. The concentrations of 7 polycyclic aromatic hydrocarbons (PAHs) in the PDMS were measured. Validation confirmed fulfilment of the equilibrium sampling requirements and high measurement precision. Finally, chemical activities of the PAHs in the soil were determined from their concentrations and activity coefficients in the PDMS. Conclusion PAHs' thermodynamic activities in a soil test material were determined via a method of uptake into PDMS. This can be used to assess chemical exposure and predict diffusion and partitioning processes. PMID:18460193

Reichenberg, Fredrik; Smedes, Foppe; Jonsson, Jan-Ake; Mayer, Philipp

2008-01-01

220

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

PubMed

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

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

2011-01-01

221

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...

222

Assessment of multi-chemical pollution in aquatic ecosystems using toxic units: compound prioritization, mixture characterization and relationships with biological descriptors.  

PubMed

Chemical pollution is typically characterized by exposure to multiple rather than to single or a limited number of compounds. Parent compounds, transformation products and other non-targeted compounds yield mixtures whose composition can only be partially identified by monitoring, while a substantial proportion remains unknown. In this context, risk assessment based on the application of additive ecotoxicity models, such as concentration addition (CA), is rendered somewhat misleading. Here, we show that ecotoxicity risk information can be better understood upon consideration of the probabilistic distribution of risk among the different compounds. Toxic units of the compounds identified in a sample fit a lognormal probability distribution. The parameters characterizing this distribution (mean and standard deviation) provide information which can be tentatively interpreted as a measure of the toxic load and its apportionment among the constituents in the mixture (here interpreted as mixture complexity). Furthermore, they provide information for compound prioritization tailored to each site and enable prediction of some of the functional and structural biological variables associated with the receiving ecosystem. The proposed approach was tested in the Llobregat River basin (NE Spain) using exposure and toxicity data (algae and Daphnia) corresponding to 29 pharmaceuticals and 22 pesticides, and 5 structural and functional biological descriptors related to benthic macroinvertebrates (diversity, biomass) and biofilm metrics (diatom quality, chlorophyll-a content and photosynthetic capacity). Aggregated toxic units based on Daphnia and algae bioassays provided a good indication of the pollution pattern of the Llobregat River basin. Relative contribution of pesticides and pharmaceuticals to total toxic load was variable and highly site dependent, the latter group tending to increase its contribution in urban areas. Contaminated sites' toxic load was typically dominated by fewer compounds as compared to cleaner sites where more compounds contribute. PMID:24070871

Ginebreda, Antoni; Kuzmanovic, Maja; Guasch, Helena; de Alda, Miren López; López-Doval, Julio C; Muñoz, Isabel; Ricart, Marta; Romaní, Anna M; Sabater, Sergi; Barceló, Damià

2014-01-15

223

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

SciTech Connect

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.

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

224

Chemical composition and antibacterial activity of selected essential oils and some of their main compounds.  

PubMed

The chemical composition of essential oils of cabreuva (Myrocarpus fastigiatus Allemao, Fabaceae) from Brazil, cedarwood (Juniperus ashei, Cupressaceae) from Texas, Juniper berries (Juniperus communis L., Cupressaceae) and myrrh (Commiphora myrrha (Nees) Engl., Burseraceae) were analyzed using GC/FID and GC/MS. The antimicrobial activity of these essential oils and some of their main compounds were tested against eleven different strains of Gram-positive and Gram-negative bacteria by using agar diffusion and agar serial dilution methods. Animal and plant pathogens, food poisoning and spoilage bacteria were selected. The volatile oils exhibited considerable inhibitory effects against all tested organisms, except Pseudomonas, using both test methods. Higher activity was observed against Gram-positive strains in comparison with Gram-negative bacteria. Cabreuva oil from Brazil showed similar results, but in comparison with the other oils tested, only when higher concentrations of oil were used. PMID:20922991

Wanner, Juergen; Schmidt, Erich; Bail, Stefanie; Jirovetz, Leopold; Buchbauer, Gerhard; Gochev, Velizar; Girova, Tanya; Atanasova, Teodora; Stoyanova, Albena

2010-09-01

225

Microencapsulation of a crop protection compound by initiated chemical vapor deposition.  

PubMed

In this work, initiated chemical vapor deposition (iCVD) has been employed as a one-step liquid-free process combining polymerization and coating for the encapsulation of 3D non-planar substrates. Coatings have been applied using iCVD specifically to encapsulate microparticles of a highly water-soluble crop protection compound (CPC) for controlled release. Release behavior has been compared among different coatings synthesized using different iCVD processing conditions, including varying degrees of polymer hydrophobicity, continuous and pulsed deposition, and crosslinking. iCVD has been found to provide tunable synthesis of hydrophobic, crosslinked polymers with control over mass diffusivity, and coating thickness for enhancing barrier properties. PMID:22573697

Bose, Ranjita K; Heming, Alex M; Lau, Kenneth K S

2012-08-28

226

Relations between the structure of storage and the transport of chemical compounds in karstic aquifers  

NASA Astrophysics Data System (ADS)

Study of the movement of chemical compounds naturally present in the water, or which result from pollution, are examined according to the reservoir structure in karstic aquifers. Structure is represented by a simple geometrical model; slow flow takes place in blocks with a network of low-permeability cracks. The blocks are separated by highly permeable karstic conduits that allow rapid flow, and these form the aquifer drainage system. The karst studied covers 110 km 2. It is fed by an interrupted stream draining a 35 km 2 non-karstic basin, contaminated at the entry to the karst by effluents from a sewage treatment station. The underground water reappears as a resurgence with an annual average flow of approximately 1 m 3 s -1, after an apparent underground course of 8 km in the karst. Several local sources of pollution (effluent from septic tanks) contaminate the underground water during its course. Sixteen measurement operations were performed at 12 water points, between the interrupted stream and the spring. Some sampling points were at drains, and others were in the low-permeability fissured blocks. Comparison at each point of the concentrations of 14 chemical compounds gave the following results: when pollutant discharge occurs in a permeable zone, movement is rapid in the drainage network formed by the karstic conduits, and does not reach the less permeable fissured blocks which are thus protected; however, if discharge is in a low-permeability zone, the flow does not allow rapid movement of the polluted water, and this increases the pollutant concentration at the discharge. This simple pattern can be upset by a reversal of the apparent piezometric gradient between a block and a conduit during floods or pumping; this may reverse flow directions and hence modify the movement of contaminants. The study made it possible to site five boreholes whose positions in the karstic structure were unknown, showing the interest of such an approach for the forecasting of the impact of potential pollution.

Vaute, L.; Drogue, C.; Garrelly, L.; Ghelfenstein, M.

1997-12-01

227

Effects of Chemical Speciation on the Mineralization of Organic Compounds by Microorganisms  

PubMed Central

The mineralization of 1.0 to 100 ng each of four complexing compounds—oxalate, citrate, nitrilotriacetate (NTA), and EDTA—per ml was tested in media prepared in accordance with equilibrium calculations by a computer program so that the H, Ca, Mg, Fe, or Al complex (chemical species) was predominant. Sewage microorganisms mineralized calcium citrate more rapidly than iron, aluminum, or hydrogen citrate, and magnesium citrate was degraded slowest. Aluminum, hydrogen, and iron oxalates were mineralized more rapidly than calcium oxalate, and magnesium oxalate was decomposed slowest. Sewage microorganisms mineralized calcium NTA but not aluminum, magnesium, hydrogen, or iron NTA or any of the EDTA complexes. Pseudomonas sp. mineralized calcium and iron citrates but had no activity on hydrogen, aluminum, or magnesium citrate. Pseudomonas pseudoalcaligenes mineralized calcium, iron, hydrogen, and aluminum citrates but had little activity on magnesium citrate. Pseudomonas alcaligenes used calcium, iron, hydrogen, and aluminum oxalates readily, but it used magnesium oxalate at a slower rate. Listeria sp. destroyed calcium NTA but had no effect on hydrogen, iron, or magnesium NTA. Increasing the Ca concentration in the medium enhanced the breakdown of NTA by Listeria sp. The different activities of the bacterial isolates were not a result of the toxicity of the complexes or the lack of availability of a nutrient element. NTA mineralization was not enhanced by the addition of Ca to Beebe Lake water, but it was enhanced when Ca and an NTA-degrading inoculum were added to water from an oligotrophic lake. The data show that chemical speciation influences the mineralization of organic compounds by naturally occurring microbial communities and by individual bacterial populations. PMID:16346854

Madsen, E. L.; Alexander, Martin

1985-01-01

228

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

229

Effect of five different stages of ripening on chemical compounds in medlar (Mespilus germanica L.).  

PubMed

The study of changes of nutritional value of fruit during the ripening process can help estimate the optimal date for fruit harvesting to achieve the best quality for direct consumption and further utilization. The aim of this study was to monitor the changes of chemical composition of medlar fruit (Mespilus germanica L.) measured at five various ripening stages including 134, 144, 154, 164 and 174 days after full bloom (DAFB). Fruits were analyzed and ascorbic acid (AA) and total phenolic compound content with respect to the total antioxidant activity were determined. In addition, selected micronutrients and macronutrients were monitored. The results of our experiments demonstrate that ascorbic acid, total phenolic compound content and total antioxidant activity decreased significantly with increasing time of ripeness. The decreasing tendency in potassium, calcium and magnesium contents during the ripening stages was also determined. During the ripening period, the content of all micronutrients as well as phosphorus and sodium was balanced, with no statistically significant differences between the monitored ripening stages, which can be considered as a positive fact with respect to ideal consumption quality of fruit. PMID:21189456

Rop, Otakar; Sochor, Jiri; Jurikova, Tunde; Zitka, Ondrej; Skutkova, Helena; Mlcek, Jiri; Salas, Petr; Krska, Boris; Babula, Petr; Adam, Vojtech; Kramarova, Daniela; Beklova, Miroslava; Provaznik, Ivo; Kizek, Rene

2011-01-01

230

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...

231

Chemical composition and major odor-active compounds of essential oil from PINELLIA TUBER (dried rhizome of Pinellia ternata) as crude drug.  

PubMed

The chemical composition of the essential oil from PINELLIA TUBER (Japanese name: Hange), the dried rhizome of Pinellia ternata, was investigated by capillary gas chromatography (GC) and GC-mass spectrometry (MS) analyses. The oil obtained from Pinellia tuber was revealed the presence of 114 compounds, representing 90.6% of the total oil identified. This colorless oil had a spicy and woody odor. The main components of the oil were ?-cubebene (8.8%), atractylon (7.8%), methyl eugenol (6.2%), and ?-cadinene (5.3%). Fifteen major odor-active compounds were identified in the essential oil from PINELLIA TUBER by the GC-olfactometry (GC-O) and aroma extract dilution analysis (AEDA). Among these, safrole (spicy) and ?-vatirenene (woody) showed the highest flavor dilution (FD) factor (128), followed by paeonol (FD = 64; woody, spicy), ?-humulene (FD = 64; woody), and ?-phenylnaphthalene (FD = 64; spicy). PMID:24500103

Iwasa, Megumi; Iwasaki, Toshiki; Ono, Toshirou; Miyazawa, Mitsuo

2014-01-01

232

compounds  

NASA Astrophysics Data System (ADS)

Size is the key factor of nanostructured materials, since all the structural, transport, electrical, magnetic and other physical properties can be tuned by this factor of materials. Only the condition is to choose appropriate inexpensive scale-processing method for material synthesis which offers good control over the stoichiometry, morphology and particle size distribution. Present communication deals with the studies on the sol-gel grown Y0.95Ca0.05MnO3 (YCMO) nanostructured compounds for their size-induced tuning of dielectric behavior. Structural studies reveal the single phasic nature with improved crystallite size with sintering temperature. Dielectric constant (real and imaginary) is found to increase with temperature and crystallite size/sintering temperature. High dielectric loss has been observed in the present system. Size dependent activation energy ( E a), obtained from modulus measurement, showing the increase in E a with crystallite size. The variation in various dielectric parameters and E a has been discussed in the light of crystallite size, crystallite boundaries, oxygen vacancies and charge carrier hopping.

Shah, N. A.

2014-10-01

233

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 ...

234

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

NASA Astrophysics Data System (ADS)

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.

Apel, E. C.; Emmons, L. K.; Karl, T.; 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.; Ortega, J.; Voss, P.; Blake, D.; Baker, A.; Warneke, C.; Welsh-Bon, D.; de Gouw, J.; Zheng, J.; Zhang, R.; Rudolph, J.; Junkermann, W.; Riemer, D. D.

2009-11-01

235

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

NASA Astrophysics Data System (ADS)

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 approximate the observed MCMA daytime patterns and absolute values of the VOC OH reactivity. The MOZART model is also in agreement with observations showing that NMHCs dominate the reactivity distribution except in the afternoon hours. 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. A northeast transport event was studied in which air originating in the MCMA was intercepted aloft with the Department of Energy (DOE) G1 on 18 March and downwind with the National Center for Atmospheric Research (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 was shown to be photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial extent and temporal evolution of the plume and to help interpret the observed OH reactivity. 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. 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.

Apel, E. C.; Emmons, L. K.; Karl, T.; Flocke, F.; Hills, A. J.; Madronich, S.; Lee-Taylor, J.; Fried, A.; Weibring, P.; Walega, J.; Richter, D.; Tie, X.; Mauldin, L.; Campos, T.; Weinheimer, A.; Knapp, D.; Sive, B.; Kleinman, L.; Springston, S.; Zaveri, R.; Ortega, J.; Voss, P.; Blake, D.; Baker, A.; Warneke, C.; Welsh-Bon, D.; de Gouw, J.; Zheng, J.; Zhang, R.; Rudolph, J.; Junkermann, W.; Riemer, D. D.

2010-03-01

236

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

SciTech Connect

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.

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

237

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

SciTech Connect

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.

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

2000-10-01

238

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

ERIC Educational Resources Information Center

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)

Bretherick, Leslie

1989-01-01

239

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...

240

Steps in the Development of Chemical and Electrical Synapses by Pairs of Identified Leech Neurons in Culture  

Microsoft Academic Search

Experiments have been made to follow the development of chemical and electrical transmission between pairs of leech neurons in culture. 1 The cell bodies of identified neurons were isolated from the CNS by suction after mild enzyme treatment. together with a length of the initial segment (or `stump'). The neurons tested were Retzius cells (R), annulus erector motoneurons (AE). Anterior

Y. Liu; J. Nicholls

1989-01-01

241

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

USGS Publications Warehouse

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.

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

1988-01-01

242

IDENTIFYING INDICATORS OF REACTIVITY FOR CHEMICAL REDUCTANTS IN ANOXIC AND ANAEROBIC SEDIMENTS  

EPA Science Inventory

To develop reaction transport models describing the movement of redox-active organic contaminants through contaminated sediments and aquifers, it is imperative to know the identity and reactivity of chemical reductants in natural sediments and to associate their reactivity with p...

243

Remote Continuous Wave and Pulsed Laser Raman Detection of Chemical Warfare Agents Simulants and Toxic Industrial Compounds  

Microsoft Academic Search

This study describes the design, assembly, testing and comparison of two Remote Raman Spectroscopy (RRS) systems intended\\u000a for standoff detection of hazardous chemical liquids. Raman spectra of Chemical Warfare Agents Simulants (CWAS) and Toxic\\u000a Industrial Compounds (TIC) were measured in the laboratory at a 6.6 m source-target distance using continuous wave (CW) laser\\u000a detection. Standoff distances for pulsed measurements were 35 m

William Ortiz-Rivera; Leonardo C. Pacheco-Londoño; Samuel P. Hernández-Rivera

2010-01-01

244

Identifying unknown minerals and compounds from X-ray diffraction patterns using the Johnson and Vand FORTRAN 4 computer program  

NASA Technical Reports Server (NTRS)

Automated computer identification of minerals and compounds from unknown samples is provided along with detailed instructions and worked examples for use in graduate level courses in mineralogy and X-ray analysis applications.

Kyte, F. T.

