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Sample records for dialkyl squarate chemistry

  1. Synthesis of novel organic-inorganic hybrid compounds: lanthanide phosphites incorporating a squarate ligand.

    PubMed

    Wang, Chih-Min; Lii, Kwang-Hwa

    2009-07-20

    The first examples of metal phosphite incorporating a squarate anion as a ligand have been synthesized by a hydrothermal method. Their structures contain zigzag chains of edge-sharing LnO(8) (Ln = Sm, Eu, and Gd) square antiprisms connected by phosphite groups to form 2D layers, which are pillared by squarate ligands into a 3D framework. The photoluminescence properties of the Eu compound have also been studied.

  2. Novel polymerization catalysts and hydride clusters from rare-earth metal dialkyls.

    PubMed

    Nishiura, Masayoshi; Hou, Zhaomin

    2010-04-01

    This Review gives an overview on recent progress in the synthesis and chemistry of rare-earth metal dialkyl complexes bearing monoanionic ancillary ligands, with an emphasis on novel polymerization catalysts. These structurally well-defined and highly reactive compounds are prepared either by alkane elimination reactions between trialkyl rare-earth complexes and acidic neutral ligands, or by the metathetical reactions of rare-earth trihalides with the alkali metal salts of the corresponding ligands. On treatment with an appropriate borate compound, the dialkyl complexes are converted into the corresponding cationic monoalkyl species, which serve as excellent catalysts for the polymerization and copolymerization of a variety of olefins to yield a series of new polymer materials that exhibit novel properties. Alternatively, hydrogenation of the dialkyl rare-earth complexes with H(2) affords a new class of rare-earth polyhydride complexes with unique features in terms of both their structure and reactivity.

  3. Synthesis of N,N'-dialkyl-4'bipyridinium reagents

    DOEpatents

    Wrighton, Mark S.; Bookbinder, Dana C.

    1984-09-25

    A novel class of dialkyl and dialkyl-aromatic viologens (4,4'dipyridinium compounds) and their salts which may be polymerized and covalently bonded to electrodes for use in electronic display systems.

  4. 40 CFR 721.10560 - Alkanoldioic dialkyl esters (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkanoldioic dialkyl esters (generic... Specific Chemical Substances § 721.10560 Alkanoldioic dialkyl esters (generic). (a) Chemical substance and... dialkyl esters (PMNs P-07-143 and P-07-144) are subject to reporting under this section for...

  5. 40 CFR 721.10715 - Carbonic acid, dialkyl ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Carbonic acid, dialkyl ester (generic... Specific Chemical Substances § 721.10715 Carbonic acid, dialkyl ester (generic). (a) Chemical substance and..., dialkyl ester (PMN P-13-346) is subject to reporting under this section for the significant new...

  6. 40 CFR 721.10314 - Dialkyl dithiocarbamate esters (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Dialkyl dithiocarbamate esters... Specific Chemical Substances § 721.10314 Dialkyl dithiocarbamate esters (generic). (a) Chemical substance... dialkyl dithiocarbamate esters (PMNs P-02-778, P-02-779, and P-02-780) are subject to reporting under...

  7. 40 CFR 721.10560 - Alkanoldioic dialkyl esters (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkanoldioic dialkyl esters (generic... Specific Chemical Substances § 721.10560 Alkanoldioic dialkyl esters (generic). (a) Chemical substance and... dialkyl esters (PMNs P-07-143 and P-07-144) are subject to reporting under this section for...

  8. 40 CFR 721.10314 - Dialkyl dithiocarbamate esters (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Dialkyl dithiocarbamate esters... Specific Chemical Substances § 721.10314 Dialkyl dithiocarbamate esters (generic). (a) Chemical substance... dialkyl dithiocarbamate esters (PMNs P-02-778, P-02-779, and P-02-780) are subject to reporting under...

  9. 40 CFR 721.10314 - Dialkyl dithiocarbamate esters (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Dialkyl dithiocarbamate esters... Specific Chemical Substances § 721.10314 Dialkyl dithiocarbamate esters (generic). (a) Chemical substance... dialkyl dithiocarbamate esters (PMNs P-02-778, P-02-779, and P-02-780) are subject to reporting under...

  10. 40 CFR 721.5980 - Dialkyl phosphorodithioate phosphate compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Dialkyl phosphorodithioate phosphate... Specific Chemical Substances § 721.5980 Dialkyl phosphorodithioate phosphate compounds. (a) Chemical... as dialkyl phosphorodithioate phosphate compounds (P-90-1642 through 1649) are subject to...

  11. 40 CFR 721.5980 - Dialkyl phosphorodithioate phosphate compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Dialkyl phosphorodithioate phosphate... Specific Chemical Substances § 721.5980 Dialkyl phosphorodithioate phosphate compounds. (a) Chemical... as dialkyl phosphorodithioate phosphate compounds (P-90-1642 through 1649) are subject to...

  12. 40 CFR 721.5980 - Dialkyl phosphorodithioate phosphate compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Dialkyl phosphorodithioate phosphate... Specific Chemical Substances § 721.5980 Dialkyl phosphorodithioate phosphate compounds. (a) Chemical... as dialkyl phosphorodithioate phosphate compounds (P-90-1642 through 1649) are subject to...

  13. Synthesis, growth and characterization of a new nonlinear optical crystal: glycinium hydrogen squarate (GHS).

    PubMed

    Paramasivam, P; Ramachandra Raja, C

    2012-07-01

    Single crystals of glycinium hydrogen squarate (GHS) have been successfully synthesized and purity of the material has been increased by repeated recrystallization process. Single crystals were grown by slow evaporation solution growth technique using water and ethanol as solvents at room temperature. Then the grown crystal was characterized by different techniques for finding its suitability for device fabrications. The grown crystal was characterized by single crystal XRD, powder XRD, FT-IR, UV-Vis-NIR, (1)H NMR, (13)C NMR, SHG and DTA/TGA analyses respectively. From the single crystal XRD diffraction, the crystal system was identified as monoclinic. The presence of functional groups were identified by FT-IR analysis. The UV transparency cut-off wavelength of the grown crystal occurs at 342nm. (1)H NMR and (13)C NMR spectroscopic studies were employed to elucidate the structure of the grown crystal. The second harmonic generation efficiency test by Kurtz-Perry technique showed positive result. The decomposition temperature of the grown crystal was studied by DTA/TGA analysis. The results observed from the characterization analyses show its suitability for NLO applications.

  14. Study of heterogeneous catalysis by iron-squarate based 3D metal organic framework for the transformation of tetrazines to oxadiazole derivatives.

    PubMed

    Goswami, Soumyabrata; Jena, Himanshu Sekhar; Konar, Sanjit

    2014-07-21

    We present here a simple, milder, and environmentally benign heterogeneous catalytic method for the transformation of tetrazines to oxadiazole derivatives at room temperature (25 °C) using our earlier synthesized iron-squarate based 3D metal organic framework, [Fe3(OH)3(C4O4)(C4O4)0.5]n (FeSq-MOF).

  15. 40 CFR 721.10438 - Dialkyl hydroxybenzenealkanoic acid ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ester (generic). 721.10438 Section 721.10438 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10438 Dialkyl hydroxybenzenealkanoic acid ester (generic). (a) Chemical... as dialkyl hydroxybenzenealkanoic acid ester (PMN P-00-346) is subject to reporting under...

  16. 40 CFR 721.10438 - Dialkyl hydroxybenzenealkanoic acid ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ester (generic). 721.10438 Section 721.10438 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10438 Dialkyl hydroxybenzenealkanoic acid ester (generic). (a) Chemical... as dialkyl hydroxybenzenealkanoic acid ester (PMN P-00-346) is subject to reporting under...

  17. Biodegradation of the anionic surfactant dialkyl sulphosuccinate

    SciTech Connect

    Hales, S.G. . Port Sunlight Lab.)

    1993-10-01

    A range of Organization for Economic Cooperation and Development (OECD) guideline test systems was used to determine the extent and possible mechanisms of biodegradation of dialkyl sulphosuccinate (DASS, C[sub 6]/C[sub 8]). Primary biodegradation of DASS was virtually complete in OECD guideline tests and in simulations of activated sludge sewage treatment systems under both optimal and adverse conditions, and of an anaerobic digester. Ultimate biodegradation increased form about 50% in ready tests to 94% in more powerful inherent tests. [[sup 14]C]DASS was used to determine the fate of the surfactant in activated sludge and in surface waters. Mechanistic studies were performed to ascertain the biodegradative pathway of [[sup 14]C]DASS. A putative degradation pathway for DASS is proposed.

  18. Compression studies of face-to-face π-stacking interaction in sodium squarate salts: Na2C4O4 and Na2C4O4•3H2O

    NASA Astrophysics Data System (ADS)

    Li, Qian; Li, Shourui; Wang, Kai; Li, Wenbo; Liu, Jing; Liu, Bingbing; Zou, Guangtian; Zou, Bo

    2012-11-01

    High-pressure Raman scattering and synchrotron X-ray diffraction measurements of sodium squarate (Na2C4O4, SS) are performed in a diamond anvil cell. SS possesses a rare, but typical structure, which can show the effect of face-to-face π-stacking without interference of other interactions. At ˜11 GPa, it undergoes a phase transition, identified as a symmetry transformation from P21/c to P21. From high-pressure Raman patterns and the calculated model of SS, it can be proved that the phase transition results from the distorted squarate rings. We infer it is the enhancement of π-stacking that dominates the distortion. For comparison, high-pressure Raman spectra of sodium squarate trihydrate (Na2C4O4•3H2O, SST) are also investigated. The structure of SST is determined by both face-to-face π-stacking and hydrogen bonding. SST can be regarded as a deformation of SS. A phase transition, with the similar mechanism as SS, is observed at ˜10.3 GPa. Our results can be well supported by the previous high-pressure studies of ammonium squarate ((NH4)2C4O4, AS), and vice versa. High-pressure behaviors of the noncovalent interactions in SS, SST, and AS are compared to show the impacts of hydrogen bonding and the role of electrostatic interaction in releasing process.

  19. Safety Assessment of Dialkyl Malates as Used in Cosmetics.

    PubMed

    Becker, Lillian C; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2015-01-01

    The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the safety of 6 dialkyl malate compounds used in cosmetics. These ingredients function mostly as skin-conditioning agents-emollients. The Panel reviewed relevant animal and human data related to the ingredients along with a previous safety assessment of malic acid. The similar structure, properties, functions, and uses of these ingredients enabled grouping them and using the available toxicological data to assess the safety of the entire group. The Panel concluded that these dialkyl maleate compounds are safe in the present practices of use and concentration as given in this safety assessment.

  20. Microwave-assisted radical polymerization of dialkyl fumarates

    NASA Astrophysics Data System (ADS)

    Cortizo, M. Susana; Laurella, Sergio; Alessandrini, José Luis

    2007-07-01

    Free radical polymerization of dialkyl fumarates (R:isopropyl, cyclohexyl, 2-ethylhexyl, 2-phenylethyl) under microwave irradiation was investigated. The polymerizations were carried out at different powers of irradiation and initiator concentrations (benzoyl peroxide, BP) and the effect of the monomer structure on the conversion, average molecular weights and the polydispersity index ( Mw/ Mn) was analyzed. A significant enhancement of the rates of polymerization was found, as compared with those obtained under thermal conditions.

  1. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle...

  2. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle...

  3. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle...

  4. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle...

  5. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle...

  6. 40 CFR 721.10413 - Fluorinated dialkyl ketone (generic) (P-10-135).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) (P-10-135). 721.10413 Section 721.10413 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10413 Fluorinated dialkyl ketone (generic) (P-10-135). (a) Chemical... as fluorinated dialkyl ketone (PMN P-10-135) is subject to reporting under this section for...

  7. 40 CFR 721.10413 - Fluorinated dialkyl ketone (generic) (P-10-135).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) (P-10-135). 721.10413 Section 721.10413 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10413 Fluorinated dialkyl ketone (generic) (P-10-135). (a) Chemical... as fluorinated dialkyl ketone (PMN P-10-135) is subject to reporting under this section for...

  8. 40 CFR 721.10413 - Fluorinated dialkyl ketone (generic) (P-10-135).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) (P-10-135). 721.10413 Section 721.10413 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10413 Fluorinated dialkyl ketone (generic) (P-10-135). (a) Chemical... as fluorinated dialkyl ketone (PMN P-10-135) is subject to reporting under this section for...

  9. 75 FR 34045 - Sodium 1,4-Dialkyl Sulfosuccinates; Exemption from the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-16

    ... AGENCY 40 CFR Part 180 Sodium 1,4-Dialkyl Sulfosuccinates; Exemption from the Requirement of a Tolerance... an exemption from the requirement of a tolerance for residues of sodium 1,4-dialkyl sulfosuccinates including sodium 1,4-dihexyl sulfosuccinate (CAS Reg. No. 3006-15-3); sodium 1,4-diisobutyl...

  10. Methods of producing sulfate salts of cations from heteroatomic compounds and dialkyl sulfates and uses thereof

    DOEpatents

    Friesen, Cody A.; Wolfe, Derek; Johnson, Paul Bryan

    2015-09-29

    Methods of preparing sulfate salts of heteroatomic compounds using dialkyl sulfates as a primary reactant are disclosed. Also disclosed are methods of making ionic liquids from the sulfate salts of the heteroatomic compound, and electrochemical cells comprising the ionic liquids.

  11. Synthesis of sodium, potassium cesium, and ammonium O,O-dialkyl phosphoroselenothioates

    SciTech Connect

    Mel'nik, Ya.I.; Prots, D.I.; Kolodii, Ya.I.; Slavich, V.M.

    1986-10-20

    In search for a simpler method for the preparation of the title compounds and in continuation of the investigations on methods of synthesis and properties of organic derivatives of phosphorus seleno acids the authors have investigated the reactions of O,O-dialkyl hydrogen phosphorothioites with selenium and alkali-metal and ammonium carbonates, leading to the corresponding metal (ammonium) O,O-dialkyl phosphoroselenothioates.

  12. Synthesis and properties of N,N-dialkyl-P-phenylphosphonamidous iodides

    SciTech Connect

    Kovaleva, T.V.; Feshchenko, N.G.

    1987-01-20

    N,N-Dialkyl-P-phenylphosphonamidous iodides are formed in the reactions of phenylphosphonus diiodide with silylated secondary amines. N,N-Dialkyl-P-phenylphosphonamidous iodides react with electrophilic reagents (methyl iodide, benzenesulfonyl azide, and phenyl azide) by the usual schemes with the formation of alkylation and oxidative-imination products. Iodine catalyzes the disproportionation of morpholinophenylphosphinous iodide into dimorphomorpholinophenylphosphinous iodide with iodine are iododimorpholinophenylphosphonium triiodide and phenylphosphonous diiodide.

  13. Determination of 14 monoalkyl phosphates, dialkyl phosphates and dialkyl thiophosphates by LC-MS/MS in human urinary samples.

    PubMed

    Reemtsma, Thorsten; Lingott, Jana; Roegler, Stefanie

    2011-04-15

    Human urine was analyzed for nine dialkyl (DAP) and five monoalkyl phosphates (MAP) by LC-MS/MS. Some phosphoric acid esters are industrial chemicals and other hydrolysis products of trialkyl or triaryl phosphates, used as pesticides, flame retardants or plasticizers. Five MAP and two DAP were detected here for the first time in human urine. Monobutyl, diethyl, diphenyl and diethylhexyl phosphate were determined with median concentrations in the μg/L-range. The total urinary concentration of the 14 DAP and MAP summed up to a median of 20μg/L. Inclusion of MAP in future biomonitoring studies should provide a more comprehensive picture of the exposure of humans to organophosphorus compounds.

  14. Calibrating the glycerol dialkyl glycerol tetraether temperature signal in speleothems

    NASA Astrophysics Data System (ADS)

    Blyth, Alison J.; Schouten, Stefan

    2013-05-01

    Palaeotemperature proxies based on glycerol dialkyl glycerol tetraethers (GDGTs) lipids have been established for marine and lacustrine environments, but there has been relatively little study of their application in speleothems. In this study we analyse the GDGT content of 33 speleothem samples from 16 different sites around the globe, and test whether proxies based on isoprenoid tetraethers (TEX86) or branched tetraethers (MBT/CBT) are correlated with measured surface and cave mean annual air temperature (MAT). The results show that the TEX86 has a strong relationship with measured temperature (r2 = 0.78, standard error of the estimate 2.3 °C, when calibrated with surface MAT). Furthermore, the MBT/CBT also showed a significant relationship with temperature (r2 = 0.73, standard error of the estimate 2.7 °C, when calibrated with surface MAT). Some issues remain requiring future work, in particular the development of a larger calibration sample set with measured cave temperature data, and the investigation of controls other than temperature on GDGT distribution, but overall the results indicate that GDGT based proxies derived from speleothems may be highly viable new methods for reconstructing continental palaeotemperatures.

  15. 40 CFR 721.10664 - Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine (generic). 721.10664 Section 721.10664... Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine (generic)....

  16. 40 CFR 721.10664 - Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine (generic). 721.10664 Section 721.10664... Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine (generic)....

  17. Dialkyl Phosphate Urinary Metabolites and Chromosomal Abnormalities in Human Sperm

    PubMed Central

    Figueroa, Zaida I.; Young, Heather A.; Meeker, John D.; Martenies, Sheena E.; Barr, Dana Boyd; Gray, George; Perry, Melissa J.

    2015-01-01

    Background The past decade has seen numerous human health studies seeking to characterize the impacts of environmental exposures, such as organophosphate (OP) insecticides, on male reproduction. Despite an extensive literature on OP toxicology, many hormone-mediated effects on the testes are not well understood. Objectives This study investigated environmental exposures to OPs and their association with the frequency of sperm chromosomal abnormalities (i.e., disomy) among adult men. Methods Men (n=159) from a study assessing the impact of environmental exposures on male reproductive health were included in this investigation. Multi-probe fluorescence in situ hybridization (FISH) for chromosomes X, Y, and 18 was used to determine XX18, YY18, XY18 and total disomy in sperm nuclei. Urine was analyzed using gas chromatography coupled with mass spectrometry for concentrations of dialkyl phosphate (DAP) metabolites of OPs [dimethylphosphate (DMP); dimethylthiophosphate (DMTP); dimethyldithiophosphate (DMDTP); diethylphosphate (DEP); diethylthiophosphate (DETP); and diethyldithiophosphate (DEDTP)]. Poisson regression was used to model the association between OP exposures and disomy measures. Incidence rate ratios (IRRs) were calculated for each disomy type by exposure quartiles for most metabolites, controlling for age, race, BMI, smoking, specific gravity, total sperm concentration, motility, and morphology. Results A significant positive trend was seen for increasing IRRs by exposure quartiles of DMTP, DMDTP, DEP and DETP in XX18, YY18, XY18 and total disomy. A significant inverse association was observed between DMP and total disomy. Findings for total sum of DAP metabolites concealed individual associations as those results differed from the patterns observed for each individual metabolite. Dose-response relationships appeared nonmonotonic, with most of the increase in disomy rates occurring between the second and third exposure quartiles and without additional

  18. Base-catalyzed bicyclization of dialkyl glutaconates with cinnamoylacetamides: a synthetic strategy for isoquinolinedione derivatives.

    PubMed

    Li, Lei; Zhao, Yu-Long; Wang, He; Li, Yi-Jin; Xu, Xianxiu; Liu, Qun

    2014-06-21

    We report here that polysubstituted dihydroisoquinolones and isoquinolones can be constructed by the one-pot reaction of the readily available acyclic α,β-unsaturated carbonyl precursors and dialkyl glutaconates under mild basic conditions (1-45 min for the former vs. 1-6 h for the latter) via the domino process involving [3+3] annulation/intramolecular aza-cyclization.

  19. Oxygenase-Catalyzed Desymmetrization of N,N-Dialkyl-piperidine-4-carboxylic Acids**

    PubMed Central

    Rydzik, Anna M; Leung, Ivanhoe K H; Kochan, Grazyna T; McDonough, Michael A; Claridge, Timothy D W; Schofield, Christopher J

    2014-01-01

    γ-Butyrobetaine hydroxylase (BBOX) is a 2-oxoglutarate dependent oxygenase that catalyzes the final hydroxylation step in the biosynthesis of carnitine. BBOX was shown to catalyze the oxidative desymmetrization of achiral N,N-dialkyl piperidine-4-carboxylates to give products with two or three stereogenic centers. PMID:25164544

  20. 40 CFR 721.10342 - Quaternary ammonium compounds, fatty alkyl dialkyl hydroxide (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Quaternary ammonium compounds, fatty... Significant New Uses for Specific Chemical Substances § 721.10342 Quaternary ammonium compounds, fatty alkyl... chemical substance identified generically as quaternary ammonium compounds, fatty alkyl dialkyl...

  1. 40 CFR 721.10342 - Quaternary ammonium compounds, fatty alkyl dialkyl hydroxide (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Quaternary ammonium compounds, fatty... Significant New Uses for Specific Chemical Substances § 721.10342 Quaternary ammonium compounds, fatty alkyl... chemical substance identified generically as quaternary ammonium compounds, fatty alkyl dialkyl...

  2. 40 CFR 721.10342 - Quaternary ammonium compounds, fatty alkyl dialkyl hydroxide (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Quaternary ammonium compounds, fatty... Significant New Uses for Specific Chemical Substances § 721.10342 Quaternary ammonium compounds, fatty alkyl... chemical substance identified generically as quaternary ammonium compounds, fatty alkyl dialkyl...

  3. Distribution coefficients of purine alkaloids in water-ammonium sulfate-alkyl acetate-dialkyl phthalate systems

    NASA Astrophysics Data System (ADS)

    Korenman, Ya. I.; Krivosheeva, O. A.; Mokshina, N. Ya.

    2012-12-01

    The distribution of purine alkaloids (caffeine, theobromine, theophylline) was studied in the systems: alkyl acetates-dialkyl phtalate-salting-out agent (ammonium sulfate). The quantitative characteristics of the extraction-distribution coefficients ( D) and the degree of extraction ( R, %) are calculated. The relationships between the distribution coefficients of alkaloids and the length of the hydrocarbon radical in the molecule of alkyl acetate (dialkyl phtalate) are determined. The possibility of predicting the distribution coefficients is demonstrated.

  4. Atmospheric chemistry of toxic contaminants. 6. Nitrosamines: Dialkyl nitrosamines and nitrosomorpholine

    SciTech Connect

    Grosjean, D. )

    1991-05-01

    Detailed mechanisms are outlined for the reactions that contribute to in-situ formation and atmospheric removal of dimethylnitrosamine, diethylnitrosamine, methyl-ethylnitrosamine, and nitrosomorpholine. In-situ formation involves the rapid reaction of amines with the hydroxyl radical, leading to nitrosamines, nitramines, amides, and aldehydes. Nitrosamine photolysis accounts for their rapid daytime removal, leading to amino radicals whose atmospheric reactions are also discussed.

  5. Final safety assessment of thiodipropionic acid and its dialkyl esters as used in cosmetics.

    PubMed

    Diamante, Catherine; Fiume, Monice Zondlo; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Alan Andersen, F

    2010-07-01

    Dilauryl thiodipropionate (DLTDP), dicetyl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, and ditridecyl thiodipropionate are dialkyl esters of their respective alcohols and thiodipropionic acid (TDPA) used in cosmetics. Ingested DLTDP was excreted in the urine as TDPA. Single-dose acute oral and parenteral studies and subchronic and chronic repeated dose oral studies did not suggest significant toxicity. Neither DLTDP nor TDPA was irritating to animal skin or eyes and they were not sensitizers. TDPA was neither a teratogen nor a reproductive toxicant. Genotoxicity studies were negative for TDPA and DLTDP. Clinical testing demonstrated some evidence of irritation but no sensitization or photosensitization. The Cosmetic Ingredient Review Expert Panel considered that the data from DLTDP reasonably may be extrapolated to the other dialkyl esters and concluded that these ingredients were safe for use in cosmetic products that are formulated to be nonirritating.

  6. Mixed-valence states of 11, 1111-dialkyl- and 11, 1111-bis(methylbenzyl)biferrocenium triiodides

    NASA Astrophysics Data System (ADS)

    Nakashima, Satoru; Masuda, Yuichi; Motoyama, Izumi; Sano, Hirotoshi

    1988-02-01

    It was found that the packing of cations and anions influences the electronic structures of mixed-valence binuclear ferrocene derivatives. Temperature-dependence of the mixed-valence state of 11, 1111-diisobutylbiferrocenium triiodide was observed in a crystalline state, whereas only a trapped-valence state was found in a dispersed state. The packing effect was also observed for a series of 11, 1111-dialkyl- and 11, 1111-bis(methylbenzyl)biferrocenium triiodides by means of ESR spectroscopy.

  7. Dialkyl bisphosphonate platinum(II) complex as a potential drug for metastatic bone tumor.

    PubMed

    Nakatake, Hidetoshi; Ekimoto, Hisao; Aso, Mariko; Ogawa, Atsushi; Yamaguchi, Asami; Suemune, Hiroshi

    2011-01-01

    Bisphosphonates have high affinity for hydroxyapatite (HA), which is abundantly present in bone. Also, platinum complexes are known that have a wide spectrum of antitumor activities. The conjugate of bisphosphonate and a platinum complex might have HA affinity and antitumor activity, and become a drug for metastatic bone tumor. In this study, the authors synthesized platinum complexes that had dialkyl bisphosphonic acid as a ligand, and evaluated the possibility of the synthesized complexes as a drug for metastatic bone tumor. The synthesized dialkyl bisphosphonate platinum(II) complex was characterized, and its stability in an aqueous solution was also confirmed. The synthesized platinum complex showed higher HA affinity than other platinum complexes such as cisplatin and carboplatin in an experiment of adsorption to HA. In vitro, the platinum complex showed tumor growth inhibitory effect stronger than or equal to cisplatin, which is the most commonly used antitumor agent. Moreover, the platinum complex showed a bone absorption inhibitory effect on the osteoclast. These results suggest potential of dialkyl bisphosphonate platinum(II) complexes as a drug for metastatic bone tumor.

  8. Identification of O,O-dialkyl-S-methylphosphorodithioate residues in fish

    SciTech Connect

    Yurawecz, M.P.; Puma, B.J.

    1986-03-01

    O,O-Dialkyl-S-methylphosphorodithioates were found in Mississippi River buffalo fish caught near several chemical plants and oil refineries in Hartford and Wood River, IL. These chemicals, which have not been previously recognized as environmental or food contaminants, were identified and quantitated by a procedure similar to the AOAC multiresidue method for organochlorine and organophosphorus pesticides, using gas chromatography (GC) with flame photometric detection (FPD). The key to their identification was a GC/FPD retention time pattern that was virtually the same as that for the diazomethane reaction products of a commercial zinc dialkyl dithiophosphate motor oil additive. GC/mass spectrometry (MS) showed that the compound producing the largest GC/FPD peak contained butoxy groups. The identification of this compound as O,O-di(2-methylpropyl)-S-methyl-phosphorodithioate (Compound C) was confirmed by GC/MS analysis by comparison with the authentic material. The buffalo fish contained 0.15 ppm Compound C and 0.5 ppm total O,O-dialkyl-S-methylphosphorodithioates. Subsequent analyses of fish from other areas showed that these contaminants were not limited to the Hartford-Wood River area. Lower residue levels of Compound C, ranging from 0.01 to 0.05 ppm, were found in fish from the Mississippi River at Sauget, IL, and from the Delaware River and Newark Bay in NJ.

  9. Synthesis of Functionalized Dialkyl Ketones From Carboxylic Acid Derivatives and Alkyl Halides

    PubMed Central

    Wotal, Alexander C.; Weix, Daniel J.

    2012-01-01

    Unsymmetrical dialkyl ketones can be directly prepared by the nickel-catalyzed reductive coupling of carboxylic acid chlorides or (2-pyridyl)thioesters with alkyl iodides or benzylic chlorides. A wide variety of functional groups are tolerated by this process, including common nitrogen protecting groups and C-B bonds. Even hindered ketones flanked by tertiary and secondary centers can be formed. The mechanism is proposed to involve the reaction of a (L)Ni(alkyl)2 intermediate with the carboxylic acid derivative. PMID:22360350

  10. Sex pheromone for the brownbanded cockroach is an unusual dialkyl-substituted alpha-pyrone.

    PubMed Central

    Charlton, R E; Webster, F X; Zhang, A; Schal, C; Liang, D; Sreng, I; Roelofs, W L

    1993-01-01

    Female brownbanded cockroaches, Supella longipalpa, emit a sex pheromone that attracts males from a distance. This pheromone was isolated and identified as 5-(2,4-dimethylheptanyl)-3-methyl-2H-pyran-2-one (which we refer to as supellapyrone), and its structure was confirmed by synthesis. A racemic blend of the synthetic compound elicited behavioral and electrophysiological responses comparable to the natural pheromone across a range of doses. This compound is not only a very different type of cockroach pheromone but also makes up an additional class of natural products--namely, 3,5-dialkyl-substituted alpha-pyrones. PMID:11607437

  11. Sex pheromone for the brownbanded cockroach is an unusual dialkyl-substituted alpha-pyrone.

    PubMed

    Charlton, R E; Webster, F X; Zhang, A; Schal, C; Liang, D; Sreng, I; Roelofs, W L

    1993-11-01

    Female brownbanded cockroaches, Supella longipalpa, emit a sex pheromone that attracts males from a distance. This pheromone was isolated and identified as 5-(2,4-dimethylheptanyl)-3-methyl-2H-pyran-2-one (which we refer to as supellapyrone), and its structure was confirmed by synthesis. A racemic blend of the synthetic compound elicited behavioral and electrophysiological responses comparable to the natural pheromone across a range of doses. This compound is not only a very different type of cockroach pheromone but also makes up an additional class of natural products--namely, 3,5-dialkyl-substituted alpha-pyrones.

  12. From ether to acid: A plausible degradation pathway of glycerol dialkyl glycerol tetraethers

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Lei; Birgel, Daniel; Elling, Felix J.; Sutton, Paul A.; Lipp, Julius S.; Zhu, Rong; Zhang, Chuanlun; Könneke, Martin; Peckmann, Jörn; Rowland, Steven J.; Summons, Roger E.; Hinrichs, Kai-Uwe

    2016-06-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are ubiquitous microbial lipids with extensive demonstrated and potential roles as paleoenvironmental proxies. Despite the great attention they receive, comparatively little is known regarding their diagenetic fate. Putative degradation products of GDGTs, identified as hydroxyl and carboxyl derivatives, were detected in lipid extracts of marine sediment, seep carbonate, hot spring sediment and cells of the marine thaumarchaeon Nitrosopumilus maritimus. The distribution of GDGT degradation products in environmental samples suggests that both biotic and abiotic processes act as sinks for GDGTs. More than a hundred newly recognized degradation products afford a view of the stepwise degradation of GDGT via (1) ether bond hydrolysis yielding hydroxyl isoprenoids, namely, GDGTol (glycerol dialkyl glycerol triether alcohol), GMGD (glycerol monobiphytanyl glycerol diether), GDD (glycerol dibiphytanol diether), GMM (glycerol monobiphytanol monoether) and bpdiol (biphytanic diol); (2) oxidation of isoprenoidal alcohols into corresponding carboxyl derivatives and (3) chain shortening to yield C39 and smaller isoprenoids. This plausible GDGT degradation pathway from glycerol ethers to isoprenoidal fatty acids provides the link to commonly detected head-to-head linked long chain isoprenoidal hydrocarbons in petroleum and sediment samples. The problematic C80 to C82 tetraacids that cause naphthenate deposits in some oil production facilities can be generated from H-shaped glycerol monoalkyl glycerol tetraethers (GMGTs) following the same process, as indicated by the distribution of related derivatives in hydrothermally influenced sediments.

  13. Beyond paraquats: dialkyl 3,3'- and 3,4'-bipyridinium amphiphiles as antibacterial agents.

    PubMed

    Ator, Laura E; Jennings, Megan C; McGettigan, Amanda R; Paul, Jared J; Wuest, William M; Minbiole, Kevin P C

    2014-08-15

    Dialkyl 4,4'-bipyridinium compounds, known as 'paraquats' (PQs), have a long history of use as herbicides, as redox indicators, and more recently as potent antibacterial agents. However, due to their ability to form reactive oxygen species (ROS) in vivo, PQs are also known to be toxic. We proposed that altering the electrochemical properties of PQ, specifically by preparing isomeric bipyridinium structures with 3,3'- and 3,4'-substitution of the nitrogen heteroatoms on the biaryl core, would maintain antibacterial activity, yet decrease toxicity. We have thus prepared a series of 17 amphiphiles, dubbed 'metaquat' (MQ) and 'parametaquat' (PMQ), respectively, and investigated their antibacterial and electrochemical properties. Optimal inhibition of bacterial growth was observed in symmetric, biscationic structures; minimum inhibitory concentration (MIC) values measured as low as 0.5 μM against both Gram-positive and Gram-negative bacteria for the compound PMQ-11,11. Electrochemical analysis demonstrated the redox properties of the dialkyl 3,3'- and 3,4'-bipyridinium amphiphiles to be distinct from those of the 4,4'-bipyridinium isomer. Thus MQ and PMQ amphiphiles maintain the strong antibacterial activity of the PQ isomers, but show promise for reduced ROS toxicity.

  14. Evaporation dynamics of microdroplets on self-assembled monolayers of dialkyl disulfides.

    PubMed

    Li, Guangfen; Flores, Susana Moreno; Vavilala, Chandrasekhar; Schmittel, Michael; Graf, Karlheinz

    2009-12-01

    We present a study of the static wettability and evaporation dynamics of sessile microdroplets of water on self-assembled monolayers (SAMs) prepared with unsymmetric dialkyl disulfides CH(3)-(CH(2))(11+m)-S-S-(CH(2))(11)-OH (m = 0, +/- 2, +/- 4, +/- 6) on gold-covered mica. The advancing and receding contact angles decrease linearly with increasing hydrophilicity of the SAM. The latter was changed either via the molar ratio or via the chain length of the hydroxyl-terminated alkyl chains in the monolayer. In contrast to SAMs made of thiols, the contact angle hysteresis was 10 degrees for all disulfides, irrespective of their chain lengths. During evaporation of single droplets, a transition from pinning to constant contact angle mode was observed. The transition time between the modes increases with the surface hydrophilicity, leading to longer pinning. This way, the time for complete droplet evaporation decreases by approximately 30% owing to the fact that during pinning the overall droplet area stays large for a longer time. For single droplets the measured total evaporation times agree well with the calculated ones, showing the validity of the standard evaporation model for both evaporation modes. In contrast to the results for single droplets, many droplets with different initial volumes show a power-law dependence on the total evaporation time with an exponent different from 1.5 as expected from the standard model. For disulfides with m not equal 0, the exponent is in the range of 1.40-1.47 increasing with the surface hydrophilicity. For the SAMs with m = 0 the exponent increases up to 1.61 for the most hydrophilic surface. We explain this deviation from the standard evaporation model with the presence of a liquid precursor film around the droplet, which either enhances or decelerates evaporation. Our results suggest that SAMs of dialkyl disulfides offer the possibility to tune the wettability of gold surfaces in a more controlled way than thiols do.

  15. Asymmetric Friedel-Crafts alkylations of indoles with dialkyl 3-oxoprop-1-enylphosphonates: organocatalytic enantioselective synthesis of alpha-indolyl phosphonates.

    PubMed

    Guo, Ying-Cen; Li, Dong-Ping; Li, Yu-Ling; Wang, Hong-Mei; Xiao, Wen-Jing

    2009-08-01

    Organocatalytic enantioselective synthesis of alpha-indolyl phosphonates has been successfully carried out via asymmetric Friedel-Crafts alkylation of substituted indoles with (E)-dialkyl 3-oxoprop-1-enylphosphonates in 48-82% yield and 73-96% ee.

  16. Monolayer Films Prepared by the Spontaneous Self-Assembly of Symmetrical and Unsymmetrical Dialkyl Sulfides from Solution Onto Gold Substrates: Structure, Properties, and Reactivity of Constituent Functional Groups.

    DTIC Science & Technology

    1987-10-01

    adsorption of dialkyl sulfides from alcohol solution onto supported evaporated gold films and examines relations between the molecular structure of the...derivatives. The particular hypothesis used as the basis for this work is summarized in Figure 1. Adsorption of an unsymmetrical dialkyl sulfide, CH3 (CH2...minutes to hours. The adsorption process, and the characteristics of the resulting films, were followed using a number of techniques, of which

  17. Mass spectral studies of a series of N,N-dialkyl aminoethyl-2-chlorides and trimethyl silyl ethers of N,N-dialkyl aminoethane-2-ols under electron impact conditions.

    PubMed

    Reddy, T Jagadeshwar; Prabhakar, S; Ravi Kumar, M; Saradhi, U V R Vijaya; Vairamani, M

    2006-01-01

    The electron impact (EI) mass spectra of a series of N,N-dialkyl-aminoethyl-2-chlorides, N(R(1))(R(2))-CH(2)-CH(2)Cl and trimethylsilyl ethers of N,N-dialkyl aminoethane-2-ols, N(R(1))(R(2))-CH(2)-CH(2)-O-Si(CH(3))(3), where R(1) and R(2) = methyl, ethyl, propyl and isopropyl, which are precursors of VX type of compounds, are studied. All the compounds (1-20) show abundant molecular ions, in addition to a weak [M - H](+) ion, except the N,N-diisopropyl group containing compounds (8 and 18). A general EI fragmentation pattern for the above two series of compounds is discussed. The observed fragment ions are due to simple homolytic cleavages, and they are distinct to allow the identification of the compounds unequivocally including those of isomeric compounds. The primary fragmentation of compounds 1-20 is beta-cleavage, i.e. homolytic cleavage of C-C bond, which is linked to the nitrogen atom. Three types of beta-cleavages are possible for these compounds, in which the abundance of beta-cleavage product ions is found to depend on the size and structure of the alkyl group attached to nitrogen. The alpha-cleavage fragment ions are found only for N,N-dialkyl aminoethyl-2-chlorides but are absent in the corresponding trimethylsilyl ethers of N,N-dialkyl aminoethane-2-ols. The retention indices are calculated for all the studied compounds (1-20) and are in the ranges of 750.38-1079.24 for 1-10 and 905.23-1190.25 for 11-20.

  18. Mixed aggregate formation in gemini surfactant/1,2-dialkyl-sn-glycero-3-phosphoethanolamine systems.

    PubMed

    Akbar, Javed; Tavakoli, Naser; Marangoni, D Gerrard; Wettig, Shawn D

    2012-07-01

    An evaluation of the physical interactions between gemini surfactants, DNA, and 1,2-dialkyl-sn-glycero-3-phosphoethanolamine helper lipid is presented in this work. Complexation between gemini surfactants and DNA was first investigated using surface tensiometry where the surface tension profiles obtained were found to be consistent with those typically observed for mixed surfactant-polymer systems; that is, there is a synergistic lowering of the surface tension, followed by a first (CAC) and second (CMC) break point in the plot. The surfactant alkyl tail length was observed to exhibit a significant effect on the CAC, thus demonstrating the importance of hydrophobic interactions during complexation between gemini surfactants and DNA. The second study presented is an investigation of the mixing interactions between gemini surfactants and DOPE using Clint's, Rubingh's, and Motomura's theories for mixed micellar formation. The mixing interactions between the 16-3-16/16-7-16/16-12-16/16-7NH-16 gemini surfactants and DOPE were observed to be antagonistic, where the strength of antagonism was found to be dependent upon the gemini surfactant spacer group and the solution composition.

  19. Toxicological properties of trialkyl phosphorothioate and dialkyl alkyl- and arylphosphonothioate esters.

    PubMed

    Fukuto, T R

    1983-01-01

    Impurities such as O,S,S-trimethyl phosphorodithioate (TMPD) and the S-methyl isomer of malathion (isomalathion) strongly potentiated the mammalian toxicity of malathion. In contrast, impurities present in the phosphoramidothioate insecticide acephate had an antagonizing effect on its mammalian toxicity. The potentiation of the toxicity of malathion was attributed to inhibition of mammalian liver and serum carboxylesterase. O,O,S-Trimethyl phosphorothioate (TMP), another impurity present in technical malathion and in other organophosphorus insecticides, proved to be highly toxic. Rats given a single oral dose of TMP at a level as low as 20 mg/kg died over a period of three weeks, with death occurring with non-cholinergic signs of poisoning. TMPD also caused similar delayed death in rats. O,O,O-Trimethyl phosphorothioate (TMP=S), also another impurity in technical malathion and a structural isomer of TMP, was a potent antagonist to the delayed toxicity of TMP. Examination of a number of related trialkyl phosphorothioate and dialkyl alkylphosphonothioate esters revealed several of these compounds to be highly toxic to rats.

  20. The Holocene Records of Glycerol Dialkyl Glycerol Tetraethers From the Northern Chukchi Sea

    NASA Astrophysics Data System (ADS)

    Park, Y.; Yamamoto, M.; Nam, S.; Polyak, L. V.

    2013-12-01

    We analyzed glycerol dialkyl glycerol tetraethers (GDGTs) in Cores HOTRAX 05-01 JPC5 and JPC 8, and ARA02B 01-GC in the northern Chukchi Sea. All of the three cores showed a similar changing pattern in GDGT composition during the Holocene. In the beginning of early Holocene, both isoprenoid and branched GDGT concentrations were low, and BIT and CBT were relatively high. The similar composition is found in modern sediments from the western Arctic Ocean north of 75°N, suggesting that the northern Chukchi Sea was covered by perennial sea ice. GDGT concentration increased, and BIT and CBT decreased during the early Holocene and reached the same level as those in modern sediments at 8 ka. TEX86 and CBT/MBT indices showed millennial-scale variation. We interpret that these proxies did not simply indicate temperatures but were affected by the relative contribution of different sediment sources. Millennial-scale variability likely reflected changes in sediment transport in the northern Chukchi Sea.

  1. On the nature of the fluorenone-based emission in oxidized poly(dialkyl-fluorene)s

    NASA Astrophysics Data System (ADS)

    Ferenczi, T. A. M.; Sims, M.; Bradley, D. D. C.

    2008-01-01

    This study examines the underlying nature of the green emission band observed as a result of oxidation in dialkyl-fluorene polymers. Specifically, we set out to further determine whether an inter- (excimeric) or intra-molecular fluorenone-based excited state is involved. The emission properties of poly(9,9-dihexylfluorene) dispersed at low concentration in a solid polystyrene matrix are carefully explored. In situ, time-resolved photoluminescence measurements are made during photo-oxidation of the blend and during subsequent exposure to an atmosphere saturated with the vapour of a good solvent. The polystyrene matrix suppresses the appearance of the green emission band during oxidation but the subsequent solvent vapour exposure then activates it. The same effect (activation of the green emission) can be achieved by thermally annealing the matrix above its glass transition temperature. Moreover, the activation of the green emission can be reversed by dissolving the film and re-casting. This behaviour is attributed to controlling the phase structure of the polyfluorene/polystyrene blend and is considered strong evidence for an origin of the green band emission in the formation of excimer-like states between co-facially arranged fluorenone moieties. The photoluminescence behaviour of 9-fluorenone and fluorene molecular mixtures in solution is also studied. This model system allows analysis of the green emission band independent of relative intra- and inter-molecular energy transfer effects since this system is affected only by inter-molecular energy transfer. These results provide further evidence for an excimeric origin of the green emission.

