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1

Large-Scale Chemical Similarity Networks for Target Profiling of Compounds Identified in Cell-Based Chemical Screens  

PubMed Central

Target identification is one of the most critical steps following cell-based phenotypic chemical screens aimed at identifying compounds with potential uses in cell biology and for developing novel disease therapies. Current in silico target identification methods, including chemical similarity database searches, are limited to single or sequential ligand analysis that have limited capabilities for accurate deconvolution of a large number of compounds with diverse chemical structures. Here, we present CSNAP (Chemical Similarity Network Analysis Pulldown), a new computational target identification method that utilizes chemical similarity networks for large-scale chemotype (consensus chemical pattern) recognition and drug target profiling. Our benchmark study showed that CSNAP can achieve an overall higher accuracy (>80%) of target prediction with respect to representative chemotypes in large (>200) compound sets, in comparison to the SEA approach (60–70%). Additionally, CSNAP is capable of integrating with biological knowledge-based databases (Uniprot, GO) and high-throughput biology platforms (proteomic, genetic, etc) for system-wise drug target validation. To demonstrate the utility of the CSNAP approach, we combined CSNAP's target prediction with experimental ligand evaluation to identify the major mitotic targets of hit compounds from a cell-based chemical screen and we highlight novel compounds targeting microtubules, an important cancer therapeutic target. The CSNAP method is freely available and can be accessed from the CSNAP web server (http://services.mbi.ucla.edu/CSNAP/). PMID:25826798

Lo, Yu-Chen; Senese, Silvia; Li, Chien-Ming; Hu, Qiyang; Huang, Yong; Damoiseaux, Robert; Torres, Jorge Z.

2015-01-01

2

Large-scale chemical similarity networks for target profiling of compounds identified in cell-based chemical screens.  

PubMed

Target identification is one of the most critical steps following cell-based phenotypic chemical screens aimed at identifying compounds with potential uses in cell biology and for developing novel disease therapies. Current in silico target identification methods, including chemical similarity database searches, are limited to single or sequential ligand analysis that have limited capabilities for accurate deconvolution of a large number of compounds with diverse chemical structures. Here, we present CSNAP (Chemical Similarity Network Analysis Pulldown), a new computational target identification method that utilizes chemical similarity networks for large-scale chemotype (consensus chemical pattern) recognition and drug target profiling. Our benchmark study showed that CSNAP can achieve an overall higher accuracy (>80%) of target prediction with respect to representative chemotypes in large (>200) compound sets, in comparison to the SEA approach (60-70%). Additionally, CSNAP is capable of integrating with biological knowledge-based databases (Uniprot, GO) and high-throughput biology platforms (proteomic, genetic, etc) for system-wise drug target validation. To demonstrate the utility of the CSNAP approach, we combined CSNAP's target prediction with experimental ligand evaluation to identify the major mitotic targets of hit compounds from a cell-based chemical screen and we highlight novel compounds targeting microtubules, an important cancer therapeutic target. The CSNAP method is freely available and can be accessed from the CSNAP web server (http://services.mbi.ucla.edu/CSNAP/). PMID:25826798

Lo, Yu-Chen; Senese, Silvia; Li, Chien-Ming; Hu, Qiyang; Huang, Yong; Damoiseaux, Robert; Torres, Jorge Z

2015-03-01

3

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...

4

Profiling of the Tox21 Chemical Collection for Mitochondrial Function to Identify Compounds that Acutely Decrease Mitochondrial Membrane Potential  

PubMed Central

Background: Mitochondrial dysfunction has been implicated in the pathogenesis of a variety of disorders including cancer, diabetes, and neurodegenerative and cardiovascular diseases. Understanding whether different environmental chemicals and druglike molecules impact mitochondrial function represents an initial step in predicting exposure-related toxicity and defining a possible role for such compounds in the onset of various diseases. Objectives: We sought to identify individual chemicals and general structural features associated with changes in mitochondrial membrane potential (MMP). Methods: We used a multiplexed [two end points in one screen; MMP and adenosine triphosphate (ATP) content] quantitative high throughput screening (qHTS) approach combined with informatics tools to screen the Tox21 library of 10,000 compounds (~ 8,300 unique chemicals) at 15 concentrations each in triplicate to identify chemicals and structural features that are associated with changes in MMP in HepG2 cells. Results: Approximately 11% of the compounds (913 unique compounds) decreased MMP after 1 hr of treatment without affecting cell viability (ATP content). In addition, 309 compounds decreased MMP over a concentration range that also produced measurable cytotoxicity [half maximal inhibitory concentration (IC50) in MMP assay/IC50 in viability assay ? 3; p < 0.05]. More than 11% of the structural clusters that constitute the Tox21 library (76 of 651 clusters) were significantly enriched for compounds that decreased the MMP. Conclusions: Our multiplexed qHTS approach allowed us to generate a robust and reliable data set to evaluate the ability of thousands of drugs and environmental compounds to decrease MMP. The use of structure-based clustering analysis allowed us to identify molecular features that are likely responsible for the observed activity. Citation: Attene-Ramos MS, Huang R, Michael S, Witt KL, Richard A, Tice RR, Simeonov A, Austin CP, Xia M. 2015. Profiling of the Tox21 chemical collection for mitochondrial function to identify compounds that acutely decrease mitochondrial membrane potential. Environ Health Perspect 123:49–56;?http://dx.doi.org/10.1289/ehp.1408642 PMID:25302578

Attene-Ramos, Matias S.; Huang, Ruili; Michael, Sam; Witt, Kristine L.; Richard, Ann; Tice, Raymond R.; Simeonov, Anton; Austin, Christopher P.

2014-01-01

5

Sulfonamides identified as plant immune-priming compounds in high-throughput chemical screening increase disease resistance in Arabidopsis thaliana  

PubMed Central

Plant activators are agrochemicals that protect crops from diseases by activating the plant immune system. To isolate lead compounds for use as practical plant activators, we screened two different chemical libraries composed of various bioactive substances by using an established screening procedure that can selectively identify immune-priming compounds. We identified and characterized a group of sulfonamide compounds – sulfameter, sulfamethoxypyridazine, sulfabenzamide, and sulfachloropyridazine – among the various isolated candidate molecules. These sulfonamide compounds enhanced the avirulent Pseudomonas-induced cell death of Arabidopsis suspension cell cultures and increased disease resistance in Arabidopsis plants against both avirulent and virulent strains of the bacterium. These compounds did not prevent the growth of pathogenic bacteria in minimal liquid media at 200 ?M. They also did not induce the expression of defense-related genes in Arabidopsis seedlings, at least not at 24 and 48 h after treatment, suggesting that they do not act as salicylic acid analogs. In addition, although sulfonamides are known to be folate biosynthesis inhibitors, the application of folate did not restore the potentiation effects of the sulfonamides on pathogen-induced cell death. Our data suggest that sulfonamides potentiate Arabidopsis disease resistance by their novel chemical properties. PMID:23118736

Noutoshi, Yoshiteru; Ikeda, Mika; Saito, Tamio; Osada, Hiroyuki; Shirasu, Ken

2012-01-01

6

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

PubMed

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

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

2015-04-15

7

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

8

Novel Plant Immune-Priming Compounds Identified via High-Throughput Chemical Screening Target Salicylic Acid Glucosyltransferases in Arabidopsis[W][OA  

PubMed Central

Plant activators are compounds, such as analogs of the defense hormone salicylic acid (SA), that protect plants from pathogens by activating the plant immune system. Although some plant activators have been widely used in agriculture, the molecular mechanisms of immune induction are largely unknown. Using a newly established high-throughput screening procedure that screens for compounds that specifically potentiate pathogen-activated cell death in Arabidopsis thaliana cultured suspension cells, we identified five compounds that prime the immune response. These compounds enhanced disease resistance against pathogenic Pseudomonas bacteria in Arabidopsis plants. Pretreatments increased the accumulation of endogenous SA, but reduced its metabolite, SA-O-?-d-glucoside. Inducing compounds inhibited two SA glucosyltransferases (SAGTs) in vitro. Double knockout plants that lack both SAGTs consistently exhibited enhanced disease resistance. Our results demonstrate that manipulation of the active free SA pool via SA-inactivating enzymes can be a useful strategy for fortifying plant disease resistance and may identify useful crop protectants. PMID:22960909

Noutoshi, Yoshiteru; Okazaki, Masateru; Kida, Tatsuya; Nishina, Yuta; Morishita, Yoshihiko; Ogawa, Takumi; Suzuki, Hideyuki; Shibata, Daisuke; Jikumaru, Yusuke; Hanada, Atsushi; Kamiya, Yuji

2012-01-01

9

Chemistry & Biology Synthetic Lethal Screening Identifies Compounds  

E-print Network

-Dependent, Nonapoptotic Cell Death in Oncogenic-RAS-Harboring Cancer Cells Wan Seok Yang1 and Brent R. Stockwell1,2,* 1, such as a nonapoptotic, MEK-de- pendent, and iron-dependent oxidative cell death. Erastin, a previously reported compound VDACs to activate the observed pathway. RSL3 acti- vated a similar death mechanism but in a VDAC

Stockwell, Brent R.

10

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

EPA Science Inventory

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

11

Complex Compound Chemical Heat Pumps  

E-print Network

to adsorbate. Barium chloride, for instance, can complex up to 8 moles of ammonia in Complex compound solid-vapor fluid pairs can one coordination step. be used in heat of reaction heat pumps for temperature amplifier (TA) as well as heat BaC1 2 ? n NH 3... ~ BaCl 2 + n NH 3 amplifier (HA) cycle configurations. (1) This report describes the conceptual hardware with 0 ~ n ~ 8 design for complex compound industrial heat pumps. The main emphasis was directed towards a SOLID-VAroR HEAT OF REACTIOO...

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

12

Quantum chemical studies of estrogenic compounds  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

13

IDENTIFYING CHEMICAL COMPOUNDS IN THE ENVIRONMENT  

EPA Science Inventory

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

14

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...

15

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

16

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

17

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

18

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

19

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

20

CHEMICAL COMPOUND CLASSIFICATION WITH AUTOMATICALLY MINED STRUCTURE PATTERNS.  

PubMed

In this paper we propose new methods of chemical structure classification based on the integration of graph database mining from data mining and graph kernel functions from machine learning. In our method, we first identify a set of general graph patterns in chemical structure data. These patterns are then used to augment a graph kernel function that calculates the pairwise similarity between molecules. The obtained similarity matrix is used as input to classify chemical compounds via a kernel machines such as the support vector machine (SVM). Our results indicate that the use of a pattern-based approach to graph similarity yields performance profiles comparable to, and sometimes exceeding that of the existing state-of-the-art approaches. In addition, the identification of highly discriminative patterns for activity classification provides evidence that our methods can make generalizations about a compound's function given its chemical structure. While we evaluated our methods on molecular structures, these methods are designed to operate on general graph data and hence could easily be applied to other domains in bioinformatics. PMID:20448828

Smalter, A M; Huan, J; Lushington, G H

2008-01-01

21

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

PubMed

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

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

2008-10-19

22

LOSS OF ORGANIC CHEMICALS IN SOIL: PURE COMPOUND TREATABILITY STUDIES  

EPA Science Inventory

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

23

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

24

Quantitative high-throughput screening: A titration-based approach that efficiently identifies biological activities in large chemical libraries  

Microsoft Academic Search

High-throughput screening (HTS) of chemical compounds to identify modulators of molecular targets is a mainstay of pharmaceutical development. Increasingly, HTS is being used to identify chemical probes of gene, pathway, and cell functions, with the ultimate goal of comprehensively delineating relationships between chemical structures and biological activities. Achieving this goal will require methodologies that efficiently generate pharmacological data from the

James Inglese; Douglas S. Auld; Ajit Jadhav; Ronald L. Johnson; Anton Simeonov; Adam Yasgar; Wei Zheng; Christopher P. Austin

2006-01-01

25

LIGAND: database of chemical compounds and reactions in biological pathways  

Microsoft Academic Search

LIGAND is a composite database comprising three sections: COMPOUND for the information about metabolites and other chemical compounds, REACTION for the collection of substrate-product relations representing metabolic and other reactions, and ENZYME for the information about enzyme molecules. The current release (as of September 7, 2001) includes 7298 compounds, 5166 reactions and 3829 enzymes. In addition to the keyword search

Susumu Goto; Yasushi Okuno; Masahiro Hattori; Takaaki Nishioka; Minoru Kanehisa

2002-01-01

26

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...

27

APPLICATION OF AN ANALYSIS PROTOCOL TO IDENTIFY ORGANIC COMPOUNDS NOT IDENTIFIED BY SPECTRUM MATCHING. PART 2: APPENDICES  

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...

28

Using Chemical Change to Identify an Unknown  

NSDL National Science Digital Library

In this activity, learners will develop a method to test five similar-looking powders (baking soda, baking powder, cream of tartar, detergent, and cornstarch) with four test liquids (water, vinegar, iodine solution, red cabbage solution). They will use the characteristic set of reactions for each powder to identify an unknown powder, which is one of the five powders they have tested.

James H. Kessler

2007-01-01

29

A Chemical Stain for Identifying Arsenic-Treated Wood  

E-print Network

A Chemical Stain for Identifying Arsenic-Treated Wood (FINAL) Submitted June 23, 2006 Amy Omae.2 Motivation 4 I.3 Objectives 5 CHAPTER II, DEVELOPMENT OF A CHEMICAL STAIN FOR IDENTIFYING ARSENIC-TREATED WOOD II.1 Applying Phosphate Stains to Arsenate Stains 7 II.2 A Potential Arsenic-Test Kit 14 II.3

Florida, University of

30

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

31

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

32

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

33

Synchrotron radiation identified human chemical fingerprints a novel forensic approach  

E-print Network

Synchrotron 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 a forensic analysis of the fingerprint chemistry, or to identify the latent prints of pre-pubescent children

34

Chemical and Radiological Toxicity of Uranium and Its Compounds  

SciTech Connect

The concentration of uranyl nitrate required to deliver the radiation dose limit for soluble uranium compounds is larger than the toxicity-based concentration limits. Therefore, for soluble uranium compounds, health consequences of exposure are primarily due to their chemical toxicity. For insoluble compounds of uranium, health consequences (e.g., fibrosis and/or carcinogenesis of the lung) are primarily due to irradiation of pulmonary tissues from inhaled respirable particles.

Tansky, R.R.

2001-07-26

35

Compounds with species and cell type specific toxicity identified in a 2000 compound drug screen of neural stem cells and rat mixed cortical neurons.  

PubMed

Human primary neural tissue is a vital component for the quick and simple determination of chemical compound neurotoxicity in vitro. In particular, such tissue would be ideal for high-throughput screens that can be used to identify novel neurotoxic or neurotherapeutic compounds. We have previously established a high-throughput screening platform using human induced pluripotent stem cell (iPSC)-derived neural stem cells (NSCs) and neurons. In this study, we conducted a 2000 compound screen with human NSCs and rat cortical cells to identify compounds that are selectively toxic to each group. Approximately 100 of the tested compounds showed specific toxicity to human NSCs. A secondary screen of a small subset of compounds from the primary screen on human iPSCs, NSC-derived neurons, and fetal astrocytes validated the results from >80% of these compounds with some showing cell specific toxicity. Amongst those compounds were several cardiac glycosides, all of which were selectively toxic to the human cells. As the screen was able to reliably identify neurotoxicants, many with species and cell-type specificity, this study demonstrates the feasibility of this NSC-driven platform for higher-throughput neurotoxicity screens. PMID:25454721

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

2014-12-01

36

IDENTIFYING COMPOUNDS DESPITE CHROMATOGRAPHY LIMITATIONS: ORGANOPHOSPHATES IN TREATED SEWAGE  

EPA Science Inventory

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

37

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

NASA Technical Reports Server (NTRS)

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

Misra, Ajay K.

1993-01-01

38

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.

39

Chemical compounds isolated from Talinum triangulare (Portulacaceae).  

PubMed

This first phytochemical study of Talinum triangulare Leach (Portulacaceae), also known as 'cariru', which is a commonly consumed food in Northern Brazil, allowed the isolation and structural determination of four new compounds: one acrylamide, 3-N-(acryloyl, N-pentadecanoyl) propanoic acid (5), and three new phaeophytins named (15(1)S, 17R, 18R)-Ficuschlorin D acid (3(1),3(2)-didehydro-7-oxo-17(3)-O-phytyl-rhodochlorin-15-acetic acid), (13), Talichorin A (17R, 18R)-phaeophytin b-15(1)-hidroxy, 15(2),15(3)-acetyl-13(1)-carboxilic acid (14), and (15(1)S, 17R, 18R)-phaeophytin b peroxylactone or (15(1)S, 17R, 18R)-hydroperoxy-ficuschlorin D (16), together with twelve known compounds, including four phaeophytins (11,12, 15 and 17). The structures of the compounds were established on the basis of 1D and 2D NMR, IR, HRESI-MS spectra, including GC-MS, and HPLC-UV analysis, as well as comparisons with the literature data. The CD spectra data analysis were used to define the absolute configuration of phaeophytins 12 (13(2)R, 17R, 18R)-13(2)-hydroxyphaeophytin a, 13 and 16, 15 (15(1)S, 17R, 18R)-3(1),3(2)-didehydro-15(1)-hydroxyrhodochlorin-15-acetic acid ?-lactone-15(2)-methyl-17(3)-phytyl ester and 17 (17R, 18R)-purpurin 18-phytyl ester. PMID:24799228

de Oliveira Amorim, Ana Paula; de Carvalho, Almir Ribeiro; Lopes, Norberto Peporine; Castro, Rosane Nora; de Oliveira, Marcia Cristina Campos; de Carvalho, Mário Geraldo

2014-10-01

40

A zebrafish chemical suppressor screening identifies small molecule inhibitors of the Wnt/?-catenin pathway.  

PubMed

Genetic screening for suppressor mutants has been successfully used to identify important signaling regulators. Using an analogy to genetic suppressor screening, we developed a chemical suppressor screening method to identify inhibitors of the Wnt/?-catenin signaling pathway. We used zebrafish embryos in which chemically induced ?-catenin accumulation led to an "eyeless" phenotype and conducted a pilot screening for compounds that restored eye development. This approach allowed us to identify geranylgeranyltransferase inhibitor 286 (GGTI-286), a geranylgeranyltransferase (GGTase) inhibitor. Our follow-up studies showed that GGTI-286 reduces nuclear localization of ?-catenin and transcription dependent on ?-catenin/T cell factor in mammalian cells. In addition to pharmacological inhibition, GGTase gene knockdown also attenuates the nuclear function of ?-catenin. Overall, we validate our chemical suppressor screening as a method for identifying Wnt/?-catenin pathway inhibitors and implicate GGTase as a potential therapeutic target for Wnt-activated cancers. PMID:24684907

Nishiya, Naoyuki; Oku, Yusuke; Kumagai, Yusuke; Sato, Yuki; Yamaguchi, Emi; Sasaki, Akari; Shoji, Momoko; Ohnishi, Yukimi; Okamoto, Hitoshi; Uehara, Yoshimasa

2014-04-24

41

Consistency of systematic chemical identifiers within and between small-molecule databases  

PubMed Central

Background Correctness of structures and associated metadata within public and commercial chemical databases greatly impacts drug discovery research activities such as quantitative structure–property relationships modelling and compound novelty checking. MOL files, SMILES notations, IUPAC names, and InChI strings are ubiquitous file formats and systematic identifiers for chemical structures. While interchangeable for many cheminformatics purposes there have been no studies on the inconsistency of these structure identifiers due to various approaches for data integration, including the use of different software and different rules for structure standardisation. We have investigated the consistency of systematic identifiers of small molecules within and between some of the commonly used chemical resources, with and without structure standardisation. Results The consistency between systematic chemical identifiers and their corresponding MOL representation varies greatly between data sources (37.2%-98.5%). We observed the lowest overall consistency for MOL-IUPAC names. Disregarding stereochemistry increases the consistency (84.8% to 99.9%). A wide variation in consistency also exists between MOL representations of compounds linked via cross-references (25.8% to 93.7%). Removing stereochemistry improved the consistency (47.6% to 95.6%). Conclusions We have shown that considerable inconsistency exists in structural representation and systematic chemical identifiers within and between databases. This can have a great influence especially when merging data and if systematic identifiers are used as a key index for structure integration or cross-querying several databases. Regenerating systematic identifiers starting from their MOL representation and applying well-defined and documented chemistry standardisation rules to all compounds prior to creating them can dramatically increase internal consistency. PMID:23237381

2012-01-01

42

Chemical Genetics Reveals an RGS\\/G-Protein Role in the Action of a Compound  

Microsoft Academic Search

We report here on a chemical genetic screen designed to address the mechanism of action of a small molecule. Small molecules that were active in models of urinary incontinence were tested on the nematode Caenorhabditis elegans, and the resulting phenotypes were used as readouts in a genetic screen to identify possible molecular targets. The mutations giving resistance to compound were

Kevin Fitzgerald; Svetlana Tertyshnikova; Lisa Moore; Lynn Bjerke; Ben Burley; Jian Cao; Pamela Carroll; Robert Choy; Steve Doberstein; Yves Dubaquie; Yvonne Franke; Jenny Kopczynski; Hendrik Korswagen; Stanley R. Krystek; Nicholas J. Lodge; Ronald Plasterk; John Starrett; Terry Stouch; George Thalody; Honey Wayne; Alexander van der Linden; Yongmei Zhang; Stephen G. Walker; Mark Cockett; Judi Wardwell-Swanson; Petra Ross-Macdonald; Rachel M. Kindt

2006-01-01

43

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

44

Chemical procedures to detect carcinogenic compound in domestic wastewater  

NASA Astrophysics Data System (ADS)

This review presents chemical methods to detect carcinogenic compound in wastewater. Atomic absorption spectroscopy (AAS), high performance liquid chromatography (HPLC) and gas chromatography mass spectroscopy (GCMS) and their alternative attached equipments were discussed. The application of each method is elaborated using related studies in the field.

S, Abd Manan T.; A, Malakahmad

2013-06-01

45

CKB - the compound knowledge base: a text based chemical search system.  

PubMed

The Compound Knowledge Base (CKB) was developed as a means of locating structures and additional relevant information from a given known structural identifier. Any of Chemical Abstracts Service Registry Number, company code (code number the producing company refers to the chemical entity internally), generic name (trivial or class name), or trade name (name under which the compound is marketed) can be provided as a query. CKB will provide the remaining available information as well as the corresponding structure for any matching compound in the database. The interface to the Compound Knowledge Base is Internet/World Wide Web-based, using Netscape Navigator and the ChemDraw Pro Plugin, which allows Merck scientists quick and easy access to the database from their desktop. The design and implementation of the database and the search interface are herein detailed. PMID:12444725

Walker, Matthew J; Hull, Richard D; Singh, Suresh B

2002-01-01

46

Chemical occupational risks identified by nurses in a hospital environment.  

PubMed

Hospital nursing workers are exposed to occupational chemical risks. This quantitative study aimed to identify what chemical substances nurses have contact with in their activities, what substances cause health problems and what alterations correspond to possible problems caused by the chemical products they mention. A self-administered data collection instrument was answered by 53 nurses, who mentioned exposure mainly to antibiotics and benzene (100%), iodine (98.1%) and latex-talc (88.7%); the main problem-causing substances mentioned were antineoplastic substances (86.7%), glutaraldehyde (79.2%) and ethylene oxide (75.5%); the described health alterations were: eye watering; allergic reactions; nausea and vomiting, while other health problems that can be caused by the above listed products were not mentioned. These workers need further information on occupational chemical risks, which they could have received in undergraduate or permanent education courses. PMID:16699695

Xelegati, Rosicler; Robazzi, Maria Lúcia do Carmo Cruz; Marziale, Maria Helena Palucci; Haas, Vanderlei José

2006-01-01

47

Cyclopropyl Carboxamides, a Chemically Novel Class of Antimalarial Agents Identified in a Phenotypic Screen ?  

PubMed Central

Malaria is one of the deadliest infectious diseases in the world, with the eukaryotic parasite Plasmodium falciparum causing the most severe form of the disease. Discovery of new classes of antimalarial drugs has become an urgent task to counteract the increasing problem of drug resistance. Screening directly for compounds able to inhibit parasite growth in vitro is one of the main approaches the malaria research community is now pursuing for the identification of novel antimalarial drug leads. Very recently, thousands of compounds with potent activity against the parasite P. falciparum have been identified and information about their molecular descriptors, antiplasmodial potency, and cytotoxicity is publicly available. Now the challenges are how to identify the most promising chemotypes for further development and how best to progress these compounds through a lead optimization program to generate antimalarial drug candidates. We report here the first chemical series to be characterized from one of those screenings, a completely novel chemical class with the generic name cyclopropyl carboxamides that has never before been described as having antimalarial or other pharmacological activities. Cyclopropyl carboxamides are potent inhibitors of drug-sensitive and -resistant strains of P. falciparum in vitro and show in vivo oral efficacy in malaria mouse models. In the present work, we describe the biological characterization of this chemical family, showing that inhibition of their still unknown target has very favorable pharmacological consequences but the compounds themselves seem to select for resistance at a high frequency. PMID:21968362

Sanz, Laura M.; Jiménez-Díaz, M. Belen; Crespo, Benigno; De-Cozar, Cristina; Almela, M. Jesus; Angulo-Barturen, Iñigo; Castañeda, Pablo; Ibañez, Javier; Fernández, Esther Pilar; Ferrer, Santiago; Herreros, Esperanza; Lozano, Sonia; Martínez, María Santos; Rueda, Lourdes; Burrows, Jeremy N.; García-Bustos, Jose F.; Gamo, Francisco-Javier

2011-01-01

48

Loss of organic chemicals in soil: Pure compound treatability studies  

SciTech Connect

Comprehensive screening data on the treatability of 32 organic chemicals in soil were developed. Of the evaluated chemicals, 22 were phenolic compounds. Aerobic batch laboratory microcosm experiments were conducted using two soils: an acidic clay soil with <1 percent organic matter and a slightly basic sandy loam soil containing 3.25 percent organic matter. Loss rates were determined for the 32 chemicals with each soil and were higher in the basic soil. The loss rates were compared with chemical structure. Chlorophenols with chlorine substituted in the meta-position had greater half-lives and lower loss rates. Chemicals with a nitro group substituted in the phenol ring appeared to have a lower loss rate.