1976-01-01

245

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

246

Small Fish Models for Identifying and Assessing the Effects of Endocrine-disrupting Chemicals  

Microsoft Academic Search

Endocrine-disrupting chemicals (EDCs), particularly those that affect the hypothalamic-pituitary-gonadal (HPG) axis of vertebrates, have become a focus of regulatory screening and testing throughout the world. Small fish species, prin- cipally the fathead minnow (Pimephales promelas), Japa- nese medaka (Oryzias latipes), and zebrafish (Danio rerio), are used as model organisms for several of these testing programs. Fish are appropriate models for

Gerald T. Ankley; Rodney D. Johnson

2004-01-01

247

Screening with a Novel Cell-Based Assay for TAZ Activators Identifies a Compound That Enhances Myogenesis in C2C12 Cells and Facilitates Muscle Repair in a Muscle Injury Model  

PubMed Central

The transcriptional coactivator with a PDZ-binding motif (TAZ) cooperates with various transcriptional factors and plays various roles. Immortalized human mammalian epithelial MCF10A cells form spheres when TAZ is overexpressed and activated. We developed a cell-based assay using sphere formation by TAZ-expressing MCF10A cells as a readout to screen 18,458 chemical compounds for TAZ activators. Fifty compounds were obtained, and 47 were confirmed to activate the TAZ-dependent TEAD-responsive reporter activity in HEK293 cells. We used the derived subset of compounds as a TAZ activator candidate minilibrary and searched for compounds that promote myogenesis in mouse C2C12 myoblast cells. In this study, we focused on one compound, IBS008738. IBS008738 stabilizes TAZ, increases the unphosphorylated TAZ level, enhances the association of MyoD with the myogenin promoter, upregulates MyoD-dependent gene transcription, and competes with myostatin in C2C12 cells. TAZ knockdown verifies that the effect of IBS008738 depends on endogenous TAZ in C2C12 cells. IBS008738 facilitates muscle repair in cardiotoxin-induced muscle injury and prevents dexamethasone-induced muscle atrophy. Thus, this cell-based assay is useful to identify TAZ activators with a variety of cellular outputs. Our findings also support the idea that TAZ is a potential therapeutic target for muscle atrophy. PMID:24550007

Yang, Zeyu; Nakagawa, Kentaro; Sarkar, Aradhan; Maruyama, Junichi; Iwasa, Hiroaki; Bao, Yijun; Ishigami-Yuasa, Mari; Ito, Shigeru; Kagechika, Hiroyuki; Hata, Shoji; Nishina, Hiroshi; Abe, Shinya; Kitagawa, Masanobu

2014-01-01

248

Gas chromatography-atmospheric pressure chemical ionization-time of flight mass spectrometry for profiling of phenolic compounds in extra virgin olive oil.  

PubMed

A new analytical approach based on gas chromatography coupled to atmospheric pressure chemical ionization-time of flight mass spectrometry was evaluated for its applicability for the analysis of phenolic compounds from extra-virgin olive oil. Both chromatographic and MS parameters were optimized in order to improve the sensitivity and to maximize the number of phenolic compounds detected. We performed a complete analytical validation of the method with respect to its linearity, sensitivity, precision, accuracy and possible matrix effects. The LODs ranged from 0.13 to 1.05ppm for the different tested compounds depending on their properties. The RSDs for repeatability test did not exceed 6.07% and the accuracy ranged from 95.4% to 101.5%. To demonstrate the feasibility of our method for analysis of real samples, we analyzed the extracts of three different commercial extra-virgin olive oils. We have identified unequivocally a number of phenolic compounds and obtained quantitative information for 21 of them. In general, our results show that GC-APCI-TOF MS is a flexible platform which can be considered as an interesting tool for screening, structural assignment and quantitative determination of phenolic compounds from virgin olive oil. PMID:21241992

García-Villalba, Rocío; Pacchiarotta, Tiziana; Carrasco-Pancorbo, Alegría; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto; Deelder, André M; Mayboroda, Oleg A

2011-02-18

249

Overview of Toxicity Data and Risk Assessment Methods for Evaluating the Chemical Effects of Depleted Uranium Compounds  

Microsoft Academic Search

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

Heidi M. Hartmann; Frederick A. Monette; Halil I. Avci

2000-01-01

250

Determination of chemical classes from mass spectra of toxic organic compounds by SIMCA pattern recognition and information theory  

Microsoft Academic Search

The low-resolution mass spectra of a set of 78 toxic volatile organic compounds were examined for information concerning chemical classes. The Shannon information content for each mass channel was calculated for the binary encoded and the full intensity spectra, using 1% of the base peak as the threshold level. The 17 masses with the highest binary information content were retained

Donald R. Scott

1986-01-01

251

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

PubMed Central

Chemical cross-linking combined with mass spectrometry provides a powerful method for identifying protein-protein interactions and probing the structure of protein complexes. 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-linking reagent and/or protein, and label-free methods. We report Xlink-Identifier, a comprehensive data analysis platform that has been developed to support label-free analyses. It can identify inter-peptide, intra-peptide, and deadend cross-links as well as underivatized peptides. The software streamlines data pre-processing, peptide scoring, and visualization and provides an overall data analysis strategy for studying protein-protein interactions and protein structure using mass spectrometry. The software has been evaluated using a custom synthesized cross-linking reagent that features an enrichment tag. Xlink-Identifier offers the potential to perform large-scale identifications of protein-protein interactions using tandem mass spectrometry. PMID:21175198

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

2011-01-01

252

Drug-like annotation and duplicate analysis of a 23-supplier chemical database totalling 2.7 million compounds.  

PubMed

We have implemented five drug-like filters, based on 1D and 2D molecular descriptors, and applied them to characterize the drug-like properties of commercially available chemical compounds. In addition to previously published filters (Lipinski and Veber), we implemented a filter for medicinal chemistry tractability based on lists of chemical features drawn up by a panel of medicinal chemists. A filter based on the modeling of aqueous solubility (>1 microM) was derived in-house, as well as another based on the modeling of Caco-2 passive membrane permeability (>10 nm/s). A library of 2.7 million compounds was collated from the 23 compound suppliers and analyzed with these filters, highlighting a tendency toward highly lipophilic compounds. The library contains 1.6 M unique structures, of which 37% (607,223) passed all five drug-like filters. None of the 23 suppliers provides all the members of the drug-like subset, emphasizing the benefit of considering compounds from various compound suppliers as a source of diversity for drug discovery. PMID:15032546

Baurin, N; Baker, R; Richardson, C; Chen, I; Foloppe, N; Potter, A; Jordan, A; Roughley, S; Parratt, M; Greaney, P; Morley, D; Hubbard, R E

2004-01-01

253

Natural chemical markers identify source and date of introduction of an exotic species: lake trout  

E-print Network

(Salvelinus namaycush) in Yellowstone Lake Andrew R. Munro, Thomas E. McMahon, and James R. Ruzycki Abstract of introduction of exotic lake trout (Salvelinus namaycush) into Yellowstone Lake, Wyoming, USA. Otolith Sr identifier la source probable et la date d'introduction des touladis (Salvelinus namaycush) exoti- ques du

McMahon, Thomas E.

254

DEVELOPMENT OF A NOVEL, CELL-BASED CHEMICAL SCREEN TO IDENTIFY INHIBITORS OF INTRAPHAGOSOMAL LIPOLYSIS IN MACROPHAGES  

PubMed Central

Macrophages play a central role in tissue homeostasis and the immune system. Their primary function is to internalize cellular debris and microorganisms for degradation within their phagosomes. In this context, their capacity to process and sequester lipids such as triacylglycerides and cholesteryl esters makes them key players in circulatory diseases such as atheroclerosis. To discover new inhibitors of lipolytic processing within the phagosomal system of the macrophage we have developed a novel, cell-based assay suitable for high-throughput screening. We employed particles carrying a fluorogenic triglyceride substrate and a calibration fluor to screen for inhibitors of phagosomal lipolysis. A panel of secondary assays were employed to discriminate between lipase inhibitors and compounds that perturbed general phagosomal trafficking events. This process enabled us to identify a new structural class of pyrazole-methanone compounds that directly inhibit lysosomal and lipoprotein lipase activity. PMID:20653015

VanderVen, Brian C.; Hermetter, Albin; Huang, Amy; Maxfield, Fredrick R; Russell, David G; Yates, Robin M.

2010-01-01

255

Managing, Profiling and Analyzing a Library of 2.6 Million Compounds Gathered from 32 Chemical Providers  

E-print Network

by Java code. The druglikeness and leadlikeness are estimated with ,,in-house scores using functions-Throughput Screening. InChI: IUPAC International Chemical Identifier. JNI: Java Native Interface. MW: Molecular Weight knowledge of the features of the commercially available chemical libraries. Except ,,Big Pharmas, companies

Paris-Sud XI, Université de

256

Comparison of predicted and derived measures of volatile organic compounds inside four relocatable classrooms due to identified interior finish sources  

Microsoft Academic Search

Indoor exposures to toxic and odorous volatile organic compounds (VOCs) are of general concern. Recently, VOCs in portable or relocatable classrooms (RCs) have received particular attention. However, very little was known about indoor environmental quality (IEQ) and the sources, composition, and indoor concentrations of VOCs in RCs. This project task focused on developing and demonstrating a process for selecting interior

Alfred T. Hodgson; Derek G. Shendell; William J. Fisk; Michael G. Apte

2003-01-01

257

Identifying Modifiers of Tamoxifen Sensitivity Using High-Throughput Genetic and Chemical Screens  

Microsoft Academic Search

Endocrine therapies, which inhibit estrogen receptor (ER?) signalling, are the most common and effective treatments for ER?\\u000a positive breast cancer. However, the utility of these agents is limited by the frequent development of resistance. The precise\\u000a mechanisms underlying endocrine therapy resistance remain incompletely understood. In our laboratory, an RNA interference\\u000a (RNAi) screen was used to identify modifiers of sensitivity to

Elizabeth Iorns; Christopher J. Lord; Alan Ashworth

258

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

SciTech Connect

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.

Cone, M.V.; Baldauf, M.F.; Martin, F.M. (comps.) [comps.

1981-12-01

259

Development of a fission yeast-based high throughput screen to identify chemical regulators of cAMP phosphodiesterases  

PubMed Central

Cyclic nucleotide phosphodiesterases (PDEs) comprise a superfamily of enzymes that serve as drug targets in many human diseases. There is a continuing need to identify high-specificity inhibitors that affect individual PDE families or even subtypes within a single family. We describe a fission yeast-based high throughput screen to detect inhibitors of heterologously-expressed cAMP PDEs. The utility of this system is demonstrated by the construction and characterization of strains that express mammalian PDE2A, PDE4A, PDE4B, and PDE8A and respond appropriately to known PDE2A and PDE4 inhibitors. High throughput screens of two bioactive compound libraries for PDE inhibitors using strains expressing PDE2A, PDE4A, PDE4B, and the yeast PDE Cgs2 identified known PDE inhibitors and members of compound classes associated with PDE inhibition. We verified that the furanocoumarin imperatorin is a PDE4 inhibitor based on its ability to produce a PDE4-specific elevation of cAMP levels. This platform can be used to identify PDE activators, as well as genes encoding PDE regulators, which could serve as targets for future drug screens. PMID:18227226

Ivey, F. Douglas; Wang, Lili; Demirbas, Didem; Allain, Christina; Hoffman, Charles S.

2010-01-01

260

Chemical separation and structural identification of EOR-active compounds in water-soluble petroleum sulfonate  

SciTech Connect

This work summarizes the results of a closely integrated interdisciplinary research consisting of physicochemical and EOR-activity studies directed toward isolating the active components from a commercial petroleum sulfonate (Witco's Pyronate-40) and identifying their chemical structure. Samples of Pyronate-40 in the acid, sodium salt, and methyl ester forms were fractionated chromatographically. The EOR-activities of the chromatographic fractions were determined by means of core flood tests using Berea Sandstone core. Ten-milligram samples of the most EOR-active fractions gave an oil recovery of 0.8 to 1.6 mL, which correspond to 4.4 to 2.2 lb, respectively, of the sulfonate for producing one barrel of tertiary oil. The EOR-active fractions were subjected to further resolutions by means of Flash chromatography, followed by reversed phase high performance liquid chromatography. Gas chromatography/mass spectral examination of the EOR-active fraction has indicated the presence of a number of components among which the identifiable ones corresponded structurally to the synthetic alkylaryl sulfonates, such as 5-(4-ethylbenzene-3-sulfonic acid)-dodecane.

Rajan, K.S.; Chettur, G.; Kamath, K.I.

1983-01-01

261

Control of the chemical state change of sulfur in solid compound targets during high-resolution PIXE measurements  

NASA Astrophysics Data System (ADS)

A high-energy-resolution wavelength-dispersive (WD) X-ray spectrometer in the Johansson geometry, which allowed energy resolution below the natural linewidth of the K ? lines was employed in measurements of the proton-induced K ? X-ray emission spectra for six typical sulfur compounds (CdS, Na2SO3, Na2 S2O5, NaHSO3, (NH4)2SO4, and Na2SO4) to investigate the chemical state change during 2.4-MeV proton irradiation with a current density of 7.5 nA/mm2. We found that the chemical state change of each compound depended on the various factors affecting the surface temperature increase, such as target thickness, mounting method, and existence of active cooling during the measurement. The chemical state of sulfur on the target surface of S4+ compounds was gradually changed into S6+ without exception through irradiation under poor cooling conditions. Sulfur compounds of the S0 and S6+ states with closed shell structures were proven to be chemically stable against proton bombardment, as expected. However, (NH4)2SO4 was found to be most sensitive to proton irradiation among the sulfur compounds, and S0, one of the reaction products, became a major element at doses higher than 3 × 108 Gy. If thick targets were mounted by using a carbon adhesive tape, chemical state change could be observed in some cases even with lowtemperature cooling down to -80 °C, however, the chemical state change seemed to be remarkably suppressed by using very thin targets mounted with a silver paste even without active cooling. In conclusion, the chemical states of sulfur compounds could be preserved without significant change for an accumulated dose of about 3 × 107 Gy, equivalent to a typical high-resolution PIXE scanning period, by adopting a proper target preparation scheme to discharge proton-induced thermal energy effectively from the irradiated target surface.

Woo, Hyung-Joo; Choi, Han-Woo; Kim, Gi-Dong; Kim, Joon-Kon

2012-07-01

262

Quantitative Chemical Proteomics Approach to Identify Posttranslational Modification-mediated Protein-protein Interactions  

PubMed Central

Post-translational modifications (PTMs) (e.g. acetylation, methylation, and phosphorylation) play crucial roles in regulating the diverse protein-protein interactions involved in essentially every cellular process. While significant progress has been made to detect PTMs, profiling protein-protein interactions mediated by these PTMs remains a challenge. Here, we report a method that combines a photo-cross-linking strategy with stable isotope labeling in cell culture (SILAC)-based quantitative mass spectrometry to identify PTM-dependent protein-protein interactions. To develop and apply this approach, we focused on trimethylated lysine-4 at the histone H3 ‘tail’ (H3K4Me3), a PTM linked to actively transcribed regions on chromosomes. Our approach identified proteins previously known to recognize this modification and MORC3 as a new H3K4Me3 ‘reader’. This study indicates that our cross-linking-assisted and SILAC-based protein identification (CLASPI) approach can be used to profile protein-protein interactions mediated by PTMs, such as lysine methylation. PMID:22239320

Li, Xiang; Foley, Emily A.; Molloy, Kelly R.; Li, Yinyin; Chait, Brian T.; Kapoor, Tarun M.

2012-01-01

263

Chemical characterization of oak heartwood from Spanish forests of Quercus pyrenaica (Wild.). Ellagitannins, low molecular weight phenolic, and volatile compounds.  

PubMed

The need for new sources of quality wood supply for cooperage has led to looking into the possibility of utilizing Quercus pyrenaica Wild. oak, a species native to the Iberian peninsula, as an alternative to other European (Quercus robur and Qurecus petraea) and American (Quercus alba) oaks. The low molecular weight phenolic composition, ellagitannins, and volatile compounds (including a wide range of compound families such as volatile phenols, furanic compounds, lactones, phenyl ketones, other lignin-derived compounds, and volatile compounds related to off-flavors) of green heartwood from Spanish forest regions were studied by HPLC and GC, in order to know its enological characteristics. The chemical composition of Q. pyrenaica is similar to that of other species commonly used in cooperage to make barrels, showing only quantitative differences that were more significant with respect to American than to French species. The four provenance regions studied showed similar chemical composition, with high variability among individuals, often higher than the variability among regions of provenance, but in line with that described in other European and American oak woods. Therefore, this species must be considered to be suitable for aging wine. PMID:17032045

Fernandez de Simón, Brígida; Sanz, Miriam; Cadahía, Estrella; Poveda, Pilar; Broto, Miguel

2006-10-18

264

Discriminative power of chemically sensitive silicon nanowire field effect transistors to volatile organic compounds.  

PubMed

We report on the sensing of different polar and nonpolar volatile organic compounds (VOCs) in an atmosphere with background humidity (relative humidity: 40%), using molecularly modified silicon nanowire field effect transistors (SiNW FETs). In this endeavor, a systematic comparative analysis is performed with: (i) SiNW FETs that were functionalized with a series of molecules having different electron-withdrawing and electron-donating end groups; and (ii) SiNW FETs that are functionalized with a series of molecules having similar functional groups but different backbone lengths. The analysis of the sensing signals are focused on three main FET parameters: (i) changes in the threshold voltage, (ii) changes in the carrier mobility, and (iii) changes in the on-current, compared to the baseline values under vacuum. Using discriminant factor analysis, the performance of the molecularly modified SiNW FETs is further analyzed as sensors array. The combination of sensors having the best discriminative power between the various VOCs are identified and discussed in terms of their constituent surface modifications. PMID:24144671

Ermanok, Rotem; Assad, Ossama; Zigelboim, Keren; Wang, Bin; Haick, Hossam

2013-11-13

265

Associations between self-reported odour annoyance and volatile organic compounds in 'Chemical Valley', Sarnia, Ontario.  