  2. Concentrations of dialkyl phosphate metabolites of organophosphorus pesticides in the U.S. population.

    PubMed Central

    Barr, Dana B; Bravo, Roberto; Weerasekera, Gayanga; Caltabiano, Lisa M; Whitehead, Ralph D; Olsson, Anders O; Caudill, Samuel P; Schober, Susan E; Pirkle, James L; Sampson, Eric J; Jackson, Richard J; Needham, Larry L

    2004-01-01

    We report population-based concentrations, stratified by age, sex, and racial/ethnic groups, of dialkyl phosphate (DAP) metabolites of multiple organophosphorus pesticides. We measured dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate (DEP), diethylthiophosphate (DETP), and diethyldithiophosphate (DEDTP) concentrations in 1,949 urine samples collected in U.S. residents 6-59 years of age during 1999 and 2000 as a part of the ongoing National Health and Nutrition Examination Survey (NHANES). We detected each DAP metabolite in more than 50% of the samples, with DEP being detected most frequently (71%) at a limit of detection of 0.2 microg/L. The geometric means for the metabolites detected in more than 60% of the samples were 1.85 microg/L for DMTP and 1.04 microg/L for DEP. The 95th percentiles for each metabolite were DMP, 13 microg/L; DMTP, 46 microg/L; DMDTP, 19 micro g/L; DEP, 13 microg/L; DETP, 2.2 microg/L; and DEDTP, 0.87 microg/L. We determined the molar sums of the dimethyl-containing and diethyl-containing metabolites; their geometric mean concentrations were 49.4 and 10.5 nmol/L, respectively, and their 95th percentiles were 583 and 108 nmol/L, respectively. These data are also presented as creatinine-adjusted concentrations. Multivariate analyses showed concentrations of DAPs in children 6-11 years of age that were consistently significantly higher than in adults and often higher than in adolescents. Although the concentrations between sexes and among racial/ethnic groups varied, no significant differences were observed. These data will be important in evaluating the impact of organophosphorus pesticide exposure in the U.S. population and the effectiveness of regulatory actions. PMID:14754573

  3. Archaeal and bacterial glycerol dialkyl glycerol tetraether lipids in hot springs of yellowstone national park.

    PubMed

    Schouten, Stefan; van der Meer, Marcel T J; Hopmans, Ellen C; Rijpstra, W Irene C; Reysenbach, Anna-Louise; Ward, David M; Sinninghe Damsté, Jaap S

    2007-10-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are core membrane lipids originally thought to be produced mainly by (hyper)thermophilic archaea. Environmental screening of low-temperature environments showed, however, the abundant presence of structurally diverse GDGTs from both bacterial and archaeal sources. In this study, we examined the occurrences and distribution of GDGTs in hot spring environments in Yellowstone National Park with high temperatures (47 to 83 degrees C) and mostly neutral to alkaline pHs. GDGTs with 0 to 4 cyclopentane moieties were dominant in all samples and are likely derived from both (hyper)thermophilic Crenarchaeota and Euryarchaeota. GDGTs with 4 to 8 cyclopentane moieties, likely derived from the crenarchaeotal order Sulfolobales and the euryarchaeotal order Thermoplasmatales, are usually present in much lower abundance, consistent with the relatively high pH values of the hot springs. The relative abundances of cyclopentane-containing GDGTs did not correlate with in situ temperature and pH, suggesting that other environmental and possibly genetic factors play a role as well. Crenarchaeol, a biomarker thought to be specific for nonthermophilic group I Crenarchaeota, was also found in most hot springs, though in relatively low concentrations, i.e., <5% of total GDGTs. Its abundance did not correlate with temperature, as has been reported previously. Instead, the cooccurrence of relatively abundant nonisoprenoid GDGTs thought to be derived from soil bacteria suggests a predominantly allochthonous source for crenarchaeol in these hot spring environments. Finally, the distribution of bacterial branched GDGTs suggests that they may be derived from the geothermally heated soils surrounding the hot springs.

  4. Source, settling and degradation of branched glycerol dialkyl glycerol tetraethers in the marine water column

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masanobu; Shimamoto, Akifumi; Fukuhara, Tatsuo; Tanaka, Yuichiro

    2016-10-01

    Branched glycerol dialkyl glycerol tetraethers (branched GDGTs) are commonly found in distal marine sediments. However, their presence in the water column, source and delivery process are not fully understood. In this study, we examined seasonal and depth variation in the flux of branched GDGTs in sinking particles and underlying sediment at 39°N, 147°E in the mid-latitude NW Pacific from November 1997 to August 1999. Branched GDGTs showed synchronous variation in their sinking flux at different depths, and the variation was similar to that of lithogenic material of eolian dust origin. Their degrees of cyclization and methylation were nearly constant and bear some resemblance to those of alkaline soils. This suggests that westerly winds transport branched GDGTs to the study site via the atmosphere from continental Asia. The sinking flux of branched GDGTs was higher in 1999 than in 1998, presumably reflecting changes in the migration path of Asian dust in response to the El Niño-Southern Oscillation. Synchronous variation in branched GDGT concentrations at different depths implies rapid vertical transport of branched GDGTs to deep water with a sinking velocity exceeding 260 m d-1. The sinking flux of the branched GDGTs decreased with increasing depth, but the rate of decrease was much smaller than those of other compounds. The preservation efficiency of branched GDGTs was 3.5-6.4% of surface inputs at the water-sediment interface, which is much higher than those of isoprenoid GDGTs (1.0-1.3%) and other compounds. The branched and isoprenoid tetraether (BIT) index values were extremely low (i.e. <0.0015) in comparison with any other studies so far. The BIT values in the surface sediment were five times higher than those in sinking particles, which is attributed to the preferential preservation of branched GDGTs in oxic environments.

  5. Molecular dynamics simulation study of the effect of glycerol dialkyl glycerol tetraether hydroxylation on membrane thermostability.

    PubMed

    Huguet, Carme; Fietz, Susanne; Rosell-Melé, Antoni; Daura, Xavier; Costenaro, Lionel

    2017-02-16

    Archaeal tetraether membrane lipids span the whole membrane width and present two C40 isoprenoid chains bound by two glycerol groups (or one glycerol and calditol). These lipids confer stability and maintain the membrane fluidity in mesophile to extremophile environments, making them very attractive for biotechnological applications. The isoprenoid lipid composition in archaeal membranes varies with temperature, which has placed these lipids in the focus of paleo-climatological studies for over a decade. Non-hydroxylated isoprenoid archaeal lipids are typically used as paleo-thermometry proxies, but recently identified hydroxylated (OH) derivatives have also been proposed as temperature proxies. The relative abundance of hydroxylated lipids increases at lower temperatures, but the physiological function of the OH moiety remains unknown. Here we present molecular dynamics simulations of membranes formed by the acyclic glycerol-dialkyl-glycerol-tetraether caldarchaeol (GDGT-0), the most widespread archaeal core lipid, and its mono-hydroxylated variant (OH-GDGT-0) to better understand the physico-chemical properties conferred to the membrane by this additional moiety. The molecular dynamics simulations indicate that the additional OH group forms hydrogen bonds mainly with the sugar moieties of neighbouring lipids and with water molecules, effectively increasing the size of the polar headgroups. The hydroxylation also introduces local disorder that propagates along the entire alkyl chains, resulting in a slightly more fluid membrane. These changes would help to maintain trans-membrane transport in cold environments, explaining why the relative abundance of hydroxylated Archaea lipids increases at lower temperatures. The in silico approach aids to understand the underlying physiological mechanisms behind the hydroxylated lipid based paleo-thermometer recently proposed.

  6. In situ production of branched glycerol dialkyl glycerol tetraethers in a great basin hot spring (USA)

    PubMed Central

    Zhang, Chuanlun L.; Wang, Jinxiang; Dodsworth, Jeremy A.; Williams, Amanda J.; Zhu, Chun; Hinrichs, Kai-Uwe; Zheng, Fengfeng; Hedlund, Brian P.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are predominantly found in soils and peat bogs. In this study, we analyzed core (C)-bGDGTs after hydrolysis of polar fractions using liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry and analyzed intact P-bGDGTs using total lipid extract (TLE) without hydrolysis by liquid chromatography-electrospray ionization-multiple stage mass spectrometry. Our results show multiple lines of evidence for the production of bGDGTs in sediments and cellulolytic enrichments in a hot spring (62–86°C) in the Great Basin (USA). First, in situ cellulolytic enrichment led to an increase in the relative abundance of hydrolysis-derived P-bGDGTs over their C-bGDGT counterparts. Second, the hydrolysis-derived P- and C-bGDGT profiles in the hot spring were different from those of the surrounding soil samples; in particular, a monoglycosidic bGDGT Ib containing 13,16-dimethyloctacosane and one cyclopentane moiety was detected in the TLE but it was undetectable in surrounding soil samples even after sample enrichments. Third, previously published 16S rRNA gene pyrotag analysis from the same lignocellulose samples demonstrated the enrichment of thermophiles, rather than mesophiles, and total bGDGT abundance in cellulolytic enrichments correlated with the relative abundance of 16S rRNA gene pyrotags from thermophilic bacteria in the phyla Bacteroidetes, Dictyoglomi, EM3, and OP9 (“Atribacteria”). These observations conclusively demonstrate the production of bGDGTs in this hot spring; however, the identity of organisms that produce bGDGTs in the geothermal environment remains unclear. PMID:23847605

  7. Plio-Pleistocene Temperature Variability in the Terrestrial Arctic: Insights from Branched Glycerol Dialkyl Glycerol Tetraethers

    NASA Astrophysics Data System (ADS)

    Castañeda, I. S.; Salacup, J.; de Wet, G.; Habicht, M. H.; Keisling, B. A.; Phu, V.; Johnson, J.; Lukas, S.; Lyons, N.; Brigham-Grette, J.

    2014-12-01

    Drill coring at Lake El'gygytgyn (Far East Russia) in 2009 retrieved a 3.6 Ma long sediment core, which is presently the oldest continuous sedimentary record available from the terrestrial Arctic. This unique Plio-Pleistocene record allows for the response of the Arctic to global climate events under a variety of different boundary conditions to be examined. Here we present results of ongoing organic geochemical analyses of Lake El'gygytgyn sediments focusing on the mid-Pliocene warm period, the Plio-Pleistocene transition, the mid-Brunhes transition, and warm Pleistocene interglacial periods including Marine Isotope Stages (MIS) 5, 9, 11, 19 and 31. Despite the ultra-oligotrophic nature of Lake El'gygytgyn and the generally low sedimentary total organic carbon (TOC) content, we find abundant branched glycerol dialkyl glycerol tetraethers (brGDGTs) throughout the entire record and use the methylation and cyclization indices of branched tetraethers (MBT and CBT, respectively) to reconstruct past temperature (Weijers et al., 2007). We hypothesize that the majority of brGDGTs are produced in the lake during the brief summer period of ice free conditions and that MBT/CBT likely reflects a warm season temperature. Trends noted in the MBT/CBT record are in close agreement with pollen-based temperature estimates throughout the entire core. For example, we note a dramatic ~6°C cooling associated with the mid-Pliocene M2 event and thus far MIS 31 has emerged as the warmest period at Lake El'gygytgyn during the past ~ 1 Ma, corroborating the pollen data. Interestingly, a number of abrupt and relatively short-lived cooling events of 2 to 4°C are noted within several of the particularly warm interglacial periods (e.g. MIS 5e, MIS 11 and MIS 31) and are the subject of ongoing investigation. Overall, application of the MBT/CBT paleothermometer to Lake El'gygytgyn sediments is a highly promising technique for generating a Plio-Pleistocene temperature record from the continental

  8. Double nucleophilic 1,2-addition of silylated dialkyl phosphites to 4-phosphono-1-aza-1,3-dienes: synthesis of gamma-phosphono-alpha-aminobisphosphonates.

    PubMed

    Masschelein, Kurt G R; Stevens, Christian V

    2007-11-23

    gamma-Phosphono-alpha-aminobisphosphonates were synthesized from a new class of 4-phosphono-1-aza-1,3-dienes by the addition of dialkyl trimethylsilyl phosphites to these azadienes in the presence of acid. Depending on the steric demand of the group on nitrogen, double 1,2-addition or tandem 1,4-1,2-addition occurred.

  9. Inverse-Micelle-Encapsulated Water-Enabled Bond Breaking of Dialkyl Diselenide/Disulfide: A Critical Step for Synthesizing High- Quality Gold Nanoparticles

    SciTech Connect

    Zaluzhna, Oksana; Li, Ying; Allison, Thomas C.; Tong, Yu ye J.

    2012-10-09

    Inverse-micelle-encapsulated water formed in the two-phase Brust-Schiffrin method (BSM) synthesis of Au nanoparticles (NPs) is identified as essential for dialkyl diselenide/disulfide to react with the Au(III) complex in which the Se-Se/S-S bond is broken, leading to formation of higher-quality Au NPs.

  10. Glycerol dialkyl glycerol tetraethers preserved in stalagmites: a new continental palaeothermometer

    NASA Astrophysics Data System (ADS)

    Blyth, A. J.; Schouten, S.

    2010-12-01

    The ability to recover reliable temperature records is central to palaeoclimatic research, informing our understanding of the past and our models of the future. However, there is a need for new quantitative terrestrial temperature proxies. Here we present a novel palaeothermometer, combining molecular temperature proxies with the strong dating control and established environmental records provided by stalagmites. The results show good correlations between known and calculated temperatures, suggesting that the approach has considerable potential as a climatic proxy. Glycerol dialkyl glycerol tetraethers (GDGTs) are microbial membrane lipids, which vary in structure with temperature and pH [1]. In the terrestrial realm, the focus is on bacterially derived GDGTs, which have been used to measure terrestrial organic matter input to aquatic deposits via the BIT index [2], and developed into a temperature related index (MBT/CBT) in soils and near-shore marine sediments (MBT/CBT), based upon the degree of branching and cyclicisation of the carbon skeleton [3]. Stalagmites form an ideal archive for terrestrial climate records, as they are stable, can be easily dated, and contain a number of environmental proxies (stable isotopes, trace elements, organic matter etc). Attempts have been made to develop inorganic temperature proxies in stalagmites, most recently using isotopic analysis of fluid inclusions. However, the use of organic temperature proxies in this context is largely unstudied. Thirty-eight stalagmite or stalactite samples from twenty-one sites around the world were analysed for their GDGT content. Calcite samples were cleaned and decalcified with HCl, and lipids extracted into dichloromethane via liquid-liquid extraction. Each extract was then prepared and analysed via HPLC-MS following Weijers et al. [3]. The results show low but usable levels of GDGTs in all but one sample. Peak size measurements were made for all recognised compounds associated with BIT and

  11. Dynamic kinetic resolution via asymmetric conjugate reduction: enantio- and diastereoselective synthesis of 2,4-dialkyl cyclopentanones.

    PubMed

    Jurkauskas, Valdas; Buchwald, Stephen L

    2002-03-27

    Herein, we report the kinetic and the dynamic kinetic resolutions of racemic 3,5-dialkyl-2-cyclopenten-1-ones. Kinetic resolution, with good selectivity factors (25-52), was achieved by conjugate reduction with catalytic CuCl/NaOt-Bu/(S)-p-tol-BINAP and stoichiometric quantities of poly(methylhydrosiloxane) (PMHS). When stoichiometric amounts of NaOt-Bu and t-BuOH were included in the reaction mixture, rapid racemization of the starting material occurred allowing for the dynamic kinetic resolution of the cyclopentenone substrates. In this process, chiral 2,4-dialkylcyclopentanones were isolated with high stereoselectivity (ee > or = 91%, dr > or = 90:10) and in high yield (> or =89%).

  12. Regio- and Stereochemical Control in Ocimene Polymerization by Half-Sandwich Rare-Earth Metal Dialkyl Complexes.

    PubMed

    Peng, Deqian; Du, Gaixia; Zhang, Pengfei; Yao, Bo; Li, Xiaofang; Zhang, Shaowen

    2016-06-01

    The polymerization of ocimene has been first achieved by half-sandwich rare-earth metal dialkyl complexes in combination with activator and Al(i) Bu3 . The regio- and stereoselectivity in the ocimene polymerization can be controlled by tuning the cyclopentadienyl ligand and the central metal of the complex. The chiral cyclopentadienyl-ligated Sc complex 1 prepares syndiotactic cis-1,4-polyocimene (cis-1,4-selectivity up to 100%, rrrr = 100%), while the corresponding Lu, Y, and Dy complexes 2-4 and the achiral pentamethylcyclopentadienyl Sc, Lu, and Y complexes 5-7 afford isotactic trans-1,2-polyocimenes (trans-1,2-selectivity up to 100%, mm = 100%).

  13. Biophysical chemistry.

    PubMed

    Häussinger, Daniel; Pfohl, Thomas

    2010-01-01

    Biophysical chemistry at the Department of Chemistry, University of Basel, covers the NMR analysis of protein-protein interaction using paramagnetic tags and sophisticated microscopy techniques investigating the dynamics of biological matter.

  14. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Presents background information, laboratory procedures, classroom materials/activities, and chemistry experiments. Topics include sublimation, electronegativity, electrolysis, experimental aspects of strontianite, halide test, evaluation of present and future computer programs in chemistry, formula building, care of glass/saturated calomel…

  15. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1976

    1976-01-01

    Described are eight chemistry experiments and demonstrations applicable to introductory chemistry courses. Activities include: measure of lattice enthalpy, Le Chatelier's principle, decarboxylation of soap, use of pocket calculators in pH measurement, and making nylon. (SL)

  16. Chemistry Dashboard

    EPA Pesticide Factsheets

    The Chemistry Dashboard is part of a suite of dashboards developed by EPA to help evaluate the safety of chemicals. The Chemistry Dashboard provides access to a variety of information on over 700,000 chemicals currently in use.

  17. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Thirteen ideas are presented that may be of use to chemistry teachers. Topics covered include vitamin C, industrial chemistry, electrical conductivity, electrolysis, alkali metals, vibration modes infra-red, dynamic equilibrium, and some new demonstrations in gaseous combinations. (PS)

  18. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Presents background information, laboratory procedures, classroom materials/activities, and experiments for chemistry. Topics include superheavy elements, polarizing power and chemistry of alkali metals, particulate carbon from combustion, tips for the chemistry laboratory, interesting/colorful experiments, behavior of bismuth (III) iodine, and…

  19. CLUSTER CHEMISTRY

    SciTech Connect

    Muetterties, Earl L.

    1980-05-01

    Metal cluster chemistry is one of the most rapidly developing areas of inorganic and organometallic chemistry. Prior to 1960 only a few metal clusters were well characterized. However, shortly after the early development of boron cluster chemistry, the field of metal cluster chemistry began to grow at a very rapid rate and a structural and a qualitative theoretical understanding of clusters came quickly. Analyzed here is the chemistry and the general significance of clusters with particular emphasis on the cluster research within my group. The importance of coordinately unsaturated, very reactive metal clusters is the major subject of discussion.

  20. Forensic chemistry.

    PubMed

    Bell, Suzanne

    2009-01-01

    Forensic chemistry is unique among chemical sciences in that its research, practice, and presentation must meet the needs of both the scientific and the legal communities. As such, forensic chemistry research is applied and derivative by nature and design, and it emphasizes metrology (the science of measurement) and validation. Forensic chemistry has moved away from its analytical roots and is incorporating a broader spectrum of chemical sciences. Existing forensic practices are being revisited as the purview of forensic chemistry extends outward from drug analysis and toxicology into such diverse areas as combustion chemistry, materials science, and pattern evidence.

  1. Synthesis of 3-iodoindoles by the Pd/Cu-catalyzed coupling of N,N-dialkyl-2-iodoanilines and terminal acetylenes, followed by electrophilic cyclization.

    PubMed

    Yue, Dawei; Yao, Tuanli; Larock, Richard C

    2006-01-06

    [reaction: see text] 3-Iodoindoles have been prepared in excellent yields by coupling terminal acetylenes with N,N-dialkyl-o-iodoanilines in the presence of a Pd/Cu catalyst, followed by an electrophilic cyclization of the resulting N,N-dialkyl-o-(1-alkynyl)anilines using I2 in CH2Cl2. Aryl-, vinylic-, alkyl-, and silyl-substituted terminal acetylenes undergo this process to produce excellent yields of 3-iodoindoles. The reactivity of the carbon-nitrogen bond cleavage during cyclization follows the following order: Me > n-Bu, Me > Ph, and cyclohexyl > Me. Subsequent palladium-catalyzed Sonogashira, Suzuki, and Heck reactions of the resulting 3-iodoindoles proceed smoothly in good yields.

  2. Continuous-Flow O-Alkylation of Biobased Derivatives with Dialkyl Carbonates in the Presence of Magnesium-Aluminium Hydrotalcites as Catalyst Precursors.

    PubMed

    Cattelan, Lisa; Perosa, Alvise; Riello, Piero; Maschmeyer, Thomas; Selva, Maurizio

    2017-01-31

    The base-catalysed reactions of OH-bearing biobased derivatives (BBDs) including glycerol formal, solketal, glycerol carbonate, furfuryl alcohol and tetrahydrofurfuryl alcohol with non-toxic dialkyl carbonates (dimethyl and diethyl carbonate) were explored under continuous-flow (CF) conditions in the presence of three Na-exchanged Y- and X-faujasites (FAUs) and four Mg-Al hydrotalcites (HTs). Compared to previous etherification protocols mediated by dialkyl carbonates, the reported procedure offers substantial improvements not only in terms of (chemo)selectivity but also for the recyclability of the catalysts, workup, ease of product purification and, importantly, process intensification. Characterisation studies proved that both HT30 and KW2000 hydrotalcites acted as catalyst precursors: during the thermal activation pre-treatments, the typical lamellar structure of the hydrotalcite was broken down gradually into a MgO-like phase (periclase) or rather a magnesia-alumina solid solution, which was the genuine catalytic phase.

  3. Growth mechanisms of 2D organic assemblies generated from dialkylated melaminium derivatives: the length difference of the two alkyl chains that matters.

    PubMed

    Xu, Jun; Wu, Guanglu; Wang, Zhiqiang; Zhang, Xi

    2013-08-27

    This research is aimed to understand the growth mechanisms for self-assembly of dialkylated melamine derivatives. The dialkylated melamine derivatives with different alkyl chains (Mela-m-n) are able to self-assemble with hydrochloric acid in dichloromethane to form 2D organic assemblies, exhibiting similar lamellar structures as Mela-n·HCl with identical alkyl chains. The most interesting finding is that the growth mechanism of Mela-n·HCl with identical alkyl chains is revealed to be layer growth, while Mela-m-n·HCl with asymmetric alkyl chains adopts a spiral growth mechanism. The asymmetric alkyl chains in Mela-m-n may lead to the formation of dislocation, which is responsible for the spiral growth mechanism.

  4. Urinary Dialkyl Phosphate Concentrations and Lung Function Parameters in Adolescents and Adults: Results from the Canadian Health Measures Survey

    PubMed Central

    Ye, Ming; Beach, Jeremy; Martin, Jonathan W.; Senthilselvan, Ambikaipakan

    2015-01-01

    Background: Epidemiological studies have reported associations between lung function parameters and organophosphate (OP) pesticide exposures in agricultural occupations, but to our knowledge associations have not been evaluated in general populations. Objectives: We examined associations between OP metabolite dialkyl phosphates (DAPs) and lung function using data from the Canadian Health Measures Survey (CHMS) Cycle 1. Methods: Forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), FEV1/FVC ratio, and forced expiratory flow between 25% and 75% of FVC (FEF25%–75%) were measured for 4,446 CHMS participants. Urinary concentrations of six DAP metabolites (DMP, DMTP, DMDTP, DEP, DETP, and DEDTP), smoking status, and other predictors of lung function were also measured in the CHMS-Cycle 1. Multiple linear regression analyses were used to examine the relationship between total DAP concentrations (ΣDAPs) and lung function in adolescents (12–19 years) and adults (20–79 years). Results: In adults, estimates from multiple regression analyses suggested that a 1-unit increase on natural logarithmic scale (171% increase on the original scale) in the creatinine-corrected urinary concentration (nanomoles per gram creatinine) of ΣDAP was associated with a 32.6-mL (95% CI: –57.2, –8.1) reduction in FVC, 32.6-mL (95% CI: –59.0, –6.3) reduction in FEV1, 0.2% (95% CI: –0.6, 0.2) reduction in FEV1/FVC ratio, and 53.1-mL/sec (95% CI: –113.9, 7.7) reduction in FEF25%–75%. In adolescents, associations between ΣDAP and FEV1 were closer to the null and positive for FVC, whereas associations with FEV1/FVC and FEF25%–75% were negative, as in adults. However, none of the associations were significant in adolescents. Conclusions: The negative association between ΣDAP and lung function in adult participants suggests a detrimental effect of OP pesticides on lung function in the adult general population. Further studies using prospective designs are

  5. Technetium chemistry

    SciTech Connect

    Burns, C.; Bryan, J.; Cotton, F.; Ott, K.; Kubas, G.; Haefner, S.; Barrera, J.; Hall, K.; Burrell, A.

    1996-04-01

    Technetium chemistry is a young and developing field. Despite the limited knowledge of its chemistry, technetium is the workhorse for nuclear medicine. Technetium is also a significant environmental concern because it is formed as a byproduct of nuclear weapons production and fission-power generators. Development of new technetium radio-pharmaceuticals and effective environmental control depends strongly upon knowledge of basic technetium chemistry. The authors performed research into the basic coordination and organometallic chemistry of technetium and used this knowledge to address nuclear medicine and environmental applications. This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).

  6. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Twelve new chemistry expermiments are described. Broad areas covered include atomic structure, solubility, gaseous diffusion, endothermic reactions, alcohols, equilibrium, atomic volumes, and some improvised apparatus. (PS)

  7. Is hair analysis for dialkyl phosphate metabolites a suitable biomarker for assessing past acute exposure to organophosphate pesticides?

    PubMed

    Tsatsakis, A M; Tutudaki, M; Tzatzarakis, M N; Dawson, A; Mohamed, F; Christaki, M; Alegakis, A K

    2012-03-01

    In the present paper, the possibility to use dialkyl phosphate metabolites (DAPs) hair segmental analysis as a biomarker of past acute exposure to organophosphates is examined. Hair samples of four acute poisoning survivors were collected and segmental hair analysis was performed. The total hair samples were divided to 1 cm segments and analysed by gas chromatography-mass spectrometry (GC-MS) for the presence of four DAP metabolites, dimethyl phosphate (DMP), diethyl phosphate (DEP), diethyl thiophosphate (DETP) and diethyl dithiophosphate (DEDTP). Results were examined under the light of pesticide type and time of hair sample collection. Although DAPs were detected all along the hair shaft, higher concentrations (peaks) were detected in the segments proximate to the suicide period. It was also observed that the elevated concentrations of the present metabolites corresponded to the ones produced by the ingested parent compound. Conclusively, measurements of DAPs in the appropriate hair segments of OP-poisoned patients can be used for assessing past acute exposure to organophosphates in certain cases.

  8. Simple dialkyl pyrazole-3,5-dicarboxylates show in vitro and in vivo activity against disease-causing trypanosomatids.

    PubMed

    Reviriego, Felipe; Olmo, Francisco; Navarro, Pilar; Marín, Clotilde; Ramírez-Macías, Inmaculada; García-España, Enrique; Albelda, María Teresa; Gutiérrez-Sánchez, Ramón; Sánchez-Moreno, Manuel; Arán, Vicente J

    2017-04-03

    The synthesis and antiprotozoal activity of some simple dialkyl pyrazole-3,5-dicarboxylates (compounds 2-6) and their sodium salts (pyrazolates) (compounds 7-9) against Trypanosoma cruzi, Leishmania infantum and Leishmania braziliensis are reported. In most cases the studied compounds showed, especially against the clinically significant amastigote forms, in vitro activities higher than those of the reference drugs (benznidazole for T. cruzi and glucantime for Leishmania spp.); furthermore, the low non-specific cytotoxicities against Vero cells and macrophages shown by these compounds led to good selectivity indexes, which are 8-72 times higher for T. cruzi amastigotes and 15-113 times higher for Leishmania spp. amastigotes than those of the respective reference drugs. The high efficiency of diethyl ester 3 and its sodium salt 8 against the mentioned protozoa was confirmed by further in vitro assays on infection rates and by an additional in vivo study in a murine model of acute and chronic Chagas disease. The inhibitory capacity of compounds 3 and 8 on the essential iron superoxide dismutase of the aforementioned parasites may be related to the observed anti-trypanosomatid activity. The low acute toxicity of compounds 3 and 8 in mice is also reported in this article.

  9. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Outlines laboratory procedures, demonstrations, teaching suggestions, and content information related to chemistry. Topics include polarizing power; calorimetry and momentum; microcomputers in school chemistry; a constant-volume dispenser for liquids, floating magnets, and crystal lattices; preparation of chromium; and solvent polarity and…

  10. Circumstellar chemistry

    NASA Technical Reports Server (NTRS)

    Glassgold, Alfred E.; Huggins, Patrick J.

    1987-01-01

    The study of the outer envelopes of cool evolved stars has become an active area of research. The physical properties of CS envelopes are presented. Observations of many wavelengths bands are relevant. A summary of observations and a discussion of theoretical considerations concerning the chemistry are summarized. Recent theoretical considerations show that the thermal equilibrium model is of limited use for understanding the chemistry of the outer CS envelopes. The theoretical modeling of the chemistry of CS envelopes provides a quantitive test of chemical concepts which have a broader interest than the envelopes themselves.

  11. Catalytic Chemistry.

    ERIC Educational Resources Information Center

    Borer, Londa; And Others

    1996-01-01

    Describes an approach for making chemistry relevant to everyday life. Involves the study of kinetics using the decomposition of hydrogen peroxide by vegetable juices. Allows students to design and carry out experiments and then draw conclusions from their results. (JRH)

  12. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1980

    1980-01-01

    Describes equipment, activities, and experiments useful in chemistry instruction, including among others, a rapid method to determine available chlorine in bleach, simple flame testing apparatus, and a simple apparatus demonstrating the technique of flash photolysis. (SK)

  13. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1973

    1973-01-01

    Several ideas are proposed for chemistry teachers to try in their classrooms. Subjects included are polymerization of acrylate, polymerization of styrene, conductivity, pollution, preparation of chlorine, redox equations, chemiluminescence, and molecular sieves. (PS)

  14. Nuclear Chemistry.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1979

    1979-01-01

    Provides a brief review of the latest developments in nuclear chemistry. Nuclear research today is directed toward increased activity in radiopharmaceuticals and formation of new isotopes by high-energy, heavy-ion collisions. (Author/BB)

  15. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Describes 13 activities, experiments and demonstrations, including the preparation of iron (III) chloride, simple alpha-helix model, investigating camping gas, redox reactions of some organic compounds, a liquid crystal thermometer, and the oxidation number concept in organic chemistry. (JN)

  16. Precolumbian Chemistry.

    ERIC Educational Resources Information Center

    Robinson, Janet Bond

    1995-01-01

    Describes the content and development of a curriculum that provides an approach to descriptive chemistry and the history of technology through consideration of the pottery, metallurgy, pigments, dyes, agriculture, and medicine of pre-Columbian people. (DDR)

  17. Stratospheric chemistry

    SciTech Connect

    Brune, W.H. )

    1991-01-01

    Advances in stratospheric chemistry made by investigators in the United States from 1987 to 1990 are reviewed. Subject areas under consideration include photochemistry of the polar stratosphere, photochemistry of the global stratosphere, and assessments of inadvertent modification of the stratosphere by anthropogenic activity. Particular attention is given to early observations and theories, gas phase chemistry, Antarctic observations, Arctic observations, odd-oxygen, odd-hydrogen, odd-nitrogen, halogens, aerosols, modeling of stratospheric ozone, and reactive nitrogen effects.

  18. Evidence of moisture control on the methylation of branched glycerol dialkyl glycerol tetraethers in semi-arid and arid soils

    NASA Astrophysics Data System (ADS)

    Dang, Xinyue; Yang, Huan; Naafs, B. David A.; Pancost, Richard D.; Xie, Shucheng

    2016-09-01

    The distribution of bacterial branched glycerol dialkyl glycerol tetraethers (brGDGTs) is influenced by growth temperature and pH. This results in the widespread application of the brGDGT-based MBT(‧)/CBT proxy (MBT - methylation of branched tetraethers, CBT - cyclization of branched tetraethers) in terrestrial paleo-environmental reconstructions. Recently, it was shown that the amount of precipitation could also have an impact on CBT, as well as the abundance of brGDGTs relative to that of archaeal isoprenoidal (iso)GDGTs (Ri/b) and the absolute abundance of brGDGTs, potentially complicating the use of MBT/CBT as paleothermometer. However, the full influence of hydrology, and in particular soil water content (SWC), on GDGT distributions remains unclear. Here we investigated variations in the GDGT distribution across a SWC gradient (0-61%) around Qinghai Lake in the Tibetan Plateau, an arid to semiarid region in China. Our results demonstrate that SWC affects the brGDGT distribution. In particular, we show that SWC has a clear impact on the degree of methylation of C6-methylated brGDGTs, whereas C5-methylated brGDGTs are more impacted by temperature. This results in a combined SWC and temperature control on MBT‧. In this context we propose a diagnostic parameter, the IR6ME (relative abundance of C6-methylated GDGTs) index, to evaluate the applicability of brGDGT-based paleotemperature reconstructions. Using the global dataset, expanded with our own data, MBT‧ has a significant correlation with mean annual air temperature when IR6ME < 0.5, allowing for the use of MBT‧/CBT as temperature proxy. However, MBT‧ has a significant correlation with mean annual precipitation (i.e., a substantial reflection of SWC impact) when IR6ME > 0.5, implying that MBT‧ may respond to hydrological change in these regions and can be used as a proxy for MAP.

  19. Concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers in sinking particles south of Java

    NASA Astrophysics Data System (ADS)

    Chen, Wenwen; Mohtadi, Mahyar; Schefuß, Enno; Mollenhauer, Gesine

    2016-06-01

    In this study, we obtained concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers (GDGTs) in a one-year time-series of sinking particles collected with a sediment trap moored from December 2001 to November 2002 at 2200 m water depth south of Java in the eastern Indian Ocean. We investigate the seasonality of alkenone and GDGT fluxes as well as the potential habitat depth of the Thaumarchaeota producing the GDGTs entrained in sinking particles. The alkenone flux shows a pronounced seasonality and ranges from 1 μg m-2 d-1 to 35 μg m-2 d-1. The highest alkenone flux is observed in late September during the Southeast monsoon, coincident with high total organic carbon fluxes as well as high net primary productivity. Flux-weighted mean temperature for the high flux period using the alkenone-based sea-surface temperature (SST) index U37K‧ is 26.7 °C, which is similar to satellite-derived Southeast (SE) monsoon SST (26.4 °C). The GDGT flux displays a weaker seasonality than that of the alkenones. It is elevated during the SE monsoon period compared to the Northwest (NW) monsoon and intermonsoon periods (approximately 2.5 times), which is probably related to seasonal variation of the abundance of Thaumarchaeota, or to enhanced export of GDGTs by aggregation with sinking phytoplankton detritus. Flux-weighted mean temperature inferred from the GDGT-based TEX86H index is 26.2 °C, which is 1.8 °C lower than mean annual (ma) SST but similar to SE monsoon SST. As the time series of TEX86H temperature estimates, however, does not record a strong seasonal amplitude, we infer that TEX86H reflects ma upper thermocline temperature at approximately 50 m water depth.

  20. Determinants of urinary concentrations of dialkyl phosphates among pregnant women in Canada - Results from the MIREC study.

    PubMed

    Sokoloff, Katia; Fraser, William; Arbuckle, Tye E; Fisher, Mandy; Gaudreau, Eric; LeBlanc, Alain; Morisset, Anne-Sophie; Bouchard, Maryse F

    2016-09-01

    Organophosphate (OP) insecticides are commonly used in agriculture. Their use decreased in recent years as they were gradually replaced by other pesticides, but some OPs are still among the insecticides most used in Canada. Exposure to elevated levels of OPs during pregnancy has been associated with adverse birth outcomes and poorer neurodevelopment in children. The objective of the present study was to examine the relationship between the concentrations of OP pesticides urinary dialkyl phosphate (DAP) metabolites and various factors that are potential sources of exposure or determinants of DAP levels. In the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, six DAPs were measured in 1st trimester urine samples of 1884 pregnant women living in Canada. They were grouped into sums of dimethyl alkyl phosphates (DMAP) and diethyl alkyl phosphates (DEAP) for statistical analysis. We found that 93% of women had at least one DAP detected in their urine. Geometric means (GM) of specific gravity-corrected levels for urine dilution were 59 (95% CI 56-62) and 21 (95% CI 20-22) nmol/L for DMAP and DEAP, respectively. The following characteristics were significantly associated with higher urinary concentrations of DMAP or DEAP: higher education, nulliparous, normal pre-pregnancy body mass index, non-smoker, not fasting at sampling, winter season at sampling, and early and late day collection times. Dietary items that were significantly related with higher urinary concentrations included higher intake of citrus fruits, apple juice, sweet peppers, tomatoes, beans and dry peas, soy and rice beverages, whole grain bread, white wine and green and herbal teas. This study indicates that exposure to these compounds is quasi-ubiquitous. The factors associated with greater DAP levels identified here could be useful to regulatory agencies for risk analysis and management. However, some exposure misclassification might occur due to the single DAP measurement available, and

  1. Distribution of Glycerol Dialkyl Glycerol Tetraethers in Soils from Two Environmental Transects in the U.S

    NASA Astrophysics Data System (ADS)

    Dirghangi, S. S.; Pagani, M.; Hren, M. T.; Tipple, B. J.

    2012-12-01

    Glycerol Dialkyl Glycerol Tetraethers (GDGT) of both archaeal and bacterial origins form the basis of new temperature proxies applicable to soils, lake and marine sediments. In soils, branched GDGTs are prevalent and the abundance of methyl or cyclic groups in these compounds has been calibrated to mean-annual temperatures using MBT and CBT indices. However, soil pH is also known to be an important variable controlling the distribution of branched GDGTs. The factors influencing soil pH include bedrock type, vegetation, soil microbial activity, precipitation amount, drainage etc. For this study, we evaluate the distribution of branched GDGTs from two soil transects in the United States: a dry, western transect that covers four western states, and a wet, east-coast transect from Maine to Georgia in order to assess the effect of precipitation on the distribution of soil GDGTs. Our results show distinctly different GDGT distributions across climatic regions, with dry western soils predominantly characterized by crenarchaeal isoprenoidal GDGTs and moist-temperate east-coast transect soils expressing mostly branched GDGTs. Predominance of isoprenoidal GDGTs in the western soils is related to the degree of aeration which in turn is related to precipitation amount. We also observe a substantial increase in the offset between measured mean-annual temperatures (MAT) and MBT/CBT-based MAT below an annual precipitation of 700-800mm per year. These data suggest that while soil tetraethers work well as a temperature proxy in moist-temperate regimes, they do not produce reliable measurements of temperature in sediments sourced from areas with less than 700-800mm per year precipitation.

  2. Oxygen Diffusion Enables Anti-Wear Boundary Film Formation on Titanium Surfaces in Zinc-Dialkyl-Dithiophosphate (ZDDP)-Containing Lubricants

    SciTech Connect

    Qu, Jun; Blau, Peter Julian; Howe, Jane Y; Meyer III, Harry M

    2009-01-01

    This paper reports a wear reduction by up to six orders of magnitude for Ti-6Al-4V alloy when treated by an oxygen diffusion (OD) process and subsequently tested in a zinc-dialkyl-dithiophosphate (ZDDP)-containing lubricant. In addition to case hardening, it is discovered that OD enables the formation of an anti-wear boundary film on the titanium surface. Transmission electron microscopy and surface chemical analyses revealed that this boundary film has a two-layer structure comprising an amorphous oxide interlayer and a ZDDP-based top film with complex compounds.

  3. A joint experimental and theoretical investigation of kinetics and mechanistic study in a synthesis reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of benzhydrazide.

    PubMed

    Kazemian, Mohammad Amin; Habibi-Khorassani, Sayyed Mostafa; Ebrahimi, Ali; Maghsoodlou, Malek Taher; Jahani, Peyman Mohammadzadeh; Ghahramaninezhad, Mahbobeh

    2012-12-01

    Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine (TPP) and dialkyl acetylenedicarboxylates, in the presence of NH-acids, such as benzhydrazide. To determine the kinetic parameters of the reactions, they were monitored by UV spectrophotometery. The second order fits were automatically drawn and the values of the second order rate constant (k(2)) were calculated using standard equations within the program. At the temperature range studied the dependence of the second order rate constant (Ln k(2)) on reciprocal temperature was compatible with Arrhenius equation. This provided the relevant plots to calculate the activation energy of all reactions. Furthermore, useful information were obtained from studies of the effect of solvent, structure of reactants (different alkyl groups within the dialkyl acetylenedicarboxylates) and also concentration of reactants on the rate of reactions. On the basis of experimental data the proposed mechanism was confirmed according to the obtained results and a steady state approximation and the first step (k(2)) and third (k(3)) steps of the reactions were recognized as the rate determining steps, respectively. In addition, three speculative proposed mechanisms were theoretically investigated using quantum mechanical calculation. The results, arising from the second and third speculative mechanisms, were far from the experimental data. Nevertheless, there was a good agreement between the theoretical kinetic data, emerge from the first speculative mechanism, and experimental kinetic data of proposed mechanism.

  4. Polymer Chemistry

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  5. Chemistry Experiments

    NASA Technical Reports Server (NTRS)

    Brasseur, Guy; Remsberg, Ellis; Purcell, Patrick; Bhatt, Praful; Sage, Karen H.; Brown, Donald E.; Scott, Courtney J.; Ko, Malcolm K. W.; Tie, Xue-Xi; Huang, Theresa

    1999-01-01

    The purpose of the chemistry component of the model comparison is to assess to what extent differences in the formulation of chemical processes explain the variance between model results. Observed concentrations of chemical compounds are used to estimate to what degree the various models represent realistic situations. For readability, the materials for the chemistry experiment are reported in three separate sections. This section discussed the data used to evaluate the models in their simulation of the source gases and the Nitrogen compounds (NO(y)) and Chlorine compounds (Cl(y)) species.