Loehr, R.C.; Matthews, J.E.

1992-01-01

49

Identifying non-point sources of endocrine active compounds and their biological impacts in freshwater lakes.  

PubMed

Contaminants of emerging concern, particularly endocrine active compounds (EACs), have been identified as a threat to aquatic wildlife. However, little is known about the impact of EACs on lakes through groundwater from onsite wastewater treatment systems (OWTS). This study aims to identify specific contributions of OWTS to Sullivan Lake, Minnesota, USA. Lake hydrology, water chemistry, caged bluegill sunfish (Lepomis macrochirus), and larval fathead minnow (Pimephales promelas) exposures were used to assess whether EACs entered the lake through OWTS inflow and the resultant biological impact on fish. Study areas included two OWTS-influenced near-shore sites with native bluegill spawning habitats and two in-lake control sites without nearby EAC sources. Caged bluegill sunfish were analyzed for plasma vitellogenin concentrations, organosomatic indices, and histological pathologies. Surface and porewater was collected from each site and analyzed for EACs. Porewater was also collected for laboratory exposure of larval fathead minnow, before analysis of predator escape performance and gene expression profiles. Chemical analysis showed EACs present at low concentrations at each study site, whereas discrete variations were reported between sites and between summer and fall samplings. Body condition index and liver vacuolization of sunfish were found to differ among study sites as did gene expression in exposed larval fathead minnows. Interestingly, biological exposure data and water chemistry did not match. Therefore, although results highlight the potential impacts of seepage from OWTS, further investigation of mixture effects and life history factor as well as chemical fate is warranted. PMID:24974177

Baker, Beth H; Martinovic-Weigelt, Dalma; Ferrey, Mark; Barber, Larry B; Writer, Jeffery H; Rosenberry, Donald O; Kiesling, Richard L; Lundy, James R; Schoenfuss, Heiko L

2014-10-01

50

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

51

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

52

Analysis of chlorocarbon compounds identified in the SAM Investigation of the Mars Science Laboratory mission  

NASA Astrophysics Data System (ADS)

The gas chromatograph mass spectrometer (GCMS) mode of the Sample Analysis at Mars (SAM) experiment was designed for the separation and identification of the chemical components of the gases released from a solid sample or trapped from the atmosphere. Gases from solid samples are either produced by heating a cell from ambient to >800-1100oC (EGA mode) or by wet chemistry extraction and reactions (not yet employed on Mars). Prior to EGA analysis of portions of the first 3 solid samples (Rocknest, John Klein and Cumberland) collected by MSL and delivered to SAM, an internal SAM blank run was carried out with an empty quartz cup. These blank analyses are required to understand the background signal intrinsic to the GCMS and its gas manifolds and traps. Several peaks have been identified as part of SAM background, some of them below the nmol level, which attests of the sensitivity of the instrument and as-designed performance of the GCMS. The origin of each peak has been investigated, and two major contributors are revealed; residual vapor from one of the chemicals used for SAM wet chemistry experiment: N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide (MTBSTFA), and the Tenax from the hydrocarbon trap. Supporting lab experiments are in progress to understand the reaction pathways of the molecules identified in the SAM background. These experiments help elucidate which molecules may be interpreted as indigenous to Mars. Of the three solid samples analyzed on 11 runs, it was possible to detect and identify several chlorinated compounds including several chlorohydrocarbons. The chlorine is likely derived from the decomposition of martian perchlorates or other indigenous Cl-containing species while the origin of the carbon is presently under investigation for each detected molecule. To date, a subset these molecules have been identified in lab studies and a terrestrial contribution to the observed products are more easily explained. The combined results from SAM and the associated laboratory studies represent a significant step forward in the search for near-surface organic compounds on Mars.

Freissinet, Caroline; Mahaffy, P.; Glavin, D.; Buch, A.; Brunner, A.; Eigenbrode, J.; Martin, M.; Miller, K.; Steele, A.; Szopa, C.; SAM; MSL science Team

2013-10-01

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.

Labushev, Mikhail M

2013-01-01

54

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

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

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

57

Integration of chemical and RNAi multiparametric profiles identifies triggers of intracellular mycobacterial killing.  

PubMed

Pharmacological modulators of host-microbial interactions can in principle be identified using high-content screens. However, a severe limitation of this approach is the lack of insights into the mode of action of compounds selected during the primary screen. To overcome this problem, we developed a combined experimental and computational approach. We designed a quantitative multiparametric image-based assay to measure intracellular mycobacteria in primary human macrophages, screened a chemical library containing FDA-approved drugs, and validated three compounds for intracellular killing of M. tuberculosis. By integrating the multiparametric profiles of the chemicals with those of siRNAs from a genome-wide survey on endocytosis, we predicted and experimentally verified that two compounds modulate autophagy, whereas the third accelerates endosomal progression. Our findings demonstrate the value of integrating small molecules and genetic screens for identifying cellular mechanisms modulated by chemicals. Furthermore, selective pharmacological modulation of host trafficking pathways can be applied to intracellular pathogens beyond mycobacteria. PMID:23414754

Sundaramurthy, Varadharajan; Barsacchi, Rico; Samusik, Nikolay; Marsico, Giovanni; Gilleron, Jerome; Kalaidzidis, Inna; Meyenhofer, Felix; Bickle, Marc; Kalaidzidis, Yannis; Zerial, Marino

2013-02-13

58

Chemical Biology Drug Sensitivity Screen Identifies Sunitinib as Synergistic Agent with Disulfiram in Prostate Cancer Cells  

PubMed Central

Background Current treatment options for castration- and treatment-resistant prostate cancer are limited and novel approaches are desperately needed. Our recent results from a systematic chemical biology sensitivity screen covering most known drugs and drug-like molecules indicated that aldehyde dehydrogenase inhibitor disulfiram is one of the most potent cancer-specific inhibitors of prostate cancer cell growth, including TMPRSS2-ERG fusion positive cancers. However, the results revealed that disulfiram alone does not block tumor growth in vivo nor induce apoptosis in vitro, indicating that combinatorial approaches may be required to enhance the anti-neoplastic effects. Methods and Findings In this study, we utilized a chemical biology drug sensitivity screen to explore disulfiram mechanistic details and to identify compounds potentiating the effect of disulfiram in TMPRSS2-ERG fusion positive prostate cancer cells. In total, 3357 compounds including current chemotherapeutic agents as well as drug-like small molecular compounds were screened alone and in combination with disulfiram. Interestingly, the results indicated that androgenic and antioxidative compounds antagonized disulfiram effect whereas inhibitors of receptor tyrosine kinase, proteasome, topoisomerase II, glucosylceramide synthase or cell cycle were among compounds sensitizing prostate cancer cells to disulfiram. The combination of disulfiram and an antiangiogenic agent sunitinib was studied in more detail, since both are already in clinical use in humans. Disulfiram-sunitinib combination induced apoptosis and reduced androgen receptor protein expression more than either of the compounds alone. Moreover, combinatorial exposure reduced metastatic characteristics such as cell migration and 3D cell invasion as well as induced epithelial differentiation shown as elevated E-cadherin expression. Conclusions Taken together, our results propose novel combinatorial approaches to inhibit prostate cancer cell growth. Disulfiram-sunitinib combination was identified as one of the potent synergistic approaches. Since sunitinib alone has been reported to lack efficacy in prostate cancer clinical trials, our results provide a rationale for novel combinatorial approach to target prostate cancer more efficiently. PMID:23251544

Ketola, Kirsi; Kallioniemi, Olli; Iljin, Kristiina

2012-01-01

59

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 Techniques Abhyuday Mandal* Department of Statistics, University of Georgia, Athens, Georgia 30602-1952 Kjell, Michigan 48105 Received December 14, 2006 Throughout the drug discovery process, discovery teams

Wu, Jeff

60

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

61

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

62

Volatile compounds emitted by Triatoma dimidiata, a vector of Chagas disease: chemical analysis and behavioural evaluation.  

PubMed

In this study, we evaluated the responses of Triatoma dimidiata Latreille (Hemiptera: Reduviidae) to volatiles emitted by conspecific females, males, mating pairs and metasternal gland (MG) extracts with a Y-tube olfactometer. The volatile compounds released by mating pairs and MGs of T. dimidiata were identified using solid-phase microextraction and coupled gas chromatography-mass spectrometry (GC-MS). Females were not attracted to volatiles emitted by males or MG extracts; however, they preferred clean air to their own volatiles or those from mating pairs. Males were attracted to volatiles emitted by males, females, mating pairs, pairs in which the male had the MG orifices occluded or MG extracts of both sexes. However, males were not attracted to volatiles emitted by pairs in which the female had the MG orifices occluded. The chemical analyses showed that 14 and 15 compounds were detected in the headspace of mating pairs and MG, respectively. Most of the compounds identified from MG except for isobutyric acid were also detected in the headspace of mating pairs. Both females and males were attracted to octanal and 6-methyl-5-hepten-2-one, and males were attracted to 3,5-dimethyl-2-hexanol. Males but not females were attracted to a seven-compound blend, formulated from compounds identified in attractive MG extracts. PMID:23205718

May-Concha, I; Rojas, J C; Cruz-López, L; Millar, J G; Ramsey, J M

2013-06-01

63

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

64

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

65

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

66

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

67

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

PubMed Central

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

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

2015-01-01

68

Chemical screen identifies FDA-approved drugs and target pathways that induce precocious pancreatic endocrine differentiation  

PubMed Central

Pancreatic ?-cells are an essential source of insulin and their destruction because of autoimmunity causes type I diabetes. We conducted a chemical screen to identify compounds that would induce the differentiation of insulin-producing ?-cells in vivo. To do this screen, we brought together the use of transgenic zebrafish as a model of ?-cell differentiation, a unique multiwell plate that allows easy visualization of lateral views of swimming larval fish and a library of clinical drugs. We identified six hits that can induce precocious differentiation of secondary islets in larval zebrafish. Three of these six hits were known drugs with a considerable background of published data on mechanism of action. Using pharmacological approaches, we have identified and characterized two unique pathways in ?-cell differentiation in the zebrafish, including down-regulation of GTP production and retinoic acid biosynthesis. PMID:22084084

Rovira, Meritxell; Huang, Wei; Yusuff, Shamila; Shim, Joong Sup; Ferrante, Anthony A.; Liu, Jun O.; Parsons, Michael J.

2011-01-01

69

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

70

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

PubMed

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

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

2015-03-01

71

A Screen for Kinetochore-Microtubule Interaction Inhibitors Identifies Novel Antitubulin Compounds  

PubMed Central

Background Protein assemblies named kinetochores bind sister chromatids to the mitotic spindle and orchestrate sister chromatid segregation. Interference with kinetochore activity triggers a spindle checkpoint mediated arrest in mitosis, which frequently ends in cell death. We set out to identify small compounds that inhibit kinetochore-microtubule binding for use in kinetochore-spindle interaction studies and to develop them into novel anticancer drugs. Methodology/Principal Findings A fluorescence microscopy-based in vitro assay was developed to screen compound libraries for molecules that prevented the binding of a recombinant human Ndc80 kinetochore complex to taxol-stabilized microtubules. An active compound was identified that acted at the microtubule level. More specifically, by localizing to the colchicine-binding site in ??-tubulin the hit compound prevented the Ndc80 complex from binding to the microtubule surface. Next, structure-activity analyses distinguished active regions in the compound and led to the identification of highly potent analogs that killed cancer cells with an efficacy equaling that of established spindle drugs. Conclusions/Significance The compound identified in our screen and its subsequently identified analogs represent new antitubulin chemotypes that can be synthetically developed into a novel class of antimitotic spindle drugs. In addition, they are stereochemically unique as their R- and S-isomers mimic binding of colchicine and podophyllotoxin, respectively, two antitubulin drugs that interact differently with the tubulin interface. Model-driven manipulation of our compounds promises to advance insight into how antitubulin drugs act upon tubulin. These advances in turn may lead to tailor-made colchicine site agents which would be valuable new assets to fight a variety of tumors, including those that have become resistant to the (antispindle) drugs used today. PMID:20657644

Nguyen, Tam; Silvestri, Romano; Gussio, Rick; Musacchio, Andrea; Hamel, Ernest; De Wulf, Peter

2010-01-01

72

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

PubMed Central

Injury to the central nervous system (CNS) can result in lifelong loss of function due in part to the regenerative failure of CNS neurons. Inhibitory proteins derived from myelin and the astroglial scar are major barriers for the successful regeneration of injured CNS neurons. Previously, we described the identification of a novel compound, F05, which promotes neurite growth from neurons challenged with inhibitory substrates in vitro, and promotes axonal regeneration in vivo (Usher et al., 2010). To identify additional regeneration-promoting compounds, we used F05-induced gene expression profiles to query the Broad Institute Connectivity Map, a gene expression database of cells treated with >1,300 compounds. Despite no shared chemical similarity, F05-induced changes in gene expression were remarkably similar to those seen with a group of piperazine phenothiazine antipsychotics (PhAPs). In contrast to antipsychotics of other structural classes, PhAPs promoted neurite growth of CNS neurons challenged with two different glial derived inhibitory substrates. Our pharmacological studies suggest a mechanism whereby PhAPs promote growth through antagonism of calmodulin signaling, independent of dopamine receptor antagonism. These findings shed light on mechanisms underlying neurite-inhibitory signaling, and suggest that clinically approved antipsychotic compounds may be repurposed for use in CNS injured patients. PMID:22561309

Johnstone, AL; Reierson, GW; Smith, RP; Goldberg, JL; Lemmon, VP; Bixby, JL

2012-01-01

73

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

PubMed

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

2012-10-01

74

[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

75

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

76

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

PubMed

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 small hairpin RNA (shRNA) screens to identify a distinctive class of inhibitors that target nicotinamide phosphoribosyl transferase (NAMPT), a rate-limiting enzyme in the biosynthesis of nicotinamide adenine dinucleotide, 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

2013-11-21

77

Increasing analytical capacity in the search to identify compounds that kill young wheat stem sawfly larvae  

E-print Network

Increasing analytical capacity in the search to identify compounds that kill young wheat stem insect pest species in wheat. Two examples that have some relevance to Montana are antibiosis to Hessian fly (HF) and to orange wheat blossom midge (OWBM), both occasional pests of wheat. In the case of both

Maxwell, Bruce D.

78

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...

79

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...

80

Sensitivity of animals to chemical compounds links to metabolic rate.  

PubMed

Ecotoxicological studies have shown considerable variation in species sensitivity for chemical compounds, but general patterns in sensitivity are still not known. A better understanding of this sensitivity is important in the context of environmental risk assessment but also in a more general ecological and evolutionary one. We investigated the metabolic rate or more precise the specific somatic maintenance (expressed in J cm(-3) d(-1), at a standardised body temperature of 20 °C) on the sensitivity of a species to chemical poisoning. The sensitivity of a species was expressed in terms of its threshold concentration for survival, the no effect concentrations (NEC, in µmol/L). Somatic maintenance data were based on the 'add-my-pet' database hosted by the VU University of Amsterdam. NECs were derived from the US-EPA ECOTOX database. We focussed on four pesticides; two that need a metabolic activation, Chlorpyrifos and Malathion, and two without metabolic activation, carbofuran and carbaryl. All four pesticides showed a similar response: a strong negative correlation between the specific somatic maintenance and the NEC. We discuss possible explanations, deviations and ecological implications. PMID:25564013

Baas, Jan; Kooijman, Sebastiaan A L M

2015-04-01

81

Method for halogenating or radiohalogenating a chemical compound  

DOEpatents

A method for obtaining a halogenated organic compound, whereby an organotrifluoroborate compound is reacted with a halide ion in the presence of an oxidizing agent to produce the corresponding halogenated organic compound. The method may be used for producing radiohalogenated organic compounds.

Kabalka, George W.

2006-05-09

82

Docking of a novel DNA methyltransferase inhibitor identified from high-throughput screening: insights to unveil inhibitors in chemical databases.  

PubMed

Inhibitors of DNA methyltransferase (DNMT) are attractive compounds not only as potential therapeutic agents for the treatment of cancer and other diseases, but also as research tools to investigate the role of DNMTs in epigenetic events. Recent advances in high-throughput screening (HTS) for epigenetic targets and the availability of the first crystallographic structure of human DNMT1 encourage the integration of research strategies to uncover and optimize the activity of DNMT inhibitors. Herein, we present a binding model of a novel small-molecule DNMT1 inhibitor obtained by HTS, recently released in a public database. The docking model is in agreement with key interactions previously identified for established inhibitors using extensive computational studies including molecular dynamics and structure-based pharmacophore modeling. Based on the chemical structure of the novel inhibitor, a sequential computational screening of five chemical databases was performed to identify candidate compounds for testing. Similarity searching followed by molecular docking of chemical databases such as approved drugs, natural products, a DNMT-focused library, and a general screening collection, identified at least 108 molecules with promising DNMT inhibitory activity. The chemical structures of all hit compounds are disclosed to encourage the research community working on epigenetics to test experimentally the enzymatic and demethylating activity in vivo. Five candidate hits are drugs approved for other indications and represent potential starting points of a drug repurposing strategy. PMID:23447100

Medina-Franco, José L; Yoo, Jakyung

2013-05-01

83

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

84

Bioautography and chemical characterization of antimicrobial compound(s) in commercial water-soluble annatto extracts.  

PubMed

Annatto preparations based on extracts of the seed of tropical bush Bixa orellana L consist of carotenoid-type pigments. Previous reports indicate that commercial annatto extracts have biological activities against microorganisms of significance to food fermentation, preservation, and safety. The objective of this study was to separate and identify the compound(s) responsible for the antimicrobial activity of annatto preparations. Commercial water-soluble annatto extracts were screened by thin-layer chromatography and bioautography followed by liquid chromatography/photodiode array/mass spectrometry (LC/PDA/MS) analysis of active fractions. Bioautography revealed two fractions with antimicrobial activity against Staphylococcus aureus. LC/PDA/MS analysis of both fractions revealed 9'-cis-norbixin (UV(max) 460 and 489 nm) and all-trans-norbixin (UV(max) 287, 470, and 494 nm) as the major components. Structure confirmation was achieved by (1)H NMR spectroscopy. Results indicate that 9'-cis-norbixin and all-trans-norbixin are responsible for the antimicrobial properties of annatto. PMID:15796589

Galindo-Cuspinera, Veronica; Rankin, Scott A

2005-04-01

85

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

86

Inferring Genetic Networks and Identifying Compound Mode of Action via Expression Profiling  

NASA Astrophysics Data System (ADS)

The complexity of cellular gene, protein, and metabolite networks can hinder attempts to elucidate their structure and function. To address this problem, we used systematic transcriptional perturbations to construct a first-order model of regulatory interactions in a nine-gene subnetwork of the SOS pathway in Escherichia coli. The model correctly identified the major regulatory genes and the transcriptional targets of mitomycin C activity in the subnetwork. This approach, which is experimentally and computationally scalable, provides a framework for elucidating the functional properties of genetic networks and identifying molecular targets of pharmacological compounds.

Gardner, Timothy S.; di Bernardo, Diego; Lorenz, David; Collins, James J.

2003-07-01

87

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

88

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

89

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

PubMed

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. 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 green fluorescent protein (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, we tested compounds by Western blot analysis and in a Caenorhabditis elegans 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

Boyd, Justin D; Lee-Armandt, J Peter; Feiler, Marisa S; Zaarur, Nava; Liu, Min; Kraemer, Brian; Concannon, John B; Ebata, Atsushi; Wolozin, Benjamin; Glicksman, Marcie A

2014-01-01

90

Gas chromatograph-mass spectrometer (GC/MS) system for quantitative analysis of reactive chemical compounds  

DOEpatents

Described is a new gas chromatograph-mass spectrometer (GC/MS) system and method for quantitative analysis of reactive chemical compounds. All components of such a GC/MS system external to the oven of the gas chromatograph are programmably temperature controlled to operate at a volatilization temperature specific to the compound(s) sought to be separated and measured.

Grindstaff, Quirinus G. (Oak Ridge, TN)

1992-01-01

91

THE ELECTRONIC STRUCTURE AND PHYSICAL PROPERTIES OF THIONITROSO COMPOUNDS—A QUANTUM CHEMICAL STUDY  

Microsoft Academic Search

Semiempirical and nonempirical quantum chemical methods have been used to describe the electronic structure and physical properties of thionitroso compounds unknown so far. Predictions on geometry, electron distribution, ionization potential, electron affinity, UV-VIS spectrum and the S0?T1?energy splitting of these compounds have been made. First experimental results on thionitroso compounds are critically examined.

A. Mehlhorn; J. Sauer; J. Fabian; R. Mayer

1981-01-01

92

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

PubMed

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

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

2015-01-01

93

Chemical Genomic Profiling via Barcode Sequencing to Predict Compound Mode of Action.  

PubMed

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

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

2015-01-01

94

Genomic Models of Short-Term Exposure Accurately Predict Long-Term Chemical Carcinogenicity and Identify Putative Mechanisms of Action  

PubMed Central

Background Despite an overall decrease in incidence of and mortality from cancer, about 40% of Americans will be diagnosed with the disease in their lifetime, and around 20% will die of it. Current approaches to test carcinogenic chemicals adopt the 2-year rodent bioassay, which is costly and time-consuming. As a result, fewer than 2% of the chemicals on the market have actually been tested. However, evidence accumulated to date suggests that gene expression profiles from model organisms exposed to chemical compounds reflect underlying mechanisms of action, and that these toxicogenomic models could be used in the prediction of chemical carcinogenicity. Results In this study, we used a rat-based microarray dataset from the NTP DrugMatrix Database to test the ability of toxicogenomics to model carcinogenicity. We analyzed 1,221 gene-expression profiles obtained from rats treated with 127 well-characterized compounds, including genotoxic and non-genotoxic carcinogens. We built a classifier that predicts a chemical's carcinogenic potential with an AUC of 0.78, and validated it on an independent dataset from the Japanese Toxicogenomics Project consisting of 2,065 profiles from 72 compounds. Finally, we identified differentially expressed genes associated with chemical carcinogenesis, and developed novel data-driven approaches for the molecular characterization of the response to chemical stressors. Conclusion Here, we validate a toxicogenomic approach to predict carcinogenicity and provide strong evidence that, with a larger set of compounds, we should be able to improve the sensitivity and specificity of the predictions. We found that the prediction of carcinogenicity is tissue-dependent and that the results also confirm and expand upon previous studies implicating DNA damage, the peroxisome proliferator-activated receptor, the aryl hydrocarbon receptor, and regenerative pathology in the response to carcinogen exposure. PMID:25058030

Gusenleitner, Daniel; Auerbach, Scott S.; Melia, Tisha; Gómez, Harold F.; Sherr, David H.; Monti, Stefano

2014-01-01

95

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

96

Pilot-scale compound screening against RNA editing identifies trypanocidal agents.  

PubMed

Most mitochondrial messenger RNAs in trypanosomatid pathogens undergo a unique type of posttranscriptional modification involving insertion and/or deletion of uridylates. This process, RNA editing, is catalyzed by a multiprotein complex (~1.6 MDa), the editosome. Knockdown of core editosome proteins compromises mitochondrial function and, ultimately, parasite viability. Hence, because the editosome is restricted to trypanosomatids, it serves as a unique drug target in these pathogens. Currently, there is a lack of editosome inhibitors for antitrypanosomatid drug development or that could serve as unique tools for perturbing and characterizing editosome interactions or RNA editing reaction stages. Here, we screened a library of pharmacologically active compounds (LOPAC1280) using high-throughput screening to identify RNA editing inhibitors. We report that aurintricarboxylic acid, mitoxantrone, PPNDS, and NF449 are potent inhibitors of deletion RNA editing (IC50 range, 1-5 µM). However, none of these compounds could specifically inhibit the catalytic steps of RNA editing. Mitoxantrone blocked editing by inducing RNA-protein aggregates, whereas the other three compounds interfered with editosome-RNA interactions to varying extents. Furthermore, NF449, a suramin analogue, was effective at killing Trypanosoma brucei in vitro. Thus, new tools for editosome characterization and downstream RNA editing inhibitor have been identified. PMID:25170016

Moshiri, Houtan; Mehta, Vaibhav; Yip, Chun Wai; Salavati, Reza

2015-01-01

97

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

98

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

99

Organic--Inorganic Layer Compounds: Physical Properties and Chemical Reactions  

Microsoft Academic Search

In contrast with intercalation compounds, which can exist both with and without organic molecules between the planes of inorganic material, `molecular composite' compounds have organic groups covalently or ionically bound to inorganic layers. In such crystals the aim is to combine magnetic or optical properties characteristic of the inorganic solid state, like magnetism and luminescence, with properties found in the

P. Day

1985-01-01

100

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

101

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

102

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

DOEpatents

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

Michaels, E.D.