PubMed

Annoyance produced by air pollution has been suggested as a useful proxy for determining ambient air pollution exposure. However, most of the studies, to date, have focused on nitrogen dioxide and sulphur dioxide, with no work done on volatile organic compounds (VOC). This study is aimed at examining the associations between odour annoyance and VOC in 'Chemical Valley', Sarnia, Ontario, Canada. Annoyance scores were extracted from a community health survey (N = 774), and exposures to VOC were estimated from respondents' six-digit alphanumeric postal codes using land use regression models. Univariate analyses were used to explore the relationships between odour annoyance and modelled pollutants, whilst multivariate ordinal logistic regression was utilized to examine the determinants of odour annoyance. The results indicate that odour annoyance is significantly associated with modelled benzene, toluene, ethylbenzene, o-xylene and (m + p) xylene (BTEX) pollutants. The findings also show that the determinants of odour annoyance in the context of VOC include gender, number of relatives in the community, perception of air pollution, community satisfaction, medical checkups, ability to cope with daily life demands and general symptoms. When compared, the analysis indicates that Sarnia residents respond to considerably lower BTEX concentrations than the allowable 'safe' levels in the province of Ontario. In general, the results exhibit a dose-response gradient with annoyance score increasing with rising modelled pollutant concentrations. The observed relationships suggest that odour annoyance might be a function of true exposure and may serve as a proxy for air quality and ambient air pollution monitoring. However, questionnaire-based odour annoyance scores need to be longitudinally validated across different geographical scales and pollutants if they are to be adopted at the national level. PMID:23014924

Atari, Dominic Odwa; Luginaah, Isaac N; Gorey, Kevin; Xu, Xiaohong; Fung, Karen

2013-06-01

266

Chemical decomposition of iron in Spanish coal pyrolysis identified by Moessbauer spectroscopy at different temperatures  

SciTech Connect

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.

Ahmed, M.A.; Blesa, M.J.; Moliner, R. [Taif University, El Taif (Saudi Arabia). Faculty of Science

2007-07-01

267

Chemical Synthesis Database  

NSDL National Science Digital Library

This database provides information on thousands of chemical compounds, including synthesis references and physical properties. The database is searchable by keyword and browseable by journal title. For each compound, the information includes molecular formula and weight, Chemical Abstracts Service (CAS) numbers, International Chemical Identifier (InChIKey), and Simplified Molecular Input Line Entry System (SMILES) notation. There is also information on synonyms, physical properties (boiling and melting points, density), an illustration of chemical structure, spectral data, and links to additional data.

268

Determination of chemical warfare agents in soil and material samples: Gas chromatographic analysis of phenylarsenic compounds (sternutators) (1st communication).  

PubMed

A gas Chromatographic method for the determination of phenylarsenic compounds (sternutators) and their metabolites in soil and material samples is described. The chemical warfare agents (CWA), but not their hydrolysis and oxidation products, can be detected with GC/ECD. After derivatization with thiols or dithiols, the sum of diphenylarsenic and phenylarsenic compounds can be determined with GC/ECD. The comparison of the analytical results with and without derivatization shows that the sternutators in the investigated samples are metabolized in part. PMID:19002393

Haas, R; Krippendorf, A

1997-01-01

269

A High-Resolution Genetic Map of Yellow Monkeyflower Identifies Chemical Defense QTLs and Recombination Rate Variation  

PubMed Central

Genotyping-by-sequencing methods have vastly improved the resolution and accuracy of genetic linkage maps by increasing both the number of marker loci as well as the number of individuals genotyped at these loci. Using restriction-associated DNA sequencing, we construct a dense linkage map for a panel of recombinant inbred lines derived from a cross between divergent ecotypes of Mimulus guttatus. We used this map to estimate recombination rate across the genome and to identify quantitative trait loci for the production of several secondary compounds (PPGs) of the phenylpropanoid pathway implicated in defense against herbivores. Levels of different PPGs are correlated across recombinant inbred lines suggesting joint regulation of the phenylpropanoid pathway. However, the three quantitative trait loci identified in this study each act on a distinct PPG. Finally, we map three putative genomic inversions differentiating the two parental populations, including a previously characterized inversion that contributes to life-history differences between the annual/perennial ecotypes. PMID:24626287

Holeski, Liza M.; Monnahan, Patrick; Koseva, Boryana; McCool, Nick; Lindroth, Richard L.; Kelly, John K.

2014-01-01

270

Economics of resynchronization strategies including chemical tests to identify nonpregnant cows.  

PubMed

Our objectives were to assess (1) the economic value of decreasing the interval between timed artificial insemination (TAI) services when using a pregnancy test that allows earlier identification of nonpregnant cows; and (2) the effect of pregnancy loss and inaccuracy of a chemical test (CT) on the economic value of a pregnancy test for dairy farms. Simulation experiments were performed using a spreadsheet-based decision support tool. In experiment 1, we assessed the effect of changing the interbreeding interval (IBI) for cows receiving TAI on the value of reproductive programs by simulating a 1,000-cow dairy herd using a combination of detection of estrus (30 to 80% of cows detected in estrus) and TAI. The IBI was incremented by 7d from 28 to 56 d to reflect intervals either observed (35 to 56 d) or potentially observed (28 d) in dairy operations. In experiment 2, we evaluated the effect of accuracy of the CT and additional pregnancy loss due to earlier testing on the value of reproductive programs. The first scenario compared the use of a CT 31 ± 3 d after a previous AI with rectal palpation (RP) 39 ± 3 d after AI. The second scenario used a CT 24 ± 3 d after AI or transrectal ultrasound (TU) 32 d after AI. Parameters evaluated included sensitivity (Se), specificity (Sp), questionable diagnosis (Qd), cost of the CT, and expected pregnancy loss. Sensitivity analysis was performed for all possible combinations of parameter values to determine their relative importance on the value of the CT. In experiment 1, programs with a shorter IBI had greater economic net returns at all levels of detection of estrus, and use of chemical tests available on the market today might be beneficial compared with RP. In experiment 2, the economic value of programs using a CT could be either greater or less than that of RP and TU, depending on the value for each of the parameters related to the CT evaluated. The value of the program using the CT was affected (in order) by (1) Se, (2) Sp, (3) pregnancy loss, (4) proportion of Qd, (5) percentage of cows AI in estrus, and (6) cost of CT. A change of 1% in the Se of the CT was 1.8 times more important than a similar change in Sp or pregnancy loss, and 13.7, 55.0, and 305.8 times more important than similar changes in Qd, cows inseminated in estrus, and cost of CT. We conclude that the major effect of using a CT is the potential of decreasing the IBI. Moreover, inaccuracy of the CT and additional pregnancy loss due to earlier testing resulted in smaller economic differences than when using RP or TU 8d later. PMID:23261387

Giordano, J O; Fricke, P M; Cabrera, V E

2013-02-01

271

GC/MS-positive ion chemical ionization and MS/MS study of volatile benzene compounds in five different woods used in barrel making.  

PubMed

Extracts from acacia, chestnut, cherry, mulberry, and oak wood, used in making barrels for aging wine and spirits were studied by GC/MS positive ion chemical ionization (PICI). Wood chips were extracted by a 50% water/ethanol solution and a tartrate buffer pH 3.2-12% ethanol (model wine) solution. The principal compounds identified in extracts were guaiacol-containing aldehydes and alcohols, such as benzaldehyde and derivatives, vanillin and syringaldehyde, cinnamaldehyde and coniferaldehyde, eugenol and methoxyeugenol, guaiacol and methoxyguaiacol derivatives. PICI using methane as reagent gas produced a high yield of the protonated molecular ion of volatile phenols, compound identification was confirmed by collision-induced-dissociation (CID) experiments on [M + H](+) species. MS/MS fragmentation patterns were studied with standard compounds: guaiacol-containing molecules were characterized by neutral methyl and methanol losses, benzaldehyde derivatives by CO loss. Acacia wood extracts contained significant syringaldehyde and anisaldehyde, but no eugenol and methoxyeugenol. Significant syringaldehyde, eugenol and methoxyeugenol, and high vanillin were found in chestnut and oak wood extracts; low presence of volatile benzene compounds was found in mulberry wood extracts. Cherry wood extracts were characterized by the presence of several benzaldehyde derivatives and high trimethoxyphenol. PMID:17370248

Flamini, Riccardo; Dalla Vedova, Antonio; Cancian, Davide; Panighel, Annarita; De Rosso, Mirko

2007-05-01

272

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

PubMed Central

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

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

2013-01-01

273

Chemical fate and biological effects of several endocrine disrupters compounds in two echinoderm species  

Microsoft Academic Search

Two echinoderm species, the sea urchin Paracentrotus lividus and the feather star Antedon mediterranea, were exposed for 28 days to several EDCs: three putative androgenic compounds, triphenyltin (TPT), fenarimol (FEN), methyltestosterone\\u000a (MET), and two putative antiandrogenic compounds, p,p?-DDE (DDE) and cyproterone acetate (CPA). The exposure nominal concentrations were from 10 to 3000 ng L?1, depending on the compound. This paper is an attempt

Michela Sugni; Paolo Tremolada; Cinta Porte; Alice Barbaglio; Francesco Bonasoro; M. Daniela Candia Carnevali

2010-01-01

274

Influence of chemical modification of polymeric resin on retention of polar compounds in solid-phase extraction  

Microsoft Academic Search

Summary  Three polymeric adsorbents, two of which had been chemically modified with different hydrophilic functional moieties and the\\u000a third, which was the corresponding unmodified polystyrene-divinylbenzene (PSDVB) resin, were compared for solid-phase extraction\\u000a (SPE) of several polar pesticides and phenolic compounds from water samples. The SPE system was online coupled to a liquid\\u000a chromatograph with UV detector.\\u000a \\u000a Chemical modification of the PS-DVB

N. Masqué; M. Galiá; R. M. Marcé; F. Borrull

1999-01-01

275

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

Microsoft Academic Search

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

Manfred Köhler; Klaus Hofmann; Fernando Völsgen; Kerstin Thurow; Andreas Koch

2001-01-01

276

A comparison of {sup 252}Cf and 14-MeV neutron excitation to identify chemical warfare agents by PGNAA  

SciTech Connect

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.

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

277

Effective discrimination of antimalarial potency of artemisinin compounds based on quantum chemical calculations of their reaction mechanism  

Microsoft Academic Search

The reaction mechanism of 12 antimalarial artemisinin compounds with two competitive pathways was studied by means of quantum chemical calculations using the IMOMO(B3LYP\\/6-31(d,p):HF\\/3-21G) method. The oxygen-centered radicals, carbon-centered radicals, and transition states (TS) in both pathways were geometrically optimized. The obtained kinetic and thermodynamic energy profiles show that homolytic C–C cleavage reaction (pathway 2) is energetically more preferable than an

Somsak Tonmunphean; Vudhichai Parasuk; Sirirat Kokpol

2006-01-01

278

The chemical composition of plant galls: are levels of nutrients and secondary compounds controlled by the gall-former?  

Microsoft Academic Search

The chemical composition of galled and ungalled plant tissue was compared in a series of experiments. Gall and adjacent plant\\u000a tissue was analysed for 20 species of gall-former on 11 different plant species. There were clear differences between galled\\u000a and ungalled tissue in levels of nutrients and secondary compounds. Gall tissue generally contained lower levels of nitrogen\\u000a and higher levels

S. E. Hartley

1998-01-01

279

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

PubMed

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

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

2013-10-25

280

Cytochrome P450 119 Compounds I formed by chemical oxidation and photooxidation are the same species  

PubMed Central

Compound I from cytochrome P450 119 prepared by the photooxidation method involving peroxynitrite oxidation of the resting enzyme to Compound II followed by photooxidation to Compound I was compared to Compound I generated by m-chloroperoxybenzoic acid (MCPBA) oxidation of the resting enzyme. The two methods gave the same UV-visible spectra, the same products from oxidations of lauric acid and palmitic acid and their (?-2,?-2,?-3,?-3)-tetradeuterated analogues, and the same kinetics for oxidations of lauric acid and caprylic acid. The experimental identities between the transients produced by the two methods leave no doubt that the same Compound I speices is formed by the two methods. PMID:23108625

Su, Zhi; Horner, John H.

2014-01-01

281

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

SciTech Connect

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.

Steven B. Hawthorne

2007-04-15

282

Merging bioactivity with liquid chromatography-mass spectrometry-based chemometrics to identify minor immunomodulatory compounds from a Micronesian adaptogen, Phaleria nisidai.  

PubMed

This study presents a strategy based on repeatable reversed-phase LC-TOF-MS methods and chemometric statistical tools, including untargeted PCA and supervised OPLS-DA models, to identify low-yielding compounds with potent immunostimulant activity in Phaleria nisidai (Thymelaeaceae), a plant with a history of use as an adaptogen on the islands of Palau in Micronesia. IFN? ELISA assays were used to classify chromatographic fractions according to imunomodulatory activity prior to LC-TOF-MS chemometric analysis to target and identify compounds likely to contribute to observed activity. Simplexin, a daphnane diterpene ester, was identified for the first time from this genus and caused an increase in the production of cytokines (IFN?, IL1?, IL6, and IL13) by peripheral blood mononuclear cells. Five other daphnane diterpene esters were tentatively identified for the first time from this plant based on mass spectral data and are marker metabolites distinguishing active from inactive fractions. This analytical approach increased the efficiency of bioactivity-guided fractionation and has the potential to minimize redundant isolation and identify minor constituents with potent activity from a complex matrix. PMID:25218635

Kulakowski, Daniel M; Wu, Shi-Biao; Balick, Michael J; Kennelly, Edward J

2014-10-17

283

Deduction of the chemical state and the electronic structure of Nd2Fe14B compound from X-ray photoelectron spectroscopy core-level and valence-band spectra  

NASA Astrophysics Data System (ADS)

Characterization of chemical state and electronic structure of the technologically important Nd2Fe14B 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 Nd2Fe14B compound as a function of Ar ion sputtering time. The chemical state of Fe and that of B in Nd2Fe14B compound can be clearly determined to be 0 and -3, respectively. The Nd in Nd2Fe14B compound is found to have the chemical state of close to +3 instead of +3 as compared with the Nd in Nd2O3. In addition, by comparing the valence-band spectrum of Nd2Fe14B compound to that of the pure Fe, the contributions from Nd, Fe, and B to the valence-band structure of Nd2Fe14B 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 Nd2Fe14B compound.

Wang, Jing; Liang, Le; Zhang, Lanting; Sun, Limin; Hirano, Shinichi

2014-10-01

284

Thymine vanadyl(II) compound as a diabetic drug model: Chemical spectroscopic and antimicrobial assessments  

NASA Astrophysics Data System (ADS)

The aim of this study was to synthesize a novel bifunctionalized thymine vanadyl(II) compound. The solid vanadyl(II) compound has been characterized by elemental analyses (CHN), Raman laser, infrared spectra, molar conductivity, electronic spectra, thermogravimetric analyses (TGA), scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) studies. Electronic and magnetic measurements have confirmed that the speculated geometry of vanadyl(II) compound is square pyramidal geometry. The microbial test was performed for the vanadyl complex against some kinds of bacteria and fungi. The results suggested that [VO(Thy)2] adduct has an anti-diabetic profile.

El-Sayed, Mohamed Y.; Refat, Moamen S.

2014-09-01

285

Investigation of the Chemical Identity of Soluble Organophosphorus Compounds Found in Natural Waters.  

National Technical Information Service (NTIS)

Four algal species (Chlamydomonas reinhardtii, Chlorella pyrenoidosa, Anacystis nidulans, and Anabaena flos-aquae) were grown in batch culture on 32p labelled media to yield dissolved organic phosphorus (DOP) compounds containing a radioactive tag. The DO...