  6. A study of the antiwear behavior and oxidation stability of fluorinated zinc dialkyl dithio phosphate in the presence of antioxidants

    NASA Astrophysics Data System (ADS)

    Somayaji, Anuradha

    The antiwear additive Zinc dialkyl dithio phosphate (ZDDP) is one of the most important components of engine-oil additives and a major source of phosphorus. Phosphorus plays a crucial part in mitigating engine wear, yet has been proven harmful to modern catalytic converters. Progressive regulatory caps on phosphorus content in automotive lubricants have led to widespread efforts to reduce its levels. A new fluorinated ZDDP (F-ZDDP) complex developed at the University of Texas at Arlington has found to breakdown at lower temperatures compared to ZDDP and has showed better wear performance than ZDDP alone. This would allow the possibility of further reduction of phosphorus in engine oils than current levels. This work begins with a study of the interaction of ZDDP and fluorinated ZDDP with the antioxidant alkylated diphenyl amine. The impact of antioxidant on wear performance was examined using a custom-built ball-on-cylinder tribometer. Interactions between ZDDP and fluorinated ZDDP with antioxidant were studied using Fourier transform infrared spectroscopy and nuclear magnetic resonance, and the surface of the tribofilm was examined using scanning electron microscopy, transmission electron microscopy and Auger electron spectroscopy. Nanoscale mechanical properties of in-situ tribofilms generated from ZDDP and F-ZDDP in the presence of alkylated diphenyl amine are compared to films obtained from ZDDP and F-ZDDP without antioxidant. Tribofilms in the thickness regime of 100nm to 200nm are developed in-situ during wear tests using ZDDP and F-ZDDP. The influence of alkylated diphenyl amine on the creation and characteristics of these tribofilms is studied. Nanomechanical properties such as hardness, modulus, scratch resistance and nano-wear resistance of the films thus formed are explored to understand the effect of various variables on the nature of these tribofilms. A focused ion beam is used to image the substrate-tribofilm interface and measure tribofilm thickness

  7. Wide distribution of autochthonous branched glycerol dialkyl glycerol tetraethers (bGDGTs) in U.S. Great Basin hot springs.

    PubMed

    Hedlund, Brian P; Paraiso, Julienne J; Williams, Amanda J; Huang, Qiuyuan; Wei, Yuli; Dijkstra, Paul; Hungate, Bruce A; Dong, Hailiang; Zhang, Chuanlun L

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are membrane-spanning lipids that likely stabilize membranes of some bacteria. Although bGDGTs have been reported previously in certain geothermal environments, it has been suggested that they may derive from surrounding soils since bGDGTs are known to be produced by soil bacteria. To test the hypothesis that bGDGTs can be produced by thermophiles in geothermal environments, we examined the distribution and abundance of bGDGTs, along with extensive geochemical data, in 40 sediment and mat samples collected from geothermal systems in the U.S. Great Basin (temperature: 31-95°C; pH: 6.8-10.7). bGDGTs were found in 38 out of 40 samples at concentrations up to 824 ng/g sample dry mass and comprised up to 99.5% of total GDGTs (branched plus isoprenoidal). The wide distribution of bGDGTs in hot springs, strong correlation between core and polar lipid abundances, distinctness of bGDGT profiles compared to nearby soils, and higher concentration of bGDGTs in hot springs compared to nearby soils provided evidence of in situ production, particularly for the minimally methylated bGDGTs I, Ib, and Ic. Polar bGDGTs were found almost exclusively in samples ≤70°C and the absolute abundance of polar bGDGTs correlated negatively with properties of chemically reduced, high temperature spring sources (temperature, H2S/HS(-)) and positively with properties of oxygenated, low temperature sites (O2, NO(-) 3). Two-way cluster analysis and nonmetric multidimensional scaling based on relative abundance of polar bGDGTs supported these relationships and showed a negative relationship between the degree of methylation and temperature, suggesting a higher abundance for minimally methylated bGDGTs at high temperature. This study presents evidence of the widespread production of bGDGTs in mats and sediments of natural geothermal springs in the U.S. Great Basin, especially in oxygenated, low-temperature sites (≤70°C).

  8. In situ produced branched glycerol dialkyl glycerol tetraethers in suspended particulate matter from the Yenisei River, Eastern Siberia

    NASA Astrophysics Data System (ADS)

    De Jonge, Cindy; Stadnitskaia, Alina; Hopmans, Ellen C.; Cherkashov, Georgy; Fedotov, Andrey; Sinninghe Damsté, Jaap S.

    2014-01-01

    Soil-derived branched glycerol dialkyl glycerol tetraethers (brGDGTs) in marine river fan sediments have a potential use for determining changes in the mean annual temperature (MAT) and pH of the river watershed soils. Prior to their incorporation in marine sediments, the compounds are transported to the marine system by rivers. However, emerging evidence suggests that the brGDGTs in freshwater systems can be derived from both soil run-off and in situ production. The production of brGDGTs in the river system can complicate the interpretation of the brGDGT signal delivered to the marine system. Therefore, we studied the distribution of brGDGT lipids in suspended particulate matter (SPM) of the Yenisei River. Chromatographic improvements allowed quantification of the recently described hexamethylated brGDGT isomer, characterized by having two methyl groups at the 6/6‧ instead of the 5/5‧ positions, in an environmental dataset for the first time. This novel compound was the most abundant brGDGT in SPM from the Yenisei. Its fractional abundance correlated well with that of the 6-methyl isomer of the hexamethylated brGDGT that contains one cyclopentane moiety. The Yenisei River watershed is characterized by large differences in MAT (>11 °C) as it spans a large latitudinal range (46-73°N), which would be expected to be reflected in brGDGT distributions of its soils. However, the brGDGT distributions in its SPM show little variation. Furthermore, the reconstructed pH values are high compared to the watershed soil pH. We, therefore, hypothesize that the brGDGTs in the Yenisei River SPM are predominantly produced in situ and not primarily derived from erosion of soil. This accounts for the absence of a change in the temperature signal, as the river water temperature is more stable. Using a lake calibration, the reconstructed temperature values agree with the mean summer temperatures (MST) recorded. The brGDGTs delivered to the sea by the Yenisei River during this

  9. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1980

    1980-01-01

    Presents 12 chemistry notes for British secondary school teachers. Some of these notes are: (1) a simple device for testing pH-meters; (2) portable fume cupboard safety screen; and (3) Mass spectroscopy-analysis of a mass peak. (HM)

  10. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1976

    1976-01-01

    Describes several chemistry projects, including solubility, formula for magnesium oxide, dissociation of dinitrogen tetroxide, use of 1-chloro-2, 4-dinitrobenzene, migration of ions, heats of neutralizations, use of pocket calculators, sonic cleaning, oxidation states of manganese, and cell potentials. Includes an extract from Chemical Age on…

  11. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Short articles on the alkylation of aniline, the preparation and properties of perbromate, using scrap copper in chemistry instruction, a safe method of burning hydrogen, and the use of an ion-charge model as an alternative to the mole concept in secondary school instruction. (AL)

  12. Confectionary Chemistry.

    ERIC Educational Resources Information Center

    Levine, Elise Hilf

    1996-01-01

    Presents activities and demonstrations that enable teachers to use various types of confections as tactile experiences to spark chemistry students' interest and generate enthusiasm for learning. Presents uses of candy in teaching about atomic structure, spontaneous nuclear decay, chemical formulas, fractoluminescence, the effect of a molecular…

  13. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Short articles on the kinetics of the hydrogen peroxide-iodide ion reaction, simulation of fluidization catalysis, the use of Newman projection diagrams to represent steric relationships in organic chemistry, the use of synthetic substrates for proteolytic enzyme reactions, and two simple clock reactions"--hydrolysis of halogenoalkanes and…

  14. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Presents chemistry experiments, laboratory procedures, demonstrations, teaching suggestions, and classroom materials/activities. These include: game for teaching ionic formulas; method for balancing equations; description of useful redox series; computer programs (with listings) for water electrolysis simulation and for determining chemical…

  15. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Presents chemistry experiments, laboratory procedures, demonstrations, and classroom materials/activities. These include: experiments on colloids, processing of uranium ore, action of heat on carbonates; color test for phenols and aromatic amines; solvent properties of non-electrolytes; stereoscopic applications/methods; a valency balance;…

  16. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Presents procedures, experiments, demonstrations, teaching suggestions, and information on a variety of chemistry topics including, for example, inert gases, light-induced reactions, calculators, identification of substituted acetophenones, the elements, analysis of copper minerals, extraction of metallic strontium, equilibrium, halogens, and…

  17. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1978

    1978-01-01

    Describes some laboratory apparatus, chemistry experiments and demonstrations, such as a Kofler block melting point apparatus, chromatographic investigation of the phosphoric acid, x-ray diffraction, the fountain experiment, endothermic sherbet, the measurement of viscosity, ionization energies and electronic configurations. (GA)

  18. Microscale Chemistry and Green Chemistry: Complementary Pedagogies

    NASA Astrophysics Data System (ADS)

    Singh, Mono M.; Szafran, Zvi; Pike, R. M.

    1999-12-01

    This paper describes the complementary nature of microscale chemistry and green chemistry. Green chemistry emphasizes the concepts of atom economy, source reduction, pathway modification, solvent substitution, and pollution prevention as means of improving the environmental impact of industrial chemistry. Microscale chemistry serves as a tool for incorporating green chemistry ideas across the curriculum in educational institutions. Examples are drawn from microscale laboratory experiments to illustrate the pedagogic connection between the two areas.

  19. Polynitrogen Chemistry

    DTIC Science & Technology

    2013-09-24

    4N3, while As(C6H5)4N3 presents a borderline case.23 Theoretical Calculations High-level theoretical studies of nitrogen, oxygen, selenium and...Dixon, D. A.; Christe, K. O., "Thermochemical Properties of Selenium Fluorides, Oxides, and Oxofluorides," Inorganic Chemistry, p. 2472, vol. 51, (2012...34Thermochemical Properties of Selenium Fluorides, Oxides, and Oxofluorides," Inorg. Chem., p. 2472, vol. 51, (2012). 26. K. S. Thanthiriwatte, M. Vasiliu

  20. Computational chemistry

    NASA Technical Reports Server (NTRS)

    Arnold, J. O.

    1987-01-01

    With the advent of supercomputers, modern computational chemistry algorithms and codes, a powerful tool was created to help fill NASA's continuing need for information on the properties of matter in hostile or unusual environments. Computational resources provided under the National Aerodynamics Simulator (NAS) program were a cornerstone for recent advancements in this field. Properties of gases, materials, and their interactions can be determined from solutions of the governing equations. In the case of gases, for example, radiative transition probabilites per particle, bond-dissociation energies, and rates of simple chemical reactions can be determined computationally as reliably as from experiment. The data are proving to be quite valuable in providing inputs to real-gas flow simulation codes used to compute aerothermodynamic loads on NASA's aeroassist orbital transfer vehicles and a host of problems related to the National Aerospace Plane Program. Although more approximate, similar solutions can be obtained for ensembles of atoms simulating small particles of materials with and without the presence of gases. Computational chemistry has application in studying catalysis, properties of polymers, all of interest to various NASA missions, including those previously mentioned. In addition to discussing these applications of computational chemistry within NASA, the governing equations and the need for supercomputers for their solution is outlined.

  1. Occurrence and abundance of 6-methyl branched glycerol dialkyl glycerol tetraethers in soils: Implications for palaeoclimate reconstruction

    NASA Astrophysics Data System (ADS)

    De Jonge, Cindy; Hopmans, Ellen C.; Zell, Claudia I.; Kim, Jung-Hyun; Schouten, Stefan; Sinninghe Damsté, Jaap S.

    2014-09-01

    The distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in soils has been shown to correlate with the soil pH and the mean annual air temperature (MAT). This has been used to perform palaeoclimate reconstructions based on brGDGTs recovered from palaeosoils, freshwater, and marine sedimentary archives. Recently described 6-methyl brGDGTs were shown to co-elute with the 5-methyl brGDGTs that are used to calculate the CBT and MBT‧ indices used as palaeoclimate proxies. The impact of these 6-methyl brGDGTs on the established palaeoclimate proxies is unknown and will depend on their abundance in soils. Using improved chromatography, we quantified the fractional abundance of 6-methyl brGDGTs in globally distributed soils and show that they are abundant components, comprising on average 24% of the total amount of brGDGTs. All penta- and hexa-methylated brGDGTs (i.e. with zero to two cyclopentane moieties) were shown to comprise both 5- and 6-methyl isomers. The fractional abundances of the six 6-methyl brGDGTs correlate positively with each other, suggesting a common biological source in most soils, and correlate strongly with soil pH. The presence of the 6-methyl brGDGTs introduced scatter in the original MBT‧/CBT-MAT calibration and caused a dependence on soil pH of the MBT‧. Exclusion of the 6-methyl brGDGTs from the MBT‧, i.e. the newly defined MBT‧5ME, shows that it is no longer related to soil pH. The correlation with MAT is improved, reducing the residual mean error (RMSE) from 6.2 to 4.8 °C. Also, the correlation of the CBT after the exclusion of the 6-methyl brGDGTs (defined as CBT5ME) with soil pH slightly improved. Furthermore, the separate quantification of the 6-methyl brGDGTs allows the definition of new indices. The CBT‧, which comprises the 6-methyl brGDGTs, is a substantially improved alternative to the CBT5ME, reducing the RMSE from 0.8 to 0.5 pH units. Also, the accuracy of MAT reconstructions can be improved using a

  2. Fluxes and distribution of intact glycerol dialkyl glycerol tetraether membrane lipids in the water column of Lake Challa, East Africa

    NASA Astrophysics Data System (ADS)

    Weijers, J.; Buckles, L.; Verschuren, D.; Sinninghe Damsté, J. S.

    2009-12-01

    Over the last years, glycerol dialkyl glycerol tetraether (GDGT) membrane lipids have become an interesting tool in palaeoclimate research. Both the TEX86 sea surface temperature proxy, based on isoprenoid GDGT membrane lipids derived from pelagic Crenarchaeota, and the MBT/CBT annual mean air temperature proxy, based on the distribution of branched GDGTs derived from soil bacteria, receive increasing interest to be also applied in lake sediments. Despite successful studies utilizing the TEX86 to reconstruct past lake surface temperatures in two large African lakes, other studies indicated that TEX86 values derived from lake surface sediments differed from what would be expected based on the lake surface water temperatures. In addition, in two tropical lake systems, the distribution of branched GDGT lipids in lake surface sediments appeared to differ from that in the surrounding soils. Both situations suggest production of GDGTs by additional sources in some lake systems, hampering application of earlier mentioned temperature proxies. In order to constrain the provenance and flux of GDGT lipids in one of these lakes, Lake Challa, a freshwater crater lake in East Africa, we used a novel separation technique to analyze both intact and core GDGT membrane lipids in monthly samples derived from a sediment trap installed at 35m depth in the lake. Intact GDGT lipids still contain a functional polar head group which is thought to be lost quickly after cell lysis. Therefore, the presence of such intact GDGT lipids is thought indicative for extant life, most likely autochthonous in origin. High fluxes of intact GDGT-0 lipids, maybe derived from methanogenic Archaea residing in anoxic micro niches in descending particles, occur in July and August during a diatom bloom. High fluxes of both the intact and core isoprenoid GDGT lipid crenarchaeol in December and January clearly reflect the bloom of Crenarchaeota. TEX86 values of both the intact and core isoprenoid GDGTs are

  3. Thin-film transistors based on poly(3,3‴-dialkyl-quarterthiophene) and zinc oxide nanowires with improved ambient stability

    NASA Astrophysics Data System (ADS)

    Vieira, Sara M. C.; Hsieh, Gen-Wen; Unalan, Husnu E.; Dag, Sefa; Amaratunga, Gehan A. J.; Milne, William I.

    2011-03-01

    The ambient stability of thin-film transistors (TFTs) based on zinc oxide (ZnO) nanowires embedded in poly(3,3‴-dialkyl-quarterthiophene) was monitored through time dependence of electrical characteristics over a period of 16 months. The hybrid-based TFT showed an initial hole mobility in the linear regime of 4.2×10-4 cm2/V s. After 16 months storage in ambient conditions (exposed to air, moisture, and light) the mobility decreased to 2.3×10-5 cm2/V s. Comparatively the organic-based TFT lost total carrier mobility after one month storage making the hybrid-based TFTs more suitable for transistor applications when improved stability combined with structural flexibility are required.

  4. Extraction of Am(III), Eu(III) and U(VI) from perchloric acid and mixtures of acids by dialkyl-(diaryl) [diethylcarbamoylmethyl] phosphine oxides

    SciTech Connect

    Chmutova, M.K.; Litvina, M.N.; Nesterova, N.P.; Myasoedov, B.F.; Kabachnik, M.I.

    1992-07-01

    Extraction of Am(III), and Eu(III) and U(VI) from perchloric acid solutions by dialkyl(diaryl) [diethyl-carbamoylmethyl] phosphine oxides (CMPO) has been investigated. It has been shown that elements are extracted more effectively from perchloric acid solutions than from nitric acid. An `anomalous aryl effect` increases sufficiently in perchloric media as compared with nitric media. Solvate numbers of elements also increase in perchloric acid, they being extremely high for aryl-substituted reagents and not so high for alkyl-substituted compounds. It has been shown that in HNO{sub 3} and HClO{sub 4} solutions the value of `anomalous aryl effect` directly depends on the difference in values of element solvate numbers in complexes with aryl- and alkyl-substituted CMPO. Am(III), Eu(III) and U(VI) are not practically extracted from phosphoric and sulphuric acids by CMPO solutions. 16 refs., 7 figs., 3 tabs.

  5. Synthesis and structure-activity relationship of new 1,5-dialkyl-1,5-benzodiazepines as cholecystokinin-2 receptor antagonists.

    PubMed

    Roberts, Karen; Ursini, Antonella; Barnaby, Robert; Cassarà, Paolo G; Corsi, Mauro; Curotto, Giovanni; Donati, Daniele; Feriani, Aldo; Finizia, Gabriella; Marchioro, Carla; Niccolai, Daniela; Oliosi, Beatrice; Polinelli, Stefano; Ratti, Emiliangelo; Reggiani, Angelo; Tedesco, Giovanna; Tranquillini, Maria E; Trist, David G; van Amsterdam, Franciscus T M

    2011-07-15

    This article deals with the synthesis and the activities of some 1,5-dialkyl-3-arylureido-1,5-benzodiazepin-2,4-diones which were prepared as potential CCK2 antagonists, with the intention to find a possible follow up of our lead compound GV150013, showing an improved pharmacokinetic profile. The phenyl ring at N-5 was replaced with more hydrophilic substituents, like alkyl groups bearing basic functions. In some cases, the resolution of the racemic key intermediates 3-amino-benzodiazepines was also accomplished. Among the compounds synthesized and characterised so far in this class, the 5-morpholinoethyl derivative 54, was selected as potential follow up of GV150013 and submitted for further evaluation.

  6. (Pesticide chemistry)

    SciTech Connect

    Barnthouse, L.W.

    1990-09-04

    This report summarizes a trip by L. W. Barnthouse of the Environmental Sciences Division (ESD), Oak Ridge National Laboratory (ORNL), to Hamburg, Federal Republic of Germany (FRG), where he participated in the 7th International Congress of Pesticide Chemistry. He chaired a workshop on experimental systems for determining effects of pesticides on nontarget organisms and gave an oral presentation at a symposium on pesticide risk assessment. Before returning to the United States, Dr. Barnthouse visited the Netherlands Institute for Sea Research in Texel, the Netherlands.

  7. Why Teach Environmental Chemistry?

    ERIC Educational Resources Information Center

    Gardner, Marjorie H.

    1974-01-01

    Discusses the importance of teaching environmental chemistry in secondary school science classes, and outlines five examples of environmental chemistry problems that focus on major concepts of chemistry and have critical implications for human survival and well-being. (JR)

  8. Science Update: Inorganic Chemistry

    ERIC Educational Resources Information Center

    Rawls, Rebecca

    1978-01-01

    This first in a series of articles describing the state of the art of various branches of chemistry reviews inorganic chemistry, including bioinorganic, photochemistry, organometallic, and solid state chemistries. (SL)

  9. Combustion chemistry

    SciTech Connect

    Brown, N.J.

    1993-12-01

    This research is concerned with the development and use of sensitivity analysis tools to probe the response of dependent variables to model input variables. Sensitivity analysis is important at all levels of combustion modeling. This group`s research continues to be focused on elucidating the interrelationship between features in the underlying potential energy surface (obtained from ab initio quantum chemistry calculations) and their responses in the quantum dynamics, e.g., reactive transition probabilities, cross sections, and thermal rate coefficients. The goals of this research are: (i) to provide feedback information to quantum chemists in their potential surface refinement efforts, and (ii) to gain a better understanding of how various regions in the potential influence the dynamics. These investigations are carried out with the methodology of quantum functional sensitivity analysis (QFSA).

  10. Science Update: Inorganic Chemistry.

    ERIC Educational Resources Information Center

    Rawls, Rebecca

    1981-01-01

    Describes areas of inorganic chemistry which have changed dramatically in the past year or two, including photochemistry, electrochemistry, organometallic complexes, inorganic reaction theory, and solid state chemistry. (DS)

  11. N,N'-Dialkyl-N,N'-diaryl-1,10-phenanthroline-2,9-dicarboxamides as donor ligands for separation of rare earth elements with a high and unusual selectivity. DFT computational and experimental studies.

    PubMed

    Ustynyuk, Yu A; Borisova, N E; Babain, V A; Gloriozov, I P; Manuilov, A Y; Kalmykov, S N; Alyapyshev, M Yu; Tkachenko, L I; Kenf, E V; Ustynyuk, N A

    2015-05-01

    N,N'-Dialkyl-N,N'-diaryl-1,10-phenanthroline-2,9-dicarboxamides (IV) were predicted (DFT simulation) and then were proved experimentally to be efficient donor ligands with high and unusual selectivity for the extraction separation of lanthanides. Distribution coefficients D of lanthanide cations in two-phase aqueous solution-polar organic solvent decrease with increasing Ln(3+) atomic number. The selectivity factors SFLn1/Ln2 for adjacent lanthanide ions were found to be about 3.

  12. Trace Chemistry

    NASA Technical Reports Server (NTRS)

    Radhakrishnan, Krishnan; Whitefield, Philip

    1999-01-01

    The goals of the trace chemistry group were to identify the processes relevant to aerosol and aerosol precursor formation occurring within aircraft gas turbine engines; that is, within the combustor, turbine, and nozzle. The topics of discussion focused on whether the chemistry of aerosol formation is homogeneous or heterogeneous; what species are important for aerosol and aerosol precursor formation; what modeling/theoretical activities to pursue; what experiments to carry out that both support modeling activities and elucidate fundamental processes; and the role of particulates in aerosol and aerosol precursor formation. The consensus of the group was that attention should be focused on SO2, SO3, and aerosols. Of immediate concern is the measurement of the concentration of the species SO3, SO2, H2SO4 OH, HO2, H2O2, O, NO, NO2, HONO, HNO3, CO, and CO2 and particulates in various engines, both those currently in use and those in development. The recommendation was that concentration measurements should be made at both the combustor exit and the engine exit. At each location the above species were classified into one of four categories of decreasing importance, Priority I through IV, as follows: Combustor exit: Priority I species - SO3:SO2 ratio, SO3, SO2, and particulates; Priority II species: OH and O; Priority III species - NO and NO2; and Priority IV species - CO and CO2. For the Engine exit: Priority I species - SO3:SO2 ratio, SO3, SO2,H2SO4, and particulates; Priority II species: OH,HO2, H2O2, and O; Priority III species - NO, NO2, HONO, and HNO3; and Priority IV species - CO and CO2. Table I summarizes the anticipated concentration range of each of these species. For particulate matter, the quantities of interest are the number density, size distribution, and composition. In order to provide data for validating multidimensional reacting flow models, it would be desirable to make 2-D, time-resolved measurements of the concentrations of the above species and

  13. Aluminum dialkyl phosphinate flame retardants and their hydrolysates: analytical method and occurrence in soil and sediment samples from a manufacturing site.

    PubMed

    Niu, Yumin; Liu, Jingfu; Liang, Yong; Hao, Zhineng; Liu, Jiyan; Liu, Yuchen; Sun, Xue

    2014-03-18

    Aluminum dialkyl phosphinates (ADPs) are emerging phosphorus flame retardants due to their superior characteristics, but their analytical method, and occurrence and fate in environments have never been reported. For the first time, we developed a method for the analysis of trace ADPs and their hydrolysates (dialkyl phosphinic acids, DPAs), and studied their occurrences and fates in soils and sediments. We found that ADPs are hardly dissolved in water and organic solvents, but are dissolved and hydrolyzed to DPAs in 30 mM NH3·H2O, thus both ADPs and DPAs can be determined by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) in the form of DPAs. ADPs and DPAs in soil and sediment samples were determined by (i) extracting both ADPs and DPAs with 75 mM NH3 · H2O, and selectively extract DPAs only with formic acid-water-methanol (5:5:90, v/v/v); (ii) quantifying the total content of ADPs and DPAs, and DPAs by LC-MS/MS analysis of the DPA contents in the former and the latter extract, respectively; and (iii) calculating ADPs from the content difference between the former and the latter extracts. The limit of quantifications (LOQs) of the proposed method were 0.9-1.0 μg/kg, and the mean recoveries ranged from 69.0% to 112.4% with relative standard deviations ≤ 21% (n = 6). In soil and sediment samples around a manufacturing plant, ADPs and DPAs were detected in surface soils in the ranges of 3.9-1279.3 and 1.0-448.6 μg/kg, respectively. While ADPs were found in all the samples of the soil and sediment cores from the drain outlet and the waste residue treatment site at levels ranging from 30.8 to 4628.0 μg/kg, DPAs were found in more than 90% of these samples with concentrations in the range of 1.1-374.6 μg/kg. The occurrences of ADPs and DPAs are not in correlation with the total organic carbon, whereas the occurrences of DPAs are highly correlated with the sample pH. Our study also suggests that the DPAs in the samples sourced

  14. Ubiquitous production of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in global marine environments: a new source indicator for brGDGTs

    NASA Astrophysics Data System (ADS)

    Xiao, Wenjie; Wang, Yinghui; Zhou, Shangzhe; Hu, Limin; Yang, Huan; Xu, Yunping

    2016-10-01

    Presumed source specificity of branched glycerol dialkyl glycerol tetraethers (brGDGTs) from bacteria thriving in soil/peat and isoprenoid GDGTs (iGDGTs) from aquatic organisms led to the development of several biomarker proxies for biogeochemical cycle and paleoenvironmental reconstructions. However, recent studies reveal that brGDGTs are also produced in aquatic environments besides soils and peat. Here we examined three cores from the Bohai Sea, and found distinct difference in brGDGT compositions varying with the distance from the Yellow River mouth. We thus propose an abundance ratio of hexamethylated to pentamethylated brGDGT (IIIa / IIa) to evaluate brGDGT sources. The compilation of globally distributed 1354 marine sediments and 589 soils shows that the IIIa / IIa ratio is generally < 0.59 in soils and 0.59-0.92 and > 0.92 in marine sediments with and without significant terrestrial inputs, respectively. Such disparity confirms the existence of two sources for brGDGTs, a terrestrial origin with lower IIIa / IIa and a marine origin with higher IIIa / IIa, which is likely attributed to a generally higher pH and the production of brGDGTs in cold deep water in marine waters. The application of the IIIa / IIa ratio to the East Siberian Arctic Shelf proves it to be a sensitive source indicator for brGDGTs, which is helpful for accurate estimation of organic carbon source and paleoclimates in marine settings.

  15. Automated solid phase extraction, on-support derivatization and isotope dilution-GC/MS method for the detection of urinary dialkyl phosphates in humans.

    PubMed

    De Alwis, G K Hemakanthi; Needham, Larry L; Barr, Dana B

    2009-01-15

    We developed an analytical method based on solid phase extraction, on-support derivatization and isotope dilution-GC/MS for the detection of dialkyl phosphate (DAP) metabolites, dimethyl thiophosphate, diethyl thiophosphate, dimethyl dithiophosphate, and diethyl dithiophosphate in human urine. The sample preparative procedure is simple and fully automated. In this method, the analytes were extracted from the urinary matrix onto a styrene-divinyl benzene polymer-based solid phase extraction cartridge and derivatized on-column with pentafluorobenzyl bromide. The ester conjugated analytes are eluted from the column with acetonitrile, concentrated and analyzed. Compared to extraction-post extraction derivatization methods for the analysis of DAP metabolites, this on-support derivatization is fast, efficient, and less labor-intensive. Furthermore, it has fewer steps in the sample preparation, uses less solvent and produces less interference. The method is highly sensitive with limits of detection for the analytes ranging from 0.1 to 0.3 ng/mL. The recoveries were high and comparable with those of our previous method. Relative standard deviation, indicative of the repeatability and precision of the method, was 1-17% for the metabolites.

  16. Impact of chain length on antibacterial activity and hemocompatibility of quaternary N-alkyl and n,n-dialkyl chitosan derivatives.

    PubMed

    Sahariah, Priyanka; Benediktssdóttir, Berglind E; Hjálmarsdóttir, Martha Á; Sigurjonsson, Olafur E; Sørensen, Kasper K; Thygesen, Mikkel B; Jensen, Knud J; Másson, Már

    2015-05-11

    A highly efficient method for chemical modification of chitosan biopolymers by reductive amination to yield N,N-dialkyl chitosan derivatives was developed. The use of 3,6-O-di-tert-butyldimethylsilylchitosan as a precursor enabled the first 100% disubstitution of the amino groups with long alkyl chains. The corresponding mono N-alkyl derivatives were also synthesized, and all the alkyl compounds were then quaternized using an optimized procedure. These well-defined derivatives were studied for antibacterial activity against Gram positive S. aureus, E. faecalis, and Gram negative E. coli, P. aeruginosa, which could be correlated to the length of the alkyl chain, but the order was dependent on the bacterial strain. Toxicity against human red blood cells and human epithelial Caco-2 cells was found to be proportional to the length of the alkyl chain. The most active chitosan derivatives were found to be more selective for killing bacteria than the quaternary ammonium disinfectants cetylpyridinium chloride and benzalkonium chloride, as well as the antimicrobial peptides melittin and LL-37.

  17. Effect of successive alkylation of N,N-dialkyl amides on the complexation behavior of uranium and thorium: solvent extraction, small angle neutron scattering, and computational studies.

    PubMed

    Verma, Parveen Kumar; Pathak, Priyanath N; Kumari, Neelam; Sadhu, Biswajit; Sundararajan, Mahesh; Aswal, Vinod Kumar; Mohapatra, Prasanta Kumar

    2014-12-11

    The effect of successive alkylation of the Cα atom adjacent to the carbonyl group in N,N-dialkyl amides (i.e., di(2-ethylhexyl)acetamide (D2EHAA), di(2-ethylhexyl)propionamide (D2EHPRA), di(2-ethylhexyl)isobutyramide (D2EHIBA), and di(2-ethylhexyl)pivalamide (D2EHPVA)) on the extraction behavior of hexavalent uranium (U(VI)) and tetravalent thorium (Th(IV)) ions has been investigated. These studies show that the extraction of Th(IV) is significantly suppressed compared to that of U(VI) with increased branching at the Cα atom adjacent to the carbonyl group. Small angle neutron scattering (SANS) studies showed an increased aggregation tendency in the presence of nitric acid and metal ions. D2EHAA showed more aggregation compared to its branched homologues, which explains its capacity for higher extraction of metal ions. These experimental observations were further supported by density function theory calculations, which provided structural evidence of differential binding affinities of these extractants for uranyl cations. The complexation process is primarily controlled by steric and electronic effects. Quantum chemical calculations showed that local hardness and polarizability can be extremely useful inputs for designing novel extractants relevant to a nuclear fuel cycle.

  18. Chemistry Rocks: Redox Chemistry as a Geologic Tool.

    ERIC Educational Resources Information Center

    Burns, Mary Sue

    2001-01-01

    Applies chemistry to earth science, uses rocks in chemistry laboratories, and teaches about transition metal chemistry, oxidation states, and oxidation-reduction reactions from firsthand experiences. (YDS)

  19. The Chemistry of Precursors to Silicon Carbide.

    DTIC Science & Technology

    1988-03-25

    chains, occur in the decompositions of . dialkyl and higher alkylsubstituted monosilanes . 6) Alkyl substitution for H in monosilanes increases...decomposition activation energies by about 4 ± I Kcal/R groulp up to R 2SiH 2 (i.e. the order of thermal stabilities in monosilanes is SiH 4 < RSiH 3 < R

  20. Constitutional dynamic chemistry: bridge from supramolecular chemistry to adaptive chemistry.

    PubMed

    Lehn, Jean-Marie

    2012-01-01

    Supramolecular chemistry aims at implementing highly complex chemical systems from molecular components held together by non-covalent intermolecular forces and effecting molecular recognition, catalysis and transport processes. A further step consists in the investigation of chemical systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, thus behaving as programmed chemical systems. Supramolecular chemistry is intrinsically a dynamic chemistry in view of the lability of the interactions connecting the molecular components of a supramolecular entity and the resulting ability of supramolecular species to exchange their constituents. The same holds for molecular chemistry when the molecular entity contains covalent bonds that may form and break reversibility, so as to allow a continuous change in constitution by reorganization and exchange of building blocks. These features define a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels.CDC introduces a paradigm shift with respect to constitutionally static chemistry. The latter relies on design for the generation of a target entity, whereas CDC takes advantage of dynamic diversity to allow variation and selection. The implementation of selection in chemistry introduces a fundamental change in outlook. Whereas self-organization by design strives to achieve full control over the output molecular or supramolecular entity by explicit programming, self-organization with selection operates on dynamic constitutional diversity in response to either internal or external factors to achieve adaptation.The merging of the features: -information and programmability, -dynamics and reversibility, -constitution and structural diversity, points to the emergence of adaptive and evolutive chemistry, towards a chemistry of complex matter.

  1. USSR Report, Chemistry.

    DTIC Science & Technology

    2007-11-02

    This chemistry Report from the USSR contains articles mainly on Adsorption, Analytical Chemistry, Biochemistry, Catalysis, Chemical Industry, Coal ... Gasification , Electrochemistry, Fertilizers, Food Technology, Inorganic Compounds, Nitrogen Compounds and Organometallic Compounds.

  2. Chemistry for Potters.

    ERIC Educational Resources Information Center

    Denio, Allen A.

    1980-01-01

    Relates pottery making to chemistry by providing chemical information about clay, its origin, composition, properties, and changes that occur during firing; also describes glaze compositions, examples of redox chemistry, salt glazing, crystalline glazes, and problems in toxicity. (CS)

  3. Organometallic Chemistry of Molybdenum.

    ERIC Educational Resources Information Center

    Lucas, C. Robert; Walsh, Kelly A.

    1987-01-01

    Suggests ways to avoid some of the problems students have learning the principles of organometallic chemistry. Provides a description of an experiment used in a third-year college chemistry laboratory on molybdenum. (TW)

  4. Special Report: Brain Chemistry.

    ERIC Educational Resources Information Center

    Krassner, Michael B.

    1983-01-01

    Chemical actions in the brain result in cognitive, emotional, neuroendocrine, neuromuscular, and/or neurocirculatory effects. Developments in understanding brain chemistry are discussed, considering among others, neurotransmitter chemistry, neuropeptides, drugs and the brain, antidepressants, and actions of minor tranquilizers. (JN)

  5. Environmental chemistry: Volume A

    SciTech Connect

    Yen, T.F.

    1999-08-01

    This is an extensive introduction to environmental chemistry for engineering and chemical professionals. The contents of Volume A include a brief review of basic chemistry prior to coverage of litho, atmo, hydro, pedo, and biospheres.

  6. School Chemistry vs. Chemistry in Research: An Exploratory Experiment.

    ERIC Educational Resources Information Center

    Habraken, Clarisse L.; Buijs, Wim; Borkent, Hens; Ligeon, Willy; Wender, Harry; Meijer, Marijn

    2001-01-01

    Reports on a study exploring why students are not studying chemistry. Three groups of graduating high school students and their chemistry teachers stayed at a research institute working on molecular modeling and wrote essays on school chemistry versus chemistry in research. Concludes that school chemistry does not convey today's chemistry in…

  7. Chemistry on Stamps.

    ERIC Educational Resources Information Center

    Schreck, James O.

    1986-01-01

    Suggests how postage stamps can be incorporated into chemistry teaching. Categories considered include emergence of chemistry as a science, metric system, atoms (and molecules and ions), stoichiometry, energy relationships in chemical systems, chemical bonding, nuclear chemistry, biochemistry, geochemistry, matter (gases, liquids, and solids),…

  8. Green Chemistry and Education.

    ERIC Educational Resources Information Center

    Hjeresen, Dennis L.; Schutt, David L.; Boese, Janet M.

    2000-01-01

    Many students today are profoundly interested in the sustainability of their world. Introduces Green Chemistry and its principles with teaching materials. Green Chemistry is the use of chemistry for pollution prevention and the design of chemical products and processes that are environmentally benign. (ASK)

  9. Teaching School Chemistry.

    ERIC Educational Resources Information Center

    Waddington, D. J., Ed.

    This eight-chapter book is intended for use by chemistry teachers, curriculum developers, teacher educators, and other key personnel working in the field of chemical education. The chapters are: (1) "The Changing Face of Chemistry" (J. A. Campbell); (2) "Curriculum Innovation in School Chemistry" (R. B. Ingel and A. M.…

  10. Chemistry and Art.

    ERIC Educational Resources Information Center

    Berry, Martyn

    1999-01-01

    Describes a Chemistry and Art project developed for secondary students and teachers sponsored by the National Gallery and The Royal Society of Chemistry in the United Kingdom. Discusses aspects of the techniques used in creating five paintings as well as the chemistry involved in their making, deterioration, conservation, and restoration.…

  11. Chemistry as General Education

    ERIC Educational Resources Information Center

    Tro, Nivaldo J.

    2004-01-01

    The efficacy of different science and chemistry courses for science-major and non-major students, and the question of chemistry's contribution to general education are evaluated. Chemistry and science curriculum are too profession- and consumer-oriented, and to overcome this problem, it is advised that all disciplines must incorporate the major…

  12. Mechanisms in Photographic Chemistry

    ERIC Educational Resources Information Center

    Sahyun, M. R. V.

    1974-01-01

    Reviews current research interests in photographic chemistry, involving two proposed models for spectral sensitization of crystal defects and impurities in the photolysis reactivity and the mechanisms of development and complexation. Establishment of photographic chemistry in a chemistry curriculum is recommended. (CC)

  13. Chemistry as General Education

    NASA Astrophysics Data System (ADS)

    Tro, Nivaldo J.

    2004-01-01

    Science courses are common in most general education requirements. This paper addresses the role of chemistry classes in meeting these requirements. Chemistry professors have for many years questioned the appropriateness of the standard introductory chemistry course as general education, resulting in the growing popularity of specialized non-majors courses. I suggest that current non-major chemistry courses cover too much consumer chemistry and ignore some of the big contributions of chemistry to human knowledge. Majors chemistry courses, while they prepare students for majoring in science, do not address these issues either. Consequently, chemistry courses are often an ineffective and unpopular way to meet general education science requirements. Part of the reason for this dilemma is the lack of chemists who address the contributions of chemistry to human knowledge in general. I propose that faculty at liberal arts colleges engage in this important task and that non-majors chemistry textbooks incorporate questions and issues that relate chemistry to a broader view of human knowledge. If these things happen, perhaps chemistry courses will become more effective as general education.

  14. 1,3-dialkyl-8-N-substituted benzyloxycarbonylamino-9-deazaxanthines as potent adenosine receptor ligands: Design, synthesis, structure-affinity and structure-selectivity relationships.

    PubMed

    Fernández, Franco; Caamaño, Olga; Isabel Nieto, M; López, Carmen; García-Mera, Xerardo; Stefanachi, Angela; Nicolotti, Orazio; Isabel Loza, M; Brea, Jose; Esteve, Cristina; Segarra, Victor; Vidal, Bernat; Carotti, Angelo

    2009-05-15

    A number of 1,3-dialkyl-9-deazaxanthines (9-dAXs), bearing a variety of N-substituted benzyloxycarbonylamino substituents at position 8, were prepared and evaluated for their binding affinity to the recombinant human adenosine receptors (hARs), chiefly to the hA(2B) and hA(2A) AR subtypes. Several ligands endowed with excellent binding affinity to the hA(2B) receptors, but low selectivity versus hA(2A) and hA(1) were identified. Among these, 1,3-dimethyl-N-3'-thienyl carbamate 15 resulted as the most potent ligand at hA(2B) (K(i)=0.8 nM), with a low selectivity versus hA(2A) (hA(2A)/hA(2B)=12.6) and hA(1) (hA(1)/hA(2B)=12.5) and a higher selectivity versus hA(3) (hA(3)/hA(2B)=454). When tested in functional assays in vitro, compound 15 exhibited high antagonist activities and efficacies versus both the A(2A) and A(2B) receptor subtypes, with pA(2) values close to the corresponding pK(i)s. A comparative analysis of structure-affinity and structure-selectivity relationships of the similar analogues 8-N-substituted benzyloxycarbonylamino- and 8-N-substituted phenoxyacetamido-9-dAXs suggested that their binding modes at the hA(2B) and hA(2A) ARs may strongly differ. Computational studies help to clarify this striking difference arising from a simple, albeit crucial, structural change, from CH(2)OCON to OCH(2)CON, in the para-position of the 8-phenyl ring.

  15. Seasonal changes in glycerol dialkyl glycerol tetraether concentrations and fluxes in a perialpine lake: Implications for the use of the TEX 86 and BIT proxies

    NASA Astrophysics Data System (ADS)

    Blaga, Cornelia I.; Reichart, Gert-Jan; Vissers, Elisabeth W.; Lotter, André F.; Anselmetti, Flavio S.; Sinninghe Damsté, Jaap S.

    2011-11-01

    To determine where and when glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in lakes are produced, we collected descending particles in Lake Lucerne (Switzerland) using two sediment traps (at 42 and 72 m water depth) with a monthly resolution from January 2008 to late March 2009. Suspended particulate matter (SPM) was monthly filtered from the water column at three different depths. The potential application of GDGTs in palaeoenvironmental and palaeoclimatic reconstructions was investigated by comparing core lipids and their relative GDGT distribution, with lake water temperatures throughout the year. Fluxes of GDGTs and their concentrations in the water column vary according to a seasonal pattern, showing a similar trend in the SPM and sediment traps. Fluxes and concentrations of isoprenoid GDGTs increase with depth, maximum values being observed in the deeper part of the water column, indicating production of isoprenoid GDGTs by Thaumarchaeota in the deep (˜50 m), aphotic zone of Lake Lucerne. The flux-weighted averages of the proxies TEX 86 (0.27) and BIT (0.03) based on the total extracted GDGTs are similar at both trap depths. A sediment core from the same location showed that in the first few centimetres of the core TEX 86 and BIT values of 0.29 and 0.07, respectively, are similar to those recorded for descending particles and SPM, indicating that the sedimentary TEX 86 records the annual mean temperature of deeper waters in Lake Lucerne. TEX 86 values are slightly higher below 20 cm in the core. This offset is interpreted to be caused by the present-day trophic state of the lake, which probably resulted in a deeper niche of the Thaumarchaeota. Branched GDGTs represent only a minor fraction of the total GDGTs in the lake and their origin remains unclear. Our data reveal that GDGTs in lakes have a large potential for palaeoclimatic studies but indicate that knowledge of the system is important for accurate interpretation.