1981-02-25

103

GPM: A graph pattern matching kernel with diffusion for chemical compound classification  

Microsoft Academic Search

Classifying chemical compounds is an active topic in drug design and other cheminformatics applications. Graphs are general tools for organizing information from heterogenous sources and have been applied in modelling many kinds of biological data. With the fast accumulation of chemical structure data, building highly accurate predictive models for chemical graphs emerges as a new challenge . In this paper,

Aaron M. Smalter; Jun Huan; Gerald H. Lushington

2008-01-01

104

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 substructures. Search engines have been developed to use this data tree to enable query on inhibitors of HIV protease (http://xpdb.nist. gov/hivsdb/hivsdb.html). These search engines use a new novel technique

105

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

106

Analogue Experiments Identify Possible Precursor Compounds for Chlorohydrocarbons Detected in SAM  

NASA Astrophysics Data System (ADS)

Since landing at Gale Crater on August 6, 2012, the Sample Analysis at Mars (SAM) instrument suite, aboard the Curiosity Rover, has conducted multiple analyses of scooped and drilled samples and has identified a suite of chlorohydrocarbons including chloromethane, dichloromethane, trichloromethane, chloromethylpropene, and chlorobenzene (Glavin et al., 2013; Leshin et al., 2013). These compounds were identified after samples were pyrolysed at temperatures up to ~835°C through a combination of Evolved Gas Analysis (EGA) and Gas Chromatography Mass Spectrometry (GCMS). Since these chlorinated species were well above the background levels determined by empty cup blanks analyzed prior to solid sample analyses, thermal degradation of oxychlorine phases, such as perchlorate, present in the Martian soil, are the most likely source of chlorine needed to generate these chlorohydrocarbons. Laboratory analogue experiments show that terrestrial organics internal to SAM, such as N-methyl-N(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA), a derivatization agent, can react with perchlorates to produce all of the chlorohydrocarbons detected by SAM. However, in pyrolysis-trap-GCMS laboratory experiments with MTBSTFA, C4 compounds are the predominant chlorohydrocarbon observed, whereas on SAM the C1 chlorohydrocarbons dominate (Glavin et al., 2013). This, in addition to the previous identification of chloromethane and dichloromethane by the 1976 Viking missions (Biemann et al., 1977), suggest that there could be another, possibly Martian, source of organic carbon contributing to the formation of the C1 chlorohydrocarbons, or other components of the solid samples analyzed by SAM are having a catalytic effect on chlorohydrocarbon generation. Laboratory analogue experiments investigated a suite of organic compounds that have the potential to accumulate on Mars (Benner et al., 2000) and thus serve as sources of carbon for the formation of chlorohydrocarbons detected by the SAM and Viking GCMS instruments. Experiments were conducted under SAM-like conditions using a commercial pyroprobe equipped with a SAM-like hydrocarbon trap and coupled to a GCMS. In general, when pyrolyzed with 1 wt.% calcium perchlorate, the C1 organic compounds (e.g. methanol, formic acid, and formaldehyde) produced only C1 chlorinated compounds while propanol and butyric acid formed only C3 chlorinated compounds. All of the pyrolysis experiments produced chlorobenzene, suggesting that it forms from chlorine, released during calcium perchlorate decomposition, reacting with benzene and toluene, released from the Tenax component of the hydrocarbon trap. Pyrolysis of phthalic acid however, produces a higher abundance of chlorobenzene than could be attributed to the Tenax alone and also forms C1 chlorohydrocarbons. Additional analogue experiments to identify potential precursor compounds for the chlorohydrocarbons detected by SAM are ongoing. Benner et al., 2000, PNAS, 97(6), 2425-2430 Biemann et al., 1977, JGR, 82(28), 4641-4658 Glavin et al., 2013, JGR-Planets, accepted for publication Leshin et al., 2013, Science, in press

Miller, K.; Summons, R. E.; Eigenbrode, J. L.; Freissinet, C.; Glavin, D. P.; Martin, M. G.; Team, M.

2013-12-01

107

Chemical profiles and identification of key compound caffeine in marine-derived traditional Chinese medicine Ostreae concha.  

PubMed

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 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

2012-05-01

108

[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

109

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

110

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

111

Whole-exome sequencing identifies compound heterozygous mutations in WDR62 in siblings with recurrent polymicrogyria.  

PubMed

Polymicrogyria is a disorder of neuronal development resulting in structurally abnormal cerebral hemispheres characterized by over-folding and abnormal lamination of the cerebral cortex. Polymicrogyria is frequently associated with severe neurologic deficits including intellectual disability, motor problems, and epilepsy. There are acquired and genetic causes of polymicrogyria, but most patients with a presumed genetic etiology lack a specific diagnosis. Here we report using whole-exome sequencing to identify compound heterozygous mutations in the WD repeat domain 62 (WDR62) gene as the cause of recurrent polymicrogyria in a sibling pair. Sanger sequencing confirmed that the siblings both inherited 1-bp (maternal allele) and 2-bp (paternal allele) frameshift deletions, which predict premature truncation of WDR62, a protein that has a role in early cortical development. The probands are from a non-consanguineous family of Northern European descent, suggesting that autosomal recessive PMG due to compound heterozygous mutation of WDR62 might be a relatively common cause of PMG in the population. Further studies to identify mutation frequency in the population are needed. PMID:21834044

Murdock, David R; Clark, Gary D; Bainbridge, Matthew N; Newsham, Irene; Wu, Yuan-Qing; Muzny, Donna M; Cheung, Sau Wai; Gibbs, Richard A; Ramocki, Melissa B

2011-09-01

112

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

113

Identifying indicators of reactivity for chemical reductants in sediments.  

PubMed

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. For this purpose the reactivity, as defined by pseudofirst order reduction rate constants for p-cyanonitrobenzene (pCNB), was measured in twenty-one natural sediments of different origins that were incubated to attain both anoxic (less reducing) and anaerobic (microbially reducing) conditions. The reactivity of the anoxic sediments increased with pH and an increasing amount of Fe(II) added. A good electron balance between pCNB reduction and Fe(II) consumption was observed for anaerobic sediments of high solids loading (50 g/L), but not when solids loading was 5 g/L. Based on cluster and regression analysis, pCNB reactivity in the anaerobic sediments correlates strongly with aqueous Fe(II) concentrations for sediments with low organic carbon (OC) content (<4.2%), but with dissolved OC concentrations (DOC) for the sediments with high OC content (>6.4%). These observations indicate surface-associated Fe(II) and reduced DOC are the predominant reductants in the anaerobic sediments, and that aqueous Fe(II) and DOC will serve as readily measurable indicators of pCNB reactivity in these systems. PMID:23088410

Zhang, Huichun; Weber, Eric J

2013-07-01

114

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...

115

Chemical properties and methods of analysis of refractory compounds  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

116

Whole-Animal Chemical Screen Identifies Colistin as a New Immunomodulator That Targets Conserved Pathways  

PubMed Central

ABSTRACT The purpose of this study was to take advantage of the nematode Caenorhabditis elegans to perform a whole-animal chemical screen to identify potential immune activators that may confer protection against bacterial infections. We identified 45 marketed drugs, out of 1,120 studied compounds, that are capable of activating a conserved p38/PMK-1 mitogen-activated protein kinase pathway required for innate immunity. One of these drugs, the last-resort antibiotic colistin, protected against infections by the Gram-negative pathogens Yersinia pestis and Pseudomonas aeruginosa but not by the Gram-positive pathogens Enterococcus faecalis and Staphylococcus aureus. Protection was independent of the antibacterial activity of colistin, since the drug was administered prophylactically prior to the infections and it was also effective against antibiotic-resistant bacteria. Immune activation by colistin is mediated not only by the p38/PMK-1 pathway but also by the conserved FOXO transcription factor DAF-16 and the transcription factor SKN-1. Furthermore, p38/PMK-1 was found to be required in the intestine for immune activation by colistin. Enhanced p38/PMK-1-mediated immune responses by colistin did not reduce the bacterial burden, indicating that the pathway plays a role in the development of host tolerance to infections by Gram-negative bacteria. PMID:25118236

Cai, Yun; Cao, Xiou

2014-01-01

117

Potent Plasmodium falciparum Gametocytocidal Activity of Diaminonaphthoquinones, Lead Antimalarial Chemotypes Identified in an Antimalarial Compound Screen.  

PubMed

Forty percent of the world's population is threatened by malaria, which is caused by Plasmodium parasites and results in an estimated 200 million clinical cases and 650,000 deaths each year. Drug resistance has been reported for all commonly used antimalarials and has prompted screens to identify new drug candidates. However, many of these new candidates have not been evaluated against the parasite stage responsible for transmission, gametocytes. If Plasmodium falciparum gametocytes are not eliminated, patients continue to spread malaria for weeks after asexual parasite clearance. Asymptomatic individuals can also harbor gametocyte burdens sufficient for transmission, and a safe, effective gametocytocidal agent could also be used in community-wide malaria control programs. Here, we identify 15 small molecules with nanomolar activity against late-stage gametocytes. Fourteen are diaminonaphthoquinones (DANQs), and one is a 2-imino-benzo[d]imidazole (IBI). One of the DANQs identified, SJ000030570, is a lead antimalarial candidate. In contrast, 94% of the 650 compounds tested are inactive against late-stage gametocytes. Consistent with the ineffectiveness of most approved antimalarials against gametocytes, of the 19 novel compounds with activity against known anti-asexual-stage targets, only 3 had any strong effect on gametocyte viability. These data demonstrate the distinct biology of the transmission stages and emphasize the importance of screening for gametocytocidal activity. The potent gametocytocidal activity of DANQ and IBI coupled with their efficacy against asexual parasites provides leads for the development of antimalarials with the potential to prevent both the symptoms and the spread of malaria. PMID:25512421

Tanaka, Takeshi Q; Guiguemde, W Armand; Barnett, David S; Maron, Maxim I; Min, Jaeki; Connelly, Michele C; Suryadevara, Praveen Kumar; Guy, R Kiplin; Williamson, Kim C

2015-03-01

118

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 ...

119

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 ...

120

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

DOEpatents

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.

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

2014-09-30

121

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...

122

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

123

Tribological behaviour of new chemically bonded PTFE polyamide compounds  

Microsoft Academic Search

Topic of the study is the formation of new PTFE polyamide materials by reactive extrusion. The new type of formed PTFE polyamide compound shows very good material properties. Recently it has been revealed that carboxylic acid groups exhibit a very high reactivity under polyamide melting conditions. PTFE micro powders functionalized by carboxylic acid groups are the base for the block

Rainer Franke; Dieter Lehmann; Klaus Kunze

2007-01-01

124

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

125

Radiation induced chemical changes of phenolic compounds in strawberries  

NASA Astrophysics Data System (ADS)

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

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

2003-06-01

126

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

Microsoft Academic Search

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

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

2001-01-01

127

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

E-print Network

Quantitative detection of chemical compounds in human hair with coherent anti-Stokes Raman to selectively detect molecular agents in hair fibers is of direct relevance to understanding the chemical properties, such as tensile strength.1 For hair-color products the penetration of the dye precursors

Potma, Eric Olaf

128

CHEMICAL SPECIATION OF INORGANIC COMPOUNDS UNDER HYDROTHERMAL CONDITIONS  

EPA Science Inventory

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

129

Chemical composition and in vitro evaluation of antioxidant effect of free volatile compounds from Satureja montana L.  

PubMed

As a part of an investigation of natural antioxidants from Dalmatian aromatic plants, in this paper we report a study of the antioxidant activity related to the chemical composition of savory free volatile compounds. Twenty-one compounds were identified in the essential oil without fractionation, representing 97.4% of the total oil. The major compound was phenolic monoterpene thymol (45.2%). Other important compounds were monoterpenic hydrocarbons p-cymene (6.4%) a nd gamma-terpinene (5.9%)and oxygen-containing compounds carvacrol methyl ether (5.8%), thymol methyl ether (5.1%), carvacrol (5.3%), geraniol (5.0%) and borneol (3.9%). The evaluation of antioxidant power was performed in vitro by the beta-carotene bleaching and thiobarbituric acid (TBA) methods. As determined with both methods, the total savory essential oil as well as different fractions or pure constituents containing hydroxyl group exhibited relatively strong antioxidant effect. The hydrocarbons, when isolated as CH fraction, showed the poorest effectiveness in spite the fact that this fraction contained gamma-terpinene, alpha-terpinene, p-cymene and terpinolene which previously were identified as potential antioxidants. PMID:12868494

Radonic, Ani; Milos, Mladen

2003-06-01

130

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-7403, USA Abstract This paper describes a language for expressing criteria for chemical identification

Reichenbach, Stephen E.

131

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

ERIC Educational Resources Information Center

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

Cakmakci, Gultekin

2010-01-01

132

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

133

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

134

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

PubMed

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

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

2015-02-01

135

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

136

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; Fernández-Valle, Cristina

2014-01-01

137

Pupicidal and repellent activities of Pogostemon cablin essential oil chemical compounds against medically important human vector mosquitoes  

PubMed Central

Objective To determine the repellent and pupicidal activities of Pogostemon cablin (P. cablin) chemical compositions were assayed for their toxicity against selected important vector mosquitoes, viz., Aedes aegypti (Ae. aegypti), Anopheles stephensi (An. stephensi) and Culex quinquefasciatus (Cx. quinquefasciatus) (Diptera: Culicidae). Methods The plants dry aerial parts were subjected to hydrodistillation using a modified Clevenger-type apparatus. The composition of the essential oil was analyzed by Gas Chromatography (GC) and GC mass spectrophotometry. Evaluation was carried out in a net cage (45 cm×30 cm×45 cm) containing 100 blood starved female mosquitoes and were assayed in the laboratory condition by using the protocol of WHO 2010. The repellent activity of P. cablin chemical compositions at concentration of 2mg/cm2were applied on skin of fore arm in man and exposed against adult female mosquitoes. The pupicidal activity was determined against selected important vector mosquitoes to concentration of 100 mg/L and mortality of each pupa was recorded after 24 h of exposure to the compounds. Results Chemical constituents of 15 compounds were identified in the oil of P.cablin compounds representing to 98.96%. The major components in essential oil were â-patchoulene, á-guaiene, ã-patchoulene, á-bulnesene and patchouli alcohol. The repellent activity of patchouli alcohol compound was found to be most effective for repellent activity and 2 mg/cm2 concentration provided 100% protection up to 280 min against Ae. aegypti, An. stephensi and Cx. quinquefasciatus, respectively. Similarly, pupae exposed to 100 mg/L concentrations of P. cablin chemical compositions. Among five compounds tested patchouli alcoholwas found to be most effective for pupicidal activity provided 28.44, 26.28 and 25.36 against Ae.aegypti, An.stephensi and Cx. quinquefasciatus, respectively. The percent adult emergence was inversely proportional to the concentration of compounds and directly proportional to the pupal mortality. Conclusion These results suggest that the P. cablin chemical compositions have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes. This is the first report on the mosquito repellent and pupicidal activities of the reported P. cablin chemical compositions.

Gokulakrishnan, J; Kuppusamy, Elumalai; Shanmugam, Dhanasekaran; Appavu, Anandan; Kaliyamoorthi, Krishnappa

2013-01-01

138

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

PubMed Central

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

Moriguchi, I; Hirano, H; Hirono, S

1996-01-01

139

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

SciTech Connect

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

Moriguchi, Ikuo; Hirono, Shuichi [Kitasato Univ., Tokyo (Japan); Hirano, Hiroyuki [Zeria Pharmaceutical Co., Ltd., Tokyo (Japan)

1996-10-01

140

Nondestructive detection of hidden chemical compounds with laser Compton-scattering gamma rays.  

PubMed

A nondestructive assay method for measuring a shielded chemical compound has been proposed. The chemical compound is measured by using a nuclear resonance fluorescence (NRF) measurement technique with an energy tunable laser Compton-scattering (LCS) gamma-ray source. This method has an advantage that hidden materials can be detected through heavy shields such as iron plates of a thickness of several centimeters. A detection of a chemical compound of melamine, C(3)H(6)N(6), shielded by 15-mm-thick iron and 4-mm-thick lead plates is demonstrated. The NRF gamma-rays of (12)C and (14)N of the melamine are measured by using the LCS gamma-rays of the energies of up to 5.0 MeV. The observed ratio ((12)C/(14)N)(exp)=0.39+/-0.12 is consistent with (C/N)(melamine)=0.5. PMID:19405694

Hayakawa, Takehito; Ohgaki, Hideaki; Shizuma, Toshiyuki; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Minehara, Eisuke; Kii, Toshiteru; Toyokawa, Hiroyuki

2009-04-01

141

Improving solubitity and chemical stability of natural compounds for medicinal use by incorporation into liposomes  

Microsoft Academic Search

Natural bioactive compounds have been studied for a long time for their chemopreventive and therapeutic\\u000apotential in several chronic inflammatory diseases, including cancer. However, their physicochemical\\u000aproperties generally result in poor chemical stability and lack of in vivo bioavailability. Very few human\\u000aclinical trials have addressed absorption, distribution, metabolism, and excretion of these compounds in\\u000arelation to efficacy. This limits

M. J. Gomes Coimbra; B. Isacchi; L. van Bloois; J. Sastre Torano; A. Ket; X. Wu; F. Broere; J. M. Metselaar; C. J. F. Rijcken; G. Storm; R. Bilia; R. M. Schiffelers

2011-01-01

142

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

143

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

144

An isogenic cell panel identifies compounds that inhibit proliferation of mTOR-pathway addicted cells by different mechanisms.  

PubMed

The mTOR pathway is a critical integrator of nutrient and growth factor signaling. Once activated, mTOR promotes cell growth and proliferation. Several components of the mTOR pathway are frequently deregulated in tumors, leading to constitutive activation of the pathway and thus contribute to uncontrolled cell growth. We performed a high-throughput screen with an isogenic cell line system to identify compounds specifically inhibiting proliferation of PTEN/mTOR-pathway addicted cells. We show here the characterization and mode of action of two such compound classes. One compound class inhibits components of the PTEN/mTOR signaling pathway, such as S6 ribosomal protein phosphorylation, and leads to cyclin D3 downregulation. These compounds are not adenosine triphosphate competitive inhibitors for kinases in the pathway, nor do they require FKBP12 for activity like rapamycin. The other compound class turned out to be a farnesylation inhibitor, blocking the activity of GTPases, as well as an inducer of oxidative stress. Our results demonstrate that an isogenic cell system with few specific mutations in oncogenes and tumor suppressor genes can identify different classes of compounds selectively inhibiting proliferation of PTEN/mTOR pathway-addicted isogenic clones. The identified mechanisms are in line with the known cellular signaling networks activated by the altered oncogenes and suppressor genes in the isogenic system. PMID:23954931

Wyder Peters, Lorenza; Molle, Klaus D; Thiemeyer, Anke; Knopf, Agnes; Goxe, Marie; Guerry, Philippe; Brodbeck, Daniela; Colombi, Marco; Hall, Michael N; Moroni, Christoph; Regenass, Urs

2014-01-01

145

Identifying secondary structures in proteins using NMR chemical shift 3D correlation maps  

NASA Astrophysics Data System (ADS)

NMR chemical shifts are accurate indicators of molecular environment and have been extensively used as aids in protein structure determination. This work focuses on creating empirical 3D correlation maps of backbone chemical shift nuclei for use as identifiers of secondary structure elements in proteins. A correlated database of backbone nuclei chemical shifts was constructed from experimental structural data gathered from entries in the Protein Data Bank (PDB) as well as isotropic chemical shift values from the RefDB database. Rigorous statistical analysis of the maps led to the conclusion that specific correlations between triplets of backbone chemical shifts are best able to differentiate between different secondary structures such as ?-helices, ?-strands and turns. The method is compared with similar techniques that use NMR chemical shift information as aids in biomolecular structure determination and performs well in tests done on experimental data determined for different types of proteins, including large multi-domain proteins and membrane proteins.

Kumari, Amrita; Dorai, Kavita

2013-06-01

146

Chemical modulation of bioactive compounds via oligopeptide or amino acid conjugation.  

PubMed

Conjugation of an oligopeptide or an amino acid to bioactive compounds is one of the simplest chemical modifications to modulate the biological functions of the compounds. Recently, numerous methods have been proposed for the modification of their properties, including the alteration of their chemical and physical properties, and of their original bioactivities. We review the current knowledge of the adaptability of oligopeptide or amino acid conjugation for modulating the biological activities of biomolecules. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 584-591, 2013. PMID:23893824

Kwak, Seon-Yeong; Yang, Jin-Kyoung; Kim, Jong-Ho; Lee, Yoon-Sik

2013-11-01

147

Chemical compounds from the preanal gland secretions of the male tree agama (Acanthocercus atricollis) (fam. Agamidae).  

PubMed

Chemical signals have an important role in the reproductive behaviour of many lizards. However, the compounds secreted by their femoral or preanal glands, which may be used as sexual signals, are mainly known for lizard species within the Scleroglossa clade, whereas compounds in secretions of lizards within the Iguania clade are much less studied. Based on mass spectra, obtained by GC-MS, we found 60 lipophilic compounds in preanal gland secretions of the male tree agama (Acanthocercus atricollis) (fam. Agamidae), including steroids (mainly cholesterol, cholest-3-ene, and some of their derivatives), fatty acids ranging between n-C12 and n-C18 (mainly hexadecanoic and octadecenoic acids), ketones from n-C17 to n-C25, and other minor compounds, such as tocopherol, squalene, waxy esters, and furanones. We compare the compounds found with those present in other lizard species and discuss their potential function in social behaviour. PMID:23923623

Martín, José; Ortega, Jesús; López, Pilar

2013-01-01

148

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

Microsoft Academic Search

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

Mikhail M. Labushev

2011-01-01

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

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Incorporation of Physical-Chemical Identifiers Into Solid...incorporating physical-chemical identifiers (PCIDs...SODFs as a postapproval change. DATES: Submit either...SODFs as a postapproval change. Although not addressed...Incorporation of Physical-Chemical Identifiers Into...

2011-10-12

151

Compounds blocking mutant huntingtin toxicity identified using a Huntington's disease neuronal cell model.  

PubMed

Neuronal cell death in HD is believed to be largely a dominant cell-autonomous effect of the mutant huntingtin protein. We previously developed an inducible PC12 cell model which expresses an N-terminal huntingtin fragment with an expanded poly Q repeat (N63-148Q) under the control of the tet-off system. In order to evaluate the ability of compounds to protect against mutant huntingtin toxicity in our model, we measured LDH released by dead cells into the medium. We have now screened the library of 1040 compounds from the NINDS Custom Collection as part of a National Institute of Neurological Disorders and Stroke (NINDS) collaborative project. Each positive compound was tested at 3-8 concentrations. Five compounds significantly attenuated mutant huntingtin (htt)-induced LDH release without affecting the expression level of huntingtin and independent of effect on aggregates. We also tested a broad spectrum caspase inhibitor Z-VAD-fmk and previously proposed candidate compounds. This cell model can provide a method to screen potential therapeutic compounds for treating Huntington's disease. PMID:15908226

Wang, Wenfei; Duan, Wenzhen; Igarashi, Shuichi; Morita, Hokuto; Nakamura, Masayuki; Ross, Christopher A

2005-11-01

152

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

153

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

154

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

155

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

156

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

PubMed Central

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

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

2009-01-01

157

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

PubMed Central

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

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

1986-01-01

158

Identifying Mixed Chemical and Radioactive Waste Mixed waste is: any waste material containing both radioactive materials  

E-print Network

Identifying Mixed Chemical and Radioactive Waste Mixed waste is: any waste material containing both as noted on the list, you do not have a mixed waste and it may be managed as a normal radioactive waste radioactive waste after initially dating the container, the hold for decay time is extended, but you cannot

Straight, Aaron

159

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...

160

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

161

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

162

Identifying Source Soils in Contemporary Estuarine Sediments: A New Compound-Specific Isotope Method  

Microsoft Academic Search

A new method is proposed for the identification and apportionment of contemporary source soils contributing to estuarine sediments.\\u000a The method uses compound-specific isotopic analysis of naturally occurring biomarkers (fatty acids) derived from plants to\\u000a link source soils to land use within a single catchment. For identification and apportionment of source soils in the estuarine\\u000a samples, the method uses the isotopic

M. M. Gibbs

2008-01-01

163

Unbiased compound screening identifies unexpected drug sensitivities and novel treatment options for gastrointestinal stromal tumors.  

PubMed

Most gastrointestinal stromal tumors (GIST) are caused by oncogenic KIT or platelet-derived growth factor receptor activation, and the small molecule kinase inhibitor imatinib mesylate is an effective first-line therapy for metastatic or unresectable GIST. However, complete remissions are rare and most patients ultimately develop resistance, mostly because of secondary mutations in the driver oncogenic kinase. Hence, there is a need for novel treatment options to delay failure of primary treatment and restore tumor control in patients who progress under therapy with targeted agents. Historic data suggest that GISTs do not respond to classical chemotherapy, but systematic unbiased screening has not been performed. In screening a compound library enriched for U.S. Food and Drug Administration (FDA)-approved chemotherapeutic agents (NCI Approved Oncology Drugs Set II), we discovered that GIST cells display high sensitivity to transcriptional inhibitors and topoisomerase II inhibitors. Mechanistically, these compounds exploited the cells' dependency on continuous KIT expression and/or intrinsic DNA damage response defects, explaining their activity in GIST. Mithramycin A, an indirect inhibitor of the SP1 transcription factor, and mitoxantrone, a topoisomerase II inhibitor, exerted significant antitumor effects in mouse xenograft models of human GIST. Moreover, these compounds were active in patient-derived imatinib-resistant primary GIST cells, achieving efficacy at clinically relevant concentrations. Taken together, our findings reveal that GIST cells have an unexpectedly high and specific sensitivity to certain types of FDA-approved chemotherapeutic agents, with immediate implications for encouraging their clinical exploration. PMID:24385214

Boichuk, Sergei; Lee, Derek J; Mehalek, Keith R; Makielski, Kathleen R; Wozniak, Agnieszka; Seneviratne, Danushka S; Korzeniewski, Nina; Cuevas, Rolando; Parry, Joshua A; Brown, Matthew F; Zewe, James; Taguchi, Takahiro; Kuan, Shin-Fan; Schöffski, Patrick; Debiec-Rychter, Maria; Duensing, Anette

2014-02-15

164

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

165

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

166

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

167

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

168

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

SciTech Connect

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

Wahl, Jon H.; Colburn, Heather A.

2009-10-29

169

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

170

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

171

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.

172

Predictive performance of the Short Time Exposure test for identifying eye irritation potential of chemical mixtures.  