R. A. Minear

1978-01-01

286

Antirheumatoid Arthritis Activities and Chemical Compositions of Phenolic Compounds-Rich Fraction from Urtica atrichocaulis, an Endemic Plant to China  

PubMed Central

Urtica atrichocaulis, an endemic plant to China, is commonly used to treat rheumatoid arthritis even though its pharmaceutical activities and chemical constituents were not studied. Herein, we reported our investigations on the chemical compositions of the phenolic compounds-rich fraction from U. atrichocaulis (TFUA) and their antirheumatoid arthritis activities. We found that the TFUA significantly inhibited the adjuvant-induced rats arthritis, carrageenin-induced rats paw edema, cotton pellet-induced mice granuloma, and the acetic acid-induced mice writhing response. Our phytochemical investigations on the TFUA resulted in the first-time isolation and identification of 17 phenolic constituents and a bis (5-formylfurfuryl) ether. The extensive HPLC analysis also revealed the chemical compositions of TFUA. Our further biological evaluation of the main phenolic components, individually and collectively, indicated that the antirheumatoid arthritis activities of TFUA were the combined effect of multiple phenolic constituents. PMID:21904564

Wang, Mengyue; Li, Ke; Nie, Yuxiao; Wei, Yingfang; Li, Xiaobo

2012-01-01

287

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

PubMed Central

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

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

2013-01-01

288

Quantitative Chemical Proteomics Identifies Novel Targets of the Anti-cancer Multi-kinase Inhibitor E-3810*  

PubMed Central

Novel drugs are designed against specific molecular targets, but almost unavoidably they bind non-targets, which can cause additional biological effects that may result in increased activity or, more frequently, undesired toxicity. Chemical proteomics is an ideal approach for the systematic identification of drug targets and off-targets, allowing unbiased screening of candidate interactors in their natural context (tissue or cell extracts). E-3810 is a novel multi-kinase inhibitor currently in clinical trials for its anti-angiogenic and anti-tumor activity. In biochemical assays, E-3810 targets primarily vascular endothelial growth factor and fibroblast growth factor receptors. Interestingly, E-3810 appears to inhibit the growth of tumor cells with low to undetectable levels of these proteins in vitro, suggesting that additional relevant targets exist. We applied chemical proteomics to screen for E-3810 targets by immobilizing the drug on a resin and exploiting stable isotope labeling by amino acids in cell culture to design experiments that allowed the detection of novel interactors and the quantification of their dissociation constant (Kd imm) for the immobilized drug. In addition to the known target FGFR2 and PDGFR?, which has been described as a secondary E-3810 target based on in vitro assays, we identified six novel candidate kinase targets (DDR2, YES, LYN, CARDIAK, EPHA2, and CSBP). These kinases were validated in a biochemical assay and—in the case of the cell-surface receptor DDR2, for which activating mutations have been recently discovered in lung cancer—cellular assays. Taken together, the success of our strategy—which integrates large-scale target identification and quality-controlled target affinity measurements using quantitative mass spectrometry—in identifying novel E-3810 targets further supports the use of chemical proteomics to dissect the mechanism of action of novel drugs. PMID:24696502

Colzani, Mara; Noberini, Roberta; Romanenghi, Mauro; Colella, Gennaro; Pasi, Maurizio; Fancelli, Daniele; Varasi, Mario; Minucci, Saverio; Bonaldi, Tiziana

2014-01-01

289

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

USGS Publications Warehouse

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.

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

290

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

PubMed

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

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

2012-03-01

291

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

ERIC Educational Resources Information Center

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…

Talanquer, Vicente

2008-01-01

292

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)

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.

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

2014-10-01

293

Screening Compounds with a Novel High-Throughput ABCB1-Mediated Efflux Assay Identifies Drugs with Known Therapeutic Targets at Risk for Multidrug Resistance Interference  

PubMed Central

ABCB1, also known as P-glycoprotein (P-gp) or multidrug resistance protein 1 (MDR1), is a membrane-associated multidrug transporter of the ATP-binding cassette (ABC) transporter family. It is one of the most widely studied transporters that enable cancer cells to develop drug resistance. Reliable high-throughput assays that can identify compounds that interact with ABCB1 are crucial for developing new therapeutic drugs. A high-throughput assay for measuring ABCB1-mediated calcein AM efflux was developed using a fluorescent and phase-contrast live cell imaging system. This assay demonstrated the time- and dose-dependent accumulation of fluorescent calcein in ABCB1-overexpressing KB-V1 cells. Validation of the assay was performed with known ABCB1 inhibitors, XR9576, verapamil, and cyclosporin A, all of which displayed dose-dependent inhibition of ABCB1-mediated calcein AM efflux in this assay. Phase-contrast and fluorescent images taken by the imaging system provided additional opportunities for evaluating compounds that are cytotoxic or produce false positive signals. Compounds with known therapeutic targets and a kinase inhibitor library were screened. The assay identified multiple agents as inhibitors of ABCB1-mediated efflux and is highly reproducible. Among compounds identified as ABCB1 inhibitors, BEZ235, BI 2536, IKK 16, and ispinesib were further evaluated. The four compounds inhibited calcein AM efflux in a dose-dependent manner and were also active in the flow cytometry-based calcein AM efflux assay. BEZ235, BI 2536, and IKK 16 also successfully inhibited the labeling of ABCB1 with radiolabeled photoaffinity substrate [125I]iodoarylazidoprazosin. Inhibition of ABCB1 with XR9576 and cyclosporin A enhanced the cytotoxicity of BI 2536 to ABCB1-overexpressing cancer cells, HCT-15-Pgp, and decreased the IC50 value of BI 2536 by several orders of magnitude. This efficient, reliable, and simple high-throughput assay has identified ABCB1 substrates/inhibitors that may influence drug potency or drug-drug interactions and predict multidrug resistance in clinical treatment. PMID:23593196

Ansbro, Megan R.; Shukla, Suneet; Ambudkar, Suresh V.; Yuspa, Stuart H.; Li, Luowei

2013-01-01

294

Isolation and Chemical Structural Characterisation of a Compound with Antioxidant Activity from the Roots of Senna italica  

PubMed Central

Senna italica, a member of the Fabaceae family (subfamily Caesalpiniaceae), is widely used in South African traditional medicine to treat a number of disease conditions. Aqueous extracts of the plant are mainly used to treat sexually transmitted infections and intestinal complications. The roots of S. italica were ground to a fine powder and sequentially extracted with n-hexane, dichloromethane, acetone, and methanol using serial exhaustive extraction (SEE) method. Thin layer chromatography was used to analyse the phytochemical composition of the extracts and DPPH radical scavenging method to detect the presence of antioxidant compounds. The bioassay guided fractionation of the acetone fraction afforded an antioxidant compound with free radical scavenging activity. The isolated compound was subsequently identified as 3,4?,5-trihydroxystilbene (resveratrol). This study represents the first report of the stilbene resveratrol in S. italica. PMID:23843877

Mokgotho, Matlou Phineas; Gololo, Stanley Sechene; Masoko, Peter; Shai, Leshwene Jeremiah; Bagla, Victor Patrick; Eloff, Jacobus Nicolaas

2013-01-01

295

Development of a Chemical Genetic Approach for Human Aurora B Kinase Identifies Novel Substrates of the Chromosomal Passenger Complex*  

PubMed Central

To understand how the chromosomal passenger complex ensures chromosomal stability, it is crucial to identify its substrates and to find ways to specifically inhibit the enzymatic core of the complex, Aurora B. We therefore developed a chemical genetic approach to selectively inhibit human Aurora B. By mutating the gatekeeper residue Leu-154 in the kinase active site, the ATP-binding pocket was enlarged, but kinase function was severely disrupted. A unique second site suppressor mutation was identified that rescued kinase activity in the Leu-154 mutant and allowed the accommodation of bulky N6-substituted adenine analogs. Using this analog-sensitive Aurora B kinase, we found that retention of the chromosomal passenger complex at the centromere depends on Aurora B kinase activity. Furthermore, analog-sensitive Aurora B was able to use bulky ATP?S analogs and could thiophosphorylate multiple proteins in cell extracts. Utilizing an unbiased approach for kinase substrate mapping, we identified several novel substrates of Aurora B, including the nucleosomal-binding protein HMGN2. We confirmed that HMGN2 is a bona fide Aurora B substrate in vivo and show that its dynamic association to chromatin is controlled by Aurora B. PMID:22267324

Hengeveld, Rutger C. C.; Hertz, Nicholas T.; Vromans, Martijn J. M.; Zhang, Chao; Burlingame, Alma L.; Shokat, Kevan M.; Lens, Susanne M. A.

2012-01-01

296

Inhibitors of ROS production by the ubiquinone-binding site of mitochondrial complex I identified by chemical screening.  

PubMed

Mitochondrial production of reactive oxygen species is often considered an unavoidable consequence of aerobic metabolism and currently cannot be manipulated without perturbing oxidative phosphorylation. Antioxidants are widely used to suppress effects of reactive oxygen species after formation, but they can never fully prevent immediate effects at the sites of production. To identify site-selective inhibitors of mitochondrial superoxide/H2O2 production that do not interfere with mitochondrial energy metabolism, we developed a robust small-molecule screen and secondary profiling strategy. We describe the discovery and characterization of a compound (N-cyclohexyl-4-(4-nitrophenoxy)benzenesulfonamide; CN-POBS) that selectively inhibits superoxide/H2O2 production from the ubiquinone-binding site of complex I (site I(Q)) with no effects on superoxide/H2O2 production from other sites or on oxidative phosphorylation. Structure/activity studies identified a core structure that is important for potency and selectivity for site I(Q). By employing CN-POBS in mitochondria respiring on NADH-generating substrates, we show that site I(Q) does not produce significant amounts of superoxide/H2O2 during forward electron transport on glutamate plus malate. Our screening platform promises to facilitate further discovery of direct modulators of mitochondrially derived oxidative damage and advance our ability to understand and manipulate mitochondrial reactive oxygen species production under both normal and pathological conditions. PMID:23994103

Orr, Adam L; Ashok, Deepthi; Sarantos, Melissa R; Shi, Tong; Hughes, Robert E; Brand, Martin D

2013-12-01

297

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

PubMed

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

Hishigaki, Haretsugu; Kuhara, Satoru

2011-01-01

298

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...

299

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

E-print Network

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 ...

Broekhuizen, Keith Edward, 1974-

2002-01-01

300

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 ...

301

Anti-Prion Activity of a Panel of Aromatic Chemical Compounds: In Vitro and In Silico Approaches  

PubMed Central

The prion protein (PrP) is implicated in the Transmissible Spongiform Encephalopathies (TSEs), which comprise a group of fatal neurodegenerative diseases affecting humans and other mammals. Conversion of cellular PrP (PrPC) into the scrapie form (PrPSc) is the hallmark of TSEs. Once formed, PrPSc aggregates and catalyzes PrPC misfolding into new PrPSc molecules. Although many compounds have been shown to inhibit the conversion process, so far there is no effective therapy for TSEs. Besides, most of the previously evaluated compounds failed in vivo due to poor pharmacokinetic profiles. In this work we propose a combined in vitro/in silico approach to screen for active anti-prion compounds presenting acceptable drugability and pharmacokinetic parameters. A diverse panel of aromatic compounds was screened in neuroblastoma cells persistently infected with PrPSc (ScN2a) for their ability to inhibit PK-resistant PrP (PrPRes) accumulation. From ?200 compounds, 47 were effective in decreasing the accumulation of PrPRes in ScN2a cells. Pharmacokinetic and physicochemical properties were predicted in silico, allowing us to obtain estimates of relative blood brain barrier permeation and mutagenicity. MTT reduction assays showed that most of the active compounds were non cytotoxic. Compounds that cleared PrPRes from ScN2a cells, were non-toxic in the MTT assay, and presented a good pharmacokinetic profile were investigated for their ability to inhibit aggregation of an amyloidogenic PrP peptide fragment (PrP109–149). Molecular docking results provided structural models and binding affinities for the interaction between PrP and the most promising compounds. In summary, using this combined in vitro/in silico approach we have identified new small organic anti-scrapie compounds that decrease the accumulation of PrPRes in ScN2a cells, inhibit the aggregation of a PrP peptide, and possess pharmacokinetic characteristics that support their drugability. These compounds are attractive candidates for prion disease therapy. PMID:24400098

Ferreira, Natalia C.; Marques, Icaro A.; Conceição, Wesley A.; Macedo, Bruno; Machado, Clarice S.; Mascarello, Alessandra; Chiaradia-Delatorre, Louise Domeneghini; Yunes, Rosendo Augusto; Nunes, Ricardo José; Hughson, Andrew G.; Raymond, Lynne D.; Pascutti, Pedro G.; Caughey, Byron; Cordeiro, Yraima

2014-01-01

302

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

NASA Astrophysics Data System (ADS)

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.

Douglas, T. A.

2013-12-01

303

INHERITANCE IN GUINEA PIGS OF THE SUSCEPTIBILITY TO SKIN SENSITIZATION WITH SIMPLE CHEMICAL COMPOUNDS  

PubMed Central

It has proved possible to set up lines of guinea pigs of significantly different susceptibilities towards a compound of simple structure, namely 2:4 dinitrochlorobenzene. This provides direct evidence that the type of sensitization under discussion is influenced by heredity. PMID:19871107

Chase, Merrill W.

1941-01-01

304

EVALUATION OF THE SEMIVOST METHOD FOR HALOGENATED COMPOUNDS AT A CHEMICAL MANUFACTURING FACILITY  

EPA Science Inventory

A field test was conducted to determine the applicability of the SemiVOST method (SW-846 Method 0010 (Sampling), SW-846 Draft Method 3542 (Sample Preparation), and SW-846 Method 8270 (Analysis)) to semivolatile halogenated organic compounds listed in Title Ill of the 1990 Clean A...

305

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...

306

Quantitative detection of chemical compounds in human hair with coherent anti-Stokes Raman scattering  

E-print Network

factors such as penetration depth, distribution pattern in the fiber, and local concentration and physical mechanisms that govern the interaction of hair-care products with the hair fiber. Electron is used to determine the distribution and concentration of selected compounds in intact human hair

Potma, Eric Olaf

307

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...

308

Chemical characterization of volatile organic compounds near the World Trade Center: Ambient concentrations and source apportionment  

Microsoft Academic Search

Concentrations of 53 volatile organic compounds (VOCs) are reported from four locations near the World Trade Center (WTC) (New York, USA) complex for canister samples collected from September 2001 through January 2002. Across the four sampling sites, mean concentrations ranged from 94.5 to 219?gm-3 for total VOCs. The highest mean concentrations for individual VOCs at any site were for ethane

David A. Olson; Gary A. Norris; Robert L. Seila; Matthew S. Landis; Alan F. Vette

2007-01-01

309

Extension of the K-Region Hypothesis of Carcinogenic Chemical Compounds  

Microsoft Academic Search

WORKING on suggestions put forward by Schmidt and by Swartholm, a number of French and English workers, notably A. Pullman, B. Pullman, P. Daudel, R. Daudel and C. A. Coulson, have developed a hypothesis relating the carcinogenic power of polycyclic aromatics to the structures of these compounds on the basis of quantum mechanics. Evidence has been accumulating in recent years

E. C. Kooyman; J. W. Heringa

1952-01-01

310

Stimulation of Ideas through Compound-Based Bibliometrics: Counting and Mapping Chemical Compounds for Analyzing Research Topics in Chemistry, Physics, and Materials Science  

PubMed Central

Counting compounds (rather than papers or citations) offers a new perspective for quantitative analyses of research activities. First of all, we can precisely define (compound-related) research topics and access the corresponding publications (scientific papers as well as patents) as a measure of research activity. We can also establish the time evolution of the publications dealing with specific compounds or compound classes. Moreover, the mapping of compounds by establishing compound-based landscapes has some potential to visualize the compound basis of research topics for further research activities. We have analyzed the rare earth compounds to give an example of a broad compound class. We present the number of the currently existing compounds and of the corresponding publications as well as the time evolution of the papers and patents. Furthermore, we have analyzed the rare earth cuprates (copper oxides) as an example of a narrower compound class to demonstrate the potential of mapping compounds by compound-based landscapes. We have quantified the various element combinations of the existing compounds and revealed all element combinations not yet realized in the synthesis within this compound class. Finally, we have analyzed the quasicrystal compound category as an example of a compound class that is not defined by a specific element combination or a molecular structure. PMID:24551517

Barth, Andreas; Marx, Werner

2012-01-01

311

Stimulation of Ideas through Compound-Based Bibliometrics: Counting and Mapping Chemical Compounds for Analyzing Research Topics in Chemistry, Physics, and Materials Science.  