  16. Insights into the biological source and environmental gradients shaping the distribution of H-shaped glycerol dialkyl glycerol tetraethers in Yellowstone National Park geothermal springs

    NASA Astrophysics Data System (ADS)

    Jia, C.; Xie, W.; Wang, J.; Boyd, E. S.; Zhang, C.

    2013-12-01

    Archaea are ubiquitous in natural environments. The unique tetraether lipids in archaeal membranes enable the maintenance of ion permeability across broad environmental gradients. H-shaped isoprenoid glycerol dialkyl glycerol tetraethers (H-GDGTs), in which the two biphytanyl carbon skeletons are covalently bound by a carbon-carbon bond, have been recently identified in both marine and geothermal environments. Here we report the core H-GDGTs (C-H-GDGTs) and polar H-GDGTs (P-H-GDGTs) associated with sediments sampled from geothermal springs in Yellowstone National Park and investigate their abundance in relation to environmental gradients. The abundance of C- and P-H-GDGTs exhibit strong and negative correlation with pH (P = 0.007), suggesting that H-shaped GDGTs help to maintain cell membrane fluidity in acidic environments. Reanalysis of archaeal 16S rRNA gene pyrotags published previously from (Boyd E. Hamilton T. L., Wang J., He L., Zhang C. L. 2013. The role of tetraether lipid composition in the adaptation of thermophilic archaea to acidity. Frontiers in Terrestrial Microbiology. 4: doi: 10.3389/fmicb.2013.00062) indicates that these H-GDGTs are associated with environments dominanted by Thermoplasmatales, which are thermoacidiphiles. Two equations were established to define the relationships between the abundance of H-GDGTs, the abundance of archaeal taxa based on 16S rRNA gene phylogenetic affiliations, and pH. Both equations have high predictive capacity in predicting the distribution of archaeal lipids in the geothermal system. These observations provide new insight into the biological source of H-GDGTs and suggest a prominent role for these lipids in the diversification of archaea into or out of acidic high temperature environments.

  17. Biological Sources of Branched Glycerol Dialkyl Glycerol Tetraethers (brGDGTs) in Terrestrial Hot Springs: A Possible Link Between Nitrogen-cycling Bacteria and brGDGT Production

    NASA Astrophysics Data System (ADS)

    Wang, J. X.; Xie, W.; Boyd, E. S.; Hedlund, B. P.; Zhang, C.

    2014-12-01

    Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are common in peat, soil, lakes, rivers and hot springs. To seek the potential biological sources of brGDGTs in geothermal environments, we investigated 65 hot springs in the Yellowstone National Park (USA) and Tengchong (China). Together with previously published data from hot springs in the Great Basin (USA) and Tibet (China), we found that the abundance of brGDGTs tended to peak in springs with pH > 8. This contrasts with previous observations indicating an abundance of brGDGTs in acidic soils and peat bogs, suggesting a different biological source and function for lipids in these environments. In support of this hypothesis, a comparison of Cyclization ratios of Branched Tetraethers (CBT) between hot springs and surrounding soils indicated that more brGDGTs with cyclopentane moieties were produced in alkaline hot springs than in nearby low-temperature soils. Since Acidobacteria (the likely source of brGDGTs in peat bog environments) tend to have low CBT ratios, these data suggest a different source for brGDGTs in hot spring environments. RDA and regression analysis integrating brGDGT compounds and nitrogen species indicate that Bacteria involved in the nitrogen biogeochemical cycle (ammonia oxidation and nitrite reduction) may be related to the production of brGDGTs in terrestrial hot springs. However, direct evidence showing the link between nitrogen-cycling bacteria and brGDGT production has yet to be demonstrated under laboratory conditions. Nevertheless, our study expands the possibility of brGDGT sources into bacterial communities in terrestrial geothermal systems where Acidobacteria are absent or only a minor component.

  18. Distribution of branched glycerol dialkyl glycerol tetraethers in surface soils of the Qinghai-Tibetan Plateau: implications of brGDGTs-based proxies in cold and dry regions

    NASA Astrophysics Data System (ADS)

    Ding, S.; Xu, Y.; Wang, Y.; He, Y.; Hou, J.; Chen, L.; He, J.-S.

    2015-06-01

    The methylation index of branched tetraethers (MBT) and cyclization ratio of branched tetraethers (CBT) based on the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGT) are useful proxies for the reconstruction of mean annual air temperature (MAT) and soil pH. Recently, a series of 6-methyl brGDGTs were identified which were previously co-eluted with 5-methyl brGDGTs. However, little is known about 6-methyl brGDGTs in the Qinghai-Tibetan Plateau (QTP), a critical region of the global climate system. Here, we analyze 30 surface soils covering a large area of the QTP, among which 6-methyl brGDGTs were the most abundant components (average 53 ± 17% of total brGDGT). The fractional abundance of 6-methyl brGDGTs showed a good correlation with soil pH, while the global MBT'5ME calibration overestimates MAT in the QTP. We therefore proposed a MBT5/6 index including both 5- and 6-methyl brGDGTs, presenting a strong correlation with MAT in QTP: MAT = -20.14 + 39.51 × MBT5/6 (n = 27, r2 = 0.82; RMSE = 1.3 °C). Another index, namely IBT (isomerization of branched tetraether), based on carbon skeleton isomerization of the 5-methyl to 6-methyl brGDGTs, is dependent on soil pH: pH = 6.77 - 1.56 × IBT (n = 27; r2 = 0.74, RMSE = 0.32). Our study suggests that changing the position of methyl group of brGDGTs may be another mechanism for some soil bacteria to adapt to the ambient pH change in addition to the well-known cyclization.

  19. Constitutive Expression of the Cytochrome P450 EthABCD Monooxygenase System Enables Degradation of Synthetic Dialkyl Ethers in Aquincola tertiaricarbonis L108

    PubMed Central

    Schuster, Judith; Purswani, Jessica; Breuer, Uta; Pozo, Clementina; Harms, Hauke; Müller, Roland H.

    2013-01-01

    In Rhodococcus ruber IFP 2001, Rhodococcus zopfii IFP 2005, and Gordonia sp. strain IFP 2009, the cytochrome P450 monooxygenase EthABCD catalyzes hydroxylation of methoxy and ethoxy residues in the fuel oxygenates methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). The expression of the IS3-type transposase-flanked eth genes is ETBE dependent and controlled by the regulator EthR (C. Malandain et al., FEMS Microbiol. Ecol. 72:289–296, 2010). In contrast, we demonstrated by reverse transcription-quantitative PCR (RT-qPCR) that the betaproteobacterium Aquincola tertiaricarbonis L108, which possesses the ethABCD genes but lacks ethR, constitutively expresses the P450 system at high levels even when growing on nonether substrates, such as glucose. The mutant strain A. tertiaricarbonis L10, which is unable to degrade dialkyl ethers, resulted from a transposition event mediated by a rolling-circle IS91-type element flanking the eth gene cluster in the wild-type strain L108. The constitutive expression of Eth monooxygenase is likely initiated by the housekeeping sigma factor σ70, as indicated by the presence in strain L108 of characteristic −10 and −35 binding sites upstream of ethA which are lacking in strain IFP 2001. This enables efficient degradation of diethyl ether, diisopropyl ether, MTBE, ETBE, TAME, and tert-amyl ethyl ether (TAEE) without any lag phase in strain L108. However, ethers with larger residues, n-hexyl methyl ether, tetrahydrofuran, and alkyl aryl ethers, were not attacked by the Eth system at significant rates in resting-cell experiments, indicating that the residue in the ether molecule which is not hydroxylated also contributes to the determination of substrate specificity. PMID:23354715

  20. Principles of Environmental Chemistry

    NASA Astrophysics Data System (ADS)

    Hathaway, Ruth A.

    2007-07-01

    Roy M. Harrison, Editor RSC Publishing; ISBN 0854043713; × + 363 pp.; 2006; $69.95 Environmental chemistry is an interdisciplinary science that includes chemistry of the air, water, and soil. Although it may be confused with green chemistry, which deals with potential pollution reduction, environmental chemistry is the scientific study of the chemical and biochemical principles that occur in nature. Therefore, it is the study of the sources, reactions, transport, effects, and fates of chemical species in the air, water, and soil environments, and the effect of human activity on them. Environmental chemistry not only explores each of these environments, but also closely examines the interfaces and boundaries where the environments intersect.

  1. Microwave-accelerated preparation and analytical characterization of 5-ethoxy-N,N-dialkyl-[α,α,β,β-H(4) ]- and [α,α,β,β-D(4) ]-tryptamines.

    PubMed

    Tearavarich, Ruchanok; Hahnvajanawong, Viwat; Dempster, Nicola; Daley, Paul F; Cozzi, Nicholas V; Brandt, Simon D

    2011-09-01

    The increased interest in N,N-dialkyl tryptamines is a reflection of their diverse range of biologically active properties. Deuterated derivatives are of interest for use as internal standards in bioanalytical or pharmacological assays. The present study reports on the synthesis of twelve novel 5-ethoxy-N,N-dialkyl-[α,α,β,β-H(4) ]-tryptamines and their [α,α,β,β-D(4) ]-counterparts following the Speeter and Anthony procedure. The normally time-consuming reduction step was carried out in 5 min under microwave-accelerated conditions. Good yields were obtained using tetrahydrofuran as the solvent at 150 °C. The resulting 24 tryptamines have been characterized by 1D/2D nuclear magnetic resonance spectroscopy and gas chromatography ion trap mass spectrometry. Differential fragmentation of side-chain-related iminium ions has been observed as a key principle. Because many N,N-dialkyltryptamines are available outside of traditional pharmaceutical supply chains as so-called 'research chemicals', the availability, as standards, of these new N,N-dialkyltryptamines will aid in identifiying novel tryptamines arising from these other souces. They should therefore be of immediate value within forensic, research, and public health contexts.

  2. Green Chemistry Pedagogy

    NASA Astrophysics Data System (ADS)

    Kolopajlo, Larry

    2017-02-01

    This chapter attempts to show how the practice of chemistry teaching and learning is enriched by the incorporation of green chemistry (GC) into lectures and labs. To support this viewpoint, evidence from a wide range of published papers serve as a cogent argument that GC attracts and engages both science and nonscience students, enhances chemistry content knowledge, and improves the image of the field, while preparing the world for a sustainable future. Published pedagogy associated with green and sustainable chemistry is critically reviewed and discussed.

  3. Connecting Algebra and Chemistry.

    ERIC Educational Resources Information Center

    O'Connor, Sean

    2003-01-01

    Correlates high school chemistry curriculum with high school algebra curriculum and makes the case for an integrated approach to mathematics and science instruction. Focuses on process integration. (DDR)

  4. USSR Report, Chemistry.

    DTIC Science & Technology

    2007-11-02

    Industry, Coal Gasification , Electrochemistry, Inorganic Compounds, Nitrogen Compounds, Organophosphorus Compounds, Petroleum Processing Technology, Pharmacology and Toxicology, Polymers and Polymerization and, Radiation Chemistry.

  5. Science Update: Analytical Chemistry.

    ERIC Educational Resources Information Center

    Worthy, Ward

    1980-01-01

    Briefly discusses new instrumentation in the field of analytical chemistry. Advances in liquid chromatography, photoacoustic spectroscopy, the use of lasers, and mass spectrometry are also discussed. (CS)

  6. The synthesis, characterization, and structure-property relationships of regioregular 4,4'-dialkyl-2,2'-bithiazole oligomers and polymers

    NASA Astrophysics Data System (ADS)

    Nanos, John I.

    2005-12-01

    The 4,4'-dialkyl-2,2'-bithiazole moiety can be efficiently coupled to produce well-defined oligomers or block co-oligomers via Stille reactions of mono-bromo and tin substituted precursors. Dehalogenative polycondensations produce high molecular weight homo-polymers and Stille coupling of dibromo and di-tin monomers yields alternating copolymers. The symmetry of the bithiazole monomeric unit produces regioregular oligomers and polymers with the HH-TT dyad sequence. Model compound oligomers were synthesized and studied to explore the progression of structure property relationships with main chain extension. DSC measurements indicate the potential presence of at least three phases in solution cast thin films---the disordered isotropic melt, a stable low temperature morphology designated the alpha-phase, and a high temperature meta-stable morphology designated the beta-phase. Melt transition temperatures are inversely proportional to side alkyl chain length and directly proportional to main chain length and the interplay between the two effects greatly influences the observed thermochromism. Temperature dependent IR studies show an increase in the gauche conformations of the side chains at the low temperature alpha-beta phase transition and main chain twisting at the beta-isotropic transition. The onset of side chain and main chain motion at these phase transition temperatures was confirmed with variable temperature solid state NMR. Temperature dependent XRD results indicate the presence of a solid-to-solid crystal phase change at the low temperature transition followed by formation of preferred orientations of the beta and alpha ordered phases upon cooling from the isotropic melt. The solid-to-solid crystal phase transition is triggered by the increased motion of the side chains, and the magnitude of the intermolecular side chain packing forces dictate if the transitions occur cooperatively (observed isosbestic point) or as isolated events. Comparison with the 3

  7. Provenance of tetraether membrane lipids in a large temperate lake (Loch Lomond, UK): implications for glycerol dialkyl glycerol tetraether (GDGT)-based palaeothermometry

    NASA Astrophysics Data System (ADS)

    Buckles, L. K.; Weijers, J. W. H.; Tran, X.-M.; Waldron, S.; Sinninghe Damsté, J. S.

    2014-10-01

    The application of glycerol dialkyl glycerol tetraether (GDGT)-based palaeoenvironmental proxies, such as the branched vs. isoprenoidal tetratether (BIT) index, TEX86 and the MBT-CBT palaeothermometer, has lately been expanded to lacustrine sediments. Given recent research identifying the production of branched, bacterial GDGTs (brGDGTs) within lakes, it is necessary to ascertain the effect of this lacustrine production on GDGT-based proxies. This study profiles a temperate, monomictic lake (Loch Lomond, UK), analysing labile intact polar GDGT lipids (IPLs) and resilient core GDGT lipids (CLs) in catchment soils, small tributary rivers, lake water and lake sediments. Loch Lomond consists of two basins bisected by the Highland Boundary Fault, resulting in a mesotrophic to oligotrophic gradient from south to north. The north basin is fjord-like, while the south basin is shallow with a lowland catchment. Besides abundant influxes of allochthonous soil- and peat-derived (CL) brGDGTs, brGDGTs are produced in a variety of settings in Loch Lomond. Rather than integrating a scattered soil signal, there is some evidence that small rivers may contribute to the brGDGT pool through addition of brGDGTs produced in situ in these streams. Three hundred days of settling particles and water column profiles of suspended particulate matter (SPM; March and September 2011) reveal brGDGT production throughout the water column, with (IPL and CL) brGDGT distributions varying by basin. In lake sediments, in situ brGDGT production affects the distributions of sedimentary brGDGTs despite high soil- and peat-derived organic matter influxes from the catchment. MBT-CBT-derived mean annual air temperature (MAAT) estimates from soil, river and lake sediments vary widely. A strong bias towards higher MAATs in the south and lower MAATs in the north basin further complicates the application of the proxy. These results emphasise that caution must be exercised when applying the MBT

  8. Distributions of glycerol dialkyl glycerol tetraethers in surface soils of Qinghai-Tibetan Plateau: implications of GDGT-based proxies in cold and dry regions

    NASA Astrophysics Data System (ADS)

    Ding, S.; Xu, Y.; Wang, Y.; He, Y.; Hou, J.; Chen, L.; He, J.-S.

    2015-01-01

    The methylation index of branched tetraethers (MBT) and cyclization ratio of branched tetraethers (CBT) based on the distribution of bacteria-derived branched glycerol dialkyl glycerol tetraethers (bGDGTs) are useful proxies for the reconstruction of continental paleotemperature and soil pH. Several calibrations of the MBT-CBT index have been proposed based on global and regional soils and lake sediments. However, little is known about the distribution and applicability of GDGTs proxies in the Qinghai-Tibet Plateau (QTP), a critical region of the global climate system. Here, we investigated 33 surface soils covering a large area of the QTP. Redundancy analysis showed that soil pH was the most important factor affecting GDGT distributions, followed by mean annual precipitation (MAP) and mean annual air temperature (MAT). The branched-isoprenoid tetraether (BIT) index, an indicator for estimation of soil organic matter in aquatic environments, varied from 0.48 to 1 and negatively correlated with soil pH (r2 = 0.38), suggesting that the BIT index should be used with caution in the QTP. A transfer function of the CBT index-soil pH was established to estimate paleo-soil pH in the QTP: pH = 8.33-1.43 × CBT (r2 = 0.80, RMSE = 0.27 pH unit). The local calibration of MBT-CBT index presented a weak, still significant correlation with MAT (r2 = 0.36) mainly owing to the additional influence of MAP (r2 = 0.50). Combining our data with previously reported GDGTs for Chinese soils resulted in a new calibration of MBT/CBT-MAT: MAT = 2.68+26.14 × MBT-3.37 × CBT (r2 = 0.73; RMSE = 4.2 °C, n = 164). The correlation coefficient and residual error of this new transfer function is comparable with global calibrations, suggesting that MBT-CBT paleotemperature proxy is still valid in the QTP.

  9. A Crystallizable dinuclear tuck-in-tuck-over tuck-over dialkyl Tren uranium complex and double dearylation of BPh(4)(-) to give the BPh(2)-functionalized metallocycle [U{N(CH(2)CH(2)NSiMe(3))(2)(CH(2)CH(2)NSiMe(2)CHBPh(2))}(THF)].

    PubMed

    Gardner, Benedict M; McMaster, Jonathan; Lewis, William; Blake, Alexander J; Liddle, Stephen T

    2009-08-05

    The unprecedented formation of a dinuclear tuck-in-tuck-over tuck-over dialkyl Tren-uranium(IV) complex and the first example of double dearylation of BPh(4)(-) in a molecular context to give a BPh(2)-functionalized uranium metallocycle are reported.

  10. Bioorganic and bioinorganic chemistry.

    PubMed

    Constable, Edwin C; Housecroft, Catherine E; Creus, Marc; Gademann, Karl; Giese, Bernd; Ward, Thomas R; Woggon, Wolf D; Chougnet, Antoinette

    2010-01-01

    The interdisciplinary projects in bioinorganic and bioorganic chemistry of the Department of Chemistry, University of Basel led to the preparation of new systems that mimic biologically important processes and to the discovery of compounds from natural sources which are very promising with respect to medical applications. The advances in these areas are reported here.

  11. Coupled Phenomena in Chemistry.

    ERIC Educational Resources Information Center

    Matsubara, Akira; Nomura, Kazuo

    1979-01-01

    Various phenomena in chemistry and biology can be understood through Gibbs energy utilization. Some common phenomena in chemistry are explained including neutralization, hydrolysis, oxidation and reaction, simultaneous dissociation equilibrium of two weak acids, and common ion effect on solubility. (Author/SA)

  12. Chemistry and Philosophy

    ERIC Educational Resources Information Center

    Theobald, D. W.

    1970-01-01

    In the second article of a series, the author discusses some of the interactions between chemistry and philosophy. Evaluates chemistry's role within the scientific enterprise. Traces the rise and fall of the logical atom and argues for a new way of looking at science as an educational instrument. (RR)

  13. Chemistry from Issues.

    ERIC Educational Resources Information Center

    Harding, Jan; Donaldson, Jim

    1986-01-01

    Describes the "Chemistry from Issues" project at Chelsea College. Provides the background information, rationale, and overall structure of a proposed course about the importance of chemistry to common culture. Outlines one module about the British steel industry that has been taught at King's College. (TW)

  14. Infrared Lasers in Chemistry.

    ERIC Educational Resources Information Center

    John, Phillip

    1982-01-01

    Selected infrared laser chemistry topics are discussed including carbon dioxide lasers, infrared quanta and molecules, laser-induced chemistry, structural isomerization (laser purification, sensitized reactions, and dielectric breakdown), and fundamental principles of laser isotope separation, focusing on uranium isotope separation. (JN)

  15. Chemistry in Microfluidic Channels

    ERIC Educational Resources Information Center

    Chia, Matthew C.; Sweeney, Christina M.; Odom, Teri W.

    2011-01-01

    General chemistry introduces principles such as acid-base chemistry, mixing, and precipitation that are usually demonstrated in bulk solutions. In this laboratory experiment, we describe how chemical reactions can be performed in a microfluidic channel to show advanced concepts such as laminar fluid flow and controlled precipitation. Three sets of…

  16. Pre-Tech Chemistry.

    ERIC Educational Resources Information Center

    Florida Junior Coll., Jacksonville.

    This course guide is designed to aid chemistry instructors in teaching the skills and knowledge needed by those students planning to take junior college chemistry and is composed of 11 terminal performance objectives, with intermediate performance objectives and sample criterion measures. Suggestions for related laboratory activities are also…

  17. Brushing Up on Chemistry.

    ERIC Educational Resources Information Center

    Trantow, Ashley

    2002-01-01

    Presents an activity designed for use during National Chemistry Week 2002 with the theme "Chemistry Keeps Us Clean". Allows students to discover more about a cleaning product they use everyday. Students make their own toothpaste and compare its properties with those of commercial toothpaste. (MM)

  18. Movies in Chemistry Education

    ERIC Educational Resources Information Center

    Pekdag, Bulent; Le Marechal, Jean-Francois

    2010-01-01

    This article reviews numerous studies on chemistry movies. Movies, or moving pictures, are important elements of multimedia and signify a privileged or motivating means of presenting knowledge. Studies on chemistry movies show that the first movie productions in this field were devoted to university lectures or documentaries. Shorter movies were…

  19. Chemistry of Moth Repellents

    ERIC Educational Resources Information Center

    Pinto, Gabriel

    2005-01-01

    An effective way to teach chemistry is to examine the substances used in daily life from a pedagogical viewpoint, from the overlap of science, technology, and society (STS). A study aims to engage students in the topic of moth repellents and to encourage them to investigate the chemistry in this familiar product using a set of questions.

  20. Mathematics and Chemistry

    ERIC Educational Resources Information Center

    Henson, R.; Stumbles, A.

    1977-01-01

    The relationship between mathematics and chemistry has been changing rapidly in recent years. Some chemistry teachers have experienced difficulties in their teaching with the introduction of modern mathematics in the schools. Some suggestions for reinforcing the concepts and language of modern mathematics are put forth. (Author/MA)

  1. Organic Chemistry Made Easy.

    ERIC Educational Resources Information Center

    Bradt, Steve

    1998-01-01

    Student-led workshops are helping undergraduate students learn from each other as they tackle organic chemistry. Each week, small groups brainstorm tough problems in sessions guided by upper-class students who have taken and passed the course. Debating and discussing chemistry problems with peers engages students with the material and boosts…

  2. Undergraduate Chemistry Laboratory

    ERIC Educational Resources Information Center

    Bretz, Stacey Lowery; Fay, Michael; Bruck, Laura B.; Towns, Marcy H.

    2013-01-01

    Forty chemistry faculty from American Chemical Society-approved departments were interviewed to determine their goals for undergraduate chemistry laboratory. Faculty were stratified by type of institution, departmental success with regard to National Science Foundation funding for laboratory reform, and level of laboratory course. Interview…

  3. Biosynthetic inorganic chemistry.

    PubMed

    Lu, Yi

    2006-08-25

    Inorganic chemistry and biology can benefit greatly from each other. Although synthetic and physical inorganic chemistry have been greatly successful in clarifying the role of metal ions in biological systems, the time may now be right to utilize biological systems to advance coordination chemistry. One such example is the use of small, stable, easy-to-make, and well-characterized proteins as ligands to synthesize novel inorganic compounds. This biosynthetic inorganic chemistry is possible thanks to a number of developments in biology. This review summarizes the progress in the synthesis of close models of complex metalloproteins, followed by a description of recent advances in using the approach for making novel compounds that are unprecedented in either inorganic chemistry or biology. The focus is mainly on synthetic "tricks" learned from biology, as well as novel structures and insights obtained. The advantages and disadvantages of this biosynthetic approach are discussed.

  4. Art in Chemistry; Chemistry in Art.

    ERIC Educational Resources Information Center

    Greenberg, Barbara R.; Patterson, Dianne

    High school teachers are often challenged to motivate students who have little or no interest in a subject and are bored with traditional instruction. This unique book is designed to help educators make chemistry classes more interesting and links art curriculum to practical applications, integrating the two subjects through scores of hands-on…

  5. Korean Kimchi Chemistry: A Multicultural Chemistry Connection

    ERIC Educational Resources Information Center

    Murfin, Brian

    2009-01-01

    Connecting science with different cultures is one way to interest students in science, to relate science to their lives, and at the same time to broaden their horizons in a variety of ways. In the lesson described here, students make kimchi, a delicious and popular Korean dish that can be used to explore many important chemistry concepts,…

  6. EVOLVING FROM GREEN CHEMISTRY TO SUSTAINABLE CHEMISTRY

    EPA Science Inventory

    The twelve principles of green chemistry provide a foundation and pathway which allows researchers to incorporate greenness into existing reactions or when developing new technologies. Research from our laboratory has adopted many of these principles and utlizes them as a major c...

  7. Environmental chemistry. 5th edition

    SciTech Connect

    Manahan, S.E. . Dept. of Chemistry)

    1991-01-01

    This book is organized around several major sections: aquatic Chemistry, atmospheric chemistry, the geosphere and hazardous wastes, toxicological chemistry, and resources and energy. Specific topics discussed in the book include a general introduction to environment chemistry, basic principles of aquatic chemistry, water pollution and water treatment, the essential role of microorganisms in aquatic chemical phenomena, atmospheric chemistry, a discussion of major threats to the global atmosphere (particularly greenhouse gases and ozone-depleting chemicals), the geosphere and hazardous substances, soil chemistry, and the nature and sources of hazardous wastes. The environmental chemistry of hazardous wastes, their treatment, minimization, and recycling, and the effects of these hazardous substances in also presented.

  8. Moderator Chemistry Program

    SciTech Connect

    Dewitt, L.V.; Gibbs, A.; Lambert, D.P.; Bohrer, S.R.; Fanning, R.L.; Houston, M.W.; Stinson, S.L.; Deible, R.W.; Abdel-Khalik, S.I.

    1990-11-01

    Over the past fifteen months, the Systems Chemistry Group of the Reactor Engineering Department has undertaken a comprehensive study of the Department`s moderator chemistry program at Savannah River Site (SRS). An internal review was developed to formalize and document this program. Objectives were as outlined in a mission statement and action plan. In addition to the mission statement and action plan, nine separate task reports have been issued during the course of this study. Each of these task reports is included in this document as a chapter. This document is an organized compilation of the individual reports issued by the Systems Chemistry Group in assessment of SRS moderator chemistry to determine if there were significant gaps in the program as ft existed in October, 1989. While these reviews found no significant gaps in that mode of operation, or any items that adversely affected safety, items were identified that could be improved. Many of the items have already been dear with or are in the process of completion under this Moderator Chemistry Program and other Reactor Restart programs. A complete list of the items of improvement found under this assessment is found in Chapter 9, along with a proposed time table for correcting remaining items that can be improved for the chemistry program of SRS reactors. An additional external review of the moderator chemistry processes, recommendations, and responses to/from the Reactor Corrosion Mitigation Committee is included as Appendix to this compilation.

  9. Moderator Chemistry Program

    SciTech Connect

    Dewitt, L.V.; Gibbs, A.; Lambert, D.P.; Bohrer, S.R.; Fanning, R.L.; Houston, M.W.; Stinson, S.L.; Deible, R.W.; Abdel-Khalik, S.I.

    1990-11-01

    Over the past fifteen months, the Systems Chemistry Group of the Reactor Engineering Department has undertaken a comprehensive study of the Department's moderator chemistry program at Savannah River Site (SRS). An internal review was developed to formalize and document this program. Objectives were as outlined in a mission statement and action plan. In addition to the mission statement and action plan, nine separate task reports have been issued during the course of this study. Each of these task reports is included in this document as a chapter. This document is an organized compilation of the individual reports issued by the Systems Chemistry Group in assessment of SRS moderator chemistry to determine if there were significant gaps in the program as ft existed in October, 1989. While these reviews found no significant gaps in that mode of operation, or any items that adversely affected safety, items were identified that could be improved. Many of the items have already been dear with or are in the process of completion under this Moderator Chemistry Program and other Reactor Restart programs. A complete list of the items of improvement found under this assessment is found in Chapter 9, along with a proposed time table for correcting remaining items that can be improved for the chemistry program of SRS reactors. An additional external review of the moderator chemistry processes, recommendations, and responses to/from the Reactor Corrosion Mitigation Committee is included as Appendix to this compilation.

  10. Computational quantum chemistry website

    SciTech Connect

    1997-08-22

    This report contains the contents of a web page related to research on the development of quantum chemistry methods for computational thermochemistry and the application of quantum chemistry methods to problems in material chemistry and chemical sciences. Research programs highlighted include: Gaussian-2 theory; Density functional theory; Molecular sieve materials; Diamond thin-film growth from buckyball precursors; Electronic structure calculations on lithium polymer electrolytes; Long-distance electronic coupling in donor/acceptor molecules; and Computational studies of NOx reactions in radioactive waste storage.

  11. Fluorine in medicinal chemistry.

    PubMed

    Swallow, Steven

    2015-01-01

    Since its first use in the steroid field in the late 1950s, the use of fluorine in medicinal chemistry has become commonplace, with the small electronegative fluorine atom being a key part of the medicinal chemist's repertoire of substitutions used to modulate all aspects of molecular properties including potency, physical chemistry and pharmacokinetics. This review will highlight the special nature of fluorine, drawing from a survey of marketed fluorinated pharmaceuticals and the medicinal chemistry literature, to illustrate key concepts exploited by medicinal chemists in their attempts to optimize drug molecules. Some of the potential pitfalls in the use of fluorine will also be highlighted.

  12. Frontiers in analytical chemistry

    SciTech Connect

    Amato, I.

    1988-12-15

    Doing more with less was the modus operandi of R. Buckminster Fuller, the late science genius, and inventor of such things as the geodesic dome. In late September, chemists described their own version of this maxim--learning more chemistry from less material and in less time--in a symposium titled Frontiers in Analytical Chemistry at the 196th National Meeting of the American Chemical Society in Los Angeles. Symposium organizer Allen J. Bard of the University of Texas at Austin assembled six speakers, himself among them, to survey pretty widely different areas of analytical chemistry.

  13. Chemistry in Novae

    NASA Astrophysics Data System (ADS)

    Rawlings, J. M. C.; Williams, D. A.

    It is shown that the 5 μm excess, which is attributed to CO in the ejecta of novae, can be modelled chemically. The principle problems involved in the modelling are: (1) the high ejecta temperature (≡104K), (2) the extremely high UV flux, and (3) the marginal self-shielding capability of H2. The authors find that the condition of H2 self-shielding alone is sufficient to allow rapid chemistry to proceed. Time-dependent chemistry calculations indicate that the chemistry is steered by the physics of the system.

  14. Surface chemistry of InP quantum dots: a comprehensive study.

    PubMed

    Cros-Gagneux, Arnaud; Delpech, Fabien; Nayral, Céline; Cornejo, Alfonso; Coppel, Yannick; Chaudret, Bruno

    2010-12-29

    Advanced (1)H, (13)C, and (31)P solution and solid-state NMR studies combined with IR spectroscopy were used to probe, at the molecular scale, the composition and the surface chemistry of indium phosphide (InP) quantum dots (QDs) prepared via a non-coordinating solvent strategy. This nanomaterial can be described as a core-multishell object: an InP core, with a zinc blende bulk structure, is surrounded first by a partially oxidized surface shell, which is itself surrounded by an organic coating. This organic passivating layer is composed, in the first coordination sphere, of tightly bound palmitate ligands which display two different bonding modes. A second coordination sphere includes an unexpected dialkyl ketone and residual long-chain non-coordinating solvents (ODE and its isomers) which interact through weak intermolecular bonds with the alkyl chains of the carboxylate ligands. We show that this ketone is formed during the synthesis process via a decarboxylative coupling route and provides oxidative conditions which are responsible for the oxidation of the InP core surface. This phenomenon has a significant impact on the photoluminescence properties of the as-synthesized QDs and probably accounts for the failure of further growth of the InP core.

  15. Bis(imino)diphenylamido rare-earth metal dialkyl complexes: synthesis, structure, and catalytic activity in living ring-opening ε-caprolactone polymerization and copolymerization with γ-butyrolactone.

    PubMed

    Du, Gaixia; Wei, Yanling; Zhang, Wei; Dong, Yuping; Lin, Zhengguo; He, Huan; Zhang, Shaowen; Li, Xiaofang

    2013-01-28

    Bis(imino)diphenylamido rare-earth metal dialkyl complexes [o-(2,6-(i)Pr(2)-C(6)H(3)-N=C-C(6)H(4))(2)-N]Ln(CH(2)SiMe(3))(2) (1: Ln = Sc; 2: Ln = Lu; 3: Ln = Y) have been synthesized in good yields and structurally characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction studies. They serve as highly efficient single-component catalysts both for the living ring-opening ε-caprolactone polymerization and random copolymerization with γ-butyrolactone, with the activity being dependent on the steric hindrance around the metal center, yielding high molecular weight PCLs or P(CL-co-BL)s with narrow molecular weight distributions.

  16. Design, synthesis and evaluation of dialkyl 4-(benzo[d][1,3]dioxol-6-yl)-1,4-dihydro-2,6-dimethyl-1-substituted pyridine-3,5-dicarboxylates as potential anticonvulsants and their molecular properties prediction.

    PubMed

    Prasanthi, G; Prasad, K V S R G; Bharathi, K

    2013-08-01

    The present study is on the development of dialkyl 4-(benzo[d][1,3]dioxol-6-yl)-1,4-dihydro-2,6-dimethyl-1-substituted pyridine-3,5-dicarboxylate derivatives as isosteric analogues of isradipine and nifedipine, by the replacement of benzofurazanyl and 2-nitrophenyl groups respectively with benzo[d][1,3]dioxo-6-yl group, as potential anticonvulsants. Fivfteen new derivatives (8a-8o) were synthesized and tested for anticonvulsant activity using maximal electroshock and subcutaneous pentylenetetrazole induced seizure methods. Compound 8f possessing free NH group in 1,4-dihydropyridine ring, diethyl ester functionality at the positions 3 and 5 showed significant anticonvulsant and antioxidant activities. This was also supported by molecular properties prediction data. Selected compounds were evaluated for antinociceptive activity in capsaicin induced nociception assay at 10 mg/kg body weight, but displayed no significant activity at the tested dose.

  17. Water Chemistry: Seeking Information

    ERIC Educational Resources Information Center

    Delfino, Joseph J.

    1977-01-01

    A survey of the available literature in water chemistry is presented. Materials surveyed include: texts, reference books, bibliographic resources, journals, American Chemical Society publications, proceedings, unpublished articles, and reports. (BT)

  18. Uncertainty in chemistry.

    PubMed

    Menger, Fredric M

    2010-09-01

    It might come as a disappointment to some chemists, but just as there are uncertainties in physics and mathematics, there are some chemistry questions we may never know the answer to either, suggests Fredric M. Menger.

  19. Frontiers in Chemistry.

    ERIC Educational Resources Information Center

    Joyce, Robert M., Ed.

    1980-01-01

    This article describes recent progress in chemical synthesis which depends on comparable advances in other areas of chemistry. Analysis and theories of chemical structure and reactions are determinants in progress in chemical synthesis and are described also. (Author/SA)

  20. Chemistry and Detective Fiction.

    ERIC Educational Resources Information Center

    Labianca, Dominick A.; Reeves, William J.

    1981-01-01

    Describes an interdisciplinary program consisting of two courses. The first course deals with the chemistry of drugs and poisons; the second course focuses on fictional works in which these drugs and poisons are central to the plots. (SK)

  1. Environmental Bioinorganic Chemistry

    ERIC Educational Resources Information Center

    Ochiai, Ei-Ichiro

    1974-01-01

    Discusses some important aspects of bioinorganic chemistry, including interactions of organisms with metallic and nonmetallic elements and compounds. Indicates that many environmental problems are created by human exploitation of nature and technologies if studied from a bioinorganic chemical viewpoint. (CC)

  2. Chemistry for Kids.

    ERIC Educational Resources Information Center

    Sato, Sanae; Majoros, Bela

    1988-01-01

    Reports two methods for interesting children in chemistry. Describes a method for producing large soap bubbles and films for study. Examines the use of simple stories to explain common chemical concepts with example given. Lists titles of available stories. (ML)

  3. Magnetism in Chemistry

    ERIC Educational Resources Information Center

    Brookes, R. W.; McFadyen, W. D.

    1975-01-01

    Discusses the technical aspects of paramagnetism and an electrostatic model called Crystal Field Theory (CFT), very often used in the case of transition metal compounds. Suggests that this discussion be included as an option for college chemistry courses. (MLH)

  4. Chemistry for Nonscientists

    ERIC Educational Resources Information Center

    Weil, Thomas A.; And Others

    1974-01-01

    Discusses the case of DDT which can be introduced to nonscience students in a chemistry course, including the development of DDT, problems associated with its adverse effects, and curtailment of its use in our environments. (CC)

  5. Chemistry with a Peel.

    ERIC Educational Resources Information Center

    Borer, Londa; Larsen, Eric

    1997-01-01

    Presents experiments that introduce natural product chemistry into high school classrooms. In the laboratory activities, students isolate and analyze the oil in orange peels. Students also perform a steam distillation and learn about terpenes. (DDR)

  6. Supplemental instruction in chemistry

    NASA Astrophysics Data System (ADS)

    Lundeberg, Mary A.

    This study was designed to measure some effects of supplemental instruction in chemistry. Supplemental instruction is a peer-led cooperative learning program that encourages students to develop conceptual understanding by articulating both understandings and misconceptions in a think-aloud fashion. Supplemental instruction was offered three hours weekly outside of class and lab time for students in four classes of General Organic and Biological Chemistry. Over a two-year period 108 students volunteered to participate in this program; 45 students did not participate. As measured by final grades in chemistry and responses to a questionnaire, supplemental instruction was effective in increasing students' achievement in chemistry. Further research is needed to determine the in-depth effects of supplemental instruction on students' learning, problem solving, and self-esteem.

  7. Indicators: Soil Chemistry

    EPA Pesticide Factsheets

    The chemical makeup of the soil can provide information on wetland condition, wetland water quality and services being provided by the wetland ecosystem. Analyzing soil chemistry reveals if the soil is contaminated with a toxic chemical or heavy metal.

  8. General Chemistry for Engineers.

    ERIC Educational Resources Information Center

    Kybett, B. D.

    1982-01-01

    Discusses the relationship between molecular structure, intermolecular forces, and tensile strengths of a polymer and suggests that this is a logical way to introduce polymers into a general chemistry course. (Author/JN)

  9. Microfluidics in inorganic chemistry.

    PubMed

    Abou-Hassan, Ali; Sandre, Olivier; Cabuil, Valérie

    2010-08-23

    The application of microfluidics in chemistry has gained significant importance in the recent years. Miniaturized chemistry platforms provide controlled fluid transport, rapid chemical reactions, and cost-saving advantages over conventional reactors. The advantages of microfluidics have been clearly established in the field of analytical and bioanalytical sciences and in the field of organic synthesis. It is less true in the field of inorganic chemistry and materials science; however in inorganic chemistry it has mostly been used for the separation and selective extraction of metal ions. Microfluidics has been used in materials science mainly for the improvement of nanoparticle synthesis, namely metal, metal oxide, and semiconductor nanoparticles. Microfluidic devices can also be used for the formulation of more advanced and sophisticated inorganic materials or hybrids.

  10. Impact of surface chemistry

    PubMed Central

    Somorjai, Gabor A.; Li, Yimin

    2011-01-01

    The applications of molecular surface chemistry in heterogeneous catalyst technology, semiconductor-based technology, medical technology, anticorrosion and lubricant technology, and nanotechnology are highlighted in this perspective. The evolution of surface chemistry at the molecular level is reviewed, and the key roles of surface instrumentation developments for in situ studies of the gas–solid, liquid–solid, and solid–solid interfaces under reaction conditions are emphasized. PMID:20880833

  11. EPA Environmental Chemistry Laboratory

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Environmental Protection Agency's (EPA) Chemistry Laboratory (ECL) is a national program laboratory specializing in residue chemistry analysis under the jurisdiction of the EPA's Office of Pesticide Programs in Washington, D.C. At Stennis Space Center, the laboratory's work supports many federal anti-pollution laws. The laboratory analyzes environmental and human samples to determine the presence and amount of agricultural chemicals and related substances. Pictured, ECL chemists analyze environmental and human samples for the presence of pesticides and other pollutants.

  12. Impact of surface chemistry.

    PubMed

    Somorjai, Gabor A; Li, Yimin

    2011-01-18

    The applications of molecular surface chemistry in heterogeneous catalyst technology, semiconductor-based technology, medical technology, anticorrosion and lubricant technology, and nanotechnology are highlighted in this perspective. The evolution of surface chemistry at the molecular level is reviewed, and the key roles of surface instrumentation developments for in situ studies of the gas-solid, liquid-solid, and solid-solid interfaces under reaction conditions are emphasized.

  13. Technetium Chemistry in HLW

    SciTech Connect

    Hess, Nancy J.; Felmy, Andrew R.; Rosso, Kevin M.; Xia Yuanxian

    2005-06-06

    Tc contamination is found within the DOE complex at those sites whose mission involved extraction of plutonium from irradiated uranium fuel or isotopic enrichment of uranium. At the Hanford Site, chemical separations and extraction processes generated large amounts of high level and transuranic wastes that are currently stored in underground tanks. The waste from these extraction processes is currently stored in underground High Level Waste (HLW) tanks. However, the chemistry of the HLW in any given tank is greatly complicated by repeated efforts to reduce volume and recover isotopes. These processes ultimately resulted in mixing of waste streams from different processes. As a result, the chemistry and the fate of Tc in HLW tanks are not well understood. This lack of understanding has been made evident in the failed efforts to leach Tc from sludge and to remove Tc from supernatants prior to immobilization. Although recent interest in Tc chemistry has shifted from pretreatment chemistry to waste residuals, both needs are served by a fundamental understanding of Tc chemistry.

