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Sample records for brain lysophospholipids ether

  1. Synthesis of Lysophospholipids

    Directory of Open Access Journals (Sweden)

    Paola D’Arrigo

    2010-03-01

    Full Text Available New synthetic methods for the preparation of biologically active phospholipids and lysophospholipids (LPLs are very important in solving problems of membrane–chemistry and biochemistry. Traditionally considered just as second-messenger molecules regulating intracellular signalling pathways, LPLs have recently shown to be involved in many physiological and pathological processes such as inflammation, reproduction, angiogenesis, tumorogenesis, atherosclerosis and nervous system regulation. Elucidation of the mechanistic details involved in the enzymological, cell-biological and membrane-biophysical roles of LPLs relies obviously on the availability of structurally diverse compounds. A variety of chemical and enzymatic routes have been reported in the literature for the synthesis of LPLs: the enzymatic transformation of natural glycerophospholipids (GPLs using regiospecific enzymes such as phospholipases A1 (PLA1, A2 (PLA2 phospholipase D (PLD and different lipases, the coupling of enzymatic processes with chemical transformations, the complete chemical synthesis of LPLs starting from glycerol or derivatives. In this review, chemo-enzymatic procedures leading to 1- and 2-LPLs will be described.

  2. Lysophospholipid receptors LPA1–3 are not required for the inhibitory effects of LPA on mouse retinal growth cones

    OpenAIRE

    Birgbauer, Eric; Chun, Jerold

    2010-01-01

    One of the major requirements in the development of the visual system is axonal guidance of retinal ganglion cells toward correct targets in the brain. A novel class of extracellular lipid signaling molecules, lysophospholipids, may serve as potential axon guidance cues. They signal through cognate G protein-coupled receptors, at least some of which are expressed in the visual system. Here we show that in the mouse visual system, a lysophospholipid known as lysophosphatidic acid (LPA) is inhi...

  3. Dual roles of brain serine hydrolase KIAA1363 in ether lipid metabolism and organophosphate detoxification

    International Nuclear Information System (INIS)

    Serine hydrolase KIAA1363 is an acetyl monoalkylglycerol ether (AcMAGE) hydrolase involved in tumor cell invasiveness. It is also an organophosphate (OP) insecticide-detoxifying enzyme. The key to understanding these dual properties was the use of KIAA1363 +/+ (wildtype) and -/- (gene deficient) mice to define the role of this enzyme in brain and other tissues and its effectiveness in vivo in reducing OP toxicity. KIAA1363 was the primary AcMAGE hydrolase in brain, lung, heart and kidney and was highly sensitive to inactivation by chlorpyrifos oxon (CPO) (IC50 2 nM) [the bioactivated metabolite of the major insecticide chlorpyrifos (CPF)]. Although there was no difference in hydrolysis product monoalkylglycerol ether (MAGE) levels in +/+ and -/- mouse brains in vivo, isopropyl dodecylfluorophosphonate (30 mg/kg) and CPF (100 mg/kg) resulted in 23-51% decrease in brain MAGE levels consistent with inhibition of AcMAGE hydrolase activity. On incubating +/+ and -/- brain membranes with AcMAGE and cytidine-5'-diphosphocholine, the absence of KIAA1363 activity dramatically increased de novo formation of platelet-activating factor (PAF) and lyso-PAF, signifying that metabolically-stabilized AcMAGE can be converted to this bioactive lipid in brain. On considering detoxification, KIAA1363 -/- mice were significantly more sensitive than +/+ mice to ip-administered CPF (100 mg/kg) and parathion (10 mg/kg) with increased tremoring and mortality that correlated for CPF with greater brain acetylcholinesterase inhibition. Docking AcMAGE and CPO in a KIAA1363 active site model showed similar positioning of their acetyl and trichloropyridinyl moieties, respectively. This study establishes the relevance of KIAA1363 in ether lipid metabolism and OP detoxification

  4. Expression of the lysophospholipid receptor family and investigation of lysophospholipid-mediated responses in human macrophages.

    Science.gov (United States)

    Duong, Chinh Quoc; Bared, Salim Maa; Abu-Khader, Ahmad; Buechler, Christa; Schmitz, Anna; Schmitz, Gerd

    2004-06-01

    Some of the biological effects of lipoproteins have been attributed to their association with lysophosphatidic acid (LPA), lysophosphatidylcholine (LPC), sphingosine-1-phosphate (S1P) and sphingosylphosphorylcholine (SPC). These lysophospholipids mediate multiple biological responses via several G protein-coupled receptors (GPR). The expression of these receptors, however, has not been systematically investigated in primary human monocytes and macrophages as major cells involved in atherosclerosis. The mRNAs for all 15 receptors described so far were detected in monocytes, macrophages, foam cells and high density lipoprotein (HDL(3))-treated cells using real time RT-PCR. Immunoblots revealed that S1P(1), S1P(2), S1P(4), LPA(1), LPA(2) and GPR65 are expressed in monocytes and macrophages, while S1P(5) and LPA(3) have not been detected. S1P(3) was induced during differentiation but down-regulated by lipid-loading and HDL(3), whereas LPA(1) was down-regulated in differentiated macrophages. The influence of S1P on macrophages was investigated and the induction of CD32 indicates an enhanced phagocytic activity. Altogether, these data give insights into the expression and regulation of lysophospholipid receptors in primary human monocytes, macrophages and foam cells. PMID:15158762

  5. DMPD: Lysophospholipid receptors: signaling and biology. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15189145 Lysophospholipid receptors: signaling and biology. Ishii I, Fukushima N, Y...e X, Chun J. Annu Rev Biochem. 2004;73:321-54. (.png) (.svg) (.html) (.csml) Show Lysophospholipid receptors: signaling and bio...logy. PubmedID 15189145 Title Lysophospholipid receptors: signaling and biology. Authors

  6. Lysophospholipid receptors LPA1–3 are not required for the inhibitory effects of LPA on mouse retinal growth cones

    Directory of Open Access Journals (Sweden)

    Eric Birgbauer

    2010-02-01

    Full Text Available Eric Birgbauer, Jerold ChunDepartment of Molecular Biology, Helen L Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, CA, USA Abstract: One of the major requirements in the development of the visual system is axonal guidance of retinal ganglion cells toward correct targets in the brain. A novel class of extracellular lipid signaling molecules, lysophospholipids, may serve as potential axon guidance cues. They signal through cognate G protein-coupled receptors, at least some of which are expressed in the visual system. Here we show that in the mouse visual system, a lysophospholipid known as lysophosphatidic acid (LPA is inhibitory to retinal neurites in vitro when delivered extracellularly, causing growth cone collapse and neurite retraction. This inhibitory effect of LPA is both active in the nanomolar range and specific compared to the related lysophospholipid, sphingosine 1-phosphate (S1P. Knockout mice lacking three of the five known LPA receptors, LPA1–3, continue to display retinal growth cone collapse and neurite retraction in response to LPA, demonstrating that these three receptors are not required for these inhibitory effects and indicating the existence of one or more functional LPA receptors expressed on mouse retinal neurites that can mediate neurite retraction.Keywords: retinal ganglion cells, lysophosphatidic acid, axon guidance

  7. Lysophospholipids in pig pancreatic zymogen granules in relation to exocytosis

    International Nuclear Information System (INIS)

    A hypothesis to explain the stimulatory role of cyclic AMP (adenosine 3' : 5'-monophosphate) in pancreatic enzyme secretion has been tested. In this hypothesis cyclic AMP would activate a phospholipase activity, which would lead to a locally increased lysophospholipid formation, resulting in a fusion between the zymogen granule membrane and the apical plasma membrane. Cyclic AMP added to isolated pig pancreatic zymogen granules leads to an increased lysis of these granules, but the slowness of this effect makes its physiological significance dubious. In pancreatic homogenates or zymogen granules no stimulating effect of cyclic AMP on lipase or phospholipase activity could be demonstrated. Isolated zymogen granules have a high lysophospholipid content (27% of total phospholipids), consisting of the 1-acyl and 2-acyl forms of lysophosphatidylcholine and lysophosphatidylethanolamine. Experiments with radioactive phosphatidylcholine indicate that the lysophospholipids are due to the action of endogenous (phospho)lipases during the isolation procedure. It is concluded that these experiments do not lend support to the above hypothesis for the mechanism of action of cyclic AMP in pancreatic enzyme secretion. (orig.)

  8. Synthesis and evaluation of ether containing {sup 99m}Tc-nitrido dithiocarbamate complexes as brain perfusion imaging agent

    Energy Technology Data Exchange (ETDEWEB)

    Mallia, Madhava B. [Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mathur, Anupam [Medical and Biological Products Program, Board of Radiation and Isotope Technology, Mumbai 400094 (India); Subramanian, Suresh [Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Banerjee, Sharmila [Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kothari, Kanchan [Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Koiry, S.P. [TechnicalPhysics and Prototype Engineering Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Sarma, H.D. [Radiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Venkatesh, Meera [Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai 400085 (India) and Medical and Biological Products Program, Board of Radiation and Isotope Technology, Mumbai 400094 (India)]. E-mail: meerav@apsara.barc.ernet.in

    2006-03-15

    In the present study, a series of {sup 99m}Tc-nitrido dithiocarbamate complexes containing ether linkages have been prepared and their brain perfusion characteristics studied. Two primary dithiocarbamates and two secondary dithiocarbamates were synthesized in >80% yield and were characterized by elemental analyses. The ligands were then labeled using a {sup 99m}Tc-nitrido intermediate, prepared from sodium pertechnetate using commercially available nitrido kit-vials, at a low ligand concentration of 0.1 mg. The prepared complexes were obtained in more than 95% yield and were characterized by paper electrophoresis and HPLC. All the complexes were found to be neutral and eluted out as a single species in HPLC. Biodistribution studies were carried out in normal Swiss mice. All the complexes showed uptake in the brain. {sup 99m}TcN complexes of secondary dithiocarbamates showed higher initial brain uptake (5 min p.i.) than their primary amine counterparts. However, all the complexes exhibited rapid washout from the brain.

  9. Synthesis and evaluation of ether containing 99mTc-nitrido dithiocarbamate complexes as brain perfusion imaging agent

    International Nuclear Information System (INIS)

    In the present study, a series of 99mTc-nitrido dithiocarbamate complexes containing ether linkages have been prepared and their brain perfusion characteristics studied. Two primary dithiocarbamates and two secondary dithiocarbamates were synthesized in >80% yield and were characterized by elemental analyses. The ligands were then labeled using a 99mTc-nitrido intermediate, prepared from sodium pertechnetate using commercially available nitrido kit-vials, at a low ligand concentration of 0.1 mg. The prepared complexes were obtained in more than 95% yield and were characterized by paper electrophoresis and HPLC. All the complexes were found to be neutral and eluted out as a single species in HPLC. Biodistribution studies were carried out in normal Swiss mice. All the complexes showed uptake in the brain. 99mTcN complexes of secondary dithiocarbamates showed higher initial brain uptake (5 min p.i.) than their primary amine counterparts. However, all the complexes exhibited rapid washout from the brain

  10. LC-MS analysis of phospholipids and lysophospholipids in human bronchoalveolar lavage fluid

    NARCIS (Netherlands)

    Barroso, B.; Bischoff, Rainer

    2005-01-01

    A reversed phase HPLC method was developed for the simultaneous analysis of different phospholipids and lysophospholipid, in human bronchoalveolar lavage fluid (BALF). Separation was achieved using a pellicular C8 column at elevated temperatures with an increasing gradient of acetonitrile containing

  11. Human neural progenitors express functional lysophospholipid receptors that regulate cell growth and morphology

    Directory of Open Access Journals (Sweden)

    Callihan Phillip

    2008-12-01

    Full Text Available Abstract Background Lysophospholipids regulate the morphology and growth of neurons, neural cell lines, and neural progenitors. A stable human neural progenitor cell line is not currently available in which to study the role of lysophospholipids in human neural development. We recently established a stable, adherent human embryonic stem cell-derived neuroepithelial (hES-NEP cell line which recapitulates morphological and phenotypic features of neural progenitor cells isolated from fetal tissue. The goal of this study was to determine if hES-NEP cells express functional lysophospholipid receptors, and if activation of these receptors mediates cellular responses critical for neural development. Results Our results demonstrate that Lysophosphatidic Acid (LPA and Sphingosine-1-phosphate (S1P receptors are functionally expressed in hES-NEP cells and are coupled to multiple cellular signaling pathways. We have shown that transcript levels for S1P1 receptor increased significantly in the transition from embryonic stem cell to hES-NEP. hES-NEP cells express LPA and S1P receptors coupled to Gi/o G-proteins that inhibit adenylyl cyclase and to Gq-like phospholipase C activity. LPA and S1P also induce p44/42 ERK MAP kinase phosphorylation in these cells and stimulate cell proliferation via Gi/o coupled receptors in an Epidermal Growth Factor Receptor (EGFR- and ERK-dependent pathway. In contrast, LPA and S1P stimulate transient cell rounding and aggregation that is independent of EGFR and ERK, but dependent on the Rho effector p160 ROCK. Conclusion Thus, lysophospholipids regulate neural progenitor growth and morphology through distinct mechanisms. These findings establish human ES cell-derived NEP cells as a model system for studying the role of lysophospholipids in neural progenitors.

  12. Synthesis and characterization of 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE) and structurally related compounds evidenced in seal blubber and brain.

    Science.gov (United States)

    von der Recke, Roland; Vetter, Walter

    2007-03-01

    The unknown compound UBC-1 previously described as the major organobromine contamination in the blubber extract of a hooded seal (Cystophora cristata) from the Barents Sea was identified as 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE). DPTE, which is the main component of the brominated flame retardant (BFR) Bromkal 73-5 PE, was synthesized by electrophilic addition of bromine to allyl-2,4,6-tribromophenyl ether (ATE). The chirality of DPTE was proven by gas chromatographic enantioseparation of the synthesized racemate. On the basis of GC/ECNI-MS ion chromatograms (m/z79 and 81), DPTE was the dominating organobromine compound in blubber and brain samples of hooded seals and harp seals (Phoca groenlandica) from the Barents and Greenland Seas. The concentrations of DPTE in blubber and brain were up to 470 and 340 microg/kg wet weight. Next to DPTE, the natural dibromo-trichloromonoterpene (MHC-1), the anthropogenic BDE 47 and BDE 99, as well as ATE, 3,5-dibromo-2-(2',4'-dibromo)-phenoxyanisole (6-MeO-BDE 47), 2-bromoallyl-2,4,6-tribromophenyl ether (BATE), and 4,6-dibromo-2-(2',4'-dibromo)-phenoxyanisole (2'-MeO-BDE 68) were present with decreasing relevance. BATE, which was detected for the first time in environmental samples, was synthesized from DPTE by E2 elimination. In brain samples of the harp seals, DPTE, ATE, and BATE were the most abundant organobromine compounds, whereas polybrominated diphenyl ethers (PBDEs) and MHC-1 were virtually absent. This indicated that DPTE, ATE, and BATE were able to penetrate the blood-brain barrier. The general co-occurrence of ATE and BATE in samples contaminated with DPTE support the hypothesis that these compounds are biotransformation products of DPTE. Anaerobic transformation studies of DPTE with super-reduced corrinoids resulted in the formation of ATE. Furthermore, 2,4,6-tribromophenol (TBP) and two other unknown minor transformation products were detected. PMID:17396646

  13. Acute developmental exposure to polybrominated diphenyl ether 47 (PBDE 47) alters dopamine concentration within the brains of male mice.

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDEs) are commonly used as commercial flame retardants in a variety of products including plastics and textiles. Previous studies in our laboratory and in the literature have shown that exposure to a specific PBDE congener, PBDE 47, during a criti...

  14. Modulation of the Cold-Activated Channel TRPM8 by Lysophospholipids and Polyunsaturated Fatty Acids

    OpenAIRE

    Andersson, David A; Nash, Mark; Bevan, Stuart

    2007-01-01

    We investigated the role of phospholipase A2 (PLA2) and the effects of PLA2 products (polyunsaturated fatty acids and lysophospholipids) on the cold-sensitive channel transient receptor potential (melastatin)-8 (TRPM8), heterologously expressed in Chinese hamster ovary cells. TRPM8 responses to cold and the agonist icilin were abolished by inhibitors of the calcium-independent (iPLA2) form of the enzyme, whereas responses to menthol were less sensitive to iPLA2 inhibition. Inhibition of PLA2 ...

  15. Double-bilayer: a new phase formed by lysophospholipids and the corresponding fatty acid

    Directory of Open Access Journals (Sweden)

    Sérgio S. Funari

    2009-01-01

    Full Text Available The product of catalytic activity of the enzyme phospholipase A2, which resembles the core unit of animal toxins, on phospholipids is a 1:1 mixture of lysolipid and fatty acid. This mixture was studied by time-resolved simultaneous small- and wide angle x-ray diffraction over the temperature range from 23 to 53.5ºC. An unusually large lamellar structure was observed, with d = 11 nm, contradicting the complex functional dimer model between lysolipid and fatty acid. It can be explained by formation of a "double-bilayer", a new phase consisting of two different bilayers, one formed by lysophospholipid and other by fatty acid, bound together by head group interactions. Its strucutre was confirmed by simulations of the X-ray scattering pattern.

  16. Addition of lysophospholipids with large head groups to cells inhibits Shiga toxin binding.

    Science.gov (United States)

    Ailte, Ieva; Lingelem, Anne Berit Dyve; Kavaliauskiene, Simona; Bergan, Jonas; Kvalvaag, Audun Sverre; Myrann, Anne-Grethe; Skotland, Tore; Sandvig, Kirsten

    2016-01-01

    Shiga toxin (Stx), an AB5 toxin, binds specifically to the neutral glycosphingolipid Gb3 at the cell surface before being transported into cells. We here demonstrate that addition of conical lysophospholipids (LPLs) with large head groups inhibit Stx binding to cells whereas LPLs with small head groups do not. Lysophosphatidylinositol (LPI 18:0), the most efficient LPL with the largest head group, was selected for in-depth investigations to study how the binding of Stx is regulated. We show that the inhibition of Stx binding by LPI is reversible and possibly regulated by cholesterol since addition of methyl-β-cyclodextrin (mβCD) reversed the ability of LPI to inhibit binding. LPI-induced inhibition of Stx binding is independent of signalling and membrane turnover as it occurs in fixed cells as well as after depletion of cellular ATP. Furthermore, data obtained with fluorescent membrane dyes suggest that LPI treatment has a direct effect on plasma membrane lipid packing with shift towards a liquid disordered phase in the outer leaflet, while lysophosphoethanolamine (LPE), which has a small head group, does not. In conclusion, our data show that cellular treatment with conical LPLs with large head groups changes intrinsic properties of the plasma membrane and modulates Stx binding to Gb3. PMID:27458147

  17. Inhibition of β-bungarotoxin binding to brain membranes by mast cell degranulating peptide, toxin I, and ethylene glycol bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid

    International Nuclear Information System (INIS)

    The presynaptically active snake venom neurotoxin β-bungarotoxin (β-Butx) is known to affect neurotransmitter release by binding to a subtype of voltage-activated K+ channels. Here the authors show that mast cell degranulating (MCD) peptide from bee venom inhibits the binding of 125I-labeled β-Butx to chick and rat brain membranes with apparent K/sub i/ values of 180 nM and 1100 nM, respectively. The mechanisms of inhibition of MCD peptide is noncompetitive, as is inhibition of 125I-β-Butx binding by the protease inhibitor homologue from mamba venom, toxin I. β-Butx and its binding antagonists thus bind to different sites of the same membrane protein. Removal of Ca2+ by ethylene glycol bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid inhibits the binding of 125I-β-Butx by lowering its affinity to brain membranes

  18. Brain

    Science.gov (United States)

    ... will return after updating. Resources Archived Modules Updates Brain Cerebrum The cerebrum is the part of the ... the outside of the brain and spinal cord. Brain Stem The brain stem is the part of ...

  19. Ether formulations of relativity

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, M.C.

    1980-12-01

    Contemporary ether theories are surveyed and criticized, especially those formally identical to orthodox Relativity. The historical development of Relativity, Special and General, in terms of an ether, is briefly indicated. Classical interpretations of Generalized Relativity using ether are compared to Euclidean formulations using a background space. The history of a sub-group of theories, formulating a 'new' Relativity involving modified transforms, is outlined. According to the theory with which they agree, recent supposed detections of drift are classified and criticized. Cosmological evidence suggesting an ether is mentioned. Only ether theories formally identical to Relativity have been published in depth. They stand criticized as being contrary to the positivist spirit. The history of mechanical analogues is traced, from Hartley's representing gravitating matter as spherical standing waves, to recent suggestions that vortex-sponge might model electromagnetic, quantum, uncertainty and faster-than-light phenomena. Contemporary theories are particular physical theories, themselves 'second interpretations' of a primary mathematical model. Mechanical analogues are auxiliary, not necessary, to other theory, disclosing relationships between classical and non-classical descriptions of assemblies charging state. The ether-relativity polemic, part of a broader dispute about relativity, is founded on mistaken conceptions of the roles of mathematical and physical models, mechanical analogues; and a distored view of history, which indicates that ether theories have become relativistic. 103 references.

  20. Ether formulations of relativity

    International Nuclear Information System (INIS)

    Contemporary ether theories are surveyed and criticised, especially those formally identical to orthodox Relativity. The historical development of Relativity, Special and General, in terms of an ether, is briefly indicated. Classical interpretations of Generalized Relativity using ether are compared to Euclidean formulations using a background space. The history of a sub-group of theories, formulating a 'new' Relativity involving modified transforms, is outlined. According to the theory with which they agree, recent supposed detections of drift are classified and criticised. Cosmological evidence suggesting an ether is mentioned. Only ether theories formally identical to Relativity have been published in depth. They stand criticised as being contrary to the positivist spirit. The history of mechanical analogues is traced, from Hartley's representing gravitating matter as spherical standing waves, to recent suggestions that vortex-sponge might model electromagnetic, quantum, uncertainty and faster-than-light phenomena. Contemporary theories are particular physical theories, themselves 'second interpretations' of a primary mathematical model. Mechanical analogues are auxiliary, not necessary, to other theory, disclosing relationships between classical and non-classical descriptions of assemblies charging state. The ether-relativity polemic, part of a broader dispute about relativity, is founded on mistaken conceptions of the roles of mathematical and physical models, mechanical analogues; and a distored view of history, which indicates that ether theories have become relativistic. (author)

  1. Catalytic oxidation of dimethyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Zelenay, Piotr; Wu, Gang; Johnston, Christina M.; Li, Qing

    2016-05-10

    A composition for oxidizing dimethyl ether includes an alloy supported on carbon, the alloy being of platinum, ruthenium, and palladium. A process for oxidizing dimethyl ether involves exposing dimethyl ether to a carbon-supported alloy of platinum, ruthenium, and palladium under conditions sufficient to electrochemically oxidize the dimethyl ether.

  2. First International Conference on Lysophospholipids and Related Bioactive Lipids in Biology and Disease Sponsored by the Federation of American Societies of Experimental Biology

    OpenAIRE

    Goetzl, Edward J.; Tigyi, Gabor J.; Timothy Hla

    2001-01-01

    The First International Conference on “Lysophospholipids and Related Bioactive Lipids in Biology and Diseases” was held in Tucson, AZ on June 10�14, 2001, under the sponsorship of the Federation of American Societies of Experimental Biology (FASEB). More than 100 scientists from 11 countries discussed the recent results of basic and clinical research in the broad biology of this emerging field. Immense progress was reported in defining the biochemistry of generation and biology of cellular ef...

  3. Lysophospholipid presentation by CD1d and recognition by a human Natural Killer T-cell receptor

    Energy Technology Data Exchange (ETDEWEB)

    López-Sagaseta, Jacinto; Sibener, Leah V.; Kung, Jennifer E.; Gumperz, Jenny; Adams, Erin J. (UC); (UW-MED)

    2014-10-02

    Invariant Natural Killer T (iNKT) cells use highly restricted {alpha}{beta} T cell receptors (TCRs) to probe the repertoire of lipids presented by CD1d molecules. Here, we describe our studies of lysophosphatidylcholine (LPC) presentation by human CD1d and its recognition by a native, LPC-specific iNKT TCR. Human CD1d presenting LPC adopts an altered conformation from that of CD1d presenting glycolipid antigens, with a shifted {alpha}1 helix resulting in an open A pocket. Binding of the iNKT TCR requires a 7-{angstrom} displacement of the LPC headgroup but stabilizes the CD1d-LPC complex in a closed conformation. The iNKT TCR CDR loop footprint on CD1d-LPC is anchored by the conserved positioning of the CDR3{alpha} loop, whereas the remaining CDR loops are shifted, due in part to amino-acid differences in the CDR3{beta} and J{beta} segment used by this iNKT TCR. These findings provide insight into how lysophospholipids are presented by human CD1d molecules and how this complex is recognized by some, but not all, human iNKT cells.

  4. The compound ethers of glycerin

    International Nuclear Information System (INIS)

    In this chapter of book authors describe several methods of receiving of compound ethers of glycerin. The important technic significance have compound glycerin ether and nitric acid. This compound receive by reaction of glycerin with fuming nitric acid

  5. Propenyl ether monomers for photopolymerization

    Science.gov (United States)

    Crivello, James V.

    1996-01-01

    Propenyl ether monomers of formula V A(OCH.dbd.CHCH.sub.3).sub.n wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  6. First International Conference on Lysophospholipids and Related Bioactive Lipids in Biology and Disease Sponsored by the Federation of American Societies of Experimental Biology

    Directory of Open Access Journals (Sweden)

    Edward J. Goetzl

    2001-01-01

    Full Text Available The First International Conference on “Lysophospholipids and Related Bioactive Lipids in Biology and Diseases” was held in Tucson, AZ on June 10�14, 2001, under the sponsorship of the Federation of American Societies of Experimental Biology (FASEB. More than 100 scientists from 11 countries discussed the recent results of basic and clinical research in the broad biology of this emerging field. Immense progress was reported in defining the biochemistry of generation and biology of cellular effects of the bioactive lysophospholipids (LPLs. These aspects of LPLs described at the conference parallel in many ways those of the eicosanoid mediators, such as prostaglandins and leukotrienes. As for eicosanoids, the LPLs termed lysophosphatidic acid (LPA and sphingosine 1-phosphate (S1P are produced enzymatically from phospholipid precursors in cell membranes and act on cells at nanomolar concentrations through subfamilies of receptors of the G protein–coupled superfamily. The rate-limiting steps in production of LPLs were reported to be controlled by specific phospholipases for LPA and sphingosine kinases for S1P. The receptor subfamilies formerly were designated endothelial differentiation gene-encoded receptors or Edg Rs for their original discovery in endothelial cells. A currently active nomenclature committee at this conference suggested the ligand-based names: S1P1 = Edg-1, S1P2 = Edg-5, S1P3 = Edg-3, S1P4 = Edg-6, and S1P5 = Edg-8; LPA1 = Edg-2, LPA2 = Edg-4, and LPA3 = Edg-7 receptors. Several families of lysophospholipid phosphatases (LPPs have been characterized, which biodegrade LPA, whereas S1P is inactivated with similar rapidity by both a lyase and S1P phosphatases.

  7. Bacterial degradation of glycol ethers.

    Science.gov (United States)

    Kawai, F

    1995-12-01

    Assimilation of ethyleneglycol (EG) ethers by polyethyleneglycol-utilizing bacteria was examined. Ethyleneglycol ether-utilizing bacteria were also isolated from soil and activated sludge samples by enrichment-culture techniques. Three strains (4-5-3, EC 1-2-1 and MC 2-2-1) were selected and characterized as Pseudomonas sp. 4-5-3, Xanthobacter autotrophicus, and an unidentified gram-negative, non-spore-forming rod respectively. Their growth characteristics were examined: Pseudomonas sp. 4-5-3 assimilated EG (diethyleneglycol, DEG) monomethyl, monoethyl and monobutyl ethers, DEG, propanol and butanol. X. autotrophicus EC 1-2-1 grew well on EG monoethyl and monobutyl ethers, EG and primary alcohols (C1-C4), and slightly on EG monomethyl ether. The strain MC 2-2-1 grew on EG monomethyl ether, EG, primary alcohols (C1-C4), and 1,2-propyleneglycol (PG). The mixed culture of Pseudomonas sp. 4-5-3 and X. autotrophicus EC 1-2-1 showed better growth and improved degradation than respective single cultures towards EG monomethyl, monoethyl or monobutyl ethers. Intact cells of Pseudomonas sp. 4-5-3 degraded various kinds of monoalkyl ethers, which cannot be assimilated by the strain. Metabolic products were characterized from reaction supernatants of intact cells of Pseudomonas sp. 4-5-3 with EG or DEG monoethyl ethers: they were analyzed by thin-layer chromatography and GC-MS and found to be ethoxyacetic acid and ethoxyglycoxyacetic acid. Also, PG monoalkyl ethers (C1-C4), dipropyleneglycol monoethyl and monomethyl ethers and tripropyleneglycol monomethyl ether were assimilated by polypropyleneglycol-utilizing Corynebacterium sp. 7. PMID:8597556

  8. Ether and Relativity

    CERN Document Server

    Farhoudi, Mehrdad

    2015-01-01

    We consider one of the fundamental debates in performing the relativity theory, namely, the ether and the relativity points of view, in a way to aid the learning of the subjects. In addition, we present our views and prospects while describing the issues that being accessible to many physicists and allowing broader views. Also, we very briefly review the two almost recent observations of the Webb redshift and the ultra high-energy cosmic rays, and the modified relativity models that have been presented to justify them, wherein we express that these justifications have not been performed via a single model with a single mechanism.

  9. Ether and Relativity

    Science.gov (United States)

    Farhoudi, Mehrdad; Yousefian, Maysam

    2016-05-01

    We consider one of the fundamental debates in performing the relativity theory, namely, the ether and the relativity points of view, in a way to aid the learning of the subjects. In addition, we present our views and prospects while describing the issues that being accessible to many physicists and allowing broader views. Also, we very briefly review the two almost recent observations of the Webb redshift and the ultra high energy cosmic rays, and the modified relativity models that have been presented to justify them, wherein we express that these justifications have not been performed via a single model with a single mechanism.

  10. Direct Dimethyl Ether Synthesis

    Institute of Scientific and Technical Information of China (English)

    Takashi Ogawa; Norio Inoue; Tutomu Shikada; Yotaro Ohno

    2003-01-01

    Dimethyl ether (DME) is a clean and economical alternative fuel which can be produced from natural gas through synthesis gas. The properties of DME are very similar to those of LP gas. DME can be used for various fields as a fuel such as power generation, transportation, home heating and cooking,etc. It contains no sulfur or nitrogen. It is not corrosive to any metal and not harmful to human body. An innovative process of direct synthesis of DME from synthesis gas has been developed. Newly developed catalyst in a slurry phase reactor gave a high conversion and high selectivity of DME production. One and half year pilot scale plant (5 tons per day) testing, which was supported by METI, had successfully finished with about 400 tons DME production.

  11. Rearrangements of Cycloalkenyl Aryl Ethers

    Directory of Open Access Journals (Sweden)

    Mercedesz Törincsi

    2016-04-01

    Full Text Available Rearrangement reactions of cycloalkenyl phenol and naphthyl ethers and the acid-catalyzed cyclization of the resulting product were investigated. Claisen rearrangement afforded 2-substituted phenol and naphthol derivatives. Combined Claisen and Cope rearrangement resulted in the formation of 4-substituted phenol and naphthol derivatives. In the case of cycloocthylphenyl ether the consecutive Claisen and Cope rearrangements were followed by an alkyl migration. The mechanism of this novel rearrangement reaction is also discussed.

  12. SYNTHESIS AND CRYSTALLIZATION BEHAVIOR OF POLY(ETHER ETHER KETONE ETHER KETONE) (PEEKEK)

    Institute of Scientific and Technical Information of China (English)

    Zhao-bin Qiu; Zhi-shen Mo; Ying-ning Yu; Hong-fang Zhang; Xian-hong Wang

    2000-01-01

    In this paper, the synthesis and crystallization behavior of poly(ether ether ketone ether ketone) (PEEKEK) are reported. PEEKEK was prepared from 4,4'-bis(p-fluorobenzoyl) diphenyl ether (4,4'-FBDE) and hydroquinone along the nucleophilic substitution route. The thermal properties were investigated by using DSC and TGA. The crystallization behavior of PEEKEK under several conditions, i.e., crystallization from the molten state (melt crystallization), crystallization from a quenched sample (cold crystallization) and crystallization induced by exposing glassy sample to methylene chloride (solvent-induced crystallization) has also been investigated. The results show that crystallization of PEEKEK could be induced by the above methods, and no polymorphism was found. The differences in the crystallization of PEEKEK induced by the above methods are seen in their degree of crystallinity.

  13. The unsaturated simple ethers of glycerin

    International Nuclear Information System (INIS)

    To the unsaturated simple ethers of glycerin related allyl, vinyl ethers, which can be mono-, di- and three-substitutes. Besides there are known compounds, which contain simultaneously saturate and unsaturated radicals in molecule

  14. Lysophospholipid receptors are differentially expressed in rat terminal Schwann cells, as revealed by a single cell rt-PCR and in situ hybridization.

    Science.gov (United States)

    Kobashi, Hiroaki; Yaoi, Takeshi; Oda, Ryo; Okajima, Seiichiro; Fujiwara, Hiroyoshi; Kubo, Toshikazu; Fushiki, Shinji

    2006-04-22

    Terminal Schwann cells (TSCs) that cover motor neuron terminals, are known to play an important role in maintaining neuromuscular junctions, as well as in the repair process after nerve injury. However, the molecular characteristics of TSCs remain unknown, because of the difficulties in analyzing them due to their paucity. By using our previously reported method of selectively and efficiently collecting TSCs, we have analyzed the difference in expression patterns of lysophospholipid (LPL) receptor genes (LPA1, LPA2, LPA3, S1P1, S1P2, S1P3, S1P4, and S1P5) between TSCs and myelinating Schwann cells (MSCs). LPL, which includes lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P), is the bioactive lipid that induces a myriad of cellular responses through specific members of G-protein coupled receptors for LPA. It turned out that LPA3 was expressed only in TSCs, whereas S1P1 was expressed in TSCs and skeletal muscle, but not in MSCs. Other types of LPL receptor genes, including LPA1, S1P2, S1P3, S1P4, were expressed in both types of Schwann cells. None of the LPL receptor gene family showed MSCs-specific expression. PMID:17375210

  15. The simple ethers of glycerin

    International Nuclear Information System (INIS)

    From glycerin derivatives the considerable interest is present simple ethers because many of them are biological active and found wide practical using as an effect drugs, inters for thin organic synthesis, vehicle for injections, regulators of plants growth, reagents, components for perfumery-cosmetic goods and etc

  16. A new alternative to expandable pedicle screws: Expandable poly-ether-ether-ketone shell.

    Science.gov (United States)

    Demir, Teyfik

    2015-05-01

    Screw pullout is a very common problem in the fixation of sacrum with pedicle screws. The principal cause of this problem is that the cyclic micro motions in the fixation of sacrum are higher than the other regions of the vertebrae that limit the osteo-integration between bone and screw. In addition to that, the bone quality is very poor at sacrum region. This study investigated a possible solution to the pullout problem without the expandable screws' handicaps. Newly designed poly-ether-ether-ketone expandable shell and classical pedicle screws were biomechanically compared. Torsion test, pullout tests, fatigue tests, flexion/extension moment test, axial gripping capacity tests and torsional gripping capacity tests were conducted in accordance with ASTM F543, F1798 and F1717. Standard polyurethane foam and calf vertebrae were used as embedding medium for pullout tests. Classical pedicle screw pullout load on polyurethane foam was 564.8 N compared to the failure load for calf vertebrae's 1264 N. Under the same test conditions, expandable poly-ether-ether-ketone shell system's pullout loads from polyurethane foam and calf vertebrae were 1196.3 and 1890 N, respectively. The pullout values for expandable poly-ether-ether-ketone shell were 33% and 53% higher than classical pedicle screw on polyurethane foam and calf vertebrae, respectively. The expandable poly-ether-ether-ketone shell exhibited endurance on its 90% of yield load. Contrary to poly-ether-ether-ketone shell, classical pedicle screw exhibited endurance on 70% of its yield load. Expandable poly-ether-ether-ketone shell exhibited much higher pullout performance than classical pedicle screw. Fatigue performance of expandable poly-ether-ether-ketone shell is also higher than classical pedicle screw due to damping the micro motion capacity of the poly-ether-ether-ketone. Expandable poly-ether-ether-ketone shell is a safe alternative to all other expandable pedicle screw systems on mechanical perspective

  17. Ether symmetry unification theory (ESU)

    International Nuclear Information System (INIS)

    The ether symmetry unification (ESU) theory postulates a mechanism that accounts for the formation of the universe as well as the formation of the original mass particles following the big bang. The essential role of the medium-vacuum of the theory of prerelativity is explained. The ultra-high energy particles described in the Ether Symmetry Unification Theory are compared with high energy magnetic monopoles described by Supersymmetry. Phase transitions of high energy events to low energy events and the associated media-vacua involved, postulated by the ESU, are then compared to the low energy events of the standard model within the critical phases of the first two seconds of quantum field theory's time line

  18. Review of glycol ether and glycol ether ester solvents used in the coating industry.

    OpenAIRE

    Smith, R.L.

    1984-01-01

    Ethylene oxide-based glycol ether and glycol ether ester solvents have been used in the coatings industry for the past fifty years. Because of their excellent performance properties (evaporation rate, blush resistance, flow-out and leveling properties, solubility for coating resins, solvent activity, mild odor, good coupling ability, good solvent release) a complete line of ethylene oxide-based solvents of various molecular weights has been developed. These glycol ether and glycol ether ester...

  19. Flow-Induced Crystallization of Poly(ether ether ketone)

    Science.gov (United States)

    Nazari, Behzad; Rhoades, Alicyn; Colby, Ralph

    The effects of an interval of shear above the melting temperature Tm on subsequent isothermal crystallization below Tm is reported for the premier engineering thermoplastic, poly(ether ether ketone) (PEEK). The effect of shear on the crystallization rate of PEEK is investigated by means of rheological techniques and differential scanning calorimetry (DSC) under a protocol of imposing shear in a rotational cone and plate rheometer and monitoring crystallization after quenching. The rate of crystallization at 320 °C was not affected by shear for shear rates <7 s-1 at 350 °C, whereas intervals of adequate shear at higher shear rates prior to the quench to 320 °C accelerated crystallization significantly. As the duration of the interval of shear above 7 s-1 is increased, the crystallization time decreases but at each shear rate eventually saturates once the applied specific work exceeds ~120 MPa. The annealing of the flow-induced precursors was also investigated. The nuclei were fairly persistent at temperatures close to 350 °C, however very unstable at temperatures above 375 °C. This suggests that the nanostructures formed under shear might be akin to crystalline lamellae of greater thickness, compared to quiescently crystallized lamellae.

  20. Comparison of Properties among Dendritic and Hyperbranched Poly(ether ether ketones and Linear Poly(ether ketones

    Directory of Open Access Journals (Sweden)

    Atsushi Morikawa

    2016-02-01

    Full Text Available Poly(ether ether ketone dendrimers and hyperbranched polymers were prepared from 3,5-dimethoxy-4′-(4-fluorobenzoyldiphenyl ether and 3,5-dihydroxy-4′-(4-fluorobenzoyldiphenyl ether through aromatic nucleophilic substitution reactions. 1-(tert-Butyldimethylsiloxy-3,5-bis(4-fluorobenzoylbenzene was polycondensed with bisphenols, followed by cleavage of the protective group to form linear poly(ether ketones having the same hydroxyl groups in the side chains as the chain ends of the dendrimer and hyperbranched polymers. Their properties, such as solubilities, reduced viscosities, and thermal properties, were compared with one another. Similar comparisons were also carried out among the corresponding methoxy group polymers, and the size of the molecules was shown to affect the properties.

  1. Atmospheric lifetimes of selected fluorinated ether compounds

    DEFF Research Database (Denmark)

    Heathfield, A.E.; Anastasi, C.; Pagsberg, Palle Bjørn;

    1998-01-01

    Atmospheric lifetimes have been estimated for a selection of ethers, the latter representing a class of compounds being considered as replacements for chlorofluorocarbons. The estimates are based on laboratory measurements of rate constants for the reaction of the OH radical with the ethers, and ...

  2. Unitary information ether and its possible applications

    International Nuclear Information System (INIS)

    The idea of information ether as the unitary information field is developed. It rests on the assumption that the notion of information is a fundamental category in the description of reality and that it can be defined independently from the notion of probability itself. It is shown that the information ether provides a deterministic background for the nonlinear wave hypothesis and quantum cybernetics. (orig.)

  3. Solvent-induced crystallization of poly(ether ether ketone)

    Science.gov (United States)

    McPeak, Jennifer Lynne

    The purpose of this study was learn how the diffusion, swelling, and crystallization processes are coupled during solvent-induced crystallization of poly(ether ether ketone) (PEEK). Unoriented amorphous PEEK films were immersed in aprotic organic liquids at ambient temperature and bulk properties or characteristics were monitored as a function of immersion time. The sorption behavior, T g and Tm° suppression, crystallinity, and dynamic mechanical response were correlated as a function of solvent chemistry and immersion time. The saturation time of methylene chloride, 1,3-dichloropropane, tetrahydrofuran, cyclopentanone, chlorobenzene, toluene, diethyl ketone, and ethylbenzene in amorphous PEEK films were found to range from hours to days depending on the level of polymer-solvent interactions. In-situ isochronal DMA spectra show that the Tg of PEEK was suppressed from 150°C to below ambient temperature such that crystallization was kinetically feasible during ambient immersion. In addition, an increase in viscoelastic dispersion was attributed to the presence of crystallinity. From dynamic mass uptake and wide-angle x-ray diffraction (WAXD) results, it was found that the bulk sorption rate was equal to the bulk crystallization rate for all solvent systems that promoted SINC and PEEK exhibited diffusion-limited crystallization, irrespective of the nature of the transport mechanism. In addition, the solvent-induced crystals exhibit preferred orientation as supported by photographic WAXD. A distinct sorption front, observed with scanning electron microscopy, further supports the scenario of diffusion-controlled crystallization and one-dimensional diffusion. Isothermal DMA spectra for THF, cyclopentanone, and chlorobenzene, indicate that, as the solvent diffuses into the films, the stiffness of the polymer decreases at short times, begins to increase, and then reaches a relatively time-independent value. It was determined that the initial decrease in the storage

  4. Activity relationships for aromatic crown ethers

    CERN Document Server

    Wilson, M J

    1998-01-01

    This thesis involves an investigation of aromatic crown ethers and a study of their binding constants for alkali metals. The study was motivated by the current needs of the semiconductor industry to improve the scavenging of mobile ions from fabricated circuits. A number of aromatic crown ethers have been sulphonated in an attempt to improve their water solubility and cation binding activity. These materials have been extensively studied and their binding activity determined. In collaboration with a molecular modelling study, the effect of ionisable sulphonate groups on the macrocycles' behaviour has been investigated. The broader issue of the effect of substituents in aromatic crown ethers has also been studied with the preparation of a wide range of substituted crown ethers. The cation binding activity of these materials has been found to bear a simple relationship to the electron withdrawing nature of the aromatic substituents. This relationship can be accurately monitored using electronic charge densities...

  5. Exogenous ether lipids predominantly target mitochondria

    DEFF Research Database (Denmark)

    Kuerschner, Lars; Richter, Doris; Hannibal-Bach, Hans Kristian;

    2012-01-01

    Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high......, accumulated to mitochondria and induced morphological changes and cellular apoptosis. These data indicate that edelfosine could exert its pro-apoptotic power by targeting and damaging mitochondria and thereby inducing cellular apoptosis. In general, this study implies an important role of mitochondria in...

  6. Bulk and interfacial properties of cellulose ethers

    OpenAIRE

    Bodvik, Rasmus

    2012-01-01

    This work summarizes several studies that all concern cellulose ethers of the types methylcellulose (MC) hydroxypropylmethylcellulose (HPMC) and ethyl(hydroxyethyl)cellulose (EHEC). They share the feature of negative temperature response, as they are soluble in water at room temperature but phase separate and sometimes form gels at high temperatures. The different types of viscosity transitions occurring in these three cellulose ethers are well-known. However, earlier studies have not solved ...

  7. Thin sulfonated poly(ether ether ketone) films for the dehydration of compressed carbon dioxide

    NARCIS (Netherlands)

    Koziara, B.T.