PubMed

Counting compounds (rather than papers or citations) offers a new perspective for quantitative analyses of research activities. First of all, we can precisely define (compound-related) research topics and access the corresponding publications (scientific papers as well as patents) as a measure of research activity. We can also establish the time evolution of the publications dealing with specific compounds or compound classes. Moreover, the mapping of compounds by establishing compound-based landscapes has some potential to visualize the compound basis of research topics for further research activities. We have analyzed the rare earth compounds to give an example of a broad compound class. We present the number of the currently existing compounds and of the corresponding publications as well as the time evolution of the papers and patents. Furthermore, we have analyzed the rare earth cuprates (copper oxides) as an example of a narrower compound class to demonstrate the potential of mapping compounds by compound-based landscapes. We have quantified the various element combinations of the existing compounds and revealed all element combinations not yet realized in the synthesis within this compound class. Finally, we have analyzed the quasicrystal compound category as an example of a compound class that is not defined by a specific element combination or a molecular structure. PMID:24551517

Barth, Andreas; Marx, Werner

2012-12-01

312

Chemical characterization and mutagenic properties of polycyclic aromatic compounds in sediment from tributaries of the Great Lakes  

USGS Publications Warehouse

Sediments from four inshore industrial sites and a reference site in the Great Lakes were extracted with solvents and characterized chemically for polycyclic aromatic compounds (PACs). An aqueous phase and a crude organic extract were obtained. The crude organic extract was further resolved into fractions A-2 (polycyclic aromatic hydrocarbons) and A-3 (nitrogen-containing polycyclic aromatic compounds), which were analyzed for PACs by gas chromatography and gas chromatography-mass spectrometry. The extracts and fractions were tested for mutagenicity in three assays: Ames, rat hepatocyte unscheduled DNA synthesis, and Chinese hamster ovary hypoxanthine-guanine phosphoribosyl transferase (CHO/HGPRT). Sediments from the industrial sites contained 27 to 363 I?g/g total PACs; the reference site, less than 1 I?g/g. Qualitative differences in the residue profiles among the sites were attributable to the probable sources of the PACs (petroleum versus combustion). Only one industrial site yielded measurable (0.1 I?g/g or more) concentrations of individual nitrogen-containing PACs. In the Ames assay, only the highest doses of the A-2 fractions from two sites approached positive results. Conversely, the crude organic extract and A-2 and A-3 fractions from all sites induced unscheduled DNA synthesis. Crude organic extracts and the A-2 and A-3 fractions from all industrial sites gave well-defined dose-response relations in the CHO/HGPRT assay. We established the presence of chemical mutagens in sediment that could be correlated with neoplasms in fish from many of the sites; however, the mutagenicity of the sediment extracts was not completely related to the degree of contamination by PACs. We also discuss the utility of mutagenicity assays in the evaluation of complex chemical mixtures and the presence of potential interfering chemicals.

Fabacher, David L.; Schmitt, Christopher J.; Besser, John M.; Mac, Michael J.

1988-01-01

313

Antidepressant-like and anxiolytic-like effects of cannabidiol: a chemical compound of Cannabis sativa.  

PubMed

Anxiety and depression are pathologies that affect human beings in many aspects of life, including social life, productivity and health. Cannabidiol (CBD) is a constituent non-psychotomimetic of Cannabis sativa with great psychiatric potential, including uses as an antidepressant-like and anxiolytic-like compound. The aim of this study is to review studies of animal models using CBD as an anxiolytic-like and antidepressant-like compound. Studies involving animal models, performing a variety of experiments on the above-mentioned disorders, such as the forced swimming test (FST), elevated plus maze (EPM) and Vogel conflict test (VCT), suggest that CBD exhibited an anti-anxiety and antidepressant effects in animal models discussed. Experiments with CBD demonstrated non-activation of neuroreceptors CB1 and CB2. Most of the studies demonstrated a good interaction between CBD and the 5-HT1A neuro-receptor. PMID:24923339

de Mello Schier, Alexandre R; de Oliveira Ribeiro, Natalia P; Coutinho, Danielle S; Machado, Sergio; Arias-Carrión, Oscar; Crippa, Jose A; Zuardi, Antonio W; Nardi, Antonio E; Silva, Adriana C

2014-01-01

314

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

PubMed

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

Rodríguez Mellado, J M; Ruiz Montoya, M

1994-01-16

315

Attomole detection of isotope-labeled compounds in chemical defense research  

Microsoft Academic Search

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

J. S. Vogel; B. A. Buchholz; N. H. Pawley; R. E. Mauthe; K. Dingley; K. Turteltaub

1996-01-01

316

Chemical oxidation of volatile and semi-volatile organic compounds in soil  

SciTech Connect

Subsurface contamination with fuel hydrocarbons or chlorinated hydrocarbons is prevalent throughout the Department of Energy (DOE) complex and in many sites managed by the Environmental Protection Agency (EPA) Superfund program. The most commonly reported chlorinated hydrocarbons (occurring > 50% of DOE contaminated sites) were trichloroethylene (TCE), 1, 1, 1,-trichloroethane (TCA), and tetrachloroethylene (PCE) with concentrations in the range of 0.2 {mu}g/kg to 12,000 mg/kg. The fuel hydrocarbons most frequently reported as being present at DOE sites include aromatic compounds and polyaromatic compounds such as phenanthrene, pyrene, and naphthalene. The primary sources of these semi-volatile organic compounds (SVOCs) are coal waste from coal fired electric power plants used at many of these facilities in the past and gasoline spills and leaks. Dense non-aqueous phase liquids (DNAPLs) can migrate within the subsurface for long periods of time along a variety of pathways including fractures, macropores, and micropores. Diffusion of contaminants in the non-aqueous, aqueous, and vapor phase can occur from the fractures and macropores into the matrix of fine-textured media. As a result of these contamination processes, removal of contaminants from the subsurface and the delivery of treatment agents into and throughout contaminated regions are often hindered, making rapid and extensive remediation difficult.

Gates, D.D.; Siegrist, R.L.; Cline, S.R.

1995-06-01

317

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

E-print Network

terephthalate (PET) bottles: A source of controversy reviewed Cristina Bach a,b, *, Xavier Dauchy a , Marie to restrictions and/or specifications according to their toxicological data. Despite this, the analysis of PET and additives. Genotoxic and estrogenic activities in PET-bottled water have been reported. Chemical mixtures

Short, Daniel

318

DESI-MS\\/MS of Chemical Warfare Agents and Related Compounds  

Microsoft Academic Search

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 \\

Paul A. D'Agostino

2011-01-01

319

Linking gene regulation and the exo-metabolome: A comparative transcriptomics approach to identify genes that impact on the production of volatile aroma compounds in yeast  

PubMed Central

Background 'Omics' tools provide novel opportunities for system-wide analysis of complex cellular functions. Secondary metabolism is an example of a complex network of biochemical pathways, which, although well mapped from a biochemical point of view, is not well understood with regards to its physiological roles and genetic and biochemical regulation. Many of the metabolites produced by this network such as higher alcohols and esters are significant aroma impact compounds in fermentation products, and different yeast strains are known to produce highly divergent aroma profiles. Here, we investigated whether we can predict the impact of specific genes of known or unknown function on this metabolic network by combining whole transcriptome and partial exo-metabolome analysis. Results For this purpose, the gene expression levels of five different industrial wine yeast strains that produce divergent aroma profiles were established at three different time points of alcoholic fermentation in synthetic wine must. A matrix of gene expression data was generated and integrated with the concentrations of volatile aroma compounds measured at the same time points. This relatively unbiased approach to the study of volatile aroma compounds enabled us to identify candidate genes for aroma profile modification. Five of these genes, namely YMR210W, BAT1, AAD10, AAD14 and ACS1 were selected for overexpression in commercial wine yeast, VIN13. Analysis of the data show a statistically significant correlation between the changes in the exo-metabome of the overexpressing strains and the changes that were predicted based on the unbiased alignment of transcriptomic and exo-metabolomic data. Conclusion The data suggest that a comparative transcriptomics and metabolomics approach can be used to identify the metabolic impacts of the expression of individual genes in complex systems, and the amenability of transcriptomic data to direct applications of biotechnological relevance. PMID:18990252

Rossouw, Debra; Naes, Tormod; Bauer, Florian F

2008-01-01

320

Automated liquid chromatographic compound class group-type separation of crude oils and bitumens using chemically bonded aminosilane  

SciTech Connect

A rapid, automated high-performance liquid chromatographic (HPLC) system has been developed for the semipreparative separations of crude oils, bitumens, and related materials into either compound class group-type fractions (saturate, aromatic, and polar) or aromatic ring-number fractions (saturate, mono-, di-, tri-, and polyaromatic, and polar). Separations are performed with commercially available HPLC components and chemically bonded silica-NH/sub 2/ columns. The reproducibility in the quantitative data obtained from the method is excellent for crude and process oils with an average percent deviation of approximately 2% for any compound class group-type fractions. The importance of molecular structure and substituent effects on the separation of aromatic hydrocarbons according to the number of aromatic rings was determined by using 57 model compounds typically found in fossil fuels. The degree of overlap between aromatic ring-number fractions is minimal using the method as assessed by gas chromatographic/mass spectrometric Z series analyses of each ring-number fraction obtained from a highly aromatic crude oil.

Grizzle, P.L.; Sablotny, D.M.

1986-10-01

321

Attomole detection of isotope-labeled compounds in chemical defense research  

SciTech Connect

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`.

Vogel, J.S.; Buchholz, B.A.; Pawley, N.H.; Mauthe, R.E.; Dingley, K.; Turteltaub, K.

1996-11-01

322

Chemical synthesis of battery grade super-iron barium and potassium Fe(VI) ferrate compounds  

Microsoft Academic Search

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 K2FeO4 are presented. Synthetic pathways yielding 80–100g of 96.5–99.5% pure K2FeO4

Stuart Licht; Vera Naschitz; Bing Liu; Susanta Ghosh; Nadezhda Halperin; Leonid Halperin; Dmitri Rozen

2001-01-01

323

[Experience in the use of chemical compounds for the primary identification and differentiation of enteroviruses].  

PubMed

Data on the usage of chemical inhibitors nifan and belvtazid, which possess a selective and antienteroviral effect, in the primary identification of enteroviruses and their differentiation into polio- and non-poliomyelytic ones isolated from human clinical materials or the environment by using the cell culture are presented in the article. The method is recommended for the practical use by the virology service in the diagnostics of enteroviral infections and in the identification of cytopathic agents isolated from the enviroment. PMID:12688219

Amvros'eva, T V; Votiakov, V I; Andreeva, O T; Kazinets, O N; Bogush, Z F; Sharko, R M; Kvacheva, Z B

2003-02-01

324

DESI-MS\\/MS of Chemical Warfare Agents and Related Compounds  

Microsoft Academic Search

\\u000a Solid phase microextraction (SPME) fibers were used to headspace ­sample chemical warfare agents and their hydrolysis products\\u000a from glass vials and glass vials containing spiked media, including Dacron swabs, office carpet, paper and fabric. The interface\\u000a of the Z-spray source was modified to permit safe introduction of the SPME fibers for desorption electrospray ionization mass\\u000a spectrometric (DESI-MS) analysis. A “dip

Paul A. D’Agostino

325

A review on botanical species and chemical compounds with appetite suppressing properties for body weight control.  

PubMed

As obesity has reached epidemic proportions, the management of this global disease is of clinical importance. The availability and popularity of natural dietary supplements for the treatment of obesity has risen dramatically in recent years. The purpose of this paper was to review the effect of commonly available over the counter plant-derived supplements used to suppress appetite for obesity control and management. The data were obtained from the electronic databases PubMed, SpringerLink, Google Scholar, ScienceDirect, and MEDLINE with full text (via EBSCOHost) and the databases were accessed during late 2012 - early January 2013. The botanical species discussed in this review include Camellia sinensis, Caralluma fimbriata, Citrus aurantium, Coleus forskohlii, Garcinia cambogia and Phaseolus vulgaris. This review found that many botanical species including crude extracts and isolated compounds from plants have been shown to provide potentially promising therapeutic effects including appetite control and weight loss. However, many of these crude extracts and compounds need to be further investigated to define the magnitude of the effects, optimal dosage, mechanisms of action, long term safety, and potential side effects. PMID:23666454

Astell, Katie J; Mathai, Michael L; Su, Xiao Q

2013-09-01

326

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...

327

Application of chemical vapor generation systems to deliver constant gas concentrations for in vitro exposure to volatile organic compounds.  

PubMed

Exposure to volatile organic compounds from outdoor air pollution is a major public health concern; however, there is scant information about the health effects induced by inhalation exposure to photochemical transformed products of primary emissions. In this study, we present a stable and reproducible exposure method to deliver ppm-ppb levels of gaseous standards in a humidified air stream for in vitro cell exposure through a direct air-liquid interface. Gaseous species were generated from a diffusion vial, and coupled to a gas-phase in vitro exposure system. Acrolein and methacrolein, which are major first-generation photochemical transformation products of 1,3-butadiene and isoprene, respectively, were selected as model compounds. A series of vapor concentrations (0.23-2.37 ppmv for acrolein and 0.68-10.7 ppmv for methacrolein) were investigated to characterize the exposure dose-response relationships. Temperature and the inner diameter of the diffusion vials are key parameters to control the evaporation rates and diffusion rates for the delivery of target vapor concentrations. Our findings suggest that this exposure method can be used for testing a wide range of atmospheric volatile organic compounds, and permits both single compound and multiple compound sources to generate mixtures in air. The relative standard deviations (%RSD) of output concentrations were within 10% during the 4-hour exposure time. The comparative exposure-response data allow us to prioritize numerous hazardous gas phase air pollutants. These identified pollutants can be further incorporated into air quality simulation models to better characterize the environmental health risks arising from inhalation of the photochemical transformed products. PMID:25359428

Lin, Ying-Hsuan; Sexton, Kenneth G; Jaspers, Ilona; Li, Ya-Ru; Surratt, Jason D; Vizuete, William

2014-11-19

328

Identifying and quantifying secondhand smoke in source and receptor rooms: logistic regression and chemical mass balance approaches.  

PubMed

Identifying and quantifying secondhand tobacco smoke (SHS) that drifts between multiunit homes is critical to assessing exposure. Twenty-three different gaseous and particulate measurements were taken during controlled emissions from smoked cigarettes and six other common indoor source types in 60 single-room and 13 two-room experiments. We used measurements from the 60 single-room experiments for (i) the fitting of logistic regression models to predict the likelihood of SHS and (ii) the creation of source profiles for chemical mass balance (CMB) analysis to estimate source apportionment. We then applied these regression models and source profiles to the independent data set of 13 two-room experiments. Several logistic regression models correctly predicted the presence of cigarette smoke more than 80% of the time in both source and receptor rooms, with one model correct in 100% of applicable cases. CMB analysis of the source room provided significant PM2.5 concentration estimates of all true sources in 9 of 13 experiments and was half-correct (i.e., included an erroneous source or missed a true source) in the remaining four. In the receptor room, CMB provided significant estimates of all true sources in 9 of 13 experiments and was half-correct in another two. PMID:23631597

Dacunto, P J; Cheng, K-C; Acevedo-Bolton, V; Jiang, R-T; Klepeis, N E; Repace, J L; Ott, W R; Hildemann, L M

2014-02-01

329

Applications of in situ Raman spectroscopy for identifying nickel hydroxide materials and surface layers during chemical aging.  

PubMed

The applications of in situ vibrational spectroscopy for identifying bulk and surface Ni(OH)2 are discussed. Raman spectra from ?- and ?-Ni(OH)2 samples immersed in water are generally similar to those collected from comparable dry samples. However, the Raman scattering intensities vary, and dry ?-Ni(OH)2 additionally exhibits a surface O-H stretching mode at 3690 cm(-1). Using in situ Raman spectroscopy, the spontaneous transformation of ?-Ni(OH)2 to ?-Ni(OH)2 in room-temperature water was monitored. Such transformations are conventionally performed in high-temperature alkaline media. An intralayer OH-diffusion model is proposed. Internal stresses at the ?/?-phase boundary caused shifted peaks, higher order vibrational modes, and a new water peak at 3520 cm(-1). We conclude that Raman spectroscopy may be applied to observe Ni(OH)2 materials in situ during chemical and electrochemical treatments. Such measurements provide information on the proportions of ?- and ?-Ni(OH)2 and their fine structural details with high sensitivity. PMID:24502243

Hall, David S; Lockwood, David J; Poirier, Shawn; Bock, Christina; MacDougall, Barry R

2014-03-12

330

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)

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.

Shonouda, Mourad L.

331

Organic Chemistry Jasperse Acid-Base Practice Problems A. Identify each chemical as either an "acid" or a "base" in the following reactions, and  

E-print Network

Organic Chemistry Jasperse Acid-Base Practice Problems A. Identify each chemical as either an "acid" or a "base" in the following reactions, and identify "conjugate" relationships. -You should have one acid the More Acidic for Each of the Following Pairs: Single Variable Problems 16. 17. 18. 19. 20. 21. O O O OH

Jasperse, Craig P.