PubMed

The Short Time Exposure (STE) test is an in vitro eye irritation test based on the cytotoxicity in SIRC cells (rabbit corneal cell line) following a 5min treatment of chemicals. This study evaluated the predictive performance of the STE test to identify the globally harmonized system (GHS) Not Classified category and other irritant categories (i.e., GHS Category 1 or 2) when used to test 40 chemical mixtures that included irritants. The STE test correctly identified 30 tested mixtures classified as GHS irritant categories and 5 out of 10 tested mixtures classified as GHS Not Classified. The sensitivity, specificity, positive predictivity, negative predictivity, and overall accuracy of the STE test were 100% (30/30), 50% (5/10), 86% (25/30), 100% (5/5), and 88% (35/40), respectively. These predictive performances were comparative to or greater than those in other in vitro eye irritation tests that have been accepted as test guideline by the Organisation for Economic Co-operation and Development. This suggests that the STE test has sufficient predictivity for identifying the eye irritation potential of chemical mixtures. Since no false negatives in this study were found, this indicates that the STE test is applicable as a part of the bottom-up approach. PMID:25681760

Saito, Kazutoshi; Miyazawa, Masaaki; Nukada, Yuko; Ei, Kyo; Abo, Takayuki; Sakaguchi, Hitoshi

2015-04-01

173

Modulation of alternative splicing with chemical compounds in new therapeutics for human diseases.  

PubMed

Alternative splicing is a critical step where a limited number of human genes generate a complex and diverse proteome. Various diseases, including inherited diseases with abnormalities in the "genome code," have been found to result in an aberrant mis-spliced "transcript code" with correlation to the resulting phenotype. Chemical compound-based and nucleic acid-based strategies are trying to target this mis-spliced "transcript code". We will briefly mention about how to obtain splicing-modifying-compounds by high-throughput screening and overview of what is known about compounds that modify splicing pathways. The main focus will be on RNA-binding protein kinase inhibitors. In the main text, we will refer to diseases where splicing-modifying-compounds have been intensively investigated, with comparison to nucleic acid-based strategies. The information on their involvement in mis-splicing as well as nonsplicing events will be helpful in finding better compounds with less off-target effects for future implications in mis-splicing therapy. PMID:25560473

Ohe, Kenji; Hagiwara, Masatoshi

2015-04-17

174

Identifying competing aerobic nitrobenzene biodegradation pathways by compound-specific isotope analysis.  

PubMed

Nitroaromatic compounds that contaminate soil and groundwater can be biodegraded by different, sometimes competing reaction pathways. We evaluated the combined use of compound-specific stable C and N isotope analysis to distinguish between enzymatic nitrobenzene oxidation by Comamonas sp. strain JS765 and partial reduction by Pseudomonas pseudoalcaligenes strain JS45 under aerobic conditions. Bulk 13C and 15N enrichment factors for nitrobenzene dioxygenation with JS765 were -3.9 per thousand +/- 0.09 per thousand (+/- 1sigma) and -0.75 per thousand +/- 0.09 per thousand, respectively. The corresponding primary apparent kinetic isotope effects (AKIE) of 1.0241 +/- 0.0005 for 13C and a secondary 15N AKIE of 1.0008 +/- 0.0001 are in very good agreement with the proposed enzymatic addition of dioxygen to the aromatic ring to form a cis-dihydrodiol in the rate-limiting step of nitrobenzene degradation. For the partial reduction pathway with JS45, epsilonC and epsilonN values were -0.57 per thousand +/- 0.06 per thousand and -26.6 per thousand +/- 0.7 per thousand. The 13C and 15N AKIEs amount to 1.0034 +/- 0.0003 and 1.0273 +/- 0.0008, respectively, and are consistent with the two-electron reduction and dehydration of the aromatic NO2 group to nitrosobenzene. The combined evaluation of delta13C and delta15N changes in nitrobenzene, based on the isotope enrichment behavior found in this laboratory study, provide an excellent starting point for assessing of the extent of nitrobenzene biodegradation via competing pathways in contaminated environments. PMID:18678003

Hofstetter, Thomas B; Spain, Jim C; Nishino, Shirley F; Bolotin, Jakov; Schwarzenbach, Rene P

2008-07-01

175

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

176

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

177

K ? X-Ray Emission Spectra and Chemical Environments of Phosphorus in Some Selected Compounds  

NASA Astrophysics Data System (ADS)

The phosphorus K? emissionfluorescence spectra from10 selected compounds are measured with a high-resolution two-crystalvacuum spectrometer. The phosphorus compounds studied include inorganiccompounds K2HPO3, NaH2PO2·H2O, NaH2PO3·2.5H2O, Ca2P2O7, Cu2P2O7 and (NaPO3)6; and organic compoundstri-o-tolylphosphine (o-CH3C6H4)3P,tri-m-tolylphosphine (m-CH3C6H4)3P,tri-p-tolylphosphine (p-CH3C6H4)3P andtriphenylphosphine oxide (C6H5)3PO. The measured P K?emission spectra are discussed in relation to chemical environmentsaround phosphorus atom in the compounds. It is shown that the P K?emission spectra are strongly influenced by chemical environments. Theeffect of o-, m- and p-methyl substitution at the benzene ring(position isomerism) is observed in theemission spectra of tri-o-tolylphosphine, tri-m-tolylphosphineand tri-p-tolylphosphine.

Sugiura, Chikara; Yorikawa, Hiroharu; Muramatsu, Shinji

1996-09-01

178

[Quantification assessment of the relationship between chemical and olfactory concentrations for malodorous volatile organic compounds].  

PubMed

Using self-made cold-traps and gas bags, the odor samples were collected from 6 sewage treatment workshops of a typical municipal sewage treatment plant in Guangzhou City. The chemical composition and olfactory concentrations of these samples were respectively analyzed by thermal-desorption/GC-MS and triangle odor bag method. Finally, a mathematical equation was built for assessing the relationship between principal organic odorants and the olfactory concentrations. The result showing that: (1) More than 70 volatile organic compounds were detected in municipal sewage treatment plant, among which were 30 malodorous volatile organic compounds (MVOCs), ranging from 0.37 to 1 872.24 microg x m(-3) and appearing in sludge dewatering, thickening and aeration tank with the highest concentrations. (2) Principle component analysis was used to group the target MVOCs into 5 categories: benzenes, halohydrocarbons, aldehydes, hydrocarbons and S, N-containing organic compounds. (3) Multiple lineal regression analysis was used to build a quantified relationship between chemical and olfactory concentrations of MVOCs. The result indicated that 25% of the odor problem of sewage treatment unit was due to MVOCs. The predicted values were fitting well with measured values. The sensitivity of mathematical equation for measuring odor concentration was higher than that of human olfactory system. PMID:22468522

Liu, Shu-Le; Wang, Bo-Guang; He, Jie; Tang, Xiao-Dong; Zhao, De-Jun; Guo, Wei

2011-12-01

179

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

180

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

Microsoft Academic Search

An effects-directed strategy was applied to bed sediments of a polluted tributary in order to isolate and identify the major estrogenic chemicals it discharges into the River Po, the principal Italian watercourse. Sediment extract was concentrated by solid phase extraction and then fractioned into 10 fractions by reversed phase high performance liquid chromatography (RP-HPLC). Estrogenic activity of whole extract and

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

2008-01-01

181

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

182

93Nb and 17O NMR chemical shifts of niobiophosphate compounds.  

PubMed

Niobiophosphate compounds with a large range of niobium and oxygen environments were studied with (93)Nb and (17)O solid-state NMR. (93)Nb isotropic chemical shift of pure niobate Nb(ONb)(6), pure phosphate Nb(OP)(6) and mixed phosphate-niobate Nb(OP)(x)(ONb)((6-x)) (1chemical shifts were found to be sensitive to the variation of local charge on Nb, but not to the local bond geometry (i.e. crystallographic site and edge or corner connectivity). A systematic shift to high field of the (93)Nb chemical shift is measured when x increases. Then, (17)O NMR spectra of a series of enriched samples provided the chemical shift and quadrupolar parameters for 4 types of oxygen environment (P-O-P, P-O-Na, P-O-Nb and Nb-O-Nb). Finally, Nb-O-Nb sites were characterized by a large (17)O chemical shift anisotropy. PMID:17728114

Flambard, A; Montagne, L; Delevoye, L; Steuernagel, S

2007-10-01

183

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

PubMed Central

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

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

2014-01-01

184

PINS chemical identification software  

DOEpatents

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

Caffrey, Augustine J.; Krebs, Kennth M.

2004-09-14

185

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

186

Determination of octane numbers of gasoline compounds from their chemical structure by 13C NMR spectroscopy and neural networks  

Microsoft Academic Search

A new theoretical model has been developed which explains the association between the molecular structure and the knock resistance of individual gasoline compounds convincingly. The constitutions of more than 300 individual gasoline components were correlated with their knock rating (Blending Research Octane Number, BRON) simultaneously. 13C NMR spectra of all compounds were binned in 28 chemical shift regions of different

R. Meusinger; R. Moros

2001-01-01

187

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...

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

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

190

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

191

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

192

An FTIR point sensor for identifying chemical WMD and hazardous materials  

NASA Astrophysics Data System (ADS)

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

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

2004-03-01

193

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

PubMed

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

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

2012-04-01

194

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

SciTech Connect

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

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

2009-10-01

195

Identification of volatile and semivolatile compounds in chemical ionization GC-MS using a mass-to-structure (MTS) Search Engine with integral isotope pattern ranking.  

PubMed

The mass-to-structure or MTS Search Engine is an Access 2010 database containing theoretical molecular mass information for 19,438 compounds assembled from common sources such as the Merck Index, pesticide and pharmaceutical compilations, and chemical catalogues. This database, which contains no experimental mass spectral data, was developed as an aid to identification of compounds in atmospheric pressure ionization (API)-LC-MS. This paper describes a powerful upgrade to this database, a fully integrated utility for filtering or ranking candidates based on isotope ratios and patterns. The new MTS Search Engine is applied here to the identification of volatile and semivolatile compounds including pesticides, nitrosoamines and other pollutants. Methane and isobutane chemical ionization (CI) GC-MS spectra were obtained from unit mass resolution mass spectrometers to determine MH(+) masses and isotope ratios. Isotopes were measured accurately with errors of <4% and <6%, respectively, for A + 1 and A + 2 peaks. Deconvolution of interfering isotope clusters (e.g., M(+) and [M - H](+)) was required for accurate determination of the A + 1 isotope in halogenated compounds. Integrating the isotope data greatly improved the speed and accuracy of the database identifications. The database accurately identified unknowns from isobutane CI spectra in 100% of cases where as many as 40 candidates satisfied the mass tolerance. The paper describes the development and basic operation of the new MTS Search Engine and details performance testing with over 50 model compounds. PMID:23248816

Liao, Wenta; Draper, William M

2013-02-21

196

Application of an artificial neural network (ANN) and piezoelectric chemical sensor array for identification of volatile organic compounds.  

PubMed

A piezoelectric chemical sensor array was developed using four quartz crystals. Gas chromatographic stationary phases were used as sensing materials and the array was connected to an artificial neural network (ANN). The application of the ANN method proved to be particularly advantageous if the measured property (mass, concentration, etc.) should not be connected exactly to the signal of the transducers of the piezoelectric sensor. The optimum structure of neural network was determined by a trial and error method. Different structures were tried with several neurons in the hidden layer and the total error was calculated. The optimum values of primary weight factors, learning rate (eta=0.15), momentum term (mu=0.9), and the sigmoid parameter (beta=1) were determined. Finally, three hidden neurons and 900 training cycles were applied. After the teaching process the network was used for identification of taught analytes (acetone, benzene, chloroform, pentane). Mixtures of organic compounds were also analysed and the ANN method proved to be a reliable way of differentiating the sensing materials and identifying the volatile compounds. PMID:18966974

Barkó, G; Hlavay, J

1997-12-01

197

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

198

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

199

Triacylglycerols profiling as a chemical tool to identify mushrooms submitted to gamma or electron beam irradiation.  

PubMed

In order to define irradiation treatment as a routine conservation methodology, it is imperative to develop chemometric indicators with the ability to distinguish irradiated from unirradiated foodstuffs. Electron spin resonance, photostimulated luminescence and thermoluminescence methods were employed to monitor radiation-induced markers, as well as different chemical compounds produced from the lipidic fraction of different foodstuffs. Apart from these methods, the specificity of triacylglycerol profiles has previously been detected in mushroom species, as has the effect of irradiation treatment in the triacylglycerol profiles of chestnut. Accordingly, the feasibility of using this as a chemometric indicator of irradiated mushrooms was evaluated. In line with the obtained results in literature, the effects of each type of irradiation were significantly different, as can be concluded from the correlations among discriminant functions and variables within each statistical test. Triacylglycerol profiling proved to be a useful tool to detect irradiated mushrooms, independently of the species or irradiation source, especially for doses above 1 kGy. PMID:24767073

Fernandes, Ângela; Barreira, João C M; Antonio, Amilcar L; Martins, Anabela; Ferreira, Isabel C F R; Oliveira, M Beatriz P P

2014-09-15

200

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; Jönsson, Jan-Åke; Mayer, Philipp

2008-01-01

201

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

202

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. 6 figs.

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

1997-04-15

203

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

204

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

205

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

206

A chemical screen identifies class A G-protein coupled receptors as regulators of cilia  

PubMed Central

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 frequently 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.

2012-01-01

207

Chemicals identified in human biological media, a data base. First annual report, October 1979 (Records 1-1580)  

Microsoft Academic Search

A comprehensive data base of chemicals identified in human biological media (tissues and body fluids) has been established under the direction of the Environmental Protection Agency's Office of Toxic Substances Survey and Analysis Division. This centralized resource of body-burden information has grown out of the concern of government scientists over continuing reports of toxic chemicals in human tissues and body

M. V. Cone; M. F. Baldauf; F. M. Martin; J. T. Ensminger

1980-01-01

208

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

209

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

210

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

NASA Astrophysics Data System (ADS)

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

D'Agostino, Paul A.

211

Critical review of actually available chemical compounds for prevention and management of cyanobacterial blooms.  

PubMed

Cyanobacteria proliferation is among the most threatening consequences of freshwater pollution. Health risks from human and other-organism exposure to cyanobacteria have led to an effort to find practical methods for cyanobacterial water-bloom reduction. Hence, methods and techniques have been developed in order to reduce the amount of phosphorus or to decrease the abundance of nuisance phytoplankton species directly in the water bodies (in-lake measures). Although these "acute" methods do not solve the problem of catchment area eutrophication, they are cheaper, easier to manage, and for some areas they are the only way to protect human and environmental health against massive cyanobacterial proliferation. This review summarizes the extent of knowledge and published data about the management using metals (Al, Fe, Cu, Ag, Ca), photosensitizers (hydrogen peroxide, phthalocyanines, TiO(2)), herbicides and chemicals derived from natural compounds as fast and efficient removal agents of cyanobacteria. This review concludes that some compounds, when non-persistent and ecotoxicologically acceptable may help to manage cyanobacterial blooms in an efficient way compared to previous methods (e.g. copper sulfate). PMID:21925702

Jan?ula, Daniel; Maršálek, Blahoslav

2011-11-01

212

Catalytic Conversion of Carbon-Containing Compounds into Valuable Chemicals and Fuels  

NASA Astrophysics Data System (ADS)

Conversion of carbon-containing compounds, especially C1 compounds such as carbon dioxide and methane, to valuable chemicals and fuels will hopefully address concerns over decreasing supplies of fossil fuels and mitigate the eects of greenhouse gas emissions on global climate change. Many challenges, however, remain to be addressed before these technologies may be adopted on an industrial scale. Chiefly, catalysts must be developed to activate carbon-containing compounds from their thermodynamically stable ground states, using hydrogen, electrons, or heat as energy sources. We chose as model catalytic systems: 1) Metathesis of ethene and 2-butene; 2) Methane dehydrogenation and carbon dioxide hydrogenation. We developed three computational methodologies to study these processes across a range of length and time scales. First, we investigated how electronic structure affects the properties and reactivity of these catalyst systems; by computing the partial electronic density of states, electronic localization function, and excess spin density, we showed how redox supports, such as ceria, promote electron transfer reactions. We applied this to the studies of methane activation and carbon dioxide activation. Second, we developed a non-equilibrium thermodynamics approach to calculate energies of activation at nite temperatures, based on the Bronsted-Evans-Polanyi principle and the Nudged Elastic Band method. Third, we developed an approach to numerically compute heat capacities and other thermodynamic properties on extended catalytic systems that are comparable in accuracy and precision to methods that have been well-developed for gas-phase molecules. We applied these to the studies of metathesis propagation and carbon dioxide hydrogenation. We gained mechanistic, thermodynamic, and kinetic insight into the elementary steps that comprise larger reaction networks of interest to the broader catalysis community. Ultimately, these theoretical and computational predictions can be used to guide experimental design, synthesis, and characterization of new catalyst systems.

Cheng, Zhuo

213

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

214

Chemical genetics approach to restoring p27Kip1 reveals novel compounds with antiproliferative activity in prostate cancer cells  

PubMed Central

Background The cyclin-dependent kinase (CDK) inhibitor p27Kip1 is downregulated in a majority of human cancers due to ectopic proteolysis by the ubiquitin-proteasome pathway. The expression of p27 is subject to multiple mechanisms of control involving several transcription factors, kinase pathways and at least three different ubiquitin ligases (SCFSKP2, KPC, Pirh2), which regulate p27 transcription, translation, protein stability and subcellular localization. Using a chemical genetics approach, we have asked whether this control network can be modulated by small molecules such that p27 protein expression is restored in cancer cells. Results We developed a cell-based assay for measuring the levels of endogenous nuclear p27 in a high throughput screening format employing LNCaP prostate cancer cells engineered to overexpress SKP2. The assay platform was optimized to Z' factors of 0.48 - 0.6 and piloted by screening a total of 7368 chemical compounds. During the course of this work, we discovered two small molecules of previously unknown biological activity, SMIP001 and SMIP004, which increase the nuclear level of p27 at low micromolar concentrations. SMIPs (small molecule inhibitors of p27 depletion) also upregulate p21Cip1, inhibit cellular CDK2 activity, induce G1 delay, inhibit colony formation in soft agar and exhibit preferential cytotoxicity in LNCaP cells relative to normal human fibroblasts. Unlike SMIP001, SMIP004 was found to downregulate SKP2 and to stabilize p27, although neither SMIP is a proteasome inhibitor. Whereas the screening endpoint - nuclear p27 - was robustly modulated by the compounds, SMIP-mediated cell cycle arrest and apoptosis were not strictly dependent on p27 and p21 - a finding that is explained by parallel inhibitory effects of SMIPs on positive cell cycle regulators, including cyclins E and A, and CDK4. Conclusions Our data provide proof-of-principle that the screening platform we developed, using endogenous nuclear p27 as an endpoint, presents an effective means of identifying bioactive molecules with cancer selective antiproliferative activity. This approach, when applied to larger and more diverse sets of compounds with refined drug-like properties, bears the potential of revealing both unknown cellular pathways globally impinging on p27 and novel leads for chemotherapeutics targeting a prominent molecular defect of human cancers. PMID:21182779

2010-01-01

215

Design of a system for storing and predicting physico-chemical properties for compounds and mixtures dealing with pharmaceutical chemistry  

Microsoft Academic Search

In-house Data Bank for storing a large variety of physico-chemical properties, names, formulae and other characteristics of compounds and mixtures dealing with fine and pharmaceutical chemistry was developed for personnel computers (PCs).Among the large quantity and variety of existing estimation methods the more appropriate ones were selected for each property. These selected methods offered the best results for pure compounds

Eladio Pardillo; Jorge Marrero; Alejandro Suárez; Ulises Jáuregui; Silvia Fernández; Rubèn Frederick

1997-01-01

216

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 ...

217

Characterization of Sources and Chemical Transformations of Volatile Organic Compounds (Invited)  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) are directly emitted from natural and anthropogenic sources, as well as chemically produced in the atmosphere. The emission rates of VOCs are not as well understood as other gases (e.g., CO, NOx), but play an important role in determining ozone production rates and formation of secondary organic aerosols (SOA). Many recent field experiments have included comprehensive measurements of VOCs in a variety of environments. This study will focus on observations from the Deep Convective Cloud and Chemistry (DC3) experiment (May-June 2012), which included sampling of air influenced by emissions from vegetation, oil and gas extraction and wildfires from the NSF GV and NASA DC-8 aircraft. Observations from aircraft during other experiments will also be used, such as the NASA DC-8 during the ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) experiment (Spring and Summer 2008), and the NSF C-130 during the NOMADSS (Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks) experiment (June-July 2013). These observations are used to evaluate model simulations from the Community Atmosphere Model with Chemistry (CAM-chem), a component of the NCAR Community Earth System Model. Through comparison of VOC/CO ratios between observations and models near source regions, the emission inventories are evaluated. The chemical evolution of VOCs, in particular the formation of oxidized species such as formaldehyde, acetaldehyde and acetone, are studied.

Emmons, L. K.; Apel, E. C.; Hornbrook, R. S.; Blake, N. J.; Blake, D. R.; Guenther, A. B.; Kaser, L.; Yuan, B.; De Gouw, J. A.

2013-12-01

218

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

219

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

220

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

221

Development of a surface acoustic wave gas sensor for organophosphorus nerve agents employing lanthanide compounds as the chemical interface.  

PubMed

The results of a study dealing with surface acoustic wave gas sensors for organophosphorus compounds such as nerve agents are described. Several lanthanum coordination compounds were applied as the chemical interface. The various sensors prepared were challenged with both the nerve agent sarin and the simulant dimethyl methylphosphonate. Many aspects were studied, such as sensitivity, selectivity, reversibility and response rate as well as the effect of temperature and structural features. Detection limits down to 0.1 ppm were found. Response rates require further improvement. Degradation phenomena were observed which in some cases yielded irreversible responses. The selectivity for organophosphorus compounds was found to be promising. PMID:18965951

Nieuwenhuizen, M S; Harteveld, J L

1994-03-01

222

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

223

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

224

Chemical Genetics Identify eIF2? Kinase Heme Regulated Inhibitor as Anti-Cancer Target  

PubMed Central

Translation initiation plays a critical role in cellular homeostasis, proliferation, differentiation and malignant transformation. Consistently, increasing the abundance of the eIF2·GTP·Met-tRNAi translation initiation complex transforms normal cells and contributes to cancer initiation and the severity of some anemia. The chemical modifiers of the eIF2·GTP·Met-tRNAi ternary complex are therefore invaluable tools for studying its role in the pathobiology of human disorders and for determining if this complex can be pharmacologically targeted for therapeutic purposes. Using a cell based assay, we identified N,N’-diarylureas as novel inhibitors of the ternary complex abundance. Direct functional-genetics and biochemical evidence demonstrated that the N,N’-diarylureas activate heme regulated inhibitor kinase, thereby phosphorylate eIF2? and reduce abundance of the ternary complex. Using tumor cell proliferation in vitro and tumor growth in vivo as paradigms, we demonstrate that N,N’-diarylureas are potent and specific tools for studying the role eIF2·GTP·Met-tRNAi ternary complex in the pathobiology of human disorders. PMID:21765405

Chen, Ting; Ozel, Duygu; Qiao, Yuan; Harbinski, Fred; Chen, Limo; Denoyelle, Séverine; He, Xiaoying; Zvereva, Nela; Supko, Jeffrey G.; Chorev, Michael; Halperin, Jose A.; Aktas, Bertal H.

2013-01-01

225

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...

226

A Novel System for Rapidly Identifying Toxic Chemicals Suresh K. Bhavnani1,2  

E-print Network

chemicals is critical for saving lives in emergency situations ranging from terrorist attacks to chemical-test). Conclusion and Future Research A demonstration and the source code for our prototype have been provided chemicals during emergencies. In our future research we plan to test that hypothesis through a comprehensive

Bhavnani, Suresh K.

227

A Novel System for Rapidly Identifying Toxic Chemicals Suresh K. Bhavnani1,2  

E-print Network

chemicals is critical for saving lives in emergency situations ranging from terrorist attacks to chemical-test). Conclusion and Future Research A demonstration and the source code for our prototype has been provided chemicals during emergencies. In our future research we plan to test that hypothesis through a comprehensive

Scott, Clayton

228

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

229

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

PubMed

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

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

2015-01-21

230

Characterization of Pellicle Inhibition in Gluconacetobacter xylinus 53582 by a Small Molecule, Pellicin, Identified by a Chemical Genetics Screen  

PubMed Central

Pellicin ([2E]-3-phenyl-1-[2,3,4,5-tetrahydro-1,6-benzodioxocin-8-yl]prop-2-en-1-one) was identified in a chemical genetics screen of 10,000 small molecules for its ability to completely abolish pellicle production in Gluconacetobacter xylinus. Cells grown in the presence of pellicin grew 1.5 times faster than untreated cells. Interestingly, growth in pellicin also caused G. xylinus cells to elongate. Measurement of cellulose synthesis in vitro showed that cellulose synthase activity was not directly inhibited by pellicin. Rather, when cellulose synthase activity was measured in cells that were pre-treated with the compound, the rate of cellulose synthesis increased eight-fold over that observed for untreated cells. This phenomenon was also apparent in the rapid production of cellulose when cells grown in the presence of pellicin were washed and transferred to media lacking the inhibitor. The rate at which cellulose was produced could not be accounted for by growth of the organism. Pellicin was not detected when intracellular contents were analyzed. Furthermore, it was found that pellicin exerts its effect extracellularly by interfering with the crystallization of pre-cellulosic tactoidal aggregates. This interference of the crystallization process resulted in enhanced production of cellulose II as evidenced by the ratio of acid insoluble to acid soluble product in in vitro assays and confirmed in vivo by scanning electron microscopy and powder X-ray diffraction. The relative crystallinity index, RCI, of pellicle produced by untreated G. xylinus cultures was 70% while pellicin-grown cultures had RCI of 38%. Mercerized pellicle of untreated cells had RCI of 42%, which further confirms the mechanism of action of pellicin as an inhibitor of the cellulose I crystallization process. Pellicin is a useful tool for the study of cellulose biosynthesis in G. xylinus. PMID:22174763

Strap, Janice L.; Latos, Andrew; Shim, Isaac; Bonetta, Dario T.