    2015-01-01

    In this thesis, the properties of thin films from highly sulfonated poly(ether ether ketone) (SPEEK) have been investigated within the context of their application as membranes for the dehydration of compressed carbon dioxide. Spectroscopic ellipsometry has been used as the predominant measurement t

  8. Injection characteristics of dimethyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Glensvig, M.

    1996-09-01

    Dimethyl ether (DME) has proved to be a new ultra-clean alternative fuel for diesel engines. Engine tests have shown considerably lower NO{sub x} emissions, no particle emissions and lower noise compared to that obtained from normal diesel engine operation. DME also has demonstrated favorable response to Exhaust Gas Recirculation (EGR). The purpose of this investigation was to achieve a better understanding of the fundamental spray behavior of DME. Fundamental spray behaviour was characterized by fuel spray penetration and angle, atomization and droplet size and evaporation. The influence of fuel characteristics, nozzle geometry and ambient pressure on the DME and diesel spray behavior was investigated. Fuel was injected into an unheated injection chamber with a ambient pressure of 15 bar and 25 bar, respectively, giving a simplified simulation of the environment in an operating engine. Two nozzles were studied: a single hole nozzle and a pintle nozzle. A conventional fuel injection system was used for both nozzles. Injection parameters of RPM, throttle position, fuel line length and chamber environment were held constant for both nozzles. The sprays were visualized using schlieren and high speed photography. Results show that the general appearance of the DME spray is similar to that of diesel spray. The core of the DME spray seems less dense and the spray tip less sharp compared to diesel spray, indicating smaller droplets with a lower momentum in the core of the DME spray. Schlieren film shows that with both DME and diesel fuel, the spray tip only consists of liquid and that evaporation occurs after a brief time interval. Penetration of DME is about one third that of diesel using the pintle nozzle. Also, the spray angle is considerably larger for the DME spray compared to the diesel spray. A comparatively smaller difference in penetration is observed using the hole nozzle. Differences in penetration for the hole nozzle are within the limit of the penetration

  9. A Convenient and Efficient Procedure for Oxime Ethers

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Acetophenone oxime and benzaldehyde oxime were converted to oxime ethers in the presence of alkyl halide or methyl sulfate and KOH in aqueous DMSO in 5 to 70 min. The yields of oxime ethers were 70 - 96%.

  10. 40 CFR 721.3435 - Butoxy-substituted ether alkane.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Butoxy-substituted ether alkane. 721... Substances § 721.3435 Butoxy-substituted ether alkane. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as butoxy-substituted ether...

  11. On new physical reality (on ψ-ether)

    International Nuclear Information System (INIS)

    It is shown that there exists a new physical reality - the ψ-ether. All the achievements of quantum mechanics and quantum field theory are due to the fact that both the theories include the influence of ψ-ether on the physical processes occurring in the Universe. Physics of the XX century was first of all the physics of ψ-ether

  12. Finkelstein Reaction in Functionalized Crown-ether Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    Xiao Hua WANG; Han Zhi WANG; Hui LIU; Yuan KOU

    2006-01-01

    Functional crown-ether ionic liquids were used as catalytic green solvents of Finkelstein reaction of 1-bromooctane and iodide. The rate and yield of the reaction were obvious improved compared with that using crown ether in water. No free crown ether loss was observed after reaction.

  13. Alkyl Aryl Ether Bond Formation with PhenoFluor**

    OpenAIRE

    Shen, Xiao; Neumann, Constanze N.; Kleinlein, Claudia; Claudia, Nathaniel W.; Ritter, Tobias

    2015-01-01

    An alkyl aryl ether bond formation reaction between phenols and primary and secondary alcohols with PhenoFluor has been developed. The reaction features a broad substrate scope and tolerates many functional groups, and substrates that are challenging for more conventional ether bond forming processes may be coupled. A preliminary mechanistic study indicates reactivity distinct from conventional ether bond formation.

  14. 40 CFR 721.3550 - Dipropylene glycol dimethyl ether.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Dipropylene glycol dimethyl ether. 721... Substances § 721.3550 Dipropylene glycol dimethyl ether. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as dipropylene glycol dimethyl ether (PMN...

  15. 40 CFR 799.4440 - Triethylene glycol monomethyl ether.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 31 2010-07-01 2010-07-01 true Triethylene glycol monomethyl ether... REQUIREMENTS Specific Chemical Test Rules § 799.4440 Triethylene glycol monomethyl ether. (a) Identification of test substance. (1) Triethylene glycol monomethyl ether (TGME, CAS No. 112-35-6) shall be tested...

  16. Synthesis and characterizations of electrospun sulfonated poly (ether ether ketone) SPEEK nanofiber membrane

    Science.gov (United States)

    Hasbullah, N.; Sekak, K. A.; Ibrahim, I.

    2016-07-01

    A novel electrospun polymer electrolyte membrane (PEM) based on Sulfonated Poly (ether ether ketone) were prepared and characterized. The poly (ether ether ketone) PEEK was sulfonated using concentrated sulfuric acid at room temperature for 60 hours reaction time. The degree sulfonation (DS) of the SPEEK are 58% was determined by H1 NMR using area under the peak of the hydrogen shielding at aromatic ring of the SPEEK. Then, the functional group of the SPEEK was determined using Fourier transfer infrared (FTIR) showed O-H vibration at 3433 cm-1 of the sulfonated group (SO2-OH). The effect of the solvent and polymer concentration toward the electrospinning process was investigated which, the DMAc has electrospun ability compared to the DMSO. While, at 20 wt.% of the polymer concentration able to form a fine and uniform nanofiber, this was confirmed by FESEM that shown electrospun fiber mat SPEEK surface at nano scale diameter.

  17. Polyimides Containing Carbonyl and Ether Connecting Groups

    Science.gov (United States)

    Hergenrother, Paul M.; Havens, Stephen J.

    1987-01-01

    Semicrystallinity gives rise to tough, solvent-resistant polymers. New polyimides prepared from reaction of aromatic dianhydrides with new diamines containing carbonyl and ether connecting groups between aromatic rings. Damines prepared from reaction of 4-aminophenol with activated aromatic difluoro compounds in presence of potassium carbonate. These types of polymers have potential applications in molded products, films, adhesives, and composites.

  18. POLYBROMINATED DIPHENYL ETHERS IN SOUTHERN MISSISSIPPI CATFISH

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in a wide variety of consumer products. Concerns surrounding these compounds are primarily due do their ubiquitous presence in the environment as well as in human tissue, such as milk, coupled with evidence indi...

  19. Radiation-induced cationic curing of vinyl ethers

    International Nuclear Information System (INIS)

    Recently there has been an increasing interest in nonacrylate radiation-curable coatings. Vinyl ethers are particularly reactive under cationic polymerization reaction conditions. The high efficiency of the photoacid initiators combined with the high reactivity of vinyl ether monomers makes this a potentially very useful system. This chapter discusses the preparation of vinyl ethers, introduces vinyl ether-functional monomers and oligomers, describes radiation-induced cationic polymerization of vinyl ethers, and discusses various coating systems. Throughout the chapter, an emphasis is placed on radiation-curable coating applications. 64 refs., 5 figs., 11 tabs

  20. Impaired neurotransmission in ether lipid-deficient nerve terminals

    Science.gov (United States)

    Brodde, Alexander; Teigler, Andre; Brugger, Britta; Lehmann, Wolf D.; Wieland, Felix; Berger, Johannes; Just, Wilhelm W.

    2016-01-01

    Isolated defects of ether lipid (EL) biosynthesis in humans cause rhizomelic chondrodysplasia punctata type 2 and type 3, serious peroxisomal disorders. Using a previously described mouse model [Rodemer, C., Thai, T.P., Brugger, B., Kaercher, T., Werner, H., Nave, K.A., Wieland, F., Gorgas, K., and Just, W.W. (2003) Inactivation of ether lipid biosynthesis causes male infertility, defects in eye development and optic nerve hypoplasia in mice. Hum. Mol. Genet., 12, 1881–1895], we investigated the effect of EL deficiency in isolated murine nerve terminals (synaptosomes) on the pre-synaptic release of the neurotransmitters (NTs) glutamate and acetylcholine. Both Ca2+-dependent exocytosis and Ca2+-independent efflux of the transmitters were affected. EL-deficient synaptosomes respire at a reduced rate and exhibit a lowered adenosin-5′-triphosphate/adenosine diphosphate (ATP/ADP) ratio. Consequently, ATP-driven processes, such as synaptic vesicle cycling and maintenance of Na+, K+ and Ca2+ homeostasis, might be disturbed. Analyzing reactive oxygen species in EL-deficient neural and non-neural tissues revealed that plasmalogens (PLs), the most abundant EL species in mammalian central nervous system, considerably contribute to the generation of the lipid peroxidation product malondialdehyde. Although EL-deficient tissue contains less lipid peroxidation products, fibroblasts lacking ELs are more susceptible to induced oxidative stress. In summary, these results suggest that due to the reduced energy state of EL-deficient tissue, the Ca2+-independent efflux of NTs increases while the Ca2+-dependent release declines. Furthermore, lack of PLs is mainly compensated for by an increase in the concentration of phosphatidylethanolamine and results in a significantly lowered level of lipid peroxidation products in the brain cortex and cerebellum. PMID:22403185

  1. Evaluation of crystallization kinetics of poly (ether-ketone-ketone) and poly (ether-ether-ketone) by DSC

    OpenAIRE

    Gibran da Cunha Vasconcelos; Rogerio Lago Mazur; Edson Cocchieri Botelho; Mirabel Cerqueira Rezende; Michelle Leali Costa

    2010-01-01

    The poly (aryl ether ketones) are used as matrices in advanced composites with high performance due to its high thermal stability, excellent environmental performance and superior mechanical properties. Most of the physical, mechanical and thermodynamic properties of semi-crystalline polymers depend on the degree of crystallinity and morphology of the crystalline regions. Thus, a study on the crystallization process promotes a good prediction of how the manufacturing parameters affect the dev...

  2. Emergent gravity and ether-drift experiments

    CERN Document Server

    Consoli, M

    2009-01-01

    In principle, ether-drift experiments could distinguish phenomenologically emergent-gravity approaches, where an effective curvature emerges from hydrodynamic distortions of the same physical, flat-space vacuum, from the more conventional scenario where curvature is considered a fundamental property of space-time down to extremely small length scales and the speed of light represents a universal constant. From an experimental point of view, in this particular context, besides time modulations that might be induced by the Earth's rotation (and its orbital revolution), one should also consider the possibility of random fluctuations of the signal. These might reflect the stochastic nature of the underlying 'quantum ether' and be erroneously interpreted as mere instrumental noise. To test the present interpretation, we have extracted the mean amplitude of the signal from various experiments with different systematics, operating both at room temperature and in the cryogenic regime. They all give the same consisten...

  3. Synthesis of New Liquid Crystalline Diglycidyl Ethers

    Directory of Open Access Journals (Sweden)

    Issam Ahmed Mohammed

    2012-01-01

    Full Text Available The phenolic Schiff bases I–VI were synthesized by condensation reactions between various diamines, namely o-dianisidine, o-tolidine and ethylenediamine with vanillin or p-hydroxybenzaldehyde and subsequent reactions between these phenolic Schiff bases and epichlorohydrin to produce new diglycidyl ethers Ia–VIa. The structures of these compounds were confirmed by CHN, FT-IR, 1H-NMR, and 13C-NMR spectroscopy. Their thermotropic liquid crystalline behavior was studied using differential scanning calorimetry (DSC and polarizing optical microscopy (POM. All the diglycidyl ethers prepared exhibit nematic mesophases, except for Va and VIa, which did not show any transition mesophases, but simply flow to liquids.

  4. Synthesis of New Liquid Crystalline Diglycidyl Ethers

    OpenAIRE

    Issam Ahmed Mohammed; Rashidah Mohamed Hamidi

    2012-01-01

    The phenolic Schiff bases I–VI were synthesized by condensation reactions between various diamines, namely o-dianisidine, o-tolidine and ethylenediamine with vanillin or p-hydroxybenzaldehyde and subsequent reactions between these phenolic Schiff bases and epichlorohydrin to produce new diglycidyl ethers Ia–VIa. The structures of these compounds were confirmed by CHN, FT-IR, 1H-NMR, and 13C-NMR spectroscopy. Their thermotropic liquid crystalline behavior was studied using differential scannin...

  5. Ether bridge formation in loline alkaloid biosynthesis

    OpenAIRE

    Pan, Juan; Bhardwaj, Minakshi; Faulkner, Jerome R.; Nagabhyru, Padmaja; Charlton, Nikki D.; Higashi, Richard M.; Miller, Anne-Frances; Young, Carolyn A; Grossman, Robert B.; Schardl, Christopher L

    2013-01-01

    Lolines are potent insecticidal agents produced by endophytic fungi of cool-season grasses. These alkaloids are composed of a pyrrolizidine ring system and an uncommon ether bridge linking carbons 2 and 7. Previous results indicated that 1-aminopyrrolizidine was a pathway intermediate. We used RNA interference to knock down expression of lolO, resulting in the accumulation of a novel alkaloid identified as exo-1-acetamidopyrrolizidine based on high-resolution MS and NMR. Genomes of endophytes...

  6. Fluoroalkylation of aryl ether perfluorocyclobutyl polymers

    OpenAIRE

    Ligon, Clark; Ameduri, Bruno; Boutevin, Bernard; Smith, Dennis

    2008-01-01

    Post functionalization of aryl ether perfluorocyclobutyl (PFCB) polymers with fluoroalkyl side chains was accomplished with Umemoto's FITS reagents. The fluoroalkylated PFCB polymers (20 % functionalized) showed increases in both hydrophobicity and oleophobicity. Static contact angle for hexadecane was increased after fluoroalkylation from 0° to greater than 30° for the two PFCB polymers tested. Increased oil repellency makes these materials potential candidates for various coatings applicati...

  7. Model for Photodegradation of Polybrominated Diphenyl Ethers

    Czech Academy of Sciences Publication Activity Database

    Veselý, M.; Vajglová, Zuzana; Kotas, Petr; Křišťál, Jiří; Ponec, Robert; Jiřičný, Vladimír

    2015-01-01

    Roč. 22, č. 7 (2015), s. 4949-4963. ISSN 0944-1344 R&D Projects: GA ČR GA104/09/0880; GA ČR(CZ) GAP105/12/0664 Institutional support: RVO:67985858 ; RVO:67179843 Keywords : polybrominated diphenyl ethers * photodegradation model * quantum chemical calculation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.828, year: 2014

  8. Catalytic intermolecular hydroamination of vinyl ethers

    OpenAIRE

    Pahadi, Nirmal K.; Tunge, Jon A.

    2009-01-01

    This manuscript details the development of a palladium-catalyzed hydroamination of vinyl ethers. It is proposed that palladium catalyzes the hydroamination via Bronsted base catalysis, where palladium is protonated by the relatively acidic sulfonamide to generate a palladium hydride as well as the active anionic sulfonamide nucleophile. Thus, this process is distinct from known palladium-catalyzed hydroaminations of styrene derivatives that utilize less acidic amines.

  9. Poly(Arylene Ether Imidazole) Surface Films

    Science.gov (United States)

    Connell, John W.; Towell, Timothy W.; Tompkins, Stephen S.

    1993-01-01

    Films adhere well to some substrates, provide smooth surfaces, and facilitate release from molds. Thin films of thermoplastic poly(arylene ether imidazole)s (PAEI's) particularly suitable for use as surface modifiers for graphite/epoxy or graphite/bismaleimide composite panels. Molecule of PAEI includes imidazole groups along its backbone that co-cure with epoxies or bismaleimides during processing. Films thermally stable and resistant to bombardment by energetic electrons.

  10. The solubility and environmental characteristics of diesel ethers

    International Nuclear Information System (INIS)

    Concern over diesel particulate emissions has been ongoing for the past 2 decades, and a number of agencies have shown that adding ethers to diesel engines can reduce these particulates. However, the exact mechanism is not known. Methyl tert-butyl ether (MTBE) has been used for several years to improve the performance of gasoline engines. MTBE is very soluble in water and leaches out of the gasoline and into groundwater very easily. MTBE is being phased out due to this problem. This paper presented the results of a project initiated to evaluate candidate ethers for their solubility in water as well as other environmental characteristics. The ethers may also have the potential for reducing the emissions from diesel engines. Thirty-four ethers were tested for solubility, aquatic toxicity and biological oxygen demand. The tests were conducted due to concerns that MTBE has been shown to cause contamination as a result of its high solubility. The study focused on screening potential diesel ethers for a variety of acceptability criteria such as solubility, aquatic toxicity and degradation potential. A review of measuring methods, materials and instrumentation procedures was presented, along with solubility measurements. The stoichiometry and physical properties of petroleum ethers were also provided as well as test procedures for aquatic toxicity and microtox. A generalized property prediction model was presented. It was concluded that the properties, toxicity and degradation of the ethers vary widely. Solubility correlates with the structure of the ethers: di and tri-ethers are very soluble and any methyl ether also has high solubility. Biochemical oxygen testing of all tested ethers was low, indicating a low breakdown with typical bacterial cultures. The aquatic toxicity of the ethers is variable and correlates inversely with the solubility. The higher the solubility, the lower the toxicity. 24 refs., 10 tabs

  11. Nikola Tesla, the Ether and his Telautomaton

    Science.gov (United States)

    Milar, Kendall

    2014-03-01

    In the nineteenth century physicists' understanding of the ether changed dramatically. New developments in thermodynamics, energy physics, and electricity and magnetism dictated new properties of the ether. These have traditionally been examined from the perspective of the scientists re-conceptualizing the ether. However Nikola Tesla, a prolific inventor and writer, presents a different picture of nineteenth century physics. Alongside the displays that showcased his inventions he presented alternative interpretations of physical, physiological and even psychical research. This is particularly evident in his telautomaton, a radio remote controlled boat. This invention and Tesla's descriptions of it showcase some of his novel interpretations of physical theories. He offered a perspective on nineteenth century physics that focused on practical application instead of experiment. Sometimes the understanding of physical theories that Tesla reached was counterproductive to his own inventive work; other times he offered new insights. Tesla's utilitarian interpretation of physical theories suggests a more scientifically curious and invested inventor than previously described and a connection between the scientific and inventive communities.

  12. Alkyl aryl ethers in lignite solubilization

    Energy Technology Data Exchange (ETDEWEB)

    Mustral, A.M.; Cebolla, V.L.; Gavilan, J.M.

    1985-03-01

    The FT-I.R. and /sup 1/H N.M.R. spectroscopic analyses of oils or maltenes from a Spanish lignite (Utrillas, Teruel), are reported. These oils were obtained by depolymerization with alkyl aromatic ethers (anisole, 3-methyl anisole and 1,3-dimethoxybenzene) catalyzed by Lewis acids ZnCl/sub 2/, AlCl/sub 3/, SbCl/sub 3/ and BF/sub 3/ (as boron trifluoride etherate), at atmospheric pressure and temperatures <220/sup 0/C. Bands due to aromatic ethers in the I.R. and N.M.R. spectra of the oils obtained by depolymerization indicate solvent incorporation. Oils obtained by direct lignite extraction showed 25% aromatic H and some H /sub i/ (approx. = 3%) without OH groups. These appeared in some oils obtained by depolymerization with AlCl/sub 3/ and were due to secondary reactions with the aromatic extract. Oils derived from processes with good yields showed increases in aromaticity. The extent of substitution of aromatic rings in oils obtained by depolymerization was less than for oils directly extracted. All the oils studied show a low degree of condensation.

  13. Novel Finding of Widespread Occurrence and Accumulation of Bisphenol A Diglycidyl Ethers (BADGEs) and Novolac Glycidyl Ethers (NOGEs) in Marine Mammals from the United States Coastal Waters.

    Science.gov (United States)

    Xue, Jingchuan; Kannan, Kurunthachalam

    2016-02-16

    Bisphenol A diglycidyl ether (BADGE)- and bisphenol F diglycidyl ether (BFDGE)-based epoxy resins have a broad range of applications, including serving as inner coatings of food and beverage cans and as protective coatings in marine construction. Prior to this study, no studies had examined the occurrence and bioaccumulation of BADGEs or BFDGEs in aquatic organisms. In this study, BADGE, BFDGE, and nine of their derivatives were determined in 121 tissue (liver, kidney, blubber, and brain) samples from eight species of marine mammals collected from the U.S. coastal waters of Florida, California, Washington, and Alaska. BADGE·2HCl was the predominant compound found in the majority (78.5%) of the marine mammal tissues analyzed, at concentrations of up to 2950 ng/g (wet weight (wt)) found in the liver of a sea otter from Kachemak Bay, Alaska. The measured concentrations of BADGE·2HCl in marine mammals were on the order of hundreds of nanograms per gram tissue, which are some of the highest concentrations ever reported for this compound in biota. Males contained greater concentrations of BADGE·2HCl than did females. BADGE·2HCl also was found in the brain tissues of sea otters. Trace levels of BADGE·2HCl were found in the livers of polar bears from Alaska, which suggested that BADGEs are widely distributed in the oceanic environment. PMID:26800265

  14. Brain Basics

    Medline Plus

    Full Text Available ... News About Us Home > Health & Education > Educational Resources Brain Basics Introduction The Growing Brain The Working Brain ... to mental disorders, such as depression. The Growing Brain Inside the Brain: Neurons & Neural Circuits Neurons are ...

  15. Brain Basics

    Science.gov (United States)

    ... News About Us Home > Health & Education > Educational Resources Brain Basics Introduction The Growing Brain The Working Brain ... to mental disorders, such as depression. The Growing Brain Inside the Brain: Neurons & Neural Circuits Neurons are ...

  16. Brain Basics

    Medline Plus

    Full Text Available ... Brain Basics provides information on how the brain works, how mental illnesses are disorders of the brain, ... learning more about how the brain grows and works in healthy people, and how normal brain development ...

  17. Human ether-à-go-go gene potassium channels are regulated by EGFR tyrosine kinase

    OpenAIRE

    Li, GR; Wu, W.; Dong, MQ; Wu, XG; Sun, HY; Tse, HF; Lau, CP

    2011-01-01

    Human ether á-go-go gene potassium channels (hEAG1 or Kv10.1) are expressed in brain and various human cancers and play a role in neuronal excitement and tumor progression. However, the functional regulation of hEAG channels by signal transduction is not fully understood. The present study was therefore designed to investigate whether hEAG1 channels are regulated by protein tyrosine kinases (PTKs) in HEK 293 cells stably expressing hEAG1 gene using whole-cell patch voltage-clamp, immunoprecip...

  18. Electroless nickel-phosphorus coating on poly (ether ether ketone)/carbon nanotubes composite

    Science.gov (United States)

    Zhai, Tong; Di, Lizhi; Yang, De'an

    2014-05-01

    In order to improve electromagnetic shielding property of poly (ether ether ketone)/carbon nanotubes composite, a nickel-phosphorus coating was covered on the composite by electroless plating. The morphologies of the substrates and the coatings were characterized by SEM. XPS was performed to analyze the surface composition and chemical states before and after chemical etching. The results showed that lots of microscopic holes appeared and evenly distributed on the surface, and the concentration of hydrophilic groups on the surface increased after the composite was etched. Thermal shock test showed that the adhesive strength between the coating and the composite was good.

  19. Azidated Ether-Butadiene-Ether Block Copolymers as Binders for Solid Propellants

    Science.gov (United States)

    Cappello, Miriam; Lamia, Pietro; Mura, Claudio; Polacco, Giovanni; Filippi, Sara

    2016-07-01

    Polymeric binders for solid propellants are usually based on hydroxyl-terminated polybutadiene (HTPB), which does not contribute to the overall energy output. Azidic polyethers represent an interesting alternative but may have poorer mechanical properties. Polybutadiene-polyether copolymers may combine the advantages of both. Four different ether-butadiene-ether triblock copolymers were prepared and azidated starting from halogenated and/or tosylated monomers using HTPB as initiator. The presence of the butadiene block complicates the azidation step and reduces the storage stability of the azidic polymer. Nevertheless, the procedure allows modifying the binder properties by varying the type and lengths of the energetic blocks.

  20. The First Example of Cation Radical Induced Ether Cleavage of Benzyl Phenyl Ether

    International Nuclear Information System (INIS)

    A thermally stable benzyl phenyl ether has been shown to cleavage under mild conditions. The new reaction described herein further expands the chemistry of the ether cleavage by cation radicals. Over the last several years, our lab has discovered cation radical-induced oxidative C-O bond cleavages such as carbonates (eq 1), carbamates (eq 2), peroxides (eq 3), and alcohols (eq 4), where R is either tert-butyl or benzyl. It was recognized from those reactions that carbocationic chemistry with C-O bond cleavages was predominant, with a 2:1 stoichiometry of Th+·:oxidized molecules

  1. Absorption of some glycol ethers through human skin in vitro.

    OpenAIRE

    Dugard, P H; M. Walker; Mawdsley, S J; Scott, R.C.

    1984-01-01

    To assist evaluation of the hazards of skin contact with selected undiluted glycol ethers, their absorption across isolated human abdominal epidermis was measured in vitro. Epidermal membranes were set up in glass diffusion cells and, following an initial determination of permeability to tritiated water, excess undiluted glycol ether was applied to the outer surface for 8 hr. The appearance of glycol ether in an aqueous "receptor" phase bathing the underside of the epidermis was quantified by...

  2. SYNTHESIS OF POLY ( ETHER-URETHANE) CONTAINING PENDANT AMINO GROUP

    Institute of Scientific and Technical Information of China (English)

    WU Jinhuang; SUN Yanhui; FENG Xinde

    1989-01-01

    This paper is concerned with the synthesis of poly (ether-urethane) with pendant amino groups. The copolyether produced by ring opening copolymerization of tetrahydrofuran and epibromohydrin was treated with sodium azide in dimethylformamide to form azido substituted copolyether. The poly (ether-urethane) made from it was subjected to reduction reaction to convert azido group to amino group. The stress-strain behavior and dynamic-mechanical properties of poly (ether-urethane) containing pendant amino groups were studied.

  3. A mechanistic view of polybrominated diphenyl ether (PBDE) developmental neurotoxicity.

    Science.gov (United States)

    Costa, Lucio G; de Laat, Rian; Tagliaferri, Sara; Pellacani, Claudia

    2014-10-15

    Polybrominated diphenyl ethers (PBDEs), extensively used in the past few decades as flame retardants in a variety of consumer products, have become world-wide persistent environmental pollutants. Levels in North America are usually higher than those in Europe and Asia, and body burden is 3-to-9-fold higher in infants and toddlers than in adults. The latter has raised concern for potential developmental toxicity and neurotoxicity of PBDEs. Experimental studies in animals and epidemiological observations in humans suggest that PBDEs may be developmental neurotoxicants. Pre- and/or post-natal exposure to PBDEs may cause long-lasting behavioral abnormalities, particularly in the domains of motor activity and cognition. The mechanisms underlying the developmental neurotoxic effects of PBDEs are not known, though several hypotheses have been put forward. One general mode of action relates to the ability of PBDEs to impair thyroid hormone homeostasis, thus indirectly affecting the developing brain. An alternative or additional mode of action involves a direct effect of PBDEs on nervous system cells; PBDEs can cause oxidative stress-related damage (DNA damage, mitochondrial dysfunction, apoptosis), and interfere with signal transduction (particularly calcium signaling), and with neurotransmitter systems. Important issues such as bioavailability and metabolism of PBDEs, extrapolation of results to low level of exposures, and the potential effects of interactions among PBDE congeners and between PBDEs and other contaminants also need to be taken into account. PMID:24270005

  4. Brain herniation

    Science.gov (United States)

    ... herniation; Uncal herniation; Subfalcine herniation; Tonsillar herniation; Herniation - brain ... Brain herniation occurs when something inside the skull produces pressure that moves brain tissues. This is most ...

  5. Lithiated and sulphonated poly(ether ether ketone) solid state electrolyte films for supercapacitors

    International Nuclear Information System (INIS)

    Poly(ether ether ketone) (PEEK) films have been synthesised and used as solid-state electrolytes for supercapacitors. In order to increase their ion conductivity, the PEEK films were sulphonated by sulphuric acid, and various amounts of LiClO4 were added. The solid-state electrolyte films were characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. The ionic conductivities of the electrolyte films were analysed by performing electrochemical impedance spectroscopy. The obtained electrolyte films can be sandwiched or directly coated on activated carbon electrodes to form solid-state supercapacitors. The electrochemical characteristics of these supercapacitors were investigated by performing cyclic voltammetry and charge–discharge tests. Under an optimal content of LiClO4, the supercapacitor can provide a capacitance as high as 190 F/g. After 1000 cycles, the supercapacitors show almost no capacitance fading, indicating high stability of the solid-state electrolyte films. - Highlights: • Poly(ether ether ketone) (PEEK) films have been used as solid-state electrolytes. • LiClO4 addition can efficiently improve the ionic conductivity. • Supercapacitors using PEEK electrolyte films deliver high capacitance

  6. Unprecedented reactions: from epichlorohydrin to epoxyglycidyl substituted divinyl ether and its conversion into epoxyglycidyl propargyl ether

    Science.gov (United States)

    Yao, Yiwu; Li, Zheng; Qiu, Yatao; Bai, Jinhong; Su, Jinyue; Zhang, Dayong; Jiang, Sheng

    2015-09-01

    The reaction of epichlorohydrin with concentrated sodium hydroxide in hexane under phase transfer conditions has surprisingly led to the formation of the symmetrical di(3-epoxyglycidyl-1-propenyl) ether 1 which contains both nucleophilic and electrophilic moieties. When it was reacted with n-butyllithium, intermediate 1 once again surprisingly generated epoxyglycidyl propargyl ether, which was further reacted in situ with a variety of benzaldehydes to furnish the corresponding substituted propargylic alcohols in good yields. While the reaction is operationally simple, it provides a powerful method for the synthesis of the important products from commodity materials such as epichlorohydrin. Moreover, these reactions may have revealed that some fundamental properties of the hydroxide anion in those once thought straightforward reactions are not well understood. A careful analysis of the experimental data suggests that an unprecedented concerted elimination of the epoxyglycidyl ether with sodium hydroxide may be operative and an alpha deprotonation followed by alpha elimination of the di(3-epoxyglycidyl-1-propenyl) ether with alkyllithium may have been involved.

  7. Lithiated and sulphonated poly(ether ether ketone) solid state electrolyte films for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, K.-F.; Su, S.-H., E-mail: minimono42@gmail.com

    2013-10-01

    Poly(ether ether ketone) (PEEK) films have been synthesised and used as solid-state electrolytes for supercapacitors. In order to increase their ion conductivity, the PEEK films were sulphonated by sulphuric acid, and various amounts of LiClO{sub 4} were added. The solid-state electrolyte films were characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. The ionic conductivities of the electrolyte films were analysed by performing electrochemical impedance spectroscopy. The obtained electrolyte films can be sandwiched or directly coated on activated carbon electrodes to form solid-state supercapacitors. The electrochemical characteristics of these supercapacitors were investigated by performing cyclic voltammetry and charge–discharge tests. Under an optimal content of LiClO{sub 4}, the supercapacitor can provide a capacitance as high as 190 F/g. After 1000 cycles, the supercapacitors show almost no capacitance fading, indicating high stability of the solid-state electrolyte films. - Highlights: • Poly(ether ether ketone) (PEEK) films have been used as solid-state electrolytes. • LiClO4 addition can efficiently improve the ionic conductivity. • Supercapacitors using PEEK electrolyte films deliver high capacitance.

  8. All solid supercapacitor based on polyaniline and crosslinked sulfonated poly[ether ether ketone

    International Nuclear Information System (INIS)

    All solid supercapacitor based on polyaniline (PANI) and crosslinked sulfonated poly[ether ether ketone] (XSPEEK,) is reported in this paper. The crosslinker used for sulfonated poly[ether ether ketone] (SPEEK) is 1,4-bis(hydroxymethyl) benzene. The XSPEEK is used as both solid electrolyte and separator membrane. Supercapacitors are fabricated using various PANI/XSPEEK weight ratios. These are characterized by cyclic voltammetry and galvanostatic charge-discharge studies. The supercapacitor with PANI/XSPEEK weight ratio 1:0.5, exhibit a specific capacitance of 480 F g-1 of PANI. To the best of authors' knowledge, the value reported here is the highest for a supercapacitor based on a proton conducting solid polymer electrolyte and PANI. Detailed electrochemical impedance spectroscopy analysis is carried out. The analysis shows that the complex capacitance of the supercapacitor depends on the XSPEEK content. The time constant (t0), derived from the imaginary part of complex capacitance decreases with increase in the XSPEEK content in the supercapacitor. Cycle life characteristics of the supercapacitor show a decrease in specific capacitance during initial cycles and get stabilized during later cycles.

  9. Copper Promoted Synthesis of Diaryl Ethers

    OpenAIRE

    Ghosh, Rajshekhar; Samuelson, Ashoka G

    2004-01-01

    An efficient protocol using copper based reagents for the coupling of aryl halides with phenols to generate diaryl ethers is described. Acopper( I) complex, [ Cu( CH3CN) (4)] ClO4, or the readily available copper( II) source, CuCO3 . Cu( OH) (2) . H2O ( in combination with potassium phosphate), can be used. Aryl halides and phenols with different steric and electronic demands have been used to assess the efficiency of the procedure. The latter source of copper gives better yields under all co...

  10. Brain Basics

    Medline Plus

    Full Text Available ... Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take pictures of the brain's structure, studies show that brain growth in children with autism ...

  11. Application of simplified PC-SAFT to glycol ethers

    DEFF Research Database (Denmark)

    Avlund, Ane Søgaard; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2012-01-01

    The simplified PC-SAFT (sPC-SAFT) equation of state is applied for binary glycol ether-containing mixtures, and it is investigated how the results are influenced by inclusion of intramolecular association in the association theory. Three different glycol ethers are examined: 2-methoxyethanol, 2...

  12. Synthesis and Biophysical Characterization of Chlorambucil Anticancer Ether Lipid Prodrugs

    DEFF Research Database (Denmark)

    Pedersen, Palle Jacob; Christensen, Mikkel Stochkendahl; Ruysschaert, Tristan;

    2009-01-01

    The synthesis and biophysical characterization of four prodrug ether phospholipid conjugates are described. The lipids are prepared from the anticancer drug chlorambucil and have C16 and C18 ether chains with phosphatidylcholine or phosphatidylglycerol headgroups. All four prodrugs have the abili...

  13. Congenital malformations and maternal occupational exposure to glycol ethers

    NARCIS (Netherlands)

    Cordier, S; Bergeret, A; Goujard, J; Ha, MC; Ayme, S; Calzolari, E; DeWalle, HEK; KnillJones, R; Candela, S; Dale, [No Value; Dananche, B; deVigan, C; Fevotte, J; Kiel, G; Mandereau, L

    1997-01-01

    Glycol ethers are found in a wide range of domestic and industrial products, many of which are used in women's work environments. Motivated by concern about their potential reproductive toxicity, we have evaluated the risk of congenital malformations related to glycol ether exposure during preg nanc

  14. Biosynthesis of archaeal membrane ether lipids.

    Science.gov (United States)

    Jain, Samta; Caforio, Antonella; Driessen, Arnold J M

    2014-01-01

    A vital function of the cell membrane in all living organism is to maintain the membrane permeability barrier and fluidity. The composition of the phospholipid bilayer is distinct in archaea when compared to bacteria and eukarya. In archaea, isoprenoid hydrocarbon side chains are linked via an ether bond to the sn-glycerol-1-phosphate backbone. In bacteria and eukarya on the other hand, fatty acid side chains are linked via an ester bond to the sn-glycerol-3-phosphate backbone. The polar head groups are globally shared in the three domains of life. The unique membrane lipids of archaea have been implicated not only in the survival and adaptation of the organisms to extreme environments but also to form the basis of the membrane composition of the last universal common ancestor (LUCA). In nature, a diverse range of archaeal lipids is found, the most common are the diether (or archaeol) and the tetraether (or caldarchaeol) lipids that form a monolayer. Variations in chain length, cyclization and other modifications lead to diversification of these lipids. The biosynthesis of these lipids is not yet well understood however progress in the last decade has led to a comprehensive understanding of the biosynthesis of archaeol. This review describes the current knowledge of the biosynthetic pathway of archaeal ether lipids; insights on the stability and robustness of archaeal lipid membranes; and evolutionary aspects of the lipid divide and the LUCA. It examines recent advances made in the field of pathway reconstruction in bacteria. PMID:25505460

  15. Process for producing cyclic ethers from lactones

    International Nuclear Information System (INIS)

    Cyclic ethers are produced from lactones by a process which comprises directly synthesizing cyclic ethers by the reduction of the carbonyl radicals of lactones with trichlorosilane either by the action of ionizing, visible, or ultraviolet radiations, or alternately in the presence of free radical initiators. For instance, gamma-butyl lactone mixed with trichlorosilane yields 82% of tetrahydrofuran when only irradiated with gamma-rays, whereas it yields 94% of tetrahydrofuran when exposed to ultraviolet radiations in the presence of a little amount of peroxide. Such a high yield reveals that the ring opening reaction and the ring closing reaction are not continuous, but are chain reactions in which carbonyl radicals are selectively reduced to methylene radicals without cutting the backbone structure. In one embodiment, lactone and trichlorosilane were de-aired by the vacuum refrigeration method respectively, and after being mixed in the proportion of 4:1 in a tube they were exposed to gamma-rays from a Co-60 source at room temperature at a dose rate of 3 x 105 rad/hr. In another embodiment, a de-aired mixture of lactone and ditertiary butyl peroxide with de-aired trichlorosilane in a tube were exposed to a high voltage mercury lamp for 2 hours. Ninety four percent of gamma-tetrahydrofuran, 92.2% of valerolactone tetrahydropyran or 95.7% of caprolactone hexamethylene oxide were obtained. (Iwakiri, K.)

  16. Levels and distribution of polybrominated diphenyl ethers in various tissues of birds of prey

    International Nuclear Information System (INIS)

    In the present study, concentrations and tissue distribution of polybrominated diphenyl ethers (PBDEs; IUPAC nos. 28, 47, 99, 100, 153, 154, 183, and 209) were examined in brain, adipose tissue, liver, muscle, and serum of birds of prey. Median ΣPBDE levels (BDE 28-183) in the tissues of sparrowhawks ranged from 360 to 1900 ng/g lipid weight (lw), which was in general one order of magnitude higher than in the tissues of common buzzards (26-130 ng/g lw). There were no differences in PBDE congener patterns between the various tissues within individuals of a certain species. Inter-species differences in PBDE patterns and in particular the percentage of BDE 99, 100 and 153 were, however, pronounced between sparrowhawk and common buzzard. BDE 209 was detected in nearly all serum and in some liver samples, but not in any other tissues. This observation suggests that exposure to BDE 209 is low or that this congener is poorly accumulated. Passive (lipid content related) diffusion could not completely describe the PBDE tissue distribution, e.g. the lowest PBDE-load was measured in brain, a fairly lipid rich tissue. - Distribution of polybrominated diphenyl ethers in birds of prey is tissue dependent

  17. The effects of water on the morphology and the swelling behavior of sulfonated poly(ether ether ketone) films

    NARCIS (Netherlands)

    Koziara, B.T.; Akkilic, N.; Nijmeijer, K.; Benes, N.E.

    2016-01-01

    Thin sulfonated poly(ether ether ketone) films swell excessively in water. The extent of water-induced swelling is shown to be correlated with the optical anisotropy of the films, due to two distinct phenomena. Firstly, the optical anisotropy is directly related to the amount of water taken up from

  18. Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,

    Directory of Open Access Journals (Sweden)

    Mathew Obichukwu EDOGA

    2006-07-01

    Full Text Available First, phenol - formaldehyde (PF and urea - formaldehyde (UFII resins were separately conventionally prepared in our laboratory. Also, UF resin synthesized from the acid modified synthesis procedure was synthesized in a purely acid medium of pH 1.0, FU molar ratio of 1.0 and at 50oC (one-stage acid modified-synthesis procedure. Subsequently, the UF resin II was modified during synthesis by incorporating ethylated urea-ether (EUER (i.e. UFIII and glycerol (GLYC (i.e. UFV cured with and without acid curing agent. The structural and physicochemical analyses of the various resin samples were carried out.The results showed that the unmodified UF resin (UF II synthesized in acid medium of pH 1.0, F/U molar ratio 1.0, and at 50oC, cured in absence of acid curing catalyst, showed features in their spectra which are consistent with a tri-, and/or tetra-substituted urea in the reaction to give a 3 - dimensional network cured UF resin. Modification of the UF resin(UF II with ethylated urea-ether and glycerol to produce UF resins III and respectively V prominently increased the absorbance of methylene and ether groups in the spectra which are consistent with increased hydrophobicity and improved hydrolytic stability. For the conventional UF resin (UF I, the only clear distinction between spectra for the UF resin II and UF resins (III/V is the presence of diminished peaks for methylene groups at 2.2 ppm. The relationship between the logarithmic viscosity of cured PF resin with time showed continuos dependence of viscosity with time during cure up to 70 minutes. Similar trends were shown by UF resins (III/V, cured in absence of acid catalyst. In contrast, the conventional UF resins I and UF IV (i.e. UF II cured with NH4CL showed abrupt discontinuity in viscosity with time just after about 20 minutes of cure.

  19. Sulfonated poly(tetramethydiphenyl ether ether ketone) membranes for vanadium redox flow battery application

    Energy Technology Data Exchange (ETDEWEB)

    Mai, Zhensheng; Bi, Cheng; Dai, Hua [PEMFC Key Materials and Technology Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Huamin; Li, Xianfeng [PEMFC Key Materials and Technology Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023 (China)

    2011-01-01

    Sulfonated poly(tetramethydiphenyl ether ether ketone) (SPEEK) with various degree of sulfonation is prepared and first used as ion exchange membrane for vanadium redox flow battery (VRB) application. The vanadium ion permeability of SPEEK40 membrane is one order of magnitude lower than that of Nafion 115 membrane. The low cost SPEEK membranes exhibit a better performance than Nafion at the same operating condition. VRB single cells with SPEEK membranes show very high energy efficiency (>84%), comparable to that of the Nafion, but at much higher columbic efficiency (>97%). In the self-discharge test, the duration of the cell with the SPEEK membrane is two times longer than that with Nafion 115. The membrane keeps a stable performance after 80-cycles charge-discharge test. (author)

  20. Polymeric 32-channel arrayed waveguide grating multiplexer using fluorinated poly (ether ether ketone)

    Institute of Scientific and Technical Information of China (English)

    Fei Wang(王菲); Wei Sun(孙伟); Aize Li(李艾泽); Maobin Yi(衣茂斌); Zhenhua Jiang(姜振华); Daming Zhang(张大明)

    2004-01-01

    In wavelength division multiplexing (WDM) systems, an arrayed waveguide grating (AWG) multiplexer is a key component. A polymeric AWG multiplexer has recently attracted much attention due to its low cost processing and a potential of integration with other devices. Fluorinated poly (ether ether ketone)(FPEEK) is excellent material for fabrication of optical waveguides due to its low absorption loss at 1.55-μm wavelength and high thermal stability. A 32-channel AWG multiplexer has been designed based on the grating diffraction theory and fabricated using newly synthesized FPEEK. During the fabrication process of the Polymer/Si AWG device, spin coating, vaporizing, photolithographic patterning and reactive ion etching (RIE) are used. The AWG multiplexer measurement system is based on a tunable semiconductor laser, infrared camera and a Peltier-type heater. The device exhibits a wavelength channel spacing of 0.8nm and a center wavelength of 1548 nm in the room temperature.

  1. Poly (ether ether ketone) derivatives: Synthetic route and characterization of nitrated and sulfonated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Conceicao, T.F.; Bertolino, J.R. [Grupo de Estudo em Materiais Polimericos-Departamento de Quimica, Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil); Barra, G.M.O. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil); Pires, A.T.N. [Grupo de Estudo em Materiais Polimericos-Departamento de Quimica, Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil)], E-mail: alfredotiburcio@pq.cnpq.br

    2009-03-01

    Nitrated and sulfonated poly (ether ether ketone) [SNPEEK] samples were prepared through sulfonation of nitrated PEEK (NPEEK) at different temperatures resulting in polymers with distinct sulfonation degrees (SD). The sulfonation occurred preferentially in the hydroquinone segment even after 81% of this moiety had been nitrated. Sulfonation in the benzophenone moiety was achieved only in 16% of this segment at the reaction temperature of 80 deg. C. The substitution degree was obtained through the TG curves, and values were in agreement with {sup 1}H NMR data when SD is much higher as ND (nitration degree). The highest SD obtained was 72%. Membranes of the sulfonated and nitrated PEEK (SNPEEK) were prepared by casting and showed good ductility depending on the substitution degree, with proton conductivity in the order of 10{sup -2} S cm{sup -1}, an important characteristic in some applications, such as in fuel cells.