  14. Reaction chemistry of cerium

    SciTech Connect

    1997-01-01

    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  15. Uranium triamidoamine chemistry.

    PubMed

    Gardner, Benedict M; Liddle, Stephen T

    2015-07-07

    Triamidoamine (Tren) complexes of the p- and d-block elements have been well-studied, and they display a diverse array of chemistry of academic, industrial and biological significance. Such in-depth investigations are not as widespread for Tren complexes of uranium, despite the general drive to better understand the chemical behaviour of uranium by virtue of its fundamental position within the nuclear sector. However, the chemistry of Tren-uranium complexes is characterised by the ability to stabilise otherwise reactive, multiply bonded main group donor atom ligands, construct uranium-metal bonds, promote small molecule activation, and support single molecule magnetism, all of which exploit the steric, electronic, thermodynamic and kinetic features of the Tren ligand system. This Feature Article presents a current account of the chemistry of Tren-uranium complexes.

  16. Collaborative Physical Chemistry Projects Involving Computational Chemistry

    NASA Astrophysics Data System (ADS)

    Whisnant, David M.; Howe, Jerry J.; Lever, Lisa S.

    2000-02-01

    The physical chemistry classes from three colleges have collaborated on two computational chemistry projects using Quantum CAChe 3.0 and Gaussian 94W running on Pentium II PCs. Online communication by email and the World Wide Web was an important part of the collaboration. In the first project, students used molecular modeling to predict benzene derivatives that might be possible hair dyes. They used PM3 and ZINDO calculations to predict the electronic spectra of the molecules and tested the predicted spectra by comparing some with experimental measurements. They also did literature searches for real hair dyes and possible health effects. In the final phase of the project they proposed a synthetic pathway for one compound. In the second project the students were asked to predict which isomer of a small carbon cluster (C3, C4, or C5) was responsible for a series of IR lines observed in the spectrum of a carbon star. After preliminary PM3 calculations, they used ab initio calculations at the HF/6-31G(d) and MP2/6-31G(d) level to model the molecules and predict their vibrational frequencies and rotational constants. A comparison of the predictions with the experimental spectra suggested that the linear isomer of the C5 molecule was responsible for the lines.

  17. JPRS Report, Science & Technology, USSR: Chemistry

    DTIC Science & Technology

    2007-11-02

    This report contains foreign media information from the USSR concerning analytical chemistry, electrochemistry, environmental chemistry, inorganic compounds, organophosphorous compounds, polymers (rubber) and radiation chemistry.

  18. Chemistry in cometary comae

    NASA Technical Reports Server (NTRS)

    Irvine, W. M.; Dickens, J. E.; Lovell, A. J.; Schloerb, F. P.; Senay, M.; Bergin, E. A.; Jewitt, D.; Matthews, H. E.

    1998-01-01

    Significant gas-phase chemistry occurs in the comae of bright comets, as is demonstrated here for the case of Comet Hale-Bopp. The abundance ratio of the two isomers, hydrogen cyanide and hydrogen isocyanide, is shown to vary with heliocentric distance in a way that is consistent with production of HNC by ion-molecule chemistry initiated by the photoionization of water. Likewise, the first maps of emission from HCO+ show an abundance and an extended distribution that are consistent with the same chemical model.

  19. Chemistry of Transactinides

    NASA Astrophysics Data System (ADS)

    Kratz, J. V.

    In this chapter, the chemical properties of the man-made transactinide elements rutherfordium, Rf (element 104), dubnium, Db (element 105), seaborgium, Sg (element 106), bohrium, Bh (element 107), hassium, Hs (element 108), and copernicium, Cn (element 112) are reviewed, and prospects for chemical characterizations of even heavier elements are discussed. The experimental methods to perform rapid chemical separations on the time scale of seconds are presented and comments are given on the special situation with the transactinides where chemistry has to be studied with single atoms. It follows a description of theoretical predictions and selected experimental results on the chemistry of elements 104 through 108, and element 112.

  20. Chemistry WebBook

    National Institute of Standards and Technology Data Gateway

    SRD 69 NIST Chemistry WebBook (Web, free access)   The NIST Chemistry WebBook contains: Thermochemical data for over 7000 organic and small inorganic compounds; thermochemistry data for over 8000 reactions; IR spectra for over 16,000 compounds; mass spectra for over 33,000 compounds; UV/Vis spectra for over 1600 compounds; electronic and vibrational spectra for over 5000 compounds; constants of diatomic molecules(spectroscopic data) for over 600 compounds; ion energetics data for over 16,000 compounds; thermophysical property data for 74 fluids.

  1. Chemistry of atmospheres.

    NASA Astrophysics Data System (ADS)

    Wayne, R. P.

    Atmospheric chemistry has been the focus of much research activity in recent years. Like its predecessor, this new edition lays down the principles of atmospheric chemistry and provides the necessary background for more detailed study. New developments are covered, including the startling discovery of the "Antarctic ozone hole", and the increasingly rapid changes in the composition of the Earth's atmosphere, apparently a result of man's activities. Information gathered by the Voyager 2 and other space missions, which have provided a new understanding of the atmospheres of planets other than our own, is also discussed.

  2. Structure and chemistry of model catalysts in ultrahigh vacuum

    NASA Astrophysics Data System (ADS)

    Walker, Joshua D.

    molecular geometry on electron transport using a range of surface-sensitive techniques. Sulfur-containing molecules, in particular those with sulfur-sulfur linkages, are used as lubricant additives for ferrous surfaces [1-14] so that dialkyl disulfides have been used as simple model compounds to explore the surface and tribological chemistry on iron [15,16] where they react at the high temperatures attained at the interface during rubbing to deposit a ferrous sulfide film. However, the tribological chemistry can depend critically on the nature of the substrate so that a good lubricant additive for one type of surface may not be applicable to another. In particular, the lubrication of sliding copper-copper interfaces in electrical motors [17-20] provides a particular challenge. To study this system surface sensitive techniques Low energy electron diffraction (LEED) and TPD surface analysis was employed. LEED experiments suggest that tribological experiments can be conducted on copper foils rather than copper single crystals and produce comparable results. The ability to produce ideal model catalysts is very important in the Surface science field. To enhance catalytic performance of these catalysts, various strategies can be used in the preparation process. One approach in this quest is to produce an alloy surface that increases the activity of the surface. The process of developing and understanding the chemistry of AuPd alloys was probed in detail using TPD, LEED and Density Functional Theory (DFT).

  3. Organic Chemistry Self Instructional Package 1: Review of General Chemistry.

    ERIC Educational Resources Information Center

    Zdravkovich, V.

    This booklet is one of a series of 17 developed at Prince George's Community College, Largo, Maryland. It provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The…

  4. Connected Chemistry--Incorporating Interactive Simulations into the Chemistry Classroom.

    ERIC Educational Resources Information Center

    Stieff, Mike; Wilensky, Uri

    2003-01-01

    Describes a novel modeling and simulation package and assesses its impact on students' understanding of chemistry. Connected Chemistry was implemented inside the NetLogo modeling environment. Using Connected Chemistry, students employed problem -solving techniques characterized by stronger attempts at conceptual understanding and logical…

  5. Chemistry: Experiments, Demonstrations and Other Activities Suggested for Chemistry.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    This publication is a handbook used in conjunction with the course of study in chemistry developed through the New York State Education Department and The University of the State of New York. It contains experiments, demonstrations, and other activities for a chemistry course. Areas covered include the science of chemistry, the atomic structure of…

  6. Is Chemistry Attractive for Pupils? Czech Pupils' Perception of Chemistry

    ERIC Educational Resources Information Center

    Kubiatko, Milan

    2015-01-01

    Chemistry is an important subject due to understanding the composition and structure of the things around us. The main aim of the study was to find out the perception of chemistry by lower secondary school pupils. The partial aims were to find out the influence of gender, year of study and favorite subject on the perception of chemistry. The…

  7. Turkish Prospective Chemistry Teachers' Beliefs about Chemistry Teaching

    ERIC Educational Resources Information Center

    Boz, Yezdan; Uzuntiryaki, Esen

    2006-01-01

    In order to study the beliefs of Turkish prospective chemistry teachers about teaching chemistry, semi-structured interviews were conducted with 12 prospective teachers. Analysis of the interviews revealed that most of the prospective teachers held intermediate (transition between constructivist and traditional) beliefs about chemistry teaching.…

  8. Emphasizing Mineral Chemistry in an Analytical Chemistry Unit.

    ERIC Educational Resources Information Center

    Dunn, Jeffrey G.; And Others

    1995-01-01

    Describes an analytical chemistry unit in the second year of the chemistry degree course at Curtin University that was designed to reflect the numerous employment opportunities for chemistry graduates in the mineral processing industries and private analytical laboratories. Presents the lecture syllabus, the laboratory course description, and…

  9. Top Down Chemistry Versus Bottom up Chemistry

    NASA Astrophysics Data System (ADS)

    Oka, Takeshi; Witt, Adolf N.

    2016-06-01

    The idea of interstellar top down chemistry (TDC), in which molecules are produced from decomposition of larger molecules and dust in contrast to ordinary bottom up chemistry (BUC) in which molecules are produced synthetically from smaller molecules and atoms in the ISM, has been proposed in the chemistry of PAH and carbon chain molecules both for diffusea,c and dense cloudsb,d. A simple and natural idea, it must have occurred to many people and has been in the air for sometime. The validity of this hypothesis is apparent for diffuse clouds in view of the observed low abundance of small molecules and its rapid decrease with molecular size on the one hand and the high column densities of large carbon molecules demonstrated by the many intense diffuse interstellar bands (DIBs) on the other. Recent identification of C60^+ as the carrier of 5 near infrared DIBs with a high column density of 2×1013 cm-2 by Maier and others confirms the TDC. This means that the large molecules and dust produced in the high density high temperature environment of circumstellar envelopes are sufficiently stable to survive decompositions due to stellar UV radiaiton, cosmic rays, C-shocks etc. for a long time (≥ 10^7 year) of their migration to diffuse clouds and seems to disagree with the consensus in the field of interstellar grains. The stability of molecules and aggregates in the diffuse interstellar medium will be discussed. Duley, W. W. 2006, Faraday Discuss. 133, 415 Zhen,J., Castellanos, P., Paardekooper, D. M., Linnartz, H., Tielens, A. G. G. M. 2014, ApJL, 797, L30 Huang, J., Oka, T. 2015, Mol. Phys. 113, 2159 Guzmán, V. V., Pety, J., Goicoechea, J. R., Gerin, M., Roueff, E., Gratier, P., Öberg, K. I. 2015, ApJL, 800, L33 L. Ziurys has sent us many papers beginning Ziurys, L. M. 2006, PNAS 103, 12274 indicating she had long been a proponent of the idea. Campbell, E. K., Holz, M., Maier, J. P., Gerlich, D., Walker, G. A. H., Bohlender, D, 2016, ApJ, in press Draine, B. T. 2003

  10. USSR Report, Chemistry, No. 98

    DTIC Science & Technology

    2007-11-02

    The report contains information on USSR Chemistry in generally in civil technology with particular attention to biochemistry, Catalysts, Coal ... gasification , combustion, Fertilizers, petroleum processing technology. The report also covers important issues related to polymerization, wood chemistry and Elastomer production.

  11. The Art of Teaching Chemistry.

    ERIC Educational Resources Information Center

    Lloyd, Baird W., Ed.

    1994-01-01

    Contains descriptions of 11 college chemistry education programs that were awarded grants by the Pfizer Foundation because they make the introductory chemistry experience more positive and engaging for students, especially women and minorities. (LZ)

  12. The Lighter Side of Chemistry.

    ERIC Educational Resources Information Center

    Lamb, William G.

    1984-01-01

    Discusses the rationale for using photochemistry to merge descriptive chemistry and molecular orbital theory in first-year chemistry courses. Includes procedures and safety information for various activities, demonstrations, and experiments involving photochemical reactions. (DH)

  13. Polymer Chemistry in High School.

    ERIC Educational Resources Information Center

    Stucki, Roger

    1984-01-01

    Discusses why polymer chemistry should be added to the general chemistry curriculum and what topics are appropriate (listing traditional with related polymer topics). Also discusses when and how these topics should be taught. (JN)

  14. The Mystery of Consumer Chemistry.

    ERIC Educational Resources Information Center

    Anderson, Carol P.

    1988-01-01

    Compares processes used to investigate issues in consumer chemistry to the solving of a puzzle in a mystery story. Suggests using similar methods to teach problem solving in consumer chemistry classes. Describes how such a process might progress. (CW)

  15. The Birthday of Organic Chemistry.

    ERIC Educational Resources Information Center

    Benfey, Otto Theodor; Kaufman, George B.

    1979-01-01

    Describes how the synthesis of urea, 150 years ago, was a major factor in breaking the artificial barrier that existed between organic and inorganic chemistry, and this contributed to the rapid growth of organic chemistry. (GA)

  16. Special Report: Chemistry of Comets.

    ERIC Educational Resources Information Center

    A'Hearn, Michael F.

    1984-01-01

    Discusses the chemistry of comets. How comets provide clues to the birth of the solar system, photolytic reactions on comets involving water, chemical modeling, nuclear chemistry, and research findings are among the areas considered. (JN)

  17. Chemistry in a Nutshell.

    ERIC Educational Resources Information Center

    Rupnow, John; And Others

    1995-01-01

    Presents an activity that involves making peanut butter in the laboratory as a way to teach students the chemistry concepts of emulsification, solubility, and formulation. Enables students to realize that they can actually create or modify the physical and sensory characteristics of peanut butter and taste the differences in their work. (JRH)

  18. Chemistry Between The Stars.

    ERIC Educational Resources Information Center

    Gammon, Richard H.

    This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. The following topics are covered: the physical conditions in interstellar space in comparison with those of the earth, particularly in regard to gas density,…

  19. General Chemistry, 1970 Edition.

    ERIC Educational Resources Information Center

    Dunham, Orson W.; Franke, Douglas C.

    This publication is a syllabus for a senior high school chemistry course designed for the average ability, nonscience major. The content of the syllabus is divided into three basic core areas: Area I: Similarities and Dissimilarities of Matter (9 weeks); Area II: Preparation and Separation of Substances (10 weeks); Area III: Structure and…

  20. The Chemistry of Health.

    ERIC Educational Resources Information Center

    National Inst. of General Medical Sciences (NIH), Bethesda, MD.

    This booklet, geared toward an advanced high school or early college-level audience, describes how basic chemistry and biochemistry research can spur a better understanding of human health. It reveals how networks of chemical reactions keep our bodies running smoothly. Some of the tools and technologies used to explore these reactions are…

  1. Chemistry "en Miniature"

    NASA Astrophysics Data System (ADS)

    Roesky, Herbert W.

    1997-04-01

    By using the video camera projector system we are improving the techniques which are employed in various schools. This is an important reason for employing "Chemistry en Miniature", as this method provides a new means of demonstrating chemical experiments in a lecture hall.

  2. Bringing chemistry to life

    PubMed Central

    Boyce, Michael; Bertozzi, Carolyn R

    2011-01-01

    Bioorthogonal chemistry allows a wide variety of biomolecules to be specifically labeled and probed in living cells and whole organisms. Here we discuss the history of bioorthogonal reactions and some of the most interesting and important advances in the field. PMID:21799498

  3. Chemistry Is Fun.

    ERIC Educational Resources Information Center

    Yaniv, D; And Others

    1982-01-01

    Encouraging scientific thinking through open-ended experiments, allowing students access to common chemical instrumentation, and introduction to laboratory techniques are goals of a high school science laboratory program. Course content (general, inorganic, and organic chemistry), limitations, and course evaluation are discussed. (Author/JN)

  4. Epoxying Isoprene Chemistry

    EPA Science Inventory

    It seems that every few months we read about another missing aspect of atmospheric chemistry: missing products, missing reactivity, missing sources, missing understanding. Thus, it is with some relief that we read in this issue the paper of Paulot et al. The paper provides more...

  5. Green chemistry metrics

    EPA Science Inventory

    Synthetic chemists have always had an objective to achieve reliable and high-yielding routes to the syntheses of targeted molecules. The importance of minimal waste generation has emphasized the use of green chemistry principles and sustainable development. These directions lead ...

  6. Chemistry in the Troposphere.

    ERIC Educational Resources Information Center

    Chameides, William L.; Davis, Douglas D.

    1982-01-01

    Topics addressed in this review of chemistry in the troposphere (layer of atmosphere extending from earth's surface to altitude of 10-16km) include: solar radiation/winds; earth/atmosphere interface; kinetic studies of atmospheric reactions; tropospheric free-radical photochemistry; instruments for nitric oxide detection; sampling…

  7. Chemistry Curricula. Course Suggestions.

    ERIC Educational Resources Information Center

    American Chemical Society, Washington, DC.

    Listings of suggested topics aimed at helping university and college faculties plan courses in the main areas of the chemistry curricula are provided. The suggestions were originally offered as appendices to the American Chemical Society's (ACS) Committee on Professional Training's 1983 guidelines for ACS-approved schools. The course data included…

  8. The Lens of Chemistry

    ERIC Educational Resources Information Center

    Thalos, Mariam

    2013-01-01

    Chemistry possesses a distinctive theoretical lens--a distinctive set of theoretical concerns regarding the dynamics and transformations of a perplexing variety of organic and nonorganic substances--to which it must be faithful. Even if it is true that chemical facts bear a special (reductive) relationship to physical facts, nonetheless it will…

  9. Chemistry by Computer.

    ERIC Educational Resources Information Center

    Garmon, Linda

    1981-01-01

    Describes the features of various computer chemistry programs. Utilization of computer graphics, color, digital imaging, and other innovations are discussed in programs including those which aid in the identification of unknowns, predict whether chemical reactions are feasible, and predict the biological activity of xenobiotic compounds. (CS)

  10. Computational chemistry at Janssen

    NASA Astrophysics Data System (ADS)

    van Vlijmen, Herman; Desjarlais, Renee L.; Mirzadegan, Tara

    2016-12-01

    Computer-aided drug discovery activities at Janssen are carried out by scientists in the Computational Chemistry group of the Discovery Sciences organization. This perspective gives an overview of the organizational and operational structure, the science, internal and external collaborations, and the impact of the group on Drug Discovery at Janssen.

  11. The Chemistry of Health

    ERIC Educational Resources Information Center

    Davis, Alison

    2009-01-01

    Do people realize that chemistry plays a key role in helping solve some of the most serious problems facing the world today? Chemists want to find the building blocks of the chemical universe--the molecules that form materials, living cells and whole organisms. Many chemists are medical explorers looking for new ways to maintain and improve…

  12. Chemistry Cook-Off

    ERIC Educational Resources Information Center

    McCormick, Cynthia

    2012-01-01

    For this activity, high school chemistry students compete in a cooking contest. They must determine the chemical and physical changes that occur in the food they prepare, present their recipe as a step-by-step procedure similar to a lab procedure, identify chemicals in the food, and present all measurements in both metric and English units. The…

  13. Computational chemistry at Janssen.

    PubMed

    van Vlijmen, Herman; Desjarlais, Renee L; Mirzadegan, Tara

    2016-12-19

    Computer-aided drug discovery activities at Janssen are carried out by scientists in the Computational Chemistry group of the Discovery Sciences organization. This perspective gives an overview of the organizational and operational structure, the science, internal and external collaborations, and the impact of the group on Drug Discovery at Janssen.

  14. Using Computers in Chemistry.

    ERIC Educational Resources Information Center

    Pankuch, Brian

    1985-01-01

    Describes the use of two interactive computer programs in a college chemistry course. The first is a commercially-available simulation program (for Apple microcomputers with game paddles) which demonstrates gas laws. The second is a teacher-developed molecular bonding simulation program. (JN)

  15. Chemistry of Meridiani Outcrops

    NASA Technical Reports Server (NTRS)

    Clark, B. C.; Squyres, S. W.; Ming, D. W.; Morris, R. V.; Yen, A.; Gellert, R.; Knoll, A.H.; Arvidson, R. E.

    2006-01-01

    The chemistry and mineralogy of the sulfate-rich sandstone outcrops at Meridiani Planum, Mars, have been inferred from data obtained by the Opportunity rover of the MER mission and reported in recent publications [1-6]. Here, we provide an update on more recent samples and results derived from this extensive data set.

  16. Chemistry and Heritage

    NASA Astrophysics Data System (ADS)

    Vittoria Barbarulo, Maria

    2014-05-01

    Chemistry is the central science, as it touches every aspect of the society we live in and it is intertwined with many aspects of our culture; in particular, the strong link between Chemistry and Archaeology and Art History is being explored, offering a penetrating insight into an area of growing interest from an educational point of view. A series of vital and vibrant examples (i.e., ancient bronzes composition, colour changes due to natural pigment decomposition, marble degradation) has been proposed, on one hand, to improve student understanding of the relationship between cultural and scientific issues arising from the examination, the conservation, and the maintenance of cultural Heritage, on the other, to illustrate the role of the underlying Chemistry. In some case studies, a survey of the most relevant atmospheric factors, which are involved in the deterioration mechanisms, has also been presented to the students. First-hand laboratory experiences have been providing an invaluable means of discovering the full and varied world of Chemistry. Furthermore, the promotion of an interdisciplinary investigation of a famous painting or fresco, involving the study of its nature and significance, the definition of its historical context, any related literature, the chemical knowledge of the materials used, may be an excellent occasion to experiment the Content and Language Integrated Learning (CLIL). The aim of this approach is to convey the important message that everyone has the responsibility to care for and preserve Heritage for the benefit of present and future generations.

  17. The Pimlico Chemistry Trail.

    ERIC Educational Resources Information Center

    Borrows, Peter

    1984-01-01

    Describes a chemistry "trail" (similar to a nature trail) which focuses on chemical phenomena in the environment. The trail includes 20 stops in and around a local school. Types of phenomena examined include building materials, air pollution, corrosion of metals, swimming pools, and others. Additional activities are also suggested. (DH)

  18. Analytical Chemistry Laboratory

    NASA Technical Reports Server (NTRS)

    Anderson, Mark

    2013-01-01

    The Analytical Chemistry and Material Development Group maintains a capability in chemical analysis, materials R&D failure analysis and contamination control. The uniquely qualified staff and facility support the needs of flight projects, science instrument development and various technical tasks, as well as Cal Tech.

  19. Evaluating Environmental Chemistry Textbooks.

    ERIC Educational Resources Information Center

    Hites, Ronald A.

    2001-01-01

    A director of the Indiana University Center for Environmental Science Research reviews textbooks on environmental chemistry. Highlights clear writing, intellectual depth, presence of problem sets covering both the qualitative and quantitative aspects of the material, and full coverage of the topics of concern. Discusses the director's own approach…

  20. General Chemistry Multimedia Problems

    NASA Astrophysics Data System (ADS)

    Whisnant, David M.

    2000-10-01

    Literature Cited

    1. Moore, J. W.; Jacobsen, J. J. Chemistry Comes Alive!, J. Chem. Educ. Software 2000, SP 18 2nd ed., SP 21 2nd ed., SP 23; SP 25; and additional video in press.
    2. Summerlin, L. R.; Borgford, C. F.; Ealy, J. B. Chemical Demonstrations, Volume 2; ACS: Washington, DC, 1987.

  1. Water Chemistry Laboratory Manual.

    ERIC Educational Resources Information Center

    Jenkins, David; And Others

    This manual of laboratory experiments in water chemistry serves a dual function of illustrating fundamental chemical principles of dilute aqueous systems and of providing the student with some familiarity with the chemical measurements commonly used in water and wastewater analysis. Experiments are grouped in categories on the basis of similar…

  2. Getting Reactions to Chemistry.

    ERIC Educational Resources Information Center

    Smith, Walter S.

    1983-01-01

    "COMETS on Careers" describes science-related careers, introduces activities illustrating a science concept being studied, and encourages use of professional persons as activity leaders. Several COMETS chemistry activities are described. These activities, which can be performed in school or at home, focus on colloids, acid/base…

  3. News: Green Chemistry & Technology

    EPA Science Inventory

    A series of 21 articles focused on different features of green chemistry in a recent issue of Chemical Reviews. Topics extended over a wide range to include the design of sustainable synthetic processes to biocatalysis. A selection of perspectives follows as part of this colu

  4. Chemistry: Curriculum Guide.

    ERIC Educational Resources Information Center

    Harlandale Independent School District, San Antonio, TX. Career Education Center.

    The guide is arranged in vertical columns relating the chemistry curriculum concepts to curriculum performance objectives, career concepts and career performance objectives, suggested teaching methods, and resource materials. Occupational information for 40 different occupations includes job duties, educational requirements, salary range, and…

  5. Microscale Gas Chemistry

    ERIC Educational Resources Information Center

    Mattson, Bruce; Anderson, Michael P.

    2011-01-01

    The development of syringes having free movement while remaining gas-tight enabled methods in chemistry to be changed. Successfully containing and measuring volumes of gas without the need to trap them using liquids made it possible to work with smaller quantities. The invention of the LuerLok syringe cap also allowed the gas to be stored for a…

  6. USSR Report, Chemistry

    DTIC Science & Technology

    2007-11-02

    obtained from copyright owner» JPRS-UCH-85-009 24 July 19 85 USSR REPORT CHEMISTRY CONTENTS ADSORPTION Adsorption Thermoluminescence of Oxides of...541.183 ADSORPTION THERMOLUMINESCENCE OF OXIDES OF MAGNESIUM AND CALCIUM IN OXYGEN Moscow KHIMICHESKAYA FIZIKA in Russian Vol 4, No 3, Mar 85

  7. Greener and Sustainable Chemistry

    EPA Science Inventory

    The special issue on Greener and Sustainable Chemistry highlights various strategies that can be adopted to address the pollution preventive measures promoting the use of energy efficient reactions that utilize benign and bio-renewable raw materials in a relatively safer reaction...

  8. Chemistry between the stars

    NASA Technical Reports Server (NTRS)

    Gammon, R. H.

    1976-01-01

    A unit is presented for the secondary school teacher of physics, chemistry, astronomy, or earth sciences. Included are a list of reference materials, teaching aids, and projects. Discussion questions and a glossary are also provided. Concepts developed are: the nature of interstellar space, spectroscopy, molecular signals from space and interstellar molecules and other areas of astronomy.

  9. Get Cooking with Chemistry!

    ERIC Educational Resources Information Center

    American Chemical Society, Washington, DC.

    This book presents science activities investigating the chemical changes and reactions with powders that are used in baking. Activities include: (1) Mystery Powders; (2) Find the Fizz: Discover the Secret of Baking Powder; and (3) A Feast for Yeast and Cheese: Behold the Power of Chemistry. (YDS)

  10. The Language of Chemistry.

    ERIC Educational Resources Information Center

    Bretz, Stacey Lowery; Meinwald, Jerrold

    2002-01-01

    Describes a new curriculum called The Language of Chemistry designed to illustrate how problems of biological and/or medical importance can be understood on a molecular basis and to show that the logic, knowledge, and language needed are easily accessible. Among the case studies in the curriculum are the giant peacock moth, bacterial chemotaxis,…

  11. Online Organic Chemistry

    ERIC Educational Resources Information Center

    Janowicz, Philip A.

    2010-01-01

    This is a comprehensive study of the many facets of an entirely online organic chemistry course. Online homework with structure-drawing capabilities was found to be more effective than written homework. Online lecture was found to be just as effective as in-person lecture, and students prefer an online lecture format with shorter Webcasts. Online…

  12. Polyhedra in (inorganic) chemistry.

    PubMed

    Alvarez, Santiago

    2005-07-07

    A systematic description of polyhedra with varying degrees of regularity is illustrated with examples of chemical structures, mostly from different fields of Inorganic Chemistry. Also the geometrical relationships between different polyhedra are highlighted and their application to the analysis of complex structures is discussed.

  13. An Advanced Chemistry Laboratory Program.

    ERIC Educational Resources Information Center

    Wise, John H.

    The Advanced Chemistry Laboratory Program is a project designed to devise experiments to coordinate the use of instruments in the laboratory programs of physical chemistry, instrumental analysis, and inorganic chemistry at the advanced undergraduate level. It is intended that such experiments would incorporate an introduction to the instrument…

  14. Six Pillars of Organic Chemistry

    ERIC Educational Resources Information Center

    Mullins, Joseph J.

    2008-01-01

    This article describes an approach to teaching organic chemistry, which is to have students build their knowledge of organic chemistry upon a strong foundation of the fundamental concepts of the subject. Specifically, the article focuses upon a core set of concepts that I call "the six pillars of organic chemistry": electronegativity, polar…

  15. Chemistry 200, 300 Interim Guide.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education, Winnipeg.

    This guide, developed for the chemistry 200, 300 program in Manitoba, is designed to articulate with previous science courses, provide concepts, processes, and skills which will enable students to continue in chemistry-related areas, and relate chemistry to practical applications in everyday life. It includes a program overview (with program goals…

  16. Towards "Bildung"-Oriented Chemistry Education

    ERIC Educational Resources Information Center

    Sjöström, Jesper

    2013-01-01

    This paper concerns "Bildung"-oriented chemistry education, based on a reflective and critical discourse of chemistry. It is contrasted with the dominant type of chemistry education, based on the mainstream discourse of chemistry. "Bildung"-oriented chemistry education includes not only content knowledge in chemistry, but also…

  17. Aqueous chemistry of iodine

    SciTech Connect

    Toth, L.M.; Pannell, K.D.; Kirkland, O.L.

    1984-01-01

    The chemistry of iodine has been examined in aqueous solutions of pH 6 to 10 containing 2500 ppM boron as H/sub 3/BO/sub 3/ at temperatures up to 150/sup 0/C using absorption spectrophotometry to identify and monitor the iodine species present. Kinetic rate constants for the disproportionation of the HOI intermediate, 3HOI= IO/sub 3//sup -/ + 2I/sup -/ + 3H/sup +/, have been measured as a function of pH even though no direct spectral evidence for HOI itself has been observed. An HOI partition coefficient >10/sup 4/ has been estimated; results of ionic strength tests are consistent with HOI being present as an uncharged triatomic species in solution. Redox and radiation effects on the aqueous iodine chemistry have also been described. 11 refs., 2 figs., 3 tabs.

  18. Quo vadis, analytical chemistry?

    PubMed

    Valcárcel, Miguel

    2016-01-01

    This paper presents an open, personal, fresh approach to the future of Analytical Chemistry in the context of the deep changes Science and Technology are anticipated to experience. Its main aim is to challenge young analytical chemists because the future of our scientific discipline is in their hands. A description of not completely accurate overall conceptions of our discipline, both past and present, to be avoided is followed by a flexible, integral definition of Analytical Chemistry and its cornerstones (viz., aims and objectives, quality trade-offs, the third basic analytical reference, the information hierarchy, social responsibility, independent research, transfer of knowledge and technology, interfaces to other scientific-technical disciplines, and well-oriented education). Obsolete paradigms, and more accurate general and specific that can be expected to provide the framework for our discipline in the coming years are described. Finally, the three possible responses of analytical chemists to the proposed changes in our discipline are discussed.

  19. Medicinal chemistry for 2020

    PubMed Central

    Satyanarayanajois, Seetharama D; Hill, Ronald A

    2011-01-01

    Rapid advances in our collective understanding of biomolecular structure and, in concert, of biochemical systems, coupled with developments in computational methods, have massively impacted the field of medicinal chemistry over the past two decades, with even greater changes appearing on the horizon. In this perspective, we endeavor to profile some of the most prominent determinants of change and speculate as to further evolution that may consequently occur during the next decade. The five main angles to be addressed are: protein–protein interactions; peptides and peptidomimetics; molecular diversity and pharmacological space; molecular pharmacodynamics (significance, potential and challenges); and early-stage clinical efficacy and safety. We then consider, in light of these, the future of medicinal chemistry and the educational preparation that will be required for future medicinal chemists. PMID:22004084

  20. Evolution of hydroformylation chemistry

    SciTech Connect

    Slaugh, L.H.

    1995-12-01

    A new generation of hydroformylation catalysts was discovered in 1960 at Shell Development Company which dramatically altered the chemistry of producing industrially important alcohols from synthesis gas (CO/H{sub 2}) and olefins. These new homogeneous catalysts were obtained via the use of auxiliary tertiary phosphine ligands with the conventional OXO cobalt carbonyl catalyst. This is believed to have been the first historical example illustrating the utility of phosphine ligands to modify the catalytic properties of homogenous catalysts. In contradistinction to the conventional OXO reaction, highly linear alcohols were obtained in a single-step operation with ease of catalyst recycle. Based on this discovery, an industrial process was developed to produce large volume, environmentally friendly detergent alcohols. The chemistry of this process and a comparison with other hydroformylation catalyst systems will be made. Recent results obtained with phosphine-modified cobalt catalysts for the hydroformylation of substrates other than olefins will be presented.

  1. Chemistry of silybin.

    PubMed

    Biedermann, D; Vavříková, E; Cvak, L; Křen, V

    2014-09-01

    Silybin, a secondary metabolite isolated from the seeds of the blessed milk thistle (Silybum marianum) was discovered as the first member of a new family of natural compounds called flavonolignans in 1959. Over the years it has received the research attention of many organic chemists. This research has resulted in a number of semisynthetic derivatives prepared in an effort to modulate and better target the biological activities of silybin or to improve its physical properties, such as its solubility. A fundamental breakthrough in silybin chemistry was the determination of the absolute configurations of silybin A and silybin B, and the development of methods for their separation. This review covers articles dealing with silybin chemistry and also summarizes all the derivatives prepared.

  2. Turbine Chemistry Modeling

    NASA Technical Reports Server (NTRS)

    Liu, Nan-Suey; Wey, Thomas

    2001-01-01

    Many of the engine exhaust species resulting in significant environmental impact exist in trace amounts. Recent research, e.g., conducted at MIT-AM, has pointed to the intra-engine environment as a possible site for important trace chemistry activity. In addition, the key processes affecting the trace species activity occurring downstream in the air passages of the turbine and exhaust nozzle are not well understood. Most recently, an effort has been initiated at NASA Glenn Research Center under the UEET Program to evaluate and further develop CFD-based technology for modeling and simulation of intra-engine trace chemical changes relevant to atmospheric effects of pollutant emissions from aircraft engines. This presentation will describe the current effort conducted at Glenn; some preliminary results relevant to the trace species chemistry in a turbine passage will also be presented to indicate the progress to date.

  3. Heterogeneous atmospheric chemistry

    NASA Technical Reports Server (NTRS)

    Schryer, D. R.

    1982-01-01

    The present conference on heterogeneous atmospheric chemistry considers such topics concerning clusters, particles and microparticles as common problems in nucleation and growth, chemical kinetics, and catalysis, chemical reactions with aerosols, electron beam studies of natural and anthropogenic microparticles, and structural studies employing molecular beam techniques, as well as such gas-solid interaction topics as photoassisted reactions, catalyzed photolysis, and heterogeneous catalysis. Also discussed are sulfur dioxide absorption, oxidation, and oxidation inhibition in falling drops, sulfur dioxide/water equilibria, the evidence for heterogeneous catalysis in the atmosphere, the importance of heterogeneous processes to tropospheric chemistry, soot-catalyzed atmospheric reactions, and the concentrations and mechanisms of formation of sulfate in the atmospheric boundary layer.

  4. [Gaubius and medical chemistry].

    PubMed

    van Gijn, Jan; Gijselhart, Joost P

    2011-01-01

    Hieronymus David Gaub (1705-1780) was the son of a protestant cloth merchant in Heidelberg. Disliking a pietistic boarding school in Halle, Germany, he came to stay with a paternal uncle who was a physician in Amsterdam. Hieronymus studied medicine in Harderwijk and in Leiden, under the guidance of Herman Boerhaave (1668-1738). In 1731 he was appointed reader (and in 1734 professor) in chemistry at the Leiden medical faculty. After Boerhaave's death he also taught medicine, but without access to hospital beds. Gaubius correctly envisaged that chemistry would become an important discipline in medicine, but was limited by the technical constraints of his time. In his textbook of general pathology (1758) he attributed disease to disturbances of not only fluids, but also solid parts, although symptoms remained the basis of his classification. The book would remain influential for several decades, until the advent of pathological anatomy.

  5. Nuclear analytical chemistry

    SciTech Connect

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

    1984-01-01

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

  6. Carbohydrates in Supramolecular Chemistry.

    PubMed

    Delbianco, Martina; Bharate, Priya; Varela-Aramburu, Silvia; Seeberger, Peter H

    2016-02-24

    Carbohydrates are involved in a variety of biological processes. The ability of sugars to form a large number of hydrogen bonds has made them important components for supramolecular chemistry. We discuss recent advances in the use of carbohydrates in supramolecular chemistry and reveal that carbohydrates are useful building blocks for the stabilization of complex architectures. Systems are presented according to the scaffold that supports the glyco-conjugate: organic macrocycles, dendrimers, nanomaterials, and polymers are considered. Glyco-conjugates can form host-guest complexes, and can self-assemble by using carbohydrate-carbohydrate interactions and other weak interactions such as π-π interactions. Finally, complex supramolecular architectures based on carbohydrate-protein interactions are discussed.

  7. Chemistry of superheavy elements.

    PubMed

    Schädel, Matthias

    2006-01-09

    The number of chemical elements has increased considerably in the last few decades. Most excitingly, these heaviest, man-made elements at the far-end of the Periodic Table are located in the area of the long-awaited superheavy elements. While physical techniques currently play a leading role in these discoveries, the chemistry of superheavy elements is now beginning to be developed. Advanced and very sensitive techniques allow the chemical properties of these elusive elements to be probed. Often, less than ten short-lived atoms, chemically separated one-atom-at-a-time, provide crucial information on basic chemical properties. These results place the architecture of the far-end of the Periodic Table on the test bench and probe the increasingly strong relativistic effects that influence the chemical properties there. This review is focused mainly on the experimental work on superheavy element chemistry. It contains a short contribution on relativistic theory, and some important historical and nuclear aspects.

  8. Organic Chemistry in Space

    NASA Technical Reports Server (NTRS)

    Charnley, Steven

    2009-01-01

    Astronomical observations, theoretical modeling, laboratory simulation and analysis of extraterrestrial material have enhanced our knowledge of the inventory of organic matter in the interstellar medium (ISM) and on small bodies such as comets and asteroids (Ehrenfreund & Charnley 2000). Comets, asteroids and their fragments, meteorites and interplanetary dust particles (IDPs), contributed significant amounts of extraterrestrial organic matter to the young Earth. This material degraded and reacted in a terrestrial prebiotic chemistry to form organic structures that may have served as building blocks for life on the early Earth. In this talk I will summarize our current understanding of the organic composition and chemistry of interstellar clouds. Molecules of astrobiological relevance include the building blocks of our genetic material: nucleic acids, composed of subunits such as N-heterocycles (purines and pyrimidines), sugars and amino acids. Signatures indicative of inheritance of pristine and modified interstellar material in comets and meteorites will also be discussed.

  9. Wet chemistry instrument prototype

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A wet chemistry instrument prototype for detecting amino acids in planetary soil samples was developed. The importance of amino acids and their condensation products to the development of life forms is explained. The characteristics of the instrument and the tests which were conducted to determine the materials compatibility are described. Diagrams are provided to show the construction of the instrument. Data obtained from the performance tests are reported.

  10. Analytical Chemistry in Russia.

    PubMed

    Zolotov, Yuri

    2016-09-06

    Research in Russian analytical chemistry (AC) is carried out on a significant scale, and the analytical service solves practical tasks of geological survey, environmental protection, medicine, industry, agriculture, etc. The education system trains highly skilled professionals in AC. The development and especially manufacturing of analytical instruments should be improved; in spite of this, there are several good domestic instruments and other satisfy some requirements. Russian AC has rather good historical roots.

  11. USSR Report, Chemistry

    DTIC Science & Technology

    1987-03-17

    EKSPERIMENTALNAYA KHIMIYA, No 4, Jul-Aug 86) 5 Synthesis and Catalytic Properties of Cesite (0. A. Mulina, N. F. Meged, et al.; ZHURNAL FIZICHESKOY...Plenum of Central Committee of Chemical and Petrochemical Workers’ Trade Union (Yu. I. Vlasov; KAUCHUK I REZINA; No 10, Oct 86) 27 Synthesis and...al.; ZHURNAL NEORGANICHESKOY KHIMII, No 9, Sep 86) 34 Synthesis and Physical Chemistry Study of LiCrTeO^ (0. V. Sorokina, I. G. Chaban, et al

  12. Green chemistry: development trajectory

    NASA Astrophysics Data System (ADS)

    Moiseev, I. I.

    2013-07-01

    Examples of applications of green chemistry methods in heavy organic synthesis are analyzed. Compounds, which can be produced by the processing of the biomass, and the criteria for the selection of the most promising products are summarized. The current status of the ethanol production and processing is considered. The possibilities of the use of high fatty acid triglycerides, glycerol, succinic acid, and isoprene are briefly discussed. The bibliography includes 67 references.

  13. General chemistry students' understanding of the chemistry underlying climate science

    NASA Astrophysics Data System (ADS)

    Versprille, Ashley N.

    The purpose of this study is to investigate first-semester general chemistry students' understanding of the chemistry underlying climate change. The first part of this study involves the collection of qualitative data from twenty-four first-semester general chemistry students from a large Midwestern research institution. The semi-structured interview protocol was developed based on alternative conceptions identified in the research literature and the essential principles of climate change outlined in the U.S. Climate Change Science Program (CCSP) document which pertain to chemistry (CCSP, 2003). The analysis and findings from the interviews indicate conceptual difficulties for students, both with basic climate literacy and underlying chemistry concepts. Students seem to confuse the greenhouse effect, global warming, and the ozone layer, and in terms of chemistry concepts, they lack a particulate level understanding of greenhouse gases and their interaction with electromagnetic radiation, causing them to not fully conceptualize the greenhouse effect and climate change. Based on the findings from these interviews, a Chemistry of Climate Science Diagnostic Instrument (CCSI) was developed for use in courses that teach chemistry with a rich context such as climate science. The CCSI is designed for professors who want to teach general chemistry, while also addressing core climate literacy principles. It will help professors examine their students' prior knowledge and alternative conceptions of the chemistry concepts associated with climate science, which could then inform their teaching and instruction.