2011-01-01

231

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

NASA Astrophysics Data System (ADS)

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

Xin, Le

232

Chemical Characterization of Secondary Organic Aerosol Formed from Atmospheric Aqueous-phase Reactions of Phenolic Compounds  

NASA Astrophysics Data System (ADS)

Phenolic compounds, which are released in significant amounts from biomass burning, may undergo fast aqueous-phase reactions to form secondary organic aerosol (SOA) in the atmosphere. Understanding the aqueous-phase reaction mechanisms of these compounds and the composition of their reaction products is thus important for constraining SOA sources and predicting organic aerosol properties in models. In this study, we investigate the aqueous-phase reactions of three phenols (phenol, guaiacol and syringol) with two oxidants - excited triplet states (3C*) of non-phenolic aromatic carbonyls and hydroxyl radical (OH). By employing four analytical methods including high-resolution aerosol mass spectrometry, total organic carbon analysis, ion chromatography, and liquid chromatography-mass spectrometry, we thoroughly characterize the chemical compositions of the low volatility reaction products of phenols and propose formation mechanisms based on this information. Our results indicate that phenolic SOA is highly oxygenated, with O/C ratios in the range of 0.83-1.03, and that the SOA of phenol is usually more oxidized than those of guaiacol and syringol. Among the three precursors, syringol generates the largest fraction of higher molecular weight (MW) products. For the same precursor, the SOA formed via reaction with 3C* is less oxidized than that formed via reaction with OH. In addition, oxidation by 3C* enhances the formation of higher MW species, including phenolic dimers, higher oligomers and hydroxylated products, compared to reactions initiated by OH, which appear to favor the formation of organic acids. However, our results indicate that the yields of small organic acids (e.g., formate, acetate, oxalate, and malate) are low for both reaction pathways, together accounting for less than 5% of total SOA mass.

Yu, L.; Smith, J.; Anastasio, C.; Zhang, Q.

2012-12-01

233

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

234

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

PubMed Central

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

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

2015-01-01

235

Establishment of a Cell-Based Assay for Screening of Compounds Inhibiting Very Early Events in the Cytomegalovirus Replication Cycle and Characterization of a Compound Identified Using the Assay  

Microsoft Academic Search

To simplify the detection of infectious human cytomegalovirus (HCMV), we generated a cell line that produced luciferase in a dose-dependent manner upon HCMV infection. Using this cell line, we identified anti-HCMV compounds from a diverse library of 9,600 compounds. One of them, 1-(3,5-dichloro-4-pyridyl)pi- peridine-4-carboxamide (DPPC), was effective against HCMV (Towne strain) infection of human lung fibro- blast cells at a

Yoshiko Fukui; Keiko Shindoh; Yumiko Yamamoto; Shin Koyano; Isao Kosugi; Toyofumi Yamaguchi; Ichiro Kurane; Naoki Inoue

2008-01-01

236

Screening method to identify preclinical liquid and semi-solid formulations for low solubility compounds: miniaturization and automation of solvent casting and dissolution testing.  

PubMed

We have developed an efficient screening method to identify liquid and semisolid formulations for low-solubility compounds. The method is most suitable for identifying dosing vehicles for compounds in lead optimization, where compound supply is limited and long-term stability is not a requirement. Dilute compound and excipient stock solutions are prepared in organic solvent and then dispensed and mixed in 96-well plates. The solvent is removed in a vacuum centrifuge evaporator, leaving neat formulation (e.g., 10-40 microg compound, 0.4 mg excipient) at the bottom of each well. After an aging step, an aqueous dilution medium is added and the plates are incubated (agitation by orbital shaking). The diluted formulations are then filtered and analyzed by ultraviolet (UV) absorbance or high-performance liquid chromatography (HPLC). To illustrate the method, two compounds (aqueous solubility compound/surfactant/oil formulations is also presented. PMID:17094139

Mansky, Paul; Dai, Wei-Guo; Li, Shu; Pollock-Dove, Crystal; Daehne, Klaus; Dong, Liang; Eichenbaum, Gary

2007-06-01

237

Two-Dimensional Carbon Compounds Derived from Graphyne with Chemical Properties Superior to Those of Graphene  

PubMed Central

Computational studies considering both thermodynamic and kinetic aspects revealed that graphyne, a carbon material that has recently been of increasing interest, favours unprecedented homogeneous “in-plane” addition reactions. The addition of dichlorocarbene to the C(sp)-C(sp) bond, a site with outstanding regioselectivity in graphyne, proceeds via a stepwise mechanism. Due to their homogeneous nature, additions occurring at C(sp)-C(sp) bonds yield structurally ordered two-dimensional carbon compounds (2DCCs). 2DCCs have electronic band structures near the Fermi level that are similar to those of graphene and are either electrically semi-conductive or metallic depending on whether the reactions break the hexagonal symmetry. Notably, 2DCCs can be further functionalised through substitution reactions with little damage to the extended ?-electron conjugation system. These results suggest that 2DCCs derived from graphyne have physical properties comparable to those of graphene and chemical properties superior to those of graphene. Therefore, 2DCCs are expected to be better suited to practical applications. PMID:23429350

Zheng, Jia-Jia; Zhao, Xiang; Zhao, Yuliang; Gao, Xingfa

2013-01-01

238

Nature of the chemical bond and prediction of radiation tolerance in pyrochlore and defect fluorite compounds  

SciTech Connect

The radiation tolerance of synthetic pyrochlore and defect fluorite compounds has been studied using ion irradiation. We show that the results can be quantified in terms of the critical temperature for amorphization, structural parameters, classical Pauling electronegativity difference, and disorder energies. Our results demonstrate that radiation tolerance is correlated with a change in the structure from pyrochlore to defect fluorite, a smaller unit cell dimension, and lower cation-anion disorder energy. Radiation tolerance is promoted by an increase in the Pauling cation-anion electronegativity difference or, in other words, an increase in the ionicity of the chemical bonds. A further analysis of the data indicates that, of the two possible cation sites in ideal pyrochlore, the smaller B-site cation appears to play the major role in bonding. This result is supported by ab initio calculations of the structure and bonding, showing a correlation between the Mulliken overlap populations of the B-site cation and the critical temperature. - Graphical abstract: Three-dimensional representation of the predicted critical amorphization temperature in pyrochlores.

Lumpkin, Gregory R. [Cambridge Centre for Ceramic Immobilisation, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Institute of Materials and Engineering Science, Australian Nuclear Science and Technology Organisation, Private Mail Bag 1, Menai, NSW 2234 (Australia)], E-mail: grl@ansto.gov.au; Pruneda, Miguel [Cambridge Centre for Ceramic Immobilisation, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Rios, Susana [Cambridge Centre for Ceramic Immobilisation, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Smith, Katherine L. [Institute of Materials and Engineering Science, Australian Nuclear Science and Technology Organisation, Private Mail Bag 1, Menai, NSW 2234 (Australia); Trachenko, Kostya [Cambridge Centre for Ceramic Immobilisation, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Whittle, Karl R. [Cambridge Centre for Ceramic Immobilisation, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Department of Engineering Materials, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom); Zaluzec, Nestor J. [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

2007-04-15

239

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

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; Hata, Yutaka

2014-05-01

240

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

241

Biogeographical analysis of chemical co-occurrence data to identify priorities for mixtures research.  

PubMed

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, testing of chemical interaction more often comprises ad hoc binary combinations and rarely examines higher order combinations. One explanation for this practice is the belief that there are simply too many possible combinations of chemicals to consider. Indeed, under stochastic conditions the possible number of chemical combinations scales geometrically as the pool of chemicals increases. However, the occurrence of chemicals in the environment is determined by factors, economic in part, which favor some chemicals over others. We investigate methods from the field of biogeography, originally developed to study avian species co-occurrence patterns, and adapt these approaches to examine chemical co-occurrence. These methods were applied to a national survey of pesticide residues in 168 child care centers from across the country. Our findings show that pesticide co-occurrence in the child care center was not random but highly structured, leading to the co-occurrence of specific pesticide combinations. Thus, ecological studies of species co-occurrence parallel the issue of chemical co-occurrence at specific locations. Both are driven by processes that introduce structure in the pattern of co-occurrence. We conclude that the biogeographical tools used to determine when this structure occurs in ecological studies are relevant to evaluations of pesticide mixtures for exposure and risk assessment. PMID:21801190

Tornero-Velez, Rogelio; Egeghy, Peter P; Cohen Hubal, Elaine A

2012-02-01

242

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...

243

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

244

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

245

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...

246

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

247

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...

248

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

249

Identifiers Identifiers  

E-print Network

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

Brass, Stefan

250

Identifiers Identifiers  

E-print Network

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

Brass, Stefan

251

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

PubMed

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

Shi, Yujun

2015-02-17

252

Collisionally activated dissociation and electron capture dissociation of several mass spectrometry-identifiable chemical cross-linkers.  

PubMed

One of the challenges in protein interaction studies with chemical cross-linking stems from the complexity of intra-, inter-, and dead-end cross-linked peptide mixtures. We have developed new cross-linkers to study protein-protein interactions with mass spectrometry to improve the ability to deal with this complexity. Even the accurate mass capabilities of FTICR-MS alone cannot unambiguously identify cross-linked peptides from cell-labeling experiments due to the complexity of these mixtures resultant from the enormous number of possible cross-linked species. We have developed novel cross-linkers that have unique fragmentation features in the gas phase. The characteristics of these cross-linkers combined with the accurate mass capability of FTICR-MS can help distinguish cross-linking reaction products and assign protein identities. These cross-linkers that we call protein interaction reporters (PIRs) have been constructed with two reactive groups attached through two bonds that can be preferentially cleaved by low-energy CID of the respective protonated precursor ions. After cleavage of the labile bonds, the middle part of the linker serves as a reporter ion to aid identification of cross-linked peptides. This report highlights three new PIRs with new features that have been developed to improve the efficiency of release of reporter ions. The new cross-linkers reported here were tuned with the addition of an affinity tag, a hydrophilic group, a photocleavable group, and new low-energy MS/MS cleavable bonds. This report presents our investigation of the MSMS fragmentation behavior of selected protonated ions of the new compounds. The comprehensive fragmentation of these PIRs and PIR-labeled cross-linked peptides with low-energy collisions and an example of electron capture dissociation in FTICR-MS is presented. These new cross-linkers will contribute to current systems biology research by allowing acquisition of global or large-scale data on protein-protein interactions. PMID:17165806

Chowdhury, Saiful M; Munske, Gerhard R; Tang, Xiaoting; Bruce, James E

2006-12-15

253

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

Microsoft Academic Search

BackgroundPraziquantel (PZQ) is the only widely available drug to treat schistosomiasis. Given the potential for drug resistance, it is prudent to search for novel therapeutics. Identification of anti-schistosomal chemicals has traditionally relied on phenotypic (whole organism) screening with adult worms in vitro and\\/or animal models of disease—tools that limit automation and throughput with modern microtiter plate-formatted compound libraries.MethodsA partially automated,

Maha-Hamadien Abdulla; Debbie S. Ruelas; Brian Wolff; June Snedecor; Kee-Chong Lim; Fengyun Xu; Adam R. Renslo; Janice Williams; James H. McKerrow; Conor R. Caffrey

2009-01-01

254

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

255

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

SciTech Connect

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

Wang, Jing; Liang, Le [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Lanting, E-mail: lantingzh@sjtu.edu.cn, E-mail: lmsun@sjtu.edu.cn [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Hirano Institute for Materials Innovation, Shanghai Jiao Tong University, Shanghai 200240 (China); Sun, Limin, E-mail: lantingzh@sjtu.edu.cn, E-mail: lmsun@sjtu.edu.cn [Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Hirano, Shinichi [Hirano Institute for Materials Innovation, Shanghai Jiao Tong University, Shanghai 200240 (China)

2014-10-28

256

cDNA phage display as a novel tool to screen for cellular targets of chemical compounds  

Microsoft Academic Search

cDNA phage display is frequently used in drug development to screen for cellular target of drugs. However, in toxicology, cDNA phage display remains unexplored, although it has large potential in this field. In this study, cDNA phage display is demonstrated as a novel tool to screen for interactions between chemical compounds and cellular targets. The knowledge of these target interactions

Bieke Van Dorst; Jaytry Mehta; Elsa Rouah-Martin; Veerle Somers; Wim De Coen; Ronny Blust; Johan Robbens

2010-01-01

257

Case-control study of multiple chemical sensitivity, comparing haematology, biochemistry, vitamins and serum volatile organic compound measures  

Microsoft Academic Search

Background Multiple chemical sensitivity (MCS), although poorly understood, is associated with considerable morbidity. Aim To investigate potential biological mechanisms underlying MCS in a case-control study. Methods Two hundred and twenty-three MCS cases and 194 controls (urban females, aged 30-64 years) fulfilled reproducible eligibility criteria with discriminant validity. Routine laboratory results and serum levels of volatile organic compounds (VOCs) were compared.

Cornelia Johanna Baines; Gail Elizabeth; Nicole Riley; David Edward; C. Cole; Lynn Marshall; Barry Loescher; Vartouhi Jazmaji

258

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

259

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

260

The FASEB Journal Research Communication Chemical and metabolomic screens identify novel  

E-print Network

. Rockwood,# Calum A. MacRae, Matthew Brenner,§ Robert E. Gerszten,*,, and Randall T. Peterson*,,,2, G. R., Rockwood, G. A., MacRae, C. A., Brenner, M., Gerszten, R. E., Peterson, R. T. Chemical requirements, such as the brain and heart (1). Cyanide exposure can occur as a consequence of smoke inhalation

Chen, Zhongping

261

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...

262

Gas chromatography plasma-assisted reaction chemical ionization mass spectrometry for quantitative detection of bromine in organic compounds.  

PubMed

We have recently introduced plasma-assisted reaction chemical ionization mass spectrometry (PARCI-MS) for elemental analysis of halogens in organic compounds. Here, we utilize gas chromatography (GC) coupled to PARCI-MS to investigate the mechanism of Br(-) ion generation from organobromines and to evaluate analytical performance of PARCI for organobromine analysis. Bromine atoms in compounds eluting from GC are converted to HBr in a low-pressure microwave induced helium plasma with trace amounts of hydrogen added as a reaction gas. Ionization is achieved by introducing nitrogen into the afterglow region of the plasma, liberating electrons via penning ionization and leading to formation of negative ions. We demonstrate that N2 largely affects the ionization process, whereas H2 affects both the ionization process and in-plasma reactions. Our investigations also suggest that dissociative electron capture is the main ionization route for formation of Br(-) ions. Importantly, GC-PARCI-MS shows a uniform response factor for bromine across brominated compounds of drastically different chemical structures, confirming PARCI's ability to quantify organobromines in the absence of compound-specific standards. Over 3 orders of magnitude linear dynamic range is demonstrated for bromine quantification. We report a detection limit of 29 fg of bromine on-column, ~4-fold better than inductively coupled plasma-MS. PMID:25003497

Lin, Ninghang; Wang, Haopeng; Kahen, Kaveh; Badiei, Hamid; Jorabchi, Kaveh

2014-08-01

263

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

264

Estrogenic Activity Assessment of Environmental Chemicals Using in Vitro Assays: Identification of Two New Estrogenic Compounds  

Microsoft Academic Search

Environmental chemicals with estrogenic activities have been suggested to be associated with deleterious effects in animals and humans. To characterize estrogenic chemicals and their mecha- nisms of action, we established in vitro and cell culture assays that detect human estrogen recep- tor ? (hER?)-mediated estrogenicity. First, we assayed chemicals to determine their ability to modulate direct interaction between the hER?

Isabelle Lascombe; Dominique Beffa; Urs Rüegg; Joseph Tarradellas; Walter Wahli

265

Attempts to identify a control system for chemical reactivity in the living state using virtual energy.  

PubMed

This thesis explores the activation of chemicals in metabolic systems from the viewpoint that this activation is under the control of elements of the space-sea in which the chemicals are immersed. Themselves inert, the chemicals are theorised to exploit a force or action issuing from space (fluctuation) and characterized by the homogeneity (termed symmetry) of this medium. The fluctuation is heterogenized upon collision with matter from the intervention of well recognized fields of gravity and electromagnetism at the instant of its issue to form the near field of radiation. Fractions of original space waves and of their intrinsic spin are produced resulting in the activation of the orbitals (valency) in the chemical itself. The thesis continues: the disturbed fluctuation must return to space, obliging in turn, a prior return to the homogeneous state requiring special restorative wave rearrangements known as resonance. The success of the restorative resonance is signalled by a singularity of the fluctuation now propelled to infinity (space), and the contingent chemical reactions thereby terminated. Compromise to this return can occur from many causes and, in its presence, activation of the orbitals continues. They now effectively constitute autonomous reactions alienated from the system as a whole. The thesis is supported from evidence from diverse fields such as space theory, history of quantum field theory in attempts to derive its meaning, dielectrics and the near field of electromagnetic radiation, electron-space interactions at the Fermi surface during phase transitions and evolution of equilibrium conditions in resonance phenomena. The utility of the hypothesis rests on recognition of the resonance condition at various points in the system sufficiently macroscopic as to be available clinically as an abrupt interface between physiology and pathology. PMID:11421620

Reid, B L; Bourke, C

2001-07-01

266

Enhancing of chemical compound and drug name recognition using representative tag scheme and fine-grained tokenization  

PubMed Central

Background The functions of chemical compounds and drugs that affect biological processes and their particular effect on the onset and treatment of diseases have attracted increasing interest with the advancement of research in the life sciences. To extract knowledge from the extensive literatures on such compounds and drugs, the organizers of BioCreative IV administered the CHEMical Compound and Drug Named Entity Recognition (CHEMDNER) task to establish a standard dataset for evaluating state-of-the-art chemical entity recognition methods. Methods This study introduces the approach of our CHEMDNER system. Instead of emphasizing the development of novel feature sets for machine learning, this study investigates the effect of various tag schemes on the recognition of the names of chemicals and drugs by using conditional random fields. Experiments were conducted using combinations of different tokenization strategies and tag schemes to investigate the effects of tag set selection and tokenization method on the CHEMDNER task. Results This study presents the performance of CHEMDNER of three more representative tag schemes-IOBE, IOBES, and IOB12E-when applied to a widely utilized IOB tag set and combined with the coarse-/fine-grained tokenization methods. The experimental results thus reveal that the fine-grained tokenization strategy performance best in terms of precision, recall and F-scores when the IOBES tag set was utilized. The IOBES model with fine-grained tokenization yielded the best-F-scores in the six chemical entity categories other than the "Multiple" entity category. Nonetheless, no significant improvement was observed when a more representative tag schemes was used with the coarse or fine-grained tokenization rules. The best F-scores that were achieved using the developed system on the test dataset of the CHEMDNER task were 0.833 and 0.815 for the chemical documents indexing and the chemical entity mention recognition tasks, respectively. Conclusions The results herein highlight the importance of tag set selection and the use of different tokenization strategies. Fine-grained tokenization combined with the tag set IOBES most effectively recognizes chemical and drug names. To the best of the authors' knowledge, this investigation is the first comprehensive investigation use of various tag set schemes combined with different tokenization strategies for the recognition of chemical entities.

2015-01-01

267

Histamine release inhibition in vitro and antianaphylactic effects in vivo of some chemical compounds  

PubMed Central

Several different types of compounds inhibited the release of histamine from the “platelet fraction” of rabbit blood when antigen was added to the blood of a sensitized rabbit in vitro. These compounds were all very toxic in vivo and could be tested only at low levels for their ability to protect animals against anaphylaxis. None of the compounds gave significant protection to sensitized animals when antigen was given intravenously. Three compounds protected animals against antigen administered as an aerosol. None of these showed any promise of clinical usefulness. Of a number of compounds which have been reported to alleviate allergic symptoms, or to protect against anaphylaxis, none prevented the release of histamine in vitro to any considerable extent. PMID:13413149

McIntire, F. C.; Richards, R. K.; Roth, L. W.

1957-01-01

268

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

269

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

270

Chemical reactivity of hypervalent silicon compounds: The local hard and soft acids and bases principle viewpoint  

Microsoft Academic Search

The silicon atom may increase its coordination number to values greater than four, to form pentacoordinated compounds. It\\u000a has been observed experimentally that, in general, pentacoordinated compounds show greater reactivity than tetracoordinated\\u000a compounds. In this work, density functional theory is used to calculate the global softness and the condensed softness of\\u000a the silicon atom for SiH\\u000a n\\u000a F4?n\\u000a and SiH

Francisco Méndez; María De L. Romero; José L. Gazquez

2005-01-01

271

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

PubMed

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

Rout, Soumya P; Kar, Durga M

2014-01-01

272

Implementation and performance evaluation of a database of chemical formulas for the screening of pharmaco/toxicologically relevant compounds in biological samples using electrospray ionization-time-of-flight mass spectrometry.  

PubMed

Electrospray ionization (ESI)-time-of-flight (TOF) MS enables searching a wide number of pharmaco/toxicologically relevant compounds (PTRC) in biosamples. However, the number of identifiable PTRC depends on extension of reference database of chemical formulas/compound names. Previous approaches proposed in-house or commercial databases with limitations either in PTRC number or content (e.g., few metabolites, presence of non-PTRC). In the frame of development of a ESI-TOF PTRC screening procedure, a subset of PubChem Compound as reference database is proposed. Features of this database (approximately 50,500 compounds) are illustrated, and its performance evaluated through analysis by capillary electrophoresis (CE)-ESI-TOF of hair/blood/urine collected from subjects under treatment with known drugs or by comparison with reference standards. The database is rich in parent compounds of pharmaceutical and illicit drugs, pesticides, and poisons and contains many metabolites (including about 6000 phase I metabolites and 180 glucuronides) and related substances (e.g., impurities, esters). The average number of hits with identical chemical formula is 1.82 +/- 2.27 (median = 1, range 1-39). Minor deficiencies, redundancies, and errors have been detected that do not limit the potential of the database in identifying unknown PTRC. The database allows a much broader search for PTRC than other commercial/in-house databases of chemical formulas/compound names previously proposed. However, the probability that a search retrieves different PTRC having identical chemical formula is higher than with smaller databases, and additional information (anamnestic/circumstantial data, concomitant presence of parent drug and metabolite, selective sample preparation, liquid chromatographic retention, and CE migration behavior) must be used in order to focus the search more tightly. PMID:18336013

Polettini, Aldo; Gottardo, Rossella; Pascali, Jennifer Paola; Tagliaro, Franco

2008-04-15

273

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

274

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

PubMed

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

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

2015-02-01

275

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

276

Using fewer animals to identify chemical eye hazards: revised criteria necessary to maintain equivalent hazard classification.  

PubMed

U.S. Federal Hazardous Substances Act (FHSA) regulations specify eye safety testing procedures and hazard classification criteria for substances regulated by the U.S. Consumer Product Safety Commission (CPSC). Current regulations require up to three sequential 6-animal tests. Testing consistent with the Organisation for Economic Co-operation and Development (OECD) test guideline for eye irritation/corrosion, which specifies 3 animals, can also be submitted to US agencies. However, current FHSA regulations do not provide criteria to classify results from 3-animal tests. An analysis was conducted to determine criteria using results from 3-animal tests that would provide equivalent labeling to FHSA regulations. The frequency that FHSA requirements identify substances as ocular irritants was compared with the frequency that a criterion of either ? 1/3 or ? 2/3 positive animals would identify these substances. A database of rabbit eye tests was also used to estimate over- and underprediction rates for each criterion. In each instance, a criterion of ? 1/3 positive animals more closely matched the expected outcome based on FHSA requirements, while a criterion of ? 2/3 positive animals identified far fewer irritants. Using a classification criterion of ? 1/3 positive animals provided equivalent or greater eye hazard labeling as current FHSA requirements, while using 50-83% fewer animals. PMID:21745525

Haseman, Joseph K; Allen, David G; Lipscomb, Elizabeth A; Truax, James F; Stokes, William S

2011-10-01

277

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

278

A high-resolution genetic map of yellow monkeyflower identifies chemical defense QTLs and recombination rate variation.  

PubMed

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

2014-05-01

279

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

280

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

281

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

282

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

PubMed

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

283

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

284

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

285

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 ...

286

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

287

REDUCTION OF TOXIC AND UNDESIRABLE CHEMICAL COMPOUNDS IN FOOD BY IONIZING IRRADIATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Possible toxic and carcinogenic chemicals such as furan, acrylamide, nitrosamines, biogenic amines, and mycotoxins (aflatoxin B1, patulin, fumonisin, etc.) can accumulate in various foods during thermal processing, preservation and storage. Recent studies have suggested that irradiation reduces leve...

288

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...

289

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

290

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

EPA Science Inventory

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

291

Assignment Kernels For Chemical Compounds Holger Frhlich, Jrg K. Wegner, Andreas Zell  

E-print Network

compounds which is based on the idea of computing optimal assignments between atoms of two different order, length of a bond, etc, and node labels to atom properties, like atom type, partial charge of the marginalized graph kernel. In contrast, the pattern-discovery (PD) kernel by De Raedt and Kramer [11] counts

Zell, Andreas

292

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...

293

Magnolia virginiana Neolignan compounds as chemical barriers to swallowtail butterfly host use.  

PubMed

The role of toxins and deterrents in preventingtroilus group species (Lepidoptera, Papilionidae) from feeding on magnoliaceous hosts was investigated using bioassay-directed isolation ofMagnolia virginiana allelochemicals. A fraction consisting of three neolignan compounds significantly reduced survival of first instarP. palamedes, atroilus group member. Two of these compounds, magnolol and a biphenyl ether, were tested individually and were both toxic toP. palamedes. The larval survival ofP. troilus, anothertroilus group species, was also significantly reduced by magnolol but not by the biphenyl ether. In contrast,P. glaucus, a polyphagousglaucus group species that feeds on magnoliaceous hosts, was not affected by either compound. The effect of these compounds against a. polyphagous nonpapilionid was examined using the fall webworm (Hyphantria cunea, Lepidoptera: Arctiidae). The biphenyl ether but not magnolol significantly lowered webworm first-instar survival, demonstrating that polyphagy does not preadapt lepidopterans to feeding on this neolignan. These results demonstrate that although phagostimulants play a role in the specialization of thetroilus group on the Lauraceae, the presence of toxins and/or deterrents in nonhosts is also important in determining food plant patterns in these species. PMID:24254295

Nitao, J K; Johnson, K S; Scriber, J M; Nair, M G

1992-09-01

294

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...