332

Quantum chemical studies of candidate high energy density material compounds. Final report May 87-Aug 89  

SciTech Connect

This report describes the development and application of ab initio quantum chemical methods that are especially relevant to the study of high-energy density materials species. Two major quantum chemical program systems, MESA and BROOKLYN, have been developed during the tenure of this research effort. Each of these development efforts was performed, in large part, at the Ballistic Research Laboratory (BRL) and The John Hopkins University. Here we report the results of quantum studies on molecular systems that are thought to be relevant to high-energy density material research. These include detailed descriptions of the electronic excited states of He{sub 2} the energy loss mechanisms for the He-H{sub 2} systems, detailed structural studies data for a series of triborane species, and analysis of the stability of four-atom metal clusters with molecular formulae B{sub 2}Li{sub 2} and B{sub 2}Be{sub 2}, and a preliminary theoretical study of the energy storage potential of hydrogen halide-doped rare gas solids.

Adams, G.F.; Chabalowski, C.F.

1991-01-01

333

Gas Chromatography Analysis with Olfactometric Detection (GC-O) as a Useful Methodology for Chemical Characterization of Odorous Compounds  

PubMed Central

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

Brattoli, Magda; Cisternino, Ezia; Dambruoso, Paolo Rosario; de Gennaro, Gianluigi; Giungato, Pasquale; Mazzone, Antonio; Palmisani, Jolanda; Tutino, Maria

2013-01-01

334

Gas chromatography analysis with olfactometric detection (GC-O) as a useful methodology for chemical characterization of odorous compounds.  

PubMed

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

Brattoli, Magda; Cisternino, Ezia; Dambruoso, Paolo Rosario; de Gennaro, Gianluigi; Giungato, Pasquale; Mazzone, Antonio; Palmisani, Jolanda; Tutino, Maria

2013-01-01

335

Crystal chemical aspects of superconductivity in BaFe2As2 and related compounds  

NASA Astrophysics Data System (ADS)

BaFe2As2 is the parent compound of the 122-type iron arsenides.^1 Superconductivity can be induced by several kinds of doping^2-4 or by pressure.^5 It is widely accepted that superconductivity in iron arsenides is unconventional and a number of experiments agree with the s±-scenario.^6 The latter relies on Fermi surface nesting which depends on both the electron count and the lattice. However, the coincidence of doping and pressure effects on the structure of BaFe2As2 supports the role of the structure.^7 Another open issue is the co-existence of superconductivity and AF magnetic ordering. Our ^57Fe-M"ossbauer experiments with underdoped Ba0.8K0.2Fe2As2 (Tc = 24 K) revealed full magnetic splitting, which indicates such a co-existence.^8 Compounds like Sr2VO3FeAs (Tc = 37-45 K) are promising candidates for higher Tc, but their crystal chemistry is not yet understood. In non-superconducting Sr2CrO3FeAs, we have detected a non-stoichiometry of the Fe-site (Fe0.93(1)Cr0.07(1)) and C-type AF ordering of the Cr^3+-layers.^9 The Cr-doping of the FeAs layer is probably detrimental to superconductivity in Sr2CrO3FeAs, but a similar non-stoichiometry may play a vital role in Sr2VO3FeAs.-^1 M. Rotter, M. Tegel, I. Schellenberg, et al., Phys. Rev. B 78, 020503 (2008).^2 M. Rotter, M. Tegel, and D. Johrendt, Phys. Rev. Lett. 101, 107006 (2008).^3 S. Jiang, C. Wang, Z. Ren, et al., J. Phys.: Condens. Matter 21, 382203 (2009).^4 A. S. Sefat, R. Jin, M. A. McGuire, et al., Phys. Rev. Lett. 101, 117004 (2008).^5 P. L. Alireza, Y. T. C. Ko, J. Gillett, et al., J. Phys.: Condens. Matter 21, 012208 (2009).^6 I. Mazin, D. J. Singh, M. D. Johannes, et al., Phys. Rev. Lett. 101, 057003 (2008).^7 M. Rotter, M. Pangerl, M. Tegel, et al., Angew. Chem. Int. Ed. 47, 7949 (2008).^8 M. Rotter, M. Tegel, I. Schellenberg, et al., New J. Phys. 11, 025014 (2009).^9 M. Tegel, Y. Su, F. Hummel, et al., arXiv0911.0450.

Johrendt, Dirk

2010-03-01

336

Chemical molecular beam deposition of II VI binary and ternary compound films in a gas flow  

NASA Astrophysics Data System (ADS)

The paper presents results of an investigation of the growth process of large area (50 cm 2) CdSe, CdTe, ZnTe and Zn xCd 1-xTe(0 ? x ? 1) films by chemical molecular beam deposition in flowing H 2 and Ar from elementary sources of Cd, Zn, Se and Te. The molecular beam intensities I have been varied in the range of 10 13-10 15 cm -2 s -1. The condensation temperatures were 400 to 600°C. The influence of the molecular beam intensities ratio, over a wide range, namely 10 -2< I III VI<10, on the deposition rate, structure and resistivity of the films has been studied. The deposition rate and the thickness of films was varied over the range 0.2—2Å/s and 10 2-10 4Å, respectively.

Razykov, T. M.

1991-06-01

337

Quantum chemical modeling of the inhibition mechanism of monoamine oxidase by oxazolidinone and analogous heterocyclic compounds.  

PubMed

Monoamine oxidase (MAO, EC 1.4.3.4) is responsible from the oxidation of a variety of amine neurotransmitters. MAO inhibitors are used for the treatment of depression or Parkinson's disease. They also inhibit the catabolism of dietary amines. According to one hypothesis, inactivation results from the formation of a covalent adduct to a cysteine residue in the enzyme. If the adduct is stable enough, the enzyme is inhibited for a long time. After a while, enzyme can turn to its active form as a result of adduct breakdown by ?-elimination. In this study, the proposed inactivation mechanism was modeled and tested by quantum chemical calculations. Eight heterocyclic methylthioamine derivatives were selected to represent the proposed covalent adducts. Activation energies related to their ?-elimination reactions were calculated using ab initio and density functional theory methods. Calculated activation energies were in good agreement with the relative stabilities of the hypothetical adducts predicted in the literature by enzyme inactivation measurements. PMID:23323992

Erdem, Safiye Sa?; Özp?nar, Gül Alt?nba?; Boz, Ümüt

2014-02-01

338

Organic honey from Trás-Os-Montes region (Portugal): chemical, palynological, microbiological and bioactive compounds characterization.  

PubMed

At the present time, the quality, integrity, sanitation and nutritional value of honeys receive attention on an international level due to the increasing content of chemicals in the aforementioned matrix. This work was conducted to evaluate the quality of 75 organic honey samples from the Trás-Os-Montes region (Portugal). Mean values obtained for physico-chemical parameters were: pH 3.7; 15.6% moisture; 0.26mS/cm electrical conductivity; 0.25% ash; 1.1mg/kg HMF; 15.3 Gothe diastase activity; 40.3meq/kg free acidity; 67.8% invert sugars and 2.7% apparent sucrose. All honey samples can be classified as monofloral Erica sp., as showed by pollen features. The amounts of phenols and flavonoids in the samples were also determined. In respect to sanitary quality (fecal coliforms) and safety (sulfite-reducing clostridia and Salmonella), all organic honey samples were negative. Furthermore, yeast and molds were detected in low counts, with mean values obtained of 5.5cfu/g and the value of total aerobic mesophiles obtained from honeys was established in 1.3×10(2)cfu/g±7.5×10(1)cfu/g. The levels of flavonoids had a stronger impact on both mesophiles (p=0.0004) and molds (p=0.0138) than the sucrose concentration (p=0.001 and 0.0278; respectively). The results reported in this study should be introduced in the organic honey label, and may help beekeepers, the industry, researchers and consumers better understand honey properties. PMID:22019893

Estevinho, Leticia M; Feás, Xesús; Seijas, Julio A; Pilar Vázquez-Tato, M

2012-02-01

339

Spectroscopic Studies of Azide compounds: Thermochemistry, Chemical Kinetics and Photodissociation Dynamics  

NASA Astrophysics Data System (ADS)

Some of the most difficult chemical systems, either to observe or produce in significant quantities, are polynitrogen molecules. One example of this type of molecules in the early stages of investigation is cyclic-N3, whose molecular geometry and promising technological applications have attracted our attention to define optimal experimental conditions for being photoproduced. High-resolution synchrotron-radiation-based Photoionization Mass Spectrometry (PIMS) was applied to study the dissociative photoionization of three azide precursors for cyclic-N3; chlorine azide (ClN3), hydrogen azide (HN3), and methyl azide (CH3N3). In our attempts to detect cyclic-N3, the thermochemistry derived in the PIMS studies stimulated our work to perform photodissociation dynamics experiments of CH3N3 at 193 nm using Photofragment Translational Spectroscopy (PTS) with electron impact (EI) detection under collision-free conditions, and chemical kinetic studies based on Infrared Spectroscopy (IR) in matrix-isolated ices formed from rare gases (Argon, Nitrogen and Xenon). PTS experiments lead us to derive the branching ratio between reactions CH 3+N3 (radical channel) vs CH3N+N2 (molecular channel), and to conclude that cyclic-N3 is the dominant product in the radical channel. In contrast, in the matrix isolation experiments we found no evidence of the radical channel, possibly due to barrier-less recombination. However, since no mechanistic reports of methyl azide dissociation exist at these conditions, these studies could have significant implications for future experiments addressed to detect cylic-N3 under matrix environments.

Quinto Hernandez, Alfredo

340

Antiviral activity of chemical compound isolated from Artemisia morrisonensis against hepatitis B virus in vitro.  

PubMed

The compound p-hydroxyacetophenone (PHAP) isolated from Artemisia morrisonensis was found to have potential anti-HBV effects in HepG2 2.2.15 cells. We clarified its antiviral mode further and HBV-transfected Huh7 cells were used as the platform. During viral gene expression, treatment with PHAP had no apparent effects on the viral precore/pregenomic RNA. However, the 2.4-kb preS RNA of viral surface gene increased significantly relative to the 2.1-kb S RNA with PHAP. Promoter activity analysis demonstrated that PHAP had a potent effect on augmenting the viral preS promoter activity. The subsequent increase in the large surface protein and induce endoplasmic reticular (ER) stress has been reported previously. Interestingly, PHAP specifically reduced ER stress related GRP78 RNA/protein levels, but not those of GRP94, in treated Huh7 cells while PHAP also led to the significant intracellular accumulation of virus. Moreover, treatment with the ER chaperone inducer thapsigargin relieved the inhibitory effect of PHAP based on the supernatant HBV DNA levels of HBV-expressed cells. In conclusion, this study suggests that the mechanism of HBV inhibition by PHAP might involve the regulation of viral surface gene expression and block virion secretion by interference with the ER stress signaling pathway. PMID:24269476

Huang, Tsurng-Juhn; Liu, Shu-Heng; Kuo, Yu-Cheng; Chen, Chia-Wen; Chou, Shen-Chieh

2014-01-01

341

Chemical Stabilization of Soil Organic Nitrogen by Phenolic Lignin Compounds in Anaerobic Agrosystems  

NASA Astrophysics Data System (ADS)

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.

Olk, D. C.

2004-12-01

342

Novel compound heterozygous mutations in the MYO15A gene in autosomal recessive hearing loss identified by whole-exome sequencing  

PubMed Central

Background Inherited genetic defects play an important role in congenital hearing loss, contributing to about 60% of deafness occurring in infants. Hereditary nonsyndromic hearing loss is highly heterogeneous, and most patients with a presumed genetic etiology lack a specific molecular diagnosis. Methods By whole exome sequencing, we identified responsible gene of family 4794 with autosomal recessively nonsyndromic hearing loss (ARNSHL). We also used DNA from 56 Chinese familial patients with ARNSHL (autosomal recessive nonsyndromic hearing loss) and 108 ethnicity-matched negative samples to perform extended variants analysis. Results We identified MYO15A c.IVS25?+?3G?>?A and c.8375 T?>?C (p.V2792A) as the disease-causing mutations. Both mutations co-segregated with hearing loss in family 4794, but were absent in the 56 index patients and 108 ethnicity-matched controls. Conclusions Our results demonstrated that the hearing loss of family 4794 was caused by novel compound heterozygous mutations in MYO15A. PMID:24206587

2013-01-01

343

Chemical synthesis of battery grade super-iron barium and potassium Fe(VI) ferrate compounds  

NASA Astrophysics Data System (ADS)

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.

Licht, Stuart; Naschitz, Vera; Liu, Bing; Ghosh, Susanta; Halperin, Nadezhda; Halperin, Leonid; Rozen, Dmitri

344

Evaluation of an evanescent fiber optic chemical sensor for monitoring aqueous volatile organic compounds  

SciTech Connect

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.

Blair, D.S.

1997-04-01

345

Data Analysis of Multi-Laser Standoff Spectral identification of chemical and biological compounds  

SciTech Connect

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.

Farahi, R H [ORNL; Zaharov, Viktor [ORNL; Tetard, Laurene [ORNL; Thundat, Thomas George [ORNL; Passian, Ali [ORNL

2013-01-01

346

*These substances include metals, polynuclear aromatic hydrocarbons, volatile organic compounds, polychlorinated biphenyls, and petroleum. Areas on which these substances have been identified and other areas where historical releases of these substances m  

E-print Network

*These substances include metals, polynuclear aromatic hydrocarbons, volatile organic compounds, polychlorinated biphenyls, and petroleum. Areas on which these substances have been identified and other areas where historical releases of these substances may have occurred were the subject of the investigation

Netoff, Theoden

347

Multivariate statistical approach to identify significant sources influencing the physico-chemical variables in Aerial Bay, North Andaman, India.  

PubMed

Aerial Bay is one of the harbor towns of Andaman and Nicobar Islands, the union territory of India. Nevertheless, it is least studied marine environment, particularly for physico-chemical assessment. Therefore, to evaluate the annual spatiotemporal variations of physico-chemical parameters, seawater samples collected from 20 sampling stations covering three seasons were analyzed. Multivariate statistics is applied to the investigated data in an attempt to understand the causes of variation in physico-chemical parameters. Cluster analysis distinguished mangrove and open sea stations from other areas by considering distinctive physico-chemical characteristics. Factor analysis revealed 79.5% of total variance in physico-chemical parameters. Strong loading included transparency, TSS, DO, BOD, salinity, nitrate, nitrite, inorganic phosphate, total phosphorus and silicate. In addition, box-whisker plots and Geographical Information System based land use data further facilitated and supported multivariate results. PMID:24981105

Jha, Dilip Kumar; Vinithkumar, N V; Sahu, Biraja Kumar; Das, Apurba Kumar; Dheenan, P S; Venkateshwaran, P; Begum, Mehmuna; Ganesh, T; Prashanthi Devi, M; Kirubagaran, R

2014-08-15

348

National Inventory of Alkylphenol Ethoxylate Compounds in U.S. Sewage Sludges and Chemical Fate in Outdoor Soil Mesocosms  

PubMed Central

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

Venkatesan, Arjun K.; Halden, Rolf U.

2012-01-01

349

Covalent attachment of Candida rugosa lipase on chemically modified hybrid matrix of polysiloxane-polyvinyl alcohol with different activating compounds.  

PubMed

Candida rugosa lipase was immobilized by covalent binding on hybrid matrix of polysiloxane-polyvinyl alcohol chemically modified with different activating agents as glutaraldehyde, sodium metaperiodate and carbonyldiimidazole. The experimental results suggested that functional activating agents render different interactions between enzyme and support, producing consequently alterations in the optimal reaction conditions. Properties of the immobilized systems were assessed and their performance on hydrolytic and synthetic reactions were evaluated and compared with the free enzyme. In hydrolytic reactions using p-nitrophenyl palmitate as substrate all immobilized systems showed higher thermal stability and optima pH and temperature values in relation to the free lipase. Among the activating compounds, carbonyldiimidazole resulted in a total recovery of activity on the support and the highest thermal stability. For the butyl butyrate synthesis, the best performance (molar conversion of 95% and volumetric productivity of 2.33 g L(-1)h(-1)) was attained with the lipase immobilized on POS-PVA activated with sodium metaperiodate. The properties of the support and immobilized derivatives were also evaluated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopies and chemical composition (FTIR). PMID:17889514

Santos, Julio C; Mijone, Patrícia D; Nunes, Gisele F M; Perez, Victor H; de Castro, Heizir F

2008-02-15

350

Distribution of chemical compounds observed in the UTLS during the TACTS campaign using the HALO aircraft  

NASA Astrophysics Data System (ADS)

The SPURT (Spurenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region) campaign was the first systematic observational study of extratropical Upper Troposphere / Lower Stratosphere (UTLS) seasonality. A clear seasonality of the composition in and air mass transport into the lowermost stratosphere (LMS) was found. In particular the composition of the LMS showed a sharp transition between July and October. In the course of the summer the LMS is flushed with very young air indicating air mass transport via the tropical pathway. For further investigation of these findings the TACTS (Transport and Composition in the UT/LMS) campaign was designed to improve our understanding of transport timescales, compositions and pathways in the UTLS region during the transition between mid-summer and fall. In order to cover the seasonal transition, TACTS was flown in conjunction with the ESMVal (Earth System Model Validation) mission in late August and September 2012 using the new German research aircraft HALO (The High Altitude and LOng Range Research Aircraft). The TACTS payload with 13 different instruments measuring a wide range of chemical tracers with different lifetimes and different source-sink characteristics provides additional information compared to the SPURT dataset (e.g. very short-lived (VSLS) halocarbons). We will present a comparison between the SPURT dataset and the in-situ measurements during the TACTS campaign. The main focus will be on a comparison of the observed distribution of nitrous oxide (N2O), water vapour, ozone and mean age derived from sulfurhexafluoride (SF6) as function of equivalent latitude and potential temperature. Also comparison of Tracer-Tracer correlations will be shown. Furthermore we discuss the additional information on transport timescale in the LMS provided by the measurements of very short-lived (VSLS) halocarbons.