  14. Advanced Chemistry Basins Model

    SciTech Connect

    William Goddard; Mario Blanco; Lawrence Cathles; Paul Manhardt; Peter Meulbroek; Yongchun Tang

    2002-11-10

    The DOE-funded Advanced Chemistry Basin model project is intended to develop a public domain, user-friendly basin modeling software under PC or low end workstation environment that predicts hydrocarbon generation, expulsion, migration and chemistry. The main features of the software are that it will: (1) afford users the most flexible way to choose or enter kinetic parameters for different maturity indicators; (2) afford users the most flexible way to choose or enter compositional kinetic parameters to predict hydrocarbon composition (e.g., gas/oil ratio (GOR), wax content, API gravity, etc.) at different kerogen maturities; (3) calculate the chemistry, fluxes and physical properties of all hydrocarbon phases (gas, liquid and solid) along the primary and secondary migration pathways of the basin and predict the location and intensity of phase fractionation, mixing, gas washing, etc.; and (4) predict the location and intensity of de-asphaltene processes. The project has be operative for 36 months, and is on schedule for a successful completion at the end of FY 2003.

  15. Covalent Chemistry beyond Molecules.

    PubMed

    Jiang, Juncong; Zhao, Yingbo; Yaghi, Omar M

    2016-03-16

    Linking molecular building units by covalent bonds to make crystalline extended structures has given rise to metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), thus bringing the precision and versatility of covalent chemistry beyond discrete molecules to extended structures. The key advance in this regard has been the development of strategies to overcome the "crystallization problem", which is usually encountered when attempting to link molecular building units into covalent solids. Currently, numerous MOFs and COFs are made as crystalline materials in which the large size of the constituent units provides for open frameworks. The molecular units thus reticulated become part of a new environment where they have (a) lower degrees of freedom because they are fixed into position within the framework; (b) well-defined spatial arrangements where their properties are influenced by the intricacies of the pores; and (c) ordered patterns onto which functional groups can be covalently attached to produce chemical complexity. The notion of covalent chemistry beyond molecules is further strengthened by the fact that covalent reactions can be carried out on such frameworks, with full retention of their crystallinity and porosity. MOFs are exemplars of how this chemistry has led to porosity with designed metrics and functionality, chemically-rich sequences of information within their frameworks, and well-defined mesoscopic constructs in which nanoMOFs enclose inorganic nanocrystals and give them new levels of spatial definition, stability, and functionality.

  16. Chemistry of sex attraction.

    PubMed Central

    Roelofs, W L

    1995-01-01

    The chemical communication system used to attract mates involves not only the overt chemical signals but also indirectly a great deal of chemistry in the emitter and receiver. As an example, in emitting female moths, this includes enzymes (and cofactors, mRNA, genes) of the pheromone biosynthetic pathways, hormones (and genes) involved in controlling pheromone production, receptors and second messengers for the hormones, and host plant cues that control release of the hormone. In receiving male moths, this includes the chemistry of pheromone transportation in antennal olfactory hairs (binding proteins and sensillar esterases) and the chemistry of signal transduction, which includes specific dendritic pheromone receptors and a rapid inositol triphosphate second messenger signal. A fluctuating plume structure is an integral part of the signal since the antennal receptors need intermittent stimulation to sustain upwind flight. Input from the hundreds of thousands of sensory cells is processed and integrated with other modalities in the central nervous system, but many unknown factors modulate the information before it is fed to motor neurons for behavioral responses. An unknown brain control center for pheromone perception is discussed relative to data from behavioral-threshold studies showing modulation by biogenic amines, such as octopamine and serotonin, from genetic studies on pheromone discrimination, and from behavioral and electrophysiological studies with behavioral antagonists. Images Fig. 1 PMID:7816846

  17. Chemistry and cosmology.

    PubMed

    Black, John H

    2006-01-01

    The simplest elements, hydrogen and helium, offer a remarkably rich chemistry, which has controlled crucial features of the early evolution of the universe. Theoretical models of the origin of structure (stars, galaxies, clusters of galaxies, etc.) now incorporate this chemistry in some detail. In addition to the origin of structure, cosmologists are concerned with observational tests of competing world models. Primordial chemistry may give rise to some of the earliest departures from thermodynamic equilibrium in the universe. These effects may be observable as broad-band spectroscopic distortions of the cosmic background radiation, which otherwise exhibits a nearly perfect blackbody spectrum. The chemical history of the expanding universe is followed through a detailed calculation of the evolution of the abundances of H, H+, H-, H2, H2+, H3+, and other minor species. It is shown that continuous absorption by the small concentration of H- can produce a distortion in the cosmic background spectrum with a maximum at a frequency near nu/c = 9 cm-1 (wavelength 1.1 mm). The predicted effect lies only a factor of 5 below current limits. Its detection would provide an important test of our understanding of the recombination epoch of the universe.

  18. Assessment of long-term subacute exposure to dimethoate by hair analysis of dialkyl phosphates DMP and DMTP in exposed rabbits: The effects of dose, dose duration and hair colour.

    PubMed

    Margariti, Maria G; Tsatsakis, Aristidis M

    2009-10-01

    Hair analysis for dialkyl phosphates' (DAPs) residues could provide a measure of chronic exposure to organophosphate pesticides (OPs). The aim of this study was to determine whether these metabolites can be internally incorporated into the hair of rabbits exposed to dimethoate and also to investigate the influence of dose and dose duration of this OP, as well as the effect of hair colour on the concentrations of its DAPs in hair. Two-coloured rabbits were daily exposed to dimethoate (0, 12 or 24mgkg(-1) body weight) via their drinking water. Hair samples of both colours were obtained 4 and 6 months after the beginning of exposure from the back of all treated rabbits, and each hair colour sample was analyzed for dimethyl phosphate (DMP) and dimethyl thiophosphate (DMTP) by gas chromatography-mass spectrometry (GC-MS). Analysis revealed the incorporation of these metabolites into the rabbit hair in a dose-dependent manner. The mean concentrations found ranged from 0.18 to 0.77ngmg(-1) for DMP and from 0.43 to 1.53ngmg(-1) for DMTP. Mixed results for the significance of the relationship between dose duration and the levels of the two DAPs in hair are observed. Hair pigmentation does not appear to affect the concentration values of DMTP, whereas it seems to be a critical factor in the incorporation of DMP into hair. These data confirm the ability of hair testing to assess chronic OP exposure by the detection of DAPs.

  19. A new class of organosuperbases, N-alkyl- and N-aryl-1,3-dialkyl-4,5-dimethylimidazol-2-ylidene amines: synthesis, structure, pK(BH+) measurements, and properties.

    PubMed

    Kunetskiy, Roman A; Polyakova, Svetlana M; Vavřík, Jiří; Císařová, Ivana; Saame, Jaan; Nerut, Eva Roos; Koppel, Ivar; Koppel, Ilmar A; Kütt, Agnes; Leito, Ivo; Lyapkalo, Ilya M

    2012-03-19

    A series of stable organosuperbases, N-alkyl- and N-aryl-1,3-dialkyl-4,5-dimethylimidazol-2-ylidene amines, were efficiently synthesized from N,N'-dialkylthioureas and 3-hydroxy-2-butanone and their basicities were measured in acetonitrile. The derivatives with tert-alkyl groups on the imino nitrogen were found to be more basic than the tBuP(1) (pyrr) phosphazene base in acetonitrile. The origin of the high basicity of these compounds is discussed. In acetonitrile and in the gas phase, the basicity of the alkylimino derivatives depends on the size of the substituent at the imino group, which influences the degree of aromatization of the imidazole ring, as measured by (13)C NMR chemical shifts or by the calculated ΔNICS(1) aromaticity parameters, as well as on solvation effects. If a wider range of imino-substituents, including electron-acceptor substituents, is treated in the analysis then the influence of aromatization is less predominant and the gas-phase basicity becomes more dependent on the field-inductive effect, polarizability, and resonance effects of the substituent.

  20. Syntheses and properties of a series of novel surface active salts based on 1,4-dialkyl-1,4-diazoniabicyclo[2.2.2]octane and their supermolecular interactions with cucurbit[6]uril

    NASA Astrophysics Data System (ADS)

    Xu, Fei; Chen, Hongyu; Zhang, Haibo; Cheng, Gongzhen; Zhou, Xiaohai

    2012-06-01

    A series of novel surface active salts, 1,4-dialkyl-1,4-diazoniabicyclo[2.2.2]octane bromides (2CxDABCOBr2), have been synthesized and characterized. Their melting points show a U-shaped curve with increasing alkyl chain length, while the decomposition temperatures do not show significant differences. Critical aggregation concentration (cac) of 2C6DABCOBr2 determined by the concentration dependence of 1H NMR chemical shifts is about 100 mmol L-1, which is in good agreement with the cac obtained by electrical conductivity and surface tension measurement. The aggregation number of 2C6DABCOBr2 in aqueous solutions studied with a detailed analysis of 1H NMR is 36. The interaction between 2C6DABCOBr2 and cucurbit[6]uril in aqueous solution has also been investigated by 1H NMR and spin-lattice relaxation time measurement (T1), indicating the formation of a complex with one alkyl chain of 2C6DABCOBr2 inserted into the cavity of CB[6].

  1. Spotlight on medicinal chemistry education.

    PubMed

    Pitman, Simone; Xu, Yao-Zhong; Taylor, Peter; Turner, Nicholas; Coaker, Hannah; Crews, Kasumi

    2014-05-01

    The field of medicinal chemistry is constantly evolving and it is important for medicinal chemists to develop the skills and knowledge required to succeed and contribute to the advancement of the field. Future Medicinal Chemistry spoke with Simone Pitman (SP), Yao-Zhong Xu (YX), Peter Taylor (PT) and Nick Turner (NT) from The Open University (OU), which offers an MSc in Medicinal Chemistry. In the interview, they discuss the MSc course content, online teaching, the future of medicinal chemistry education and The OU's work towards promoting widening participation. SP is a Qualifications Manager in the Science Faculty at The OU. She joined The OU in 1993 and since 1998 has been involved in the Postgraduate Medicinal Chemistry provision at The OU. YX is a Senior Lecturer in Bioorganic Chemistry at The OU. He has been with The OU from 2001, teaching undergraduate courses of all years and chairing the master's course on medicinal chemistry. PT is a Professor of Organic Chemistry at The OU and has been involved with the production and presentation of The OU courses in Science and across the university for over 30 years, including medicinal chemistry modules at postgraduate level. NT is a Lecturer in Analytical Science at The OU since 2009 and has been involved in the production of analytical sciences courses, as well as contributing to the presentation of a number of science courses including medicinal chemistry.

  2. More Chemistry with Light! More Light in Chemistry!

    PubMed

    Bach, Thorsten

    2015-09-21

    "…︁ Why is chemistry overlooked when talking about light? Is the photon a physical particle per se? Are all important light-induced processes biological? Maybe the role of light for chemistry and the role of chemistry for light may be far less important than a few eccentric scientists would like to believe. From the perspective of a synthetically oriented photochemist, however, the facts are different …︁" Read more in the Editorial by Thorsten Bach.

  3. The role of transition metal ions chemistry on multiphase chemistry

    NASA Astrophysics Data System (ADS)

    Deguillaume, L.; Leriche, M.; Monod, A.; Chaumerliac, N.

    2003-04-01

    A modelling study of the role of transition metal ions chemistry on cloud chemistry is presented. First, new developments of the Model of Multiphase Cloud Chemistry (M2C2) are described: the transition metal ions reactivity and variable photolysis in the aqueous phase. Secondly, three summertime scenarios describing urban, remote and marine conditions are simulated. First, comparisons between results from M2C2 and from CAPRAM2.3 models for the same scenarios (Herrmann et al., 2000) show a good agreement between the two models with respect to their different chemical mechanisms. Secondly, chemical regimes in cloud are analysed to understand the role of transition metal ions chemistry on cloud chemistry. This study focuses on HOx chemistry, which afterwards influences the sulphur and the VOCs chemistry in droplets. The ratio of Fe(II)/Fe(III) exhibits a diurnal variation with values in agreement with the few measurements of Fe speciation available. In the polluted case, sensitivity tests with and without TMI chemistry, show an enhancement of OH concentration in the aqueous phase when TMI chemistry is considered. This implies a more important oxidation of VOCs in droplets, which produces the HO2 radical, the hydrogen peroxide precursor. In fact, the HO2 radical is mainly converted into hydrogen peroxide by reactions between HO2/O2- radicals with Fe(II). This production of hydrogen peroxide leads to a rapid conversion of S(IV) into S(VI) at the beginning of the simulation.

  4. Tropospheric Halogen Chemistry

    NASA Astrophysics Data System (ADS)

    von Glasow, R.; Crutzen, P. J.

    2003-12-01

    Halogens are very reactive chemicals that are known to play an important role in anthropogenic stratospheric ozone depletion chemistry, first recognized by Molina and Rowland (1974). However, they also affect the chemistry of the troposphere. They are of special interest because they are involved in many reaction cycles that can affect the oxidation power of the atmosphere indirectly by influencing the main oxidants O3 and its photolysis product OH and directly, e.g., by reactions of the Cl radical with hydrocarbons (e.g., CH4).Already by the middle of the nineteenth century, Marchand (1852) reported the presence of bromine and iodine in rain and other natural waters. He also mentions the benefits of iodine in drinking water through the prevention of goitres and cretinism. In a prophetic monograph "Air and Rain: The Beginnings of a Chemical Climatology," Smith (1872) describes measurements of chloride in rain water, which he states to originate partly from the oceans by a process that he compares with the bursting of "soap bubbles" which produces "small vehicles" that transfer small spray droplets of seawater to the air. From deviations of the sulfate-to-chloride ratio in coastal rain compared to seawater, Smith concluded that chemical processes occur once the particles are airborne.For almost a century thereafter, however, atmospheric halogens received little attention. One exception was the work by Cauer (1939), who reported that iodine pollution has been significant in Western and Central Europe due to the inefficient burning of seaweed, causing mean gas phase atmospheric concentrations as high as or greater than 0.5 μg m-3. In his classical textbook Air Chemistry and Radioactivity, Junge (1963) devoted less than three pages to halogen gas phase chemistry, discussing chlorine and iodine. As reviewed by Eriksson (1959a, b), the main atmospheric source of halogens is sea salt, derived from the bursting of bubbles of air which are produced by ocean waves and other

  5. Green Chemistry: Progress and Barriers

    NASA Astrophysics Data System (ADS)

    Green, Sarah A.

    2016-10-01

    Green chemistry can advance both the health of the environment and the primary objectives of the chemical enterprise: to understand the behavior of chemical substances and to use that knowledge to make useful substances. We expect chemical research and manufacturing to be done in a manner that preserves the health and safety of workers; green chemistry extends that expectation to encompass the health and safety of the planet. While green chemistry may currently be treated as an independent branch of research, it should, like safety, eventually become integral to all chemistry activities. While enormous progress has been made in shifting from "brown" to green chemistry, much more effort is needed to effect a sustainable economy. Implementation of new, greener paradigms in chemistry is slow because of lack of knowledge, ends-justify-the-means thinking, systems inertia, and lack of financial or policy incentives.

  6. Mars aqueous chemistry experiment

    NASA Technical Reports Server (NTRS)

    Clark, Benton C.; Mason, Larry W.

    1993-01-01

    The Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. Progress for the first year MACE PIDDP is reported in two major areas of effort: (1) fluids handling concepts, definition, and breadboard fabrication and (2) aqueous chemistry ion sensing technology and test facility integration. A fluids handling breadboard was designed, fabricated, and tested at Mars ambient pressure. The breadboard allows fluid manipulation scenarios to be tested under the reduced pressure conditions expected in the Martian atmosphere in order to validate valve operations, orchestrate analysis sequences, investigate sealing integrity, and to demonstrate efficacy of the fluid handling concept. Additional fluid manipulation concepts have also been developed based on updated MESUR spacecraft definition. The Mars Aqueous Chemistry Experiment Ion Selective Electrode (ISE) facility was designed as a test bed to develop a multifunction interface for measurements of chemical ion concentrations in aqueous solution. The interface allows acquisition of real time data concerning the kinetics and heats of salt dissolution, and transient response to calibration and solubility events. An array of ion selective electrodes has been interfaced and preliminary calibration studies performed.

  7. Chemistry and Science Fiction

    NASA Astrophysics Data System (ADS)

    Stocker, Jack H.

    1998-11-01

    This lively collection looks at science as filtered through literature, film, and television. It discusses classic works in science fiction and provides an in-depth look at the chemistry depicted in popular culture, particularly in Start Trek , Star Wars , and Doctor Who . It includes an examination by Nebula Award winner Connie Willis of how science fiction authors use science, and reprints two tongue-in-cheek short stories by Isaac Asimov. The book also includes suggestions for using science fiction as an educational resource.

  8. Extended Wordsearches in Chemistry

    NASA Astrophysics Data System (ADS)

    Cotton, Simon

    1998-04-01

    Students can be encouraged to develop their factual knowledge by use of puzzles. One strategy described here is the extended wordsearch, where the wordsearch element generates a number of words or phrases from which the answers to a series of questions are selected. The wordsearch can be generated with the aid of computer programs, though in order to make them suitable for students with dyslexia or other learning difficulties, a simpler form is more appropriate. These problems can be employed in a variety of contexts, for example, as topic tests and classroom end-of-lesson fillers. An example is provided in the area of calcium chemistry. Sources of suitable software are listed.

  9. Phoenix's Wet Chemistry Lab

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is an illustration of soil analysis on NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL will attempt to determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  10. Phoenix's Wet Chemistry Lab

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is an illustration of the analytical procedure of NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL can determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  11. Solvents and sustainable chemistry

    PubMed Central

    Welton, Tom

    2015-01-01

    Solvents are widely recognized to be of great environmental concern. The reduction of their use is one of the most important aims of green chemistry. In addition to this, the appropriate selection of solvent for a process can greatly improve the sustainability of a chemical production process. There has also been extensive research into the application of so-called green solvents, such as ionic liquids and supercritical fluids. However, most examples of solvent technologies that give improved sustainability come from the application of well-established solvents. It is also apparent that the successful implementation of environmentally sustainable processes must be accompanied by improvements in commercial performance. PMID:26730217

  12. Sustainable chemistry metrics.

    PubMed

    Calvo-Flores, Francisco García

    2009-01-01

    Green chemistry has developed mathematical parameters to describe the sustainability of chemical reactions and processes, in order to quantify their environmental impact. These parameters are related to mass and energy magnitudes, and enable analyses and numerical diagnoses of chemical reactions. The environmental impact factor (E factor), atom economy, and reaction mass efficiency have been the most influential metrics, and they are interconnected by mathematical equations. The ecodesign concept must also be considered for complex industrial syntheses, as a part of the sustainability of manufacturing processes. The aim of this Concept article is to identify the main parameters for evaluating undesirable environmental consequences.

  13. USSR Report, Chemistry

    DTIC Science & Technology

    2007-11-02

    showing predominance of the P phase. Figures 1 ; references 4 (Western). [345-12172] UDC 541.71.28 CATALYTIC CONVERSION OF 1,1- DIMETHYLHYDRAZINE ON... dimethylhydrazine (I) on applied iridium catalyst Ir/Al20., (30% by wt.) was reported recently by the authors in reference 1 . Though the catalyst was...365006 JPRS-UCH-85-0 1 3 2 2 October 1985 USSR Report CHEMISTRY MBTmiraoirimSSff-jf DäfflMböäaa OBJira«««ä A9980729 070 FBIS JW1C

  14. USSR Report, Chemistry, No. 103

    DTIC Science & Technology

    1983-06-21

    The reports contains a variety of abstracts on research and development of USSR Chemistry with particular attention to coal gasification , fertilizers, organophosphorus compound synthesis, and polymerization.

  15. Green chemistry: principles and practice.

    PubMed

    Anastas, Paul; Eghbali, Nicolas

    2010-01-01

    Green Chemistry is a relatively new emerging field that strives to work at the molecular level to achieve sustainability. The field has received widespread interest in the past decade due to its ability to harness chemical innovation to meet environmental and economic goals simultaneously. Green Chemistry has a framework of a cohesive set of Twelve Principles, which have been systematically surveyed in this critical review. This article covers the concepts of design and the scientific philosophy of Green Chemistry with a set of illustrative examples. Future trends in Green Chemistry are discussed with the challenge of using the Principles as a cohesive design system (93 references).

  16. Inorganic Chemistry by Gary Wulfsberg

    NASA Astrophysics Data System (ADS)

    Ackermann, Martin N.

    2000-11-01

    Inorganic Chemistry is an interesting new option for teachers of advanced inorganic courses and offers the possibility of serving an introductory course as well. Since PDIC first appeared, more authors have adopted the approach of developing descriptive inorganic chemistry around common principles instead of a group-by-group treatment, which makes this text less of a departure from the traditional than PDIC was. Still, Wulfsberg offers an original and engaging perspective on inorganic chemistry. Even if this text is not adopted for a course, it deserves a place on the shelf of every teacher of inorganic chemistry, where it will be a valuable resource.

  17. Complex Protostellar Chemistry

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A., III; Johnson, Natasha M.

    2012-01-01

    Two decades ago, our understanding of the chemistry in protostars was simple-matter either fell into the central star or was trapped in planetary-scale objects. Some minor chemical changes might occur as the dust and gas fell inward, but such effects were overwhelmed by the much larger scale processes that occurred even in bodies as small as asteroids. The chemistry that did occur in the nebula was relatively easy to model because the fall from the cold molecular cloud into the growing star was a one-way trip down a well-known temperature-pressure gradient; the only free variable was time. However, just over 10 years ago it was suggested that some material could be processed in the inner nebula, flow outward, and become incorporated into comets (1, 2). This outward flow was confirmed when the Stardust mission returned crystalline mineral fragments (3) from Comet Wild 2 that must have been processed close to the Sun before they were incorporated into the comet. In this week's Science Express, Ciesla and Sandford (4) demonstrate that even the outermost regions of the solar nebula can be a chemically active environment. Their finding could have consequences for the rest of the nebula.

  18. Interstellar Grain Surface Chemistry

    NASA Technical Reports Server (NTRS)

    Tielens, Alexander G. G. M.; Cuzzi, Jeffrey N. (Technical Monitor)

    1995-01-01

    Chemistry on grain surfaces plays an Important role in the formation of interstellar Ices, It can also influence the composition of the gas phase through outgassing near luminous, newly formed stars. This paper reviews the chemical processes taking place on Interstellar grain surfaces with the emphasis on those transforming CO into other hydrocarbons. At low, molecular cloud temperatures (approximately equal to 10K), physisorption processes dominate interstellar grain surface chemistry and GO is largely hydrogenated through reactions with atomic H and oxidized through reactions with atomic O. The former will lead to the formation of H2CO and CH3OH ices, while the latter results in CO2 ice. The observational evidence for these ices in molecular clouds will be discussed. Very close to protostars, the gas and grain temperatures are much higher (approximately equal to 500K) and chemisorption processes, including catalytic surface reactions, becomes important. This will be illustrated based upon our studies of the Fischer-Tropsch Synthesis of CH4 from CO on metallic surfaces. Likely, this process has played an important role in the early solar nebula. Observational consequences will be pointed out.

  19. Medicinal Chemistry/Pharmacology in Sophomore Organic Chemistry.

    ERIC Educational Resources Information Center

    Harrison, Aline M.

    1989-01-01

    Discussed is a series of lectures designed to illustrate the use of general organic chemical principles in molecular biology, introduce current research in interdisciplinary areas to the beginner, increase interest in organic chemistry, and bridge the gap between traditional organic chemistry, biology, and the consumer. An outline is presented.…

  20. A New Chemistry Course for Non-Chemistry Majors.

    ERIC Educational Resources Information Center

    Ariel, Magda; And Others

    1982-01-01

    A two-semester basic chemistry course for nonchemistry engineering majors is described. First semester provides introductory chemistry for freshmen while second semester is "customer-oriented," based on a departmental choice of three out of six independent modules. For example, aeronautical engineering "customers" would select…

  1. Art in Chemistry: Chemistry in Art. Second Edition

    ERIC Educational Resources Information Center

    Greenberg, Barbara R.; Patterson, Dianne

    2008-01-01

    This textbook integrates chemistry and art with hands-on activities and fascinating demonstrations that enable students to see and understand how the science of chemistry is involved in the creation of art. It investigates such topics as color integrated with electromagnetic radiation, atoms, and ions; paints integrated with classes of matter,…

  2. A Quantum Chemistry Concept Inventory for Physical Chemistry Classes

    ERIC Educational Resources Information Center

    Dick-Perez, Marilu; Luxford, Cynthia J.; Windus, Theresa L.; Holme, Thomas

    2016-01-01

    A 14-item, multiple-choice diagnostic assessment tool, the quantum chemistry concept inventory or QCCI, is presented. Items were developed based on published student misconceptions and content coverage and then piloted and used in advanced physical chemistry undergraduate courses. In addition to the instrument itself, data from both a pretest,…

  3. Introducing Chemistry Students to the "Real World" of Chemistry

    ERIC Educational Resources Information Center

    Brown, Michael E.; Cosser, Ronald C.; Davies-Coleman, Michael T.; Kaye, Perry T.; Klein, Rosalyn; Lamprecht, Emmanuel; Lobb, Kevin; Nyokong, Tebello; Sewry, Joyce D.; Tshentu, Zenixole R.; van der Zeyde, Tino; Watkins, Gareth M.

    2010-01-01

    A majority of chemistry graduates seek employment in a rapidly changing chemical industry. Our attempts to provide the graduates with skills in entrepreneurship and the ability to understand and communicate with their chemical engineering colleagues, in addition to their fundamental knowledge of chemistry, are described. This is done at…

  4. Influencing College Chemistry Success through High School Chemistry Teaching

    ERIC Educational Resources Information Center

    Tai, Robert H.; Sadler, Philip M.; Loehr, John F.

    2006-01-01

    The connection between high school chemistry pedagogical experiences and introductory college chemistry performance has been a topic researched in published science education literature since the 1920s. However, analysis techniques have limited the generalizability of these results. This review discusses the findings of a large-scale,…

  5. Clinical chemistry through Clinical Chemistry: a journal timeline.

    PubMed

    Rej, Robert

    2004-12-01

    The establishment of the modern discipline of clinical chemistry was concurrent with the foundation of the journal Clinical Chemistry and that of the American Association for Clinical Chemistry in the late 1940s and early 1950s. To mark the 50th volume of this Journal, I chronicle and highlight scientific milestones, and those within the discipline, as documented in the pages of Clinical Chemistry. Amazing progress has been made in the field of laboratory diagnostics over these five decades, in many cases paralleling-as well as being bolstered by-the rapid pace in the development of computer technologies. Specific areas of laboratory medicine particularly well represented in Clinical Chemistry include lipids, endocrinology, protein markers, quality of laboratory measurements, molecular diagnostics, and general advances in methodology and instrumentation.

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

    PubMed

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

    2015-06-12

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

  7. Significant steps in the evolution of analytical chemistry--is the today's analytical chemistry only chemistry?

    PubMed

    Karayannis, Miltiades I; Efstathiou, Constantinos E

    2012-12-15

    In this review the history of chemistry and specifically the history and the significant steps of the evolution of analytical chemistry are presented. In chronological time spans, covering the ancient world, the middle ages, the period of the 19th century, and the three evolutional periods, from the verge of the 19th century to contemporary times, it is given information for the progress of chemistry and analytical chemistry. During this period, analytical chemistry moved gradually from its pure empirical nature to more rational scientific activities, transforming itself to an autonomous branch of chemistry and a separate discipline. It is also shown that analytical chemistry moved gradually from the status of exclusive serving the chemical science, towards serving, the environment, health, law, almost all areas of science and technology, and the overall society. Some recommendations are also directed to analytical chemistry educators concerning the indispensable nature of knowledge of classical analytical chemistry and the associated laboratory exercises and to analysts, in general, why it is important to use the chemical knowledge to make measurements on problems of everyday life.

  8. Chemistry laboratory safety manual available

    NASA Technical Reports Server (NTRS)

    Elsbrock, R. G.

    1968-01-01

    Chemistry laboratory safety manual outlines safe practices for handling hazardous chemicals and chemistry laboratory equipment. Included are discussions of chemical hazards relating to fire, health, explosion, safety equipment and procedures for certain laboratory techniques and manipulations involving glassware, vacuum equipment, acids, bases, and volatile solvents.

  9. USSR Report, Chemistry, No. 105

    DTIC Science & Technology

    2007-11-02

    This USSR Report contains articles on Chemistry. Some of the topics covered are Alkaloids, Catalysis, Analytical Chemistry, Chemical Industry, Coal Gasification , Combustion, Electrochemistry, Fertilizers, Free Radials, Nitrogen Compounds, Organometallic Compounds, Organophosphorus Compounds, Pesticides, Petroleum Processing Technology, Polymers and Polymerization and Rubber and Elastomers.,

  10. Crocodile Chemistry. [CD-ROM].

    ERIC Educational Resources Information Center

    1999

    This high school chemistry resource is an on-screen chemistry lab. In the program, students can experiment with a huge range of chemicals, choosing the form, quantity and concentrations. Dangerous or difficult experiments can be investigated safely and easily. A vast range of equipment can be set up, and complex simulations can be put together and…

  11. Plasma chemistry and its applications

    NASA Technical Reports Server (NTRS)

    Hozumi, K.

    1980-01-01

    The relationship between discharge phenomena and plasma chemistry, as well as the equipment and mechanisms of plasma chemical reactions are described. Various areas in which plasma chemistry is applied are surveyed, such as: manufacturing of semiconductor integrated circuits; synthetic fibers; high polymer materials for medical uses; optical lenses; and membrane filters (reverse penetration films).

  12. Contextualising Nanotechnology in Chemistry Education

    ERIC Educational Resources Information Center

    O'Connor, Christine; Hayden, Hugh

    2008-01-01

    In recent years nanotechnology has become part of the content of many undergraduate chemistry and physics degree courses. This paper deals with the role of contextualisation of nanotechnology in the delivery of the content, as nanotechnology is only now being slowly integrated into many chemistry degree courses in Ireland and elsewhere. An…

  13. Chemistry and the Liberal Arts

    ERIC Educational Resources Information Center

    Strong, Laurence E.

    1971-01-01

    Argues that chemistry has major implications for our understanding of the nature of things including ourselves. Illustrations have been drawn from the chemical elements, chemical equilibria, and chemical entropy. Chemistry should not be presented as something justified only by its practical results while the other sciences raise the ultimate…

  14. Organic Chemistry Software from COMPress.

    ERIC Educational Resources Information Center

    Ball, Sister Isabel

    1982-01-01

    Reviews three organic chemistry computer programs for TRS-80 and Apple microcomputers. Programs include "Introduction to Organic Chemistry,""Qualitative Organic Analysis," and a game called "Chemrain." Indicates that all three produce a readable screen, require exact responses, use graphics in an appealingly and…

  15. The Great Ideas of Chemistry.

    ERIC Educational Resources Information Center

    Gillespie, Ronald J.

    1997-01-01

    Presents a list of six concepts that form the basis of modern chemistry and that should be included in introductory chemistry courses. Discusses atoms, molecules, and ions; the chemical bond; molecular shape and geometry; kinetic theory; the chemical reaction; and energy and entropy. (JRH)

  16. Organic Chemistry for the Gifted.

    ERIC Educational Resources Information Center

    deBeer, W. H. J.

    In response to a serious shortage of chemists in South Africa, gifted secondary school students are enrolled in an enrichment program in organic chemistry and encouraged to consider chemistry or one of its related fields as a career. The introductory portion of the program involves approximately 90 hours over a 3-year period while the advanced…

  17. Introducing Relativity into Quantum Chemistry

    ERIC Educational Resources Information Center

    Li, Wai-Kee; Blinder, S. M.

    2011-01-01

    It is not often realized by chemists that the special theory of relativity is behind several aspects of quantum chemistry. The Schrdinger equation itself is based on relations between space-time and energy-momentum four vectors. Electron spin is, of course, the most obvious manifestation of relativity. The chemistry of some heavy elements is…

  18. Turbulent Mixing Chemistry in Disks

    NASA Astrophysics Data System (ADS)

    Semenov, D.; Wiebe, D.

    2006-11-01

    A gas-grain chemical model with surface reaction and 1D/2D turbulent mixing is available for protoplanetary disks and molecular clouds. Current version is based on the updated UMIST'95 database with gas-grain interactions (accretion, desorption, photoevaporation, etc.) and modified rate equation approach to surface chemistry (see also abstract for the static chemistry code).

  19. News from Online: Green Chemistry

    ERIC Educational Resources Information Center

    Uffelman, Erich S.

    2004-01-01

    Green chemistry closely relates to energy and environmental problems, and includes the promotion of environmental friendly products and systems within the framework of renewable resources. Various websites on green chemistry are reviewed, one of which lists the 12 commandments of this particular subject.

  20. Rethinking Undergraduate Physical Chemistry Curricula

    ERIC Educational Resources Information Center

    Miller, Stephen R.

    2016-01-01

    A summary of fundamental changes made to the undergraduate physical chemistry curriculum in the Chemistry Department at Gustavus Adolphus College (beginning in the 2013-2014 academic year) is presented. The yearlong sequence now consists of an introductory semester covering both quantum mechanics and thermodynamics/kinetics, followed by a second…

  1. Remedial Mathematics for Quantum Chemistry

    ERIC Educational Resources Information Center

    Koopman, Lodewijk; Brouwer, Natasa; Heck, Andre; Buma, Wybren Jan

    2008-01-01

    Proper mathematical skills are important for every science course and mathematics-intensive chemistry courses rely on a sound mathematical pre-knowledge. In the first-year quantum chemistry course at this university, it was noticed that many students lack basic mathematical knowledge. To tackle the mathematics problem, a remedial mathematics…

  2. Chemistry Teachers' Views of Creativity

    ERIC Educational Resources Information Center

    Akkanat, Çigdem; Gökdere, Murat

    2015-01-01

    The purpose of this study was to determine chemistry teachers' views of creativity. In this study, phenomenology method, one of the qualitative research patterns, was used. The participants of this study were 13 chemistry teachers working in Amasya. A semi-structured interview form was used for data collection. By using NVivo 9 qualitative…

  3. Local Evaluation of Chemistry Journals

    ERIC Educational Resources Information Center

    Kraus, Joseph R.; Hansen, Rachel

    2008-01-01

    This paper reports on the evaluation of local usage statistics of a specific set of chemistry journals at the University of Denver in Colorado, USA. The objective of the study is to demonstrate that commercial publishers in chemistry charge considerably more for their journals than those from the non-commercial sector. There are three variables…

  4. Stereochemical Control in Carbohydrate Chemistry

    ERIC Educational Resources Information Center

    Batchelor, Rhys; Northcote, Peter T.; Harvey, Joanne E.; Dangerfield, Emma M.; Stocker, Bridget L.

    2008-01-01

    Carbohydrates, in the form of glycoconjugates, have recently been shown to control a wide range of cellular processes. Accordingly, students interested in the study of organic chemistry and biomedical sciences should be exposed to carbohydrate chemistry. To this end, we have developed a sequence of experiments that leads the student from the…

  5. Fundamentals of Aqueous Microwave Chemistry

    EPA Science Inventory

    The first chemical revolution changed modern life with a host of excellent amenities and services, but created serious problems related to environmental pollution. After 150 years of current chemistry principles and practices, we need a radical change to a new type of chemistry k...

  6. Chemical Principles Revisited: Petroleum Chemistry.

    ERIC Educational Resources Information Center

    Kolb, Doris; Kolb, Kenneth E.

    1979-01-01

    Presents an historical review of the role of petroleum in world history and information on the chemistry of petroleum. It is suggested that petroleum chemistry be discussed since within the next two decades oil and gas will provide the major portion of U.S. energy. (Author/SA)

  7. Dynamic imine chemistry.

    PubMed

    Belowich, Matthew E; Stoddart, J Fraser

    2012-03-21

    Formation of an imine--from an amine and an aldehyde--is a reversible reaction which operates under thermodynamic control such that the formation of kinetically competitive intermediates are, in the fullness of time, replaced by the thermodynamically most stable product(s). For this fundamental reason, the imine bond has emerged as an extraordinarily diverse and useful one in the hands of synthetic chemists. Imine bond formation is one of a handful of reactions which define a discipline known as dynamic covalent chemistry (DCC), which is now employed widely in the construction of exotic molecules and extended structures on account of the inherent 'proof-reading' and 'error-checking' associated with these reversible reactions. While both supramolecular chemistry and DCC operate under the regime of reversibility, DCC has the added advantage of constructing robust molecules on account of the formation of covalent bonds rather than fragile supermolecules resulting from noncovalent bonding interactions. On the other hand, these products tend to require more time to form--sometimes days or even months--but their formation can often be catalysed. In this manner, highly symmetrical molecules and extended structures can be prepared from relatively simple precursors. When DCC is utilised in conjunction with template-directed protocols--which rely on the use of noncovalent bonding interactions between molecular building blocks in order to preorganise them into certain relative geometries as a prelude to the formation of covalent bonds under equilibrium control--an additional level of control of structure and topology arises which offers a disarmingly simple way of constructing mechanically-interlocked molecules, such as rotaxanes, catenanes, Borromean rings, and Solomon knots. This tutorial review focuses on the use of dynamic imine bonds in the construction of compounds and products formed with and without the aid of additional templates. While synthesis under thermodynamic

  8. Chemistry of Art and Color Sudoku Puzzles

    ERIC Educational Resources Information Center

    Welsh, Michael J.

    2007-01-01

    Sudoku puzzle format was used to teach light science and chemistry terms to students of Chemistry of Art and Color. The puzzles were used to motivate and encourage students to learn chemistry in an easier and in friendly fashion.

  9. Stereospecific ligands and their complexes. Part XII. Synthesis, characterization and in vitro antiproliferative activity of platinum(IV) complexes with some O,O‧-dialkyl esters of (S,S)-ethylenediamine-N,N‧-di-2-propanoic acid against colon cancer (HCT-116) and breast cancer (MDA-MB-231) cell lines

    NASA Astrophysics Data System (ADS)

    Stojković, Danijela Lj.; Jevtić, Verica V.; Radić, Gordana P.; Đačić, Dragana S.; Ćurčić, Milena G.; Marković, Snežana D.; Ðinović, Vesna M.; Petrović, Vladimir P.; Trifunović, Srećko R.

    2014-03-01

    Synthesis of three new platinum(IV) complexes C1-C3, with bidentate N,N‧-ligand precursors, O,O‧-dialkyl esters (alkyl = propyl, butyl and pentyl), of (S,S)-ethylenediamine-N,N‧-di-2-propanoic acid, H2-S,S-eddp were reported. The reported platinum(IV) complexes characterized by elemental analysis and their structures were discussed on the bases of their infrared, 1H and 13C NMR spectroscopy. In vitro antiproliferative activity was determined on tumor cell lines: human colon carcinoma HCT-116 and human breast carcinoma MDA-MB-231, using MTT test.

  10. Lessons for Introductory Chemistry

    NASA Astrophysics Data System (ADS)

    Martin, John S.; Blackburn, Edward V.

    2000-07-01

    These twelve lessons, and an introductory lesson, are tutorials in basic topics of introductory chemistry. They are suitable for school use, individual study, or distance learning. They are particularly valuable as review material for students in more advanced courses who may have been away from the subject for some time. They contain a great variety of problems and exercises driven by random-number generators, so that the same problem never repeats exactly. The lessons are, for the most part, Socratic dialogues in which the student is required to answer questions and perform simulated experiments in order to discover chemical principles. They are organized in an intuitive chapter and page structure. One may move readily around each lesson. There are many on-screen facilities such as help, data tables, and a calculator.

  11. Advances in analytical chemistry

    NASA Technical Reports Server (NTRS)

    Arendale, W. F.; Congo, Richard T.; Nielsen, Bruce J.

    1991-01-01

    Implementation of computer programs based on multivariate statistical algorithms makes possible obtaining reliable information from long data vectors that contain large amounts of extraneous information, for example, noise and/or analytes that we do not wish to control. Three examples are described. Each of these applications requires the use of techniques characteristic of modern analytical chemistry. The first example, using a quantitative or analytical model, describes the determination of the acid dissociation constant for 2,2'-pyridyl thiophene using archived data. The second example describes an investigation to determine the active biocidal species of iodine in aqueous solutions. The third example is taken from a research program directed toward advanced fiber-optic chemical sensors. The second and third examples require heuristic or empirical models.

  12. Prebiotic chemistry in clouds

    NASA Technical Reports Server (NTRS)

    Oberbeck, Verne R.; Marshall, John; Shen, Thomas

    1991-01-01

    The chemical evolution hypothesis of Woese (1979), according to which prebiotic reactions occurred rapidly in droplets in giant atmospheric reflux columns was criticized by Scherer (1985). This paper proposes a mechanism for prebiotic chemistry in clouds that answers Scherer's concerns and supports Woese's hypothesis. According to this mechanism, rapid prebiotic chemical evolution was facilitated on the primordial earth by cycles of condensation and evaporation of cloud drops containing clay condensation nuclei and nonvolatile monomers. For example, amino acids supplied by, or synthesized during entry of meteorites, comets, and interplanetary dust, would have been scavenged by cloud drops containing clay condensation nuclei and would be polymerized within cloud systems during cycles of condensation, freezing, melting, and evaporation of cloud drops.

  13. Clays in prebiological chemistry

    NASA Technical Reports Server (NTRS)

    Rao, M.; Oro, J.; Odom, D. G.

    1980-01-01

    The ways in which clays have been utilized in studies of prebiological chemistry are reviewed, and an assessment is given of the possible role of clays in prebiological systems. The adsorption of organic molecules on clays has been demonstrated, as has the synthesis of bioorganic monomers in the presence of clays. For instance, amino acids, purines and pyrimidines have been obtained from carbon monoxide and nitric acid in the presence of clays at relatively high temperatures (250-325 C). The oligomerization of biochemical monomers, mediated by clays, has also been shown to result in the formation of polymer molecules basic to life. Clays have also been found to affect the condensation of mononucleotides to oligonucleotides.

  14. Biosensors in clinical chemistry.

    PubMed

    D'Orazio, Paul

    2003-08-01

    Biosensors are analytical devices composed of a recognition element of biological origin and a physico-chemical transducer. The biological element is capable of sensing the presence, activity or concentration of a chemical analyte in solution. The sensing takes place either as a binding event or a biocatalytical event. These interactions produce a measurable change in a solution property, which the transducer converts into a quantifiable electrical signal. Present-day applications of biosensors to clinical chemistry are reviewed, including basic and applied research, commercial applications and fabrication techniques. Recognition elements include enzymes as biocatalytic recognition elements and immunoagents and DNA segments as affinity ligand recognition elements, coupled to electrochemical and optical modes of transduction. The future will include biosensors based on synthetic recognition elements to allow broad applicability to different classes of analytes and modes of transduction extending lower limits of sensitivity. Microfabrication will permit biosensors to be constructed as arrays and incorporated into lab-on-a-chip devices.

  15. Ionospheric chemistry of NO(+)

    NASA Technical Reports Server (NTRS)

    Breig, E. L.; Hanson, W. B.; Hoffman, J. H.