295

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

EPA Science Inventory

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

296

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

ERIC Educational Resources Information Center

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

Gonzalez, Gabriel; Seco, Miquel

2004-01-01

297

Multipurpose indicator in cells using intramolecular FRET between GFP and chemical compounds  

NASA Astrophysics Data System (ADS)

Specific, surface cysteine sites have been introduced into Green Fluorescent Protein (GFP) to allow site-specific chemical modification by thiol-directed reagents. These sites have been labelled using BODIPY/eosin/rhodamine reagents as chemical FRET partners for the native GFP chromophore. When they were excited at 488 nm these engineered GFP: conjugated-fluorophore constructs, showed quenching of the native GFP fluorophore emission at 511 nm. New emission bands appeared correponding to each chemical fluorophore emission. Thus the new GFP chimeras exhibited strong intramolecular FRET. GFP mutants were then engineered with trypsin-sensitive sequences located close to the chemical fluorophore-bearing cysteine site. Trypsinolysis caused major changes in the FRET fluorescence spectra. On trypsinolysis the FRET was destroyed, as the FRET partners were now on separate molecules in the cleaved products. T Consequently, the emission wavelength altered from that of the chemically conjugated FRET partner back to that of the native fluorophore of the GFP (511 nm). This provides the possibility of efficient, ratio-based detection. Thus, protein re-engineering has led to novel probes capable of enzymatic triggering based on intramolecular FRET between GFP and specifically sited chemical labels.

Suzuki, Miho; Ito, Yoichiro; Savage, Hannah E.; Husimi, Yuzuru; Douglas, Kenneth T.

2003-07-01

298

A novel energy-efficient plasma chemical process for the destruction of volatile toxic compounds. 1997 annual progress report  

SciTech Connect

'The objective of this research program is to develop new plasma chemical processes for the destruction of volatile toxic compounds (VTCs) in contaminated air streams where the contamination levels are below a few percent. The authors plan to exploit the large cross sections associated with dissociative electron attachment to highly excited molecular states. Such highly excited states are to be populated in glow discharges via excitation transfer from high- lying, metastable states of rare gases. Basic knowledge of the excitation transfer processes and the electron attachment processes are crucial to the development of the proposed techniques, and these processes will be studied in detail.'

Pinnaduwage, L.A.; Ma, C.Y.L.

1997-09-01

299

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

300

Characterization of Pellicle Inhibition in Gluconacetobacter xylinus 53582 by a Small Molecule, Pellicin, Identified by a Chemical Genetics Screen  

Microsoft Academic Search

Pellicin ([2E]-3-phenyl-1-[2,3,4,5-tetrahydro-1,6-benzodioxocin-8-yl]prop-2-en-1-one) was identified in a chemical genetics screen of 10,000 small molecules for its ability to completely abolish pellicle production in Gluconacetobacter xylinus. Cells grown in the presence of pellicin grew 1.5 times faster than untreated cells. Interestingly, growth in pellicin also caused G. xylinus cells to elongate. Measurement of cellulose synthesis in vitro showed that cellulose synthase activity

Janice L. Strap; Andrew Latos; Isaac Shim; Dario T. Bonetta

2011-01-01

301

An In vivo Chemical Genetic Screen Identifies Phosphodiesterase 4 as a Pharmacological Target for Hedgehog signaling Inhibition  

PubMed Central

SUMMARY Hedgehog (Hh) signaling plays an integral role in vertebrate development, and its dysregulation has been widely accepted as a driver of numerous malignancies. While a variety of small molecules target Smoothened (Smo) as a strategy for Hh inhibition, Smo gain of function mutations have limited their clinical implementation. Modulation of targets downstream of Smo could define a paradigm for treatment of Hh-dependent cancers. Here, we describe eggmanone, a small molecule identified from a chemical genetic zebrafish screen which induced a Hh-null phenotype. Eggmanone exerts its Hh-inhibitory effects through selective antagonism of phosphodiesterase (PDE) 4, leading to protein kinase A activation and subsequent Hh blockade. Our study implicates PDE4 as a target for Hh inhibition, suggests an improved strategy for Hh-dependent cancer therapy and identifies a unique probe of downstream-of-Smo Hh modulation. PMID:25818300

Williams, Charles H.; Hempel, Jonathan E.; Hao, Jijun; Frist, Audrey Y.; Williams, Michelle M.; Fleming, Jonathan T.; Sulikowski, Gary A.; Cooper, Michael K.; Chiang, Chin; Hong, Charles C.

2015-01-01

302

Chemical composition and phenolic compound profile of mortiño (Vaccinium floribundum Kunth).  

PubMed

The phenolic compounds in mortiño (Vaccinium floribundum Kunth, family Ericaceae) from the páramos of Ecuador were studied by LC-DAD-MS/MS for the first time. (-)-Epicatechin, one dimer A and one trimer A were found at a total concentration of 18 mg/100 g FW. Of the flavonol glycosides (38 mg/100 g FW), quercetin and myricetin were found as -3-O-hexosides, -3-O-pentosides and -3-O-deoxyhexosides. Chlorogenic and neochlorogenic acids together with caffeic/ferulic acid derivatives were found as predominant components among the hydroxycinnamic acids in the berry. Anthocyanins, including cyanidin and delphinidin derivatives, were the major phenolic compound class quantified (345 mg cyanidin-3-O-glucoside/100 g FW). PMID:19719139

Vasco, Catalina; Riihinen, Kaisu; Ruales, Jenny; Kamal-Eldin, Afaf

2009-09-23

303

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

304

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

PubMed Central

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

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

2015-01-01

305

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

PubMed

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

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

2015-01-01

306

RESPONSE OF PORTABLE VOC (VOLATILE ORGANIC COMPOUNDS) ANALYZERS TO CHEMICAL MIXTURES  

EPA Science Inventory

The report gives the responses of two types of portable VOC analyzers (Century Systems OVA-108 and Bacharach TLV Sniffer), calibrated with methane and used to measure a variety of chemical vapor mixtures. Instrument response data for both binary and ternary mixtures of selected c...

307

Cell-Based Chemical Genetic Screen Identifies Damnacanthal as an Inhibitor of HIV-1 Vpr Induced Cell Death  

PubMed Central

Viral protein R (Vpr), one of the human immunodeficiency virus type 1 (HIV-1) accessory proteins, contributes to multiple cytopathic effects, G2 cell cycle arrest and apoptosis. The mechanisms of Vpr have been intensely studied because it is believed that they underlie HIV-1 pathogenesis. We here report a cell-based small molecule screen on Vpr induced cell death in the context of HIV-1 infection. From the screen of 504 bioactive compounds, we identified Damnacanthal (Dam), a component of noni fruit, as an inhibitor of Vpr induced cell death. Our studies illustrate a novel efficient platform for drug discovery and development in anti-HIV therapy which should also be applicable to other viruses. PMID:16904642

Kamata, Masakazu; Wu, Raymond P.; An, Dong Sung; Saxe, Jonathan P.; Damoiseaux, Robert; Phelps, Michael E.; Huang, Jing; Chen, Irvin S.Y.

2006-01-01

308

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

PubMed

Viral protein R (Vpr), one of the human immunodeficiency virus type 1 (HIV-1) accessory proteins, contributes to multiple cytopathic effects, G2 cell cycle arrest and apoptosis. The mechanisms of Vpr have been intensely studied because it is believed that they underlie HIV-1 pathogenesis. We here report a cell-based small molecule screen on Vpr induced cell death in the context of HIV-1 infection. From the screen of 504 bioactive compounds, we identified damnacanthal (Dam), a component of noni [corrected] as an inhibitor of Vpr induced cell death. Our studies illustrate a novel efficient platform for drug discovery and development in anti-HIV therapy which should also be applicable to other viruses. PMID:16904642

Kamata, Masakazu; Wu, Raymond P; An, Dong Sung; Saxe, Jonathan P; Damoiseaux, Robert; Phelps, Michael E; Huang, Jing; Chen, Irvin S Y

2006-09-29

309

Annual fluxes of particulate chemical trace compounds during the North-East water polynya experiment  

NASA Astrophysics Data System (ADS)

Particulate fluxes of organic marker substances (alkanes, wax esters, pristane, and alkenones) and trace elements (Al, Cd, Cu, Fe, Mn, Ni, and Pb) were determined from identical samples of sediment trap material collected at North East Water Polynya (NEWP) locations E and F in the north-western Greenland Sea. Samples from the East Greenland Shelf were obtained with two sediment traps deployed at 130 m depth over a 331-day period from August 1992 to June 1993 within the NEWP experiment. Particulate fluxes of the chemical tracers showed a pronounced seasonality, which was largely consistent with ice-coverage data. Relative flux pattern exhibited initial maxima during August and September 1992. Fluxes were lowest during winter time (November 1992 to early March 1993), followed by an increase by a factor of 2-5 in mid-March 1993. In contrast, flux of n-alkanes occurred almost entirely in spring 1993. Flux of alkenones was not detectable throughout this experiment. Temporal variations of chemical tracer fluxes at trap location E were similar to those of station F during autumn 1992. Normalization calculations showed that lithogenic material was an important source for trace element fluxes, with an estimated lithogenic fraction of the bulk material flux increasing from autumn to spring. A non-lithogenic flux component was observed for Cd throughout the time of deployment. The chemical data indicate that during the peak flux periods a large proportion of the sinking particles consisted of fresh material. Differences in the patterns of the bulk material flux and the chemical tracer fluxes indicate that there must have been a substantial difference between autumn and spring in the gross chemical composition of the sinking material.

Schü?ler, Uwe; Schulz-Bull, Detlef E.; Bauerfeind, Eduard

1997-01-01

310

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

311

Chemical shifts of K-X-ray absorption edges on copper in different compounds by X-ray absorption spectroscopy (XAS) with Synchrotron radiation  

NASA Astrophysics Data System (ADS)

Cu K X-ray absorption edges were measured in compounds such as CuO, Cu(CH3CO2)2, Cu(CO3)2, and CuSO4 where Cu is present in oxidation state of 2+, using the energy dispersive EXAFS beamline at INDUS-2 Synchrotron radiation source at RRCAT, Indore. Energy shifts of ˜4-7 eV were observed for Cu K X-ray absorption edge in the above compounds compared to its value in elemental copper. The difference in the Cu K edge energy shifts in the different compounds having same oxidation state of Cu shows the effect of different chemical environments surrounding the cation in the above compounds. The above chemical effect has been quantitatively described by determining the effective charges on Cu cations in the above compounds.

Joseph, D.; Basu, S.; Jha, S. N.; Bhattacharyya, D.

2012-03-01

312

Chemical differentiation of volatile compounds in crude and processed Atractylodis Macrocephalae Rhizoma by using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry combined with multivariate data analysis.  

PubMed

In the present study, comprehensive 2D GC-TOF-MS combined with multivariate data analysis was applied to analyze the differences of the volatile components in crude and processed Atractylodis Macrocephalae Rhizoma (AMR) samples. As a result, 26 compounds that were found in crude AMR samples disappeared in processed AMR samples, and 19 compounds were newly generated and identified in AMR after processing with wheat bran. Meanwhile, principal component analysis demonstrated that there were significant chemical differences between crude and processed AMR samples, and processing procedure caused obvious quantitative and qualitative changes of volatile components in AMR. The established method could be used to explain the chemical differentiation between crude and processed AMR, and to further understand the processing mechanism of herbal medicines. PMID:24596078

Cao, Gang; Cai, Hao; Jiang, Jianping; Yao, Linjiang; Tu, Sicong; Wang, Lin; Ma, Xiaoqing; Cai, Baochang

2014-05-01

313

Hiding in plain sight: cuticular compound profile matching conceals a larval tortoise beetle in its host chemical cloud.  

PubMed

Larvae of tortoise beetles are postulated to have fecal shields as the main defensive strategy against predators. Such a device protects beetles both physically and chemically. In order to examine how larvae Chelymorpha reimoseri are protected against predatory ants, which frequently visit extrafloral nectaries in their host plant, the morning glory Ipomoea carnea, we conducted anti-predation bioassays with live 5th instars. In the field, larvae in contact with ants had survival between 40 and 73 %, independently of shield presence. In the laboratory, when exposed to Camponotus crassus, larvae with shields had significantly higher survival (85 %) than those without shields (64 %). In both scenarios, larval survival was significantly higher when compared with palatable Spodoptera frugiperda larvae, as the latter were all consumed. We also observed that when C. reimoseri larvae showed no movement, the ants walked on them without attacking. We hypothesized that if the larval integument has a pattern of cuticular compounds (CCs) similar to that of its host plant, larvae would be rendered chemically camouflaged. In the field and laboratory, the freeze-dried palatable larvae of S. frugiperda treated with CCs of 5th instar C. reimoseri and left on I. carnea leaves were significantly less removed by ants than controls without these compounds. We also found a similarity of approximately 50 % between the CCs in C. reimoseri larvae and I. carnea host leaves. Both findings provide evidence in support of the hypothesis that chemical camouflage plays an important role in larval defense, which is reported for the first time in an ectophagous leaf beetle larva. PMID:24744044

Massuda, Kamila Ferreira; Trigo, José Roberto

2014-04-01

314

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

315

Pharmacophore modeling and molecular dynamics simulation to identify the critical chemical features against human sirtuin 2 inhibitors  

NASA Astrophysics Data System (ADS)

Sirtuin 2 (SIRT2) is one of the emerging targets in chemotherapy field and mainly associated with many diseases such as cancer and Parkinson's. Hence, quantitative hypothesis was developed using Discovery Studio v2.5. Top ten resultant hypotheses were generated, among them Hypo1 was selected as a best hypothesis based on the statistical parameters like high cost difference (52), lowest RMS (0.71), and good correlation coefficient (0.96). Hypo1 has been validated by using well known methodologies such as Fischer's randomization method (95% confidence level), test set which has shown the correlation coefficient of 0.93 as well as the goodness of hit (0.65), and enrichment factor (8.80). All the above statistical validations confirm that the chemical features in Hypo1 (1 hydrogen bond acceptor, 1 hydrophobic, and 2 ring aromatic features) was able to inhibit the function of SIRT2. Hence, Hypo1 was used as a query in virtual screening to find a novel scaffolds by screening the various chemical databases. The screened molecules from the databases were checked for the ADMET as well as the drug-like properties. Due to the lack of SIRT2-ligand complex structure in PDB, molecular docking and molecular dynamics (MD) simulation was carried out to find the suitable orientation of ligand in the active site. The representative structure from MD simulations was used as a receptor to dock the molecules which passed the drug-like properties from the virtual screening. Finally, 29 compounds were selected as a potent candidate leads based on the interactions with the active site residues of SIRT2. Thus, the resultant pharmacophore can be used to discover and design the SIRT2 inhibitors with desired biological activity.

Sakkiah, Sugunadevi; Baek, Ayoung; Lee, Keun Woo

2012-03-01

316

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

317

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

PubMed Central

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 IQ) 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 IQ. By employing CN-POBS in mitochondria respiring on NADH-generating substrates, we show that site IQ 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 in both normal and pathological conditions. PMID:23994103

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

2013-01-01

318

A wireless hybrid chemical sensor for detection of environmental volatile organic compounds  

PubMed Central

A hybrid sensor for monitoring volatile organic compounds (VOCs) in air is developed. The device combines two orthogonal sensing principles, selective molecular binding with a microfabricated quartz tuning fork detector and separation of analytes with a column. The tuning fork detector is functionalized with molecular imprinted polymers for selective binding to benzene, toluene, ethylbenzene, and xylenes (BTEX), and the separation column provides further discrimination of the analytes for real world complex sample analysis. The device is wireless, portable, battery-powered, and cell-phone operated, and it allows reliable detection in parts per billion (ppb) by volume-levels of BTEX in the presence of complex interferents. The hybrid device is suitable for occupational, environmental health, and epidemiological applications. PMID:24078793

Chen, Cheng; Tsow, Francis; Campbell, Katherine Driggs; Iglesias, Rodrigo; Forzani, Erica; Tao, N.J.

2013-01-01

319

Lysergic acid diethylamide antagonizes shaking induced in rats by five chemically different compounds  

Microsoft Academic Search

Thyrotropin-releasing hormone (TRH), sodium valproate, AG-3-5 (1-[2-hydroxyphenyl]-4-[3-nitrophenyl]-1,2,3,6-tetrahydropyrimidine-2-one), RX336-M (7,8-dihydro-5', 6'-dimethylcyclohex-5'-eno-1',2',8',14 codeinone), and Sgd 8473 (a-[(4-chlorobenzylideneamino)-oxy]-isobutyric acid) each induced repetitive shaking of the body of rats after intraperitoneal injection. This action of the five diverse chemicals appears to be subserved by a common pharmacological component, because pretreatment with d-lysergic acid diethylamide (0.03–1.0 mg kg-1, s.c.) attenuated the shaking behavior in a

Alan Cowan; Trevor Watson

1978-01-01

320

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

321

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

322

Adenosine Kinase of T. b. rhodesiense Identified as the Putative Target of 4-[5-(4-phenoxyphenyl)-2H-pyrazol-3-yl]morpholine Using Chemical Proteomics  

PubMed Central

Background Human African trypanosomiasis (HAT), a major parasitic disease spread in Africa, urgently needs novel targets and new efficacious chemotherapeutic agents. Recently, we discovered that 4-[5-(4-phenoxyphenyl)-2H-pyrazol-3-yl]morpholine (compound 1) exhibits specific antitrypanosomal activity with an IC50 of 1.0 µM on Trypanosoma brucei rhodesiense (T. b. rhodesiense), the causative agent of the acute form of HAT. Methodology/Principal Findings In this work we show adenosine kinase of T. b. rhodesiense (TbrAK), a key enzyme of the parasite purine salvage pathway which is vital for parasite survival, to be the putative intracellular target of compound 1 using a chemical proteomics approach. This finding was confirmed by RNA interference experiments showing that down-regulation of adenosine kinase counteracts compound 1 activity. Further chemical validation demonstrated that compound 1 interacts specifically and tightly with TbrAK with nanomolar affinity, and in vitro activity measurements showed that compound 1 is an enhancer of TbrAK activity. The subsequent kinetic analysis provided strong evidence that the observed hyperactivation of TbrAK is due to the abolishment of the intrinsic substrate-inhibition. Conclusions/Significance The results suggest that TbrAK is the putative target of this compound, and that hyperactivation of TbrAK may represent a novel therapeutic strategy for the development of trypanocides. PMID:19707572

Kuettel, Sabine; Mosimann, Marc; Mäser, Pascal; Kaiser, Marcel; Brun, Reto; Scapozza, Leonardo; Perozzo, Remo

2009-01-01

323

Metabolic footprinting: a new approach to identify physiological changes in complex microbial communities upon exposure to toxic chemicals.  

PubMed

Metabolic footprinting coupled with statistical analysis was applied to multiple, chemically stressed activated sludge cultures to identify probable biomarkers that indicate community stress. The impact of cadmium (Cd), 2,4-dinitrophenol (DNP), and N-ethyl-maleimide (NEM) shock loads on the composition of the soluble fraction of activated sludge cultures was analyzed by gross biomolecular analyses and liquid chromatography-mass spectrometry (LC-MS). Fresh mixed liquor from four distinct treatment plants was each divided in four different batches and was subjected to no chemical addition (control) and spike additions of the stressors Cd, DNP, or NEM. The results indicate that chemical stress caused a significant release of proteins, carbohydrates, and humic acids from the floc structure into the bulk liquid. Using discriminant function analysis (DFA) with genetic algorithm variable selection (GA-DFA), the samples subjected to the different stress conditions plus control could be differentiated, thereby indicating that the footprints of the soluble phase generated by LC-MS were different for the four conditions tested and, therefore, were toxin-specific but community-independent. These footprints, thus, contain information about specific biomolecular differences between the stressed samples, and we found that only a limited number of m/z (mass to charge) ratios from the mass spectra were needed to differentiate between the control and each stressed sample. Since the experiments were conducted with mixed liquor from four distinct wastewater treatment plants, the discriminant m/z ratios may potentially be used as universal stress biomarkers in activated sludge systems. PMID:17612173

Henriques, Inês D S; Aga, Diana S; Mendes, Pedro; O'Connor, Seamus K; Love, Nancy G

2007-06-01

324

Use of medaka (Oryzias latipes) as a model teleost to identify reproductive endpoints indicative of exposure to endocrine disrupting chemicals  

SciTech Connect

The purpose of this research is to identify effects of endocrine disrupting chemicals on the reproductive system of fish at various stages of sexual differentiation and development. The model teleost used was the d-rR strain of medaka (Oryzias latipes) which has a heritable sex-linked color gene. In medaka, sex differences are first detected at the cellular level at hatch. In males, the mitotic activity of the primordial germ cells (PGC) is arrested while the PGCs of the females continue to divide. The germ cells of the gonochoristic medaka have been demonstrated to be totipotent with respective to gonia production. Because endogenous sex steroid hormones are believed to regulate this early process of sexual differentiation, the authors have hypothesized that mitotic activity in males and females exposed to endocrine disrupting chemicals will be different than unexposed individuals. Results are presented for tests conducted by injecting medaka eggs within 36 hours post-hatch with 3 doses of 2,3,7,8-TCDD (nominally 2.3, 1.3, 0.2 pg/embryo), a known anti-estrogen, dissolved in triolein.

Papoulias, D.M.; Tillitt, D.; Jones, S. [National Biological Service, Columbia, MO (United States); Noltie, D. [Univ. of Missouri, Columbia, MO (United States)

1995-12-31

325

Efficacy of some oils and chemical compounds on Insignorthezia insignis (Browne) (Hemiptera: Ortheziidae) infesting Lantana camara in Alexandria, Egypt.  

PubMed

Field and laboratory experiments were conducted in March, 2008 in El-Nouzha garden, Alexandria governorate. Pre-and post treatment inspections of the insects were examined and recorded before and after (2,4,8, and 12 weeks). Spraying was applied to evaluate the efficiency of the tested compounds, [Mineral oils (KZ oil and Star oil); IGRs (Chlorfluazuron, lufenuron and pyriproxyfen); Neem oil; emamectin benzoate and thiamethoxam]. Percentages of reduction were calculated. The ensign scale insects Insignorthezia insignis (Browne) were collected from treated Lantana camara shrubs to investigate the effect of the tested chemicals on Aspartate transferase (AST), Alanine transferase (ALT) and Alkaline-phosphatase (ALPK) of the insect enzymes activities. From the obtained results, it could be concluded that the tested materials gave good results for controlling both adult and immature stages of the ensign scale insect Insignorthezia insignis (Browne) that infested Lantana camara shrubs, through affecting enzymes activities of the assigned insect pest. PMID:21539253

Moursi, S Khadiga; Abo-Shanab, A S H; Mesbah, H A; Abdel-Razak, S I; Mourad, A K; Zaghloul, O A; Abdel-Fatah, R S

2010-01-01

326

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

327

Chemical Biology Chemical Screening for Hair Cell Loss and Protection  

E-print Network

Chemical Biology Chemical Screening for Hair Cell Loss and Protection in the Zebrafish Lateral Line Rubel,1,2 and David W. Raible1,4 Abstract In humans, most hearing loss results from death of hair cells of mechanosensory hair cells. We discuss chemical screens to identify compounds that induce hair cell loss

Rubel, Edwin

328

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

329

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

NASA Astrophysics Data System (ADS)

This study describes the design, assembly, testing and comparison of two Remote Raman Spectroscopy (RRS) systems intended for standoff detection of hazardous chemical liquids. Raman spectra of Chemical Warfare Agents Simulants (CWAS) and Toxic Industrial Compounds (TIC) were measured in the laboratory at a 6.6 m source-target distance using continuous wave (CW) laser detection. Standoff distances for pulsed measurements were 35 m for dimethyl methylphosphonate (DMMP) detection and 60, 90 and 140 m for cyclohexane detection. The prototype systems consisted of a Raman spectrometer equipped with a CCD detector (for CW measurements) and an I-CCD camera with time-gated electronics (for pulsed laser measurements), a reflecting telescope, a fiber optic assembly, a single-line CW laser source (514.5, 488.0, 351.1 and 363.8 nm) and a frequency-doubled single frequency Nd:YAG 532 nm laser (5 ns pulses at 10 Hz). The telescope was coupled to the spectrograph using an optical fiber, and filters were used to reject laser radiation and Rayleigh scattering. Two quartz convex lenses were used to collimate the light from the telescope from which the telescope-focusing eyepiece was removed, and direct it to the fiber optic assembly. To test the standoff sensing system, the Raman Telescope was used in the detection of liquid TIC: benzene, chlorobenzene, toluene, carbon tetrachloride, cyclohexane and carbon disulfide. Other compounds studied were CWAS: dimethylmethyl phosphonate, 2-chloroethyl ethyl sulfide and 2-(butylamino)-ethanethiol. Relative Raman scattering cross sections of liquid CWAS were measured using single-line sources at 532.0, 488.0, 363.8 and 351.1 nm. Samples were placed in glass and quartz vials at the standoff distances from the telescope for the Remote Raman measurements. The mass of DMMP present in water solutions was also quantified as part of the system performance tests.

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

2010-09-01

330

Rapid characterization of chemical compounds in liquid and solid states using thermal desorption electrospray ionization mass spectrometry.  