  2. Enhanced osteogenic activity of poly ether ether ketone using calcium plasma immersion ion implantation.

    Science.gov (United States)

    Lu, Tao; Qian, Shi; Meng, Fanhao; Ning, Congqin; Liu, Xuanyong

    2016-06-01

    As a promising implantable material, poly ether ether ketone (PEEK) possesses similar elastic modulus to that of cortical bones yet suffers from bio-inertness and poor osteogenic properties, which limits its application as orthopedic implants. In this work, calcium is introduced onto PEEK surface using calcium plasma immersion ion implantation (Ca-PIII). The results obtained from scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) confirm the modified layer with varying contents of calcium are formed on PEEK surfaces. Water contact angle measurements reveal the increasing hydrophobicity of both Ca-PIII treated surfaces. In vitro cell adhesion, viability assay, alkaline phosphatase activity and collagen secretion analyses disclose improved the adhesion, proliferation, and osteo-differentiation of rat bone mesenchymal stem cells (bMSCs) on Ca-PIII treated surfaces. The obtained results indicate that PEEK surface with enhanced osteogenic activity can be produced by calcium incorporation. PMID:26954085

  3. Effects of spinneret structure on poly-ether-ether-ketone fibers by screw extrusion

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xin-ying; YI Xiao-su; XU Zhong-bin; XU Ya-hong

    2005-01-01

    According to the characters of poly-ether-ether-ketone (PEEK) plastic, the spinnerets with three kinds of different structure were designed. The effects of spinneret structure on the melt spinning conditions, melt flow instability of the screw extrusion, and the performance of PEEK fibers were studied. The results show that the appropriate screw extrusion temperature is 370 -385℃. The PEEK fibers extruded using the spinnerets with L/D= 6,8 holes and 0.5 mm in diameter have better performances. The performances of PEEK fibers are related to the diameter of the spinneret hole. Increasing the L/D value of the spinnerets can not always improve the surface quality and the performances of PEEK fibers. The extrusion pressure is about 50% of that of the spinneret with 12 holes and 0.3 mm in diameter.

  4. Hydrophilization of Poly(ether ether ketone) Films by Surface-initiated Atom Transfer Radical Polymerization

    DEFF Research Database (Denmark)

    Fristrup, Charlotte Juel; Eskimergen, Rüya; Burkrinsky, J.T.;

    2008-01-01

    Poly(ether ether ketone) (PEEK) replaces aluminum and other metals in aerospace, electronics, medical, and automotive applications. Therefore, the demand for metallization of PEEK is continuously increasing. Metals seldom bond to a polymer without undergoing some chemical interaction - this is the......-modified PEEK using Surface-Initiated Atom Transfer Radical Polymerization (SI ATRP). Surface reduction of PEEK to form hydroxyl groups [1, 2, 3] was .performed prior to the attachment of 2-bromoisobutyrate initiating groups. Each modification step of PEEK as well as the polymer grafting was followed and...... mechanism leading to good adhesion. From the different types of bonding, the covalent bond at the polymer - metal interface is the strongest. In this work the surface ofPEEK is functionalized by covalently bounding of hydrophilic polymer brushes ofpoly(ethyleneglycol) methacrylate (PEGMA) from initiator...

  5. Modification of Poly(ether ether ketone Polymer for Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    Devesh Shukla

    2013-01-01

    Full Text Available Polyelectrolyte membrane (PEM is an important part of PEM fuel cell. Nafion is a commercially known membrane which gives the satisfactory result in PEM fuel cell operating at low temperature. Present research paper includes functionalization of Poly(ether ether ketone (PEEK polymer with phosphonic acid group. The functionalization was done with the help of nickel-based catalyst. Further, the polymer was characterized by the FTIR, EDAX, DSC, TGA, and 1H NMR, and it was found that PEEK polymer was functionalized with phosphonic acid group with good thermal stability in comparison to virgin PEEK. Finally, the thin films of functionalized polymer were prepared by solution casting method, and proton conductivity of film samples was measured by impedance spectra whose value was found satisfactory with good thermal stability in comparison to commercially available Nafion membrane.

  6. Poly(vinylbenzyl sulfonic acid)-grafted poly(ether ether ketone) membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Mi-Lim; Choi, Jisun; Woo, Hyun-Su; Kumar, Vinod; Sohn, Joon-Yong; Shin, Junhwa, E-mail: shinj@kaeri.re.kr

    2014-02-15

    Highlights: • PEEK-g-PVBSA, a polymer electrolyte membrane was prepared by a radiation grafting technique. • Poly(ether ether ketone) (PEEK), an aromatic hydrocarbon polymer was used as a grafting backbone film. • The water uptake, proton conductivity, and methanol permeability of the membranes were evaluated. • PEEK-g-PVBSA membranes show considerably lower methanol permeability compared to a Nafion membrane. -- Abstract: In this study, an aromatic hydrocarbon based polymer electrolyte membrane, poly(vinylbenzyl sulfonic acid)-grafted poly(ether ether ketone) (PEEK-g-PVBSA), has been prepared by the simultaneous irradiation grafting of vinylbenzyl chloride (VBC) monomer onto a PEEK film and subsequent sulfonation. Each chemical conversion was monitored by FT-IR and SEM–EDX instruments. The physicochemical properties including IEC, water uptake, proton conductivity, and methanol permeability of the prepared membranes were also investigated and found that the values of these properties increase with the increase of degree of grafting. It was observed that the IEC values of the prepared PEEK-g-PVBSA membranes with 32%, 58%, and 80% DOG values were 0.50, 1.05, and 1.22 meq/g while the water uptakes were 14%, 20%, and 21%, respectively. The proton conductivities (0.0272–0.0721 S/cm at 70 °C) were found to be somewhat lower than Nafion 212 (0.126 S/cm at 70 °C) at a relative humidity of 90%. However, the prepared membranes showed a considerably lower methanol permeability (0.61–1.92 × 10{sup −7} cm{sup 2}/s) compared to a Nafion 212 membrane (5.37 × 10{sup −7} cm{sup 2}/s)

  7. Mass transport of direct methanol fuel cell species in sulfonated poly(ether ether ketone) membranes

    International Nuclear Information System (INIS)

    Homogeneous membranes based on sulfonated poly(ether ether ketone) (sPEEK) with different sulfonation degrees (SD) were prepared and characterized. In order to perform a critical analysis of the SD effect on the polymer barrier and mass transport properties towards direct methanol fuel cell species, proton conductivity, water/methanol pervaporation and nitrogen/oxygen/carbon dioxide pressure rise method experiments are proposed. This procedure allows the evaluation of the individual permeability coefficients in hydrated sPEEK membranes with different sulfonation degrees. Nafion[reg] 112 was used as reference material. DMFC tests were also performed at 50 deg. C. It was observed that the proton conductivity and the permeability towards water, methanol, oxygen and carbon dioxide increase with the sPEEK sulfonation degree. In contrast, the SD seems to not affect the nitrogen permeability coefficient. In terms of selectivity, it was observed that the carbon dioxide/oxygen selectivity increases with the sPEEK SD. In contrast, the nitrogen/oxygen selectivity decreases. In terms of barrier properties for preventing the DMFC reactants loss, the polymer electrolyte membrane based on the sulfonated poly(ether ether ketone) with SD lower or equal to 71%, although having slightly lower proton conductivity, presented much better characteristics for fuel cell applications compared with the well known Nafion[reg] 112. In terms of the DMFC tests of the studied membranes at low temperature, the sPEEK membrane with SD = 71% showed to have similar performance, or even better, as that of Nafion[reg] 112. However, the highest DMFC overall efficiency was achieved using sPEEK membrane with SD = 52%

  8. Poly(vinylbenzyl sulfonic acid)-grafted poly(ether ether ketone) membranes

    International Nuclear Information System (INIS)

    Highlights: • PEEK-g-PVBSA, a polymer electrolyte membrane was prepared by a radiation grafting technique. • Poly(ether ether ketone) (PEEK), an aromatic hydrocarbon polymer was used as a grafting backbone film. • The water uptake, proton conductivity, and methanol permeability of the membranes were evaluated. • PEEK-g-PVBSA membranes show considerably lower methanol permeability compared to a Nafion membrane. -- Abstract: In this study, an aromatic hydrocarbon based polymer electrolyte membrane, poly(vinylbenzyl sulfonic acid)-grafted poly(ether ether ketone) (PEEK-g-PVBSA), has been prepared by the simultaneous irradiation grafting of vinylbenzyl chloride (VBC) monomer onto a PEEK film and subsequent sulfonation. Each chemical conversion was monitored by FT-IR and SEM–EDX instruments. The physicochemical properties including IEC, water uptake, proton conductivity, and methanol permeability of the prepared membranes were also investigated and found that the values of these properties increase with the increase of degree of grafting. It was observed that the IEC values of the prepared PEEK-g-PVBSA membranes with 32%, 58%, and 80% DOG values were 0.50, 1.05, and 1.22 meq/g while the water uptakes were 14%, 20%, and 21%, respectively. The proton conductivities (0.0272–0.0721 S/cm at 70 °C) were found to be somewhat lower than Nafion 212 (0.126 S/cm at 70 °C) at a relative humidity of 90%. However, the prepared membranes showed a considerably lower methanol permeability (0.61–1.92 × 10−7 cm2/s) compared to a Nafion 212 membrane (5.37 × 10−7 cm2/s)

  9. Microwave Spectrum of the Ethylmethyl Ether Molecule

    Directory of Open Access Journals (Sweden)

    Kojiro Takagi

    2003-01-01

    Full Text Available We have observed rotational transitions of ethylmethyl ether (CH3CH2OCH3 in the 24-110 GHz frequency range. We newly assigned the transitions of four Q-branch series for J=1-38 with Ka=0-5 and six R-branch series of b-type transitions for J=7-37 with Ka=0-3. All these assigned transitions were observed to be split into two or four components due to the internal rotations of the methyl groups. We analyzed the averaged frequencies of the split components on the basis of the Watson A-reduced Hamiltonian, neglecting the effect of the internal rotations. A total of 122 transitions were fitted to eight molecular parameters to a 1s standard deviation of 24 kHz. The parameters A, B, C and DJ were improved, and DJK, Dk, dJ and dK were determined for the first time.

  10. The Lubrication Qualities of Dimethyl Ether (DME)

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Sorenson, Spencer C; Jakobsen, J.

    2002-01-01

    Dimethyl Ether (DME) has been recognised as a clean alternative for diesel oil for some years now. Fuelling diesel engines with DME solves their two most significant problems: The emission of particulate matter is virtually eliminated and the level of NOx can be reduced considerably by exhaust gas...... the viscosity, which plays a major role in the hydrodynamic lubrication regime. The lubricity of DME has been established by the medium frequency pressurised reciprocating rig (MFPRR) to be very low compared to the one of diesel oil. But the DME film limits the wear extent significantly compared to...... the case of dry sliding. By mixing DME with additives, the lubricity level is easily raised even above the one of diesel oil. The viscosity of DME has been established by the volatile fuel viscometer (VFVM) to be as low as 0.185 cSt @ 25 oC. It is also shown that this viscosity cannot be raised...

  11. Acyclic archaebacterial ether lipids in swamp sediments

    Science.gov (United States)

    Pauly, George G.; Van Vleet, Edward S.

    1986-06-01

    Acyclic phytanyl diether glycerol and biphytanyl ether lipids have been quantified in two modern swamp sediment cores in concentrations ranging up to 360 μg/ml porewater. Methanogenic bacteria are the only known source organisms which can inhabit the swamp sediments. Variations in relative abundance between these lipids may reflect taxonomic changes in methanogen populations or the stage of growth. Maxima in methanogen lipid concentrations coincide with local maxima of 13C of organic matter, possibly the result of a pool effect on CO 2 or acetate. Methane production estimates calculated from lipid concentrations in swamp sediments range from 0.1 to 1.3 mmol cm -2 yr -1, values which are consistent with published methane fluxes.

  12. Development of specialty chemicals from dimethyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Tartamella, T.L.; Lee, S. [Univ. of Akron, OH (United States). Dept. of Chemical Engineering

    1996-12-31

    Dimethyl ether (DME) may be efficiently produced from coal-bases syngas in a high pressure, mechanically agitated slurry reactor. DME synthesis occurs in the liquid phase using a dual catalyst. By operating in a dual catalyst mode, DME may be converted from in-situ produced methanol resulting in higher methyl productivities and syngas conversions over methanol conversion alone. The feasibility of utilizing DME as a building block for more valuable specialty chemicals has been examined. A wide variety of petrochemicals may be produced from DME including light olefins, gasoline range hydrocarbons, oxygenates, and glycol precursors. These chemicals represent an important part of petroleum industries inventory of fine chemicals. Carbonylation, hydrocarbonylation, and oxidative dimerization are but a few of the reactions in which DME may undergo conversion. DME provides an additional route for the production of industrially important petrochemicals.

  13. Formulating liquid ethers for microtubular SOFCs

    Science.gov (United States)

    Kendall, Kevin; Slinn, Matthew; Preece, John

    One of the key problems of applying solid oxide fuel cells (SOFCs) in transportation is that conventional fuels like kerosene and diesel do not operate directly in SOFCs without prereforming to hydrogen and carbon monoxide which can be handled by the nickel cermet anode. SOFCs can internally reform certain hydrocarbon molecules such as methanol and methane. However, other liquid fuels usable in petrol or diesel internal combustion engines (ICEs) have not easily been reformable directly on the anode. This paper describes a search for liquid fuels which can be mixed with petrol or diesel and also injected directly into an SOFC without destroying the nickel anode. When fuel molecules such as octane are injected onto the conventional nickel/yttria stabilised zirconia (Ni/YSZ) SOFC fuel electrode, the anode rapidly becomes blocked by carbon deposition and the cell power drops to near zero in minutes. This degeneration of the anode can be inhibited by injection of air or water into the anode or by some upstream reforming just before entry to the SOFC. Some smaller molecules such as methane, methanol and methanoic acid produce a slight tendency to carbon deposition but not sufficient to prevent long term operation. In this project we have investigated a large number of molecules and now found that some liquid ethers do not significantly damage the anode when directly injected. These molecules and formulations with other components have been evaluated in this study. The theory put forward in this paper is that carbon-carbon bonds in the fuel are the main reason for anode damage. By testing a number of fuels without such bonds, particularly liquid ethers such as methyl formate and dimethoxy methane, it has been shown that SOFCs can run without substantial carbon formation. The proposal is that conventional fuels can be doped with these molecules to allow hybrid operation of an ICE/SOFC device.

  14. Synthesis and Adsorption Property of Dihydroxyl Azacrown Ether-Grafted Chitosan

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel dihydroxyl azacrown ether chitosan was synthesized by reacting dihydroxyl azacrown ether with epoxy activated chitosan. The adsorption property of the azacrown ether chitosan for Pb2+, Cr3+, and Ag+, were determined. The experimental results showed that the dihydroxyl azacrown ether grafted chitosan has high adsorption capacity and high selectivity for some metal ions.

  15. Brain Tumors

    Science.gov (United States)

    A brain tumor is a growth of abnormal cells in the tissues of the brain. Brain tumors can be benign, with no cancer cells, or ... cancer cells that grow quickly. Some are primary brain tumors, which start in the brain. Others are metastatic, ...

  16. Brain Basics

    Medline Plus

    Full Text Available ... Basics will introduce you to some of this science, such as: How the brain develops How genes and the environment affect the brain The basic structure of the brain How different parts of the brain communicate and work with each other How changes in the brain ...

  17. Brain Tumors

    Science.gov (United States)

    A brain tumor is a growth of abnormal cells in the tissues of the brain. Brain tumors can be benign, with no cancer cells, ... cancer cells that grow quickly. Some are primary brain tumors, which start in the brain. Others are ...

  18. Brain Fingerprinting

    Directory of Open Access Journals (Sweden)

    ravi kumar

    2012-12-01

    Full Text Available Brain Fingerprinting is a scientific technique to determine whether or not specific information is stored in an individual's brain by measuring a electrical brain wave response to Word, phrases, or picture that are presented on computer screen. Brain Fingerprinting is a controversial forensic science technique that uses electroencephalograph y (EEG to determine whether specific information is stored in a subject's brain

  19. Brain Basics

    Medline Plus

    Full Text Available ... The Growing Brain Inside the Brain: Neurons & Neural Circuits Neurons are the basic working unit of the ... distant nerve cells (via axons) to form brain circuits. These circuits control specific body functions such as ...

  20. Brain Basics

    Medline Plus

    Full Text Available ... than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take pictures of the brain's structure, studies ...

  1. Brain Basics

    Medline Plus

    Full Text Available ... Brain Basics provides information on how the brain works, how mental illnesses are disorders of the brain, ... others live with symptoms of mental illness every day. They can be moderate, or serious and cause ...

  2. Brain Basics

    Medline Plus

    Full Text Available ... helps Sarah to better cope with her feelings. Brain Research Modern research tools and techniques are giving scientists ... the treatment for a person's specific conditions. Such brain research help increase the understanding of how the brain ...

  3. Brain Basics

    Medline Plus

    Full Text Available ... little dopamine or problems using dopamine in the thinking and feeling regions of the brain may play ... than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses ...

  4. Brain Basics

    Medline Plus

    Full Text Available ... as depression. The Growing Brain Inside the Brain: Neurons & Neural Circuits Neurons are the basic working unit of the brain ... specialized for the function of conducting messages. A neuron has three basic parts: Cell body which includes ...

  5. Brain Malformations

    Science.gov (United States)

    Most brain malformations begin long before a baby is born. Something damages the developing nervous system or causes it ... medicines, infections, or radiation during pregnancy interferes with brain development. Parts of the brain may be missing, ...

  6. Brain Basics

    Medline Plus

    Full Text Available ... brain's structure, studies show that brain growth in children with autism appears to peak early. And as ... grow there are differences in brain development in children who develop bipolar disorder than children who do ...

  7. Brain Basics

    Medline Plus

    Full Text Available ... Basics will introduce you to some of this science, such as: How the brain develops How genes and the environment affect the brain The basic structure of the brain How different parts of ...

  8. Brain Basics

    Medline Plus

    Full Text Available ... understanding of the brain than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take pictures ...

  9. Brain Basics

    Medline Plus

    Full Text Available ... science, such as: How the brain develops How genes and the environment affect the brain The basic ... that with brain development in people mental disorders. Genes and environmental cues both help to direct this ...

  10. Brain surgery

    Science.gov (United States)

    Craniotomy; Surgery - brain; Neurosurgery; Craniectomy; Stereotactic craniotomy; Stereotactic brain biopsy; Endoscopic craniotomy ... cut depends on where the problem in the brain is located. The surgeon creates a hole in ...

  11. Spatial trends of polybrominated diphenyl ether (PBDE) congeners

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Spatial trends of polybrominated diphenyl ether (PBDE) congeners were analyzed in young of the year bluefish collected along the U.S. Atlantic coastline from...

  12. The complicated ethers of glycerin and its functional derivatives

    International Nuclear Information System (INIS)

    The glycerides are complicated ethers of glycerin and fat acids. The glycerides call on incoming in their mixture remains of acids. The glycerides formed by palmitic acid have the name-palmitin, by stearine acids-stearins and etc

  13. Thermally reversible cross-linked poly(ether-urethanes

    Directory of Open Access Journals (Sweden)

    V. Gaina

    2013-07-01

    Full Text Available Cross-linked poly(ether-urethanes were prepared by Diels-Alder (DA reaction of the furan-containing poly(ether-urethane to bismaleimides and showed thermal reversibility evidenced by differential scanning calorimetry and attenuated total reflectance in conjunction with Fourier transform infrared spectroscopy (ATR-FTIR. The furan-containing poly(ether-urethanes were synthesized by the polyaddition reaction of 1,6-hexamethylene diisocyanate (HMDI or 4,4'- dibenzyl diisocyanate (DBDI to poly(tetramethylene ether glycol (PTMEG having Mn = 250, 650, 1000, 1500 and 2000 and 2-[N,N-bis(2-methyl-2-hydroxyethylamino]furfuryl as chain extender by the solution prepolymer method. The molar ratio of isocyanate: PTMEG:chain extender varied from 2:1:1 to 4:1:3, which produces a molar concentration of furyl group ranging between 3.65•10–4 and 1.25•10–3 mol/g.

  14. Catalytic rearrangement of the chloroallyl ethers of p-cresol

    International Nuclear Information System (INIS)

    The rearrangement of a series of p-cresol ethers (β- and γ-chloro-, βγ- and βγ,γ-trichloroallyl), catalyzed by boron trifluoride etherate, was studied. Increase in the number of chlorine atoms in the allyl unit of the ether hinders the rearrangement, and its mechanism changes in the investigated series of ethers from intramolecular [3,3]-sigmatropic (with inversion of the allyl unit) to intermolecular, which corresponds to electrophilic substitution in the aromatic ring (without inversion). The presence of the chlorine atom at the β position of the allyl unit promotes rearrangement by a concerted intramolecular mechanism, while a chlorine atom at the γ position promotes rearrangement by an intermolecular stage mechanism. Two chlorine atoms at the γ position give rise mainly to the intermolecular rearrangement path

  15. Evaluation of crystallization kinetics of poly (ether-ketone-ketone and poly (ether-ether-ketone by DSC

    Directory of Open Access Journals (Sweden)

    Gibran da Cunha Vasconcelos

    2010-08-01

    Full Text Available The poly (aryl ether ketones are used as matrices in advanced composites with high performance due to its high thermal stability, excellent environmental performance and superior mechanical properties. Most of the physical, mechanical and thermodynamic properties of semi-crystalline polymers depend on the degree of crystallinity and morphology of the crystalline regions. Thus, a study on the crystallization process promotes a good prediction of how the manufacturing parameters affect the developed structure, and the properties of the final product. The objective of this work was to evaluate the thermoplastics polymers PEKK e PEEK by DSC, aiming to obtain the relationship between kinetics, content, nucleation and geometry of the crystalline phases, according to the parameters of the Avrami and Kissinger models. The analysis of the Avrami exponents obtained for the studied polymers indicates that both showed the formation of crystalline phases with heterogeneous nucleation and growth geometry of the type sticks or discs, depending on the cooling conditions. It was also found that the PEEK has a higher crystallinity than PEKK.

  16. Brain mapping

    OpenAIRE

    Blaž Koritnik

    2004-01-01

    Cartography of the brain ("brain mapping") aims to represent the complexities of the working brain in an understandable and usable way. There are four crucial steps in brain mapping: (1) acquiring data about brain structure and function, (2) transformation of data into a common reference, (3) visualization and interpretation of results, and (4) databasing and archiving. Electrophysiological and functional imaging methods provide information about function of the human brain. A prere...

  17. Marine Sponge Dysidea herbacea revisited: Another Brominated Diphenyl Ether

    Directory of Open Access Journals (Sweden)

    Bruce F. Bowden

    2005-03-01

    Full Text Available Abstract: A pentabrominated phenolic diphenyl ether (1 that has not previously been reported from marine sources has been isolated from Dysidea herbacea collected at Pelorus Island, Great Barrier Reef, Australia. The structure was determined by comparison of NMR data with those of known structurally-related metabolites. NMR spectral assignments for (1 are discussed in context with those of three previously reported isomeric pentabrominated phenolic diphenyl ethers.

  18. Interpretation of the supraluminous neutrinos by a theory of ether

    OpenAIRE

    Delort, Thierry

    2011-01-01

    We exposed between the years 2000 to 2011 a very general theory of Ether, giving an interpretation of all the main experiments connected to Special and General Relativity and Cosmology. This theory of Ether was most of time even not considered, because it was contrary to Special Relativity. But a French team of physicists (led by Dario Autiero) recently realized an experiment, whose the result was contrary to Special Relativity, because it implied that a particle could go faster that the ligh...

  19. Interpretation of the Opera's experiment by a Theory of ether

    OpenAIRE

    Delort, Thierry

    2011-01-01

    5 pages We exposed between the years 2000 to 2011 a very general theory of Ether, giving an interpretation of all the main experiments connected to Special and General Relativity and Cosmology. This theory of Ether was most of time even not considered, because it was contrary to Special Relativity. But a French team of physicists (led by Dario Autiero) recently realized an experiment (Opera's experiment), whose the result was contrary to Special Relativity, because it implied that a partic...

  20. Highly efficient palladium-catalyzed hydrostannation of ethyl ethynyl ether

    OpenAIRE

    Andrews, Ian P.; Kwon, Ohyun

    2008-01-01

    The palladium-catalyzed hydrostannation of acetylenes is widely exploited in organic synthesis as a means of forming vinyl stannanes for use in palladium-catalyzed cross-coupling reactions. Application of this methodology to ethyl ethynyl ether results in an enol ether that is challenging to isolate from the crude reaction mixture because of incompatibility with typical silica gel chromatography. Reported here is a highly efficient procedure for the palladium-catalyzed hydrostannation of ethy...

  1. Effects of the ether phospholipid AMG-PC on mast cells are similar to that of the ether lipid AMG but different from that of the analogue hexadecylphosphocholine

    DEFF Research Database (Denmark)

    Grosman, Nina

    Farmakologi, ether phospholipid, hexacylphosphocholine, miltefosine, protein kinase C, AMG-PC(alkyl-methyl-glycero-phosphocholine), Histamine release, mast cell......Farmakologi, ether phospholipid, hexacylphosphocholine, miltefosine, protein kinase C, AMG-PC(alkyl-methyl-glycero-phosphocholine), Histamine release, mast cell...

  2. A local-ether model of propagation of electromagnetic wave

    International Nuclear Information System (INIS)

    It is pointed out that the classical propagation model can be in accord with the Sagnac effect due to earth's rotational and orbital motions in the high-precision GPS (global positioning system) and interplanetary radar, if the reference frame of the classical propagation medium is endowed with a switchability according to the location of the wave. Accordingly, it is postulated that, as in the obsolete theory, electromagnetic waves propagate via a medium like the ether. However, the ether is not universal. It is proposed that in the region under sufficient influence of the gravity due to the earth, the sun, or another celestial body, there forms a local ether, which in turn is stationary with respect to the gravitational potential of the respective body. For earthbound and interplanetary propagation, the medium is stationary in a geocentric and a heliocentric inertial frame, respectively. An electromagnetic wave propagates at a constant speed with respect to the associated local ether, independent of the motions of source and receiver. Based on this local-ether model of wave propagation, a wide variety of earthbound, interplanetary, and interstellar propagation phenomena are accounted for. Strong evidence of this new classical model is its consistent account of the Sagnac effect due to earth's motions among GPS, the intercontinental microwave link, and the interplanetary radar. Moreover, as examined within the present precision, this model is still in accord with the Michelson-Morley experiment. To test the local-ether propagation model, a one-way-link rotor experiment is proposed. (orig.)

  3. Adsorption of rare earths with crown ether adsorbents

    International Nuclear Information System (INIS)

    Crown ether - phosphotungstic acid (PW) and crown ether -phosphomolybdic acid (PMo) precipitates, and also the granular entrapped crown ether - PMo (or PW) in polyacrylamide, were prepared and applied as adsorbents for rare earth metal ions. Adsorbents containing 15-crown-5, such as 15-crown-5 - PMo, were better adsorbents than the other crown ether precipitates. The adsorption capacity of 15-crown-5 - PMo for Eu3+ was determined and corresponded to about 0.166 mmol of Eu3+ per gram of the absorbent. The effects of pH and metal ion concentration on adsorption were also investigated. Crown ether - PMo (or PW) precipitates underwent hydrolysis at pH >= 1, but the granular entrapped crown ether - PMo (or PW) - polyacrylamide adsorbents were not hydrolysed at pH >= 1. The adsorption of individual rare earth ions with 15-crown-5 - PMo - polyacrylamide showed that Tb3+, Nd3+, Eu3+ and Gd3+ were readily adsorbed, but adsorption was difficult for Ce4+, Sm3+ and Dy3+. (author)

  4. Review on Modification of Sulfonated Poly (-ether-ether-ketone Membranes Used as Proton Exchange Membranes

    Directory of Open Access Journals (Sweden)

    Xiaomin GAO

    2015-11-01

    Full Text Available The proton exchange membrane fuel cell (PEMFC is a type of modern power, but the traditional proton exchange membranes (PEM of PEMFC are limited by high methanol permeability and water uptake. Poly-ether-ether-ketone (PEEK is a widely used thermoplastic with good cost-effective property. Sulfonated poly (-ether-ether-ketone (SPEEK has high electric conductivity and low methanol permeability, as well as comprehensive property, which is expected to be used as PEMs. However, the proton exchange ability, methanol resistance, mechanical property and thermal stability of SPEEK are closely related to the degree of sulfonation (DS of SPEEK membranes. Additionally, the proton conductivity, methanol permeability, and stability of SPEEK membranes applied in various conditions need to be further improved. In this paper, the research into modification of SPEEK membranes made by SPEEK and other polymers, inorganic materials are introduced. The properties and modification situation of the SPEEK and the composite membranes, as well as the advantages and disadvantages of membranes prepared by different materials are summarized. From the results we know that, the methanol permeability of SPEEK/PES-C membranes is within the order of magnitude, 10-7cm2/s. The proton conductivity of the SPPESK/SPEEK blend membrane reaches 0.212 S cm-1 at 80 °C. The cross-linked SPEEK membranes have raised thermal and dimensional stability. The non-solvent caused aggregation of the SPEEK ionomers. The proton conductivity of SPEEK/50%BMIMPF6/4.6PA membrane maintains stable as 2.0 x 10-2S cm-1 after 600 h at 160 °C. Incorporation of aligned CNT into SPEEK increases the proton conductivity and reduces the methanol permeability of the composite membranes. The PANI improves the hydrothermal stability. More proton transfer sites lead to a more compact structure in the composite membranes. According to the results, the proton exchange capacity, water uptake, and conductivity of

  5. Conversion of dimethyl ether on zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Abramova, A.V.; Kulumbegov, R.V.; Khadzhiev, S.N. [Russian Academy of Sciences, Moscow (Russian Federation). A.V. Topchiev Inst. of Petrochemical Synthesis

    2006-07-01

    Catalytic conversion of dimethyl ether to hydrocarbons was investigated using zeolite catalyst ZSM-5 type. 2% MexOy - 60% HZVM(analogue of ZSM-5)/Al{sub 2}O{sub 3}, (Me = Zn, Ga, Fe, Co, V, Ni) catalyst samples have been obtained. The reaction was carried out in a fixed bed reaction set-up at 350-400 C, pressure 3 MPa, gas mix (% vol.): 24 DME, 76 N{sub 2}, WHSV=1300 l/l-{sub kat.}h. Most effective catalysts of DME conversion are pentasil based catalysts with promoter metals zinc, iron and cobalt by totality DME-conversion, gas and liquid hydrocarbon selectivity, ethylene and propylene content in gas. The best work temperatures are 350 and 375 C, thereupon increasing of temperature to 400 C leads to considerable growth of methane in hydrocarbon gas. Liquid hydrocarbons have high content of aromatics and iso-paraffins. Liquid hydrocarbon product is characterized by high octane number (RON) 90-98. (orig.)

  6. Radiation induced crosslinking of cellulose ethers

    International Nuclear Information System (INIS)

    The effects of high-energy radiation on four ethers of cellulose: carboxymethyl (CMC); hydroxypropyl (HPC), hydroxyethyl (HEC) and methylcellulose (MC) were investigated. Polymers are irradiated in solid state and in aqueous solutions at various concentrations. Degree of substitution (DS) of the derivatives, the concentration of their aqueous solutions and irradiation conditions had a significant impact on the obtained products. Irradiation of polymers in solid state and in diluted aqueous solutions resulted in their degradation. However, it was found that for concentrated solutions gel formation occurred. Paste-like form of the initial material, when water plasticizes the bulk of polymer as well as the high dose rate, what prevents oxygen penetration of the polymer during irradiation, have been found favourable for hydrogel formation. Up to 95% of gel fraction was obtained from solutions of CMC with concentration over 50% irradiated by γ-rays or electron beam. It was pointed out that the ability to the formation of the three-dimensional network is related to the DS of anhydroglucose units and a type of chemical group introduced to main chain of cellulose. Produced hydrogels swelled markedly in water. Despite of the crosslinked structure they underwent degradation by the action of cellulase enzyme or microorganisms from compost, and can be included into the group of biodegradable materials. (author)

  7. Explosion and detonation characteristics of dimethyl ether.

    Science.gov (United States)

    Mogi, Toshio; Horiguchi, Sadashige

    2009-05-15

    In this study, the explosion and detonation characteristics of dimethyl ether (DME) were experimentally investigated. A spherical pressure vessel with an internal volume of 180L was used as the explosion vessel. Therefore, tubes 10m in length with internal diameters of 25mm and 50mm were used as detonation tubes. In addition, we compared the characteristics of DME with those of propane since DME is considered as a substitute fuel for liquid petroleum gas (LPG). At room temperature and atmospheric pressure, the maximum explosive pressure increased tenfold. The explosion index (K(G) values), an indicator of the intensity of an explosion, was larger than that of propane, indicating that the explosion was intense. No experimental study has been conducted on the detonation behavior of DME so far, but this research confirmed a transition to detonation. The detonation characteristics were similar to the characteristics of the Chapman-Jouguet detonation, and the concentration range for detonation was from 5.5% to 9.0%. PMID:18774641

  8. Role of glutamate receptors in tetrabrominated diphenyl ether (BDE-47) neurotoxicity in mouse cerebellar granule neurons.

    Science.gov (United States)

    Costa, Lucio G; Tagliaferri, Sara; Roqué, Pamela J; Pellacani, Claudia

    2016-01-22

    The polybrominated diphenyl ether (PBDE) flame retardants are developmental neurotoxicants, as evidenced by numerous in vitro, animal and human studies. PBDEs can alter the homeostasis of thyroid hormone and directly interact with brain cells. Induction of oxidative stress, leading to DNA damage and apoptotic cell death is a prominent mechanism of PBDE neurotoxicity, though other mechanisms have also been suggested. In the present study we investigated the potential role played by glutamate receptors in the in vitro neurotoxicity of the tetrabromodiphenyl ether BDE-47, one of the most abundant PBDE congeners. Toxicity of BDE-47 in mouse cerebellar neurons was diminished by antagonists of glutamate ionotropic receptors, but not by antagonists of glutamate metabotropic receptors. Antagonists of NMDA and AMPA/Kainate receptors also inhibited BDE-47-induced oxidative stress and increases in intracellular calcium. The calcium chelator BAPTA-AM also inhibited BDE-47 cytotoxicity and oxidative stress. BDE-47 caused a rapid increase of extracellular glutamate levels, which was not antagonized by any of the compounds tested. The results suggest that BDE-47, by still unknown mechanisms, increases extracellular glutamate which in turn activates ionotropic glutamate receptors leading to increased calcium levels, oxidative stress, and ultimately cell death. PMID:26640238

  9. Mechanism and Effective Factors of Acyl Migration of Lysophospholipid%溶血磷脂酰基转移机理及有效影响因子研究

    Institute of Scientific and Technical Information of China (English)

    张康逸; 张丽霞; 屈凌波; 王兴国; 刘元法

    2014-01-01

    , detection of specific phospholipase A1, and the explanation of biosynthetic pathway (lysophospholipid inter-mediate) of the production mixed phospholipid.

  10. Brain Basics

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    Full Text Available ... in Real Life Brain Research Glossary Brain Basics (PDF, 10 pages) Introduction Watch the Brain Basics video ... early brain development, and may also assist in learning and memory. ... rise to disabilities or diseases. neural circuit —A network of neurons ...

  11. Brain Basics

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    Full Text Available ... than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take pictures of the brain's structure, studies show that brain growth in children with autism appears to peak early. And as ...

  12. Brain Basics

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    Full Text Available ... Research Modern research tools and techniques are giving scientists a more detailed understanding of the brain than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take pictures of the brain's structure, studies ...

  13. Brain Basics

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    Full Text Available ... Welcome. Brain Basics provides information on how the brain works, how mental illnesses are disorders of the brain, ... highly developed area at the front of the brain that, in humans, plays a role in executive functions such as ...

  14. A novel sulfonated poly(ether ether ketone) and cross-linked membranes for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongtao; Zhang, Gang; Wu, Jing; Zhao, Chengji; Zhang, Yang; Shao, Ke; Han, Miaomiao; Lin, Haidan; Zhu, Jing; Na, Hui [Alan G MacDiarmid Institute, College of Chemistry, Jilin University, Qianjin Street 2699, Changchun 130012, Jilin (China)

    2010-10-01

    A novel poly(ether ether ketone) (PEEK) containing pendant carboxyl groups has been synthesized by a nucleophilic polycondensation reaction. Sulfonated polymers (SPEEKs) with different ion exchange capacity are then obtained by post-sulfonation process. The structures of PEEK and SPEEKs are characterized by both FT-IR and {sup 1}H NMR. The properties of SPEEKs as candidates for proton exchange membranes are studied. The cross-linking reaction is performed at 140 C using poly(vinyl alcohol) (PVA) as the cross-linker. In comparison with the non-cross-linked membranes, some properties of the cross-linked membranes are significantly improved, such as water uptake, methanol resistance, mechanical and oxidative stabilities, while the proton conductivity decreases. The effect of PVA content on proton conductivity, water uptake, swelling ratio, and methanol permeability is also investigated. Among all the membranes, SPEEK-C-8 shows the highest selectivity of 50.5 x 10{sup 4} S s cm{sup -3}, which indicates that it is a suitable candidate for applications in direct methanol fuel cells. (author)

  15. Rheological, mechanical and tribological properties of carbon-nanofibre reinforced poly (ether ether ketone composites

    Directory of Open Access Journals (Sweden)

    Volker Altstaedt

    2003-12-01

    Full Text Available Poly(ether ether ketone nanocomposites containing vapour-grown carbon nanofibres (CNF were produced using standard polymer processing techniques. At high shear rates no significant increase in resin viscosity was observed. Nevertheless, the addition of the CNFs results in a higher melt strength at 360°C. Electron microscopy confirmed the homogeneous dispersion and alignment of nanofibres in the polymer matrix. Evaluation of the mechanical composite properties revealed a linear increase in tensile stiffness and strength with nanofibre loading fractions up to 15 wt% whilst matrix ductility was maintained up to 10 wt%. An interpretation of the composite performance by short-fibre theory resulted in rather low intrinsic stiffness properties of the vapour-grown CNF. Differential scanning calorimetry was used to investigate crystallization kinetics and degree of crystallinity. The CNFs were found not to act as nucleating sites. Furthermore, unidirectional sliding tests against two different counterpart materials (100Cr6 martensitic bearing steel, X5CrNi18-10 austenitic stainless steel were performed. The carbon nanofibres were found to reduce the wear rate of PEEK significantly.

  16. Electrical conductivity of sulfonated poly(ether ether ketone) based composite membranes containing sulfonated polyhedral oligosilsesquioxane

    Science.gov (United States)

    Celso, Fabricio; Mikhailenko, Serguei D.; Rodrigues, Marco A. S.; Mauler, Raquel S.; Kaliaguine, Serge

    2016-02-01

    Composite proton exchange membranes (PEMs) intended for fuel cell applications were prepared by embedding of various amounts of dispersed tri-sulfonic acid ethyl POSS (S-Et-POSS) and tri-sulfonic acid butyl POSS (S-Bu-POSS) in thin films of sulfonated poly ether-ether ketone. The electrical properties of the PEMs were studied by Impedance spectroscopy and it was found that their conductivity σ changes with the filler content following a curve with a maximum. The water uptake of these PEMs showed the same dependence. The investigation of initial isolated S-POSS substances revealed the properties of typical electrolytes, which however in both cases possessed low conductivities of 1. 17 × 10-5 S cm-1 (S-Et-POSS) and 3.52 × 10-5 S cm-1 (S-Bu-POSS). At the same time, the insoluble in water S-POSS was found forming highly conductive interface layer when wetted with liquid water and hence producing a strong positive impact on the conductivity of the composite PEM. Electrical properties of the composites were analysed within the frameworks of effective medium theory and bounding models, allowing to evaluate analytically the range of possible conductivity values. It was found that these approaches produced quite good approximation of the experimental data and constituted a fair basis for interpretation of the observed relationship.

  17. The Effects of Sulfonated Poly(ether ether ketone Ion Exchange Preparation Conditions on Membrane Properties

    Directory of Open Access Journals (Sweden)

    Rebecca S. L. Yee

    2013-08-01

    Full Text Available A low cost cation exchange membrane to be used in a specific bioelectrochemical system has been developed using poly(ether ether ketone (PEEK. This material is presented as an alternative to current commercial ion exchange membranes that have been primarily designed for fuel cell applications. To increase the hydrophilicity and ion transport of the PEEK material, charged groups are introduced through sulfonation. The effect of sulfonation and casting conditions on membrane performance has been systematically determined by producing a series of membranes synthesized over an array of reaction and casting conditions. Optimal reaction and casting conditions for producing SPEEK ion exchange membranes with appropriate performance characteristics have been established by this uniquely systematic experimental series. Membrane materials were characterized by ion exchange capacity, water uptake, swelling, potential difference and NMR analysis. Testing this extensive membranes series established that the most appropriate sulfonation conditions were 60 °C for 6 h. For mechanical stability and ease of handling, SPEEK membranes cast from solvent casting concentrations of 15%–25% with a resulting thickness of 30–50 µm were also found to be most suitable from the series of tested casting conditions. Drying conditions did not have any apparent impact on the measured parameters in this study. The conductivity of SPEEK membranes was found to be in the range of 10−3 S cm−1, which is suitable for use as a low cost membrane in the intended bioelectrochemical systems.

  18. Brain mapping

    Directory of Open Access Journals (Sweden)

    Blaž Koritnik

    2004-08-01

    Full Text Available Cartography of the brain ("brain mapping" aims to represent the complexities of the working brain in an understandable and usable way. There are four crucial steps in brain mapping: (1 acquiring data about brain structure and function, (2 transformation of data into a common reference, (3 visualization and interpretation of results, and (4 databasing and archiving. Electrophysiological and functional imaging methods provide information about function of the human brain. A prerequisite for multisubject, multidimensional and multimodal mapping is transformation of individual images to match a standard brain template. To produce brain maps, color, contours, and other visual cues are used to differentiate metabolic rates, electrical field potentials, receptor densities, and other attributes of structure or function. Databases are used to organize and archive data records. By relating the maps to cognitive functions and psychological models, brain mapping offers a prerequisite for the understanding of organizational principles of the human brain.

  19. Laboratory Method for Analysis of Small Concentrations of Methyl tert-Butyl Ether and Other Ether Gasoline Oxygenates in Water

    Science.gov (United States)

    Rose, Donna L.; Connor, Brooke F.; Abney, Sonja R.; Raese, Jon W.

    1998-01-01

    This Fact Sheet presents data for analysis of nanogram-per-liter concentrations of methyl tert-butyl ether (MTBE) and three other ether gasoline oxygenates, including methyl tert-pentyl ether (TAME), diisopropyl ether (DIPE), and ethyl tert-butyl ether (ETBE), by purge- and-trap capillary-column gas chromatography. Long-term method detection levels (LT-MDLs) for MTBE, TAME, DIPE, and ETBE ranged from 15 to 83 nanograms per liter (0.015 to 0.083 microgram per liter). Nanogram-per-liter-concentration detections are reported if all of the identification criteria are met, whereas previous methods censored detections at a pre-determined method reporting level. The reporting level for this method is defined as two times the LT-MDL, does not censor detections at less than this concentration, and is referred to as the nondetection value (NDV). Bias and variability data from multiple analyses, analysts, and instruments over a 60-day period show the oxygenate recoveries ranging from 100 to 109 percent, with 6 to 8 percent relative standard deviation. MTBE, TAME, DIPE, and ETBE were not detected in the analysis of 225 laboratory reagent blanks from January to December 1997. A preservation study in ground water and surface water indicates that all the oxygenates are stable at pH 2 for up to 216 days, with recoveries ranging from 94 to 115 percent on day 216, and relative standard deviations ranging from 5 to 9 percent for the duration of the study.

  20. Tandem Bond-Forming Reactions of 1-Alkynyl Ethers.

    Science.gov (United States)

    Minehan, Thomas G

    2016-06-21

    Electron-rich alkynes, such as ynamines, ynamides, and ynol ethers, are functional groups that possess significant potential in organic chemistry for the formation of carbon-carbon bonds. While the synthetic utility of ynamides has recently been expanded considerably, 1-alkynyl ethers, which possess many of the reactivity features of ynamides, have traditionally been far less investigated because of concerns about their stability. Like ynamides, ynol ethers are relatively unhindered to approach by functional groups present in the same or different molecules because of their linear geometry, and they can potentially form up to four new bonds in a single transformation. Ynol ethers also possess unique reactivity features that make them complementary to ynamides. Research over the past decade has shown that ynol ethers formed in situ from stable precursors engage in a variety of useful carbon-carbon bond-forming processes. Upon formation at -78 °C, allyl alkynyl ethers undergo a rapid [3,3]-sigmatropic rearrangement to form allyl ketene intermediates, which may be trapped with alcohol or amine nucleophiles to form γ,δ-unsaturated carboxylic acid derivatives. The process is stereospecific, takes place in minutes at cryogenic temperatures, and affords products containing (quaternary) stereogenic carbon atoms. Trapping of the intermediate allyl ketene with carbonyl compounds, epoxides, or oxetanes instead leads to complex α-functionalized β-, γ-, or δ-lactones, respectively. [3,3]-Sigmatropic rearrangement of benzyl alkynyl ethers also takes place at temperatures ranging from -78 to 60 °C to afford substituted 2-indanones via intramolecular carbocyclization of the ketene intermediate. tert-Butyl alkynyl ethers containing pendant di- and trisubstituted alkenes and enol ethers are stable to chromatographic isolation and undergo a retro-ene/[2 + 2] cycloaddition reaction upon mild thermolysis (90 °C) to afford cis-fused cyclobutanones and donor

  1. Influence of Cellulose Ethers on Hydration Products of Portland Cement

    Institute of Scientific and Technical Information of China (English)

    MA Baoguo; OU Zhihua; JIAN Shouwei; XU Rulin

    2011-01-01

    Cellulose ethers are widely used to mortar formulations, and it is significant to understand the interaction between cellulose ethers and cement pastes. FT-IR spectra, thermal analysis and SEM are used to investigate hydration products in the cement pastes modified by HEMC and HPMC in this article. The results show that the hydration products in modified cement pastes were finally identical with those in the unmodified cement paste, but the major hydration products, such as CH (calcium hydroxide), ettringite and C-S-H, appeared later in the modified cement pastes than in the unmodified cement paste. The cellulose ethers decrease the outer products and increase inner products of C-S-H gels. Compared to unmodified cement pastes, no new products are found in the modified cement pastes in the present experiment. The HEMC and HPMC investigation shows almost the same influence on the hydration products of Portland cement.