    1984-01-01

    An investigation is described of the behavior of NO(+) in the daytime F region, with basic ion concentration measurements from the Atmosphere Explorer C satellite. The data set was acquired along select orbits at low latitudes and exhibits substantial variations in the NO(+) concentration, both along and between nearby orbits. An excellent consistency is demonstrated between these observations and current chemical equilibrium theory, in contrast to differences that have been reported for the related N2(+) ion. Large variations in the concurrently observed electron temperature permit a relevant comparison between different laboratory determinations of the dissociative recombination rate coefficient. Contributions to the NO(+) production from several secondary sources are also evaluated. Results strengthen the basis for the current theoretical ionospheric chemistry of NO(+) and establish important constraints on resolution of the difficulties with N2(+).

  16. Nanoplasmonics tuned "click chemistry".

    PubMed

    Tijunelyte, I; Guenin, E; Lidgi-Guigui, N; Colas, F; Ibrahim, J; Toury, T; Lamy de la Chapelle, M

    2016-04-07

    Nanoplasmonics is a growing field of optical condensed matter science dedicated to optical phenomena at the nanoscale level in metal systems. Extensive research on noble metallic nanoparticles (NPs) has emerged within the last two decades due to their ability to keep the optical energy concentrated in the vicinity of NPs, in particular, the ability to create optical near-field enhancement followed by heat generation. We have exploited these properties in order to induce a localised "click" reaction in the vicinity of gold nanostructures under unfavourable experimental conditions. We demonstrate that this reaction can be controlled by the plasmonic properties of the nanostructures and we propose two physical mechanisms to interpret the observed plasmonic tuning of the "click" chemistry.

  17. Prebiotic phosphorus chemistry reconsidered

    NASA Technical Reports Server (NTRS)

    Schwartz, A. W.; Orgel, L. E. (Principal Investigator)

    1997-01-01

    The available evidence indicates that the origin of life on Earth certainly occurred earlier than 3.5 billion years ago and perhaps substantially earlier. The time available for the chemical evolution which must have preceded this event is more difficult to estimate. Both endogenic and exogenic contributions to chemical evolution have been considered; i.e., from chemical reactions in a primitive atmosphere, or by introduction in the interiors of comets and/or meteorites. It is argued, however, that the phosphorus chemistry of Earth's earliest hydrosphere, whether primarily exogenic or endogenic in origin, was most likely dominated by compounds less oxidized than phosphoric acid and its esters. A scenario is presented for the early production of a suite of reactive phosphonic acid derivatives, the properties of which may have foreshadowed the later appearance of biophosphates.

  18. Bias in clinical chemistry.

    PubMed

    Theodorsson, Elvar; Magnusson, Bertil; Leito, Ivo

    2014-01-01

    Clinical chemistry uses automated measurement techniques and medical knowledge in the interest of patients and healthy subjects. Automation has reduced repeatability and day-to-day variation considerably. Bias has been reduced to a lesser extent by reference measurement systems. It is vital to minimize clinically important bias, in particular bias within conglomerates of laboratories that measure samples from the same patients. Small and variable bias components will over time show random error properties and conventional random-error based methods for calculating measurement uncertainty can then be applied. The present overview of bias presents the general principles of error and uncertainty concepts, terminology and analysis, and suggests methods to minimize bias and measurement uncertainty in the interest of healthcare.

  19. Chemistry of Aviation Fuels

    NASA Technical Reports Server (NTRS)

    Knepper, Bryan; Hwang, Soon Muk; DeWitt, Kenneth J.

    2004-01-01

    Minimum ignition energies of various methanol/air mixtures were measured in a temperature controlled constant volume combustion vessel using a spark ignition method with a spark gap distance of 2 mm. The minimum ignition energies decrease rapidly as the mixture composition (equivalence ratio, Phi) changes from lean to stoichiometric, reach a minimum value, and then increase rather slowly with Phi. The minimum of the minimum ignition energy (MIE) and the corresponding mixture composition were determined to be 0.137 mJ and Phi = 1.16, a slightly rich mixture. The variation of minimum ignition energy with respect to the mixture composition is explained in terms of changes in reaction chemistry.

  20. Frontiers in polymer chemistry.

    PubMed

    Schlüter, A Dieter

    2013-01-01

    The article shows how the initial concept of Staudinger on linear macromolecules was expanded topologically by increasing the cross-section diameter of polymer chains and by introducing sheet polymers with planar rather than the commonly known linear repeat units. The two concrete projects addressed are the synthesis of dendronized and of two-dimensional polymers. It is explained how these novel macromolecules were achieved and which obstacles had to be overcome but also where these frontiers in polymer chemistry might lead to new insights in polymer science in general and novel applications in particular. The article also provides insights into analytical issues because both target macromolecules are in an extraordinarily high molar mass range and contrast/sensitivity issues can turn rather serious in particular for the two-dimensional polymers.

  1. Ion chemistry in space.

    PubMed

    Larsson, M; Geppert, W D; Nyman, G

    2012-06-01

    We review the gas-phase chemistry in extraterrestrial space that is driven by reactions with atomic and molecular ions. Ions are ubiquitous in space and are potentially responsible for the formation of increasingly complex interstellar molecules. Until recently, positively charged atoms and molecules were the only ions known in space; however, this situation has changed with the discovery of various molecular anions. This review covers not only the observation, distribution and reactions of ions in space, but also laboratory-based experimental and theoretical methods for studying these ions. Recent results from space-based instruments, such as those on the Cassini-Huygens space mission and the Herschel Space Observatory, are highlighted.

  2. Chemistry in Titan

    NASA Astrophysics Data System (ADS)

    Plessis, S.; Carrasco, N.; Pernot, P.

    2009-04-01

    Modelling the chemical composition of Titan's ionosphere is a very challenging issue. Latest works perform either inversion of CASSINI's INMS mass spectra (neutral[1] or ion[2]), or design coupled ion-neutral chemistry models[3]. Coupling ionic and neutral chemistry has been reported to be an essential feature of accurate modelling[3]. Electron Dissociative Recombination (EDR), where free electrons recombine with positive ions to produce neutral species, is a key component of ion-neutral coupling. There is a major difficulty in EDR modelling: for heavy ions, the distribution of neutral products is incompletely characterized by experiments. For instance, for some hydrocarbon ions only the carbon repartition is measured, leaving the hydrogen repartition and thus the exact neutral species identity unknown[4]. This precludes reliable deterministic modelling of this process and of ion-neutral coupling. We propose a novel stochastic description of the EDR chemical reactions which enables efficient representation and simulation of the partial experimental knowledge. The description of products distribution in multi-pathways reactions is based on branching ratios, which should sum to unity. The keystone of our approach is the design of a probability density function accounting for all available informations and physical constrains. This is done by Dirichlet modelling which enables one to sample random variables whose sum is constant[5]. The specifics of EDR partial uncertainty call for a hierarchiral Dirichlet representation, which generalizes our previous work[5]. We present results on the importance of ion-neutral coupling based on our stochastic model. C repartition H repartition (measured) (unknown ) → C4H2 + 3H2 + H .. -→ C4 . → C4H2 + 7H → C3H8. + CH C4H+9 + e- -→ C3 + C .. → C3H3 + CH2 + 2H2 → C2H6 + C2H2 + H .. -→ C2 + C2 . → 2C2H2 + 2H2 + H (1) References [1] J. Cui, R.V. Yelle, V. Vuitton, J.H. Waite Jr., W.T. Kasprzak

  3. Atmospheric Pseudohalogen Chemistry

    NASA Technical Reports Server (NTRS)

    Lary, David John

    2004-01-01

    Hydrogen cyanide is not usually considered in atmospheric chemical models. The paper presents three reasons why hydrogen cyanide is likely to be significant for atmospheric chemistry. Firstly, HCN is a product and marker of biomass burning. Secondly, it is also likely that lightning is producing HCN, and as HCN is sparingly soluble it could be a useful long-lived "smoking gun" marker of lightning activity. Thirdly, the chemical decomposition of HCN leads to the production of small amounts of the cyanide (CN) and NCO radicals. The NCO radical can be photolyzed in the visible portion of the spectrum yielding nitrogen atoms (N). The production of nitrogen atoms is significant as it leads to the titration of total nitrogen from the atmosphere via N+N->N2, where N2 is molecular nitrogen.

  4. Getting Hooked on Chemistry

    NASA Astrophysics Data System (ADS)

    Mason, Diana S.

    2002-04-01

    Other fun things in this issue include three Quote Boxes by Olney (3) that will allow your students to engage in deductive reasoning to solve the puzzles. Kelkar (4) presents a slightly more difficult but very clever mystery element game; it provides clues to element symbols that all fit into a single matrix. Ibanez's game (5) lists popular sayings or proverbs and the student's job is to match each with an analogous chemical phenomenon. As always, answers are provided. For the more sophisticated among us, there is Who Wants to Be a Chemist Extraordinaire? devised by Campbell and Muzyka (6), who describe their use of online chemistry game shows patterned on popular TV programs. Examples of the HTML files with sample questions are available through JCE Online. These are just some of the many suggestions that can be found in this issue of JCE. Try a few, you might like them!

  5. Organic chemistry on Titan

    NASA Technical Reports Server (NTRS)

    Chang, S.; Scattergood, T.; Aronowitz, S.; Flores, J.

    1979-01-01

    Features taken from various models of Titan's atmosphere are combined in a working composite model that provides environmental constraints within which different pathways for organic chemical synthesis are determined. Experimental results and theoretical modeling suggest that the organic chemistry of the satellite is dominated by two processes: photochemistry and energetic particle bombardment. Photochemical reactions of CH4 in the upper atmosphere can account for the presence of C2 hydrocarbons. Reactions initiated at various levels of the atmosphere by cosmic rays, Saturn 'wind', and solar wind particle bombardment of a CH4-N2 atmospheric mixture can account for the UV-visible absorbing stratospheric haze, the reddish appearance of the satellite, and some of the C2 hydrocarbons. In the lower atmosphere photochemical processes will be important if surface temperatures are sufficiently high for gaseous NH3 to exist. It is concluded that the surface of Titan may contain ancient or recent organic matter (or both) produced in the atmosphere.

  6. Nanoplasmonics tuned ``click chemistry''

    NASA Astrophysics Data System (ADS)

    Tijunelyte, I.; Guenin, E.; Lidgi-Guigui, N.; Colas, F.; Ibrahim, J.; Toury, T.; Lamy de La Chapelle, M.

    2016-03-01

    Nanoplasmonics is a growing field of optical condensed matter science dedicated to optical phenomena at the nanoscale level in metal systems. Extensive research on noble metallic nanoparticles (NPs) has emerged within the last two decades due to their ability to keep the optical energy concentrated in the vicinity of NPs, in particular, the ability to create optical near-field enhancement followed by heat generation. We have exploited these properties in order to induce a localised ``click'' reaction in the vicinity of gold nanostructures under unfavourable experimental conditions. We demonstrate that this reaction can be controlled by the plasmonic properties of the nanostructures and we propose two physical mechanisms to interpret the observed plasmonic tuning of the ``click'' chemistry.Nanoplasmonics is a growing field of optical condensed matter science dedicated to optical phenomena at the nanoscale level in metal systems. Extensive research on noble metallic nanoparticles (NPs) has emerged within the last two decades due to their ability to keep the optical energy concentrated in the vicinity of NPs, in particular, the ability to create optical near-field enhancement followed by heat generation. We have exploited these properties in order to induce a localised ``click'' reaction in the vicinity of gold nanostructures under unfavourable experimental conditions. We demonstrate that this reaction can be controlled by the plasmonic properties of the nanostructures and we propose two physical mechanisms to interpret the observed plasmonic tuning of the ``click'' chemistry. Electronic supplementary information (ESI) available: NMR study on reaction initiation, SERS spectra and temperature calculations. See DOI: 10.1039/c5nr09018k

  7. Chemistry for whom? Gender awareness in teaching and learning chemistry

    NASA Astrophysics Data System (ADS)

    Andersson, Kristina

    2016-11-01

    Marie Ståhl and Anita Hussénius have defined what discourses dominate national tests in chemistry for Grade 9 in Sweden by using feminist, critical didactic perspectives. This response seeks to expand the results in Ståhl and Hussénius's article Chemistry inside an epistemological community box!—Discursive exclusions and inclusions in the Swedish national tests in chemistry, by using different facets of gender awareness. The first facet—Gender awareness in relations to the test designers' own conceptions—highlighted how the gender order where women are subordinated men becomes visible in the national tests as a consequence of the test designers internalized conceptions. The second facet—Gender awareness in relation to chemistry—discussed the hierarchy between discourses within chemistry. The third facet—Gender awareness in relation to students—problematized chemistry in relation to the students' identity formation. In summary, I suggest that the different discourses can open up new ways to interpret chemistry and perhaps dismantle the hegemonic chemistry discourse.

  8. JPRS Report, Science & Technology, USSR: Chemistry

    DTIC Science & Technology

    2007-11-02

    This report contains foreign media information from the USSR concerning analytical chemistry, electrochemistry, environmental chemistry, inorganic compounds, organophosphorous compounds, petroleum coal processing and polymers.

  9. JPRS Report, Science & Technology, USSR: Chemistry

    DTIC Science & Technology

    2007-11-02

    This report contains foreign media information from the USSR concerning analytical chemistry, catalysis, electrochemistry, inorganic compounds, organometallic compounds, organophosphorous compounds, polymers and radiation chemistry.

  10. JPRS Report, Science & Technology, USSR: Chemistry.

    DTIC Science & Technology

    2007-11-02

    Partial Contents: Catalysis, Chemical Industry, Electrochemistry, Environmental Chemistry, Materials Research, Organophosphorous Compounds, Petroleum and Coal Processing, Polymers and Rubber, Radiation Chemistry.

  11. Two-Year Community College Chemistry: Joules

    ERIC Educational Resources Information Center

    Bardole, Ellen, Ed.; Bardole, Jay, Ed.

    1978-01-01

    Discusses a self-paced individualized general chemistry laboratory, the Doctor of Arts program, the Educational Resources Information Center (ERIC) system, and problems existing in chemistry education. (SL)

  12. Incorporation of Medicinal Chemistry into the Organic Chemistry Curriculum

    ERIC Educational Resources Information Center

    Forbes, David C.

    2004-01-01

    Application of concepts presented in organic chemistry lecture using a virtual project involving the sythesis of medicinally important compounds is emphasized. The importance of reinforcing the concepts from lecture in lab, thus providing a powerful instructional means is discussed.

  13. Prebiotic chemistry in clouds.

    PubMed

    Oberbeck, V R; Marshall, J; Shen, T

    1991-01-01

    In the traditional concept for the origin of life as proposed by Oparin and Haldane in the 1920s, prebiotic reactants became slowly concentrated in the primordial oceans and life evolved slowly from a series of highly protracted chemical reactions during the first billion years of Earth's history. However, chemical evolution may not have occurred continuously because planetesimals and asteroids impacted the Earth many times during the first billion years, may have sterilized the Earth, and required the process to start over. A rapid process of chemical evolution may have been required in order that life appeared at or before 3.5 billion years ago. Thus, a setting favoring rapid chemical evolution may be required. A chemical evolution hypothesis set forth by Woese in 1979 accomplished prebiotic reactions rapidly in droplets in giant atmospheric reflux columns. However, in 1985 Scherer raised a number of objections to Woese's hypothesis and concluded that it was not valid. We propose a mechanism for prebiotic chemistry in clouds that satisfies Scherer's concerns regarding the Woese hypothesis and includes advantageous droplet chemistry. Prebiotic reactants were supplied to the atmosphere by comets, meteorites, and interplanetary dust or synthesized in the atmosphere from simple compounds using energy sources such as ultraviolet light, corona discharge, or lightning. These prebiotic monomers would have first encountered moisture in cloud drops and precipitation. We propose that rapid prebiotic chemical evolution was facilitated on the primordial Earth by cycles of condensation and evaporation of cloud drops containing clay condensation nuclei and nonvolatile monomers. For example, amino acids supplied by , or synthesized during entry of, meteorites, comets, and interplanetary dust would have been scavenged by cloud drops containing clay condensation nuclei. Polymerization would have occurred within cloud systems during cycles of condensation, freezing, melting, and

  14. Computational chemistry research

    NASA Technical Reports Server (NTRS)

    Levin, Eugene

    1987-01-01

    Task 41 is composed of two parts: (1) analysis and design studies related to the Numerical Aerodynamic Simulation (NAS) Extended Operating Configuration (EOC) and (2) computational chemistry. During the first half of 1987, Dr. Levin served as a member of an advanced system planning team to establish the requirements, goals, and principal technical characteristics of the NAS EOC. A paper entitled 'Scaling of Data Communications for an Advanced Supercomputer Network' is included. The high temperature transport properties (such as viscosity, thermal conductivity, etc.) of the major constituents of air (oxygen and nitrogen) were correctly determined. The results of prior ab initio computer solutions of the Schroedinger equation were combined with the best available experimental data to obtain complete interaction potentials for both neutral and ion-atom collision partners. These potentials were then used in a computer program to evaluate the collision cross-sections from which the transport properties could be determined. A paper entitled 'High Temperature Transport Properties of Air' is included.

  15. Computational Chemistry and Lubrication

    NASA Technical Reports Server (NTRS)

    Zehe, Michael J.

    1998-01-01

    Members of NASA Lewis Research Center's Tribology and Surface Science Branch are applying high-level computational chemistry techniques to the development of new lubrication systems for space applications and for future advanced aircraft engines. The next generation of gas turbine engines will require a liquid lubricant to function at temperatures in excess of 350 C in oxidizing environments. Conventional hydrocarbon-based lubricants are incapable of operating in these extreme environments, but a class of compounds known as the perfluoropolyether (PFAE) liquids (see the preceding illustration) shows promise for such applications. These commercially available products are already being used as lubricants in conditions where low vapor pressure and chemical stability are crucial, such as in satellite bearings and composite disk platters. At higher temperatures, however, these compounds undergo a decomposition process that is assisted (catalyzed) by metal and metal oxide bearing surfaces. This decomposition process severely limits the applicability of PFAE's at higher temperatures. A great deal of laboratory experimentation has revealed that the extent of fluid degradation depends on the chemical properties of the bearing surface materials. Lubrication engineers would like to understand the chemical breakdown mechanism to design a less vulnerable PFAE or to develop a chemical additive to block this degradation.

  16. Cometary MHD and chemistry

    NASA Technical Reports Server (NTRS)

    Wegmann, R.; Schmidt, H. U.; Huebner, W. F.; Boice, D. C.

    1987-01-01

    An MHD and chemical comet-coma model was developed, applying the computer program of Huebner (1985) for the detailed chemical evolution of a spherically expanding coma and the program of Schmidt and Wegman (1982) and Wegman (1987) for the MHD flow of plasma and magnetic field in a comet to the Giotto-mission data on the ion abundances measured by the HIS ion mass spectrometer. The physics and chemistry of the coma are modeled in great detail, including photoprocesses, gas-phase chemical kinetics, energy balance with a separate electron temperature, multifluid hydrodynamics with a transition to free molecular flow, fast-streaming atomic and molecular hydrogen, counter and cross streaming of the ionized species relative to the neutral species in the coma-solar wind interaction region with momentum exchange by elastic collisions, mass-loading through ion pick-up, and Lorentz forces of the advected magnetic field. The results, both inside and outside of the contact surface, are discussed and compared with the relevant HIS ion mass spectra.

  17. Nuclear chemistry progress report

    SciTech Connect

    Viola, V.E.; Kwiatkowski, K.

    1993-08-01

    This is the annual progress report for the Indiana University nuclear chemistry program for the 1992/1993 year. Accomplishments include the construction, testing, and initial experimental runs of the Indiana Silicon Sphere (ISiS) 4{pi} charged particle detector. ISiS is designed to study energy dissipation and multifragmentation phenomena in light-ion-induced nuclear reactions at medium-to-high energies. Its second test run was to examine 3.6 GeV {sup 3}He beam reactions at Laboratoire National Saturne (LNS) in Saclay. The development and deployment of this system has occupied a great deal of the groups effort this reporting period. Additional work includes: calculations of isotopic IMF yields in the {sup 4}He + {sup 116,124}Sn reaction; cross sections for A = 6 - 30 fragments from the {sup 4}He + {sup 28}Si reaction at 117 and 198 MeV; charging effects of passivated silicon detectors; neck emission of intermediate-mass fragments in the fission of hot heavy nuclei.

  18. Chemistry in one dimension.

    PubMed

    Loos, Pierre-François; Ball, Caleb J; Gill, Peter M W

    2015-02-07

    We report benchmark results for one-dimensional (1D) atomic and molecular systems interacting via the Coulomb operator |x|(-1). Using various wavefunction-type approaches, such as Hartree-Fock theory, second- and third-order Møller-Plesset perturbation theory and explicitly correlated calculations, we study the ground state of atoms with up to ten electrons as well as small diatomic and triatomic molecules containing up to two electrons. A detailed analysis of the 1D helium-like ions is given and the expression of the high-density correlation energy is reported. We report the total energies, ionization energies, electron affinities and other physical properties of the many-electron 1D atoms and, using these results, we construct the 1D analog of Mendeleev's periodic table. We find that the 1D periodic table contains only two groups: the alkali metals and the noble gases. We also calculate the dissociation curves of several 1D diatomics and study the chemical bond in H2(+), HeH(2+), He2(3+), H2, HeH(+) and He2(2+). We find that, unlike their 3D counterparts, 1D molecules are primarily bound by one-electron bonds. Finally, we study the chemistry of H3(+) and we discuss the stability of the 1D polymer resulting from an infinite chain of hydrogen atoms.

  19. Organic chemistry on Titan

    NASA Technical Reports Server (NTRS)

    Chang, S.; Scattergood, T.; Aronowitz, S.; Flores, J.

    1978-01-01

    Observations of nonequilibrium phenomena on the Saturn satellite Titan indicate the occurrence of organic chemical evolution. Greenhouse and thermal inversion models of Titan's atmosphere provide environmental constraints within which various pathways for organic chemical synthesis are assessed. Experimental results and theoretical modeling studies suggest that the organic chemistry of the satellite may be dominated by two atmospheric processes: energetic-particle bombardment and photochemistry. Reactions initiated in various levels of the atmosphere by cosmic ray, Saturn wind, and solar wind particle bombardment of a CH4 - N2 atmospheric mixture can account for the C2-hydrocarbons, the UV-visible-absorbing stratospheric haze, and the reddish color of the satellite. Photochemical reactions of CH4 can also account for the presence of C2-hydrocarbons. In the lower Titan atmosphere, photochemical processes will be important if surface temperatures are sufficiently high for gaseous NH3 to exist. Hot H-atom reactions initiated by photo-dissociation of NH3 can couple the chemical reactions of NH3 and CH4 and produce organic matter.

  20. ENVIRONMENTAL ANALYTICAL CHEMISTRY OF ...

    EPA Pesticide Factsheets

    Within the scope of a number of emerging contaminant issues in environmental analysis, one area that has received a great deal of public interest has been the assessment of the role of pharmaceuticals and personal care products (PPCPs) as stressors and agents of change in ecosystems as well as their role in unplanned human exposure. The relationship between personal actions and the occurrence of PPCPs in the environment is clear-cut and comprehensible to the public. In this overview, we attempt to examine the separations aspect of the analytical approach to the vast array of potential analytes among this class of compounds. We also highlight the relationship between these compounds and endocrine disrupting compounds (EDCs) and between PPCPs and EDCs and the more traditional environmental analytes such as the persistent organic pollutants (POPs). Although the spectrum of chemical behavior extends from hydrophobic to hydrophilic, the current focus has shifted to moderately and highly polar analytes. Thus, emphasis on HPLC and LC/MS has grown and MS/MS has become a detection technique of choice with either electrospray ionization or atmospheric pressure chemical ionization. This contrasts markedly with the bench mark approach of capillary GC, GC/MS and electron ionization in traditional environmental analysis. The expansion of the analyte list has fostered new vigor in the development of environmental analytical chemistry, modernized the range of tools appli

  1. Mars aqueous chemistry experiment

    NASA Technical Reports Server (NTRS)

    Clark, Benton C.; Mason, Larry W.

    1994-01-01

    Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. The second year of the MACE project has shown significant progress in two major areas. MACE Instrument concept definition is a baseline design that has been generated for the complete MACE instrument, including definition of analysis modes, mass estimates and thermal model. The design includes multiple reagent reservoirs, 10 discrete analysis cells, sample manipulation capability, and thermal control. The MACE Measurement subsystems development progress is reported regarding measurement capabilities for aqueous ion sensing, evolved gas sensing, solution conductivity measurement, reagent addition (titration) capabilities, and optical sensing of suspended particles.

  2. Plants and Medicinal Chemistry--2

    ERIC Educational Resources Information Center

    Bailey, D.

    1977-01-01

    Second of a two part article on the influence of plants on medicinal chemistry. This part considers how drugs work, the attempts to develop anaesthetics safer than cocaine, and useful poisons. (Author/SL)

  3. Organometallic Chemistry. Final Progress Report

    SciTech Connect

    2003-07-14

    The Gordon Research Conference (GRC) on Organometallic Chemistry was held at Salve Regina, Newport, Rhode Island, 7/21-26/02. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  4. Chemistry in the Justice System.

    ERIC Educational Resources Information Center

    Hazdra, James J.

    1980-01-01

    The application of chemistry to the justice system is presented. The role of the forensic chemist, historical development of forensic laboratories, and tools of the criminalists are also discussed. (HM)

  5. Beginning Chemistry Can Be Relevant

    ERIC Educational Resources Information Center

    Corwin, James F.

    1971-01-01

    Reviews ways of applying laboratory work in general and analytical chemistry to supermarket products. Describes ways water and air pollution analysis can illustrate acid-base reactions, redox reactions, precipitimetry, and colorimetry. (PR)

  6. QDB: Validated Plasma Chemistries Database

    NASA Astrophysics Data System (ADS)

    Rahimi, Sara; Hamilton, James; Hill, Christian; Tennyson, Jonathan; UCL Team

    2016-09-01

    One of most challenging recurring problems when modelling plasmas is the lack of data. This lack of complete and validated datasets hinders research on plasma processes and curbs development of industrial Applications. We will describe the QDB project which aims to fill this missing link by provide a platform for exchange and validation of chemistry datasets. The database will collate published data on both electron scattering and heavy particle reactions and also facilitates and encourages peer-to-peer data sharing by its users. This data platform is rigorously supported by the validation methodical validation of the datasetsan automated chemistry generator employed; this methodology identifies missing reactions in chemistries which although important are currently unreported in the literature and employs mathematical methods to analyze the importance of these chemistries. Gaps in the datasets are filled using in house theoretical methods.

  7. A Touch of Relevant Chemistry.

    ERIC Educational Resources Information Center

    Becker, Ernest I.

    1981-01-01

    Suggests using National Institute for Occupational Safety and Health (NIOSH) criteria documents as a source for special topics material in chemistry. Presents a list of selected NIOSH documents, ordering information, and reviews one document on formaldehyde in some detail. (SK)

  8. Organic Experiments for Introductory Chemistry.

    ERIC Educational Resources Information Center

    Rayner-Canham, Geoff

    1985-01-01

    Describes test-tube organic chemistry procedures (using comparatively safe reagents) for the beginning student. These procedures are used to: examine differences between saturated and unsaturated hydrocarbons; compare structural isomers; and compare organic and inorganic acids and bases. (DH)

  9. One century of aryne chemistry.

    PubMed

    Wenk, Hans Henning; Winkler, Michael; Sander, Wolfram

    2003-02-03

    Arynes, which are formally derived from aromatic rings by abstraction of two hydrogen atoms, have been a focus of organic chemistry for 100 years. In contrast to ortho-benzyne, which is mentioned in almost every introductory textbook on organic reaction mechanisms as a reactive intermediate of nucleophilic aromatic substitution, the meta and para isomers were regarded as rather exotic until recently. This situation has changed dramatically with the discovery of the enediyne antibiotics, a promising new class of antitumor drugs, and has aroused the interest of research groups from all branches of chemistry. Nowadays, arynes and related compounds are among the most intensively studied systems in chemistry. However, many aspects of the chemistry of these reactive intermediates are not well understood yet. In this review we outline the historical developement with an emphasis on recent progress in this challenging field of research.

  10. Part 7: Environmental Chemistry, Revised.

    ERIC Educational Resources Information Center

    Douville, Judith A.

    2003-01-01

    Discusses resources on applied/interdisciplinary areas of chemistry available as books and electronic materials that mostly target graduate students, faculty, and chemists in the industry. (Author/YDS)

  11. New Trends in Chemistry Teaching, Volume 2.

    ERIC Educational Resources Information Center

    Cartmell, E.

    This second volume of UNESCO's series on New Trends in Chemistry Teaching presents papers originally published during 1966 and 1967 in leading chemistry-teaching periodicals of the world. The papers have been grouped in sections - structure, energetics and kinetics, acids and bases, organic chemistry, electrochemistry, chemistry and industry,…

  12. The Place of Macromolecules in Freshman Chemistry

    ERIC Educational Resources Information Center

    Wunderlich, Bernhard

    1973-01-01

    Discusses the inclusion of knowledge on macromolecules into a freshman chemistry course which emphasizes topics in organic chemistry, polymer science and biochemistry, atoms, chemical thermodynamics, and inorganic chemistry. Indicates that the program is the only way to keep chemistry education up to date. (CC)

  13. 42 CFR 493.839 - Condition: Chemistry.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 5 2012-10-01 2012-10-01 false Condition: Chemistry. 493.839 Section 493.839... These Tests § 493.839 Condition: Chemistry. The specialty of chemistry includes for the purposes of proficiency testing the subspecialties of routine chemistry, endocrinology, and toxicology....

  14. 42 CFR 493.839 - Condition: Chemistry.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 5 2013-10-01 2013-10-01 false Condition: Chemistry. 493.839 Section 493.839... These Tests § 493.839 Condition: Chemistry. The specialty of chemistry includes for the purposes of proficiency testing the subspecialties of routine chemistry, endocrinology, and toxicology....

  15. 42 CFR 493.839 - Condition: Chemistry.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 5 2011-10-01 2011-10-01 false Condition: Chemistry. 493.839 Section 493.839... These Tests § 493.839 Condition: Chemistry. The specialty of chemistry includes for the purposes of proficiency testing the subspecialties of routine chemistry, endocrinology, and toxicology....

  16. 42 CFR 493.839 - Condition: Chemistry.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 5 2014-10-01 2014-10-01 false Condition: Chemistry. 493.839 Section 493.839... These Tests § 493.839 Condition: Chemistry. The specialty of chemistry includes for the purposes of proficiency testing the subspecialties of routine chemistry, endocrinology, and toxicology....

  17. 42 CFR 493.839 - Condition: Chemistry.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 5 2010-10-01 2010-10-01 false Condition: Chemistry. 493.839 Section 493.839... These Tests § 493.839 Condition: Chemistry. The specialty of chemistry includes for the purposes of proficiency testing the subspecialties of routine chemistry, endocrinology, and toxicology....

  18. Effective Chemistry Communication in Informal Environments

    ERIC Educational Resources Information Center

    National Academies Press, 2016

    2016-01-01

    Chemistry plays a critical role in daily life, impacting areas such as medicine and health, consumer products, energy production, the ecosystem, and many other areas. Communicating about chemistry in informal environments has the potential to raise public interest and understanding of chemistry around the world. However, the chemistry community…

  19. Peer Mentoring in the General Chemistry and Organic Chemistry Laboratories: The Pinacol Rearrangement--An Exercise in NMR and IR Spectroscopy for General Chemistry and Organic Chemistry Laboratories

    ERIC Educational Resources Information Center

    Arrington, Caleb A.; Hill, Jameica B.; Radfar, Ramin; Whisnant, David M.; Bass, Charles G.

    2008-01-01

    This article describes a discovery experiment for general chemistry and organic chemistry labs. Although the pinacol rearrangement has been employed in undergraduate organic laboratories before, in this application organic chemistry students act as mentors to students of general chemistry. Students work together using distillation--a new technique…

  20. Physical chemistry and the environment

    SciTech Connect

    Dunning, T.H. Jr.; Garrett, B.C.; Kolb, C.E. Jr.; Shaw, R.W.; Choppin, G.R.; Wagner, A.F.

    1994-08-01

    From the ozone hole and the greenhouse effect to plastics recycling and hazardous waste disposal, society faces a number of issues, the solutions to which require an unprecedented understanding of the properties of molecules. We are coming to realize that the environment is a coupled set of chemical systems, its dynamics determining the welfare of the biosphere and of humans in particular. These chemical systems are governed by fundamental molecular interactions, and they present chemists with an unparalleled challenge. The application of current concepts of molecular behavior and of up-to-date experimental and computational techniques can provide us with insights into the environment that are needed to mitigate past damage, to anticipate the impact of current human activity, and to avoid future insults to the environment. Environmental chemistry encompasses a number of separate, yet interlocking, areas of research. In all of these areas progress is limited by an inadequate understanding of the underlying chemical processes involved. Participation of all chemical approaches -- experimental, theoretical and computational -- and of all disciplines of chemistry -- organic, inorganic, physical, analytical and biochemistry -- will be required to provide the necessary fundamental understanding. The Symposium on ``Physical Chemistry and the Environment`` was designed to bring the many exciting and challenging physical chemistry problems involved in environmental chemistry to the attention of a larger segment of the physical chemistry community.

  1. Analytical Chemistry as an Information Science.

    DTIC Science & Technology

    1981-06-01

    AD-AIOS 433 WASHINGTON UNIV SEATTLE LAB OR CHEMOMETRICS /7/ ANALYTICAL CHEMISTRY AS AN INFORMATION SCIENCE Ul NAb7/ .JUN 81 B A KO WALSKI NUUUIA 75C...AN INFORMATION SCIENCE by B. R. Kowalski Prepared for Publication in Trends in Analytical Chemistry University of Washington Department of Chemistry...S. TYPE OF REPORT & PERIOD COVERED Technical Report - Interim ANALYTICAL CHEMISTRY AS AN INFORMATION SCIENCE , 2/1981 - 6/1981 6. PERFORMING ORG

  2. National Chemistry Week 2000: JCE Resources in Food Chemistry

    NASA Astrophysics Data System (ADS)

    Jacobsen, Erica K.

    2000-10-01

    November brings another National Chemistry Week, and this year's theme is food chemistry. I was asked to collect and evaluate JCE resources for use with this theme, a project that took me deep into past issues of JCE and yielded many treasures. Here we present the results of searches for food chemistry information and activities. While the selected articles are mainly at the high school and college levels, there are some excellent ones for the elementary school level and some that can be adapted for younger students. The focus of all articles is on the chemistry of food itself. Activities that only use food to demonstrate a principle other than food chemistry are not included. Articles that cover household products such as cleansers and pharmaceuticals are also not included. Each article has been characterized as a demonstration, experiment, calculation, activity, or informational item; several fit more than one classification. Also included are keywords and an evaluation as to which levels the article may serve.

  3. The Chemistry of Planet Formation

    NASA Astrophysics Data System (ADS)

    Oberg, Karin I.

    2017-01-01

    Exo-planets are common, and they span a large range of compositions. The origins of the observed diversity of planetary compositions is largely unconstrained, but must be linked to the planet formation physics and chemistry. Among planets that are Earth-like, a second question is how often such planets form hospitable to life. A fraction of exo-planets are observed to be ‘physically habitable’, i.e. of the right temperature and bulk composition to sustain a water-based prebiotic chemistry, but this does not automatically imply that they are rich in the building blocks of life, in organic molecules of different sizes and kinds, i.e. that they are chemically habitable. In this talk I will argue that characterizing the chemistry of protoplanetary disks, the formation sites of planets, is key to address both the origins of planetary bulk compositions and the likelihood of finding organic matter on planets. The most direct path to constrain the chemistry in disks is to directly observe it. In the age of ALMA it is for the first time possible to image the chemistry of planet formation, to determine locations of disk snowlines, and to map the distributions of different organic molecules. Recent ALMA highlights include constraints on CO snowline locations, the discovery of spectacular chemical ring systems, and first detections of more complex organic molecules. Observations can only provide chemical snapshots, however, and even ALMA is blind to the majority of the chemistry that shapes planet formation. To interpret observations and address the full chemical complexity in disks requires models, both toy models and astrochemical simulations. These models in turn must be informed by laboratory experiments, some of which will be shown in this talk. It is thus only when we combine observational, theoretical and experimental constraints that we can hope to characterize the chemistry of disks, and further, the chemical compositions of nascent planets.

  4. Medicinal electrochemistry: integration of electrochemistry, medicinal chemistry and computational chemistry.

    PubMed

    Almeida, M O; Maltarollo, V G; de Toledo, R A; Shim, H; Santos, M C; Honorio, K M

    2014-01-01

    Over the last centuries, there were many important discoveries in medicine that were crucial for gaining a better understanding of several physiological processes. Molecular modelling techniques are powerful tools that have been successfully used to analyse and interface medicinal chemistry studies with electrochemical experimental results. This special combination can help to comprehend medicinal chemistry problems, such as predicting biological activity and understanding drug action mechanisms. Electrochemistry has provided better comprehension of biological reactions and, as a result of many technological improvements, the combination of electrochemical techniques and biosensors has become an appealing choice for pharmaceutical and biomedical analyses. Therefore, this review will briefly outline the present scope and future advances related to the integration of electrochemical and medicinal chemistry approaches based on various applications from recent studies.

  5. Cycloadditions in modern polymer chemistry.

    PubMed

    Delaittre, Guillaume; Guimard, Nathalie K; Barner-Kowollik, Christopher

    2015-05-19

    Synthetic polymer chemistry has undergone two major developments in the last two decades. About 20 years ago, reversible-deactivation radical polymerization processes started to give access to a wide range of polymeric architectures made from an almost infinite reservoir of functional building blocks. A few years later, the concept of click chemistry revolutionized the way polymer chemists approached synthetic routes. Among the few reactions that could qualify as click, the copper-catalyzed azide-alkyne cycloaddition (CuAAC) initially stood out. Soon, many old and new reactions, including cycloadditions, would further enrich the synthetic macromolecular chemistry toolbox. Whether click or not, cycloadditions are in any case powerful tools for designing polymeric materials in a modular fashion, with a high level of functionality and, sometimes, responsiveness. Here, we wish to describe cycloaddition methodologies that have been reported in the last 10 years in the context of macromolecular engineering, with a focus on those developed in our laboratories. The overarching structure of this Account is based on the three most commonly encountered cycloaddition subclasses in organic and macromolecular chemistry: 1,3-dipolar cycloadditions, (hetero-)Diels-Alder cycloadditions ((H)DAC), and [2+2] cycloadditions. Our goal is to briefly describe the relevant reaction conditions, the advantages and disadvantages, and the realized polymer applications. Furthermore, the orthogonality of most of these reactions is highlighted because it has proven highly beneficial for generating unique, multifunctional polymers in a one-pot reaction. The overview on 1,3-dipolar cycloadditions is mostly centered on the application of CuAAC as the most travelled route, by far. Besides illustrating the capacity of CuAAC to generate complex polymeric architectures, alternative 1,3-dipolar cycloadditions operating without the need for a catalyst are described. In the area of (H)DA cycloadditions

  6. Teaching Chemistry in the New Century: Inorganic Chemistry

    NASA Astrophysics Data System (ADS)

    Dorhout, Peter K.

    2001-09-01

    At the San Diego ACS meeting, members of the academic community came together to share their visions for teaching inorganic chemistry. They discussed new laboratory experiences, virtual textbooks, integration of computers in the laboratory, undergraduate research experiences, and new ways of classifying reactions to enable students to recognize and categorize reaction types. It was clear from the presentations that, while the toolbox of the inorganic chemist is not now as sophisticated as the organic chemist's, that toolbox must evolve (and is evolving) if we are to understand just a fraction of the unique chemistry that is inorganic.

  7. Towards Bildung-Oriented Chemistry Education

    NASA Astrophysics Data System (ADS)

    Sjöström, Jesper

    2013-07-01

    This paper concerns Bildung-oriented chemistry education, based on a reflective and critical discourse of chemistry. It is contrasted with the dominant type of chemistry education, based on the mainstream discourse of chemistry. Bildung-oriented chemistry education includes not only content knowledge in chemistry, but also knowledge about chemistry, both about the nature of chemistry and about its role in society. In 2004 Mahaffy suggested a tetrahedron model based on Johnstone's chemical triangle. The latter represents the formal aspects of chemistry teaching (macro, submicro, and symbolic) and the top of the tetrahedron represents a human element. In the present paper the following subdivision of the top is suggested (starting from the bottom): (1) applied chemistry, (2) socio-cultural context, and (3) critical-philosophic approach. The professional identity of the Bildung-oriented chemistry teacher differs from that of the chemist and is informed by research fields such as Philosophy of Chemistry, Science and Technology Studies, and Environmental Education. He/she takes a socio-critical approach to chemistry, emphasising both the benefits and risks of chemistry and its applications.

  8. Atmospheric Chemistry and Air Pollution

    DOE PAGES

    Gaffney, Jeffrey S.; Marley, Nancy A.

    2003-01-01

    Atmospheric chemistry is an important discipline for understanding air pollution and its impacts. This mini-review gives a brief history of air pollution and presents an overview of some of the basic photochemistry involved in the production of ozone and other oxidants in the atmosphere. Urban air quality issues are reviewed with a specific focus on ozone and other oxidants, primary and secondary aerosols, alternative fuels, and the potential for chlorine releases to amplify oxidant chemistry in industrial areas. Regional air pollution issues such as acid rain, long-range transport of aerosols and visibility loss, and the connections of aerosols to ozonemore » and peroxyacetyl nitrate chemistry are examined. Finally, the potential impacts of air pollutants on the global-scale radiative balances of gases and aerosols are discussed briefly.« less

  9. Atmospheric chemistry and air pollution.

    PubMed

    Gaffney, Jeffrey S; Marley, Nancy A

    2003-04-07

    Atmospheric chemistry is an important discipline for understanding air pollution and its impacts. This mini-review gives a brief history of air pollution and presents an overview of some of the basic photochemistry involved in the production of ozone and other oxidants in the atmosphere. Urban air quality issues are reviewed with a specific focus on ozone and other oxidants, primary and secondary aerosols, alternative fuels, and the potential for chlorine releases to amplify oxidant chemistry in industrial areas. Regional air pollution issues such as acid rain, long-range transport of aerosols and visibility loss, and the connections of aerosols to ozone and peroxyacetyl nitrate chemistry are examined. Finally, the potential impacts of air pollutants on the global-scale radiative balances of gases and aerosols are discussed briefly.

  10. Surface chemistries for antibody microarrays

    SciTech Connect

    Seurynck-Servoss, Shannon L.; Baird, Cheryl L.; Rodland, Karin D.; Zangar, Richard C.