Keber, Timo; Boenisch, Harald; Engel, Andreas; Hoor, Peter; Bozem, Heiko; Müller, Stefan; Zahn, Andreas; Krämer, Martina; Spelten, Nicole

2014-05-01

351

The TSCA Interagency Testing Committee (ITC) proposed strategy for identifying and coordinating U.S. government data needs for endocrine-disrupting chemicals  

SciTech Connect

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.

Walker, J.D. [ITC, Washington, DC (United States)

1995-12-31

352

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

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.

Lyford, Forest P.; Willey, Richard E.; Clifford, Scott

2000-01-01

353

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)

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.

Chambon, J. C.; Damgaard, I.; Jeannottat, S.; Hunkeler, D.; Broholm, M. M.; Binning, P. J.; Bjerg, P. L.

2012-12-01

354

Discovery of Compounds Blocking the Proliferation of Toxoplasma gondii and Plasmodium falciparum in a Chemical Space Based on Piperidinyl-Benzimidazolone Analogs  

PubMed Central

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

Saidani, Nadia; Botte, 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-Francois; Mercier, Corinne; Vial, Henri; Lopez, Roman

2014-01-01

355

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...

356

Atherosclerotic Risks from Chemicals: Part II. A RASH Analysis of In Vitro and In Vivo Bioassay Data to Evaluate 45 Potentially Hazardous Compounds  

Microsoft Academic Search

.   As reviewed in the Part I companion manuscript by Basavaraju and Jones (Arch Environ Contam Toxicol), atherosclerosis and\\u000a carcinogenesis may share some common mechanisms of toxicological action. On that hypothesis, standardized test data taken\\u000a from the Registry of Toxic Effects of Chemical Substances (RTECS) were used to compute relative potency factors for chemical\\u000a compounds associated with increased risk of

T. D. Jones; M. D. Morris; S. R. Basavaraju

1998-01-01

357

Compounds from the roots of Jasminum sambac.  

PubMed

Four new compounds (+)-jasminoids A, B, C, and D, together with seven known compounds, were isolated from the roots of Jasminum sambac. Their structures were identified using spectroscopic methods. This study provides a better understanding to the chemical composition of J. sambac roots that have been thought to be one ingredient of an ancient prescription 'Ma-Fei-San'. PMID:23134371

Zeng, Lin-Hong; Hu, Min; Yan, Yong-Ming; Lu, Qing; Cheng, Yong-Xian

2012-01-01

358

40 CFR 721.9668 - Organotin lithium compound.  

Code of Federal Regulations, 2011 CFR

...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...

2011-07-01

359

40 CFR 721.9668 - Organotin lithium compound.  

Code of Federal Regulations, 2012 CFR

...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...

2012-07-01

360

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...Substances § 721.9668 Organotin lithium compound. (a) Chemical substance...generically identified as an organotin lithium compound (PMN P-93-1119) is...

2010-07-01

361

40 CFR 721.9668 - Organotin lithium compound.  

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

362

Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part A): tropospheric degradation of non-aromatic volatile organic compounds  

Microsoft Academic Search

Kinetic and mechanistic data relevant to the tropospheric degradation of volatile organic compounds (VOC), and the production of secondary pollutants, have previously been used to define a protocol which underpinned the construction of a near-explicit Master Chemical Mechanism. In this paper, an update to the previous protocol is presented, which has been used to define degradation schemes for 107 non-aromatic

S. M. Saunders; M. E. Jenkin; R. G. Derwent; M. J. Pilling

2002-01-01

363

Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part A): tropospheric degradation of non-aromatic volatile organic compounds  

Microsoft Academic Search

Kinetic and mechanistic data relevant to the tropospheric degradation of volatile organic compounds (VOC), and the production of secondary pollutants, have previously been used to define a protocol which underpinned the construction of a near-explicit Master Chemical Mechanism. In this paper, an update to the previous protocol is presented, which has been used to define degradation schemes for 107 non-aromatic

S. M. Saunders; M. E. Jenkin; R. G. Derwent; M. J. Pilling

2003-01-01

364

Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part A): tropospheric degradation of non-aromatic volatile organic compounds  

Microsoft Academic Search

Kinetic and mechanistic data relevant to the tro- pospheric degradation of volatile organic compounds (VOC), and the production of secondary pollutants, have previously been used to define a protocol which underpinned the con- struction of a near-explicit Master Chemical Mechanism. In this paper, an update to the previous protocol is presented, which has been used to define degradation schemes for

S. M. Saunders; R. G. Derwent; M. J. Pilling

2003-01-01

365

Advances in X-Ray Chemical Analysis, Japan, 41 (2010) ISSN 0911-7806 Analysis of Compound Ratios of Titanium Dioxides with  

E-print Network

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

Jun, Kawai

366

Machine Learning of Molecular Electronic Properties in Chemical Compound Space Gregoire Montavon,1 Matthias Rupp,2 Vivekanand Gobre,3 Alvaro Vazquez-Mayagoitia,4 Katja  

E-print Network

Machine Learning of Molecular Electronic Properties in Chemical Compound Space Gr´egoire Montavon,1, Klaus-Robert M¨uller,1, 6, and O. Anatole von Lilienfeld4, 1Machine Learning Group, Technical that are synthetically accessible. Here, we present a machine learning (ML) model, trained on a data base of ab initio

367

Application of 31P NMR Spectroscopy and Chemical Derivatization for Metabolite Profiling of Lipophilic Compounds in Human Serum  

PubMed Central

New methods for obtaining metabolic fingerprints of biological samples with improved resolution and sensitivity are highly sought for early disease detection, studies of human health and pathophysiology, and for better understanding systems biology. Considering the complexity of biological samples, interest in biochemical class selection through the use of chemoselective probes for improved resolution and quantitation is increasing. Considering the role of lipids in the pathogenesis of a number of diseases, in this study fingerprinting of lipid metabolites was achieved by 31P labeling using the derivatizing agent 2-chloro-4,4,5,5-tetramethyldioxaphospholane. Lipids containing hydroxyl, aldehyde and carboxyl groups were selectively tagged with 31P and then detected with good resolution using 31P NMR by exploiting the 100% natural abundance and wide chemical shift range of 31P. After standardizing the reaction conditions using representative compounds, the derivatization approach was used to profile lipids in human serum. The results show that the 31P derivatization approach is simple, reproducible and highly quantitative, and has the potential to profile a number of important lipids in complex biological samples. PMID:19610016

DeSilva, M. Aruni; Shanaiah, Narasimhamurthy; Gowda, G. A. Nagana; Rosa-Perez, Kellymar; Hanson, Bryan A.; Raftery, Daniel

2010-01-01

368

Tubulin-dependent Hydrolysis of Guanosine Triphosphate as a Screening Test to Identify New Antitubulin Compounds with Potential as Antimitotic Agents: Application to Carbamates of Aromatic Amines  

Microsoft Academic Search

Tubulin-dependent GTP hydrolysis was evaluated for its potential as a relatively simple screening assay for newantimitotic drugs. Carbamates of aromatic amines were chosen as the test system because of the relatively diverse structures of compounds in this class already known to have antimitotic properties and because of the large number of such compounds in the NSC collection of the National

Chi Duanmu; Lilian K. Shahrik; Holly H. Ho; Ernest Hamel

369

Water-soluble organics in atmospheric particles: A critical review of the literature and application of thermodynamics to identify candidate compounds  

Microsoft Academic Search

Although organic compounds typically constitute a substantial fraction of the fine particulate matter (PM) in the atmosphere, their molecular composition remains poorly characterized. This is largely because atmospheric particles contain a myriad of diverse organic compounds, not all of which extract in a single solvent or elute through a gas chromatograph; therefore, a substantial portion typically remains unanalyzed. Most often

Pradeep Saxena; Lynn M. Hildemann

1996-01-01

370

Chemicals identified in feral and food animals: a data base. First annual report, October 1981. Volume I. Records 1-532  

SciTech Connect

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.

Cone, M.V.; Faust, R.A.; Baldauf, M.F. (comps.)

1981-12-01

371

A High-Resolution Genetic Map of Yellow Monkeyflower Identifies Chemical Defense QTLs and Recombination Rate Variation  

E-print Network

sequencing, we construct a dense linkage map for a panel of recombinant inbred lines derived from a cross between divergent ecotypes of Mimulus guttatus. We used this map to estimate recombination rate across the genome and to identify quantitative trait loci...

Holeski, Liza M.; Monnahan, Patrick; Koseva, Boryana S.; McCool, Nick; Lindroth, Richard L.; Kelly, John K.

2014-05-04

372

Chemical and biological methods for the analysis and remediation of environmental contaminants frequently identified at Superfund sites  

E-print Network

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...

Wiles, Melinda Christine

2004-11-15

373

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...

374

The use of a housecleaning product in an indoor environment leading to oxygenated polar compounds and SOA formation: Gas and particulate phase chemical characterization  

NASA Astrophysics Data System (ADS)

This work investigates Secondary Organic Aerosol (SOA) formed by limonene ozonolysis using a housecleaning product in indoor environment. This study combines simulation chamber ozonolysis experiments and field studies in an experimental house allowing different scenarios of housecleaning product use in real conditions. Chemical speciation has been performed using a new method based on simultaneous sampling of both gas and particulate phases on sorbent tubes and filters. This method allowed the identification and quantification of about 35 products in the gas and particulate phases. Among them, products known to be specific from limonene ozonolysis such as limononaldehyde, ketolimonene and ketolimonic acid have been detected. Some other compounds such as 2-methylbutanoic acid had never been detected in previous limonene ozonolysis studies. Some compounds like levulinic acid had already been detected but their formation remained unexplained. Potential reaction pathways are proposed in this study for these compounds. For each experiment, chemical data are coupled together with physical characterization of formed particles: mass and size and number distribution evolution which allowed the observation of new particles formation (about 87,000 particle cm-3). The chemical speciation associated to aerosol size distribution results confirmed that limonene emitted by the housecleaning product was responsible for SOA formation. To our knowledge, this work provides the most comprehensive analytical study of detected compounds in a single experiment for limonene ozonolysis in both gaseous and particulate phases in real indoor environment.

Rossignol, S.; Rio, C.; Ustache, A.; Fable, S.; Nicolle, J.; Même, A.; D'Anna, B.; Nicolas, M.; Leoz, E.; Chiappini, L.

2013-08-01

375

Identifying Water Main Leaks With Trihalomethane Tracers  

Microsoft Academic Search

In this study, the trihalomethanes (THMs) chloroform and dichlorobromomethane, present in chlorinated drinking water, were used as tracer compounds to identify the presence of treated city water in samples of seepage collected at leak sites in the distribution system. Using physical and chemical tests such as alkalinity, hardness, conductivity, and pH, the origin of leakage water samples often could not

Erika E. Hargesheimer

1985-01-01

376

The Antioxidant Defense System Keap1-Nrf2 Comprises a Multiple Sensing Mechanism for Responding to a Wide Range of Chemical Compounds? †  

PubMed Central

Animals have evolved defense systems for surviving in a chemically diverse environment. Such systems should demonstrate plasticity, such as adaptive immunity, enabling a response to even unknown chemicals. The antioxidant transcription factor Nrf2 is activated in response to various electrophiles and induces cytoprotective enzymes that detoxify them. We report here the discovery of a multiple sensing mechanism for Nrf2 activation using zebrafish and 11 Nrf2-activating compounds. First, we showed that six of the compounds tested specifically target Cys-151 in Keap1, the ubiquitin ligase for Nrf2, while two compounds target Cys-273. Second, in addition to Nrf2 and Keap1, a third factor was deemed necessary for responding to three of the compounds. Finally, we isolated a zebrafish mutant defective in its response to seven compounds but not in response to the remaining four. These results led us to categorize Nrf2 activators into six classes and hypothesize that multiple sensing allows enhanced plasticity in the system. PMID:19001094

Kobayashi, Makoto; Li, Li; Iwamoto, Noriko; Nakajima-Takagi, Yaeko; Kaneko, Hiroshi; Nakayama, Yuko; Eguchi, Masami; Wada, Yoshiko; Kumagai, Yoshito; Yamamoto, Masayuki

2009-01-01

377

Chemical composition and cytotoxicity evaluation of essential oil from leaves of Casearia sylvestris, its main compound ?-zingiberene and derivatives.  

PubMed

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

Bou, Diego Dinis; Lago, João Henrique G; Figueiredo, Carlos R; Matsuo, Alisson L; Guadagnin, Rafael C; Soares, Marisi G; Sartorelli, Patricia

2013-01-01

378

The chemical nature of phenolic compounds determines their toxicity and induces distinct physiological responses in Saccharomyces cerevisiae in lignocellulose hydrolysates.  

PubMed

We investigated the severity of the inhibitory effects of 13 phenolic compounds usually found in spruce hydrolysates (4-hydroxy-3-methoxycinnamaldehyde, homovanilyl alcohol, vanillin, syringic acid, vanillic acid, gallic acid, dihydroferulic acid, p-coumaric acid, hydroquinone, ferulic acid, homovanillic acid, 4-hydroxybenzoic acid and vanillylidenacetone). The effects of the selected compounds on cell growth, biomass yield and ethanol yield were studied and the toxic concentration threshold was defined for each compound. Using Ethanol Red, the popular industrial strain of Saccharomyces cerevisiae, we found the most toxic compound to be 4-hydroxy-3-methoxycinnamaldehyde which inhibited growth at a concentration of 1.8 mM. We also observed that toxicity did not generally follow a trend based on the aldehyde, acid, ketone or alcohol classification of phenolic compounds, but rather that other structural properties such as additional functional groups attached to the compound may determine its toxicity. Three distinctive growth patterns that effectively clustered all the compounds involved in the screening into three categories. We suggest that the compounds have different cellular targets, and that. We suggest that the compounds have different cellular targets and inhibitory mechanisms in the cells, also compounds who share similar pattern on cell growth may have similar inhibitory effect and mechanisms of inhibition. PMID:24949277

Adeboye, Peter Temitope; Bettiga, Maurizio; Olsson, Lisbeth

2014-01-01

379

A chemical genetic screen in Mycobacterium tuberculosis identifies carbon-source-dependent growth inhibitors devoid of in vivo efficacy  

PubMed Central

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

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

380

Development of a Fission Yeast-Based High-Throughput Screen to Identify Chemical Regulators of cAMP Phosphodiesterases  

Microsoft Academic Search

Cyclic nucleotide phosphodiesterases (PDEs) comprise a superfamily of enzymes that serve as drug targets in many human diseases. There is a continuing need to identify high-specificity inhibitors that affect individual PDE families or even subtypes within a single family. The authors describe a fission yeast-based high-throughput screen to detect inhibitors of heterologously expressed adenosine 3?,5?-cyclic monophosphate (cAMP) PDEs. The utility

F. Douglas Ivey; Lili Wang; Didem Demirbas; Christina Allain; Charles S. Hoffman

2008-01-01

381

Fisher ratio method applied to third-order separation data to identify significant chemical components of metabolite extracts  

SciTech Connect

This report is about applying a Fisher ratio method to entire four dimensional (4D) data sets from third-order instrumentation data. The Fisher ratio method uses a novel indexing scheme to discover the unknown chemical differences among known classes of complex samples. This is the first report of a Fisher ratio analysis procedure applied to entire 4D data sets of third-order separation data, which, in this case, is comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry analyses of metabolite extracts using all of the collected mass channels. Current analysis methods for third-order separation data use only userdefined subsets of the 4D data set.

Pierce, Karisa M.; Hoggard, Jamin C.; Hope, Janiece L.; Rainey, Petrie M.; Hoofnagle, Andrew N.; Jack, Rhona M.; Wright, Bob W.; Synovec, Robert E.

2006-07-15

382

Mortality study of workers in 1,3-butadiene production units identified from a chemical workers cohort.  