  2. Brain Basics

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    Full Text Available ... the anatomy, physiology, and chemistry of the nervous system. When the brain cannot effectively coordinate the billions ... basic working unit of the brain and nervous system. These cells are highly specialized for the function ...

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  4. Brain Basics

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    Full Text Available ... Neurons & Neural Circuits Neurons are the basic working unit of the brain and nervous system. These cells ... A nerve cell that is the basic, working unit of the brain and nervous system, which processes ...

  5. Brain Basics

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    Full Text Available ... Trials — Participants Statistics Help for Mental Illnesses Outreach Research Priorities Funding Labs at NIMH News About Us Home > Health & Education > Educational Resources Brain Basics Introduction The Growing Brain The ...

  6. Brain Basics

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    Full Text Available ... brain may play a role in disorders like schizophrenia or attention deficit hyperactivity disorder (ADHD) . Glutamate —the ... mental disorders, including autism , obsessive compulsive disorder (OCD) , schizophrenia , and depression . Brain Regions Just as many neurons ...

  7. Brain Basics

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    Full Text Available ... medical professionals who can diagnose mental disorders are psychologists or clinical social workers. The psychiatrist asked Sarah ... important research tool in understanding how the brain functions. Another type of brain scan called magnetoencephalography, or ...

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    Full Text Available ... normal brain development and function can go awry, leading to mental illnesses. Brain Basics will introduce you ... of DNA. Sometimes this copying process is imperfect, leading to a gene mutation that causes the gene ...

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    Full Text Available ... and epigenetic changes can be passed on to future generations. Further understanding of genes and epigenetics may ... than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses ...

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    Full Text Available ... body, the results can affect many aspects of life. Scientists are continually learning more about how the brain grows and works in healthy people, and how normal brain development and function ...

  12. Brain Basics

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    Full Text Available ... problems using dopamine in the thinking and feeling regions of the brain may play a role in ... obsessive compulsive disorder (OCD) , schizophrenia , and depression . Brain Regions Just as many neurons working together form a ...

  13. Brain Basics

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    Full Text Available ... medications could reduce the amount of trial and error and frustration that many people with depression experience ... early brain development, and may also assist in learning and memory. hippocampus —A portion of the brain ...

  14. Brain Basics

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    Full Text Available ... Brain Basics will introduce you to some of this science, such as: How the brain develops How ... cell, and responds to signals from the environment; this all helps the cell maintain its balance with ...

  15. Brain Basics

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    Full Text Available ... Life Brain Basics in Real Life—How Depression affects the Brain Meet Sarah Sarah is a middle- ... However, recent research points to a possible new class of antidepressants that can relieve symptoms of the ...

  16. Brain Basics

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    Full Text Available ... than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses ... depression experience when starting treatment. Gene Studies Advanced technologies are also making it faster, easier, and more ...

  17. Brain Basics

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    Full Text Available ... have been linked to many mental disorders, including autism , obsessive compulsive disorder (OCD) , schizophrenia , and depression . Brain ... studies show that brain growth in children with autism appears to peak early. And as they grow ...

  18. Brain Basics

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    Full Text Available ... body, the results can affect many aspects of life. Scientists are continually learning more about how the brain grows and works in healthy people, and how normal brain development ...

  19. Brain Diseases

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    The brain is the control center of the body. It controls thoughts, memory, speech, and movement. It regulates the function of many organs. When the brain is healthy, it works quickly and automatically. However, ...

  20. Brain Basics

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    Full Text Available ... working unit of the brain and nervous system. These cells are highly specialized for the function of ... nerve cells (via axons) to form brain circuits. These circuits control specific body functions such as sleep ...

  1. Brain Basics

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    Full Text Available ... speech. The brain continues maturing well into a person's early 20s. Knowing how the brain is wired ... in Parkinson's disease, a disorder that affects a person's ability to move as they want to, resulting ...

  3. Brain Basics

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    Full Text Available ... of brain scan called magnetoencephalography, or MEG, can capture split-second changes in the brain. Using MEG, ... The study of how environmental factors like diet, stress and post-natal care can change gene expression ( ...

  4. Brain Basics

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    Full Text Available ... neurons, the most highly specialized cells of all, conduct messages. Every cell in our bodies contains a ... brain's structure, studies show that brain growth in children with autism appears to peak early. And as ...

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    Full Text Available ... Real Life Brain Basics in Real Life—How Depression affects the Brain Meet Sarah Sarah is a ... volunteers PubMed Central: An archive of life sciences journals NIH Research Fact Sheets NIH Office of Science ...

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  9. Brain Basics

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    Full Text Available ... affect many aspects of life. Scientists are continually learning more about how the brain grows and works ... early brain development. It may also assist in learning and memory. Problems in making or using glutamate ...

  10. Brain Basics

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    Full Text Available ... all. She was happily married and successful in business. Then, after a serious setback at work, she ... than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses ...

  11. Brain Basics

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    Full Text Available ... and the environment affect the brain The basic structure of the brain How different parts of the ... for the cell to work properly including small structures called cell organelles. Dendrites branch off from the ...

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    Full Text Available ... may help improve treatments for anxiety disorders like phobias or post-traumatic stress disorder (PTSD) . Prefrontal cortex ( ... brain's structure, studies show that brain growth in children with autism appears to peak early. And as ...

  13. Brain Basics

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    Full Text Available ... Real Life Brain Basics in Real Life—How Depression affects the Brain Meet Sarah Sarah is a ... blues" from time to time. In contrast, major depression is a serious disorder that lasts for weeks. ...

  14. Novel Unsaturated Sucrose Ethers and Their Application as Monomers

    Directory of Open Access Journals (Sweden)

    Maria T. Barros

    2007-03-01

    Full Text Available Novel unsaturated ethers were synthesised in good yields starting from sucrose,using a two-step mild and efficient procedure based on the Gassman method, whichconsists in forming a vinyl group by the elimination of ethanol from mixed acetals withtrimethylsilyl trifluoromethanesulfonate in the presence of alkyl amines. Mixed acetals arereadily obtained from the corresponding alcohols and ethyl vinyl ether, using an acidiccatalyst. Conventional etherification involving a primary halide was also examined. Themonomers thus obtained were successfully polymerised by a free radical mechanism,yielding unbranched linear and soluble polymers with pending sucrose moieties, and someof their physical properties were determined.

  15. Effect of Parameters on Oxychlorination of Tert-Butyl Ethers

    OpenAIRE

    Gaca, Jerzy; Gackowska, Alicja; Belt, Natalia

    2008-01-01

    The effect of concentration, molar ratios of reagents, pH, and temperature on formation of chloro-organic products in reaction of tert-butyl ethers with chloride ions and hydrogen peroxide has been determined. A significant effect of Cl− ions and H2O2 molar ratios on the rate of chloro-organic product formation has been observed. Studies on oxychlorination of tert-butylethyl ether (ETBE) at pH 7, 3.5, and 2.5 have been carried out. It was found that introduction of hydronium ions into the rea...

  16. Concise synthesis of ether analogues of lysobisphosphatidic acid.

    Science.gov (United States)

    Jiang, Guowei; Xu, Yong; Falguières, Thomas; Gruenberg, Jean; Prestwich, Glenn D

    2005-09-01

    We describe a versatile, efficient method for the preparation of ether analogues of (S,S)-lysobisphosphatidic acid (LBPA) and its enantiomer from (S)-solketal. Phosphorylation of a protected sn-2-O-octadecenyl glyceryl ether with 2-cyanoethyl bis-N,N-diisopropylamino phosphine and subsequent deprotection generated the bisether LBPA analogues. By simply changing the sequence of deprotection steps, we obtained the (R,R)- and (S,S)-enantiomers of 2,2'-bisether LBPA. An ELISA assay with anti-LBPA monoclonal antibodies showed that the bisether LBPAs were recognized with the same affinity as the natural 2,2'-bisoleolyl LBPA. [reaction: see text] PMID:16119911

  17. Mutual solubility in the system uranyl trichloroacetate--water--diethyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Vdovenko, V.M.; Baluev, A.V.; Suglobova, I.G.

    1975-01-01

    A study was made of mutual solubility in the system uranyl trichloroacetate--water--diethyl ether at 25/sup 0/C. It was found that the solubility of the salt in ether and the composition of the lower phase depend on the water content of the ternary system. On the basis of ir spectra of ether solutions of uranyl trichloroacetate in the presence of semiheavy water (HDO) the structure of the hydration envelope of the complex in diethyl ether was established.

  18. Effect of Backbone Structure on Membrane Properties for Poly(arylene ether) Random and Multiblock Copolymers

    OpenAIRE

    Rowlett, Jarrett Robert

    2014-01-01

    Poly(arylene ether)s are a well-established class of thermoplastics that are known for their mechanical toughness, thermal stability, and fabrication into membranes. These materials can undergo a myriad of modifications including backbone structure variability, sulfonation, and crosslinking. In this dissertation, structure-property relationships are considered for poly(arylene ether)s with regard to membrane applications for proton exchange and gas separation membranes. All of the proton...

  19. Brain Basics

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    Full Text Available ... pituitary-adrenal (HPA) axis. Brain Basics in Real Life Brain Basics in Real Life—How Depression affects the Brain Meet Sarah Sarah ... having trouble coping with the stresses in her life. She began to think of suicide because she ...

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    Full Text Available ... Life Brain Basics in Real Life—How Depression affects the Brain Meet Sarah Sarah is a middle-aged woman ... new memories. hypothalmic-pituitary-adrenal (HPA) axis —A brain-body ... stress. impulse —An electrical communication signal sent between neurons ...

  1. Brain Aneurysm

    Science.gov (United States)

    A brain aneurysm is an abnormal bulge or "ballooning" in the wall of an artery in the brain. They are sometimes called berry aneurysms because they ... often the size of a small berry. Most brain aneurysms produce no symptoms until they become large, ...

  2. Brain Basics

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    Full Text Available ... other cells guide neurons in forming various brain structures. Neighboring neurons make connections with each other and with distant nerve cells (via axons) to form brain circuits. These circuits control specific body functions such as sleep and speech. The brain continues ...

  3. Left Brain. Right Brain. Whole Brain

    Science.gov (United States)

    Farmer, Lesley S. J.

    2004-01-01

    As the United States student population is becoming more diverse, library media specialists need to find ways to address these distinctive needs. However, some of these differences transcend culture, touching on variations in the brain itself. Most people have a dominant side of the brain, which can affect their personality and learning style.…

  4. 40 CFR 721.1580 - Disubstituted benzene ether, polymer with substituted phenol (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Disubstituted benzene ether, polymer... Significant New Uses for Specific Chemical Substances § 721.1580 Disubstituted benzene ether, polymer with... chemical substance generically identified as disubstituted benzene ether, polymer with substituted...

  5. Carboxymethyl ethers of cellulose obtained from secondary products of fine-stapled cotton

    International Nuclear Information System (INIS)

    This article is devoted to synthesis and properties of carboxymethyl ethers of cellulose obtained from secondary products of fine-stapled cotton. The investigation of extraction conditions of cellulose on the quality of carboxymethyl ethers of cellulose is conducted. The qualitative characteristics of cotton cellulose are considered. The synthesis of carboxymethyl ethers of cellulose from obtained cellulose is described.

  6. Synthesis of Hydroxytyrosyl Alkyl Ethers from Olive Oil Waste Waters

    Directory of Open Access Journals (Sweden)

    Juan Fernández-Bolaños

    2009-05-01

    Full Text Available The preparation of a new type of derivatives of the naturally occurring antioxidant hydroxytyrosol is reported. Hydroxytyrosyl alkyl ethers were obtained in high yield by a three-step procedure starting from hydroxytyrosol isolated from olive oil waste waters. Preliminary results obtained by the Rancimat method have shown that these derivatives retain the high protective capacity of free hydroxytyrosol.

  7. Aqueous alkali metal hydroxide insoluble cellulose ether membrane

    Science.gov (United States)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1969-01-01

    A membrane that is insoluble in an aqueous alkali metal hydroxide medium is described. The membrane is a resin which is a water-soluble C2-C4 hydroxyalkyl cellulose ether polymer and an insolubilizing agent for controlled water sorption, a dialytic and electrodialytic membrane. It is particularly useful as a separator between electrodes or plates in an alkaline storage battery.

  8. Selected Methods of Dehalogenation of Polybrominated Diphenyl Ethers

    Czech Academy of Sciences Publication Activity Database

    Vajglová, Zuzana; Vychodilová, Hana; Křišťál, Jiří; Kaštánek, František; Jiřičný, Vladimír

    Frankfurt: DECHEMA, 2011, P05.04. ISBN N. [European Congress of Chemical Engineering /8./. Berlin (DE), 25.09.2011-29.09.2011] Institutional research plan: CEZ:AV0Z40720504 Keywords : polybrominated diphenyl ethers * concentrations * waste waters Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  9. Synthesis of Hydroxytyrosyl Alkyl Ethers from Olive Oil Waste Waters

    OpenAIRE

    2009-01-01

    The preparation of a new type of derivatives of the naturally occurring antioxidant hydroxytyrosol is reported. Hydroxytyrosyl alkyl ethers were obtained in high yield by a three-step procedure starting from hydroxytyrosol isolated from olive oil waste waters. Preliminary results obtained by the Rancimat method have shown that these derivatives retain the high protective capacity of free hydroxytyrosol.

  10. Allyl ethers of the 1-alkoxy-2,3-propandiol

    International Nuclear Information System (INIS)

    With the purpose of study of 1-alkoxy-2,3-propandiol allying reaction wasobtained their mono- and diallyl ethers by authors of this article. Theinitial 1-alkoxy-2,3-propandiol was synthesised from mono chlor-hydrin ofglycerin and alcoholates of alcohols of saturated line (C1-C5) and theirisomers

  11. Photodegradation of poly(ether sulphone). Part 2

    DEFF Research Database (Denmark)

    Norrman, K.; Krebs, Frederik C

    2004-01-01

    The photodegradation of poly(ether sulphone) (PES) was investigated systematically by time-of-flight SIMS (ToF-SIMS) and x-ray photoelectron spectroscopy (XPS). The effect of varying the irradiation dose, wavelength and the atmosphere was studied along with mechanistic photooxidation studies using...

  12. Li-air batteries having ether-based electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Amine, Khalil; Curtiss, Larry A; Lu, Jun; Lau, Kah Chun; Zhang, Zhengcheng; Sun, Yang-Kook

    2015-03-03

    A lithium-air battery includes a cathode including a porous active carbon material, a separator, an anode including lithium, and an electrolyte including a lithium salt and polyalkylene glycol ether, where the porous active carbon material is free of a metal-based catalyst.

  13. Enzymatic network for production of ether amines from alcohols

    DEFF Research Database (Denmark)

    Palacio, Cyntia M.; Crismaru, Ciprian G.; Bartsch, Sebastian;

    2016-01-01

    We constructed an enzymatic network composed of three different enzymes for the synthesis of valuable ether amines. The enzymatic reactions are interconnected to catalyze the oxidation and subsequent transamination of the substrate and to provide cofactor recycling. This allows production of the ...

  14. The ether lipid-deficient mouse: tracking down plasmalogen functions.

    Science.gov (United States)

    Gorgas, Karin; Teigler, Andre; Komljenovic, Dorde; Just, Wilhelm W

    2006-12-01

    Chemical and physico-chemical properties as well as physiological functions of major mammalian ether-linked glycerolipids, including plasmalogens were reviewed. Their chemical structures were described and their effect on membrane fluidity and membrane fusion discussed. The recent generation of mouse models with ether lipid deficiency offered the possibility to study ether lipid and particularly plasmalogen functions in vivo. Ether lipid-deficient mice revealed severe phenotypic alterations, including arrest of spermatogenesis, development of cataract and defects in central nervous system myelination. In several cell culture systems lack of plasmalogens impaired intracellular cholesterol distribution affecting plasma membrane functions and structural changes of ER and Golgi cisternae. Based on these phenotypic anomalies that were accurately described conclusions were drawn on putative functions of plasmalogens. These functions were related to cell-cell or cell-extracellular matrix interactions, formation of lipid raft microdomains and intracellular cholesterol homeostasis. There are several human disorders, such as Zellweger syndrome, rhizomelic chondrodysplasia punctata, Alzheimer's disease, Down syndrome, and Niemann-Pick type C disease that are distinguished by altered tissue plasmalogen concentrations. The role plasmalogens might play in the pathology of these disorders is discussed. PMID:17027098

  15. Synthesis of new indolyl crown ethers catalyzed with ferric hydrogensulfate

    Institute of Scientific and Technical Information of China (English)

    Hossein Eshghi; Mohammad Rahimizadeh; Zahra Bakhtiarpoor; Mehdi Pordel

    2012-01-01

    Efficient reaction of bis-indolyl podand with different aldehydes using Fe(HSO4)3 as catalyst to afford the corresponding new indolyl crown ethers is described.The structures of three distinct isomers have been optimized using HyperChem geometry optimizations.Also percentage of each isomer was obtained with 1H NMR spectroscopy.

  16. Numerical investigation on the effect of injection pressure on the internal flow characteristics for diethyl ether, dimethyl ether and diesel fuel injectors using CFD

    OpenAIRE

    Vijayakumar Thulasi; Thundil Karrupa Raj Rajagopal; Nanthagopal Kasianantham

    2011-01-01

    The spray characteristics of the diesel fuel are greatly affected by the cavitation formed inside the injector due to the high pressure differential across the nozzle. Many researchers across the globe are exploring the potential of using diethyl ether and dimethyl ether as an alternate for diesel fuel to meet the strict emission norms. Due to the variation in the fuel properties the internal flow characteristics in injectors for ether fuels are expected to be different from that of the...

  17. A mild and efficient procedure for the synthesis of ethers from various alkyl halides

    Directory of Open Access Journals (Sweden)

    Mosstafa Kazemi

    2013-10-01

    Full Text Available A simple, mild and practical procedure has been developed for the synthesis of symmetrical and unsymmetrical ethers by using DMSO, TBAI in the presence of K2CO3. We extended the utility of Potassium carbonate as an efficient base for the preparation of ethers. A wide range of alkyl aryl and dialkyl ethers are synthezied from treatment of aliphatic alcohols and phenols with various alkyl halides in the prescence of efficient base Potassium carbonate. Secondary alkyl halides were easily converted to corresponding ethers in releatively good yields . This is a mild, simple and practical procedure for the preparation of ethers in high yields and suitable times under mild condition.

  18. Comparative photophysical behaviour of naphthalene-linked crown ethers and aza crown ethers of varying cavity dimensions

    Indian Academy of Sciences (India)

    Subhodip Samanta; Pinki Saha Sardar; Shyam Sundar Maity; Anirban Pal; Maitrayee Basu Roy; Sanjib Ghosh

    2007-03-01

    A comparative time-resolved emission studies of several naphtho-crown ethers I-V, where metal ions can be complexed in a predetermined orientation with respect to the naphthalene (Naph) - plane and naphthalene-linked aza crown ethers (L1 and L2) have been presented. In both the systems, crown ethers and aza crown ethers, naphthalene fluorescence gets quenched. In the systems I to V, the quenching is mainly due to efficient spin-orbit coupling (SOC) leading to greater population of the lowest triplet state of naphthalene. This SOC depends on the orientation of the crown ring with respect to the Naph--plane. However, in the systems L1 and L2, the quenching is due to photoinduced electron transfer (PET) from nitrogen lone pair of the aza crown ring to naphthalene moiety and consequent exciplex formation. The results have been interpreted using the time-resolved emission studies of all the compounds in various solvents, their alkali metal ion complexes, and protonated ligands.

  19. Enhanced response of microbial fuel cell using sulfonated poly ether ether ketone membrane as a biochemical oxygen demand sensor

    Energy Technology Data Exchange (ETDEWEB)

    Ayyaru, Sivasankaran; Dharmalingam, Sangeetha, E-mail: sangeetha@annauniv.edu

    2014-03-01

    Graphical abstract: - Highlights: • Sulfonated poly ether ether ketone (SPEEK) membrane in SCMFC used to determine the BOD. • The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm. • This sensing range was 62.5% higher than that of Nafion{sup ®}. • SPEEK exhibited one order lesser oxygen permeability than Nafion{sup ®}. • Nafion{sup ®} shows high anodic internal resistance (67 Ω) than the SPEEK (39 Ω). - Abstract: The present study is focused on the development of single chamber microbial fuel cell (SCMFC) using sulfonated poly ether ether ketone (SPEEK) membrane to determine the biochemical oxygen demand (BOD) matter present in artificial wastewater (AW). The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm when using artificial wastewater. This sensing range was 62.5% higher than that of Nafion{sup ®}. The most serious problem in using MFC as a BOD sensor is the oxygen diffusion into the anode compartment, which consumes electrons in the anode compartment, thereby reducing the coulomb yield and reducing the electrical signal from the MFC. SPEEK exhibited one order lesser oxygen permeability than Nafion{sup ®}, resulting in low internal resistance and substrate loss, thus improving the sensing range of BOD. The system was further improved by making a double membrane electrode assembly (MEA) with an increased electrode surface area which provide high surface area for electrically active bacteria.

  20. Enhanced response of microbial fuel cell using sulfonated poly ether ether ketone membrane as a biochemical oxygen demand sensor

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Sulfonated poly ether ether ketone (SPEEK) membrane in SCMFC used to determine the BOD. • The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm. • This sensing range was 62.5% higher than that of Nafion®. • SPEEK exhibited one order lesser oxygen permeability than Nafion®. • Nafion® shows high anodic internal resistance (67 Ω) than the SPEEK (39 Ω). - Abstract: The present study is focused on the development of single chamber microbial fuel cell (SCMFC) using sulfonated poly ether ether ketone (SPEEK) membrane to determine the biochemical oxygen demand (BOD) matter present in artificial wastewater (AW). The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm when using artificial wastewater. This sensing range was 62.5% higher than that of Nafion®. The most serious problem in using MFC as a BOD sensor is the oxygen diffusion into the anode compartment, which consumes electrons in the anode compartment, thereby reducing the coulomb yield and reducing the electrical signal from the MFC. SPEEK exhibited one order lesser oxygen permeability than Nafion®, resulting in low internal resistance and substrate loss, thus improving the sensing range of BOD. The system was further improved by making a double membrane electrode assembly (MEA) with an increased electrode surface area which provide high surface area for electrically active bacteria

  1. Brain glycogen

    DEFF Research Database (Denmark)

    Obel, Linea Lykke Frimodt; Müller, Margit S; Walls, Anne B;

    2012-01-01

    Glycogen is a complex glucose polymer found in a variety of tissues, including brain, where it is localized primarily in astrocytes. The small quantity found in brain compared to e.g., liver has led to the understanding that brain glycogen is merely used during hypoglycemia or ischemia....... In this review evidence is brought forward highlighting what has been an emerging understanding in brain energy metabolism: that glycogen is more than just a convenient way to store energy for use in emergencies-it is a highly dynamic molecule with versatile implications in brain function, i.e., synaptic...... activity and memory formation. In line with the great spatiotemporal complexity of the brain and thereof derived focus on the basis for ensuring the availability of the right amount of energy at the right time and place, we here encourage a closer look into the molecular and subcellular mechanisms...

  2. Biodegradability of fuel-ethers in environment; Biodegradabilite des ethers-carburants dans l'environnement

    Energy Technology Data Exchange (ETDEWEB)

    Fayolle-Guichard, F.

    2005-04-01

    Fuel ethers (methyl tert-butyl ether or MTBE, ethyl tert-butyl ether or ETBE and tert-amyl methyl ether or TAME have been used as gasoline additives since about twenty years in order to meet the requirements for the octane index and to limit the polluting emission in exhaust pipe gas (unburnt hydrocarbons and carbon monoxide). The high water solubility and the poor biodegradability of these compounds make them pollutants frequently encountered in aquifers. The present manuscript summarizes the knowledge concerning the biodegradability of fuel ethers obtained both at IFP and during collaborations with the Pasteur Institute (Paris), the Biotechnology Research Institute (Montreal, Canada) and the Center for Environmental Biotechnology (University of Tennessee, USA). Rhodococcus ruber IFP 2001 and Mycobacterium austroafricanum IFP 2012, two microorganisms isolated at IFP for their ability to grow, respectively, on ETBE and MTBE, were studied in order to determine the intermediates produced during MTBE and ETBE biodegradation and the enzymes required for each biodegradation step, thus allowing us to propose MTBE and ETBE catabolic pathways. A proteomic approach, from the protein induced during the degradation of ETBE or MTBE to the genes encoding these different enzymes, was carried out. The isolation of such genes is required:1) to use them for help in determining the bio-remediation capacities in polluted aquifers (DNA micro-arrays), 2) to monitor the microorganisms isolated for their degradative capacities during bio-remediation processes (fluorescent in situ hybridization or FISH) and 3) to create new tools for the detection and the quantification of ETBE or MTBE in contaminated aquifers (bio-sensor). The manuscript also describes the different ways for the adaptation of microorganisms to the presence of a xenobiotic compound. (author)

  3. Clinical study on lysophospholipids acid, D_dimers detection in the prediction of progress and application effect of cerebral apoplexy%溶血磷脂酸、D-二聚体检测预测进展性脑卒中的临床应用研究

    Institute of Scientific and Technical Information of China (English)

    胡红晓

    2014-01-01

    Objective:To study the lysophospholipids acid , D_dimers detection in the prediction of progress and application effect of cerebral apoplexy .Methods:Our hospital in April 2012 to April 2013 were 35 patients with progressive stroke ( research group ) , physical examination, 35 cases (control group) as the research object, research on two groups of objects of D -dimer, lysophosphatide acid level testing and comparison .Results:The group D -dimer level of patients >75 mu g/L, positive;Control the research object of D -dimer level <75 mu g/L, negative;Group patients were lysophospholipids , D -dimer acid average levels were significantly higher than that of control group, P <0.05).Conclusion:D -dimer, lysophosphatide acid was an important molecular markers of early thrombosis in vivo, by detecting D -dimer, lysophosphatide acid levels , could provide effective basis for clinical prediction progress sex stroke .%目的:探讨溶血磷脂酸、D-二聚体检测在预测进展性脑卒中的应用效果。方法:选取我院在2012年4月~2013年4月收治的进展性脑卒中患者35例(研究组)、健康体检者35例(对照组)作为研究对象,对2组研究对象的D-二聚体、溶血磷脂酸水平进行检测、比较。结果:研究组患者的D-二聚体水平均>75μg/L,呈阳性;对照组研究对象的D-二聚体水平均<75μg/L,呈阴性;研究组患者的溶血磷脂酸、D-二聚体平均水平均显著高于对照组,P<0.05。结论:D-二聚体、溶血磷脂酸是体内早期血栓形成的重要分子标志物,通过检测D-二聚体、溶血磷脂酸水平,可为临床预测进展性脑卒中提供有效依据。

  4. Pra Rancangan Pabrik Pembuatan Shampoo Dengan Bahan Baku Sodium Layryl Ether Sulfonat Kapasitas Produksi 8.000 Ton / Tahun

    OpenAIRE

    Herri Putra

    2009-01-01

    Pabrik Shampoo ini direncanakan berproduksi dengan kapasitas 8.000 ton/tahun dengan 340 hari kerja dalam 1 (satu) tahun. Proses yang digunakan melalui 2 tahap yaitu proses pembuatan Lauryl Ether Sulfonat dan proses pembuatan shampoo. Pembuatan Lauryl Ether Sulfonat dilakukan melalui proses pencampuran Lauryl ether dengan oleum 20% di sulfonator (R-101) dengan temperatur proses 46oC sehingga terbentuk senyawa lauryl ether sulfonat. Kemudian lauryl ether sulfonat ini dinetralisasi dengan mengg...

  5. Pra Rancangan Pabrik Pembuatan Shampoo Dengan Bahan Baku Sodium Layryl Ether Sulfonat Kapasitas Produksi 10.000 Ton / Tahun

    OpenAIRE

    Muhammad Dimas Arhadiansyah

    2009-01-01

    Pabrik Shampoo ini direncanakan berproduksi dengan kapasitas 8.000 ton/tahun dengan 340 hari kerja dalam 1 (satu) tahun. Proses yang digunakan melalui 2 tahap yaitu proses pembuatan Lauryl Ether Sulfonat dan proses pembuatan shampoo. Pembuatan Lauryl Ether Sulfonat dilakukan melalui proses pencampuran Lauryl ether dengan oleum 20% di sulfonator (R-101) dengan temperatur proses 46oC sehingga terbentuk senyawa lauryl ether sulfonat. Kemudian lauryl ether sulfonat ini dinetralisasi dengan mengg...

  6. Brain Basics

    Medline Plus

    Full Text Available ... as they grow there are differences in brain development in children who develop bipolar disorder than children who do not. Studies comparing such children to those with normal brain development may help scientists to pinpoint when and where ...

  7. Brain Basics

    Medline Plus

    Full Text Available ... PTSD) . Prefrontal cortex (PFC) —Seat of the brain's executive functions, such as judgment, decision making, and problem solving. ... brain that, in humans, plays a role in executive functions such as judgment, decision making and problem solving, ...

  8. Brain Basics

    Medline Plus

    Full Text Available ... Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take ... to slow or stop them from progressing. Functional magnetic resonance imaging (fMRI) is another important research tool in ...

  9. Brain Basics

    Medline Plus

    Full Text Available ... in brain development in children who develop bipolar disorder than children who do not. Studies comparing such children to those with normal brain development may help scientists to pinpoint when and where mental disorders begin and perhaps how to slow or stop ...

  10. Brain Basics

    Medline Plus

    Full Text Available ... and are working to compare that with brain development in people mental disorders. Genes and environmental cues both help to direct ... as they grow there are differences in brain development in children who develop bipolar disorder than children who do not. Studies comparing such ...

  11. Brain Basics

    Medline Plus

    Full Text Available ... her symptoms were not caused by a stroke, brain tumor, or similar conditions, Sarah's doctor referred her to a psychiatrist, a type of medical doctor who is an expert on mental ... of serotonin in the brain and help reduce symptoms of depression. Sarah also ...

  12. Brain Basics

    Medline Plus

    Full Text Available ... the brain, which is linked to thought and emotion. It is also linked to reward systems in the brain. Problems in producing dopamine can result in Parkinson's disease, a disorder that affects a person's ability to move as they want to, resulting ...

  13. Brain imaging

    International Nuclear Information System (INIS)

    The techniques of brain imaging and results in perfusion studies and delayed images are outlined. An analysis of the advantages and disadvantages of the brain scan in a variety of common problems is discussed, especially as compared with other available procedures. Both nonneoplastic and neoplastic lesions are considered. (Auth/C.F.)

  14. Brain Basics

    Medline Plus

    Full Text Available ... will fire. This enhances the electrical flow among brain cells required for normal function and plays an important ... of neurons and their interconnections. neuron —A nerve cell that is the basic, working unit of the brain and nervous system, which processes and transmits information. ...

  15. Brain surgery

    Science.gov (United States)

    ... piece of tumor for a biopsy Remove abnormal brain tissue Drain blood or an infection Free a nerve The bone flap is usually replaced after surgery, using small metal ... or if the brain was swollen. (This is called a craniectomy.) The ...

  16. Brain Basics

    Medline Plus

    Full Text Available ... little dopamine or problems using dopamine in the thinking and feeling regions of the brain may play ... axis —A brain-body circuit which plays a critical role in the body's response to stress. impulse — ...

  17. Brain Basics

    Medline Plus

    Full Text Available ... Basics in Real Life Brain Basics in Real Life—How Depression affects the Brain Meet Sarah Sarah is a middle-aged woman who seemed to have it all. She was happily married and successful in business. Then, after a serious setback at work, she lost interest ...

  18. Brain Basics

    Medline Plus

    Full Text Available ... Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take pictures of ... to slow or stop them from progressing. Functional magnetic resonance imaging (fMRI) is another important research tool in understanding ...

  19. Brain Basics

    Medline Plus

    Full Text Available ... Basics in Real Life Brain Basics in Real Life—How Depression affects the Brain Meet Sarah Sarah is a ... medical history. Epigenetic changes from stress or early-life experiences ... In contrast, major depression is a serious disorder that lasts for weeks. ...

  20. Brain Basics

    Medline Plus

    Full Text Available ... her feelings. Brain Research Modern research tools and techniques are giving scientists a more detailed understanding of the brain than ... a person responds to a certain medication. This information may someday ... is allowing scientists to make important discoveries that could change the ...

  1. Brain Diseases

    Science.gov (United States)

    ... know what causes some brain diseases, such as Alzheimer's disease. The symptoms of brain diseases vary widely depending on the specific problem. In some cases, damage is permanent. In other cases, treatments such as surgery, medicines, or physical therapy can correct the source of the problem or ...

  2. Dark matter, Mach's ether and the QCD vacuum

    CERN Document Server

    Cohen-Tannoudji, Gilles

    2015-01-01

    Here is proposed the idea of linking the dark matter issue, (considered as a major problem of contemporary research in physics) with two other open theoretical questions, one, almost centenary about the existence of an unavoidable ether in general relativity agreeing with the Mach's principle, and one more recent about the properties of the quantum vacuum of the quantum field theory of strong interactions, QuantumChromodynamics (QCD). According to this idea, on the one hand, dark matter and dark energy that, according to the current standard model of cosmology represent about 95% of the universe content, can be considered as two distinct forms of the Mach's ether, and, on the other hand, dark matter, as a perfect fluid emerging from the QCD vacuum could be modeled as a Bose Einstein condensate.

  3. Intrinsic Kinetics of Dimethyl Ether Synthesis from Syngas

    Institute of Scientific and Technical Information of China (English)

    Zhaoguang Nie; Hongwei Liu; Dianhua Liu; Weiyong Ying; Dingye Fang

    2005-01-01

    The intrinsic kinetics of dimethyl ether (DME) synthesis from syngas over a methanol synthesis catalyst mixed with methanol dehydration catalyst has been investigated in a tubular integral reactor at 3-7 MPa and 220-260 ℃. The three reactions including methanol synthesis from CO and H2, CO2 and H2, and methanol dehydration were chosen as the independent reactions. The L-H kinetic model was presented for dimethyl ether synthesis and the parameters of the model were obtained by using simplex method combined with genetic algorithm. The model is reliable according to statistical analysis and residual error analysis. The synergy effect of the reactions over the bifunctional catalyst was compared with the effect for methanol synthesis catalyst under the same conditions based on the model. The effects of syngas containing N2 on the reactions were also simulated.

  4. SYNTHESIS OF ALLYL PHENYL ETHER AND CLAISEN REARRANGEMENT

    Directory of Open Access Journals (Sweden)

    Gagik Torosyan

    2011-12-01

    Full Text Available It has been established the possibility for phenol allylation on natural zeolites and them analogs. Here is demonstrated the synthesis of allyl phenol, which has wide industrial applications. The offered method in comparison with the traditional methods has more advantages – higher selectivity, smaller material and power resources consumption. It has been obtained the mixture of allylating phenols (30% in general with allyl phenyl ether (1 with 80% yields. At 600 K is obtained allylphenyl ether, at 700 K beginning the formation of allyl phenols, which is the result of direct C-allylation of the aromatic ring. It has been investigated the possibility of Claisen rearrangement in the same conditions. All of that are established by gas-liquid chromatography and liquid chromatography data.

  5. Numerical investigation on the effect of injection pressure on the internal flow characteristics for diethyl ether, dimethyl ether and diesel fuel injectors using CFD

    Directory of Open Access Journals (Sweden)

    Vijayakumar Thulasi

    2011-01-01

    Full Text Available The spray characteristics of the diesel fuel are greatly affected by the cavitation formed inside the injector due to the high pressure differential across the nozzle. Many researchers across the globe are exploring the potential of using diethyl ether and dimethyl ether as an alternate for diesel fuel to meet the strict emission norms. Due to the variation in the fuel properties the internal flow characteristics in injectors for ether fuels are expected to be different from that of the diesel fuel. In this paper computational technique is used to study and compare the internal flow characteristics of diethyl ether, dimethyl ether and diesel fuel. The two phase flow model considering the fuel as a mixture of liquid and vapor is adopted for the simulation study. The injection pressure is varied from 100 to 400 bar and the flow characteristics of all three fuels are simulated and compared. Results indicate that all three fuels have distinct cavitating patterns owing to different property values. The dimethyl ether is found to be more cavitating than diesel and diethyl ether fuels as expected. The mass of fuel injected are found to be decreasing for the ether fuels when compared with diesel fuel at all injection pressures.

  6. Synthesis and adsorption properties of chitosan-crown ether resins

    Institute of Scientific and Technical Information of China (English)

    彭长宏; 陈艺锋; 唐谟堂

    2003-01-01

    Two kinds of novel chitosan-crown ether resins, Schiff base type chitosan-benzo-15-crown-5 (CTS-B15)and chitosan-benzo-18-crown-6 (CTS-B18), were synthesized through the reaction between -NH2 in chitosan and -CHO in 4′-formyl benzo-crown ethers. Their structures were characterized by elemental analysis and FT-IR spectra analysis. The elemental analysis results show that the mass fractions of nitrogen in CTS-B15 and CTS-B18 are much lower than those of chitosan. The results of FT-IR spectra of CTS-B15 and CTS-B18 reveal that there exist characteristic peak of C= N, N-H and Ar, and characteristic peak of pyr anoside in the chain of chitosan-crown ether resins, showing that the structures of chitosan-crown ethers are as expected. The adsorption properties of CTS-B15 and CTS-B18 for Pd2+ , Cu2 + and Hg2+ were studied and the experimental results show that these adsorbents have both good adsorption characterization and especially high particular adsorption selectivity for Pd2+ when Cu2+ and Hg2+ are in coexistence, and the coefficients of selectivity of CTS-B15 and CTS-B18 for metal ions are KPd2+/cu2+ =7.56, KPd2+/Hg2+ = 68.00, Kcu2+/Hg2+ = 9.00 and KPd2+/cu2+ = 6.00, KPd2+/Hg2+ = 19. 00, Kcu2+/Hg2+ = 3.00, respectively.

  7. Photodissociation of Non-Covalent Peptide-Crown Ether Complexes

    OpenAIRE

    Wilson, Jeffrey J.; Kirkovits, Gregory J.; Sessler, Jonathan L.; Brodbelt, Jennifer S.

    2007-01-01

    Highly chromogenic 18-crown-6-dipyrrolylquinoxaline coordinates primary amines of peptides, forming non-covalent complexes that can be transferred to the gas phase by electrospray ionization. The appended chromogenic crown ether facilitates efficient energy transfer to the peptide upon ultraviolet irradiation in the gas phase, resulting in diagnostic peptide fragmentation. Collisional activated dissociation (CAD) and infrared multiphoton dissociation (IRMPD) of these non-covalent complexes re...

  8. Detonation characteristics of dimethyl ether and ethanol-air mixtures

    Science.gov (United States)

    Diakow, P.; Cross, M.; Ciccarelli, G.

    2015-05-01

    The detonation cell structure in dimethyl ether vapor and ethanol vapor-air mixtures was measured at atmospheric pressure and initial temperatures in the range of 293-373 K. Tests were carried out in a 6.2-m-long, 10-cm inner diameter tube. For more reactive mixtures, a series of orifice plates were used to promote deflagration-to-detonation transition in the first half of the tube. For less reactive mixtures prompt detonation initiation was achieved with an acetylene-oxygen driver. The soot foil technique was used to capture the detonation cell structure. The measured cell size was compared to the calculated one-dimensional detonation reaction zone length. For fuel-rich dimethyl ether mixtures the calculated reaction zone is highlighted by a temperature gradient profile with two maxima, i.e., double heat release. The detonation cell structure was interpreted as having two characteristic sizes over the full range of mixture compositions. For mixtures at the detonation propagation limits the large cellular structure approached a single-head spin, and the smaller cells approached the size of the tube diameter. There is little evidence to support the idea that the two cell sizes observed on the foils are related to the double heat release predicted for the rich mixtures. There was very little influence of initial temperature on the cell size over the temperature range investigated. A double heat release zone was not predicted for ethanol-air detonations. The detonation cell size for stoichiometric ethanol-air was found to be similar to the size of the small cells for dimethyl ether. The measured cell size for ethanol-air did not vary much with composition in the range of 30-40 mm. For mixtures near stoichiometric it was difficult to discern multiple cell sizes. However, near the detonation limits there was strong evidence of a larger cell structure similar to that observed in dimethyl ether air mixtures.

  9. The epistemic view of quantum states and the ether

    CERN Document Server

    Marchildon, L

    2005-01-01

    The idea that the wave function represents information, or knowledge, rather than the state of a microscopic object has been held to solve foundational problems of quantum mechanics. Realist interpretation schemes, like Bohmian trajectories, have been compared to the ether in pre-relativistic theories. I argue that the comparison is inadequate, and that the epistemic view of quantum states begs the question of interpretation.

  10. Synthesis of active nitroguaiacol ether derivatives of streptomycin.

    OpenAIRE

    Abad, J P; Amils, R.

    1990-01-01

    The synthesis, purification, and biological properties of nitroguaiacol ether derivatives of streptomycin and their corresponding radioactive reduced products were examined. These derivatives are biologically active against gram-positive and gram-negative eubacteria and they are also photoreactive because of the presence of the nitroguaiacol group in the molecule. We demonstrated that these derivatives can be used as streptomycin analogs in photoaffinity labeling of the macromolecular structu...

  11. Glycerol ether lipids in sediments: sources, diversity and implications

    OpenAIRE

    Liu, Xiao-Lei

    2011-01-01

    Glycerol ether lipids are prominent membrane constituents in Archaea and Bacteria that are characterized by high potential for preservation in geological settings.During the past decade they were increasingly used in molecular proxies. For example,selected glycerol dialkyl glycerol tetraethers (GDGT) are used in ratios such as the TEX86 and BIT index for reconstructing past sea surface temperature (SST) and terrestrial input, respectively. However, the distribution and structural diversity of...

  12. Study on Synergy Effect in Dimethyl Ether Synthesis from Syngas

    Institute of Scientific and Technical Information of China (English)

    王志良; 刁杰; 王金福; 金涌

    2001-01-01

    Influence of reaction temperature, pressure and space velocity on the direct synthesis of dimethyl ether (DME) from syngas is studied in an isothermal fixed-bed reactor. The catalyst is a physical mixture of C30 copper-based methanol (MeOH) synthesis catalyst and ZSM-5 dehydration catalyst. The experimental results show that the chemical synergy between methanol synthesis reaction and methanol dehydration reaction is evident. The conversion of carbon monoxide is over 90%.

  13. Methyltert-butyl Ether (MTBE) Degradation by a Microbial Consortium

    OpenAIRE

    S. B. Mortazavi; A Nikpey; A. Rezaee; H Asilian; A Khavanin; H. Kazemian

    2005-01-01

    Methyl tert-butyl ether (MTBE) is added to reformulated gasoline to meet the 1990 Clean Air Act directives. Widespread use of MTBE in gasoline has resulted in groundwater contamination. Because of its undesirable effects on drinking water and ecologically harmful effects, MTBE removal has become a public health and environmental concern. In this study, we have isolated a mixed bacterial culture which is capable of degrading the MTBE as a sole carbon and energy source. This consortium was deve...

  14. Gravitation as a pressure force: a scalar ether theory

    OpenAIRE

    Arminjon, Mayeul

    2011-01-01

    If the presence of a gravitational field breaks the Lorentz symmetry valid for special relativity, an "absolute motion" might be detectable. We summarize a scalar theory of gravity with a such "ether", which starts from a tentative interpretation of gravity as a pressure force. The theory also admits that our physical standards of space and time are affected by gravitation similarly as they are affected by a uniform motion. General motion is governed by an extension of Newton's second law to ...

  15. Solution of a gallstone with methyl-tertiary butyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Brambs, H.J.; Roeren, T.; Holstege, A.; Raedecke, J.