    2007-05-01

    Enzyme-linked immunosorbent assay (ELISA) microarrays promise to be a powerful tool for the detection of disease biomarkers. The original technology for printing ELISA microarray chips and capturing antibodies on slides was derived from the DNA microarray field. However, due to the need to maintain antibody structure and function when immobilized, surface chemistries used for DNA microarrays are not always appropriate for ELISA microarrays. In order to identify better surface chemistries for antibody capture, a number of commercial companies and academic research groups have developed new slide types that could improve antibody function in microarray applications. In this review we compare and contrast the commercially available slide chemistries, as well as highlight some promising recent advances in the field.

  11. Understanding MAOS through computational chemistry.

    PubMed

    Prieto, P; de la Hoz, A; Díaz-Ortiz, A; Rodríguez, A M

    2017-01-23

    The importance of microwave irradiation in organic synthesis today is unquestionable, but in many cases the nature of these improvements remains unknown. Exploiting the benefits that microwave irradiation has in chemistry is still hindered by a lack of understanding of the physical principles of the interaction of microwave irradiation with the components of a reaction. Moreover, dielectric properties vary with temperature and along the reaction coordinate and this makes the situation more complex. Experimental determinations employed to date in Microwave-Assisted Organic Chemistry (MAOS) are characterized by the importance of thermal heating. In this way the separation of thermal heating from any other effect of electromagnetic radiation is completely impossible. This review provides an overview of the use of Computational Chemistry in MAOS to provide a theoretical understanding of the factors that can be used to explain the improvements in MAOS and how computational calculations can be used as a predictive tool.

  12. Mass spectrometry. [in organic chemistry

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Shackleton, C. H. L.; Howe, I.; Chizhov, O. S.

    1978-01-01

    A review of mass spectrometry in organic chemistry is given, dealing with advances in instrumentation and computer techniques, selected topics in gas-phase ion chemistry, and applications in such fields as biomedicine, natural-product studies, and environmental pollution analysis. Innovative techniques and instrumentation are discussed, along with chromatographic-mass spectrometric on-line computer techniques, mass spectral interpretation and management techniques, and such topics in gas-phase ion chemistry as electron-impact ionization and decomposition, photoionization, field ionization and desorption, high-pressure mass spectrometry, ion cyclotron resonance, and isomerization reactions of organic ions. Applications of mass spectrometry are examined with respect to bio-oligomers and their constituents, biomedically important substances, microbiology, environmental organic analysis, and organic geochemistry.

  13. 1997 Atmospheric Chemistry Colloquium for Emerging Senior Scientists

    SciTech Connect

    Paul H. Wine

    1998-11-23

    DOE's Atmospheric Chemistry Program is providing partial funding for the Atmospheric Chemistry Colloquium for Emerging Senior Scientists (ACCESS) and FY 1997 Gordon Research Conference in Atmospheric Chemistry

  14. An update on chemistry analyzers.

    PubMed

    Vap, L M; Mitzner, B

    1996-09-01

    This update of six chemistry analyzers available to the clinician discusses several points that should be considered prior to the purchase of equipment. General topics include how to best match an instrument to clinic needs and the indirect costs associated with instrument operation. Quality assurance recommendations are discussed and common terms are defined. Specific instrument features, principles of operation, performance, and costs are presented. The information provided offers potential purchasers an objective approach to the evaluation of a chemistry analyzer for the veterinary clinic.

  15. A Wet Chemistry Laboratory Cell

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This picture of NASA's Phoenix Mars Lander's Wet Chemistry Laboratory (WCL) cell is labeled with components responsible for mixing Martian soil with water from Earth, adding chemicals and measuring the solution chemistry. WCL is part of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument suite on board the Phoenix lander.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  16. The chemistry of graphene oxide.

    PubMed

    Dreyer, Daniel R; Park, Sungjin; Bielawski, Christopher W; Ruoff, Rodney S

    2010-01-01

    The chemistry of graphene oxide is discussed in this critical review. Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure. Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene-like materials, is also discussed. This review will be of value to synthetic chemists interested in this emerging field of materials science, as well as those investigating applications of graphene who would find a more thorough treatment of the chemistry of graphene oxide useful in understanding the scope and limitations of current approaches which utilize this material (91 references).

  17. Actinide chemistry in ionic liquids.

    PubMed

    Takao, Koichiro; Bell, Thomas James; Ikeda, Yasuhisa

    2013-04-01

    This Forum Article provides an overview of the reported studies on the actinide chemistry in ionic liquids (ILs) with a particular focus on several fundamental chemical aspects: (i) complex formation, (ii) electrochemistry, and (iii) extraction behavior. The majority of investigations have been dedicated to uranium, especially for the 6+ oxidation state (UO2(2+)), because the chemistry of uranium in ordinary solvents has been well investigated and uranium is the most abundant element in the actual nuclear fuel cycles. Other actinides such as thorium, neptunium, plutonium, americium, and curiumm, although less studied, are also of importance in fully understanding the nuclear fuel engineering process and the safe geological disposal of radioactive wastes.

  18. Perspectives on Computational Organic Chemistry

    PubMed Central

    Streitwieser, Andrew

    2009-01-01

    The author reviews how his early love for theoretical organic chemistry led to experimental research and the extended search for quantitative correlations between experiment and quantum calculations. The experimental work led to ion pair acidities of alkali-organic compounds and most recently to equilibria and reactions of lithium and cesium enolates in THF. This chemistry is now being modeled by ab initio calculations. An important consideration is the treatment of solvation in which coordination of the alkali cation with the ether solvent plays a major role. PMID:19518150

  19. Sustainable Chemistry at Sungkyunkwan University.

    PubMed

    Park, Nam-Gyu

    2015-07-20

    Special Issue: Sustainable Chemistry at Sungkyunkwan University. Sustainable chemistry is key to the development of efficient renewable energies, which will become more and more important in order to combat global warming. In this Editorial, guest editor Prof. Nam-Gyu Park describes the context of this Special Issue on top-quality research towards sustainability performed at Sungkyunkwan University (SKKU) in Korea. Scientists at SKKU work on, for example, photovoltaic solar cells to generate low-cost electricity, lithium batteries and capacitors to store electricity, piezoelectric nanogenerators, thermoelectric devices, hydrogen generation, and fuel cells.

  20. Molten fluoride fuel salt chemistry

    SciTech Connect

    Toth, L.M.; Del Cul, G.D.; Dai, S.; Metcalf, D.H.

    1994-09-01

    The chemistry of molten fluorides is traced from their development as fuels in the Molten Salt Reactor Experiment with important factors in their selection being discussed. Key chemical characteristics such as solubility, redox behavior, and chemical activity are explained as they relate to the behavior of molten fluoride fuel systems. Fission product behavior is described along with processing experience. Development requirements for fitting the current state of the chemistry to modern nuclear fuel system are described. It is concluded that while much is known about molten fluoride behavior, processing and recycle of the fuel components is a necessary factor if future systems are to be established.

  1. Knot theory in modern chemistry.

    PubMed

    Horner, Kate E; Miller, Mark A; Steed, Jonathan W; Sutcliffe, Paul M

    2016-11-21

    Knot theory is a branch of pure mathematics, but it is increasingly being applied in a variety of sciences. Knots appear in chemistry, not only in synthetic molecular design, but also in an array of materials and media, including some not traditionally associated with knots. Mathematics and chemistry can now be used synergistically to identify, characterise and create knots, as well as to understand and predict their physical properties. This tutorial review provides a brief introduction to the mathematics of knots and related topological concepts in the context of the chemical sciences. We then survey the broad range of applications of the theory to contemporary research in the field.

  2. Integrating Computational Chemistry into the Physical Chemistry Curriculum

    ERIC Educational Resources Information Center

    Johnson, Lewis E.; Engel, Thomas

    2011-01-01

    Relatively few undergraduate physical chemistry programs integrate molecular modeling into their quantum mechanics curriculum owing to concerns about limited access to computational facilities, the cost of software, and concerns about increasing the course material. However, modeling exercises can be integrated into an undergraduate course at a…

  3. General Chemistry Students' Goals for Chemistry Laboratory Coursework

    ERIC Educational Resources Information Center

    DeKorver, Brittland K.; Towns, Marcy H.

    2015-01-01

    Little research exists on college students' learning goals in chemistry, let alone specifically pertaining to laboratory coursework. Because students' learning goals are linked to achievement and dependent on context, research on students' goals in the laboratory context may lead to better understanding about the efficacy of lab curricula. This…

  4. Integrating Particulate Representations into AP Chemistry and Introductory Chemistry Courses

    ERIC Educational Resources Information Center

    Prilliman, Stephen G.

    2014-01-01

    The College Board's recently revised curriculum for advanced placement (AP) chemistry places a strong emphasis on conceptual understanding, including representations of particle phenomena. This change in emphasis is informed by years of research showing that students could perform algorithmic calculations but not explain those calculations…

  5. Comparing Carbonyl Chemistry in Comprehensive Introductory Organic Chemistry Textbooks

    ERIC Educational Resources Information Center

    Nelson, Donna J.; Kumar, Ravi; Ramasamy, Saravanan

    2015-01-01

    Learning the chemistry of compounds containing carbonyl groups is difficult for undergraduate students partly because of a convolution of multiple possible reaction sites, competitive reactions taking place at those sites, different criteria needed to discern between the mechanisms of these reactions, and no straightforward selection method…

  6. Chemistry on the Go: Review of Chemistry Apps on Smartphones

    ERIC Educational Resources Information Center

    Libman, Diana; Huang, Ling

    2013-01-01

    touch-controlled computers such as smartphones and iPods are seeing dramatic growth with increasing adoption rates. This review covers about 30 popular and mostly free apps that can be used to learn chemistry and to serve as reference or research tools. The target…

  7. Chemistry for Artists and Art Buffs.

    ERIC Educational Resources Information Center

    Denio, Allen A.

    1979-01-01

    This course provides an attractive introduction to chemistry for a group of students who would normally avoid traditional chemistry courses. Topics include color, pigments, metals, ceramics, glass, paints, plastics, fibers, and dyes. (BB)

  8. Environmental Chemistry in the High School Curriculum.

    ERIC Educational Resources Information Center

    Stearns, Carole

    1988-01-01

    Discusses the incorporation of environmental chemistry topics into the traditional high school chemistry curriculum. Describes and provides lesson plans for the sulfur cycle and acid rain, and radioactivity and nuclear energy. Considers possible laboratory experiments. (CW)

  9. Outlook Bright for Computers in Chemistry.

    ERIC Educational Resources Information Center

    Baum, Rudy M.

    1981-01-01

    Discusses the recent decision to close down the National Resource for Computation in Chemistry (NRCC), implications of that decision, and various alternatives in the field of computational chemistry. (CS)

  10. Some Exercises Reflecting Green Chemistry Concepts

    ERIC Educational Resources Information Center

    Song, Yu-Min; Wang, Yong-Cheng; Geng, Zhi-Yuan

    2004-01-01

    Some exercises to introduce students to the concept of green chemistry are given. By doing these exercises, students develop an appreciation for the role of green chemistry on feedstock substitution, milder reaction conditions, reduced environmental exposure, and resource conservation.

  11. Process chemistry {ampersand} statistics quality assurance plan

    SciTech Connect

    Meznarich, H.K.

    1996-08-01

    This document provides quality assurance guidelines and quality control requirements for Process Chemistry and Statistics. This document is designed on the basis of Hanford Analytical Services Quality Assurance Plan (HASQAP) technical guidelines and is used for governing process chemistry activities.

  12. Halogen Chemistry in the CMAQ Model

    EPA Science Inventory

    Halogens (iodine and bromine) emitted from oceans alter atmospheric chemistry and influence atmospheric ozone mixing ratio. We previously incorporated a representation of detailed halogen chemistry and emissions of organic and inorganic halogen species into the hemispheric Commun...

  13. EVALUATING THE SUSTAINABILITY OF GREEN CHEMISTRIES

    EPA Science Inventory

    The U.S. EPA's National Risk Management Research Laboratory is developing a methodology for the evaluation of reaction chemistries. This methodology, called GREENSCOPE (Gauging Reaction Effectiveness for the ENvironmental Sustainability of Chemistries with a multi-Objective Proc...

  14. 40 CFR 721.3437 - Dialkyl ether.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... uses are: (i) Release to water. Requirements as specified in § 721.90 (a)(4), (b)(4), and (c)(4) (where N = 180 ppb). (ii) (b) Specific requirements. The provisions of subpart A of this part apply to this section except as modified by this paragraph. (1) Recordkeeping requirements. Recordkeeping...

  15. Enzyme activity in dialkyl phosphate ionic liquids

    SciTech Connect

    Thomas, M.F.; Dunn, J.; Li, L.-L.; Handley-Pendleton, J. M.; van der lelie, D.; Wishart, J. F.

    2011-12-01

    The activity of four metagenomic enzymes and an enzyme cloned from the straw mushroom, Volvariellavolvacea were studied in the following ionic liquids, 1,3-dimethylimidazolium dimethyl phosphate, [mmim][dmp], 1-ethyl-3-methylimidazolium dimethyl phosphate, [emim][dmp], 1-ethyl-3-methylimidazolium diethyl phosphate, [emim][dep] and 1-ethyl-3-methylimidazolium acetate, [emim][OAc]. Activity was determined by analyzing the hydrolysis of para-nitrobenzene carbohydrate derivatives. In general, the enzymes were most active in the dimethyl phosphate ionic liquids, followed by acetate. Generally speaking, activity decreased sharply for concentrations of [emim][dep] above 10% v/v, while the other ionic liquids showed less impact on activity up to 20% v/v.

  16. Ullmann's Encyclopedia of Industrial Chemistry.

    ERIC Educational Resources Information Center

    Chadwick, Sharon S.

    1988-01-01

    This review compares "Ullmann's Encyclopedia of Industrial Chemistry" with the "Kirk-Othmer Encyclopedia of Chemical Technology," two prominent encyclopedias of chemical technology and industry. Cost, quantity of information, organization, illustrations, authorship, abbreviations, online availability, and content of articles are discussed. (MES)

  17. Teaching Triple Science: GCSE Chemistry

    ERIC Educational Resources Information Center

    Learning and Skills Network (NJ3), 2007

    2007-01-01

    The Department for Children, Schools and Families (DCSF) has contracted with the Learning and Skills Network to support awareness and take-up of Triple Science GCSEs through the Triple Science Support Programme. This publication provides an introduction to teaching and learning approaches for the extension topics within GCSE Chemistry. It…

  18. Superheavy element chemistry at GARIS

    NASA Astrophysics Data System (ADS)

    Haba, Hiromitsu

    2016-12-01

    A gas-jet transport system has been installed to the RIKEN GAs-filled Recoil Ion Separator, GARIS to start up SuperHeavy Element (SHE) chemistry. This system is a promising approach for exploring new frontiers in SHE chemistry: background radioactivities from unwanted by-products are suppressed, a high gas-jet transport yield is achieved, and new chemical reactions can be investigated. Useful radioisotopes of 261Rfa,b, 262Db, and 265Sga,b for chemical studies were produced in the reactions of 248Cm(18O,5n)261Rfa,b, 248Cm(19F,5n)262Db, and 248Cm(22Ne,5n)265Sga,b, respectively. They were successfully extracted to a chemistry laboratory by the gas-jet method. Production and decay properties of 261Rfa,b, 262Db, and 265Sga,b were investigated in detail with the rotating wheel apparatus for α- and spontaneous fission spectrometry. Present status and perspectives of the SHE chemistry at GARIS are also briefly presented.

  19. Astronomy Matters for Chemistry Teachers.

    ERIC Educational Resources Information Center

    Huebner, Jay S.; And Others

    1996-01-01

    Describes basic misconceptions about the origin of elements and forms of matter found in chemistry texts that need modification in light of modern observational data and interpretations given in astronomy. Notes that there are forms of matter other than elements and compounds. Confounding examples from astronomy include white dwarfs, neutron…

  20. Synthesis: Click chemistry gets reversible

    NASA Astrophysics Data System (ADS)

    Fulton, David A.

    2016-10-01

    'Click' chemistry allows for the linking together of chemical modules, however, there are currently no methods that also allow for facile 'declicking' to unlink them. Now, a method has been developed to click together amines and thiols, and then allow a chemically triggered declick reaction to release the original molecular components.

  1. A Comprehensive General Chemistry Demonstration

    ERIC Educational Resources Information Center

    Sweeder, Ryan D.; Jeffery, Kathleen A.

    2013-01-01

    This article describes the use of a comprehensive demonstration suitable for a high school or first-year undergraduate introductory chemistry class. The demonstration involves placing a burning candle in a container adjacent to a beaker containing a basic solution with indicator. After adding a lid, the candle will extinguish and the produced…

  2. NSF Begins Chemistry Funding Experiment.

    ERIC Educational Resources Information Center

    Long, Janice R.

    1979-01-01

    The National Science Foundation's chemistry division has begun a year-long experiment to determine if the paperwork and red tape involved in research grants can be reduced, while at the same time increasing accountability for how the money is spent. (Author/BB)

  3. Laser ablation in analytical chemistry.

    PubMed

    Russo, Richard E; Mao, Xianglei; Gonzalez, Jhanis J; Zorba, Vassilia; Yoo, Jong

    2013-07-02

    In 2002, we wrote an Analytical Chemistry feature article describing the Physics of Laser Ablation in Microchemical Analysis. In line with the theme of the 2002 article, this manuscript discusses current issues in fundamental research, applications based on detecting photons at the ablation site (LIBS and LAMIS) and by collecting particles for excitation in a secondary source (ICP), and directions for the technology.

  4. Teaching Techniques in Clinical Chemistry.

    ERIC Educational Resources Information Center

    Wilson, Diane

    This master's thesis presents several instructional methods and techniques developed for each of eleven topics or subject areas in clinical chemistry: carbohydrate metabolism, lipid metabolism, diagnostic enzymology, endocrinology, toxicology, quality control, electrolytes, acid base balance, hepatic function, nonprotein nitrogenous compounds, and…

  5. Green chemistry for chemical synthesis

    PubMed Central

    Li, Chao-Jun; Trost, Barry M.

    2008-01-01

    Green chemistry for chemical synthesis addresses our future challenges in working with chemical processes and products by inventing novel reactions that can maximize the desired products and minimize by-products, designing new synthetic schemes and apparati that can simplify operations in chemical productions, and seeking greener solvents that are inherently environmentally and ecologically benign. PMID:18768813

  6. Radiation Chemistry in Organized Assemblies.

    ERIC Educational Resources Information Center

    Thomas, J. K.; Chen, T. S.

    1981-01-01

    Expands the basic concepts regarding the radiation chemistry of simple aqueous systems to more complex, but well defined, organized assemblies. Discusses the differences in behavior in comparison to simple systems. Reviews these techniques: pulse radiolysis, laser flash, photolysis, and steady state irradiation by gamma rays or light. (CS)

  7. An Introduction to Air Chemistry.

    ERIC Educational Resources Information Center

    Butcher, Samuel S.; Charlson, Robert J.

    Designed for those with no previous experience in the field, this book synthesizes the areas of chemistry and meteorology required to bring into focus some of the complex problems associated with the atmospheric environment. Subject matter moves from a review of the relevant chemical and meteorological principles to a discussion of the general…

  8. Organometallic chemistry: A new metathesis

    NASA Astrophysics Data System (ADS)

    Hennessy, Elisabeth T.; Jacobsen, Eric N.

    2016-08-01

    Carbonyls and alkenes, two of the most common functional groups in organic chemistry, generally do not react with one another. Now, a simple Lewis acid has been shown to catalyse metathesis between alkenes and ketones in a new carbonyl olefination reaction.

  9. The Chemistry of Color Photography

    ERIC Educational Resources Information Center

    Guida, Wayne C.; Raber, Douglas J.

    1975-01-01

    Presents several topics in color photography which can serve as an introduction of scientific concepts into the classroom, such as: photochemistry (energy transport), organic chemistry (dye formation), physics (nature of light), psychology (color perception), and engineering (isolation of different chemical processes within layers of the film).…

  10. Atmospheric chemistry over southern Africa

    NASA Astrophysics Data System (ADS)

    Gatebe, Charles K.; Levy, Robert C.; Thompson, Anne M.

    2012-03-01

    Changing Chemistry in a Changing Climate: Human and Natural Impacts Over Southern Africa (C4-SAR); Midrand, South Africa, 31 May to 3 June 2011 During the southern African dry season, regional haze from mixed industrial pollution, biomass burning aerosol and gases from domestic and grassland fires, and biogenic sources from plants and soils is worsened by a semipermanent atmospheric gyre over the subcontinent. These factors were a driver of several major international field campaigns in the 1990s and early 2000s and attracted many scientists to the region. Some researchers were interested in understanding fundamental processes governing chemistry of the atmosphere and interaction with climate change. Others found favorable conditions for evaluating satellite- derived measurements of atmospheric properties and a changing land surface. With that background in mind a workshop on atmospheric chemistry was held in South Africa. Sponsored by the International Commission on Atmospheric Chemistry and Global Pollution (ICACGP; http://www.icacgp.org/), the workshop received generous support from Eskom, the South African power utility; and the Climatology Research Group of the University of the Witwatersrand, Johannesburg, South Africa.

  11. Chemistry of the Burning Surface

    DTIC Science & Technology

    1993-10-12

    control voltage of the Pt filament is highly terial. This chemistry cannot be extracted by slowly heat- sensitive to the thermochemistry of the thin...azines. the residues formed at teach iernperature ’)ascd ýucli as melon, arc known to be thcriaalLv -.) tile absorhanice value ot ouhgaseous prod

  12. Thirty years through vanadium chemistry.

    PubMed

    Costa Pessoa, J

    2015-06-01

    The relevance of vanadium in biological systems is known for many years and vanadium-based catalysts have important industrial applications, however, till the beginning of the 80s research on vanadium chemistry and biochemistry did not receive much attention from the scientific community. The understanding of the broad bioinorganic implications resulting from the similarities between phosphate and vanadate(V) and the discovery of vanadium dependent enzymes gave rise to an enormous increase in interest in the chemistry and biological relevance of vanadium. Thereupon the last 30years corresponded to a period of enormous research effort in these fields, as well as in medicinal applications of vanadium and in the development of catalysts for use in fine-chemical synthesis, some of these inspired by enzymatic active sites. Since the 80s my group in collaboration with others made contributions, described throughout this text, namely in the understanding of the speciation of vanadium compounds in aqueous solution and in biological fluids, and to the transport of vanadium compounds in blood plasma and their uptake by cells. Several new types of vanadium compounds were also synthesized and characterized, with applications either as prospective therapeutic drugs or as homogeneous or heterogenized catalysts for the production of fine chemicals. The developments made are described also considering the international context of the evolution of the knowledge in the chemistry and bioinorganic chemistry of vanadium compounds during the last 30years. This article was compiled based on the Vanadis Award presentation at the 9th International Vanadium Symposium.

  13. Chemistry Teaching: Science or Alchemy?

    ERIC Educational Resources Information Center

    Johnstone, A. H.

    1997-01-01

    Suggests that the development of good chemistry teaching and the pursuit of research have essentially the same structure. Similarities include the need for a clear focus, efficiency in time and effort, and a direction that is more often right than wrong. (DDR)

  14. The Chemistry of the Planets.

    ERIC Educational Resources Information Center

    Blake, Peter

    1988-01-01

    Introduces knowledge of planetary chemistry for possible use in teaching. Discusses the chemical composition of the planets; the atmosphere and clouds of Venus, Jupiter and its moons, and Titan. Includes diagrams of the greenhouse effects in the solar system, elemental abundances, and the chemical composition of Jupiter. (RT)

  15. Chemistry without borders: An overview

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As chemistry becomes more globalized, it is important for an organization to be interconnected and adaptable, and for an individual to keep up with changes and latest scientific findings and keep options open. Many of the challenges and the opportunities of globalization are in the areas of jobs, re...

  16. General Chemistry for Waste Handlers.

    ERIC Educational Resources Information Center

    Sixtus, Michael E.

    This manual is intended for use in presenting a course which provides the content-specific general chemistry education required for the safety awareness and job enhancement of persons employed as waste handlers. The course, which was designed to be delivered to technicians at job sites in a lecture/demonstration format with several hands-on…

  17. Analytical Chemistry and the Microchip.

    ERIC Educational Resources Information Center

    Lowry, Robert K.

    1986-01-01

    Analytical techniques used at various points in making microchips are described. They include: Fourier transform infrared spectrometry (silicon purity); optical emission spectroscopy (quantitative thin-film composition); X-ray photoelectron spectroscopy (chemical changes in thin films); wet chemistry, instrumental analysis (process chemicals);…

  18. Textile Chemistry for the Artist.

    ERIC Educational Resources Information Center

    Butler, Sara; Malott, Sally

    1981-01-01

    Focuses on the chemistry of fibers commonly used by artists. Presents information regarding the reactions of these fibers to dyes, bleaches, solvents, and other selected agents of design. Tables provide a classification of natural and manufactured fibers, characteristics, chemical formulas and reactions of selected fibers, and characteristics of…

  19. Chemistry--The Big Picture

    ERIC Educational Resources Information Center

    Cassell, Anne

    2011-01-01

    Chemistry produces materials and releases energy by ionic or electronic rearrangements. Three structure types affect the ease with which a reaction occurs. In the Earth's crust, "solid crystals" change chemically only with extreme heat and pressure, unless their fixed ions touch moving fluids. On the other hand, in living things, "liquid crystals"…

  20. Botany, Chemistry, and Tropical Development.

    ERIC Educational Resources Information Center

    Headrick, Daniel R.

    1996-01-01

    Examines the role played by botany and chemistry in the development, exploitation, and later deterioration of tropical economies. Although near equals in 19th-century international trade, the development of synthetics by European scientists in the early 20th century crippled the tropical economies. Research, innovation, and investment protected…

  1. Individualizing Secondary School Chemistry Instruction

    ERIC Educational Resources Information Center

    Krockover, Gerald H.

    1971-01-01

    Discusses a study comparing the effectiveness of the group studies approach recommended in the teacher's guide for CBA chemistry with an individualized approach utilizing CBA materials. The individualized group did a well as or better than the other group. Reviews students' attitudes toward individualized course. Twenty-four references. (PR)

  2. Green Chemistry with Microwave Energy

    EPA Science Inventory

    Green chemistry utilizes a set of 12 principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture, and applications of chemical products (1). This newer chemical approach protects the environment by inventing safer and eco-friendl...

  3. Visualizing Chemistry: Investigations for Teachers.

    ERIC Educational Resources Information Center

    Ealy, Julie B.; Ealy, James L., Jr.

    This book contains 101 investigations for chemistry classrooms. Topics include: (1) Physical Properties; (2) Reactions of Some Elements; (3) Reactions Involving Gases; (4) Energy Changes; (5) Solutions and Solubility; (6) Transition Metals and Complex Ions; (7) Kinetics and Equilibrium; (8) Acids and Bases; (9) Oxidation-Reduction; (10)…

  4. Chemistry Curriculum Guide. Bulletin 1660.

    ERIC Educational Resources Information Center

    Louisiana State Dept. of Education, Baton Rouge. Div. of Academic Programs.

    This curriculum guide, developed to establish statewide curriculum standards for the Louisiana Competency-based Education Program, contains the minimum competencies and process skills that should be included in a chemistry course. It consists of: (1) a rationale for an effective science program; (2) a list and description of four major goals of…

  5. Text Editing in Chemistry Instruction.

    ERIC Educational Resources Information Center

    Ngu, Bing Hiong; Low, Renae; Sweller, John

    2002-01-01

    Describes experiments with Australian high school students that investigated differences in performance on chemistry word problems between two learning strategies: text editing, and conventional problem solving. Concluded that text editing had no advantage over problem solving in stoichiometry problems, and that the suitability of a text editing…

  6. Microcomputer Applications in Analytical Chemistry.

    ERIC Educational Resources Information Center

    Long, Joseph W.

    The first part of this paper addresses the following topics: (1) the usefulness of microcomputers; (2) applications for microcomputers in analytical chemistry; (3) costs; (4) major microcomputer systems and subsystems; and (5) which microcomputer to buy. Following these brief comments, the major focus of the paper is devoted to a discussion of…

  7. Computational Chemistry of Adhesive Bonds

    NASA Technical Reports Server (NTRS)

    Phillips, Donald H.

    1999-01-01

    This investigation is intended to determine the electrical mechanical, and chemical properties of adhesive bonds at the molecular level. The initial determinations will be followed by investigations of the effects of environmental effects on the chemistry and properties of the bond layer.

  8. Inquiry in the Chemistry Classroom

    ERIC Educational Resources Information Center

    Deters, Kelly

    2004-01-01

    In a survey of almost 600 high school chemistry teachers, it was found that almost half of them did not use inquiry in their classroom. For the survey, inquiry was defined as any lab in which students write the procedure themselves--the question/purpose/problem could be of the students' own design or provided for them. Many teachers indicated that…

  9. Chemistry Perfumes Your Daily Life

    ERIC Educational Resources Information Center

    Fortineau, Anne-Dominique

    2004-01-01

    A synopsis on the history of perfumery is presented, along with the various processes accessible for obtaining natural perfume constituents, and creation of synthetic chemicals. The important contribution of organic chemists in the invention of perfumes, aspects of fragrance chemistry, and general information on the perfume industry are…

  10. Contemporary Issues Related to Chemistry.

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 1981

    1981-01-01

    Summarizes papers presented at the Sixth Biennial Conference of Chemical Education in the areas of energy, recombinant DNA, public understanding of science, health and safety, inorganic chemistry, and environment. A bibliography of 21 presented papers in these areas is attached. (CS)

  11. Plasma chemistry and organic synthesis

    NASA Technical Reports Server (NTRS)

    Tezuka, M.

    1980-01-01

    The characteristic features of chemical reactions using low temperature plasmas are described and differentiated from those seen in other reaction systems. A number of examples of applications of plasma chemistry to synthetic reactions are mentioned. The production of amino acids by discharge reactions in hydrocarbon-ammonia-water systems is discussed, and its implications for the origins of life are mentioned.

  12. Organic chemistry in Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Scattergood, T.

    1982-01-01

    Laboratory photochemical simulations and other types of chemical simulations are discussed. The chemistry of methane, which is the major known constituent of Titan's atmosphere was examined with stress on what can be learned from photochemistry and particle irradiation. The composition of dust that comprises the haze layer was determined. Isotope fractionation in planetary atmospheres is also discussed.

  13. Recent developments in nitride chemistry

    SciTech Connect

    Niewa, R.; DiSalvo, F.J.

    1998-10-01

    The chemistry of ternary nitrides is reviewed with special focus on developments of the last two years (1996 and 1997). In particular, structures and properties of ternary and higher transition metal nitrides, main group nitrides, subnitrides, and nitride halides are compared, and a section on thermodynamics of ternary nitrides is included. Finally, methods for the preparation of gallium nitride single crystals are summarized.

  14. Distribution of archaeal and bacterial glycerol dialkyl glycerol tetraethers in tropical sediments from Guadeloupe (French West Indies): implications for application of the MBT/CBT and TEX86 proxies

    NASA Astrophysics Data System (ADS)

    Huguet, A.; Belmahdi, I.; Fosse, C.; Grossi, V.; Derenne, S.

    2012-04-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are lipids of high molecular weight present in membranes of Archaea and some bacteria. Archaeal membranes are composed predominantly of isoprenoid GDGTs, with acyclic or ring-containg biphytanyl chains. The amount of isoprenoid GDGTs with cyclopentyl moieties was shown to increase with water temperature and variations in surface water temperature can be determined via the TEX86 proxy. Recently, another type of GDGTs, with branched instead of isoprenoid alkyl chains, has been discovered in peat and was observed to occur ubiquitously in soils and in aquatic environments. Branched GDGTs were suggested to be produced in soils by still unknown bacteria. The degree of methylation of branched GDGTs, expressed in the MBT, was shown to depend on air temperature and to a lesser extent on soil pH, whereas the relative abundance of cyclopentyl rings of branched GDGTs, expressed in the CBT, was related to soil pH. The MBT/CBT proxies are increasingly used as paleoclimate proxies. The aim of this study was to investigate the distribution of GDGTs in tropical sediments from Guadeloupe (French West Indies). Surficial sediment samples were collected in four coastal water ponds: two located in Grande-Terre and two in a smaller island named La Désirade, 10 km east from Grande-Terre. GDGTs either present as core lipids (CLs; presumed of fossil origin) or derived from intact polar lipids (IPLs; markers for living cells) were analysed. A large part of archaeal GDGTs was present as IPLs (40-50% of total extractable archaeal GDGTs) in all sites. The proportion of IPL GDGTs of bacterial origin with respect to the total pool (CLs +IPLs) was 25-30% in the sediments from La Désirade and ~ 50% in the upper sediment layers from Grande-Terre. Interestingly, the distribution of archaeal and bacterial GDGTs differed between the four sites, as shown by the higher values of the TEX86 and MBT in sediments from La Désirade (TEX86~0.80; MBT~0

  15. Eleventh international symposium on radiopharmaceutical chemistry

    SciTech Connect

    1995-12-31

    This document contains abstracts of papers which were presented at the Eleventh International Symposium on Radiopharmaceutical Chemistry. Sessions included: radiopharmaceuticals for the dopaminergic system, strategies for the production and use of labelled reactive small molecules, radiopharmaceuticals for measuring metabolism, radiopharmaceuticals for the serotonin and sigma receptor systems, labelled probes for molecular biology applications, radiopharmaceuticals for receptor systems, radiopharmaceuticals utilizing coordination chemistry, radiolabelled antibodies, radiolabelling methods for small molecules, analytical techniques in radiopharmaceutical chemistry, and analytical techniques in radiopharmaceutical chemistry.

  16. Investigation of the configurational and conformational influences on the hormonal activity of 1,2-bis(2,6-dichloro-4-hydroxyphenyl)ethylenediamines and of their platinum(II) complexes. 1. Synthesis, estradiol receptor affinity, and estrogenic activity of diastereomeric [N-alkyl- and N,N'-dialkyl-1,2- bis(2,6-dichloro-4-hydroxyphenyl)ethylenediamine]dichloroplatinum(II) complexes.

    PubMed

    Gust, R; Niebler, K; Schönenberger, H

    1995-06-09

    N-Monoalkylated (Et) and N,N'-dialkylated (Me and Et) 1,2-bis(2,6-dichloro-4-hydroxyphenyl)-ethylenediamines and their dichloroplatinum(II) complexes were synthesized, and their configuration and conformational behavior were 1H-NMR spectroscopically clarified. The latter was brought in relation to their relative binding affinity (RBA) to the estrogen receptor as well as to their estrogenic potency. In contrast to the RR/SS-configurated diamines, the R/S-configurated ones showed marked estrogenic properties which correlate with the RBA's. In the related R/S-configurated complexes the estrogenic activity is determined by the same structural requirements as in the diamine series. However, a correlation between RBA's and estrogenic potencies is missing. The connection between spatial structure and activity is discussed by use of a drug-receptor model recently proposed by Höltje and Dall.

  17. DanceChemistry: Helping Students Visualize Chemistry Concepts through Dance Videos

    ERIC Educational Resources Information Center

    Tay, Gidget C.; Edwards, Kimberly D.

    2015-01-01

    A visual aid teaching tool, the DanceChemistry video series, has been developed to teach fundamental chemistry concepts through dance. These educational videos portray chemical interactions at the molecular level using dancers to represent chemical species. Students reported that the DanceChemistry videos helped them visualize chemistry ideas in a…

  18. The Philosophy of Chemistry as a New Resource for Chemistry Education

    ERIC Educational Resources Information Center

    Lombardi, Olimpia; Labarca, Martin

    2007-01-01

    The philosophy of chemistry has offered new tools that can guide educators in deciding how to balance descriptive and theoretical chemistry. The philosophy of chemistry has positive effects on the way that chemistry is taught and learned and it also leads educators to reach a better understanding of their own scientific discipline.

  19. Moving Chemistry Education into 3D: A Tetrahedral Metaphor for Understanding Chemistry

    ERIC Educational Resources Information Center

    Mahaffy, Peter

    2006-01-01

    A new conceptual metaphor is proposed to enrich the description of chemistry education and support the many existing efforts to help students make connections with the chemistry found in textbooks. A widely used metaphor for chemistry education takes the shape of a planar triangle that highlights three thinking levels in learning chemistry such as…

  20. The Journal of Kitchen Chemistry: A Tool for Instructing the Preparation of a Chemistry Journal Article

    ERIC Educational Resources Information Center

    Meyers, Jonathan K.; LeBaron, Tyler W.; Collins, David C.

    2014-01-01

    Writing assignments are typically incorporated into chemistry courses in an attempt to enhance the learning of chemistry or to teach technical writing to chemistry majors. This work addresses the development of chemistry-major writing skills by focusing on the rigorous guidelines and conventions associated with the preparation of a journal…

  1. An Approach towards Teaching Green Chemistry Fundamentals

    ERIC Educational Resources Information Center

    van Arnum, Susan D.

    2005-01-01

    A useful metrics system for the assessment of the environmental impact of chemical processes is utilized to illustrate several of the principles of green chemistry. The use of this metrics system in conjunction with laboratory experiments in green chemistry would provide for reinforcement in both the theory and practice of green chemistry.

  2. Organic Chemistry Self Instructional Package 13: Dienes.

    ERIC Educational Resources Information Center

    Zdravkovich, V.

    This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The…

  3. Organic Chemistry Self Instructional Package 12: Alkynes.

    ERIC Educational Resources Information Center

    Zdravkovich, V.

    This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The…

  4. Organic Chemistry Self Instructional Package 2: Methane.

    ERIC Educational Resources Information Center

    Zdravkovich, V.

    This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The…

  5. Organic Chemistry Self Instructional Package 17: Arenes.

    ERIC Educational Resources Information Center

    Zdravkovich, V.

    This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The…

  6. Forensic Chemistry--A Symposium Collection.

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 1985

    1985-01-01

    Presents a collection of articles to provide chemistry teachers with resource materials to add forensic chemistry units to their chemistry courses. Topics range from development of forensic science laboratory courses and mock-crime scenes to forensic serology and analytical techniques. (JN)

  7. Introducing Green Chemistry in Teaching and Research.

    ERIC Educational Resources Information Center

    Collins, Terrence J.

    1995-01-01

    Describes key elements for the research and teaching components of green chemistry, an environmentally friendly approach to chemistry. Presents an outline of an introductory course to green chemistry and other efforts at Carnegie Mellon University to incorporate the environment in a fertile manner into teaching. (JRH)

  8. Form and Function: An Organic Chemistry Module.

    ERIC Educational Resources Information Center

    Jarvis, Bruce; Mazzocchi, Paul

    This book is one in the series of Interdisciplinary Approaches to Chemistry (IAC) designed to help students discover that chemistry is a lively science and actively used to pursue solutions to the important problems of today. It is expected for students to see how chemistry takes place continuously all around and to readily understand the daily…

  9. General Chemistry in Liberal Arts Colleges.

    ERIC Educational Resources Information Center

    Finholt, Albert E.

    1978-01-01

    Discusses some issues related to chemistry curricula in liberal arts colleges. Among these issues are the nature of a liberal arts curriculum, content of chemistry course, teaching methods, technological aids to teaching, use of the laboratory, and the future of general chemistry teaching in the liberal arts colleges. (HM)

  10. A Discovery Chemistry Experiment on Buffers

    ERIC Educational Resources Information Center

    Kulevich, Suzanne E.; Herrick, Richard S.; Mills, Kenneth V.

    2014-01-01

    The Holy Cross Chemistry Department has designed and implemented an experiment on buffers as part of our Discovery Chemistry curriculum. The pedagogical philosophy of Discovery Chemistry is to make the laboratory the focal point of learning for students in their first two years of undergraduate instruction. We first pose questions in prelaboratory…

  11. 42 CFR 493.929 - Chemistry.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 5 2011-10-01 2011-10-01 false Chemistry. 493.929 Section 493.929 Public Health... Proficiency Testing Programs by Specialty and Subspecialty § 493.929 Chemistry. The subspecialties under the specialty of chemistry for which a proficiency testing program may offer proficiency testing are...

  12. 42 CFR 493.931 - Routine chemistry.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 5 2012-10-01 2012-10-01 false Routine chemistry. 493.931 Section 493.931 Public... Proficiency Testing Programs by Specialty and Subspecialty § 493.931 Routine chemistry. (a) Program content and frequency of challenge. To be approved for proficiency testing for routine chemistry, a...

  13. 42 CFR 493.929 - Chemistry.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 5 2012-10-01 2012-10-01 false Chemistry. 493.929 Section 493.929 Public Health... Proficiency Testing Programs by Specialty and Subspecialty § 493.929 Chemistry. The subspecialties under the specialty of chemistry for which a proficiency testing program may offer proficiency testing are...

  14. 40 CFR 158.2210 - Product chemistry.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Product chemistry. 158.2210 Section... REQUIREMENTS FOR PESTICIDES Antimicrobial Pesticide Data Requirements § 158.2210 Product chemistry. The product chemistry data requirements of subpart D of this part apply to antimicrobial products covered by...

  15. 40 CFR 158.2290 - Residue chemistry.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Residue chemistry. 158.2290 Section... REQUIREMENTS FOR PESTICIDES Antimicrobial Pesticide Data Requirements § 158.2290 Residue chemistry. (a) General... determine the residue chemistry data requirements for antimicrobial pesticide products. Notes that apply...

  16. 42 CFR 493.931 - Routine chemistry.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 5 2013-10-01 2013-10-01 false Routine chemistry. 493.931 Section 493.931 Public... Proficiency Testing Programs by Specialty and Subspecialty § 493.931 Routine chemistry. (a) Program content and frequency of challenge. To be approved for proficiency testing for routine chemistry, a...

  17. 42 CFR 493.931 - Routine chemistry.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 5 2014-10-01 2014-10-01 false Routine chemistry. 493.931 Section 493.931 Public... Proficiency Testing Programs by Specialty and Subspecialty § 493.931 Routine chemistry. (a) Program content and frequency of challenge. To be approved for proficiency testing for routine chemistry, a...

  18. 42 CFR 493.929 - Chemistry.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 5 2010-10-01 2010-10-01 false Chemistry. 493.929 Section 493.929 Public Health... Proficiency Testing Programs by Specialty and Subspecialty § 493.929 Chemistry. The subspecialties under the specialty of chemistry for which a proficiency testing program may offer proficiency testing are...

  19. 40 CFR 158.2210 - Product chemistry.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Product chemistry. 158.2210 Section... REQUIREMENTS FOR PESTICIDES Antimicrobial Pesticide Data Requirements § 158.2210 Product chemistry. The product chemistry data requirements of subpart D of this part apply to antimicrobial products covered by...

  20. Modern Analytical Chemistry in the Contemporary World

    ERIC Educational Resources Information Center

    Šíma, Jan

    2016-01-01

    Students not familiar with chemistry tend to misinterpret analytical chemistry as some kind of the sorcery where analytical chemists working as modern wizards handle magical black boxes able to provide fascinating results. However, this approach is evidently improper and misleading. Therefore, the position of modern analytical chemistry among…