PubMed Central

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

Ward, E M; Fajen, J M; Ruder, A M; Rinsky, R A; Halperin, W E; Fessler-Flesch, C A

1995-01-01

383

Mortality study of workers employed in 1,3-butadiene production units identified from a large chemical workers cohort.  

PubMed

The IARC 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, a cohort mortality study was conducted 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 and Institute 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% confidence interval (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. A statistically non-significant excess of stomach cancer was observed in the overall cohort (five cases; SMR = 243; CI = 79-568) that was most pronounced among workers employed in the Rubber Reserve plant for 2 or more years (five cases; SMR = 657; CI = 213-1530). We conclude that the results of this study add to the weight of evidence suggesting that butadiene is carcinogenic in humans. PMID:8901895

Ward, E M; Fajen, J M; Ruder, A M; Rinsky, R A; Halperin, W E; Fessler-Flesch, C A

1996-10-28

384

Mortality study of workers in 1,3-butadiene production units identified from a chemical workers cohort.  

PubMed

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

Ward, E M; Fajen, J M; Ruder, A M; Rinsky, R A; Halperin, W E; Fessler-Flesch, C A

1995-06-01

385

Establishment and validation of whole-cell based fluorescence assays to identify anti-mycobacterial compounds using the Acanthamoeba castellanii-Mycobacterium marinum host-pathogen system.  

PubMed

Tuberculosis is considered to be one of the world's deadliest disease with 2 million deaths each year. The need for new antitubercular drugs is further exacerbated by the emergence of drug-resistance strains. Despite multiple recent efforts, the majority of the hits discovered by traditional target-based screening showed low efficiency in vivo. Therefore, there is heightened demand for whole-cell based approaches directly using host-pathogen systems. The phenotypic host-pathogen assay described here is based on the monitoring of GFP-expressing Mycobacterium marinum during infection of the amoeba Acanthamoeba castellanii. The assay showed straight-forward medium-throughput scalability, robustness and ease of manipulation, demonstrating its qualities as an efficient compound screening system. Validation with a series of known antitubercular compounds highlighted the advantages of the assay in comparison to previously published macrophage-Mycobacterium tuberculosis-based screening systems. Combination with secondary growth assays based on either GFP-expressing D. discoideum or M. marinum allowed us to further fine-tune compound characterization by distinguishing and quantifying growth inhibition, cytotoxic properties and antibiotic activities of the compounds. The simple and relatively low cost system described here is most suitable to detect anti-infective compounds, whether they present antibiotic activities or not, in which case they might exert anti-virulence or host defense boosting activities, both of which are largely overlooked by classical screening approaches. PMID:24498207

Kicka, Sébastien; Trofimov, Valentin; Harrison, Christopher; Ouertatani-Sakouhi, Hajer; McKinney, John; Scapozza, Leonardo; Hilbi, Hubert; Cosson, Pierre; Soldati, Thierry

2014-01-01

386

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.  

PubMed

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 1mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs-Ringer-HEPES buffer at pH6.2 for 4h prior to reoxygenation at pH7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca(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(2+) uptake and suppressed the Ca(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(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. PMID:24012766

Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L; Smith, Charles D; Lemasters, John J

2013-11-15

387

Room temperature synthesis of nanostructured mixed-ordered-vacancy compounds (OVCs) and chalcopyrite CuInSe2 (CIS) thin films in alkaline chemical bath  

Microsoft Academic Search

Room temperature synthesis of ordered-vacancy-compounds (OVCs) and copper indium diselenide (CuInSe2, CIS) by cation and anion exchange reactions of solid CdS thin films with CIS ionic solution in an alkaline chemical bath is reported. The growth parameters such as pH, deposition time and concentration of the solutions were optimized to achieve uniform thin films. Nanostructured CdS thin films (150 nm

Ramphal Sharma; Rajaram S Mane; Gangri Cai Anil Ghule; Duk-Ho Ham; Sun-Ki Min; Seung-Eon Lee; Sung-Hwan Han

2009-01-01

388

Vertical Distribution of PhysicoChemical Properties and Number of Sulfur-Oxidizing Bacteria in the Buried Layer of Soil Profiles with Marine-Reduced Sulfur Compounds  

Microsoft Academic Search

We observed the presence of reduced sulfur compounds in the buried soil layer of a paddy field on Sado Island, Niigata Prefecture. We sampled the paddy field soil from 0 to 300 cm depth and analyzed the physico-chemical properties of the soil and the numbers of sulfur-oxidizing bacteria and iron-oxidizing bacteria in order to elucidate both the sulfur-oxidizing mechanism and

Hirotomo Ohba; Naoto Owa

2005-01-01

389

A SAW-based chemical sensor for detecting sulfur-containing organophosphorus compounds using a two-step self-assembly and molecular imprinting technology.  

PubMed

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

Pan, Yong; Yang, Liu; Mu, Ning; Shao, Shengyu; Wang, Wen; Xie, Xiao; He, Shitang

2014-01-01

390

The Origins of Light and Heavy R-process Elements Identified by Chemical Tagging of Metal-poor Stars  

NASA Astrophysics Data System (ADS)

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] gsim +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.

Tsujimoto, Takuji; Shigeyama, Toshikazu

2014-11-01

391

Towards habitat-oriented systems biology of "Aromatoleum aromaticum" EbN1: chemical sensing, catabolic network modulation and growth control in anaerobic aromatic compound degradation.  

PubMed

The denitrifying betaproteobacterium "Aromatoleum aromaticum" EbN1 is a well-studied model organism for anaerobic degradation of aromatic compounds. Following publication of its genome in 2005, comprehensive physiological-proteomic studies were conducted to deduce functional understanding from the genomic blueprint. A catabolic network (85 predicted, 65 identified proteins) for anaerobic degradation of 24 aromatic growth substrates (including 11 newly recognized) was established. Newly elucidated pathways include those for 4-ethylphenol and plant-derived 3-phenylpropanoids, involving functional assignment of several paralogous genes. The substrate-specific regulation of individual peripheral degradation pathways is probably initiated by highly specific chemical sensing via dedicated sensory/regulatory proteins, e.g. three different ???-dependent one-component sensory/regulatory proteins are predicted to discriminate between three phenolic substrates (phenol, p-cresol and 4-ethylphenol) and two different two-component systems are assumed to differentiate between two alkylbenzenes (toluene, ethylbenzene). Investigations under in situ relevant growth conditions revealed (a) preferred utilization of benzoate from a mixture with succinate results from repressed synthesis of a C?-dicarboxylate TRAP transporter; (b) response to alkylbenzene-induced solvent stress comprises metabolic re-routing of acetyl-CoA and reducing equivalents to poly(3-hydroxybutyrate) synthesis, alteration of cellular membrane composition and formation of putative solvent efflux systems; and (c) multifaceted adaptation to slow growth includes adjustment of energy demand for maintenance and preparedness for future nutritional opportunities, i.e. provision of uptake systems and catabolic enzymes for multiple aromatic substrates despite their absence. This broad knowledge base taken together with the recent development of a genetic system will facilitate future functional, biotechnological (stereospecific dehydrogenases) and habitat re-enacting ("eco-"systems biology) studies with "A. aromaticum" EbN1. PMID:24493567

Rabus, Ralf; Trautwein, Kathleen; Wöhlbrand, Lars

2014-04-01

392

The phytochemical and genetic survey of common and dwarf juniper (Juniperus communis and Juniperus nana) identifies chemical races and close taxonomic identity of the species.  

PubMed

Juniperus communis L. (= J. communis var. communis) and Juniperus nana Willd. (= J. communis var. SAXATILIS) are subspecies of juniper. J. communis grows widely in both hemispheres, primarily in lower elevations while J. nana is mainly observed in high mountains. Although they can be distinguished by morphological features, it is not known whether they are genetically and phytochemically distinct entities. We aimed to check whether it is possible to distinguish these two plants (i) by pharmaceutically important chemical traits and (ii) on the basis of intraspecifically highly polymorphic fragment of chloroplast DNA. We used GC with achiral as well as with enantioselective stationary phase columns to identify the main monoterpenes of the essential oil. Sequence analysis of the TRNL (UAA)- TRNF (GAA) intergenic spacer of the chloroplast genome was used as a genetic marker of taxonomic identity between these two subspecies. The chromatographic analysis showed the existence of three chemical races - the alpha-pinene type, the sabinene type and one with intermediate contents of these terpenes among both J. communis and J. nana. Surprisingly, sequence analysis of TRNL (UAA)- TRNF (GAA) revealed 100 % similarity between the common and the dwarf juniper. Thus, the monoterpene pattern is related to geographical origin, and not to the species identity. We suggest that the three chemical races identified in the present study should be considered as separate sources of pharmaceutical raw material. Our results demonstrate that the contents of alpha-pinene and sabinene may be applied as a quick diagnostic test for preliminary evaluation of plant material. PMID:16783703

Filipowicz, Natalia; Piotrowski, Arkadiusz; Ochocka, J Renata; Asztemborska, Monika

2006-07-01

393

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...

394

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...

395

The chemical and environmental property space of REACH chemicals.  

PubMed

The European regulation on chemicals, REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals), came into force on 1 June 2007. With pre-registration complete in 2008, data for these substances may provide an overview of the expected chemical space and its characteristics. In this paper, using various in silico computation tools, we evaluate 48782 neutral organic compounds from the list to identify hazardous and safe compounds. Two different classification schemes (modified Verhaar and ECOSAR) identified between 17% and 25% of the compounds as expressing only baseline toxicity (narcosis). A smaller portion could be identified as reactive (19%) or specifically acting (2.7%), while the majority were non-assigned (61%). Overall environmental persistence, bioaccumulation and long-range transport potential were evaluated using structure-activity relationships and a multimedia fugacity-based model. A surprisingly high proportion of compounds (20%), mainly aromatic and halogenated, had a very high estimated persistence (>195 d). The proportion of compounds with a very high estimated bioconcentration or bioaccumulation factor (>5000) was substantially less (6.9%). Finally, a list was compiled of those compounds within the applicability domain of the models used, meeting both persistence and bioaccumulation criteria, and with a long-range transport potential comparable to PCB. This list of 68 potential persistent organic pollutants contained many well-known compounds (all halogenated), but notably also five fluorinated compounds that were not included in the EINECS inventory. This study demonstrates the usability of in silico tools for identification of potentially environmentally hazardous chemicals. PMID:22386455

Öberg, Tomas; Iqbal, M Sarfraz

2012-05-01

396

Comparative mapping of soil physical-chemical and structural parameters at field scale to identify zones of enhanced leaching risk.  

PubMed

Preferential flow and particle-facilitated transport through macropores contributes significantly to the transport of strongly sorbing substances such as pesticides and phosphorus. The aim of this study was to perform a field-scale characterization of basic soil physical properties like clay and organic carbon content and investigate whether it was possible to relate these to derived structural parameters such as bulk density and conservative tracer parameters and to actual particle and phosphorus leaching patterns obtained from laboratory leaching experiments. Sixty-five cylindrical soil columns of 20-cm height and 20-cm diameter and bulk soil were sampled from the topsoil in a 15-m × 15-m grid in an agricultural loamy field. Highest clay contents and highest bulk densities were found in the northern part of the field. Leaching experiments with a conservative tracer showed fast 5% tracer arrival times and high tracer recovery percentages from columns sampled from the northern part of the field, and the leached mass of particles and particulate phosphorus was also largest from this area. Strong correlations were obtained between 5% tracer arrival time, tracer recovery, and bulk density, indicating that a few well-aligned and better connected macropores might change the hydraulic conductivity between the macropores and the soil matrix, triggering an onset of preferential flow at lower rain intensities compared with less compacted soil. Overall, a comparison mapping of basic and structural characteristics including soil texture, bulk density, dissolved tracer, particle and phosphorus transport parameters identified the northern one-third of the field as a zone with higher leaching risk. This risk assessment based on parameter mapping from measurements on intact samples was in good agreement with 9 yr of pesticide detections in two horizontal wells and with particle and phosphorus leaching patterns from a distributed, shallow drainage pipe system across the field. PMID:23673762

Norgaard, Trine; Moldrup, Per; Olsen, Preben; Vendelboe, Anders L; Iversen, Bo V; Greve, Mogens H; Kjaer, Jeanne; de Jonge, Lis W

2013-01-01

397

Chemical speciation and source apportionment of Non-Methane Volatile Organic Compounds (NMVOCs) in a Middle Eastern country  

NASA Astrophysics Data System (ADS)

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.

Salameh, Therese; Sauvage, Stéphane; Afif, Charbel; Borbon, Agnès; Locoge, Nadine

2014-05-01

398

Chemical Composition of Semivolatile Compounds and Organic Aerosol in a Pine Forest: Bulk and Speciated Measurements by In-situ TAG-AMS and Offline GCxGC/HRTOFMS at BEACHON-RoMBAS 2011  

NASA Astrophysics Data System (ADS)

Semivolatile organic compounds (SVOCs) represent an important source of organic aerosol (OA) in remote forested regions. Understanding their composition is essential to identifying their sources and processing, but the chemical complexity often limits such analysis. Here we present concurrent bulk and speciated measurements of semivolatile and particle-phase organic compounds using a novel combined instrument (TAG-AMS) at Manitou Forest, CO during the BEACHON-RoMBAS 2011 campaign. The Thermal desorption Aerosol Gas chromatograph (TAG) provides on-line organic speciation of ambient SVOCs with bihourly time resolution, while the AMS provides bulk mass spectral analysis of the concurrent OA sample. This deployment was a unique and experimental version of the TAG-AMS instrument, with a prototype filter cell designed to quantitatively collect and analyze SVOCs. The combined instrument provides quantitative measurements of organic and inorganic mass loadings, and elemental and PMF analysis of the bulk OA, simultaneously with detailed organic speciation of SVOCs. Additionally, filter samples are analyzed by comprehensive GCxGC/HR-TOF-MS to assist in compound identification by TAG. The system provided around-the-clock measurements for a 2-week period. Online and offline measurements reveal > 100 compounds, a subset of which is observed at a bihourly time resolution, and is used to identify the sources of organic aerosol in the region. Bihourly measurements of sesquiterpenes, which represent a major fraction of observed SVOCs, are used to investigate their emission sources and subsequent processing into OA. These observations are also compared to a previous study conducted at a similar pine forest in California.

Chan, A. W.; Kreisberg, N. M.; Zhao, Y.; Hohaus, T.; Campuzano Jost, P.; Teng, A.; Huang, I.; Jayne, J.; Worsnop, D. R.; Jimenez, J. L.; Hering, S. V.; Goldstein, A. H.

2012-12-01

399

Microscopic physical and chemical properties of graphite intercalation compounds. Final report, August 1, 1984--July 31, 1985  

SciTech Connect

Optical spectroscopy (Raman, FTIR and Reflection ) was used to study a variety of acceptor- and donor-type compounds synthesized to determine the microscopic models consistent with the spectrocsopic results. General finding is that the electrical conduction properties of these compounds can be understood on the basis that the intercalation of atomic and/or molecular species between the host graphite layers either raises or lowers the Fermi level (E{sub F)} in a graphitic band structure. This movement of E{sub F} is accomplished via a charge transfer of electrons from the intercalate layers to the graphitic layers (donor compounds), or vice versa (acceptor compounds). Furthermore, the band structure must be modified to take into account the layers of charge that occur as a result of the charge transfer. This charge layering introduces additional bands of states near E{sub F}, which are discussed. Charge-transfer also induces a perturbation of the graphitic normal mode frequencies which can be understood as the result of a contraction (acceptor compounds) or expansion (donor compounds) of the intralayer C-C bonds. Ab-initio calculations support this view and are in reasonable agreement with experimental data.

Eklund, P.C.

1992-08-24

400

The Development, Validation, and Use of Quantitative Structure Activity Relationship Models of 5-Hydroxytryptamine (2B) Receptor Ligands to Identify Novel Receptor Binders and Putative Valvulopathic Compounds among Common Drugs  

PubMed Central

Some antipsychotic drugs are known to cause valvular heart disease by activating serotonin 5-HT2B receptors. We have developed and validated binary classification QSAR models capable of predicting potential 5-HT2B binders. The classification accuracies of the models to discriminate 5-HT2B actives from the inactives were as high as 80% for the external test set. These models were used to screen in silico 59,000 compounds included in the World Drug Index and 122 compounds were predicted as actives with high confidence. Ten of them were tested in radioligand binding assays and nine were found active suggesting a success rate of 90%. All validated binders were then tested in functional assays and one compound was identified as a true 5-HT2B agonist. We suggest that the QSAR models developed in this study could be used as reliable predictors to flag drug candidates that are likely to cause valvulopathy. PMID:20958049

Hajjo, Rima; Grulke, Christopher; Golbraikh, Alexander; Setola, Vincent; Huang, Xi-Ping; Roth, Bryan L.; Tropsha, Alexander

2012-01-01