    1987-08-01

    Methyl-t-butyl ether is a new agent to dissolve gallstones. The substance proves to be very successful and acts very rapidly. A percutaneous transhepatic drainage supplies an adequate access route to dissolve calculi within the bile ducts. We report the case of a patient where before insertion of an internal stent a stone in the common bile duct was dissolved within 3 1/2 hours.

  16. A constitutive model of polyether-ether-ketone (PEEK).

    Science.gov (United States)

    Chen, Fei; Ou, Hengan; Lu, Bin; Long, Hui

    2016-01-01

    A modified Johnson-Cook (JC) model was proposed to describe the flow behaviour of polyether-ether-ketone (PEEK) with the consideration of coupled effects of strain, strain rate and temperature. As compared to traditional JC model, the modified one has better ability to predict the flow behaviour at elevated temperature conditions. In particular, the yield stress was found to be inversely proportional to temperature from the predictions of the proposed model. PMID:26409233

  17. Determination of polybrominated diphenyl ethers in environmental standard reference materials

    Energy Technology Data Exchange (ETDEWEB)

    Stapleton, Heather M.; Schantz, Michele M.; Wise, Stephen A. [National Institute of Standards and Technology, Analytical Chemistry Division, Gaithersburg, MD (United States); Keller, Jennifer M.; Kucklick, John R. [National Institute of Standards and Technology, Analytical Chemistry Division, Hollings Marine Laboratory, Charleston, SC (United States); Leigh, Stefan D. [National Institute of Standards and Technology, Statistical Engineering Division, Gaithersburg, MD (United States)

    2007-04-15

    Standard reference materials (SRMs) are valuable tools in developing and validating analytical methods to improve quality assurance standards. The National Institute of Standards and Technology (NIST) has a long history of providing environmental SRMs with certified concentrations of organic and inorganic contaminants. Here we report on new certified and reference concentrations for 27 polybrominated diphenyl ether (PBDE) congeners in seven different SRMs: cod-liver oil, whale blubber, fish tissue (two materials), mussel tissue and sediment (two materials). PBDEs were measured in these SRMs, with the lowest concentrations measured in mussel tissue (SRM 1974b) and the highest in sediment collected from the New York/New Jersey Waterway (SRM 1944). Comparing the relative PBDE congener concentrations within the samples, we found the biota SRMs contained primarily tetrabrominated and pentabrominated diphenyl ethers, whereas the sediment SRMs contained primarily decabromodiphenyl ether (BDE 209). The cod-liver oil (SRM 1588b) and whale blubber (SRM 1945) materials were also found to contain measurable concentrations of two methoxylated PBDEs (MeO-BDEs). Certified and reference concentrations are reported for 12 PBDE congeners measured in the biota SRMs and reference values are available for two MeO-BDEs. Results from a sediment interlaboratory comparison PBDE exercise are available for the two sediment SRMs (1941b and 1944). (orig.)

  18. Sulfonated Poly(Ether Ether Ketone)/Functionalized Carbon Nanotube Composite Membrane for Vanadium Redox Flow Battery Applications

    International Nuclear Information System (INIS)

    A novel sulfonated poly(ether ether ketone) (SPEEK) membrane embedded with the short-carboxylic multi-walled carbon nanotube (we name it as SPEEK/SCCT membrane) for vanadium redox flow battery (VRB) has been prepared with low capacity loss, low cost and high energy efficiency. The mechanical strength, vanadium ions permeability and performance of the membrane in the VRB single cell were characterized. Results showed that the SPEEK/SCCT membrane possessed low permeability of vanadium ions, accompanied by higher mechanical strength than the Nafion 212 membrane. The VRB single cell with SPEEK/SCCT membrane showed 7% higher coulombic efficiency (CE), 6% higher energy efficiency (EE) but lower capacity loss in comparison with the one with Nafion 212. The good cell performance, low capacity loss and high vanadium ions barrier properties of the blend membrane is of significant interest for VRB applications

  19. Influence of the angle between two crown ether moieties on supramolecular copolymerization of bis(crown ether)s and bisparaquat homoditopic monomers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Bis(crown ether) homoditopic monomers containing two bis(p-phenylene)-34-crown-10 moieties with different angles(180° for monomer 3,120°for monomer 4,and 60°for monomer 5) and a complementary bisparaquat homoditopic monomer(7) were designed and synthesized.The three bis(crown ether) monomers could organize into linear supramolecular polymers in concentrated solutions in CHCl3/CH3CN with the bisparaquat monomer 7,as demonstrated by 1 H NMR and viscosity studies. The pseudorotaxanes or supramolecular polymers formed from 3+7 and 4+7 had larger values of Ka,p,n,slope 1,and slope 2 than those of 5+7.This result was attributed to the greater steric hindrance of compound 5 than that of 3 and 4,which resulted in less effective formation of linear supramolecular polymers from 5 with compound 7 than those from compounds 3 and 4 with compound 7,as also demonstrated by UV-vis method.

  20. Brain tumor

    International Nuclear Information System (INIS)

    BNCT in the past was not widely accepted because of poor usability of a nuclear reactor as a neutron source. Recently, technical advancements in the accelerator field have made accelerator-based BNCT feasible. Consequently, clinical trials of intractable brain tumors have started using it since 2012. In this review, our clinical results obtained from conventional reactor-based BNCT for treatment of brain tumors are introduced. It is strong hope that accelerator-based BNCT becomes a standard therapy for current intractable brain tumors. (author)

  1. Biosorption and degradation of decabromodiphenyl ether by Brevibacillus brevis and the influence of decabromodiphenyl ether on cellular metabolic responses.

    Science.gov (United States)

    Wang, Linlin; Tang, Litao; Wang, Ran; Wang, Xiaoya; Ye, Jinshao; Long, Yan

    2016-03-01

    There is global concern about the effects of decabromodiphenyl ether (BDE209) on environmental and public health. The molecular properties, biosorption, degradation, accumulation, and cellular metabolic effects of BDE209 were investigated in this study to identify the mechanisms involved in the aerobic biodegradation of BDE209. BDE209 is initially absorbed by wall teichoic acid and N-acetylglucosamine side chains in peptidoglycan, and then, BDE209 is transported and debrominated through three pathways, giving tri-, hepta-, octa-, and nona-bromodiphenyl ethers. The C-C bond energies decrease as the number of bromine atoms on the diphenyl decreases. Polybrominated diphenyl ethers (PBDEs) inhibit protein expression or accelerate protein degradation and increase membrane permeability and the release of Cl(-), Na(+), NH4 (+), arabinose, proteins, acetic acid, and oxalic acid. However, PBDEs increase the amounts of K(+), Mg(2+), PO4 (3-), SO4 (2-), and NO3 (-) assimilated. The biosorption, degradation, accumulation, and removal efficiencies when Brevibacillus brevis (1 g L(-1)) was exposed to BDE209 (0.5 mg L(-1)) for 7 days were 7.4, 69.5, 16.3, and 94.6 %, respectively. PMID:26555880

  2. Size-exclusion chromatography of ultrahigh molecular weight methylcellulose ethers and hydroxypropyl methylcellulose ethers for reliable molecular weight distribution characterization.

    Science.gov (United States)

    Li, Yongfu; Shen, Hongwei; Lyons, John W; Sammler, Robert L; Brackhagen, Meinolf; Meunier, David M

    2016-03-15

    Size-exclusion chromatography (SEC) coupled with multi-angle laser light scattering (MALLS) and differential refractive index (DRI) detectors was employed for determination of the molecular weight distributions (MWD) of methylcellulose ethers (MC) and hydroxypropyl methylcellulose ethers (HPMC) having weight-average molecular weights (Mw) ranging from 20 to more than 1,000kg/mol. In comparison to previous work involving right-angle light scattering (RALS) and a viscometer for MWD characterization of MC and HPMC, MALLS yields more reliable molecular weight for materials having weight-average molecular weights (Mw) exceeding about 300kg/mol. A non-ideal SEC separation was observed for cellulose ethers with Mw>800kg/mol, and was manifested by upward divergence of logM vs. elution volume (EV) at larger elution volume at typical SEC flow rate such as 1.0mL/min. As such, the number-average molecular weight (Mn) determined for the sample was erroneously large and polydispersity (Mw/Mn) was erroneously small. This non-ideality resulting in the late elution of high molecular weight chains could be due to the elongation of polymer chains when experimental conditions yield Deborah numbers (De) exceeding 0.5. Non-idealities were eliminated when sufficiently low flow rates were used. Thus, using carefully selected experimental conditions, SEC coupled with MALLS and DRI can provide reliable MWD characterization of MC and HPMC covering the entire ranges of compositions and molecular weights of commercial interest. PMID:26794765

  3. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Science.gov (United States)

    2010-07-01

    ... polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether. 721.1729 Section 721.1729 Protection... acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene......

  4. Safety Assessment of Alkyl PEG/PPG Ethers as Used in Cosmetics.

    Science.gov (United States)

    Fiume, Monice M; Heldreth, Bart; 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

    2016-07-01

    The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of 131 alkyl polyethylene glycol (PEG)/polypropylene glycol ethers as used in cosmetics, concluding that these ingredients are safe in the present practices of use and concentration described in this safety assessment when formulated to be nonirritating. Most of the alkyl PEG/PPG ethers included in this review are reported to function in cosmetics as surfactants, skin-conditioning agents, and/or emulsifying agents. The alkyl PEG/PPG ethers share very similar physiochemical properties as the alkyl PEG ethers, which were reviewed previously by the CIR Expert Panel and found safe when formulated to be nonirritating. The alkyl PEG ethers differ by the inclusion of PPG repeat units, which are used to fine-tune the surfactant properties of this group. The Panel relied heavily on data on analogous ingredients, extracted from the alkyl PEG ethers and PPG reports, when making its determination of safety. PMID:27383199

  5. Brain and Addiction

    Science.gov (United States)

    ... Teens / Drug Facts / Brain and Addiction Brain and Addiction Print Your Brain Your brain is who you ... is taken over and over. What Is Drug Addiction? Addiction is a chronic brain disease that causes ...

  6. Brain tumor - primary - adults

    Science.gov (United States)

    ... Vestibular schwannoma (acoustic neuroma) - adults; Meningioma - adults; Cancer - brain tumor (adults) ... Primary brain tumors include any tumor that starts in the brain. Primary brain tumors can start from brain cells, ...

  7. Mechanisms of flash pyrolysis of ether lipids isolated from the green microalga Botryococcus braunii race

    OpenAIRE

    Sinninghe Damsté, J.S.; Gelin, F.; Gatellier, J-P.L.A.; Metzger, P.; Derenne, S.; Largeau, C.; Leeuw, J.W. de

    1993-01-01

    Two types of ether lipids isolated from the microalga Botryococcus braunii have been subjected to flash pyrolysis. The pyrolysis products were separated and analyzed by GC/MS. The nature and distribution of the pyrolysis compounds gave clues to the different mechanisms involved in the pyrolysis of ether-linked alkyl chains. The relatively abundant presence of alkenes, alkadienes, alken-9-ones and alken-10-ones with chain lengths corresponding to those of the ether-bound alkyl chains indicated...

  8. Brain Basics

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    Full Text Available ... or serious and cause severe disability. Through research, we know that mental disorders are brain disorders. Evidence ... many different types of cells in the body. We say that cells differentiate as the embryo develops, ...

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    Full Text Available ... bind onto, leading to more normal mood functioning. Dopamine —mainly involved in controlling movement and aiding the ... reward systems in the brain. Problems in producing dopamine can result in Parkinson's disease, a disorder that ...

  13. Brain Basics

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    Full Text Available ... Statistics Help for Mental Illnesses Outreach Outreach Home Public Involvement Outreach Partners Alliance for Research Progress Coalition ... also linked to reward systems in the brain. Problems in producing dopamine can result in Parkinson's disease, ...

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    Full Text Available ... related to changes in the anatomy, physiology, and chemistry of the nervous system. When the brain cannot ... husband questions about Sarah's symptoms and family medical history. Epigenetic changes from stress or early-life experiences ...

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    Full Text Available ... at the front of the brain that, in humans, plays a role in executive functions such as ... to another. Share Science News Connectome Re-Maps Human Cortex ECT Lifts Depression, Sustains Remission in Older ...

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    Full Text Available ... the brain, which is linked to thought and emotion. It is also linked to reward systems in ... stay focused on a task, and managing proper emotional reactions. Reduced ACC activity or damage to this ...

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    Full Text Available ... little dopamine or problems using dopamine in the thinking and feeling regions of the brain may play ... but can still remember past events and learned skills, and carry on a conversation, all which rely ...

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    Full Text Available ... for the function of conducting messages. A neuron has three basic parts: Cell body which includes the ... disorder (ADHD) . Glutamate —the most common neurotransmitter, glutamate has many roles throughout the brain and nervous system. ...

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    Full Text Available ... he saw, Sarah's husband took her to the doctor, who ran some tests. After deciding her symptoms ... a stroke, brain tumor, or similar conditions, Sarah's doctor referred her to a psychiatrist, a type of ...

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    Full Text Available ... producing dopamine can result in Parkinson's disease, a disorder that affects a person's ability to move as they want ... the brain. The hippocampus may be involved in mood disorders through its control of a major mood circuit ...

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    Full Text Available ... of the brain's executive functions, such as judgment, decision making, and problem solving. Different parts of the PFC ... a role in executive functions such as judgment, decision making and problem solving, as well as emotional control ...

  5. Brain Basics

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    Full Text Available ... related to changes in the anatomy, physiology, and chemistry of the nervous system. When the brain cannot ... NIMH Strategic Plan in 2016 August 31, 2016, 2:00-3:00 PM ET General Health Information ...

  6. Brain Basics

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    Full Text Available ... sends impulses and extends from cell bodies to meet and deliver impulses to another nerve cell. Axons ... in Real Life—How Depression affects the Brain Meet Sarah Sarah is a middle-aged woman who ...

  7. Brain Basics

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    Full Text Available ... Alliance for Research Progress Coalition for Research Progress Legislative Activities Research Priorities Research Priorities Home Research Areas ... of the brain's executive functions, such as judgment, decision making, and problem solving. Different parts of the ...

  8. Brain Basics

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    Full Text Available ... These circuits control specific body functions such as sleep and speech. The brain continues maturing well into ... factors that can affect our bodies, such as sleep, diet, or stress. These factors may act alone ...

  9. Brain Basics

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    Full Text Available ... each other How changes in the brain can lead to mental disorders, such as depression. The Growing ... understanding of genes and epigenetics may one day lead to genetic testing for people at risk for ...

  10. Brain Health

    Science.gov (United States)

    ... Love Your Brain Stay Physically Active Adopt a Healthy Diet Stay Mentally and Socially Active We Can Help ... of any wellness plan. Learn More Adopt a Healthy Diet > Eat a heart-healthy diet that benefits both ...

  11. Brain Basics

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    Full Text Available ... Offices and Divisions Careers@NIMH Advisory Boards and Groups Staff Directories Getting to NIMH National Institutes of ... electrical signals. The brain begins as a small group of cells in the outer layer of a ...

  12. Brain Basics

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    Full Text Available ... illnesses, such as depression, can occur when this process does not work correctly. Communication between neurons can also be electrical, such as in areas of the brain that control movement. When electrical signals are abnormal, they can ...

  13. Brain Basics

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    Full Text Available ... they can cause tremors or symptoms found in Parkinson's disease. Serotonin —helps control many functions, such as ... brain. Problems in producing dopamine can result in Parkinson's disease, a disorder that affects a person's ability ...

  14. Brain Basics

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    Full Text Available ... magnetic fields to take pictures of the brain's structure. mutation —A change in the code for a gene, which may be harmless or even helpful, but sometimes give rise to disabilities or diseases. neural ...

  15. Brain Basics

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    Full Text Available ... as sleep and speech. The brain continues maturing well into a person's early 20s. Knowing how the ... as judgment, decision making and problem solving, as well as emotional control and memory. serotonin —A neurotransmitter ...

  16. Brain Basics

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    Full Text Available ... mental disorder, or perhaps you have experienced one yourself at some point. Such disorders include depression , anxiety ... control specific body functions such as sleep and speech. The brain continues maturing well into a person's ...

  17. Brain Basics

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    Full Text Available ... some point. Such disorders include depression , anxiety disorders , bipolar disorder , attention deficit hyperactivity disorder (ADHD) , and many others. ... differences in brain development in children who develop bipolar disorder than children who do not. Studies comparing such ...

  18. Brain Basics

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    Full Text Available ... can diagnose mental disorders are psychologists or clinical social workers. The psychiatrist asked Sarah and her husband ... the understanding of how the brain grows and works and the effects of genes and environment on ...

  19. Brain Basics

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    Full Text Available ... illnesses are disorders of the brain, and ongoing research that helps us better understand and treat disorders. Mental disorders are common. You may have a friend, colleague, or relative with a mental disorder, or ...

  20. Brain Basics

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    Full Text Available ... they can be related to changes in the anatomy, physiology, and chemistry of the nervous system. When the brain cannot effectively coordinate the billions of cells in the body, the results can affect many aspects of life. ...

  1. Brain Basics

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    Full Text Available ... of the brain's executive functions, such as judgment, decision making, and problem solving. Different parts of the ... a role in executive functions such as judgment, decision making and problem solving, as well as emotional ...

  2. Brain Basics

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    Full Text Available ... genes and epigenetics may one day lead to genetic testing for people at risk for mental disorders. ... brain. DNA —The "recipe of life," containing inherited genetic information that helps to define physical and some ...

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    Full Text Available ... in early detection, more tailored treatments, and possibly prevention of such illnesses. The Working Brain Neurotransmitters Everything ... Severe Irritability, 12-1:00 PM ET National Prevention Week May 15-21, 2016 General Health Information ...

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    Full Text Available ... of the cell from its surrounding environment and controls what enters and leaves the cell, and responds ... via axons) to form brain circuits. These circuits control specific body functions such as sleep and speech. ...

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    Full Text Available ... interconnections. neuron —A nerve cell that is the basic, working unit of the brain and nervous system, which processes and transmits information. neurotransmitter —A chemical produced by ...

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    Full Text Available ... may help improve treatments for anxiety disorders like phobias or post-traumatic stress disorder (PTSD) . Prefrontal cortex ( ... doctor, who ran some tests. After deciding her symptoms were not caused by a stroke, brain tumor, ...

  8. Brain Basics

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    Full Text Available ... some point. Such disorders include depression , anxiety disorders , bipolar disorder , attention deficit hyperactivity disorder (ADHD) , and many ... differences in brain development in children who develop bipolar disorder than children who do not. Studies comparing ...

  9. Brain Basics

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  13. Brain Basics

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  14. Brain imaging and brain function

    International Nuclear Information System (INIS)

    This book is a survey of the applications of imaging studies of regional cerebral blood flow and metabolism to the investigation of neurological and psychiatric disorders. Contributors review imaging techniques and strategies for measuring regional cerebral blood flow and metabolism, for mapping functional neural systems, and for imaging normal brain functions. They then examine the applications of brain imaging techniques to the study of such neurological and psychiatric disorders as: cerebral ischemia; convulsive disorders; cerebral tumors; Huntington's disease; Alzheimer's disease; depression and other mood disorders. A state-of-the-art report on magnetic resonance imaging of the brain and central nervous system rounds out the book's coverage

  15. Synthesis and characterization of quaternized poly(phthalazinone ether sulfone ketone) for anion-exchange membrane

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chloromethylated poly(phthalazinone ether sulfone ketone) (CMPPESK) was prepared from poly(phthalazinone ether sulfone ketone) (PPESK) using chloromethyl octyl ethers (CMOE) with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc) and chloroform. Quatemized poly(phthalazinone ether sulfone ketone) (QAPPESK) was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance,which was only partly soluble in sulfuric acid (98%) and swollen in N,N-dimethylformamide (DMF). The vanadium redox flow battery (V-RFB) using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.

  16. AIRBORNE POLYBROMINATED DIPHENYL ETHERS IN A COMPUTER CLASSROOM OF COLLEGE IN TAIWAN

    Directory of Open Access Journals (Sweden)

    F. H. Chang ، C. R. Yang ، C. Y. Tsai ، W. C. Lin

    2009-04-01

    Full Text Available This study characterized the airborne exposure of students to thirty polybrominated diphenyl ether congeners inside and outside a computer classroom in a southern Taiwan college. Arithmetic mean values of total indoor and outdoor polybrominated diphenyl ether concentrations were 125.0 pg/m3 (89.8 to 203.9 pg/m3 and 110.3 pg/m3 (83.5 to 157.0 pg/m3, respectively. Total indoor polybrominated diphenyl ether concentrations were one order of magnitude lower than those detected in homes in Birmingham, United Kingdom and in Ottawa, Canada but were several times higher than those measured in the ambient air in Ottawa, Canada and from the Bohai Sea to the Arctic. The five highest indoor concentrations of polybrominated diphenyl ether congeners were decabromodiphenyl ether (23.0 pg/m3, 4,4’-dibromodiphenyl ether (15.9 pg/m3, 2,2’,3,4,4’,5,5’,6-octabromodiphenyl ether (10.6 pg/m3, 2,4-dibromodiphenyl ether (10.3 pg/m3 and 2,2’,3,4,4’,5’,6-heptabromodiphenyl ether (10.0 pg/m3. Although indoor and outdoor total polybrominated diphenyl ether concentrations did not significantly differ, the indoor concentrations of 2,4-dibromodiphenyl ether, 2,2’,4-tribromodiphenyl ether, 2,4,4’-tribromodiphenyl ether, 2,2’,4,5’-tetrabromodiphenyl ether and 2,3’,4’,6-tetrabromodiphenyl ether were significantly higher than their outdoor concentrations. This study suggests the following measures: 1 to increase the air exchange rate and open classroom doors and windows for several minutes before classes to reduce indoor PBDE concentrations; 2 to reduce polybrominated diphenyl ether emissions from new devices, it’s better to use computer-related products that meet the Restriction of Hazardous Substances Directive adopted by the European Union.

  17. Anti-Parkinson Activity of Petroleum Ether Extract of Ficus religiosa (L. Leaves

    Directory of Open Access Journals (Sweden)

    Jitendra O. Bhangale

    2016-01-01

    Full Text Available In the present study, we evaluated anti-Parkinson’s activity of petroleum ether extract of Ficus religiosa (PEFRE leaves in haloperidol and 6 hydroxydopamine (6-OHDA induced experimental animal models. In this study, effects of Ficus religiosa (100, 200, and 400 mg/kg, p.o. were studied using in vivo behavioral parameters like catalepsy, muscle rigidity, and locomotor activity and its effects on neurochemical parameters (MDA, CAT, SOD, and GSH in rats. The experiment was designed by giving haloperidol to induce catalepsy and 6-OHDA to induce Parkinson’s disease-like symptoms. The increased cataleptic scores (induced by haloperidol were significantly (p<0.001 found to be reduced, with the PEFRE at a dose of 200 and 400 mg/kg (p.o.. 6-OHDA significantly induced motor dysfunction (muscle rigidity and hypolocomotion. 6-OHDA administration showed significant increase in lipid peroxidation level and depleted superoxide dismutase, catalase, and reduced glutathione level. Daily administration of PEFRE (400 mg/kg significantly improved motor performance and also significantly attenuated oxidative damage. Thus, the study proved that Ficus religiosa treatment significantly attenuated the motor defects and also protected the brain from oxidative stress.

  18. Anti-Parkinson Activity of Petroleum Ether Extract of Ficus religiosa (L.) Leaves.

    Science.gov (United States)

    Bhangale, Jitendra O; Acharya, Sanjeev R

    2016-01-01

    In the present study, we evaluated anti-Parkinson's activity of petroleum ether extract of Ficus religiosa (PEFRE) leaves in haloperidol and 6 hydroxydopamine (6-OHDA) induced experimental animal models. In this study, effects of Ficus religiosa (100, 200, and 400 mg/kg, p.o.) were studied using in vivo behavioral parameters like catalepsy, muscle rigidity, and locomotor activity and its effects on neurochemical parameters (MDA, CAT, SOD, and GSH) in rats. The experiment was designed by giving haloperidol to induce catalepsy and 6-OHDA to induce Parkinson's disease-like symptoms. The increased cataleptic scores (induced by haloperidol) were significantly (p < 0.001) found to be reduced, with the PEFRE at a dose of 200 and 400 mg/kg (p.o.). 6-OHDA significantly induced motor dysfunction (muscle rigidity and hypolocomotion). 6-OHDA administration showed significant increase in lipid peroxidation level and depleted superoxide dismutase, catalase, and reduced glutathione level. Daily administration of PEFRE (400 mg/kg) significantly improved motor performance and also significantly attenuated oxidative damage. Thus, the study proved that Ficus religiosa treatment significantly attenuated the motor defects and also protected the brain from oxidative stress. PMID:26884755

  19. Microbial degradation of 4-monobrominated diphenyl ether with anaerobic sludge

    International Nuclear Information System (INIS)

    Highlights: ► BDE-3 was degraded with two anaerobes in different rates. ► Glucose addition augment the debromination efficiencies. ► Hydrogen gas was detected and relative microbes were identified. ► Extra-carbon source enhanced degradation partial due to H2-generation bacteria. - Abstract: Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant additives for many plastic and electronic products. Owing to their ubiquitous distribution in the environment, multiple toxicity to humans, and increasing accumulation in the environment, the fate of PBDEs is of serious concern for public safety. In this study, the degradation of 4-monobrominated diphenyl ether (BDE-3) in anaerobic sludge and the effect of carbon source addition were investigated. BDE-3 can be degraded by two different anaerobic sludge samples. The by-products, diphenyl ether (DE) and bromide ions, were monitored, indicating the reaction of debromination within these anaerobic samples. Co-metabolism with glucose facilitated BDE-3 biodegradation in terms of kinetics and efficiency in the Jhongsing sludge. Through the pattern of amplified 16S rRNA gene fragments in denatured gradient gel electrophoresis (DGGE), the composition of the microbial community was analyzed. Most of the predominant microbes were novel species. The fragments enriched in BDE-3-degrading anaerobic sludge samples are presumably Clostridium sp. This enrichment coincides with the H2 gas generation and the facilitation of debromination during the degradation process. Findings of this study provide better understanding of the biodegradation of brominated DEs and can facilitate the prediction of the fate of PBDEs in the environment.

  20. On the radiation stability of crown ethers in ionic liquids.

    Energy Technology Data Exchange (ETDEWEB)

    Shkrob, I.; Marin, T.; Dietz, M. (Chemical Sciences and Engineering Division); (Benedictine Univ.); (Univ. of Wisconsin at Milwaukee)

    2011-04-14

    Crown ethers (CEs) are macrocyclic ionophores used for the separation of strontium-90 from acidic nuclear waste streams. Room temperature ionic liquids (ILs) are presently being considered as replacements for traditional molecular solvents employed in such separations. It is desirable that the extraction efficacy obtained with such solvents should not deteriorate in the strong radiation fields generated by decaying radionuclides. This deterioration will depend on the extent of radiation damage to both the IL solvent and the CE solute. While radiation damage to ILs has been extensively studied, the issue of the radiation stability of crown ethers, particularly in an IL matrix, has not been adequately addressed. With this in mind, we have employed electron paramagnetic resonance (EPR) spectroscopy to study the formation of CE-related radicals in the radiolysis of selected CEs in ILs incorporating aromatic (imidazolium and pyridinium) cations. The crown ethers have been found to yield primarily hydrogen loss radicals, H atoms, and the formyl radical. In the low-dose regime, the relative yield of these radicals increases linearly with the mole fraction of the solute, suggesting negligible transfer of the excitation energy from the solvent to the solute; that is, the solvent has a 'radioprotective' effect. The damage to the CE in the loading region of practical interest is relatively low. Under such conditions, the main chemical pathway leading to decreased extraction performance is protonation of the macrocycle. At high radiation doses, sufficient to increase the acidity of the IL solvent significantly, such proton complexes compete with the solvent cations as electron traps. In this regime, the CEs will rapidly degrade as the result of H abstraction from the CE ring by the released H atoms. Thus, the radiation dose to which a CE/IL system is exposed must be maintained at a level sufficiently low to avoid this regime.

  1. The Microwave Spectrum of Partially Deuterated Species of Dimethyl Ether

    Science.gov (United States)

    Lauvergnat, D.; Margulès, L.; Motiyenko, R. A.; Guillemin, J.-C.; Coudert, L. H.

    2011-06-01

    Dimethyl ether is a molecule of astrophysical interest spectroscopically well characterized. It is one of the simplest molecules with two methyl groups undergoing large amplitude internal rotations. Due to deuterium enrichment in the interstellar medium, one can reasonably expect that partially deuterated species of dimethyl ether might be detected. However, there are no spectroscopic results about the microwave spectrum of such species. A theoretical calculation of the rotation-torsion energy levels of the partially deuterated species of dimethyl ether has been undertaken aided by ab initio calculations. The approach accounts for the complicated torsion-rotation interactions displayed by this molecule and for the fact that deuteration leads to changes of the bidimensional internal rotation effective potential energy surface. Due to zero-point energy contributions from the 19 small amplitude vibrational modes, this surface no longer displays G36 symmetry. Rotation-torsion energy levels are computed treating the two angles of internal rotation as active coordinates and evaluating Hamiltonian matrix elements with the help of Gaussian quadrature. It is hoped that the present results will allow us to understand the microwave spectrum of the mono deuterated species CH_2DOCH_3 which has been recorded in Lille with the new sub millimeter wave spectrometer (150--950 GHz) based on harmonic generation of solid-state sources. [2] Snyder, Buhl, and Schwartz, Astrophys. J. Letters 191 (1974) L79. [3] Endres, Drouin, Pearson, Müller, Lewen, Schlemmer, and Giesen, A&A 504 (2009) 635. [4] Solomon and Woolf, Astrophys. J. Letters 180 (1973) L89. [5] Lauvergnat and Nauts, J. Chem. Phys. 116 (2002) 8560; and Light and Bačić, J. Chem. Phys. 87 (1987) 4008.

  2. Equimolar carbon dioxide absorption by ether functionalized imidazolium ionic liquids

    International Nuclear Information System (INIS)

    A series [C3Omim][X] of imidazolium cation-based ILs, with ether functional group on the alkyl side-chain have been synthesized and structure of the materials were confirmed by various techniques like 1H, 13C NMR spectroscopy, MS-ESI, FTIR spectroscopy and EA. More specifically, the influence of changing the anion with same cation is carried out. The absorption capacity of CO2 for ILs were evaluated at 30 and 50 .deg. C at ambient pressure (0-1.6 bar). Ether functionalized ILs shows significantly high absorption capacity for CO2. In general, the CO2 absorption capacity of ILs increased with a rise in pressure and decreased when temperature was raised. The obtained results showed that absorption capacity reached about 0.9 mol CO2 per mol of IL at 30 .deg. C. The most probable mechanism of interaction of CO2 with ILs were investigated using FTIR spectroscopy, 13C NMR spectroscopy and result shows that the absorption of CO2 in ether functionalized ILs is a chemical process. The CO2 absorption results and detailed study indicates the predominance of 1:1 mechanism, where the CO2 reacts with one IL to form a carbamic acid. The CO2 absorption capacity of ILs for different anions follows the trend: BF4 6 2N. Moreover, the as-synthesized ILs is selective, thermally stable, long life operational and can be recycled at a temperature of 70 .deg. C or under vacuum and can be used repeatedly

  3. CATALYSTS FOR HIGH CETANE ETHERS AS DIESEL FUELS

    Energy Technology Data Exchange (ETDEWEB)

    Kamil Klier; Richard G. Herman; Heock-Hoi Kwon; James G. C. Shen; Qisheng Ma; Robert A. Hunsicker; Andrew P. Butler; Scott J. Bollinger

    2003-03-01

    A tungstena-zirconia (WZ) catalyst has been investigated for coupling methanol and isobutanol to unsymmetrical ethers, i.e. methyl isobutyl ether (MIBE) and compared with earlier studied sulfated-zirconia (SZ) and Nafion-H catalysts. In all cases, the ether synthesis mechanism is a dual site S{sub N}2 process involving competitive adsorption of reactants on proximal acid sites. At low reaction temperatures, methylisobutylether (MIBE) is the predominant product. However, at temperatures >135 C the WZ catalyst is very good for dehydration of isobutanol to isobutene. The surface acid sites of the WZ catalyst and a Nafion-H catalyst were diagnosed by high resolution X-ray photoelectron spectroscopy (XPS) of N 1s shifts after adsorption of amines. Using pyridine, ethylenediamine, and triethylamine, it is shown that WZ has heterogeneous strong Broensted acid sites. Theoretical study located the transition state of the alcohol coupling reaction on proximal Broensted acid sites and accounted well for XPS core-level shifts upon surface acid-base interactions. While computations have not been carried out with WZ, it is shown that the SZ catalyst is a slightly stronger acid than CF{sub 3}SO{sub 3}H (a model for Nafion-H) by 1.3-1.4 kcal/mol. A novel sulfated zirconia catalyst having proximal strong Broensted acid sites was synthesized and shown to have significantly enhanced activity and high selectivity in producing MIBE or isobutene from methanol/isobutanol mixtures. The catalyst was prepared by anchoring 1,2-ethanediol bis(hydrogen sulfate) salt precursor onto zirconium hydroxide, followed by calcination to remove the -(CH{sub 2}CH{sub 2})- bridging residues.

  4. Performance and emission characteristics of QHCCI dimethyl ether engine

    Institute of Scientific and Technical Information of China (English)

    Ying WANG; Wei LI; Tiegang HU; Longbao ZHOU; Shenghua LIU

    2008-01-01

    Experimental investigation into the effects of different pilot amounts of dimethyl ether (DME) on the performance and emission of a single-cylinder direct-injection DME engine is conducted. The results show that a DME engine can operate at a wider range of speeds and loads at quasi-homogenous charge compression ignition (QHCCI) mode. The brake thermal efficiency increases while the exhaust temperature decreases. NOx emission decreases by about 30%-50% although there is a slight increase in HC and CO emissions. NOx, HC and CO emissions increase with an increase in the amount of DME pilot. QHCCI is a good way to increase thermal efficiency and decrease NOx emission.

  5. Direct dimethyl ether high temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Vassiliev, Anton; Jensen, Jens Oluf; Li, Qingfeng;

    A high temperature polybenzimidazole (PBI) polymer fuel cell was fed with dimethyl ether (DME) and water vapour mixture on the anode at ambient pressure with air as oxidant. A peak power density of 79 mW/cm2 was achieved at 200°C. A conventional polymer based direct DME fuel cell is liquid fed and...... suffers from low DME solubility in water. When the DME - water mixture is fed as vapour miscibility is no longer a problem. The increased temperature is more beneficial for the kinetics of the direct oxidation of DME than of methanol. The Open Circuit Voltage (OCV) with DME operation was 50 to 100 m...

  6. Dimethyl ether in diesel engines - progress and perspectives

    DEFF Research Database (Denmark)

    Sorenson, Spencer C

    2001-01-01

    aspects are discussed A simplified theoretical explanation of the emissions behavior of DME is presented A discussion is presented proposing DME as a significant factor in the future international energy picture. Dire to its beneficial combustion properties, possibility of production from a variety of......A review of recent developments related to the use of dimethyl ether (DME) in engines is presented Research work discussed is in the areas of engine performance and emissions, fuel injection systems, spray and ignition delay, and detailed chemical kinetic modeling. DME's properties and safety...

  7. Catalytic Dealkylation of Ethers to Alcohols on Metal Surfaces.

    Science.gov (United States)

    Yang, Biao; Lin, Haiping; Miao, Kangjian; Zhu, Pan; Liang, Liangbo; Sun, Kewei; Zhang, Haiming; Fan, Jian; Meunier, Vincent; Li, Youyong; Li, Qing; Chi, Lifeng

    2016-08-16

    On-surface synthesis has prompted much interest in recent years because it provides an alternative strategy for controlling chemical reactions and allows for the direct observation of reaction pathways. Herein, we combined scanning tunneling microscopy and density functional theory to provide extensive evidence for the conversion of alkoxybenzene-containing ethers into alcohols by means of surface synthesis. The reported dealkylation reactions are finely controlled by the annealing parameters, which govern the onset of successive alkyl chains dissociations. Moreover, density functional theory calculations elucidate the details of the reaction pathways, showing that dealkylation reactions are surface-assisted and very different from their homogeneous analogues in solution. PMID:27432690

  8. Photochemical Degradation of Polybrominated Diphenyl Ethers in Microreactor

    Czech Academy of Sciences Publication Activity Database

    Vajglová, Zuzana; Veselý, M.; Hejda, S.; Vondráčková, Magdalena; Křišťál, Jiří; Cajthaml, Tomáš; Křesinová, Zdena; Tříska, Jan; Klusoň, Petr; Jiřičný, Vladimír

    2015-01-01

    Roč. 41, č. 12 (2015), s. 9373-9381. ISSN 0922-6168. [Pannonian Symposium on Catalysis /12./. Castle Trest, 16.09.2014-20.09.2014] R&D Projects: GA ČR(CZ) GAP105/12/0664; GA ČR GA104/09/0880 Institutional support: RVO:67985858 ; RVO:61388971 ; RVO:67179843 Keywords : polybrominated diphenyl ethers * photochemical microreactor * debromination * photo degradation Subject RIV: CI - Industrial Chemistry, Chemical Engineering; EH - Ecology, Behaviour (UEK-B) Impact factor: 1.221, year: 2014

  9. Isotope effects of zinc in crown ether chromatography

    International Nuclear Information System (INIS)

    Isotope separation of zinc has been studied with a polymer-supported crown ether resin packed in glass columns. Chromatography was performed in a break-through manner by feeding a zinc chloride solution into the columns. The mass analysis revealed that the heavier isotope was enriched at the front part of the zinc adsorption band. This result means that the heavier isotopes are preferentially fractionated into the solution phase. The largest single-stage separation coefficient (ε) in the present work is 1.0 x 10-3 for the isotopic pair of 64Zn and 66Zn at 35degC. (author)

  10. Synthesis and tentative identification of novel polybrominated diphenyl ether metabolites in human blood.

    Science.gov (United States)

    Rydén, Andreas; Nestor, Gustav; Jakobsson, Kristina; Marsh, Göran

    2012-08-01

    Hydroxylated polybrominated diphenyl ethers (OH-PDBEs) are exogenous, bioactive compounds that originate, to a large extent, from anthropogenic activities, although they are also naturally produced in the environment. In the present study nine new authentic OH-PBDE reference standards and their corresponding methyl ether derivatives (MeO-PBDEs) were synthesised and characterised by NMR spectroscopy and mass spectrometry. Seven of the authentic reference standards prepared were thereafter tentatively identified in a pooled human blood sample. The tentatively identified OH-PBDEs were 3-hydroxy-2,2',4,4',6-pentabromodiphenyl ether, 3'-hydroxy-2,2',4,4',6-pentabromodiphenyl ether, 3-hydroxy-2,2',4,4',5-pentabromodiphenyl ether, 3-hydroxy-2,2',4,4',5,6'-hexabromodiphenyl ether, 3'-hydroxy-2,2',4,4',5,6'-hexabromodiphenyl ether, 3-hydroxy-2,2',4,4',5,5'-hexabromodiphenyl ether and 4-hydroxy-2,2',3,4',5,5',6-heptabromodiphenyl ether. An additional seven OH-PBDEs were tentatively identified in the pooled human blood sample, of which one OH-PBDE, 4'-hydroxy-2,2',4,5,5'-pentabromodiphenyl ether, has not been identified in human blood before. The identification was performed using gas chromatography-mass spectrometry (GC-MS) recording the bromine ions m/z 79, 81. The tentative identification was supported by the peaks relative retention times (RRTs) compared to authentic references on two GC columns of different polarities for the hexa-, and heptabrominated OH-PBDEs, and three different GC columns for the pentabrominated OH-PBDEs. The OH-PBDE congeners most likely originate from human metabolism of a flame retardant, i.e. polybrominated diphenyl ethers (PBDEs), due to the relatively high concentrations of PBDEs in the same human blood sample and the fact that these PBDEs could form the tentatively identified OH-PBDEs via metabolic direct hydroxylation or via 1,2-shift. PMID:22572169

  11. Brain SPECT

    International Nuclear Information System (INIS)

    Brain SPECT investigations have gained broad acceptance since the introduction of the lipophilic tracer Tc-99m-HMPAO. Depending on equipment and objectives in different departments, the examinations can be divided into three groups: 1. Under normal conditions and standardised patient preparation the 'rest' SPECT can be performed in every department with a tomographic camera. In cerebrovascular disease there is a demand for determination of either the perfusion reserve in reversible ischemia or prognostic values in completed stroke. In cases of dementia, SPECT may yield useful results according to differential diagnosis. Central cerebral system involvement in immunologic disease may be estimated with higher sensitivity than in conventional brain imaging procedures. In psychiatric diseases there is only a relative indication for brain SPECT, since results during recent years have been contradictory and may be derived only in interventional manner. In brain tumor diagnostics SPECT with Tl-201 possibly permits grading. In inflammatory disease, especially in viral encephalitis, SPECT may be used to obtain early diagnosis. Normal pressure hydrocephalus can be distinguished from other forms of dementia and, consequently, the necessity for shunting surgery can be recognised. 2. In departments equipped for emergency cases an 'acute' SPECT can be performed in illnesses with rapid changing symptoms such as different forms of migraine, transient global amnesia, epileptic seizures (so-called 'ictal SPECT') or urgent forms like trauma. 3. In cooperation with several departments brain SPECT can be practised as an interventional procedure in clinical and in scientific studies. (orig./MG)

  12. Thin film composite nanofiltration membranes fabricated from quaternized poly(ether ether ketone) with crosslinkable moiety using a benign solvent.

    Science.gov (United States)

    Dong, Xue; Zhang, Qifeng; Zhang, Suobo; Li, Shenghai

    2016-02-01

    Thin film composite nanofiltration membranes were fabricated through dip-coating and in situ cross-linking of quaternized poly(ether ether ketone) containing a certain amount of tertiary amine groups (QAPEEKs) on polyacrylonitrile (PAN) support. The effects of the variables in membrane formation such as the coating polymer concentration, the curing temperature, and the cross-linking agent types on resultant membrane were studied and the membrane properties such as the barrier layer chemical structure, the surface element composition and morphology were investigated. The obtained performance of uncross-linked and cross-linked QAPEEK-70 thin film composites in nanofiltration test was compared. The results indicated that the cross-linking improved the composite membranes' performance. For instance, the membrane cross-linked by bisphenol A diglycidyl ether (BPADGE) named M-C-BPADGE exhibited a MgCl2 rejection of 97.8%, a water flux of 11.8Lm(-2)h(-1), a MWCO of 800Da and corresponding pore size of 0.69nm, while for its uncross-linked membrane named M-U, a MgCl2 rejection of 91.2%, a water flux of 13.5Lm(-2)h(-1), a MWCO with 960Da and a pore size of 0.77nm were found. Furthermore, the M-C-BPADGE membrane exhibited selectivities of 16.0 for separation of mixed Mg(2+) and Na(+) cations, much larger than selectivity of 5.2 obtained for M-U, suggesting that the cross-linked membranes are promising in cation separation. PMID:26606594

  13. Organic brain syndrome

    Science.gov (United States)

    OBS; Organic mental disorder (OMS); Chronic organic brain syndrome ... Listed below are disorders associated with OBS. Brain injury caused by ... the brain ( subarachnoid hemorrhage ) Blood clot inside the ...

  14. 1,6-Bis(4-vinylphenyl)hexane as a crosslinking agent for the preparation of crosslinked sulfonated poly(ether ether ketone) membranes by EB irradiation

    International Nuclear Information System (INIS)

    In order to mitigate problems associated with highly sulfonated aromatic hydrocarbon membranes, such as dimensional stability, mechanical strength, and methanol crossover, sulfonated poly(ether ether ketone) (SPEEK) membranes containing 1,6-bis(4-vinylphenyl)hexane (BVPH) were crosslinked by EB irradiation. Compared to the pristine SPEEK membrane, the crosslinked membranes exhibited significantly improved dimensional stability, chemical stability, and mechanical strength. The crosslinking procedure slightly reduced the proton conductivity of the membranes. The crosslinking of SPEEK with BVPH was also found to slightly reduce the proton conductivity of the membranes, but significantly reduced the methanol permeability. - Highlights: • 1,6-Bis(4-vinylphenyl)hexane (BVPH) was prepared as a crosslinking agent. • Sulfonated poly(ether ether ketone) was crosslinked using BVPH via EB irradiation. • The crosslinked membranes showed greatly improved dimensional and chemical stability. • The crosslinking process only slightly decreased the proton conductivity. • The crosslinked membranes exhibited substantially reduced methanol permeability

  15. A convenient procedure for the synthesis of allyl and benzyl ethers from alcohols and phenols

    Indian Academy of Sciences (India)

    H Surya Prakash Rao; S P Senthilkumar

    2001-06-01

    Allyl and benzyl ethers of alcohols can be prepared conveniently and in high yield with allyl and benzyl bromide in the presence of solid potassium hydroxide without use of any solvent. Phenols can be converted to allyl ethers but are inert to benzylation under above conditions.