PubMed

Rapid characterization of thermally stable chemical compounds in solid or liquid states is achieved through thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS). A feature of this technique is that sampling, desorption, ionization, and mass spectrometric detection are four separate events with respect to time and location. A metal probe was used to sample analytes in their solid or liquid states. The probe was then inserted in a preheated oven to thermally desorb the analytes on the probe. The desorbed analytes were carried by a nitrogen gas stream into an ESI plume, where analyte ions were formed via interactions with charged solvent species generated in the ESI plume. The analyte ions were subsequently detected by a mass analyzer attached to the TD-ESI source. Quantification of acetaminophen in aqueous solutions using TD-ESI/MS was also performed in which a linear response for acetaminophen was obtained between 25 and 500 ppb (R(2) = 0.9978). The standard deviation for a reproducibility test for ten liquid samples was 9.6%. Since sample preparation for TD-ESI/MS is unnecessary, a typical analysis can be completed in less than 10 s. Analytes such as the active ingredients in over-the-counter drugs were rapidly characterized regardless of the different physical properties of said drugs, which included liquid eye drops, viscous cold syrup solution, ointment cream, and a drug tablet. This approach was also used to detect trace chemical compounds in illicit drugs and explosives, in which samples were obtained from the surfaces of a cell phone, piece of luggage made from hard plastic, business card, and wooden desk. PMID:24050317

Huang, Min-Zong; Zhou, Chi-Chang; Liu, De-Lin; Jhang, Siou-Sian; Cheng, Sy-Chyi; Shiea, Jentaie

2013-10-01

331

Molecular stopping powers and effect of chemical bonding in gaseous amine compounds  

NASA Astrophysics Data System (ADS)

Molecular stopping powers of methylamine, ethylamine, dimethylamine, and trimethylamine have been measured for 0.3-2.0 MeV He+ ions. A single-bonded atomic stopping power ?SB(N) for nitrogen is calculated and found to be 6%-20% lower than its triple-bonded counterpart (1/2)?expt(N2). This disagreement is quite similar to a 6%-17% difference in single- and double-bonded carbon and oxygen atomic stopping powers previously calculated. A lower stopping power peak energy is also observed for the atom in a molecular configuration of higher bond order. These trends demonstrate clearly the effect of chemical bonding upon stopping powers.

Powers, D.; Olson, H. G.; Gowda, R.

1984-03-01

332

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

333

Spin forbidden chemical reactions of transition metal compounds. New ideas and new computational challenges.  

PubMed

Many reactions of transition metal compounds involve a change in spin. These reactions may proceed faster, slower--or at the same rate as--otherwise equivalent processes in which spin is conserved. For example, ligand substitution in [CpMo(Cl)2(PR3)2] is faster than expected, whereas addition of dinitrogen to [Cp*Mo(Cl)(PMe3)2] is slow. Spin-forbidden oxidative addition of ethylene to [Cp*Ir(PMe3)] occurs competitively with ligand association. To explain these observations, we discuss the shape of the different potential energy surfaces (PESs) involved, and the energy of the minimum energy crossing points (MECPs) between them. This computational approach is of great help in understanding the mechanisms of spin-forbidden reactions, provided that accurate calculations can be used to predict the relevant PESs. Density functional theory, especially using gradient-corrected and hybrid functionals, performs reasonably well for the difficult problem of predicting the energy splitting between different spin states of transition metal complexes, although careful calibration is needed. PMID:12596540

Poli, Rinaldo; Harvey, Jeremy N

2003-01-01

334

Effect of adding Lactobacillus plantarum and soluble carbohydrates to swine manure on odorous compounds, chemical composition and indigenous flora.  

PubMed

Manure odor, which results in the increasing complaints and lawsuits, has increased the tension among swine producers and surrounding residents. The effects of Lactobacillus plantarum and different rates of soluble carbohydrates additions to swine manure on odorous compounds, chemical compounds and indigenous flora were evaluated. Additions were calculated on dried manure weight basis. Variables monitored included ammonia (NH3), hydrogen sulfide (H2S), odor offensiveness, pH, ammonium nitrogen (NH4(+)-N), volatile fatty acids (VFAs), urease and indigenous flora. The results indicated that the combination of L. plantarum and soluble carbohydrates dramatically reduced manure pH. Lower pH resulted in the reduction of NH3 volatilization (34.6%-92.4%, P < 0.01), the increases of H2S (P < 0.05) and NH4(+)-N (5.3%-17.5%, P < 0.05). In addition, L. plantarum and soluble carbohydrates additions significantly reduced odor offensiveness, those VFAs related to malodor indicators (valeric acids, 12.3%-47.7%, P < 0.05; iso-valeric, 3.5%-23.8%) and the main microorganisms responsible for odor production, with the number of Eubacteria in swine manure reducing by 4.9%, 11.6%, 17.4%, 34.1% and 32.2% respectively. PMID:20050573

Huang, Can; Li, Ji; Kang, Wen-Li; Tang, Xin-Yan

2006-01-01

335

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

336

40 CFR 721.9668 - Organotin lithium compound.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Organotin lithium compound. 721.9668 Section 721...Substances § 721.9668 Organotin lithium compound. (a) Chemical substance...generically identified as an organotin lithium compound (PMN P-93-1119) is...

2014-07-01

337

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

338

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

339

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

340

Fun with Compound Words  

NSDL National Science Digital Library

Identify and create compound words We will be studying compound words! First we need to find out what a compound word is, go to this website and read about compound words.What is a compound word Now that you have read about compound words lets do some fun activities to help us review. First go to Compound word flashcards, here you will ...

Ms. Huggins

2012-04-12

341

The application of discriminant analysis and Machine Learning methods as tools to identify and classify compounds with potential as transdermal enhancers.  

PubMed

Discriminant analysis (DA) has previously been shown to allow the proposal of simple guidelines for the classification of 73 chemical enhancers of percutaneous absorption. Pugh et al. employed DA to classify such enhancers into simple categories, based on the physicochemical properties of the enhancer molecules (Pugh et al., 2005). While this approach provided a reasonable accuracy of classification it was unable to provide a consistently reliable estimate of enhancement ratio (ER, defined as the amount of hydrocortisone transferred after 24h, relative to control). Machine Learning methods, including Gaussian process (GP) regression, have recently been employed in the prediction of percutaneous absorption of exogenous chemicals (Moss et al., 2009; Lam et al., 2010; Sun et al., 2011). They have shown that they provide more accurate predictions of these phenomena. In this study several Machine Learning methods, including the K-nearest-neighbour (KNN) regression, single layer networks, radial basis function networks and the SVM classifier were applied to an enhancer dataset reported previously. The SMOTE sampling method was used to oversample chemical compounds with ER>10 in each training set in order to improve estimation of GP and KNN. Results show that models using five physicochemical descriptors exhibit better performance than those with three features. The best classification result was obtained by using the SVM method without dealing with imbalanced data. Following over-sampling, GP gives the best result. It correctly assigned 8 of the 12 "good" (ER>10) enhancers and 56 of the 59 "poor" enhancers (ER<10). Overall success rates were similar. However, the pharmaceutical advantages of the Machine Learning methods are that they can provide more accurate classification of enhancer type with fewer false-positive results and that, unlike discriminant analysis, they are able to make predictions of enhancer ability. PMID:22101136

Moss, G P; Shah, A J; Adams, R G; Davey, N; Wilkinson, S C; Pugh, W J; Sun, Y

2012-01-23

342

ADAPTATION OF NATURAL MICROBIAL MMUNITIES TO DEGRADATION OF XENOBIOTIC COMPOUNDS: EFFECTS OF CONCENTRATION, EXPOSURE TIME, INOCULUM, AND CHEMICAL STRUCTURE  

EPA Science Inventory

Adaptation of microbial populations to degrade xenobiotic compounds faster after exposure to the compound was studied in eco-cores. Radiolabeled test compounds were added to cores that contained natural water and sediment samples. Adaptation was detected by comparing mineralizati...

343

Distribution of volatile organic compounds (VOCs) in surface water, soil, and groundwater within a chemical industry park in Eastern China.  

PubMed

This paper focuses on the distribution of volatile organic compounds (VOCs) in the surface water, soil, and groundwater within a chemical industry park in Eastern China. At least one VOC was detected in each of the 20 sampling sites, and the maximum number of VOCs detected in the surface water, groundwater, and soil were 13, 16, and 14, respectively. Two of the 10 VOCs with elevated concentrations detected in surface water, groundwater, and soil were chloroform and 1,2-dichloroethane. The characteristics of VOCs, which include volatility, boiling point, and solubility, could significantly affect their distribution in surface water, soil, and groundwater. However, due to the direct discharging of chemical industry wastewater into surface water, higher concentrations of VOCs (except chloroform) were detected in surface water than in soil and groundwater. Fortunately, the higher volatility of VOCs prevents the VOCs from impacting groundwater, which helps to maintain a lower concentration of VOCs in the groundwater than in both surface water and soil. This is because pollutants with relatively higher boiling points and lower solubilities have higher detection frequencies in soil, and contaminants with relatively lower boiling points and higher solubilities have higher detection frequencies in water, notably in surface water. PMID:25633950

Liu, Benhua; Chen, Liang; Huang, Linxian; Wang, Yongseng; Li, Yuehua

2015-01-01

344

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

345

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

Saïdani, Nadia; Botté, Cyrille Y.; Deligny, Michael; Bonneau, Anne-Laure; Reader, Janette; Lasselin, Ronald; Merer, Goulven; Niepceron, Alisson; Brossier, Fabien; Cintrat, Jean-Christophe; Rousseau, Bernard; Birkholtz, Lyn-Marie; Cesbron-Delauw, Marie-France; Dubremetz, Jean-François; Mercier, Corinne; Vial, Henri; Lopez, Roman

2014-01-01

346

Data analysis of multi-laser standoff spectral identification of chemical and biological compounds  

NASA Astrophysics Data System (ADS)

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 development 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.; Zaharov, V.; Tetard, L.; Thundat, T.; Passian, A.

2013-06-01

347

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

348

Screening of an FDA-Approved Compound Library Identifies Four Small-Molecule Inhibitors of Middle East Respiratory Syndrome Coronavirus Replication in Cell Culture  

PubMed Central

Coronaviruses can cause respiratory and enteric disease in a wide variety of human and animal hosts. The 2003 outbreak of severe acute respiratory syndrome (SARS) first demonstrated the potentially lethal consequences of zoonotic coronavirus infections in humans. In 2012, a similar previously unknown coronavirus emerged, Middle East respiratory syndrome coronavirus (MERS-CoV), thus far causing over 650 laboratory-confirmed infections, with an unexplained steep rise in the number of cases being recorded over recent months. The human MERS fatality rate of ?30% is alarmingly high, even though many deaths were associated with underlying medical conditions. Registered therapeutics for the treatment of coronavirus infections are not available. Moreover, the pace of drug development and registration for human use is generally incompatible with strategies to combat emerging infectious diseases. Therefore, we have screened a library of 348 FDA-approved drugs for anti-MERS-CoV activity in cell culture. If such compounds proved sufficiently potent, their efficacy might be directly assessed in MERS patients. We identified four compounds (chloroquine, chlorpromazine, loperamide, and lopinavir) inhibiting MERS-CoV replication in the low-micromolar range (50% effective concentrations [EC50s], 3 to 8 ?M). Moreover, these compounds also inhibit the replication of SARS coronavirus and human coronavirus 229E. Although their protective activity (alone or in combination) remains to be assessed in animal models, our findings may offer a starting point for treatment of patients infected with zoonotic coronaviruses like MERS-CoV. Although they may not necessarily reduce viral replication to very low levels, a moderate viral load reduction may create a window during which to mount a protective immune response. PMID:24841269

de Wilde, Adriaan H.; Jochmans, Dirk; Posthuma, Clara C.; Zevenhoven-Dobbe, Jessika C.; van Nieuwkoop, Stefan; Bestebroer, Theo M.; van den Hoogen, Bernadette G.

2014-01-01

349

Chemical composition, biological and cytotoxic activities of plant extracts and compounds isolated from Ferula lutea.  

PubMed

The present work describes the phytochemical study on Ferula lutea flowers. Total phenolics and flavonoids of the n-butanol and ethyl acetate extracts were quantified (phenolics [40.68-52.29 mg gallic acid equivalent/g of dry weight], flavonoids [12.38-14.72 mg quercitin/g dry weight]). Two diastereoisomers were isolated and identified using spectroscopic techniques (1D, 2D NMR and GC-MS). The extracts and diastereoisomers were tested for antioxidant, antiacetylcholinesterase, antimicrobial, antidiabectic, cytotoxic (leukemia cell line) activities and allelopathic potentialities. The strongest antioxidant activity was obtained for the ethyl acetate extract (IC?? = 12.8 ± 1.29 µg/mL). The two extracts exhibited high antidiabetic activity (54.1 and 52.1% at 40 µg/mL). PMID:24577376

Znati, Mansour; Hichem, Ben Jannet; Cazaux, Sylvie; Bouajila, Jalloul

2014-01-01

350

Predominant chemicals in Hanford site waste tanks  

Microsoft Academic Search

Predominant chemical constituents in Hanford Site single-shell and double-shell tanks are determined. Predominant chemical constituents are defined as those anions, cations, and compounds presenting over 99 percent of the routine risks to workers or members of the public. Toxic chemicals and those chemical constituents in tanks that present the 99 percentile hazards to groundwater and air are identified.

Boothe

1996-01-01

351

Carbon Doping of Compound Semiconductor Epitaxial Layers Grown by Metalorganic Chemical Vapor Deposition Using Carbon Tetrachloride.  

NASA Astrophysics Data System (ADS)

A dilute mixture of CCl_4 in high purity H_2 has been used as a carbon dopant source for rm Al_ {x}Ga_{1-x}As grown by low pressure metalorganic chemical vapor deposition (MOCVD). To understand the mechanism for carbon incorporation from CCl_4 doping and to provide experimental parameters for the growth of carbon doped device structures, the effects of various crystal growth parameters on CCl _4 doping have been studied, including growth temperature, growth rate, V/III ratio, Al composition, and CCl_4 flow rate. Although CCl _4 is an effective p-type dopant for MOCVD rm Al_{x}Ga_ {1-x}As, injection of CCl_4 into the reactor during growth of InP resulted in no change in the carrier concentration or carbon concentration. Abrupt, heavy carbon doping spikes in GaAs have been obtained using CCl_4 without a dopant memory effect. By annealing samples with carbon doping spikes grown within undoped, n-type, and p-type GaAs, the carbon diffusion coefficient in GaAs at 825 ^circC has been estimated and has been found to depend strongly on the GaAs background doping. Heavily carbon doped rm Al_{x}Ga _{1-x}As/GaAs superlattices have been found to be more stable against impurity induced layer disordering (IILD) than Mg or Zn doped superlattices, indicating that the low carbon diffusion coefficient limits the IILD process. Carbon doping has been used in the base region on an Npn AlGaAs/GaAs heterojunction bipolar transistor (HBT). Transistors with 3 x 10 ?m self-aligned emitter fingers have been fabricated which exhibit a current gain cutoff frequency of f_ {rm t} = 26 GHz.

Cunningham, Brian Thomas

1990-01-01

352

A Computational Approach for Identifying the Chemical Factors Involved in the Glycosaminoglycans-Mediated Acceleration of Amyloid Fibril Formation  

PubMed Central

Background Amyloid fibril formation is the hallmark of many human diseases, including Alzheimer's disease, type II diabetes and amyloidosis. Amyloid fibrils deposit in the extracellular space and generally co-localize with the glycosaminoglycans (GAGs) of the basement membrane. GAGs have been shown to accelerate the formation of amyloid fibrils in vitro for a number of protein systems. The high number of data accumulated so far has created the grounds for the construction of a database on the effects of a number of GAGs on different proteins. Methodology/Principal Findings In this study, we have constructed such a database and have used a computational approach that uses a combination of single parameter and multivariate analyses to identify the main chemical factors that determine the GAG-induced acceleration of amyloid formation. We show that the GAG accelerating effect is mainly governed by three parameters that account for three-fourths of the observed experimental variability: the GAG sulfation state, the solute molarity, and the ratio of protein and GAG molar concentrations. We then combined these three parameters into a single equation that predicts, with reasonable accuracy, the acceleration provided by a given GAG in a given condition. Conclusions/Significance In addition to shedding light on the chemical determinants of the protein?GAG interaction and to providing a novel mathematical predictive tool, our findings highlight the possibility that GAGs may not have such an accelerating effect on protein aggregation under the conditions existing in the basement membrane, given the values of salt molarity and protein?GAG molar ratio existing under such conditions. PMID:20613870

Monsellier, Elodie; Ramazzotti, Matteo; Taddei, Niccolò; Chiti, Fabrizio

2010-01-01

353

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

" or a "base" in the following reactions, and identify "conjugate" relationships. -You should have one acid?) 27. 28. G. For the following acid-base reaction, a. put a box around the weakest base in the reactionOrganic Chemistry Jasperse Acid-Base Practice Problems A. Identify each chemical as either an "acid

Jasperse, Craig P.

354

Photocatalytic and chemical oxidation of organic compounds in supercritical carbon dioxide. Progress report for FY97  

SciTech Connect

'The background for the project is briefly reviewed and the work done during the nine months since funding was received is documented. Work began in January, 1997. A post doctoral fellow joined the team in April. The major activities completed this fiscal year were: staffing the project, design of the experimental system, procurement of components, assembly of the system. preparation of the Safe Operating Procedure and ES and H compliance, pressure testing, establishing data collection and storage methodology, and catalyst preparation. Objective The objective of the project is to develop new chemistry for the removal of organic contaminants from supercritical carbon dioxide. This has application in processes used for continuous cleaning and extraction of parts and waste materials. A secondary objective is to increase the fundamental understanding of photocatalytic chemistry. Cleaning and extraction using supercritical carbon dioxide (scCO{sub 2}) can be applied to the solution of a wide range of environmental and pollution prevention problems in the DOE complex. Work is being done that explores scCO{sub 2} in applications ranging from cleaning contaminated soil to cleaning components constructed from plutonium. The rationale for use of scCO{sub 2} are based on the benign nature, availability and low cost, attractive solvent properties, and energy efficient separation of the extracted solute from the solvent by moderate temperature or pressure changes. To date, R and D has focussed on the methods and applications of the extraction steps of the process. Little has been done that addresses methods to polish the scCO{sub 2} for recycle in the cleaning or extraction operations. In many applications it will be desirable to reduce the level of contamination from that which would occur at steady state operation of a process. This proposal addresses chemistry to achieve that. This would be an alternative to removing a fraction of the contaminated scCO{sub 2} for disposal and using makeup scCO{sub 2}. A chemical polishing operation can reduce the release of CO{sub 2} from the process. It can also reduce the consumption of reagents that may be used in the process to enhance extraction and cleaning. A polishing operation will also reduce or avoid formation of an additional waste stream. Photocatalytic and other photochemical oxidation chemistry have not been investigated in scCO{sub 2}. The large base of information for these reactions in water, organic solvents, or air suggest that the chemistry will work in carbon dioxide. There are compelling reasons to believe that the properties of scCO{sub 2} should increase the performance of photocatalytic chemistry over that found in more conventional fluid phases.'

Blake, D.M.; Bryant, D.L.; Reinsch, V.

1997-09-30

355

Non-invasive identification of chemical compounds by energy dispersive X-ray fluorescence spectrometry, combined with chemometric methods of data evaluation  

Microsoft Academic Search

Chemicals from customers’ returns have to be analyzed before they can be reused as raw materials in production. A procedure\\u000a for non-invasive qualitative analysis of compounds in a closed container based on energy dispersive X-ray fluorescence (EDXRF)\\u000a spectrometry is described. EDXRF was chosen as method for non-invasive analysis of chemicals through PE bottle walls without\\u000a opening the bottle. This analysis

A. Henrich; P. Hoffmann; H. M. Ortner; T. Greve; H. Itzel

2000-01-01

356

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...

357

Chemical genomics approach to identify genes associated with sensitivity to rapamycin in the fission yeast Schizosaccharomyces pombe.  

PubMed

Rapamycin and its derivatives have now emerged as an attractive therapeutic strategy with both immunosuppressant and antitumor properties. In addition, rapamycin has been proposed as a calorie restriction mimetic to extend the life span of various organisms. The fission yeast Schizosaccharomyces pombe (S. pombe) serves as a valuable genetic model system to study the mechanism(s) of drug action as well as to determine genetic contexts associated with drug sensitivity or resistance. Here, we identified genes that when deleted modulate the rapamycin-sensitive strains in S. pombe. We carried out a chemical genomics screen for rapamycin-sensitive mutants using the genome-deletion library which covers 95.3% of all nonessential fission yeast genes and confirmed 59 genes to be rapamycin sensitive. Gene Ontology (GO) enrichment analysis showed that strains sensitive to rapamycin are highly enriched in processes regulating tRNA modification and mitochondria as well as other ontologies, including cellular metabolic process, chromatin organization, cell cycle, signaling, translation, transport and other cellular processes. Analysis also showed that components of the Elongator complex are overrepresented in the sensitive strains. Here, the data obtained will provide valuable information for speculation on the actions of rapamycin as well as on TORC signaling, thereby presenting a strategy to enhance sensitivity to rapamycin. PMID:25651869

Doi, Akira; Fujimoto, Ayumi; Sato, Shun; Uno, Takaya; Kanda, Yuki; Asami, Keita; Tanaka, Yuriko; Kita, Ayako; Satoh, Ryosuke; Sugiura, Reiko

2015-04-01

358

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

EPA Science Inventory

Metabolomics analysis was performed on the supernatant of human embryonic stem (hES) cell cultures exposed to a blinded subset of 11 chemicals selected from the chemical library of EPA's ToxCast? chemical screening and prioritization research project. Metabolites from hES cultur...

359

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

360

Magnesium compounds  

USGS Publications Warehouse

Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

Kramer, D.A.

2003-01-01

361

Whole-exome sequencing identifies novel compound heterozygous mutations in USH2A in Spanish patients with autosomal recessive retinitis pigmentosa  

PubMed Central

Purpose Retinitis pigmentosa (RP) is an inherited retinal dystrophy characterized by extreme genetic and clinical heterogeneity. Thus, the diagnosis is not always easily performed due to phenotypic and genetic overlap. Current clinical practices have focused on the systematic evaluation of a set of known genes for each phenotype, but this approach may fail in patients with inaccurate diagnosis or infrequent genetic cause. In the present study, we investigated the genetic cause of autosomal recessive RP (arRP) in a Spanish family in which the causal mutation has not yet been identified with primer extension technology and resequencing. Methods We designed a whole-exome sequencing (WES)-based approach using NimbleGen SeqCap EZ Exome V3 sample preparation kit and the SOLiD 5500×l next-generation sequencing platform. We sequenced the exomes of both unaffected parents and two affected siblings. Exome analysis resulted in the identification of 43,204 variants in the index patient. All variants passing filter criteria were validated with Sanger sequencing to confirm familial segregation and absence in the control population. In silico prediction tools were used to determine mutational impact on protein function and the structure of the identified variants. Results Novel Usher syndrome type 2A (USH2A) compound heterozygous mutations, c.4325T>C (p.F1442S) and c.15188T>G (p.L5063R), located in exons 20 and 70, respectively, were identified as probable causative mutations for RP in this family. Family segregation of the variants showed the presence of both mutations in all affected members and in two siblings who were apparently asymptomatic at the time of family ascertainment. Clinical reassessment confirmed the diagnosis of RP in these patients. Conclusions Using WES, we identified two heterozygous novel mutations in USH2A as the most likely disease-causing variants in a Spanish family diagnosed with arRP in which the cause of the disease had not yet been identified with commonly used techniques. Our data reinforce the clinical role of WES in the molecular diagnosis of highly heterogeneous genetic diseases where conventional genetic approaches have previously failed in achieving a proper diagnosis. PMID:24227914

Méndez-Vidal, Cristina; González-del Pozo, María; Vela-Boza, Alicia; Santoyo-López, Javier; López-Domingo, Francisco J.; Vázquez-Marouschek, Carmen; Dopazo, Joaquin; Borrego, Salud

2013-01-01

362

Impact of the chemical and physical stability of ketoprofen compounded in various pharmaceutical bases on its topical and transdermal delivery.  

PubMed

Abstract Increasing demands for individualized drug treatment has led to an increase in the practice of compounded medications. In this study, we determined the impact of the chemical and physical stability of ketoprofen (10%w/w) cream on its topical/transdermal delivery over a 6-month period. The shelf life of ketoprofen at 25?°C in the pharmaceutical bases LipoDerm and LipoBase (109.94 and 85.9 days) was significantly longer than that in Pluronic Lecithin Organogel (PLO; 44.81 days), justifying extending its beyond use date (BUD) from 30 (USP37/NF32) to at least 60 days in LipoDerm and LipoBase. All the creams evaluated exhibited shear-thinning flow behavior with moderate thixotropy, while the flow properties for LipoBase and PLO creams were altered at storage times greater than 90 days. The percentage of ketoprofen permeated through porcine ear skin was 13.7, 19.1 and 12.7% of the dose from LipoDerm, LipoBase and PLO, respectively and decreased 2- to 3-fold after 28 days of storage. Flux ranging from 85.3 to 446.7?µg/cm(2)/h and topical delivery, on the other hand, were not influenced by storage duration past 28 days. In conclusion, this study justifies extending the BUD of ketoprofen in LipoDerm and LipoBase to 60 days if used for topical delivery only. PMID:25431959

Nornoo, Adwoa O; Wulz, Jordan; Yoon, Haena; Nan, Yu; Lese, Michele

2014-11-28

363

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-Pérez, Kellymar; Hanson, Bryan A.; Raftery, Daniel

2010-01-01

364

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

365

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

366

Aspherical-atom modeling of coordination compounds by single-crystal X-ray diffraction allows the correct metal atom to be identified.  