  16. AN EVALUATION OF THE HUMAN CARCINOGENIC POTENTIAL OF ETHYLENE GLYCOL BUTYL ETHER: INTERIM FINAL POSITION PAPER

    Science.gov (United States)

    In order to determine the merit of a petition to remove ethylene glycol ether (EGBE) from the Agency's Hazardous Air Pollutant (HAP) list, EPA has developed an interim final position paper, An Evaluation of the Human Carcinogenic Potential of Ethylene Glycol Butyl Ether, t...

  17. 75 FR 4288 - Oxirane, 2-Methyl-, Polymer with Oxirane, Dimethyl Ether; Tolerance Exemption

    Science.gov (United States)

    2010-01-27

    ... oxirane, dimethyl ether (CAS Reg. No. 61419-46-3); minimum number average molecular weight (in AMW) 2,800.... * * * * * * * Oxirane, 2-methyl-, polymer with 61419-46-3 oxirane, dimethyl ether, minimum number average molecular... under docket identification (ID) number EPA-HQ-OPP-2009-0675. All documents in the docket are listed...

  18. Reaction Pathways and Energetics of Etheric C–O Bond Cleavage Catalyzed by Lanthanide Triflates

    Energy Technology Data Exchange (ETDEWEB)

    Assary, Rajeev S.; Atesin, Abdurrahman C.; Li, Zhi; Curtiss, Larry A.; Marks, Tobin J.

    2013-09-06

    Efficient and selective cleavage of etheric C-O bonds is crucial for converting biomass into platform chemicals and liquid transportation fuels. In this contribution, computational methods at the DFT B3LYP level of theory are employed to understand the efficacy of lanthanide triflate catalysts (Ln(OTf)3, Ln = La, Ce, Sm, Gd, Yb, and Lu) in cleaving etheric C-O bonds. In agreement with experiment, the calculations indicate that the reaction pathway for C-O cleavage occurs via a C-H → O-H proton transfer in concert with weakening of the C-O bond of the coordinated ether substrate to ultimately yield a coordinated alkenol. The activation energy for this process falls as the lanthanide ionic radius decreases, reflecting enhanced metal ion electrophilicity. Details of the reaction mechanism for Yb(OTf)3-catalyzed ring opening are explored in depth, and for 1-methyl-d3-butyl phenyl ether, the computed primary kinetic isotope effect of 2.4 is in excellent agreement with experiment (2.7), confirming that etheric ring-opening pathway involves proton transfer from the methyl group alpha to the etheric oxygen atom, which is activated by the electrophilic lanthanide ion. Calculations of the catalytic pathway using eight different ether substrates indicate that the more rapid cleavage of acyclic versus cyclic ethers is largely due to entropic effects, with the former C-O bond scission processes increasing the degrees of freedom/particles as the transition state is approached.

  19. Aspects of reaction of N-oxide radical with ethers in 13C NMR spectrum

    International Nuclear Information System (INIS)

    The stable radical N-oxide 2,2,6,6-tetramethylpiperidine was dissolved in ethers. The 13C NMR spectra were recorded in the temperature 313K at the frequency 22,625 MHz on the spectrometers with Fourier transformation. The dissolution of the radical in ether caused the contact shifts in NMR spectra. The shifts were measured. (A.S.)

  20. SOLUTION EFFECTS ON CESIUM COMPLEXATION WITH CALIXARENE CROWN ETHERS FROM LIQUID TO SUPERCRITICAL FLUIDS

    Science.gov (United States)

    Calixarene-crown ethers with rigid skeletons are superior to flexible crown ethers for separation of 137Cs from high level waste (HLW). However, this extraction methodology often requires undesirable solvents and the extraction efficiency is strongly dependent on the solvent pol...

  1. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide...

  2. Radiation-induced cationic polymerization of vinyl ethers in solution

    International Nuclear Information System (INIS)

    The influences of the polymerization media, the monomer and solvent concentrations and the temperature on the radiation-induced polymerization of isopropyl vinyl ether (IPVE) have been studied in detail under super-dry conditions. Rates of polymerization were measured and estimates of the rate constants of polymerization were calculated according to the simplified Hayashi-Williams equation. A comparison of the results with those previously reported for ethyl vinyl ether (EVE) is made. The much higher reactivity of IPVC in low polar solvents is interpreted by a drastic reduction of the polymer intramolecular solvation of the growing chain ends. This is ascribed to the bulkiness of the isopropyl side-chain groups. The radiation-induced polymerization of IPVE in bulk and in various solvents with different physical and solvating properties was studied. This was to obtain further information on the kinetics and the mechanisms involved with this monomer and also the role of the polymerization media. The influence of the monomer and solvent concentrations and of the polymerization temperature on the rate of polymerization have also been investigated. (author)

  3. A model survey meter using undoped poly (ether sulfone)

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hidehito, E-mail: hidehito@rri.kyoto-u.ac.jp [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shirakawa, Yoshiyuki [National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kanayama, Masaya; Sato, Nobuhiro [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Kitamura, Hisashi [National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Takahashi, Sentaro [Kyoto University, 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

    2015-04-21

    The large region surrounding the damaged Fukushima Daiichi Nuclear Power Plant has necessitated the use of numerous radiation survey meters with large, robust substrates. The survey meters require efficient scintillation materials that do not require doping and have dimensional stability, such as poly (ether sulfone) (PES) resins. Here, we demonstrate the performance of a model survey meter that uses large PES plates with polished, mirrored surfaces and rough, scattering surfaces. Light collection efficiencies from plates having one or more of these surfaces were quantitatively Characterised with {sup 36}Cl-, {sup 60}Co-, {sup 137}Cs-radioactive sources. The count rates of plates having a combination of mirrored/scattering-surfaces are >1.6 times that for plates having two mirrored surfaces. In addition, a significant amount of radiation-induced light generated in the PES is trapped inside the plate because of its relatively high refractive index. The results indicate that large, undoped PES plates can be used in radiation survey meters. - highlights: • Undoped poly (ether sulfone) (PES) can be used as a scintillation material in radiation survey meters. • Large PES plates with treated surfaces were characterized. • Surface roughening of the plates increased light collection efficiency. • Plates with a combination of mirrored/scattering surfaces work best. • A significant amount of light generated by radiation remains in the PES plates.

  4. Novel Ordered Crown Ether-Containing Polyimides for Ion Conduction

    Science.gov (United States)

    Irvin, Jennifer A.; Stasko, Daniel; Fallis, Stephen; Guenthner, Andrew J.; Webber, Cynthia; Blackwell, John; Chvalun, Sergei N.

    2003-01-01

    We report the synthesis and characterization of thermally-stable polyimides for use as battery and fuel cell electrolyte membranes. Dianhydrides used were 1,4,5,8- naphthalenetetracarboxylic dianhydride and/or 4,4'-(hexafluoroisopropylidene)diphthalic anhydride. Diamines used were anti-4,4-diaminodibenzo-l8-crown-6, 4,4'- diaminodibenzo-24-crown-8, 2,2-bis(4-aminophenyl)hexafluoropropane, and/or 2,5- diaminobenzenesulfonic acid. The polymers were characterized using electrochemical impedance spectroscopy (EIS), thermal analysis and X-ray diffraction. Polymers containing the hexafluoroisopropylidene (HFIP) group were soluble in common organic solvents, while polymers without the HFIP group were very poorly soluble. Sulfonation yields polymers that are sparingly soluble in aqueous base and/or methanol. Degree of sulfonation, determined by titration, was between one and three sulfonate groups per repeat unit. Proton conductivity was determined as a function of water content, with a maximum conductivity of l x 10(exp -2) per centimeter when fully hydrated. Crown ether-containing polymers exhibit a high degree of order that may be indicative of crown ether channel formation, which may facilitate Li(+) transport for use in battery membranes.

  5. Diphytanyl glycerol ether distributions in sediments of the Orca Basin

    Science.gov (United States)

    Pease, Tamara K.; Van Vleet, Edward S.; Barre, Jill S.

    1992-09-01

    Archaebacterially produced diphytanyl glycerol ether (DPGE) was examined in core sediments from the Orca Basin, an anoxic hypersaline basin in the northwestern Gulf of Mexico, to observe its spatial variability and potential origin. A differential extraction protocol was employed to quantify the isopranyl glycerol ethers associated with unbound, intermediate-bound, and kerogen-bound lipid fractions. Archaebacterial lipids were evident at all depths for the unbound and intermediate-bound fractions. Concentrations of DPGE ranged from 0.51 to 2.91 μg/g dry sediment at the surface and showed secondary maxima deeper in basin sediments. Intermediate-bound DPGE concentrations exhibited an inverse relationship to unbound DPGE concentrations. Kerogen-bound DPGE concentrations were normally below detection limits. Earlier studies describing the general homogeneity of lipid components within the overlying brine and at the brine/seawater interface suggest that the large-scale sedimentary DPGE variations observed in this study result from spatial and temporal variations in in situ production by methanogenic or extremely halophilic archaebacteria.

  6. Crystal structure and thermal property of polyethylene glycol octadecyl ether

    International Nuclear Information System (INIS)

    Highlights: ► The crystal structure of C18En for n ≥ 20 is a monoclinic system. ► Polyethylene glycol octadecyl ether crystallizes perfectly. ► The number of repeat units has significant effect on the melting, crystallizing temperature and enthalpy. ► The thermal stable temperature increases rapidly with increasing the number of repeat unit. - Abstract: The crystal structure, phase change property and thermal stable temperature (Td) of polyethylene glycol octadecyl ether [HO(CH2CH2O)nC18H37, C18En] with various numbers of repeat units (n = 2, 10, 20 and 100) as phase change materials (PCMs) were investigated using temperature variable Fourier transformed infrared spectroscopy (FTIR), wide-angle X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). C18En crystallizes perfectly at 0 °C; and the crystal structure for n ≥ 20 is a monoclinic system. The number of repeat units has great effect on the phase change properties of C18En. The thermal stable temperature increases rapidly with increasing the number of repeat units. They approach to that of PEG-2000 as the number of repeat units is more than 10. Td increases rapidly with increasing the number of repeat units. C18En are a series of promising polymeric PCMs

  7. Sorption-desorption behavior of polybrominated diphenyl ethers in soils

    International Nuclear Information System (INIS)

    Polybrominated diphenyl ethers (PBDEs) are flame retardants that are commonly found in commercial and household products. These compounds are considered persistent organic pollutants. In this study, we used 4,4'-dibromodiphenyl ether (BDE-15) as a model compound to elucidate the sorption and desorption behavior of PBDEs in soils. The organic carbon-normalized sorption coefficient (KOC) of BDE-15 was more than three times higher for humin than for bulk soils. However, pronounced desorption hysteresis was obtained mainly for bulk soils. For humin, increasing concentration of sorbed BDE-15 resulted in decreased desorption. Our data illustrate that BDE-15 and probably other PBDEs exhibit high sorption affinity to soils. Moreover, sorption is irreversible and thus PBDEs can potentially accumulate in the topsoil layer. We also suggest that although humin is probably a major sorbent for PBDEs in soils, other humic materials are also responsible for their sequestration. - Highlights: → BDE-15 exhibited pronounced desorption hysteresis. → BDE-15 sowed higher sorption affinity to humin as compared to the bulk soils. → Sequestration of PBDEs depends on soil organic matter constitutes other than humin. - Pronounced desorption hysteresis was observed for BDE-15 in natural soils.

  8. Crystal structure and thermal property of polyethylene glycol octadecyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Jie-yun; Tang, Xiao-fen; Li, Wei; Shi, Hai-feng [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, School of Material Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Zhang, Xing-xiang, E-mail: zhangpolyu@yahoo.com.cn [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, School of Material Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

    2013-04-20

    Highlights: ► The crystal structure of C18En for n ≥ 20 is a monoclinic system. ► Polyethylene glycol octadecyl ether crystallizes perfectly. ► The number of repeat units has significant effect on the melting, crystallizing temperature and enthalpy. ► The thermal stable temperature increases rapidly with increasing the number of repeat unit. - Abstract: The crystal structure, phase change property and thermal stable temperature (T{sub d}) of polyethylene glycol octadecyl ether [HO(CH{sub 2}CH{sub 2}O){sub n}C{sub 18}H{sub 37}, C18En] with various numbers of repeat units (n = 2, 10, 20 and 100) as phase change materials (PCMs) were investigated using temperature variable Fourier transformed infrared spectroscopy (FTIR), wide-angle X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). C18En crystallizes perfectly at 0 °C; and the crystal structure for n ≥ 20 is a monoclinic system. The number of repeat units has great effect on the phase change properties of C18En. The thermal stable temperature increases rapidly with increasing the number of repeat units. They approach to that of PEG-2000 as the number of repeat units is more than 10. T{sub d} increases rapidly with increasing the number of repeat units. C18En are a series of promising polymeric PCMs.

  9. Developmental toxicity of diphenyl ether herbicides in nestling American kestrels.

    Science.gov (United States)

    Hoffman, D J; Spann, J W; LeCaptain, L J; Bunck, C M; Rattner, B A

    1991-11-01

    Beginning the day after hatching, American kestrel (Falco sparverius) nestlings were orally dosed for 10 consecutive days with 5 microliters/g of corn oil (controls) or one of the diphenyl ether herbicides (nitrofen, bifenox, or oxyfluorfen) at concentrations of 10, 50, 250, or 500 mg/kg in corn oil. At 500 mg/kg, nitrofen resulted in complete nestling mortality, bifenox in high (66%) mortality, and oxyfluorfen in no mortality. Nitrofen at 250 mg/kg reduced nestling growth as reflected by decreased body weight, crown-rump length, and bone lengths including humerus, radius-ulna, femur, and tibiotarsus. Bifenox at 250 mg/kg had less effect on growth than nitrofen, but crown-rump, humerus, radius-ulna, and femur were significantly shorter than controls. Liver weight as a percent of body weight increased with 50 and 250 mg/kg nitrofen. Other manifestations of impending hepatotoxicity following nitrofen ingestion included increased hepatic GSH peroxidase activity in all nitrofen-treated groups, and increased plasma enzyme activities for ALT, AST, and LDH-L in the 250-mg/kg group. Bifenox ingestion resulted in increased hepatic GSH peroxidase activity in the 50- and 250-mg/kg groups. Nitrofen exposure also resulted in an increase in total plasma thyroxine (T4) concentration. These findings suggest that altricial nestlings are more sensitive to diphenyl ether herbicides than young or adult birds of precocial species. PMID:1942122

  10. A model survey meter using undoped poly (ether sulfone)

    International Nuclear Information System (INIS)

    The large region surrounding the damaged Fukushima Daiichi Nuclear Power Plant has necessitated the use of numerous radiation survey meters with large, robust substrates. The survey meters require efficient scintillation materials that do not require doping and have dimensional stability, such as poly (ether sulfone) (PES) resins. Here, we demonstrate the performance of a model survey meter that uses large PES plates with polished, mirrored surfaces and rough, scattering surfaces. Light collection efficiencies from plates having one or more of these surfaces were quantitatively Characterised with 36Cl-, 60Co-, 137Cs-radioactive sources. The count rates of plates having a combination of mirrored/scattering-surfaces are >1.6 times that for plates having two mirrored surfaces. In addition, a significant amount of radiation-induced light generated in the PES is trapped inside the plate because of its relatively high refractive index. The results indicate that large, undoped PES plates can be used in radiation survey meters. - highlights: • Undoped poly (ether sulfone) (PES) can be used as a scintillation material in radiation survey meters. • Large PES plates with treated surfaces were characterized. • Surface roughening of the plates increased light collection efficiency. • Plates with a combination of mirrored/scattering surfaces work best. • A significant amount of light generated by radiation remains in the PES plates

  11. Sorption-desorption behavior of polybrominated diphenyl ethers in soils

    Energy Technology Data Exchange (ETDEWEB)

    Olshansky, Yaniv; Polubesova, Tamara [Department of Soil and Water Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100 (Israel); Vetter, Walter [Institute of Food Chemistry (170b), University of Hohenheim, Garbenstr. 28, D-70599 Stuttgart (Germany); Chefetz, Benny, E-mail: chefetz@agri.huji.ac.il [Department of Soil and Water Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100 (Israel)

    2011-10-15

    Polybrominated diphenyl ethers (PBDEs) are flame retardants that are commonly found in commercial and household products. These compounds are considered persistent organic pollutants. In this study, we used 4,4'-dibromodiphenyl ether (BDE-15) as a model compound to elucidate the sorption and desorption behavior of PBDEs in soils. The organic carbon-normalized sorption coefficient (K{sub OC}) of BDE-15 was more than three times higher for humin than for bulk soils. However, pronounced desorption hysteresis was obtained mainly for bulk soils. For humin, increasing concentration of sorbed BDE-15 resulted in decreased desorption. Our data illustrate that BDE-15 and probably other PBDEs exhibit high sorption affinity to soils. Moreover, sorption is irreversible and thus PBDEs can potentially accumulate in the topsoil layer. We also suggest that although humin is probably a major sorbent for PBDEs in soils, other humic materials are also responsible for their sequestration. - Highlights: > BDE-15 exhibited pronounced desorption hysteresis. > BDE-15 sowed higher sorption affinity to humin as compared to the bulk soils. > Sequestration of PBDEs depends on soil organic matter constitutes other than humin. - Pronounced desorption hysteresis was observed for BDE-15 in natural soils.

  12. Developmental toxicity of diphenyl ether herbicides in nestling American kestrels

    Science.gov (United States)

    Hoffman, D.J.; Spann, J.W.; LeCaptain, L.J.; Bunck, C.M.; Rattner, B.A.

    1991-01-01

    Beginning the day after hatching, American kestrel (Falco sparverius) nestlings were orally dosed for 10 consecutive days with 5 microliters/g of corn oil (controls) or one of the diphenyl ether herbicides (nitrofen, bifenox, or oxyfluorfen) at concentrations of 10, 50, 250, or 500 mg/kg in corn oil. At 500 mg/kg, nitrofen resulted in complete nestling mortality, bifenox in high (66%) mortality, and oxyfluorfen in no mortality. Nitrofen at 250 mg/kg reduced nestling growth as reflected by decreased body weight, crownrump length, and bone lengths including humerus, radiusulna, femur, and tibiotarsus. Bifenox at 250 mg/kg had less effect on growth than nitrofen, but crownrump, humerus, radiusulna, and femur were significantly shorter than controls. Liver weight as a percent of body weight increased with 50 and 250 mg/kg nitrofen. Other manifestations of impending hepatotoxicity following nitrofen ingestion included increased hepatic GSH peroxidase activity in all nitrofentreated groups, and increased plasma enzyme activities for ALT, AST, and LDHL in the 250mg/kg group. Bifenox ingestion resulted in increased hepatic GSH peroxidase activity in the 50and 250mg/kg groups. Nitrofen exposure also resulted in an increase in total plasma thyroxine (T4) concentration. These findings suggest that altricial nestlings are more sensitive to diphenyl ether herbicides than young or adult birds of precocial species.

  13. Silica-based nanocomposite membranes via the sol gel process of polyethoxysiloxane within a sulfonated poly(ether-ether-ketone) matrix: morphology and proton mobility

    OpenAIRE

    Colicchio, Irene

    2009-01-01

    This thesis deals with the preparation and characterization of hybrid organic/inorganic membranes obtained from solutions, where the organic phase is the sulfonated poly(ether ether ketone) (SPEEK) and the inorganic phase are silica nanoparticles obtained from the in situ "water free" sol-gel process of polyethoxysiloxane (PEOS). PEOS is a soluble and liquid hyperbranched polymer of low viscosity synthesized in our laboratories via a one pot reaction between tetraethoxysilane (TEOS) and aceti...

  14. Rational Design of Cesium-Selective Ionophores and Chemosensors: Dihydrocalix[4]arene Crown-6 Ethers

    Energy Technology Data Exchange (ETDEWEB)

    Sachleben, Richard A.; Bryan, Jeffrey C.; Brown, Gilbert M.; Engle, Nancy L.; Haverlock, Tamara J.; Hay, Benjamin P.; Urvoas, Agathe; Moyer, Bruce A.

    2003-12-15

    Molecular mechanics calculations performed on calix[4]arene crown-6 ethers predict that the 1,3-dihydro derivatives will exhibit greater complementarity for potassium and cesium ions than the parent 1,3-dialkoxy calix crowns. The X-ray crystal structures of 1,3-alt bis-octyloxycalix[4]arene benzocrown-6 ether, dihydrocalix[4]arene benzocrown-6 ether, and the cesium nitrate complex of dihydrocalix[4]arene benzocrown-6 ether were determined. The cesium complex structure corresponds closely to the structure predicted by molecular mechanics. The dihydrocalix[4]arene crown-6 ethers exhibit enhanced cesium selectivity in the extraction of alkali metal salts and provide a platform for a highly sensitive and selective cesium chemosensor.

  15. Oil recovery with sulfomethylated poly (lower alkyl vinyl ether/maleic anhydride)

    Energy Technology Data Exchange (ETDEWEB)

    Norton, C.J.; Falk, D.O.

    1973-05-22

    Lower alkyl vinyl ether e.g., methyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, hexyl vinyl ether, is copolymerized conventionally with maleic anhydride, the resulting copolymer is treated with ammonia or ammonium hydroxide to form the partial amide-ammonium salt, and this salt is in turn treated with formaldehyde and thereafter or simultaneously with ammonium or alkali metal salt sulfite (including bisulfites, etc.) to form an at least partially sulfomethylated copolymer. Aqueous solutions of the sulfomethylated copolymer are useful in increasing the viscosity of drive fluids used in the supplemented recovery of petroleum from subterranean formations. In general, enhancing the polyionic character of mobility control agents used in supplemented recovery of petroleum provides enhanced recovery. Achieving this enhancement of polyionic character through use of sulfonate groups provides a mobility control agent with good ability to sustain viscosity in the presence of brine and lime, usually present in the connate waters of petroleum-bearing formations. (7 claims)

  16. Phytochemical comparison between Pet ether and ethanolic extracts of Bacopa monnieri, Evolvulus alsinoides and Tinospora cordifolia.

    Science.gov (United States)

    Gupta, Avneet; Raj, Hem; Sharma, Bhartendu; Upmanyu, Neeraj

    2014-04-01

    Bacopa monnieri, Evolvulus alsinoides and Tinospora cordifolia are established ayurvedic herbs having neuropharmacological effect. In present study is aimed to Phytochemical Comparison between Pet ether and Ethanolic extracts of Bacopa monnieri (BME), Evolvulus alsinoides (EAE) and Tinospora cordifolia (TCE). To identify the presence (+) or absence (-) of different phytoconstituents in Pet ether and Ethanolic extracts of BME, EAE and TCE by using various phytochemical testing methods. Phytochemical investigation showed the presence of various phytochemical constituents in Pet ether and Ethanolic extracts of BME, EAE and TCE. When comparison between Pet ether and Ethanolic extracts of BME, EAE and TCE; Ethanolic extracts of these plants showed more phytoconstituents as compared to Pet ether extracts of these plants. From present investigation, it can be concluded that phytochemical comparison is subsequently momentous and useful in finding chemical constituents in the plant substances that may lead to their quantitative evaluation and also pharmacologically active chemical compounds. PMID:25911854

  17. Interaction of water with different cellulose ethers: a Raman spectroscopy and environmental scanning electron microscopy study.

    Science.gov (United States)

    Fechner, P M; Wartewig, S; Kiesow, A; Heilmann, A; Kleinebudde, P; Neubert, R H H

    2005-06-01

    Different non-ionic cellulose ethers like methyl cellulose (MC), hydroxypropyl cellulose (HPC) and hydroxypropylmethyl cellulose (HPMC) were investigated. The characterization of the cellulose ethers was carried out by thermogravimetry and sorption/desorption isotherms. Differences in the properties of the cellulose ether films were described by time-dependent contact angle measurements. Changes in molecular structure of the raw materials, gels and films caused by water contact were studied using Raman spectroscopy. Differences between the substitution types and changes due to the gel or film formation were observed. An environmental scanning electron microscopy (ESEM) technique was used to distinguish the morphological behaviour of the cellulose ether films in contact with water. Based on in-situ ESEM experiments, the swelling and drying behaviour of the various stages of cellulose ether films (film-hydrated film-dried film) were quantified by using image analysis. PMID:15969923

  18. Mutual solubility in the system uranyl trifluoroacetate--water--diethyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Vdovenko, V.M.; Baluev, A.V.; Suglobova, I.G.

    1975-01-01

    A study was made of mutual solubility in the system uranyl trifluoroacetate--water--diethyl ether at 25/sup 0/C. It was found that uranyl trifluoroacetate, like the trichloroacetate which was investigated previously, is extracted by diethyl ether much better than uranyl nitrate over a wide range of concentrations. The solubility of UO/sub 2/(CF/sub 3/COO)/sub 2/ in ether depends strongly on the water content of the system. While the anhydrous salt is practically insoluble, the addition of two H/sub 2/O molecules to a molecule of UO/sub 2/(CF/sub 3/COO)/sub 2/ leads to an increase in solubility to approximately 75 wt. percent. On the basis of the ir spectra of ether solutions of uranyl trifluoroacetate in the presence of semiheavy water (HDO) it was established that the hydration envelope of the complex in diethyl ether has a layer structure.

  19. Metal ion complexation by ionizable crown ethers. Progress report, January 1, 1991--December 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, R.A.

    1993-07-01

    Cyclic and acyclic polyether compounds with pendent carboxylic acid, phosphonic acid monoethyl ester, sulfonic acid, phosphinic acid and hydroxamic acid groups have been synthesized. The proton-ionizable polyethers can come with and without lipophilic groups. Two types of lipophilic di-ionizable lariat ethers have been prepared. Conformations of proton-ionizable lariat ethers have been probed. Competitive alkali metal cation transport by syn-(decyl)dibenzo-16-crown-5-oxyacetic acid and lipophilic proton-ionizable dibenzo lariat ethers in polymer-supported liquid membranes was studied. Complexation of alkali metal cations with ionized lariat ethers was studied. Condensation polymerization of cyclic and acyclic dibenzo polyethers containing pendent mono-ionizable groups with formaldehyde produces novel ion exchange resins with both ion exchange sites for metal ion complexation and polyether binding sites for metal ion recognition. Resins prepared from lariat ether dibenzo phosphonic acid monoethyl esters show strong sorption of divalent heavy metal cations with selectivity for Pb{sup 2+}.

  20. Halogen derivatives of benzo- and dibenzocrown ethers: synthesis, structure, properties and application

    Science.gov (United States)

    Pluzhnik-Gladyr, S. M.

    2016-02-01

    Methods of synthesis of halogenated benzo- and dibenzocrown ether derivatives are surveyed: halogenation of benzo- and dibenzocrown ethers with molecular halogens, N-halosuccinimides in the solid phase and different media (water, ethanol, halohydrocarbons) and hypohalites in water, as well as the 'assembly' method. Reactions of these compounds are considered: synthesis of phosphorus-containing crown ethers, organometallic synthesis, the Heck and Sonogashira reactions, synthesis of acetylene derivatives and other reactions. Special attention is focused on the complexing properties of halogenated benzocrown ethers with respect to ionic guests and neutral organic molecules. The possibility of synthesis of complexes of such compounds in the solid phase is demonstrated. The extraction and sorption properties of halogenated benzo- and dibenzocrown ethers are considered. Examples of practical use of these compounds are presented. The bibliography includes 203 references.

  1. A method of communication between EPICS IOC and EtherCAT devices%EPICS IOC与EtherCAT设备通信的一种方法

    Institute of Scientific and Technical Information of China (English)

    何泳成; 王春红; 吴煊

    2014-01-01

    EtherCAT (Ethemet Control Automation Technology)是一种用于工业自动化的实时以太网现场总线协议.通过使用OPC (Object Linking and Embedding for Process Control) Gateway驱动程序实现了EPICS(Experimental Physics and Industrial Control System) IOC (Input/Output Controller)与EtherCAT设备的通信,从而使EtherCAT成为加速器控制系统中对实时性要求很高的高速控制系统的一种解决方案.在简要介绍EPICS、EtherCAT、OPC及OPC Gateway的基础上,对使用OPC Gateway驱动程序实现EPICS IOC与EtherCAT设备通信进行了测试.结果表明,EPICS IOC可通过OPC Gateway驱动程序与EtherCAT设备正常通信.

  2. Brain Basics

    Medline Plus

    Full Text Available ... Amygdala —The brain's "fear hub," which activates our natural "fight-or-flight" response to confront or escape ... husband questions about Sarah's symptoms and family medical history. Epigenetic changes from stress or early-life experiences ...

  3. Brain Basics

    Medline Plus

    Full Text Available ... managing proper emotional reactions. Reduced ACC activity or damage to this brain area has been linked to ... can diagnose mental disorders are psychologists or clinical social ... —A network of neurons and their interconnections. neuron —A nerve ...

  4. Brain Basics

    Medline Plus

    Full Text Available ... how to slow or stop them from progressing. Functional magnetic resonance imaging (fMRI) is another important research ... magnetic fields to take pictures of the brain's structure. mutation —A change in the code for a ...

  5. Brain Basics

    Medline Plus

    Full Text Available ... or post-traumatic stress disorder (PTSD) . Prefrontal cortex (PFC) —Seat of the brain's executive functions, such as ... making, and problem solving. Different parts of the PFC are involved in using short-term or "working" ...

  6. Brain Basics

    Medline Plus

    Full Text Available ... at the front of the brain that, in humans, plays a role in executive functions such as ... ClinicalTrials.gov : Federally and privately supported research using human volunteers PubMed Central: An archive of life sciences ...

  7. Robot brains

    NARCIS (Netherlands)

    Babuska, R.

    2011-01-01

    The brain hosts complex networks of neurons that are responsible for behavior in humans and animals that we generally call intelligent. I is not easy to give an exact definition of intelligence – for the purpose of this talk it will suffice to say that we refer to intelligence as a collection of cap

  8. Brain Basics

    Medline Plus

    Full Text Available ... improve treatments for anxiety disorders like phobias or post-traumatic stress disorder (PTSD) . Prefrontal cortex (PFC) —Seat of the brain's executive ... events. Some research shows that people who have PTSD or ADHD have reduced activity in their PFCs. ...

  9. Brain Basics

    Medline Plus

    Full Text Available ... they can cause tremors or symptoms found in Parkinson's disease. Serotonin —helps control many functions, such as mood, ... brain. Problems in producing dopamine can result in Parkinson's disease, a disorder that affects a person's ability to ...

  10. Brain Basics

    Medline Plus

    Full Text Available ... occur when this process does not work correctly. Communication between neurons can also be electrical, such as in areas of the brain that control movement. When electrical signals are abnormal, they can cause tremors or symptoms found in Parkinson's disease. Serotonin — ...

  11. Brain Basics

    Medline Plus

    Full Text Available ... brain disorders. Evidence shows that they can be related to changes in the anatomy, physiology, and chemistry ... MEDLINEPlus : Authoritative information from government agencies and health-related organizations, available in both English and Spanish ( Español ) ...

  12. Brain Basics

    Medline Plus

    Full Text Available ... unit of the brain and nervous system, which processes and transmits information. neurotransmitter —A chemical produced by ... decision making and problem solving, as well as emotional control and memory. serotonin —A neurotransmitter that regulates ...

  13. Brain Basics

    Medline Plus

    Full Text Available ... early brain development. It may also assist in learning and memory. Problems in making or using glutamate have been linked ... we see, and help us to solve a problem. Some of the regions most commonly ... also appears to be involved in learning to fear an event, such as touching a ...

  14. Brain Basics

    Medline Plus

    Full Text Available ... ADHD , schizophrenia , and depression . Hippocampus —Helps create and file new memories. When the hippocampus is damaged, a ... portion of the brain involved in creating and filing new memories. hypothalmic-pituitary-adrenal (HPA) axis —A ...

  15. Polybrominated Diphenyl Ethers Alter Hepatic Phosphoenolpyruvate Carboxykinase Enzyme Kinetics in Male Wistar Rats: Implications for Lipid and Glucose Metabolism

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDE) are a family of lipophilic brominated flame-retardants consisting of 209 possible congeners. Three PBDE commercially-produced mixtures are decabrominated diphenyl ether (e.g. deca-BDE or DE-83R); octabrominated diphenyl ether (e.g. octa-BDE o...

  16. 40 CFR 721.6980 - Dimer acids, polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and alky-lenepolyols...

    Science.gov (United States)

    2010-07-01

    ... glycol, bisphenol A-diglycidyl ether, and alky-lenepolyols polyglycidyl ethers (generic name). 721.6980... Substances § 721.6980 Dimer acids, polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and alky... reporting. (1) The chemical substance dimer acids, polymer with polyalkylene glycol, bisphenol...

  17. Biosynthesis of ether-phospholipids including plasmalogens, peroxisomes and human disease: new insights into an old problem

    NARCIS (Netherlands)

    R.J.A. Wanders; P. Brites

    2010-01-01

    Ether-phospholipids represent an important subclass of phospholipids in animal cell membranes characterized by the presence of an ether bond at the sn-I position and the enrichment of PUFAs at the sn-2 position. Of the different ether-phospholipids, plasmalogens are the most abundant form and their

  18. Brain Tumors (For Parents)

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy Brain Tumors KidsHealth > For Parents > Brain Tumors Print A ... radiation therapy or chemotherapy, or both. Types of Brain Tumors There are many different types of brain ...

  19. Brain tumor - children

    Science.gov (United States)

    ... children; Neuroglioma - children; Oligodendroglioma - children; Meningioma - children; Cancer - brain tumor (children) ... The cause of primary brain tumors is unknown. Primary brain tumors may ... (spread to nearby areas) Cancerous (malignant) Brain tumors ...

  20. Unruptured Brain Aneurysms

    Science.gov (United States)

    ... Brain Aneurysm Statistics and Facts Seeking Medical Attention Pediatric Aneurysms Brain Aneurysm Causes and Risk Factors Family History ... Brain Aneurysm Statistics and Facts Seeking Medical Attention Pediatric Aneurysms Brain Aneurysm Causes and Risk Factors Family History ...

  1. Brain Aneurysm: Treatment Options

    Science.gov (United States)

    ... Brain Aneurysm Statistics and Facts Seeking Medical Attention Pediatric Aneurysms Brain Aneurysm Causes and Risk Factors Family History ... Brain Aneurysm Statistics and Facts Seeking Medical Attention Pediatric Aneurysms Brain Aneurysm Causes and Risk Factors Family History ...

  2. Environment effects on the optical properties of some fluorinated poly(oxadiazole ether)s in binary solvent mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Homocianu, Mihaela, E-mail: michalupu@yahoo.co.uk; Ipate, Alina Mirela; Hamciuc, Corneliu; Airinei, Anton

    2015-01-15

    The solvatochromic behavior of some fluorinated poly(oxadiazole ether)s was studied using UV–vis absorption and fluorescence spectroscopy in neat solvents and in their solvent mixtures at several ratios of cosolvents. Quantitative investigations of the spectral changes caused by solvent polarity were discussed using the Lippert‐Mataga, Bakhshiev and Kawski–Chamma–Viallet polarity functions. Repartitioning of cosolvent between local (solvation shell) and bulk phase was investigated by means of a solvatochromic shift method in chloroform–N,N-dimethylformamide (CHCl{sub 3}/DMF) and chloroform–dimethyl sulfoxide (CHCl{sub 3}/DMSO) solvent mixtures. Solvatochromic properties in the binary solvent environments were predominantly influenced by the acidity and basicity of the solvent systems. The fluorescence quenching process by nitrobenzene was characterized by Stern–Volmer plots which display a positive deviation from linearity. This was explained by static and dynamic quenching mechanisms. - Highlights: • Solvatochromic behavior in solvent mixtures was studied. • Stokes shift and local environments in binary mixed solvent were discussed. • Repartitioning of cosolvent between local and bulk phase in solvent mixture has been investigated. • Fluorescence intensity was quenched in presence of nitrobenzene.

  3. Novel sulfonated poly (ether ether keton)/polyetherimide acid-base blend membranes for vanadium redox flow battery applications

    International Nuclear Information System (INIS)

    Highlights: • SPEEK/PEI acid-base blend membranes are prepared for VRB applications. • The acid-base blend membranes have much lower vanadium ion permeability. • The energy efficiency of SPEEK/PEI maintain around 86.9% after 50 cycles. - Abstract: Novel acid-base blend membranes composed of sulfonated poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared for vanadium redox flow battery (VRB). The blend membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electronic microscopy (SEM). The ion exchange capacity (IEC), proton conductivity, water uptake, vanadium ion permeability and mechanical properties were measured. As a result, the acid-base blend membranes exhibit higher water uptake, IEC and lower vanadium ion permeability compared to Nafion117 membranes and all these properties decrease with the increase of PEI. In VRB single cell test, the VRB with blend membranes shows lower charge capacity loss, higher coulombic efficiency (CE) and energy efficiency (EE) than Nafion117 membrane. Furthermore, the acid-base blend membranes present stable performance up to 50 cycles with no significant decline in CE and EE. All experimental results indicate that the SPEEK/PEI (S/P) acid-base blend membranes show promising prospects for VRB

  4. Computational Approach to Diarylprolinol-Silyl Ethers in Aminocatalysis.

    Science.gov (United States)

    Halskov, Kim Søholm; Donslund, Bjarke S; Paz, Bruno Matos; Jørgensen, Karl Anker

    2016-05-17

    Asymmetric organocatalysis has witnessed a remarkable development since its "re-birth" in the beginning of the millenium. In this rapidly growing field, computational investigations have proven to be an important contribution for the elucidation of mechanisms and rationalizations of the stereochemical outcomes of many of the reaction concepts developed. The improved understanding of mechanistic details has facilitated the further advancement of the field. The diarylprolinol-silyl ethers have since their introduction been one of the most applied catalysts in asymmetric aminocatalysis due to their robustness and generality. Although aminocatalytic methods at first glance appear to follow relatively simple mechanistic principles, more comprehensive computational studies have shown that this notion in some cases is deceiving and that more complex pathways might be operating. In this Account, the application of density functional theory (DFT) and other computational methods on systems catalyzed by the diarylprolinol-silyl ethers is described. It will be illustrated how computational investigations have shed light on the structure and reactivity of important intermediates in aminocatalysis, such as enamines and iminium ions formed from aldehydes and α,β-unsaturated aldehydes, respectively. Enamine and iminium ion catalysis can be classified as HOMO-raising and LUMO-lowering activation modes. In these systems, the exclusive reactivity through one of the possible intermediates is often a requisite for achieving high stereoselectivity; therefore, the appreciation of subtle energy differences has been vital for the efficient development of new stereoselective reactions. The diarylprolinol-silyl ethers have also allowed for novel activation modes for unsaturated aldehydes, which have opened up avenues for the development of new remote functionalization reactions of poly-unsaturated carbonyl compounds via di-, tri-, and tetraenamine intermediates and vinylogous iminium ions

  5. Synthesis and characterization of ether-linked porphyrins

    Directory of Open Access Journals (Sweden)

    Radchada Buntem

    2009-07-01

    Full Text Available The ether-linked porphyrin dimers in this research work were prepared from coupling reaction between suitableporphyrin precursors and linkers in the presence of potassium carbonate. The structures of all synthesized compounds werecharacterized by spectroscopic methods. The UV/Visible absorption maxima and extinction coefficients did not show any significant difference among these porphyrin dimers. This indicates that the length of the linker did not affect the absorption property of the dimers. However, different metal ions bonding to the porphyrin moiety affect the different absorption maxima of the porphyrin dimers. It was also found that the position of the linker on the phenyl ring of porphyrin does not affect the visible absorption pattern or the proton chemical shifts of the porphyrin core as found in the case of Zn2(metaC-dimer (13(compared with the data obtained for Zn2C2-dimer (3.

  6. Calorimetric study of binding of some disaccharides with crown ethers

    International Nuclear Information System (INIS)

    Isothermal titration calorimetry has been applied to the determination of the thermodynamic parameters of binding of β-lactose, α,α-trehalose and sucrose with 15-crown-5 and 18-crown-6 in water at 298.15 K. The formation of 1:1 molecular associates has been found for the systems studied except 18-crown-6 and β-lactose. The associates are preferentially or completely entropy stabilized. The most stable associate is formed between α,α-trehalose and 18-crown-6. The obtained values of thermodynamic parameters of binding are discussed from the point of view of solute-solvent interactions as well as conformational and structural peculiarities of the disaccharides (DS) and crown ethers (CE)

  7. Determination of radiostrontium in soil samples using a crown ether

    International Nuclear Information System (INIS)

    A simple and rapid method has been developed for the separation and successive determination of total radiostrontium in soil. The method consists of three basic steps: oxalate precipitation to remove bulk potassium, chromatographic separation of strontium from most inactive and radioactive interferences utilizing a crown ether (Sr. Spec, EIChroM Industries, II. USA), oxalate precipitation of strontium to evaluate the chemical yield. Radiostrontium is then determined by liquid scintillation counting of the dissolved precipitate. When 10 g samples of soil are used the sensitivity of the method is about 10 Bq/kg. The chemical yield is about 80%. The separation and determination of radiostrontium can be carried out in about 8 hours. (author)

  8. Synthesis of Bioactive Natural Polymethoxyflavones and Their Vinyl Ether Derivatives

    Institute of Scientific and Technical Information of China (English)

    CAI Shuang-lian; LIU Shuang; LIU Li; WANG Qiu-an

    2012-01-01

    Bioactive natural polymethoxyflavones 1-6 and their vinyl ether derivatives 7-15 were synthesized by bromination,aromatic nucleophilic substitution,methylation,benzyl protection,Friedel-Crafts acetylation,aldol condensation,cyclization,DDQ dehydrogenation,regioselective demethylation,debenzylation and O-prenylation or O-farnesylation with resorcinol and appropriate substituted benzaldehydes as starting materials.Among them,compounds 7-15 are new compounds.Natural products 2-4 were firstly total synthesized.The syntheses of compounds 1,5 and 6 were efficiently improved by the new synthetic routes.The structures of all synthetic compounds were confirmed by NMR,IR spectra and MS.

  9. Cosmic Background Radiation and `ether-drift' experiments

    CERN Document Server

    Consoli, M; Rapisarda, A

    2016-01-01

    `Ether-drift' experiments have played a crucial role for the origin of relativity. Though, a recent re-analysis shows that those original measurements where light was still propagating in gaseous systems, differently from the modern experiments in vacuum and in solid dielectrics, indicate a small universal anisotropy which is naturally interpreted in terms of a non-local thermal gradient. We argue that this could possibly be the effect, on weakly bound gaseous matter, of the temperature gradient due to the Earth's motion within the Cosmic Background Radiation (CBR). Therefore, a check with modern laser interferometers is needed to reproduce the conditions of those early measurements with today's much greater accuracy. We emphasize that an unambiguous confirmation of our interpretation would have far reaching consequences. For instance, it would also imply that all physical systems on the moving Earth are exposed to a tiny energy flow, an effect that, in principle, could induce forms of self-organization in ma...

  10. An Explanation of Dayton Miller's Anomalous "Ether Drift" Result

    CERN Document Server

    Roberts, T J

    2006-01-01

    In 1933 Dayton Miller published in this journal the results of his voluminous observations using his ether drift interferometer, and proclaimed that he had determined the "absolute motion of the earth". This result is in direct conflict with the prediction of Special Relativity, and also with numerous related experiments that found no such signal or "absolute motion". This paper presents a complete explanation for his anomalous result by: a) showing that his results are not statistically significant, b) describing in detail how flaws in his analysis procedure produced a false signal with precisely the properties he expected, and c) presenting a quantitative model of his systematic drift that shows there is no real signal in his data. In short, this is every experimenter's nightmare: he was unknowingly looking at statistically insignificant patterns in his systematic drift that mimicked the appearance of a real signal. An upper limit on "absolute motion" of 6 km/sec is derived from his raw data, fully consiste...

  11. Chain-extended poly(aryl ether ketones)

    Energy Technology Data Exchange (ETDEWEB)

    Robeson, L.M.; Winslow, P.A.; Matzner, M.; Harris, J.E.; Maresca, L.M.

    1992-06-09

    This patent describes a process for preparing a poly(aryl ether ketone) polymer. It comprises reacting (n) moles of HAr H with (n + 1) moles of YCOAr{sub 1}COY under Friedel-Crafts polymerization conditions; reacting the product obtained with 2XAR{sub 2}H under Friedel-Crafts polymerization conditions; reacting the product obtained with HOAr{sub 3}OH in the presence of a base and an aprotic solvent; wherein Ar and Ar{sub 1} are divalent aromatic groups, Ar{sub 2} is a divalent aromatic group wherein the substituents X and CO are in para or ortho position relative to each other, Ar{sub 3} is a residue of a dihydric phenol, X and Y are halogen, n is an integer of 1 to 50 and X is one or greater.