PubMed

Single-crystal X-ray diffraction (XRD) is often considered the gold standard in analytical chemistry, as it allows element identification as well as determination of atom connectivity and the solid-state structure of completely unknown samples. Element assignment is based on the number of electrons of an atom, so that a distinction of neighboring heavier elements in the periodic table by XRD is often difficult. A computationally efficient procedure for aspherical-atom least-squares refinement of conventional diffraction data of organometallic compounds is proposed. The iterative procedure is conceptually similar to Hirshfeld-atom refinement (Acta Crystallogr. Sect. A- 2008, 64, 383-393; IUCrJ. 2014, 1,61-79), but it relies on tabulated invariom scattering factors (Acta Crystallogr. Sect. B- 2013, 69, 91-104) and the Hansen/Coppens multipole model; disordered structures can be handled as well. Five linear-coordinate 3d metal complexes, for which the wrong element is found if standard independent-atom model scattering factors are relied upon, are studied, and it is shown that only aspherical-atom scattering factors allow a reliable assignment. The influence of anomalous dispersion in identifying the correct element is investigated and discussed. PMID:25393218

Dittrich, Birger; Wandtke, Claudia M; Meents, Alke; Pröpper, Kevin; Mondal, Kartik Chandra; Samuel, Prinson P; Amin Sk, Nurul; Singh, Amit Pratap; Roesky, Herbert W; Sidhu, Navdeep

2015-02-01

367

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

368

Chemical vapor deposition and characterization of polysilanes polymer based thin films and their applications in compound semiconductors and silicon devices  

NASA Astrophysics Data System (ADS)

As the semiconductors industry is moving toward nanodevices, there is growing need to develop new materials and thin films deposition processes which could enable strict control of the atomic composition and structure of thin film materials in order to achieve precise control on their electrical and optical properties. The accurate control of thin film characteristics will become increasingly important as the miniaturization of semiconductor devices continue. There is no doubt that chemical synthesis of new materials and their self assembly will play a major role in the design and fabrication of next generation semiconductor devices. The objective of this work is to investigate the chemical vapor deposition (CVD) process of thin film using a polymeric precursor as a source material. This process offers many advantages including low deposition cost, hazard free working environment, and most importantly the ability to customize the polymer source material through polymer synthesis and polymer functionalization. The combination between polymer synthesis and CVD process will enable the design of new generation of complex thin film materials with a wide range of improved chemical, mechanical, electrical and optical properties which cannot be easily achieved through conventional CVD processes based on gases and small molecule precursors. In this thesis we mainly focused on polysilanes polymers and more specifically poly(dimethylsilanes). The interest in these polymers is motivated by their distinctive electronic and photonic properties which are attributed to the delocalization of the sigma-electron along the Si-Si backbone chain. These characteristics make polysilane polymers very promising in a broad range of applications as a dielectric, a semiconductor and a conductor. The polymer-based CVD process could be eventually extended to other polymer source materials such as polygermanes, as well as and a variety of other inorganic and hybrid organic-inorganic polymers. This work has demonstrated that a polysilane polymeric source can be used to deposit a wide range of thin film materials exhibiting similar properties with conventional ceramic materials such as silicon carbide (SiC), silicon oxynitride (SiON), silicon oxycarbide (SiOC) silicon dioxide (SiO2) and silicon nitride (Si3N4). The strict control of the deposition process allows precise control of the electrical, optical and chemical properties of polymer-based thin films within a broad range. This work has also demonstrated for the first time that poly(dimethylsilmaes) polymers deposited by CVD can be used to effectively passivate both silicon and gallium arsenide MOS devices. This finding makes polymer-based thin films obtained by CVD very promising for the development of high-kappa dielectric materials for next generation high-mobility CMOS technology. Keywords. Thin films, Polymers, Vapor Phase Deposition, CVD, Nanodielectrics, Organosilanes, Polysilanes, GaAs Passivation, MOSFET, Silicon Oxynitride, Integrated Waveguide, Silicon Carbide, Compound Semiconductors.

Oulachgar, El Hassane

369

Relationship between gas chromatographic retention indices and chemical shifts in the 13C NMR spectra of structural isomers of compounds of tetracoordinated phosphorus  

NASA Astrophysics Data System (ADS)

A method for determining the gas chromatographic retention indices of structural isomers of compounds of tetracoordinated phosphorus, based on the correlation between chemical shifts in 13C nuclear magnetic resonance (NMR) spectra and the retention indices of the structural isomers, and on the theory of intermolecular interactions, is proposed. The capabilities of the method are demonstrated for structural isomers of O-alkylmethylfluorophosphonates, which are typical representatives of compounds from the class of tetracoordinated phosphonates. The results from using the correlation approach are compared to experimental data.

Zhokhov, A. K.; Fomenko, P. V.; Aparkin, A. M.; Belousov, E. B.

2015-01-01

370

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

PubMed Central

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

2014-01-01

371

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...

372

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

PubMed

The NMR spectrum of a mixture of small molecules is a fingerprint of all of its components. Herein, we present an NMR fingerprint method that takes advantage of the fact that fractions contain simplified NMR profiles, with minimal signal overlap, to allow the identification of unique spectral patterns. The approach is exemplified in the identification of a novel natural product, iotrochotazine?A (1), sourced from an Australian marine sponge Iotrochota?sp. Compound 1 was used as a chemical probe in a phenotypic assay panel based on human olfactory neurosphere-derived cells (hONS) from idiopathic Parkinson's disease patients. Compound 1 at 1??M was not cytotoxic but specifically affected the morphology and cellular distribution of lysosomes and early endosomes. PMID:24737726

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

2014-06-10

373

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

374

[Chemical constituents of Alyxia levinei Merr].  

PubMed

Three compounds were isolated from the stem and leaves of Alyxia levinei. On the basis of spectrometric analysis and physico-chemical constants they were identified as oleanolic acid, betulin and beta-sitosterol-D-glucoside respectively. PMID:1863334

Yuan, A; Du, S; Qin, L

1991-04-01

375

Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter  

SciTech Connect

Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 ?M of each tetracycline-derived compound 20 min prior to exposure to 500 ?M iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs–Ringer–HEPES buffer at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca{sup 2+} uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca{sup 2+} uptake and suppressed the Ca{sup 2+}-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca{sup 2+} uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. - Highlights: • Minocycline and doxycycline are the only cytoprotective tetracyclines of those tested • Cytoprotective tetracyclines inhibit the MPT and mitochondrial calcium and iron uptake. • Cytoprotective tetracyclines protect by inhibiting the MCU.

Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L.; Smith, Charles D. [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Lemasters, John J., E-mail: JJLemasters@musc.edu [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC (United States)

2013-11-15

376

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

377

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 Central

Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 ?M of each tetracycline-derived compound 20 min prior to exposure to 500 ?M iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs-Ringer-Hepes buffer (KRH) at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca2+ 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) fluorometery 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 Ca2+ uptake and suppressed the Ca2+-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 Ca2+ 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.

2015-01-01

378

Amorphous nanowires and crystalline thin films of SiO2 Li2O compounds obtained by combustion chemical vapour deposition  

Microsoft Academic Search

Amorphous silica films deposited by combustion chemical vapour deposition (CCVD) were modified by lithium addition in the precursor solution. The modified films were characterized by x-ray diffraction and scanning and transmission electron microscopy. The addition of lithium promoted the crystallization of Li2O-SiO2 compounds, mainly crystalline phases like Li2SiO3, Li2Si2O5, quartz and cristobalite. Besides this, the morphology of the film was

M. D. Lima; M. J. de Andrade; S. Stein; R. Bonadiman; C. P. Bergmann

2005-01-01

379

Amorphous nanowires and crystalline thin films of SiO2–Li2O compounds obtained by combustion chemical vapour deposition  

Microsoft Academic Search

Amorphous silica films deposited by combustion chemical vapour deposition (CCVD) were modified by lithium addition in the precursor solution. The modified films were characterized by x-ray diffraction and scanning and transmission electron microscopy. The addition of lithium promoted the crystallization of Li2O–SiO2 compounds, mainly crystalline phases like Li2SiO3, Li2Si2O5, quartz and cristobalite. Besides this, the morphology of the film was

M D Lima; M J de Andrade; S Stein; R Bonadiman; C P Bergmann

2005-01-01

380

A SAW-Based Chemical Sensor for Detecting Sulfur-Containing Organophosphorus Compounds Using a Two-Step Self-Assembly and Molecular Imprinting Technology  

PubMed Central

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

381

Direct quantification of chemical warfare agents and related compounds at low ppt levels: comparing active capillary dielectric barrier discharge plasma ionization and secondary electrospray ionization mass spectrometry.  

PubMed

A novel active capillary dielectric barrier discharge plasma ionization (DBDI) technique for mass spectrometry is applied to the direct detection of 13 chemical warfare related compounds, including sarin, and compared to secondary electrospray ionization (SESI) in terms of selectivity and sensitivity. The investigated compounds include an intact chemical warfare agent and structurally related molecules, hydrolysis products and/or precursors of highly toxic nerve agents (G-series, V-series, and "new" nerve agents), and blistering and incapacitating warfare agents. Well-defined analyte gas phase concentrations were generated by a pressure-assisted nanospray with consecutive thermal evaporation and dilution. Identification was achieved by selected reaction monitoring (SRM). The most abundant fragment ion intensity of each compound was used for quantification. For DBDI and SESI, absolute gas phase detection limits in the low ppt range (in MS/MS mode) were achieved for all compounds investigated. Although the sensitivity of both methods was comparable, the active capillary DBDI sensitivity was found to be dependent on the applied AC voltage, thus enabling direct tuning of the sensitivity and the in-source fragmentation, which may become a key feature in terms of field applicability. Our findings underline the applicability of DBDI and SESI for the direct, sensitive detection and quantification of several CWA types and their degradation products. Furthermore, they suggest the use of DBDI in combination with hand-held instruments for CWAs on-site monitoring. PMID:25427190

Wolf, Jan-Christoph; Schaer, Martin; Siegenthaler, Peter; Zenobi, Renato

2015-01-01

382

Chemical effects on K?/K? X-ray intensity ratios of Mo, Ag, Cd, Ba, La, Ce compounds and total mass attenuation coefficients of Fe and Cu  

NASA Astrophysics Data System (ADS)

The K?/K? intensity ratios for pure Mo, Ag, Cd, Ba, La and Ce elements and for some of their compounds were investigated. The vacancies in the K shell were created by 59.5-keV ?-rays from a heavily filtered 241Am radioactive source. K X-rays were measured using a Si(Li) detector with a resolution of 155 eV at 5.9 keV. We observed chemical effects on K?/K? intensity ratios of Mo, Ag, Cd, Ba, La and Ce compounds. Detailed interpretation of data obtained from X-ray transmission measurements usually depends on the assumption that the contribution of each element is additive. This assumption yields the mixture rule for X-ray attenuation coefficients which is valid if molecular and chemical effects are negligible. We measured the total mass attenuation coefficients of Fe and Cu in various compounds. Self-absorption corrections were carried out on data for ligands in the different compounds. Our values were compared with the theoretical values for pure elements.

Sögüt, Ö.; Seven, S.; Baydas, E.; Büyükkasap, E.; Küçükönder, A.

2001-08-01

383

CARBON-13 NUCLEAR MAGNETIC RESONANCE. 13C CHEMICAL SHIFTS AND 13C-199HG COUPLING CONSTANTS FOR SOME ORGANOMERCURY COMPOUNDS  

EPA Science Inventory

The (13)C shieldings and (13)C-(199)Hg coupling constants of fourteen phenyl- and seven alkyl- and alkenyl-mercury compounds have been obtained. Substituent effects on the (13)C shieldings are similar to those in nonmercurated phenyl compounds, with a similar relationship between...

384

Chemical synthesis of two series of nerve agent model compounds and their stereoselective interaction with human acetylcholinesterase and human butyrylcholinesterase  

PubMed Central

Both G- and V-type nerve agents possess a center of chirality about phosphorus. The Sp-enantiomers are generally more potent inhibitors than their Rp-counterparts toward acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). To develop model compounds with defined centers of chirality that mimic the target nerve agent structures, we synthesized both the Sp and Rp stereoisomers of two series of G-type nerve agent model compounds in enantiomerically enriched form. The two series of model compounds contained identical substituents on the phosphorus as the G-type agents, except that thiomethyl (CH3-S-) and thiocholine ((CH3)3NCH2CH2-S-) groups were used to replace the traditional nerve agent leaving groups (i.e., fluoro for GB, GF, and GD; and cyano for GA). Inhibition kinetic studies of the thiomethyl- and thiocholine-substituted series of nerve agent model compounds revealed that the Sp enantiomers of both series of compounds showed greater inhibition potency toward AChE and BChE. The level of stereoselectivity, as indicated by the ratio of the bimolecular inhibition rate constants between Sp and Rp enantiomers, was greatest for the GF model compounds in both series. The thiocholine analogs were much more potent than the corresponding thiomethyl analogs. With the exception of the GA model compounds, both series showed greater potency against AChE than BChE. The stereoselectivity (i.e., Sp > Rp), enzyme selectivity, and dynamic range of inhibition potency contributed from these two series of compounds suggest that the combined application of these model compounds will provide useful research tools for understanding interactions of nerve agents with cholinesterase and other enzymes involved in nerve agent and organophosphate pharmacology. The potential of and limitations for using these model compounds in the development of biological therapeutics against nerve agent toxicity are also discussed. PMID:19715346

Barakat, Nora H.; Zheng, Xueying; Gilley, Cynthia B.; MacDonald, Mary; Okolotowicz, Karl; Cashman, John R.; Vyas, Shubham; Beck, Jeremy M.; Hadad, Christopher M.; Zhang, Jun

2009-01-01

385

Identifying past earthquakes on an active normal fault (Magnola, Italy) from the chemical analysis of its exhumed carbonate fault plane  

Microsoft Academic Search

A normal fault scarp exhumed by repeated strong earthquakes is made of a series of rupture zones that were exposed, thus weathered, over significantly different time spans. We show that such differential weathering can be detected in the chemical content of the fault scarp rocks, and its signature used as a base to decipher the past earthquake history of the

Julien Carcaillet; Isabelle Manighetti; Catherine Chauvel; Aloé Schlagenhauf; Jean-Marc Nicole

2008-01-01

386

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

387

40 CFR 721.9597 - Salt of a substituted sulfonated aryl azo compound (generic).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Salt of a substituted sulfonated aryl azo compound...Specific Chemical Substances § 721.9597 Salt of a substituted sulfonated aryl azo compound...chemical substance identified generically as salt of a substituted sulfonated aryl...

2011-07-01

388

40 CFR 721.9597 - Salt of a substituted sulfonated aryl azo compound (generic).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Salt of a substituted sulfonated aryl azo compound...Specific Chemical Substances § 721.9597 Salt of a substituted sulfonated aryl azo compound...chemical substance identified generically as salt of a substituted sulfonated aryl...

2010-07-01

389

40 CFR 721.9597 - Salt of a substituted sulfonated aryl azo compound (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Salt of a substituted sulfonated aryl azo compound...Specific Chemical Substances § 721.9597 Salt of a substituted sulfonated aryl azo compound...chemical substance identified generically as salt of a substituted sulfonated aryl...

2012-07-01

390

Magnesium compounds  

USGS Publications Warehouse

Seawater and natural brines accounted for about 63% of US magnesium compounds production during 2000. Premier Services in Florida, Dow Chemical in Michigan, Martin Marietta Magnesia Specialties, and Rohm & Haas recovered dead-burned and caustic-calcined magnesias from seawater. And Premier Services' recoveries, in Nevada, were from magnasite.

Kramer, D.A.

2001-01-01

391

Identifying military impacts on archaeology deposits based on differences in soil organic carbon and chemical elements at soil horizon interfaces  

Technology Transfer Automated Retrieval System (TEKTRAN)

The National Historic Preservation Act requires land-managing agencies to identify and account for their impacts on archaeological resources. Regulatory agencies that oversee compliance with historic preservation legislation frequently assume military training adversely affects archaeological resou...

392

Using Synchrotron-based X-ray Absorption Spectrometry to Identify the Arsenic Chemical Forms in Mine Waste Materials  

SciTech Connect

X-ray Absorption Near Edge Spectroscopy (XANES) gives arsenic form directly in the solid phase and has lower detection limits than extraction techniques. An important and common application of XANES is to use the shift of the edge position to determine the valence state. XANES speciation analysis is based on fitting linear combinations of known spectra from model compounds to determine the ratios of valence states and/or phases present. As(V)/As(III) ratios were determined for various Australian mine waste samples and dispersed mine waste samples from river/creek sediments in Vatukoula, Fiji.

Matanitobua, Vitukawalu P.; Noller, Barry N.; Chiswell, Barry; Ng, Jack C.; Bruce, Scott L.; Huang, Daphne [National Research Centre for Environmental Toxicology (EnTox), University of Queensland, 39 Kessels Road, Coopers Plains, Queensland 4108 (Australia); Riley, Mark [Chemistry Department, School of Molecular and Microbial Sciences, University of Queensland, St Lucia, Queensland 4067 (Australia); Harris, Hugh H. [School of Chemistry, University of Sydney, New South Wales 2006 (Australia)

2007-01-19

393

Magnesium compounds  

USGS Publications Warehouse

Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

Kramer, D.A.

2002-01-01

394

Magnesium compounds  

USGS Publications Warehouse

Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

Kramer, D.A.

2010-01-01

395

40 CFR 721.3320 - Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine (1:1).  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine...Specific Chemical Substances § 721.3320 Ethanol, 2-amino-, com-pound with N -hydroxy-N...The chemical substance identified as ethanol, 2-amino-, compound with N...

2014-07-01

396

40 CFR 721.3320 - Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine (1:1).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine...Specific Chemical Substances § 721.3320 Ethanol, 2-amino-, com-pound with N -hydroxy-N...The chemical substance identified as ethanol, 2-amino-, compound with N...

2013-07-01

397

40 CFR 721.3320 - Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine (1:1).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine...Specific Chemical Substances § 721.3320 Ethanol, 2-amino-, com-pound with N -hydroxy-N...The chemical substance identified as ethanol, 2-amino-, compound with N...

2012-07-01

398

Solutia: Massachusetts Chemical Manufacturer Uses SECURE Methodology to Identify Potential Reductions in Utility and Process Energy Consumption  

SciTech Connect

This case study prepared for the U.S. Department of Energy's Industrial Technologies Program describes a plant-wide energy assessment conducted at the Solutia Inc. chemical production facility in Springfield, Massachusetts. Solutia manufactures polymers, intermediates, and chemicals for a variety of products. The assessment focused on finding ways to reduce the plant's use of steam, electricity, compressed air, and water. If the company were to implement all the recommendations that came out of the assessment, its total annual energy savings could be about 9.6 million kWh for electricity and more than 338,000 MBtu for natural gas. Annual cost savings could amount to nearly $3.3 million.

Not Available

2005-07-01

399

A High-Throughput Screen with Isogenic PTEN+/+ and PTEN?/? Cells Identifies CID1340132 as a Novel Compound That Induces Apoptosis in PTEN and PIK3CA Mutant Human Cancer Cells  

PubMed Central

The PTEN tumor suppressor gene is one of the most commonly mutated genes in human cancer. Because inactivation of PTEN is a somatic event, PTEN mutations represent an important genetic difference between cancer cells and normal cells and therefore a potential anticancer drug target. However, it remains a substantial challenge to identify compounds that target loss-of-function events such as mutations of tumor suppressors. In an effort to identify small molecules that preferentially kill cells with mutations of PTEN, the authors developed and implemented a high-throughput, paired cell-based screen composed of parental HCT116 cells and their PTEN gene-targeted derivatives. From 138 758 compounds tested, two hits were identified, and one, N?-[(1-benzyl-1H-indol-3-yl)methylene]benzenesulfonohydrazide (CID1340132), was further studied using a variety of cell-based models, including HCT116, MCF10A, and HEC1A cells with targeted deletion of either their PTEN or PIK3CA genes. Preferential killing of PTEN and PIK3CA mutant cells was accompanied by DNA damage, inhibition of DNA synthesis, and apoptosis. taken together, these data validate a cell-based screening approach for identifying lead compounds that target cells with specific tumor suppressor gene mutations and describe a novel compound with preferential killing activity toward PTEN and PIK3CA mutant cells. PMID:21335596

Li, Hui-Fang; Keeton, Adam; Vitolo, Michele; Maddox, Clinton; Rasmussen, Lynn; Hobrath, Judith; White, E. Lucille; Park, Ben Ho; Piazza, Gary A.; Kim, Jung-Sik; Waldman, Todd

2013-01-01

400

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

401

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

402

Establishment and Validation of Whole-Cell Based Fluorescence Assays to Identify Anti-Mycobacterial Compounds Using the Acanthamoeba castellanii - Mycobacterium marinum Host-Pathogen System  

PubMed Central

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

403

Combined effect of boron compounds and heat treatments on wood properties: Chemical and strength properties of wood  

Microsoft Academic Search

This study evaluated the effects of boron impregnation and heat treatment on the chemical and mechanical properties of wood. Sugi (Cryptomeria japonica D. Don) sapwood specimens treated with either boric acid (BA) or di-sodium octoborate tetrahydrate (DOT) solutions were exposed to heat treatments at either 180 or 220°C for 2 or 4h. Chemical composition and strength properties were then measured

S. Nami Kartal; Won-Joung Hwang; Yuji Imamura

2008-01-01

404

Crystallographic properties of fertilizer compounds  

SciTech Connect

This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA's fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

1991-02-01

405

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...

406

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

407

Influence of cooking on the levels of bioactive compounds in Purple Majesty potato observed via chemical and spectroscopic means.  

PubMed

Tubers rich in phytochemicals can exhibit a potential health benefit. This work aims at studying the relative effect of different domestic cooking techniques by monitoring the level of total phenolic compounds (TP), total anthocyanins (TA) and anti-oxidant activity (AOA) on a variety of pigmented potatoes. Raw purple potatoes are a good source of anthocyanins (219 mg/kg FW) and the level of these compounds increased using different cooking techniques, with the exception of baking. However, the levels of phenolic compounds (originally 209 mg GAE/100 g FW) decreased in the cooked potatoes. Although potatoes contain different antioxidants in this work the antioxidant activity seems to be related to the levels of phenolic compounds present in the pigmented potato. The fact that some of the compounds present fluoresce enabled both steady state and time-resolved fluorescence techniques to be assessed as a non destructive means of monitoring. This elucidated the presence of different components (via spectral deconvolution and time-resolved emission spectra). Their relative contribution to the fluorescence emission was found to be affected by the different cooking process, with a longer wavelength emission appearing to relate to reflect the presence of anthocyanins. PMID:25466046

Lemos, M Adília; Aliyu, Maryam M; Hungerford, Graham

2015-04-15

408

USE OF THE FUNGICIDE CARBENDAZIM AS A MODEL COMPOUND TO DETERMINE THE IMPACT OF ACUTE CHEMICAL EXPOSURE DURING OOCYTE MATURATION AND FERTILIZATION ON PREGNANCY OUTCOME IN THE HAMSTER  

EPA Science Inventory

Here we use a hamster animal model to identify early pregnancy loss due to an acute chemical exposure to the female during the perifertilization interval. The fungicide carbendazim (methyl 1H-benzimidazole-2-carbamate), a microtubule poison with antimitotic activity, was selected...

409

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...

410

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...

411

Complementary standoff chemical imaging to map and identify artist materials in an early Italian Renaissance panel painting.  

PubMed

Two imaging modalities based on molecular and elemental spectroscopy were used to characterize a painting by Cosimo Tura. Visible-to-near-infrared (400-1680?nm) reflectance imaging spectroscopy (RIS) and X-ray fluorescence (XRF) imaging spectroscopy were employed to identify pigments and determine their spatial distribution with higher confidence than from either technique alone. For example, Mary's red robe was modeled through the distribution of an insect-derived red lake (RIS map) and lead white (XRF lead map), rather than a layer of red lake on vermilion. The RIS image cube was also used to isolate the preparatory design by mapping the reflectance spectra associated with it. In conjunction with results from an earlier RIS study (1650-2500?nm) to map and identify the binding media, a more thorough understanding was gained of the materials and techniques used in the painting. PMID:25319091

Dooley, Kathryn A; Conover, Damon M; Glinsman, Lisha Deming; Delaney, John K

2014-12-01

412

Identifying the unknowns by aligning fragmentation trees.  

PubMed

Mass spectrometry allows sensitive, automated, and high-throughput analysis of small molecules. In principle, tandem mass spectrometry allows us to identify "unknown" small molecules not in any database, but the automated interpretation of such data is in its infancy. Fragmentation trees have recently been introduced for the automated analysis of the fragmentation patterns of small molecules. We present a method for the automated comparison of such fragmentation patterns, based on aligning the compounds' fragmentation trees. We cluster compounds based solely on their fragmentation patterns and show a good agreement with known compound classes. Fragmentation pattern similarities are strongly correlated with the chemical similarity of molecules. We present a tool for searching a database for compounds with fragmentation pattern similar to an unknown sample compound. We apply this tool to metabolites from Icelandic poppy. Our method allows fully automated computational identification of small molecules that cannot be found in any database. PMID:22390817

Rasche, Florian; Scheubert, Kerstin; Hufsky, Franziska; Zichner, Thomas; Kai, Marco; Svatoš, Aleš; Böcker, Sebastian

2012-04-01

413

Laboratory and field experiments used to identify Canis lupus var. familiaris active odor signature chemicals from drugs, explosives, and humans  

Microsoft Academic Search

This paper describes the use of headspace solid-phase microextraction (SPME) combined with gas chromatography to identify the signature odors that law enforcement-certified detector dogs alert to when searching for drugs, explosives, and humans. Background information is provided on the many types of detector dog available and specific samples highlighted in this paper are the drugs cocaine and 3,4-methylenedioxy-N-methylamphetamine (MDMA or

Norma Lorenzo; TianLang Wan; Ross J. Harper; Ya-Li Hsu; Michael Chow; Stefan Rose; Kenneth G. Furton

2003-01-01

414

Chemical and Synthetic Genetic Array Analysis Identifies Genes that Suppress Xylose Utilization and Fermentation in Saccharomyces cerevisiae.  

PubMed

Though highly efficient at fermenting hexose sugars, Saccharomyces cerevisiae has limited ability to ferment five-carbon sugars. As a significant portion of sugars found in cellulosic biomass is the five-carbon sugar xylose, S. cerevisiae must be engineered to metabolize pentose sugars, commonly by the addition of exogenous genes from xylose fermenting fungi. However, these recombinant strains grow poorly on xylose and require further improvement through rational engineering or evolutionary adaptation