  12. New controllable premixed combustion for dimethyl ether engine

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new concept of the controllable premixed combustion (CPC) system was proposed for dimethyl ether (DME) to explore a new approach to achieving ultra-low NOX emissions with the zero level of particulate matter exhaust emissions. The DME fuel was injected into the premix chamber by means of the electronically controlled low pressure injection system, then the mixture formation and combustion process were controlled with a control-valve set between the main chamber and the premix chamber. The test bench was constructed based on a single diesel engine. Preliminary studies demonstrated that ultra-low NOX emissions had been realized with zero particulate matter emissions under the optimum specifications of the DME engine, NOX emissions were less than 65 × 10-6. According to the engine combustion analysis, it was found that the control-valve played an important role in the pre-mixture formation and ignition timing.

  13. Hydrogen Production with Steam Reforming of Dimethyl Ether

    Institute of Scientific and Technical Information of China (English)

    Kaoru TAKEISHI; Akane ARASE

    2005-01-01

    @@ 1Introduction Steam reforming of methanol and gasoline is actively researched and developed as hydrogen supply methods for the fuel cells of vehicles and so on. However, these materials have the problems such as the infrastructure, toxicity, difficulty of the reforming, and so forth. Dimethyl ether (DME) does not contain the poisonous substances, and is expected as a clean fuel of the next generation. DME is able to take the place of light oil and LPG, and its physical properties are similar to those of LPG. There is possibility that DME infrastructures will be settled more rapidly than those of hydrogen and methanol, because LPG infrastructures existing are able to use for DME. Then, we have been studying on steam reforming of DME for the hydrogen production.

  14. Degradation of β-Aryl Ether Bonds in Transgenic Plants

    DEFF Research Database (Denmark)

    Mnich, Ewelina

    cell wall. The aim of the study was to alter lignin structure by expression in plants of the enzymes from S. paucimobilis involved in ether bond degradation (LigDFG). Arabidopsis thaliana and Brachypodium distachyon transgenic lines were generated and characterized with respect to lignin structure and......Lignin is one of the main building blocks of the plant cell wall. It tethers the cell wall by cross-linking with polysaccharides conferring mechanical strength to plants, aiding water transport and providing a mechanical barrier against pathogens. It is generated by the polymerization of the....... Compared to other plants grass cell walls contain elevated amount of ferulates which play a crucial role in cross-linking of polysaccharides and lignin. In addition ferulates are believed to be nucleation cites for the lignification. The bacterium Sphingomonas paucimobilis SYK6 has developed an enzyme...

  15. Role of acid catalysis in dimethyl ether conversion processes

    Energy Technology Data Exchange (ETDEWEB)

    Tartamella, T.L.; Lee, S. [Univ. of Akron, OH (United States). Dept. of Chemical Engineering

    1996-12-31

    Acidity plays an important role in the conversion of methanol and dimethyl ether (DME) to hydrocarbons and oxygenates. In the conversion to hydrocarbons over zeolite catalyst, Broensted acidity is the main contributor to the first hydrocarbon formed. Here, acidity is also an important factor in determining olefin, paraffin, and aromatic content in the final product distribution. Catalyst life has also been found to be related to acidity content in zeolites. DME conversion to oxygenates is especially dependent on high acidity catalysts. Superacids like BF{sub 3}, HF-BF{sub 3}, and CF{sub 3}COOH have been used in the past for conversion of DME in carbonylation reactions to form methyl acetate and acetic acid at high pressures. Recently, heteropoly acids and their corresponding metal substituted salts have been used to convert DME to industrially important petrochemicals resulting in shorter reaction times and without the use of harsh operating conditions.

  16. Phytochemical Analysis of Hot Petroleum ether Extracts of Piper nigrum

    Directory of Open Access Journals (Sweden)

    Aditi Gupta

    2013-04-01

    Full Text Available The genus Piper belongs to family piperaceae which has over 700 species distributed in both hemispheres. The piperaceae family is a source of many biologically active photochemical with tremendous potential for medicinal uses. A wide range of secondary metabolites mainly alkaloids, amides and terpenes are reported from the various species of piper which are of great economical and medicinal importance. This paper reports the isolation of various sesqueterpenes such as δ–elemene, δ–cadinene, α–copane, caryophyllene, α–caryophyllene, β–bisabolene, and methyl benzene from the oil of the hot petroleum ether extract of Piper nigrum seeds. These phytochemicals are analysed by GC-MS spectral analysis.

  17. Zinc isotope separation with crown ether by column chromatography

    International Nuclear Information System (INIS)

    Depleted 64Zn is a new useful material and can be widely used in the cooling water treatment in light water nuclear power plants. In the present work, column chromatographic zinc isotope separation was performed by crown ether resin which was synthesized by ourselfs, the experimental results shown that benzo-15-crown-5 resin could effectively separate the zinc isotopes. High temperature could improve the separation coefficient, while the migration distance has no effect on separation coefficient. The height equivalent to a theoretical plate increase with the increasing of the migration distance. The separation coefficients (68Zn/64Zn=6.03 x 10-4, 66Zn/64Zn=3.52 x 10-4, respectively) and the height equivalent to a theoretical plate (0.204 cm) were obtained by 20 meters chromatographic operation with the temperature of 328 K. (authors)

  18. Glycosylated antitumor ether lipids: activity and mechanism of action.

    Science.gov (United States)

    Arthur, Gilbert; Bittman, Robert

    2014-05-01

    Glycosylated antitumor ether lipids (GAELs) are distinguished from the alkyllysophospholipids or alkylphosphocholines classes of antitumor ether lipids (AEL) by the presence of a sugar moiety. Non-phosphorus GAELs, the subject of this review, have a sugar moiety in place of the phosphobase found in alkyllysophospholipids. Analogues of non-phosphorus GAELs with glucose, maltose, arabinose, or disaccharide moieties have been synthesized. Non-phosphorus GAELs with monosaccharides have cytotoxic and antiproliferative effects against cancer cells derived from a wide range of tissues, including drug resistant cell lines. The most active compound of this group to date is 1-O-hexadecyl-2-O-methyl-3-O-(2'-amino-2'-deoxy-β-D-glucopyranosyl)-sn-glycerol (11), which displays in vitro activity similar to or greater than that of ET-18-OCH3, the AEL "gold" standard. While the detailed molecular mechanism of action of non-phosphorus GAELs is not known, the data indicate that non-phosphorus GAELs are taken up by endocytosis and incorporated into early endosomes. The presence of non-phosphorus GAELs perturbs the maturation of the endocytic vesicles, resulting in the formation of large acidic vacuoles. Cell death appears to be the result of the release of cathepsins from the vacuoles into the cytosol and subsequent activation of a death pathway that is independent of the mitochondria and independent of apoptosis. The ability of these GAELs to kill cells via an apoptosis-independent mechanism makes them prime candidates for development of effective compounds against chemo-resistant tumors and cancer stem cells. The disaccharide-linked GAELs do not have cytotoxic activity but rather inhibit cancer cell motility due to the ability of the compounds to block specific calcium-activated potassium channels in cells. The antitumor activities displayed by these experimental compounds augurs well for their eventual development into clinically useful agents for cancer treatment. PMID:24628233

  19. EXPOSURE TO ETHYLENE GLYCOL MONOBUTYL ETHER AND RELATED WORKERS HABITS IN AN INK FACTORY

    Directory of Open Access Journals (Sweden)

    W. C. Lin, H. Y. Chang, F. H. Chang

    2008-01-01

    Full Text Available Forty six workers from an ink factory were included in this study, in which, passive badge sampler and questionnaire interview were used to assess the concentrations of airborne exposure to ethylene glycol monobutyl ether during work shifts and to understand the subjects' working habits. The geometric mean value (95% confidence interval of the airborne ethylene glycol monobutyl ether concentrations was 0.12(0.08-0.19ppm, with a range of <0.02-1.82ppm. The exposure group was exposed to statistically significantly higher ethylene glycol monobutyl ether concentrations than the control group (geometric mean value: 0.14vs. 0.03ppm; P=0.017. Some chromatograms showed that subjects were co-exposed to m-xylene, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether acetate. According to the completed questionnaires, subjects might also be exposed to 1,2,4,5-tetramethylbenzene, propylene glycol ethers, ethanol, 1,2,4-trimethylbenzene, methanol and diisononyl phthalate. This study also suggests that, the Taiwan occupational time-weighted average level of ethylene glycol monobutyl ether be reconsidered with a view to being lowered.

  20. Absorption of decabromodiphenyl ether and other organohalogen chemicals by grey seals (Halichoerus grypus)

    International Nuclear Information System (INIS)

    An input-output balance study was performed for polybrominated diphenyl ethers, polychlorinated biphenyls and some organochlorine pesticides on three captive, juvenile grey seals (Halichoerus grypus). The animals were fed a diet of herring for six months, during the last three months of which this study was performed. A supplement of decabromodiphenyl ether was included in the diet during the second month of the study. Consistently high absorption (>89%) was observed for all of the chemicals studied, whereas work on other animals has generally shown high (>80%) net absorption at log KOW OW, and very low absorption of decabromodiphenyl ether. The half-life of decabromodiphenyl ether in blood was estimated to be between 8.5 and 13 days. Measurable concentrations of decabromodiphenyl ether were detected in seal blubber at the end of the study, indicating that this chemical can be stored in adipose and may bioaccumulate. Current understanding of the mechanism of absorption of organohalogen chemicals and the potential for accumulation of decabromodiphenyl ether will need reassessing in the light of these results. - Decabromodiphenyl ether is absorbed effectively from the diet by grey seals, and can be stored in the blubber even after exposure ceases

  1. The influence of water mixtures on the dermal absorption of glycol ethers

    International Nuclear Information System (INIS)

    Glycol ethers are solvents widely used alone and as mixtures in industrial and household products. Some glycol ethers have been shown to have a range of toxic effects in humans following absorption and metabolism to their aldehyde and acid metabolites. This study assessed the influence of water mixtures on the dermal absorption of butoxyethanol and ethoxyethanol in vitro through human skin. Butoxyethanol penetrated human skin up to sixfold more rapidly from aqueous solution (50%, 450 mg/ml) than from the neat solvent. Similarly penetration of ethoxyethanol was increased threefold in the presence of water (50%, 697 mg/ml). There was a corresponding increase in apparent permeability coefficient as the glycol ether concentration in water decreased. The maximum penetration rate of water also increased in the presence of both glycol ethers. Absorption through a synthetic membrane obeyed Fick's Law and absorption through rat skin showed a similar profile to human skin but with a lesser effect. The mechanisms for this phenomenon involves disruption of the stratum corneum lipid bilayer by desiccation by neat glycol ether micelles, hydration with water mixtures and the physicochemical properties of the glycol ether-water mixtures. Full elucidation of the profile of absorption of glycol ethers from mixtures is required for risk assessment of dermal exposure. This work supports the view that risk assessments for dermal contact scenarios should ideally be based on absorption data obtained for the relevant formulation or mixture and exposure scenario and that absorption derived from permeability coefficients may be inappropriate for water-miscible solvents

  2. Alternariol 9-methyl ether from the endophytic fungus Alternaria sp. Samif01 and its bioactivities

    Science.gov (United States)

    Lou, Jingfeng; Yu, Ruiting; Wang, Xiaohan; Mao, Ziling; Fu, Linyun; Liu, Yang; Zhou, Ligang

    2016-01-01

    One bioactive compound, identified as alternariol 9-methyl ether, was isolated from the crude extract of the endophytic fungus Alternaria sp. Samif01 residing in the roots of Salvia miltiorrhiza Bunge. Alternariol 9-methyl ether was active against bacteria with minimum inhibitory concentration values ranging from 25 to 75 μg/mL and median inhibitory concentration (IC50) values ranging from 16.00 to 38.27 μg/mL. The IC50 value of alternariol 9-methyl ether against spore germination of Magnaporthe oryzae was 87.18 μg/mL. Alternariol 9-methyl ether also showed antinematodal activity against Bursaphelenchus xylophilus and Caenorhabditis elegans with IC50 values of 98.17 μg/mL and 74.62 μg/mL, respectively. This work is the first report on alternariol 9-methyl ether and its biological activities from the endophytic fungus Alternaria sp. Samif01 derived from S. miltiorrhiza Bunge. The results indicate the potential of Alternaria sp. Samif01 as a source of alternariol 9-methyl ether and also support that alternariol 9-methyl ether is a natural compound with high potential bioactivity against microorganisms. PMID:26887231

  3. Customer exposure to MTBE, TAME, C6 alkyl methyl ethers, and benzene during gasoline refueling.

    OpenAIRE

    Vainiotalo, S; Peltonen, Y; Ruonakangas, A; Pfäffli, P

    1999-01-01

    We studied customer exposure during refueling by collecting air samples from customers' breathing zone. The measurements were carried out during 4 days in summer 1996 at two Finnish self-service gasoline stations with "stage I" vapor recovery systems. The 95-RON (research octane number) gasoline contained approximately 2.7% methyl tert-butyl ether (MTBE), approximately 8.5% tert-amyl methyl ether (TAME), approximately 3.2% C6 alkyl methyl ethers (C6 AMEs), and 0.75% benzene. The individual ex...

  4. NONINVASIVE BRAIN STIMULATION IN TRAUMATIC BRAIN INJURY

    OpenAIRE

    Demirtas-Tatlidede, Asli; Vahabzadeh-Hagh, Andrew M.; Bernabeu, Montserrat; Tormos, Jose M.; Pascual-Leone, Alvaro

    2012-01-01

    Brain stimulation techniques have evolved in the last few decades with more novel methods capable of painless, noninvasive brain stimulation. While the number of clinical trials employing noninvasive brain stimulation continues to increase in a variety of medication-resistant neurological and psychiatric diseases, studies evaluating their diagnostic and therapeutic potential in traumatic brain injury (TBI) are largely lacking. This review introduces different techniques of noninvasive brain s...

  5. Dihydrogenimidazole modified silica-sulfonated poly(ether ether ketone) hybrid materials as electrolyte membranes for direct ethanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, Kimball S.; Hirth, Thomas [Fraunhofer Institute for Interfacial Engineering and Biotechnology, Nobelstr. 12, 70569 Stuttgart (Germany); Schiestel, Thomas, E-mail: Thomas.Schiestel@igb.fraunhofer.de [Fraunhofer Institute for Interfacial Engineering and Biotechnology, Nobelstr. 12, 70569 Stuttgart (Germany)

    2011-05-25

    The present study reports on dihydrogenimidazole modified inorganic-organic mixed matrix membranes for possible application as a proton exchange membrane in direct ethanol fuel cells. The polymeric phase consisted mainly of sulfonated poly(ether ether ketone) (sPEEK) with a sulfonation degree of 55%. The inorganic phase was built up from hydrophilic fumed silica particles interconnected with partially hydrolyzed and condensed tetraethoxysilane with a total inorganic loading of 27.3%. This inorganic phase was further modified with N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole (DHIM), which consists of an hydrolyzable inorganic part and a functional organic group. The influence of the modifier on the mixed matrix system was studied by means of various modifier concentrations in various aqueous-ethanolic systems (water, 2 M and 4 M ethanol). Modifier concentration and ethanol concentration of the ethanol-water mixture exhibited significant but opposite effects on the liquid uptake of the mixed matrix membranes. The proton conductivity as well as the proton diffusion coefficient as a function of modifier content showed a linear decrease. The proton conductivity as a function of temperature showed Arrhenius behavior and the activation energy of the mixed matrix membranes was 43.9 {+-} 2.6 kJ mol{sup -1}. High selectivity of proton diffusion coefficient to ethanol permeability coefficient was obtained with high modifier concentrations. At low modifier concentrations, this selectivity was dominated by ethanol permeation and at high modifier concentrations by proton diffusion. The main electrolyte properties can be optimized by setting the DHIM content in mixed matrix membrane. With this approach, tailor-made membranes can be prepared for possible application in direct ethanol fuel cells.

  6. Composite electrolytes composed of Cs-substituted phosphotungstic acid and sulfonated poly(ether-ether ketone) for fuel cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Song-Yul, E-mail: ms089203@tutms.tut.ac.jp [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Yoshida, Toshihiro; Kawamura, Go [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Muto, Hiroyuki [Department of Materials Science and Engineering, Kurume National College of Technology, 1-1-1 Komorino, Kurume, Fukuoka 830-8555 (Japan); Sakai, Mototsugu [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Matsuda, Atsunori, E-mail: matsuda@tutms.tut.ac.jp [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2010-10-15

    Composite electrolytes composed of cesium hydrogen sulfate containing phosphotungstic acids (CsHSO{sub 4}-H{sub 3}PW{sub 12}O{sub 40}) and sulfonated poly(ether-ether ketone) (SPEEK) were prepared by casting the corresponding precursor for application in fuel cells. Partially Cs-substituted phosphotungstic acids (Cs{sub x}H{sub 3-x}PW{sub 12}O{sub 40}) were formed in the CsHSO{sub 4}-H{sub 3}PW{sub 12}O{sub 40} system by mechanochemical treatment. SPEEK was prepared from PEEK by sulfonation using concentrated sulfuric acid. Flexible composite electrolytes were obtained and their electrochemical properties were markedly improved with the addition of Cs{sub x}H{sub 3-x}PW{sub 12}O{sub 40}, into the SPEEK matrix. A maximum power density of 213 mW cm{sup -2} was obtained from the single cell test for 50H{sub 3}PW{sub 12}O{sub 40}-50CsHSO{sub 4} in SPEEK (1/5 by weight) composite electrolyte at 80 deg. C and at 80 RH%. Electrochemical properties and transmission electron microscopy (TEM) results suggest that three-dimensional cluster particles were formed and homogeneously distributed in the SPEEK matrix. The mechanochemically synthesized Cs{sub x}H{sub 3-x}PW{sub 12}O{sub 40} incorporated into the SPEEK matrix increased the number of protonate sites in the electrolyte. The composite electrolytes were successfully formed with Cs{sub x}H{sub 3-x}PW{sub 12}O{sub 40}, which consist of hydrogen bonding between surface of inorganic solid acids and not only -HSO{sub 4}{sup -} dissociated from CsHSO{sub 4} but also -SO{sub 3}H groups in the SPEEK.

  7. Dispersibility and chemical bonds between multi-walled carbon nanotubes and poly(ether ether ketone) in nanocomposite fibers

    Energy Technology Data Exchange (ETDEWEB)

    Yanmei, Jin, E-mail: jinyanmei818@163.com [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Institute of Functional Fibers, Tianjin Polytechnic University, Tianjin 300387 (China); Haihui, Liu; Ning, Wang; Lichen, Hou [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Institute of Functional Fibers, Tianjin Polytechnic University, Tianjin 300387 (China); Xing-Xiang, Zhang, E-mail: zhangpolyu@gmail.com [Tianjin Municipal Key Lab of Fiber Modification and Functional Fiber, Institute of Functional Fibers, Tianjin Polytechnic University, Tianjin 300387 (China)

    2012-08-15

    A series of multi-walled carbon nanotubes (MWNTs)/poly(ether ether ketone)(PEEK) nanocomposite fibers were fabricated by mixing, melt extruding PEEK with different loadings and species of MWNTs, and melt-spun the blended chips. Nanocomposite fibers were heat-stretched and heat-treated. The morphology and dispersibility of MWNTs in nanocomposite fibers were observed using a field emission environmental scanning electron microscope (FESEM) and a transmission electron microscope (TEM). The thermal and crystallization behavior of nanocomposite fibers were characterized using differential scanning calorimetry (DSC) and an X-ray diffractometer (XRD). Mechanical properties were tested using a tensile strength tester. MWNTs tend to aggregate when the loading exceeds 0.8 wt%. Functional groups on MWNTs improve the hydrophobicity and the dispersibility of MWNTs in PEEK matrix. The enhancement of mechanical properties depends on the loading and species of functional groups. The most effectively reinforced effect is in the sequence, carboxylic MWNTs (MWNT-COOH) > hydroxyl MWNTs (MWNT-OH) > MWNTs, which can be explained by the strong hydrogen bonding and the affinity between MWNT-COOH and PEEK, MWNT-OH and PEEK, and possible formation of a chemical bond between MWNT-COOH and PEEK. A nanocomposite fiber with excellent mechanical property was fabricated using 0.8 wt% MWNT-COOH as filler. The Young's modulus is 1.7 GPa; and the stress is 648 MPa. -- Highlights: Black-Right-Pointing-Pointer Functional groups on MWNTs improve their hydrophobility and dispersability. Black-Right-Pointing-Pointer Mechanical properties depend on the content and species of the functional groups. Black-Right-Pointing-Pointer The reinforced effect is in the sequence, carboxylic MWNTs > hydroxyl MWNTs > MWNTs. Black-Right-Pointing-Pointer The strength behavior was result of hydrogen bond, affinity and chemical bond. Black-Right-Pointing-Pointer Dispersability of MWNTs in matrix was analyzed by

  8. Dispersibility and chemical bonds between multi-walled carbon nanotubes and poly(ether ether ketone) in nanocomposite fibers

    International Nuclear Information System (INIS)

    A series of multi-walled carbon nanotubes (MWNTs)/poly(ether ether ketone)(PEEK) nanocomposite fibers were fabricated by mixing, melt extruding PEEK with different loadings and species of MWNTs, and melt-spun the blended chips. Nanocomposite fibers were heat-stretched and heat-treated. The morphology and dispersibility of MWNTs in nanocomposite fibers were observed using a field emission environmental scanning electron microscope (FESEM) and a transmission electron microscope (TEM). The thermal and crystallization behavior of nanocomposite fibers were characterized using differential scanning calorimetry (DSC) and an X-ray diffractometer (XRD). Mechanical properties were tested using a tensile strength tester. MWNTs tend to aggregate when the loading exceeds 0.8 wt%. Functional groups on MWNTs improve the hydrophobicity and the dispersibility of MWNTs in PEEK matrix. The enhancement of mechanical properties depends on the loading and species of functional groups. The most effectively reinforced effect is in the sequence, carboxylic MWNTs (MWNT–COOH) > hydroxyl MWNTs (MWNT–OH) > MWNTs, which can be explained by the strong hydrogen bonding and the affinity between MWNT–COOH and PEEK, MWNT–OH and PEEK, and possible formation of a chemical bond between MWNT–COOH and PEEK. A nanocomposite fiber with excellent mechanical property was fabricated using 0.8 wt% MWNT–COOH as filler. The Young's modulus is 1.7 GPa; and the stress is 648 MPa. -- Highlights: ► Functional groups on MWNTs improve their hydrophobility and dispersability. ► Mechanical properties depend on the content and species of the functional groups. ► The reinforced effect is in the sequence, carboxylic MWNTs > hydroxyl MWNTs > MWNTs. ► The strength behavior was result of hydrogen bond, affinity and chemical bond. ► Dispersability of MWNTs in matrix was analyzed by calculating solubility parameter.

  9. State of the water in crosslinked sulfonated poly(ether ether ketone). Two-dimensional differential scanning calorimetry correlation mapping

    Energy Technology Data Exchange (ETDEWEB)

    Al Lafi, Abdul G. [Department of Chemistry, Atomic Energy Commission, Damascus, P.O. Box 6091 (Syrian Arab Republic); Hay, James N., E-mail: cscientific9@aec.org.sy [The School of Metallurgy and Materials, College of Physical Sciences and Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2015-07-20

    Highlights: • 2D-DSC mapping was applied to analyze the heat flow responses of hydrated crosslinked sPEEK. • Two types of loosely bond water were observed. • The first was bond to the sulfonic acid groups and increased with ion exchange capacity. • The second was attributed to the polar groups introduced by ions irradiation and increased with crosslinking degree. • DSC combined with 2D mapping provides a powerful tool for polymer structural determination. - Abstract: This paper reports the first application of two-dimensional differential scanning calorimetry correlation mapping, 2D-DSC-CM to analyze the heat flow responses of sulphonated poly(ether ether ketone), sPEEK, films having different ion exchange capacity and degrees of crosslinks. With the help of high resolution and high sensitivity of 2D-DSC-CM, it was possible to locate two types of loosely bound water within the structure of crosslinked sPEEK. The first was bound to the sulfonic acid groups and dependent on the ion exchange capacity of the sPEEK. The second was bound to other polar groups, either introduced by irradiation with ions and dependent on the crosslinking degree or present in the polymer such as the carbonyl groups or terminal units. The results suggest that the ability of the sulfonic acid groups in the crosslinked sPEEK membranes to adsorb water molecules is increased by crosslinking, probably due to the better close packing efficiency of the crosslinked samples. DSC combined with 2D correlation mapping provides a fast and powerful tool for polymer structural determination.

  10. State of the water in crosslinked sulfonated poly(ether ether ketone). Two-dimensional differential scanning calorimetry correlation mapping

    International Nuclear Information System (INIS)

    Highlights: • 2D-DSC mapping was applied to analyze the heat flow responses of hydrated crosslinked sPEEK. • Two types of loosely bond water were observed. • The first was bond to the sulfonic acid groups and increased with ion exchange capacity. • The second was attributed to the polar groups introduced by ions irradiation and increased with crosslinking degree. • DSC combined with 2D mapping provides a powerful tool for polymer structural determination. - Abstract: This paper reports the first application of two-dimensional differential scanning calorimetry correlation mapping, 2D-DSC-CM to analyze the heat flow responses of sulphonated poly(ether ether ketone), sPEEK, films having different ion exchange capacity and degrees of crosslinks. With the help of high resolution and high sensitivity of 2D-DSC-CM, it was possible to locate two types of loosely bound water within the structure of crosslinked sPEEK. The first was bound to the sulfonic acid groups and dependent on the ion exchange capacity of the sPEEK. The second was bound to other polar groups, either introduced by irradiation with ions and dependent on the crosslinking degree or present in the polymer such as the carbonyl groups or terminal units. The results suggest that the ability of the sulfonic acid groups in the crosslinked sPEEK membranes to adsorb water molecules is increased by crosslinking, probably due to the better close packing efficiency of the crosslinked samples. DSC combined with 2D correlation mapping provides a fast and powerful tool for polymer structural determination

  11. Dihydrogenimidazole modified silica-sulfonated poly(ether ether ketone) hybrid materials as electrolyte membranes for direct ethanol fuel cells

    International Nuclear Information System (INIS)

    The present study reports on dihydrogenimidazole modified inorganic-organic mixed matrix membranes for possible application as a proton exchange membrane in direct ethanol fuel cells. The polymeric phase consisted mainly of sulfonated poly(ether ether ketone) (sPEEK) with a sulfonation degree of 55%. The inorganic phase was built up from hydrophilic fumed silica particles interconnected with partially hydrolyzed and condensed tetraethoxysilane with a total inorganic loading of 27.3%. This inorganic phase was further modified with N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole (DHIM), which consists of an hydrolyzable inorganic part and a functional organic group. The influence of the modifier on the mixed matrix system was studied by means of various modifier concentrations in various aqueous-ethanolic systems (water, 2 M and 4 M ethanol). Modifier concentration and ethanol concentration of the ethanol-water mixture exhibited significant but opposite effects on the liquid uptake of the mixed matrix membranes. The proton conductivity as well as the proton diffusion coefficient as a function of modifier content showed a linear decrease. The proton conductivity as a function of temperature showed Arrhenius behavior and the activation energy of the mixed matrix membranes was 43.9 ± 2.6 kJ mol-1. High selectivity of proton diffusion coefficient to ethanol permeability coefficient was obtained with high modifier concentrations. At low modifier concentrations, this selectivity was dominated by ethanol permeation and at high modifier concentrations by proton diffusion. The main electrolyte properties can be optimized by setting the DHIM content in mixed matrix membrane. With this approach, tailor-made membranes can be prepared for possible application in direct ethanol fuel cells.

  12. Synthesis, Characterization and Performance Study of Phosphosilicate Gel-Sulfonated Poly (Ether Ether Ketone Nanocomposite Membrane for Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    S. Ganguly

    2012-03-01

    Full Text Available Phosphosilicate gel – SPEEK (Sulfonated Poly Ether Ether Ketone hybrid nanocomposite membranes are proposed for performance enhancement of polymer electrolyte fuel cell. The nanocomposite membranes are synthesized and characterized at 50 and 60 weight percent of inorganic loading. Phosphosilicate gel particles of varying size (sub micro to nanometer are synthesized using sol gel approach followed by grinding using planetary ball mill for different time. Transmission Electron Microscopy (TEM reveals less than 10 nm particle size for 20 hr grinding. Nano composite membrane having inorganic particles of size less than 10 nm exhibits higher values of proton conductivity, ion exchange capacity and water uptake compared to composite membrane comprising of larger (400 nm and above inorganic particles. The membrane is assembled with the electrode in the unit cell and the polarization characteristics are measured at different operating temperatures. Performance study reveals that between 70 to 80 C the membrane offers best performance in terms of peak power generation and of allowable load current. For the same conditions 40-50 % nano-enhancement of peak power generation is achieved by reducing the average gel particle size from sub micro to less than 10 nm. At medium temperature (between 70 to 80 C the nanocomposite membrane offers more than 100 enhancement of peak power generation compared to that generated by SPEEK membrane. Phosphosilicate gel – SPEEK (Sulfonated Poly Ether Ether Ketone hybrid nanocomposite membranes are proposed for performance enhancement of polymer electrolyte fuel cell. The nanocomposite membranes are synthesized and characterized at 50 and 60 weight percent of inorganic loading. Phosphosilicate gel particles of varying size (sub micro to nanometer are synthesized using sol gel approach followed by grinding using planetary ball mill for different time. Transmission Electron Microscopy (TEM reveals less than 10 nm

  13. Adolescent and Pediatric Brain Tumors

    Science.gov (United States)

    ... abta.org Donate Now Menu Adolescent & Pediatric Brain Tumors Brain Tumors In Children Pediatric Brain Tumor Diagnosis Family ... or Complete our contact form Adolescent & Pediatric Brain Tumors Brain Tumors In Children Pediatric Brain Tumor Diagnosis Family ...

  14. Reduction of Photo Bleaching and Long Term Archiving of Chemically Cleared GFP-Expressing Mouse Brains

    OpenAIRE

    Klaus Becker; Christian Markus Hahn; Saiedeh Saghafi; Nina Jährling; Martina Wanis; Hans-Ulrich Dodt

    2014-01-01

    Tissue clearing allows microscopy of large specimens as whole mouse brains or embryos. However, lipophilic tissue clearing agents as dibenzyl ether limit storage time of GFP-expressing samples to several days and do not prevent them from photobleaching during microscopy. To preserve GFP fluorescence, we developed a transparent solid resin formulation, which maintains the specimens' transparency and provides a constant signal to noise ratio even after hours of continuous laser irradiation. If ...

  15. Chemistry and properties of poly(arylene ether 1,3,4-oxadiazole)s and poly(arylene ether 1,2,4-triazole)s

    Science.gov (United States)

    Connell, J. W.; Hergenrother, P. M.; Wolf, P.

    1992-01-01

    Poly(arylene ether)s containing l,3,4-oxadiazole and 1,2,4-triazole units were prepared by the aromatic nucleophilic displacement reaction of bisphenol oxadiazole and bisphenol triazole compounds with activated aromatic dihalides. The polymers exhibited glass transition temperatures (Tg) ranging from 182 to 242 C, and several polymers exhibited melting transitions (Tm) ranging from 265 to 390 C. Inherent viscosities ranged from 1.02 to 3.40 dl/g, indicating relatively high molecular weights. Thin films exhibited tensile strengths, moduli, and elongations at 23 C of 90-110 MPa, 2.7-3.6 GPa, and 4-7 percent, respectively. Titanium-to-titanium tensile shear specimens of a poly(arylene ether 1,3,4-oxadiazole) exhibited tensile shear strengths at 23 and 150 C of 22.1 and 17.9 MPa, respectively.

  16. Photo- or EB-induced cross-linking reaction of the polymers containing pendant epoxide or vinyl ether groups from glycidyl vinyl ether

    International Nuclear Information System (INIS)

    Polymers containing pendant epoxide or vinyl ether groups were synthesized by radical copolymerization of glycidyl vinyl ether (GVE) with N-phenylmaleimide (NPM) and N-phenoxycarbonyloxymaleimide (NPCM), or by ring-opening alternating copolymerization of GVE with phthalic anhydride (PAn). In the photo-induced cross-linking reaction, the pendant vinyl ether groups in poly(GVE-PAn) showed higher reactivity than the pendant epoxide groups in poly(GVE-NPM), and poly(GVE-PAn) was readily cross-linked by various dithiols with or without benzophenone. In the electron beam (EB)-induced cross-linking reaction, the sensitivity of poly(GVE-NPCM), which has pendant epoxide and carbonate groups, was higher than that of poly(GVE-NPM) containing only pendant epoxide groups. Furthermore, the EB-sensitivity of poly(GVE-PAn) was even higher than that of poly(GVE-NPM) or poly(GVE-NPCM). (author)

  17. Solvent Effects on Cesium Complexation with Crown Ethers from Liquid to Supercritical Fluids

    International Nuclear Information System (INIS)

    Nuclear magnetic resonance (NMR) techniques were used to study crown ether-water interactions in solvents of low dielectric constants such as chloroform and carbon tetrachloride. Water forms a 1:1 complex with a number of crown ethers including 12-crown-4, 15-crown-5, 18-crown-6, dicyclohexano-18=crown-6, dicyclohexano-24-crown 8, and dibenzl-24-crown-8 in chloroform. Among these crown ethers, the 18-crown-6-H2 complex has the largest equilibrium constant (K=545) and 97% of the crown is complexed to water in chloroform. Addition of carbon tetrachloride to chloroform lowers the equilibrium constants of the crown-water complexes. The partition coefficients of crown ethers (D=crown in water/crown in solvent) between water and organic solvent also vary with solvent composition

  18. SYNTHESIS, COMPLEXATION BEHAVIOR AND REACTIONS OF THIA-CROWN ETHERS INCORPORATING PROPAN-2-ONE UNITS

    NARCIS (Netherlands)

    KELLOGG, RM; VANBOLHUIS, F

    1991-01-01

    Thia-crown ethers containing ketone functionality derived from 1,3-dichloroacetone have been prepared in 70-80% yields; the crystal structures of one free macrocycle and two Ag1 complexes have been determined.

  19. IRIS Toxicological Review of Ethylene Glycol Mono-Butyl Ether (Egbe) (External Review Draft)

    Science.gov (United States)

    EPA has conducted a peer review of the scientific basis supporting the human health hazard and dose-response assessment of ethylene glycol monobutyl ether that will appear on the Integrated Risk Information System (IRIS) database.

  20. IRIS Toxicological Review of Ethylene Glycol Mono-Butyl Ether (EGBE) (Interagency Science Discussion Draft)

    Science.gov (United States)

    EPA is releasing the draft report, Toxicological Review for Ethylene Glycol Mono-Butyl Ether , that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the IRIS Assessme...

  1. Degradation of the Alternaria mycotoxins alternariol, alternariol monomethyl ether, and altenuene upon bread baking.

    Science.gov (United States)

    Siegel, David; Feist, Michael; Proske, Matthias; Koch, Matthias; Nehls, Irene

    2010-09-01

    The stability of the Alternaria mycotoxins alternariol, alternariol monomethyl ether, and altenuene upon bread baking was investigated by model experiments using a spiked wholemeal wheat flour matrix. For alternariol and alternariol monomethyl ether, but not for altenuene, degradation products, formed through a sequence of hydrolysis and decarboxylation, could be identified in pilot studies. The simultaneous quantification of alternariol, alternariol monomethyl ether, altenuene, and the degradation products was achieved by a newly developed high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) multimethod. The obtained quantitative data indicate that the Alternaria mycotoxins are barely degraded during wet baking, while significant degradation occurs upon dry baking, with the stability decreasing in the order alternariol monomethyl ether>alternariol>altenuene. The novel degradation products could be detected after the wet baking of flour spiked with alternariol and in a sample survey of 24 commercial cereal based baking products. PMID:20687560

  2. First Synthesis of 2α-Thiol Ether Analog of Docetaxel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A 2α-phenylthio ether analog 1c of docetaxel was synthesized for the first time from 10-deacetylbaccatin Ⅲ 3 via double inversion of C-2 configuration. This compound showed very weak cytotoxicity toward several tumor cell lines.

  3. Synthesis and biological evaluation of arctigenin ester and ether derivatives as activators of AMPK.

    Science.gov (United States)

    Shen, Sida; Zhuang, Jingjing; Chen, Yijia; Lei, Min; Chen, Jing; Shen, Xu; Hu, Lihong

    2013-07-01

    A series of new arctigenin and 9-deoxy-arctigenin derivatives bearing different ester and ether side chains at the phenolic hydroxyl positions are designed, synthesized, and evaluated for activating AMPK potency in L6 myoblasts. Initial biological evaluation indicates that some alkyl ester and phenethyl ether arctigenin derivatives display potential activities in AMPK phosphorylation improvement. Further structure-activity relationship analysis shows that arctigenin ester derivatives 3a, 3h and 9-deoxy-arctigenin phenethyl ether derivatives 6a, 6c, 6d activate AMPK more potently than arctigenin. Moreover, the 2-(3,4-dimethoxyphenyl)ethyl ether moiety of 6c has been demonstrated as a potential functional group to improve the effect of AMPK phosphorylation. The structural optimization of arctigenin leads to the identification of 6c as a promising lead compound that exhibits excellent activity in AMPK activation. PMID:23673223

  4. The electromagnetic ether, as a medium of the existence of electromagnetic waves

    Directory of Open Access Journals (Sweden)

    P. O. Demjanenko

    2010-12-01

    Full Text Available We propose a new approach to the problem, according to which the revision is subject to the very concept of ether, which should not be viewed as filling, as well as an integral part of the universe.

  5. Template synthesis and cocatalytic behavior of phosphorus donor containing trans-Fe(O) metallacrown ethers

    Institute of Scientific and Technical Information of China (English)

    XU, Feng-Bo; ZHANG, Li-Fang; SUN, Li-Juan; XUAN, Zhen-Ai; ZHANG, Zheng-Zhi; ZHAO, Wei-Jun

    2000-01-01

    Some new phosphorus donors containing trabs-Fe (0) metal lacrown ethers were obtained by template synthesis. The co catalytic properties of these complexes and the X-ray diffrac tion structure of complex 1 were discussed.

  6. American Brain Tumor Association

    Science.gov (United States)

    ... For Health Care Professionals About Us Our Founders Board of Directors Staff Leadership Strategic Plan Financials News Careers Brain Tumor Information Brain Anatomy Brain Tumor Symptoms Diagnosis Types of Tumors Tumor Grade Risk Factors Brain Tumor Statistics ABTA Publications Brain Tumor ...

  7. Brain Tumor Surgery

    Science.gov (United States)

    ... Pediatric Caregiver Resource Center About Us Our Founders Board of Directors Staff Leadership Strategic Plan Financials News Careers Brain Tumor Information Brain Anatomy Brain Tumor Symptoms Diagnosis Types of Tumors Tumor Grade Risk Factors Brain Tumor Statistics ABTA Publications Brain Tumor ...

  8. Anatomy of the Brain

    Science.gov (United States)

    ... Dictionary Webinars Anytime Learning About Us Our Founders Board of Directors Staff Leadership Strategic Plan Financials News Careers Brain Tumor Information Brain Anatomy Brain Tumor Symptoms Diagnosis Types of Tumors Tumor Grade Risk Factors Brain Tumor Statistics ABTA Publications Brain Tumor ...

  9. EXPOSURE TO ETHYLENE GLYCOL MONOBUTYL ETHER AND RELATED WORKERS HABITS IN AN INK FACTORY

    OpenAIRE

    W. C. Lin, H. Y. Chang, F. H. Chang

    2008-01-01

    Forty six workers from an ink factory were included in this study, in which, passive badge sampler and questionnaire interview were used to assess the concentrations of airborne exposure to ethylene glycol monobutyl ether during work shifts and to understand the subjects' working habits. The geometric mean value (95% confidence interval) of the airborne ethylene glycol monobutyl ether concentrations was 0.12(0.08-0.19)ppm, with a range of

  10. SYNTHESIS OF TERMINAL EPOXY FUNCTIONAL SILOXANES FOR MODIFICATION OF DIGLYCIDYL ETHER OF BIS-PHENOL A

    OpenAIRE

    Jenish Paul*,; A. Benny Cherian,

    2015-01-01

    In this study, terminal epoxy functional poly dimethyl siloxanes (TEF PDMS) were synthesized by the hydrosilylation reaction of terminal silyl hydride functional with allyl glycidyl ether. The hydrosilylation reaction was characterized by FTIR and NMR. Samples of modified and unmodified PDMS were blended with commercial epoxy resin, diglycidyl ether of bis-phenol A (DGEBA), at various ratios using a polyamine as curing agent. Their damping and thermal properties were studied by DM...

  11. Interaction of Polybrominated Diphenyl Ethers and Aerobic Granular Sludge: Biosorption and Microbial Degradation

    OpenAIRE

    Shou-Qing Ni; Qingjie Cui; Zhen Zheng

    2014-01-01

    As a new category of persistent organic pollutants, polybrominated diphenyl ethers (PBDEs) have become ubiquitous global environmental contaminants. No literature is available on the aerobic biotransformation of decabromodiphenyl ether (BDE-209). Herein, we investigated the interaction of PBDEs with aerobic granular sludge. The results show that the removal of BDE-209 from wastewater is mainly via biosorption onto aerobic granular sludge. The uptake capacity increased when temperature, contac...

  12. Imidazole-containing triblock copolymers with a synergy of ether and imidazolium sites

    OpenAIRE

    Jangu, Chainika; Wang, Jing-Han Helen; Wang, Dong; Fahs, Gregory B.; Heflin, James R.; Robert B. Moore; Colby, Ralph H.; Long, Timothy E.

    2015-01-01

    Reversible addition-fragmentation chain transfer (RAFT) polymerization enabled the synthesis of well-defined A-BC-A triblock copolymers containing a synergy of pendant ether and imidazolium sites. The soft central BC block comprises low Tg di(ethylene glycol) methyl ether methacrylate (DEGMEMA) and 1-(4-vinylbenzyl) methyl imidazolium units. External polystyrene blocks provide mechanical reinforcement within a nanoscale morphology. Dynamic mechanical analysis (DMA) of the A-BC-A triblock copo...

  13. Procedure for selective solvent extraction of superheavy elements 113+ and 1142+ by use of crown ethers

    International Nuclear Information System (INIS)

    Solvent extraction of Pb2+ and Ba2+ with 18-crown-6 ethers from a solution containing Ce3+, Zn2+ and UO22+ ions in the presence of sodium picrate was studied. The results allow to suggest the use of crown ethers as a selective reagent for the separation of elements having ionic radii near to those predicted for the superheavy elements 113+ and 1142+. This extraction may be also used for continuous chemical separations in accelerator experiments. (orig.)

  14. Influence of the Functionalization Degree of Acidic Ion-Exchange Resins on Ethyl Octyl Ether Formation

    OpenAIRE

    Guilera, J.; Hanková, L. (Libuše); Jeřábek, K. (Karel); Ramírez, E.; Tejero, J.

    2014-01-01

    Ethyl octyl ether (EOE) can be obtained by the ethylation of 1-octanol by means of ethanol or diethyl carbonate over acidic ion-exchange resins. However, EOE formation has to compete with the less steric demanding formation of diethyl ether, by-product obtained from ethanol dehydration or diethyl carbonate decomposition. In the present work, the influence of the resin functionalization degree on EOE formation has been evaluated. A series of partially sulfonated resins were prepared by the sul...

  15. Metal ion complexation by ionizable crown ethers. Final report, January 1, 1988--June 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, R.A.

    1994-12-31

    During the report period a variety of new lipophilic ionizable crown ethers with pendent proton-ionizable groups has been synthesized. The ligands possess one or more ionizable group (carboxylic acid, phosphonic acid monoethyl ester, para-nitrophenol, phosphonic acid) attached to crown ether, monoazacrown ether or diazacrown ether frameworks. These novel chelating agents have either pendent or inward-facing proton-ionizable groups. Such lipophilic proton-ionizable crown ethers are designed for use in multiphase metal ion separations (solvent extraction, liquid membrane transport). In addition a series of proton-ionizable crown ethers without lipophilic groups was prepared to study how structural variations within the ligand influence metal ion complexation in homogeneous media as assessed by NMR spectroscopy or titration calorimetry. A third class of new metal ion-complexing agents is a series of lipophilic acyclic polyether dicarboxylic acids. Competitive solvent extractions of alkali metal and alkaline earth cations and of the mixed species have been conducted to reveal the influence of ring size, nature and attachment site of the lipophilic group, sidearm length, and proton-ionizable group identity and location upon the selectivity and efficiency of metal ion complexation. In addition to such studies of structural variation within the lipophilic proton-ionizable crown ether, the effect of changing the organic solvent and variation of the stripping conditions have been assessed. The influence of structural variations within lipophilic acyclic polyether dicarboxylic acids upon competitive solvent extraction of alkaline earth cations has been probed. Also a new chromogenic, di-ionizable crown ether with extremely high selectivity for Hg{sup 2+} has been discovered.

  16. Carbamate-directed benzylic lithiation for the diastereo- and enantioselective synthesis of diaryl ether atropisomers

    Directory of Open Access Journals (Sweden)

    Abigail Page

    2011-09-01

    Full Text Available Diaryl ethers carrying carbamoyloxymethyl groups may be desymmetrised enantio- and diastereoselectively by the use of the sec-BuLi–(−-sparteine complex in diethyl ether. Enantioselective deprotonation of one of the two benzylic positions leads to atropisomeric products with ca. 80:20 e.r.; an electrophilic quench typically provides functionalised atropisomeric diastereoisomers in up to 97:3 d.r.

  17. Influence of ethereal oils extracted from Lamiaceae family plants on some pathogen microorganisms

    OpenAIRE

    Klaus Anita S.; Beatović Damir V.; Nikšić Miomir P.; Jelačić Slavica Ć.; Nedović Viktor K.; Petrović Tanja S.

    2008-01-01

    As pathogen microorganisms can be found in different kinds of food, using of natural antimicrobial compounds, like ethereal oils, could be important in the preservation of different groceries. To evaluate antimicrobial activity of ethereal oils extracted from Lamiaceae family plants - Rosmarinus officinalis L., Thymus vulgaris L., Majorana hortensis M o e n c h, and Salvia officinalis L screening of their effects against food borne bacteria Staphylococcus aureus, Enterococcus faecalis, Proteu...

  18. Determination of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether in human urine by HS-SPME gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are oxygenated compounds added to gasoline to enhance octane rating and to improve combustion. They may be found as pollutants of living and working environments. In this work a robotized method for the quantification of low level MTBE, ETBE and TAME in human urine was developed and validated. The analytes were sampled in the headspace of urine by SPME in the presence of MTBE-d12 as internal standard. Different fibers were compared for their linearity and extraction efficiency: carboxen/polydimethylsiloxane, polydimethylsiloxane/divinylbenzene, and polydimethylsiloxane. The first, although highly efficient, was discarded due to deviation of linearity for competitive displacement, and the polydimethylsiloxane/divinylbenzene fiber was chosen instead. The analysis was performed by GC/MS operating in the electron impact mode. The method is very specific, with range of linearity 30-4600 ng L-1, within- and between-run precision, as coefficient of variation, -1 for all the analytes. The influence of the matrix on the quantification of these ethers was evaluated analysing the specimens of seven traffic policemen exposed to autovehicular emissions: using the calibration curve and the method of standard additions comparable levels of MTBE (68-528 ng L-1), ETBE (-1), and TAME (-1) were obtained

  19. Brain and Nervous System

    Science.gov (United States)

    ... to Know About Zika & Pregnancy Brain and Nervous System KidsHealth > For Parents > Brain and Nervous System Print ... is quite the juggler. Anatomy of the Nervous System If you think of the brain as a ...

  20. Brain tumor (image)

    Science.gov (United States)

    Brain tumors are classified depending on the exact site of the tumor, the type of tissue involved, benign ... tendencies of the tumor, and other factors. Primary brain tumors can arise from the brain cells, the meninges ( ...

  1. Traumatic Brain Injury

    Science.gov (United States)

    Traumatic brain injury (TBI) happens when a bump, blow, jolt, or other head injury causes damage to the brain. Every year, millions of people in the U.S. suffer brain injuries. More than half are bad enough that ...

  2. Genetic Brain Disorders

    Science.gov (United States)

    A genetic brain disorder is caused by a variation or a mutation in a gene. A variation is a different form of a ... is a change in a gene. Genetic brain disorders affect the development and function of the brain. ...

  3. Traumatic Brain Injury

    Science.gov (United States)

    Traumatic brain injury (TBI) happens when a bump, blow, jolt, or other head injury causes damage to the brain. Every year, millions of people in the U.S. suffer brain injuries. More than half are bad enough that people ...

  4. Development and evaluation of stavudine niosome by ether injection method

    Directory of Open Access Journals (Sweden)

    H. M. Shreedevi

    2016-01-01

    Full Text Available The main objective of the present study was to encapsulate Stavudine in niosomes for achieving prolonged release & longer duration of action. Niosome are now widely studied as an alternative delivery system to liposome. An increasing number of non ionic surfactant has been found to form vesicles, capable of entrapping hydrophilic and hydrophobic molecules. stavudine drug has shorter half life, Negligible protein binding. This drawback was decreased by formulating it as niosomes. In our present study we incorporated Stavudine into niosome by using ether injection method. In evaluation study the effect of the varying composition of non ionic surfactant and cholesterol on the properties such as zeta potential, drug content, vesicle size and drug release were studied. The result of the physiochemical characterisation and in vitro permeation studies of the prepared vesicles by dialysis membrane to get the idea of drug release. From the present investigation, it can be concluded that the developed niosome formulation of stavudine has shown great potential in the treatment of HIV by providing a prolonged release profile.

  5. Phthalates and polybrominated diphenyl ethers in retail stores

    Science.gov (United States)

    Xu, Ying; Liang, Yirui; Urquidi, Jorge R.; Siegel, Jeffrey A.

    2014-04-01

    Retail stores contain a wide range of products that can emit a variety of indoor pollutants. Among these chemicals, phthalate esters and polybrominated diphenyl ethers (PBDEs) are two important categories, because they are extensively used as additives in consumer products and associated with serious health concerns. This study measured six phthalate and 14 PBDE compounds inside of 12 retail stores in Texas and Pennsylvania, U.S. Phthalates and PBDEs were widely found in the retail environment, indicating that they are ubiquitous indoor air pollutants. DEP, DnBP, and DEHP were the most abundant phthalates, with DnBP showing the highest concentration (0.23 ± 0.36 μg m-3). PBDEs were dominated by BDE-28, -99, and -209, having concentrations as high as 0.85 ± 1.99 ng m-3 (BDE-99). The levels of phthalates and PBDEs measured in this study are comparable to concentrations found in previous investigations of residential buildings, with phthalates showing lower concentrations and PBDEs exhibiting higher concentrations in retail stores. The potential co-occurrence of phthalates was not as strong as that of PBDEs, suggesting that phthalates might have more diverse sources. Whole building emission rates were calculated and showed similar patterns of variations as indoor air concentrations, suggestion the diversity of indoor sources of phthalates and PBDEs in retail environments.

  6. Crown ethers and phase transfer catalysis in polymer science

    CERN Document Server

    Carraher, Charles

    1984-01-01

    Phase transfer catalysis or interfacial catalysis is a syn­ thetic technique involving transport of an organic or inorganic salt from a solid or aqueous phase into an organic liquid where reaction with an organic-soluble substrate takes place. Over the past 15 years there has been an enormous amount of effort invested in the development of this technique in organic synthe­ sis. Several books and numerous review articles have appeared summarizing applications in which low molecular weight catalysts are employed. These generally include either crown ethers or onium salts of various kinds. While the term phase transfer catalysis is relatively new, the concept of using a phasetrans­ fer agent (PTA) is much older~ Both Schnell and Morgan employed such catalysts in synthesis of polymeric species in the early 1950's. Present developments are really extensions of these early applications. It has only been within the last several years that the use of phase transfer processes have been employed in polymer synthesis...

  7. Searching for Trans Ethyl Methyl Ether in Orion KL

    CERN Document Server

    Tercero, B; López, A; Brouillet, N; Kolesniková, L; Motiyenko, R A; Margulès, L; Alonso, J L; Guillemin, J -C

    2015-01-01

    We report on the tentative detection of $trans$ Ethyl Methyl Ether (tEME), $t-CH_3CH_2OCH_3$, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for $gauche$-$trans$-n-propanol, $Gt-n-CH_3CH_2CH_2OH$, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are $\\leq(4.0\\pm0.8)\\times10^{15} cm^{-2}$ and $\\leq(1.0\\pm0.2)\\times10^{15} cm^{-2}$ for tEME and Gt-n-propanol, respectively. The rotational temperature is $\\sim100 K$ for both molecules. We also provide maps of $CH_3OCOH$, $CH_3CH_2OCOH$, $CH_3OCH_3$, $CH_3OH$, a...

  8. Synthesis and Characterization of Poly (Arylene Ether Benzimidazole) Oligomers

    Science.gov (United States)

    Leonard, Michael J.

    1995-01-01

    Several poly(arylene ether benzimidazole) oligomers were prepared by the nucleophilic aromatic substitution reaction of a bisphenol benzimidazole and various alkyl-substituted aromatic bisphenols with an activated aromatic dihalide in N, N-dimethylacetarnide. Moderate to high molecular weight terpolymers were obtained in all cases, as shown by their inherent viscosities, which ranged from 0.50 to 0.87 dL g(sup -1). Glass transition temperatures (T(sub g)s) of polymer powders ranged from 267-280 C. Air-dried unoriented thin film T(sub g)s were markedly lower than those of the powders, whereas T(sub g)s of films dried in a nitrogen atmosphere were identical to those of the corresponding powders. In addition, air-dried films were dark amber and brittle, whereas nitrogen-dried films were yellow and creasable. Nitrogen-dried films showed slightly higher thin-film tensile properties than the air-dried films, as well.

  9. Children's exposure to polybrominated diphenyl ethers (PBDEs) through mouthing toys.

    Science.gov (United States)

    Ionas, Alin C; Ulevicus, Jocelyn; Gómez, Ana Ballesteros; Brandsma, Sicco H; Leonards, Pim E G; van de Bor, Margot; Covaci, Adrian

    2016-02-01

    Polybrominated diphenyl ethers (PBDEs) have previously been detected in children toys, yet the risk of child exposure to these chemicals through the mouthing of toys or other items is still unknown. We aimed to expand on the current knowledge by investigating the impact of infants' mouthing activities on exposure to PBDEs present in toys. This was established by a leaching model for determining the amount PBDEs that can leach from toys into saliva in simulated conditions. The PBDE migration rate was at its highest for the 15 min low-exposure scenario incubations (198 pg/cm(2) × min) with the ERM EC-591 certified reference material (CRM) (0.17% w/w PBDEs). The leaching process was congener-dependent, since the percentage of lower brominated PBDE congeners that leached out was up to 4.5 times higher than for the heavier PBDEs. To study the scenario in which a child would mouth on a toy flame retarded with BDE 209 alone, a plastic item containing 7% BDE 209 (w/w) was also tested. The BDE 209 amounts leached out in only 15 min were higher than the amounts leached from the CRM after the 16 h incubation. For the Belgian population, the exposure scenario from mouthing on toys containing PBDEs in amounts similar to the REACH threshold was found to be lower than the exposure from mother's milk, but higher than the exposure through diet or even dust. PMID:26655676

  10. Maternal-infant transfer of polybrominated diphenyl ethers

    Energy Technology Data Exchange (ETDEWEB)

    Hirai, T.; Fujimine, Y.; Watanabe, S. [Otsuka Pharmaceutical Co., Ltd., Tokushima (Japan); Nakamura, Y. [SRL Nishinihon, Fukuoka (Japan); Shimomura, H. [Shimomura OBGY Clinic, Fukuoka (Japan); Nagayama, J. [Kyushu Univ., Fukuoka (Japan)

    2004-09-15

    Polybrominated diphenyl ethers (PBDEs) are widely used brominated flame retardants (BFRs) in plastics of automobiles, textile industry, television, personal computer, electronic appliances etc. The amount of production world-wide has reached 40,000 tons in 1992. In 1992 world-wide production of PBDEs reached 40,000 tons raising serious concern over the dangers of environmental pollution by BFRs. The toxicity of PBDEs was reported to be an antagonist of thyroid-hormone (T4) and inhibition to aryl hydrocarbon (Ah) receptor. Since PBDEs are structurally similar to PCBs and therefore they work as an antagonist. Polychlorinated biphenyl (PCBs) demonstrate biological stability and high lipophilicity. As a result, PCBs used in the past and released into the environment, have been transmitted through the food chain and accumlated in the human body over time. In Japan, approximately 58,000 tons of PCBs were produced with the grade name of Kanechlor in between 1954 and 1971. In this study, all PCB congeners and 25 PBDE congeners (17, 25, 28, 30, 32, 33, 35, 37, 47, 49, 66, 71, 75, 77, 85, 99, 100, 116, 119, 126, 138, 153, 154, 155, 166) were analyzed by the method that combines high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). The purpose of this study was to investigate whether congener-specific PCBs and PBDEs were transferred from pregnant women to their infants.

  11. Solubility of sulphur dioxide in mixed polyethylene glycol dimethyl ethers

    International Nuclear Information System (INIS)

    The purpose of this study is to discuss the harmful effects of increased sulphur dioxide in the atmosphere, to select an appropriate solvent for the regenerable removal of sulphur dioxide from tail gas streams, to collect solubility data over a wide range of temperatures and pressures, and to correlate the results for use in the design of these facilities. Excess enthalpy and the partial molar enthalpies of solution/absorption and mixing were also calculated from the solubility data and were examined in the context of solubility enhancement and solvent-solute interactions. The effect of water on the solubility of sulphur dioxide was also investigated with a 6.04 mass per cent water solution. Overall results showed that the best solvents for sulphur dioxide have been those with a good donor ability. DMEPEG, a mixture of dimethyl ether polyethylene glycol has been recommended because it satisfies the criteria for a good sulphur dioxide removal solvent and because of the many other advantageous properties it has for regenerable sulphur dioxide removal. It was concluded that the solubility data, the correlated results and the calculated enthalpies of solution and mixing can be used in evaluating and designing a potential sulphur dioxide removal facility with DMEPEG. 77 refs., 10 tabs., 9 figs., 1 appendix

  12. Thermochemical biorefinery based on dimethyl ether as intermediate: Technoeconomic assessment

    International Nuclear Information System (INIS)

    Highlights: ► A thermochemical biorefinery based on bio-DME as intermediate is studied. ► The assessed concepts (12) lead to multi-product generation (polygeneration). ► In all concepts DME is converted by carbonylation or hydrocarbonylation. ► Rates of return are similar to or higher than plants producing a single product. -- Abstract: Thermochemical biorefinery based on dimethyl ether (DME) as an intermediate is studied. DME is converted into methyl acetate, which can either be hydrogenated to ethanol or sold as a co-product. Considering this option together with a variety of technologies for syngas upgrading, 12 different process concepts are analyzed. The considered products are ethanol, methyl acetate, H2, DME and electricity. The assessment of each alternative includes biomass pretreatment, gasification, syngas clean-up and conditioning, DME synthesis and conversion, product separation, and heat and power integration. A plant size of 500 MWth processing poplar chips is taken as a basis. The resulting energy efficiency to products ranges from 34.9% to 50.2%. The largest internal rate of return (28.74%) corresponds to a concept which produces methyl acetate, DME and electricity (exported to grid). A sensitivity analysis with respect to total plant investment (TPI), total operation costs (TOC) and market price of products was carried out. The overall conclusion is that, despite its greater complexity, this kind of thermochemical biorefinery is more profitable than thermochemical bioprocesses oriented to a single product.

  13. Selective pressurized liquid extraction of polybrominated diphenyl ethers in fish.

    Science.gov (United States)

    Losada, S; Santos, F J; Galceran, M T

    2009-12-15

    A fast and simple method for the analysis of polybrominated diphenyl ethers (PBDEs) in fish samples was developed using a one-step extraction and clean-up by means of pressurized liquid extraction (PLE) combined with gas chromatography-ion trap tandem mass spectrometry (GC-ITMS-MS). The selective PLE method provided to obtain ready-to-analyse extracts without any additional clean-up step, using a sorbent as fat retainer inside the PLE cell. Several PLE operating conditions, such as solvent type, extraction temperature and time, number of cycles and type of fat retainer, were studied. Using Florisil as fat retainer, maximum recoveries of PBDEs (83-108%) with minimum presence of matrix-interfering compounds were obtained using a mixture of n-hexane:dichloromethane 90:10 (v/v) as solvent, an extraction temperature of 100 degrees C and a static extraction time of 5 min in combination with three static cycles. Quality parameters of the method were established using standards and fish samples. Limits of detection and quantification ranged from 10 to 34 pg g(-1) wet weight and between 34 and 68 pg g(-1) wet weight, respectively. In addition, good linearity (between 1 and 500 ng ml(-1)) and high precision (RSD %<15%) were achieved. The method was validated using the standard reference material SRM-1945 (whale blubber) and was then applied to the analysis of PBDEs in fish samples. PMID:19836561

  14. Experimental Research on Flash Boiling Spray of Dimethyl Ether

    Institute of Scientific and Technical Information of China (English)

    Peng Zhang

    2014-01-01

    The high-speed digital imaging technique is applied to observe the developing process of flash boiling spray of dimethyl ether at low ambient pressure, and the effects of nozzle opening pressure and nozzle hole diameter on the spray shape, spray tip penetration and spray angle during the injection are investigated. The experimental results show that the time when the vortex ring structure of flash boiling spray forms and its developing process are determined by the combined action of the bubble growth and breakup in the spray and the air drag on the leading end of spray;with the enhancement of nozzle opening pressure, the spray tip penetration increases and the spray angle decreases. The influence of nozzle hole diameter on the spray tip penetration is relatively complicated, the spray tip penetration is longer with a smaller nozzle hole diameter at the early stage of injection, while the situation is just opposite at the later stage of injection. This paper establishes that the variation of spray angle is consistent with that of nozzle hole diameter.

  15. Hydrogen production from dimethyl ether using corona discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Ji-Jun; Liu, Chang-Jun [Key Laboratory for Green Chemical Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Zhang, Yue-Ping [Department of Chemistry, Tianjin University, Tianjin 300072 (China)

    2007-01-01

    Dimethyl ether (DME), with its non-toxic character, high H/C ratio and high-energy volumetric density, is an ideal resource for hydrogen production. In this work, hydrogen production from the decomposition of DME using corona discharge has been studied. The corona discharge plasma decomposition was conducted at ambient conditions. The effects of dilution gas (argon), flow rate, frequency and waveforms on the DME decomposition were investigated. The addition of dilution gas can significantly increase the hydrogen production rate. The highest hydrogen production rate with the lowest energy consumption presents at the flow rate of 27.5Nmlmin{sup -1}. AC voltage is more favored than DC voltage for the production of hydrogen with less energy input. The optimal frequency is 2.0kHz. The hydrogen production rate is also affected by the input waveform and decreases as following: sinusoid triangular>sinusoid>ramp>square, whereas the sinusoid waveform shows the highest energy efficiency. The corona discharge decomposition of DME is leading to a simple, easy and convenient hydrogen production with no needs of catalyst and external heating. (author)

  16. Methyltert-butyl Ether (MTBE Degradation by a Microbial Consortium

    Directory of Open Access Journals (Sweden)

    S. B. Mortazavi

    2005-01-01

    Full Text Available Methyl tert-butyl ether (MTBE is added to reformulated gasoline to meet the 1990 Clean Air Act directives. Widespread use of MTBE in gasoline has resulted in groundwater contamination. Because of its undesirable effects on drinking water and ecologically harmful effects, MTBE removal has become a public health and environmental concern. In this study, we have isolated a mixed bacterial culture which is capable of degrading the MTBE as a sole carbon and energy source. This consortium was developed from mixed urban and petrochemical activated sludge after 4 month's enrichment. Enrichment was conducted in batch reactor, fitted with a screw cap and butyl rubber septum. MTBE concentration was measured in head space by gas chromatography. Degradation was determined by MTBE removal. MTBE biodegradation was depended to Dissolved Oxygen (DO concentration and not affected by the changes in concentration of trace element solution or other stimulator Substances. Degradation rates were nearly 1.478 mg MTBE h-1 g-1 (wet biomass and didn't change with MTBE concentration (up 500 mg L-1.

  17. The effect of ether anesthesia on fin-clipping rate

    Science.gov (United States)

    Eschmeyer, Paul H.

    1953-01-01

    As part of an experimental program to learn the effects of stocking lake trout (Salvelinus namaycush) in Lake Superior, 141, 392 fingerlings were marked at the Charlevoix (Michigan) Station of the U.S. Fish and Wildlife Service in October 1952. The adipose fin was removed from all fish, the right pelvic from the remainder. A random sample of 2, 417 of the fish showed an average total length of 4.0 inches (range, 2.7 to 5.4). The mean weight of all fish marked was slightly less than one-third ounce (49 fish per pound). The local women, none of whom had previous experience in the work, were employed to mark the fish. Bone-cutting forceps were used for excision of the fins, and each worker wore a bobbinet glove to facilitate handling of the fish. On alternate days the fish were anesthetized with ether before marking, to determine the effect of its use on the fin-clipping rate.

  18. Mitochondrial dysfunction and defects in lipid homeostasis as therapeutic targets in neurodegeneration with brain iron accumulation

    Science.gov (United States)

    Kinghorn, Kerri J.; Castillo-Quan, Jorge Iván

    2016-01-01

    ABSTRACT The PLA2G6 gene encodes a group VIA calcium independent phospholipase A2 (iPLA2β), which hydrolyses glycerophospholipids to release fatty acids and lysophospholipids. Mutations in PLA2G6 are associated with a number of neurodegenerative disorders including neurodegeneration with brain iron accumulation (NBIA), infantile neuroaxonal dystrophy (INAD), and dystonia parkinsonism, collectively known as PLA2G6-associated neurodegeneration (PLAN). Recently Kinghorn et al. demonstrated in Drosophila and PLA2G6 mutant fibroblasts that loss of normal PLA2G6 activity is associated with mitochondrial dysfunction and mitochondrial lipid peroxidation. Furthermore, they were able to show the beneficial effects of deuterated polyunsaturated fatty acids (D-PUFAs), which reduce lipid peroxidation. D-PUFAs were able to rescue the locomotor deficits of flies lacking the fly ortholog of PLA2G6 (iPLA2-VIA), as well as the mitochondrial abnormalities in PLA2G6 mutant fibroblasts. This work demonstrated that the iPLA2-VIA knockout fly is a useful organism to dissect the mechanisms of pathogenesis of PLAN, and that further investigation is required to determine the therapeutic potential of D-PUFAs in patients with PLA2G6 mutations. The fruit fly has also been used to study some of the other genetic causes of NBIA, and here we also describe what is known about the mechanisms of pathogenesis of these NBIA variants. Mitochondrial dysfunction, defects in lipid metabolism, as well as defective Coenzyme A (CoA) biosynthesis, have all been implicated in some genetic forms of NBIA, including PANK2, CoASY, C12orf19 and FA2H.

  19. Left Brain, Right Brain: Facts and Fantasies

    OpenAIRE

    Corballis, Michael C

    2014-01-01

    Summary Handedness and brain asymmetry are widely regarded as unique to humans, and associated with complementary functions such as a left-brain specialization for language and logic and a right-brain specialization for creativity and intuition. In fact, asymmetries are widespread among animals, and support the gradual evolution of asymmetrical functions such as language and tool use. Handedness and brain asymmetry are inborn and under partial genetic control, although the gene or genes respo...

  20. FROM BRAIN DRAIN TO BRAIN NETWORKING

    OpenAIRE

    Irina BONCEA

    2015-01-01

    Scientific networking is the most accessible way a country can turn the brain drain into brain gain. Diaspora’s members offer valuable information, advice or financial support from the destination country, without being necessary to return. This article aims to investigate Romania’s potential of turning brain drain into brain networking, using evidence from the medical sector. The main factors influencing the collaboration with the country of origin are investigated. The co...

  1. Brain evolution by brain pathway duplication

    OpenAIRE

    Chakraborty, Mukta; Jarvis, Erich D

    2015-01-01

    Understanding the mechanisms of evolution of brain pathways for complex behaviours is still in its infancy. Making further advances requires a deeper understanding of brain homologies, novelties and analogies. It also requires an understanding of how adaptive genetic modifications lead to restructuring of the brain. Recent advances in genomic and molecular biology techniques applied to brain research have provided exciting insights into how complex behaviours are shaped by selection of novel ...

  2. Transparent Films from CO2 -Based Polyunsaturated Poly(ether carbonate)s: A Novel Synthesis Strategy and Fast Curing.

    Science.gov (United States)

    Subhani, Muhammad Afzal; Köhler, Burkhard; Gürtler, Christoph; Leitner, Walter; Müller, Thomas E

    2016-04-25

    Transparent films were prepared by cross-linking polyunsaturated poly(ether carbonate)s obtained by the multicomponent polymerization of CO2 , propylene oxide, maleic anhydride, and allyl glycidyl ether. Poly(ether carbonate)s with ABXBA multiblock structures were obtained by sequential addition of mixtures of propylene oxide/maleic anhydride and propylene oxide/allyl glycidyl ether during the polymerization. The simultaneous addition of both monomer mixtures provided poly(ether carbonate)s with AXA triblock structures. Both types of polyunsaturated poly(ether carbonate)s are characterized by diverse functional groups, that is, terminal hydroxy groups, maleate moieties along the polymer backbone, and pendant allyl groups that allow for versatile polymer chemistry. The combination of double bonds substituted with electron-acceptor and electron-donor groups enables particularly facile UV- or redox-initiated free-radical curing. The resulting materials are transparent and highly interesting for coating applications. PMID:27028458

  3. Glycol ethers--validation procedures for tube/pump and dosimeter monitoring methods.

    Science.gov (United States)

    Langhorst, M L

    1984-06-01

    Methods were developed and validated for personal monitoring of exposures to airborne glycol ethers, both short-term and long-term time-weighted-averages. Either a 600 mg charcoal tube or a 780 mg silica gel tube is recommended for monitoring nine glycol ethers, depending upon the humidity and other organic compounds to be monitored. The charcoal tube allows maximum sensitivity and is unaffected by high humidity conditions. Two-phase solvent desorption with CS2 and water allows aqueous phase recoveries of DOWANOL EM, PM, EE, DM, DPM, and TM glycol ethers. DOWANOL EB, DB and TPM glycol ethers are partitioned between the two layers, necessitating chromatographic analysis of both layers. The silica gel tube method can be used to monitor all nine glycol ethers tested, but is affected by high humidity conditions, resulting in significant breakthrough of the more volatile glycol ethers. The 3M organic vapor monitor can accurately and conveniently determine exposure concentrations for DOWANOL EM, EE, and PM glycol ethers, but sensitivities may be inadequate for sampling periods less than one hour. These methods were validated at levels down to 0.1 times the Dow internal exposure guidelines for those substances with Dow exposure guidelines and well above the current ACGIH and OSHA guidelines. This paper also illustrates validation procedures for tube/pump and dosimeter methods, allowing good definition of method accuracy and precision. Some screening experiments are described for diffusional dosimeters to check the most important parameters in a minimum of time. This methodology will allow assessment of human airborne exposures relative to the new toxicology data available on animals. PMID:6331145

  4. Effects of ethylene glycol ethers on diesel fuel properties and emissions in a diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Cuenca, F.; Gomez-Marin, M. [Compania Logistica de Hidrocarburos (CLH), Central Laboratory, Mendez Alvaro 44, 28045 Madrid (Spain); Folgueras-Diaz, M.B., E-mail: belenfd@uniovi.es [Department of Energy, University of Oviedo, Independencia 13, 33004 Oviedo (Spain)

    2011-08-15

    Highlights: {yields} Effect of ethylene glycol ethers on diesel fuel properties. {yields} Effect of ethylene glycol ethers on diesel engine specific consumption and emissions. {yields} Blends with {<=}4 wt.% of oxygen do not change substantially diesel fuel quality. {yields} Blends with 1 and 2.5 wt.% of oxygen reduce CO and HC emissions, but not smoke. - Abstract: The effect of ethylene glycol ethers on both the diesel fuel characteristics and the exhaust emissions (CO, NO{sub x}, smoke and hydrocarbons) from a diesel engine was studied. The ethers used were monoethylene glycol ethyl ether (EGEE), monoethylene glycol butyl ether (EGBE), diethylene glycol ethyl ether (DEGEE). The above effect was studied in two forms: first by determining the modification of base diesel fuel properties by using blends with oxygen concentration around 4 wt.%, and second by determining the emission reductions for blends with low oxygen content (1 wt.%) and with 2.5 wt.% of oxygen content. The addition of DEGEE enhances base diesel fuel cetane number, but EGEE and EGBE decrease it. For concentrations of {>=}4 wt.% of oxygen, EGEE and diesel fuel can show immiscibility problems at low temperatures ({<=}0 {sup o}C). Also, every oxygenated compound, according to its boiling point, modifies the distillation curve at low temperatures and the distillate percentage increases. These compounds have a positive effect on diesel fuel lubricity, and slightly decrease its viscosity. Blends with 1 and 2.5 wt.% oxygen concentrations were used in order to determine their influence on emissions at both full and medium loads and different engine speeds. Generally, all compounds help to reduce CO, and hydrocarbon emissions, but not smoke. The best results were obtained for blends with 2.5 wt.% of oxygen. At this concentration, the additive efficiency in decreasing order was EGEE > DEGEE > EGBE for CO emissions and DGEE > EGEE > EGBE for hydrocarbon emissions. For NO{sub x}, both its behaviour and the

  5. Effects of ethylene glycol ethers on diesel fuel properties and emissions in a diesel engine

    International Nuclear Information System (INIS)

    Highlights: → Effect of ethylene glycol ethers on diesel fuel properties. → Effect of ethylene glycol ethers on diesel engine specific consumption and emissions. → Blends with ≤4 wt.% of oxygen do not change substantially diesel fuel quality. → Blends with 1 and 2.5 wt.% of oxygen reduce CO and HC emissions, but not smoke. - Abstract: The effect of ethylene glycol ethers on both the diesel fuel characteristics and the exhaust emissions (CO, NOx, smoke and hydrocarbons) from a diesel engine was studied. The ethers used were monoethylene glycol ethyl ether (EGEE), monoethylene glycol butyl ether (EGBE), diethylene glycol ethyl ether (DEGEE). The above effect was studied in two forms: first by determining the modification of base diesel fuel properties by using blends with oxygen concentration around 4 wt.%, and second by determining the emission reductions for blends with low oxygen content (1 wt.%) and with 2.5 wt.% of oxygen content. The addition of DEGEE enhances base diesel fuel cetane number, but EGEE and EGBE decrease it. For concentrations of ≥4 wt.% of oxygen, EGEE and diesel fuel can show immiscibility problems at low temperatures (≤0 oC). Also, every oxygenated compound, according to its boiling point, modifies the distillation curve at low temperatures and the distillate percentage increases. These compounds have a positive effect on diesel fuel lubricity, and slightly decrease its viscosity. Blends with 1 and 2.5 wt.% oxygen concentrations were used in order to determine their influence on emissions at both full and medium loads and different engine speeds. Generally, all compounds help to reduce CO, and hydrocarbon emissions, but not smoke. The best results were obtained for blends with 2.5 wt.% of oxygen. At this concentration, the additive efficiency in decreasing order was EGEE > DEGEE > EGBE for CO emissions and DGEE > EGEE > EGBE for hydrocarbon emissions. For NOx, both its behaviour and the sequence are opposite to that of CO.

  6. Evaluation of hepatic biotransformation of polybrominated diphenyl ethers in the polar bear (Ursus maritimus).

    Science.gov (United States)

    Krieger, Lisa K; Szeitz, András; Bandiera, Stelvio M

    2016-03-01

    Polar bears are at the top of the Arctic marine food chain and are subject to exposure and bioaccumulation of environmental chemicals of concern such as polybrominated diphenyl ethers (PBDEs), which were widely used as flame retardants. The aim of the present study was to evaluate the in vitro oxidative metabolism of 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47) and 2,2',4,4',5-pentabrominated diphenyl ether (BDE-99) by polar bear liver microsomes. The identification and quantification of the hydroxy-brominated diphenyl ethers formed were assessed using an ultra-high performance liquid chromatography-tandem mass spectrometry-based method. Incubation of BDE-47 with archived individual liver microsomes, prepared from fifteen polar bears from northern Canada, produced a total of eleven hydroxylated metabolites, eight of which were identified using authentic standards. The major metabolites were 4'-hydroxy-2,2',4,5'-tetrabromodiphenyl ether and 5'-hydroxy-2,2',4,4'-tetrabromodiphenyl ether. Incubation of BDE-99 with polar bear liver microsomes produced a total of eleven hydroxylated metabolites, seven of which were identified using authentic standards. The major metabolites were 2,4,5-tribromophenol and 4-hydroxy-2,2',3,4',5-pentabromodiphenyl ether. Among the CYP specific antibodies tested, anti-rat CYP2B was found to be the most active in inhibiting the formation of hydroxylated metabolites of both BDE-47 and BDE-99, indicating that CYP2B was the major CYP enzyme involved in the oxidative biotransformation of these two congeners. Our study shows that polar bears are capable of forming multiple hydroxylated metabolites of BDE-47 and BDE-99 in vitro and demonstrates the role of CYP2B in the biotransformation and possibly in the toxicity of BDE-47 and BDE-99 in polar bears. PMID:26745384

  7. DIMETHYL ETHER (DME)-FUELED SHUTTLE BUS DEMONSTRATION PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Howard Glunt; Andre L. Boehman; Allen Homan; David Klinikowski

    2003-04-01

    The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In this project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. Their strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. The bulk of the efforts over the past year were focused on the conversion of the campus shuttle bus. This process, started in August 2001, took until April 2002 to complete. The process culminated in an event to celebrate the launching of the shuttle bus on DME-diesel operation on April 19, 2002. The design of the system on the shuttle bus was patterned after the system developed in the engine laboratory, but also was subjected to a rigorous failure modes effects analysis (FMEA, referred to by Air Products as a ''HAZOP'' analysis) with help from Dr. James Hansel of Air Products. The result of this FMEA was the addition of layers of redundancy and over-pressure protection to the system on the shuttle bus. The system became operational in February 2002. Preliminary emissions tests and basic operation of the shuttle bus took place at the Pennsylvania Transportation Institute's test track facility near the University Park airport. After modification and optimization of the system on

  8. A Theoretical Study on Reductive Debromination of Polybrominated Diphenyl Ethers

    Directory of Open Access Journals (Sweden)

    Xian-Fei Huang

    2012-07-01

    Full Text Available Recent progress has been made in the reductive debromination of polybrominated diphenyl ethers (PBDEs by nanoscale zero-valent iron (nZVI. To better understand the mechanism of this reaction, seven selected BDE congeners and their anions were investigated at the density functional theory (DFT level using four different methods, including B3LYP/6-31G(d, B3LYP/6-31+G(d, B3LYP/6-31G(d,p and B3LYP/6-311G(d,p. The cleaved C–Br bonds observed in the equilibrium structures of anionic PBDEs were adopted as the probe of the susceptible debromination position of PBDEs in the presence of nZVI, and the proposed major reaction pathways based on our calculations can satisfactorily conform to the reported experimental results. The debromination preference is theoretically evaluated as meta-Br > ortho-Br > para-Br. In addition, both the calculated frontier orbital energies and adiabatic electronic affinities were found to be highly related to their experimental reductive debromination rate constants. The highest linear regression coefficient was observed in the case using the energy of lowest unoccupied molecular orbital as the molecular descriptor obtained from B3LYP/6-31G(d (R2 = 0.961, n = 7 or B3LYP/6-31G(d,p (R2 = 0.961, n = 7. The results clearly showed the evidence of an electron transfer mechanism associated with this reductive debromination reaction.

  9. Synthesis and physicochemical properties of polyhydroxylated diphenyl ethers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fu; Zhang, Xuesheng; Qu, Ruijuan; Shi, Jiaqi; Wang, Zunyao, E-mail: wangzun315cn@163.com

    2013-09-20

    Highlights: • The experimental pK{sub a1} values of five synthesized PHODEs were determined. • The hydrogen bonds existed in PHODEs were investigated. • There exist close relationships between the thermodynamic properties and N{sub PHOS}. • The relative stability order of PHODE congeners was theoretically proposed. - Abstract: Five polyhydroxylated diphenyl ethers (PHODEs) were synthesized. The first ionization constants (pK{sub a1}) of the synthesized compounds and seven phenolic compounds were determined using potentiometric titration experiments, together with the software ACD/Labs pK{sub a} DB program (version 6.0). The compared results showed that the software could be used to predict the pK{sub a1} of all 209 PHODEs. The thermodynamic properties of 209 PHODEs were calculated using density functional theory (DFT) at the B3LYP/6-311G** level with Gaussian 09 program. The standard enthalpy of formation (Δ{sub f}H{sup θ}) and the standard Gibbs energy of formation (Δ{sub f}G{sup θ}) were obtained. Two types of hydrogen bond were found to exist in the PHODEs’ molecules. The intramolecular hydrogen bond energies were discussed. The relative stability of PHODEs isomers was proposed theoretically with the relative standard Gibbs energy of formation (Δ{sub f}G{sub R}{sup θ}). The relationships of S{sup θ}, Δ{sub f}H{sup θ} and Δ{sub f}G{sup θ} to the number and position of the hydroxyl substitution (N{sub PHOS}) were studied.

  10. Oral bioavailability of the ether lipid plasmalogen precursor, PPI-1011, in the rabbit: a new therapeutic strategy for Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Wood Paul L

    2011-12-01

    Full Text Available Abstract Introduction Docosahexaenoic acid (DHA and DHA-containing ethanolamine plasmalogens (PlsEtn are decreased in the brain, liver and the circulation in Alzheimer's disease. Decreased supply of plasmalogen precursors to the brain by the liver, as a result of peroxisomal deficits is a process that probably starts early in the AD disease process. To overcome this metabolic compromise, we have designed an orally bioavailable DHA-containing ether lipid precursor of plasmalogens. PPI-1011 is an alkyl-diacyl plasmalogen precursor with palmitic acid at sn-1, DHA at sn-2 and lipoic acid at sn-3. This study outlines the oral pharmacokinetics of this precursor and its conversion to PlsEtn and phosphatidylethanolamines (PtdEtn. Methods Rabbits were dosed orally with PPI-1011 in hard gelatin capsules for time-course and dose response studies. Incorporation into PlsEtn and PtdEtn was monitored by LC-MS/MS. Metabolism of released lipoic acid was monitored by GC-MS. To monitor the metabolic fate of different components of PPI-1011, we labeled the sn-1 palmitic acid, sn-2 DHA and glycerol backbone with13C and monitored their metabolic fates by LC-MS/MS. Results PPI-1011 was not detected in plasma suggesting rapid release of sn-3 lipoic acid via gut lipases. This conclusion was supported by peak levels of lipoic acid metabolites in the plasma 3 hours after dosing. While PPI-1011 did not gain access to the plasma, it increased circulating levels of DHA-containing PlsEtn and PtdEtn. Labeling experiments demonstrated that the PtdEtn increases resulted from increased availability of DHA released via remodeling at sn-2 of phospholipids derived from PPI-1011. This release of DHA peaked at 6 hrs while increases in phospholipids peaked at 12 hr. Increases in circulating PlsEtn were more complex. Labeling experiments demonstrated that increases in the target PlsEtn, 16:0/22:6, consisted of 2 pools. In one pool, the intact precursor received a sn-3

  11. Defects in myelination, paranode organization and Purkinje cell innervation in the ether lipid-deficient mouse cerebellum.

    Science.gov (United States)

    Teigler, Andre; Komljenovic, Dorde; Draguhn, Andreas; Gorgas, Karin; Just, Wilhelm W

    2009-06-01

    Ether lipids (ELs), particularly plasmalogens, are essential constituents of the mammalian central nervous system. The physiological role of ELs, in vivo, however is still enigmatic. In the present study, we characterized a mouse model carrying a targeted deletion of the peroxisomal dihydroxyacetonephosphate acyltransferase gene that results in the complete lack of ELs. Investigating the cerebellum of these mice, we observed: (i) defects in foliation patterning and delay in precursor granule cell migration, (ii) defects in myelination and concomitant reduction in the level of myelin basic protein, (iii) disturbances in paranode organization by extending the Caspr distribution and disrupting axo-glial septate-like junctions, (iv) impaired innervation of Purkinje cells by both parallel fibers and climbing fibers and (v) formation of axon swellings by the accumulation of inositol-tris-phosphate receptor 1 containing smooth ER-like tubuli. Functionally, conduction velocity of myelinated axons in the corpus callosum was significantly reduced. Most of these phenotypes were already apparent at P20 but still persisted in 1-year-old animals. In summary, these data show that EL deficiency results in severe developmental and lasting structural alterations at the cellular and network level of the cerebellum, and reveal an important role of ELs for proper brain function. Common molecular mechanisms that may underlie these phenotypes are discussed. PMID:19270340

  12. Polychlorinated biphenyls, organochlorinated pesticides, and polybrominated diphenyl ethers in the cerebral cortex of wild river otters (Lontra canadensis)

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Niladri [National Wildlife Research Center, Canadian Wildlife Service, Environment Canada, Ottawa, Ontario, K1A 0H3 (Canada)]. E-mail: nbasu@uottawa.ca; Scheuhammer, Anton M. [National Wildlife Research Center, Canadian Wildlife Service, Environment Canada, Ottawa, Ontario, K1A 0H3 (Canada); O' Brien, Mike [Furbearers and Upland Game, Nova Scotia Department of Natural Resources, Kentville, Nova Scotia, B4N 4E5 (Canada)

    2007-09-15

    We measured the levels of ortho-substituted polychlorinated biphenyls (PCB), organochlorinated pesticides (OCP), and polybrominated diphenyl ethers (PBDE) in the cerebral cortex of river otters (Lontra canadensis) trapped from Ontario and Nova Scotia between 2002 and 2004. The mean concentration of total PCBs was 70.9 {+-} 12.1 ng/g l.w., and congeners 153, 180 and 138 accounted for nearly 60% of the sum. The mean concentration of total OCPs was 21.2 {+-} 3.7 ng/g l.w., and hexachlorobenzene (32.6% of total) and DDE (28.1%) accounted for the majority. The mean concentration of total PBDEs was 3.2 {+-} 0.6 ng/g l.w., and congeners 99 (44.9%), 153 (30.5%), and 100 (24.7%) were measured at the indicated percentages. There was no relationship between these residue data and concentrations of brain mercury or neurochemical receptors and enzymes as determined in earlier studies on these same animals. - River otters accumulated PCBs, OCPs, and PBDEs, but at levels below thresholds for neurotoxic effects.

  13. Polychlorinated biphenyls, organochlorinated pesticides, and polybrominated diphenyl ethers in the cerebral cortex of wild river otters (Lontra canadensis)

    International Nuclear Information System (INIS)

    We measured the levels of ortho-substituted polychlorinated biphenyls (PCB), organochlorinated pesticides (OCP), and polybrominated diphenyl ethers (PBDE) in the cerebral cortex of river otters (Lontra canadensis) trapped from Ontario and Nova Scotia between 2002 and 2004. The mean concentration of total PCBs was 70.9 ± 12.1 ng/g l.w., and congeners 153, 180 and 138 accounted for nearly 60% of the sum. The mean concentration of total OCPs was 21.2 ± 3.7 ng/g l.w., and hexachlorobenzene (32.6% of total) and DDE (28.1%) accounted for the majority. The mean concentration of total PBDEs was 3.2 ± 0.6 ng/g l.w., and congeners 99 (44.9%), 153 (30.5%), and 100 (24.7%) were measured at the indicated percentages. There was no relationship between these residue data and concentrations of brain mercury or neurochemical receptors and enzymes as determined in earlier studies on these same animals. - River otters accumulated PCBs, OCPs, and PBDEs, but at levels below thresholds for neurotoxic effects

  14. Congenital malformation and maternal occupational exposure to glycol ethers. Occupational Exposure and Congenital Malformations Working Group.

    Science.gov (United States)

    Cordier, S; Bergeret, A; Goujard, J; Ha, M C; Aymé, S; Bianchi, F; Calzolari, E; De Walle, H E; Knill-Jones, R; Candela, S; Dale, I; Dananché, B; de Vigan, C; Fevotte, J; Kiel, G; Mandereau, L

    1997-07-01

    Glycol ethers are found in a wide range of domestic and industrial products, many of which are used in women's work environments. Motivated by concern about their potential reproductive toxicity, we have evaluated the risk of congenital malformations related to glycol ether exposure during pregnancy as part of a multicenter case-control study, conducted in six regions in Europe. The study comprised 984 cases of major congenital malformations and 1,134 controls matched for place and date of birth. Interviews of the mothers provided information about occupation during pregnancy, sociodemographic variables, and other potential risk factors (medical history, tobacco, alcohol, drugs). A chemist specializing in glycol ethers evaluated exposure during pregnancy, using the job description given by the mother, without knowledge of case or control status. We classified malformations into 22 subgroups. The overall odds ratio (OR) of congenital malformation associated with glycol ether exposure was 1.44 [95% confidence interval (CI) = 1.10-1.90], after adjustment for several potential confounders. The association with exposure to glycol ethers appeared particularly strong in three subgroups: neural tube defects (OR = 1.94; 95% CI = 1.16-3.24), multiple anomalies (OR = 2.00; 95% CI = 1.24-3.23), and cleft lip (OR = 2.03; 95% CI = 1.11-3.73). In this last subgroup, risk, especially of an isolated defect, tended to increase with level of exposure. PMID:9209847

  15. Synthesis and intrinsic blue fluorescence study of hyperbranched poly(ester-amide-ether)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A series of hyperbranched poly(ester-amide-ether)s (H-PEAEs) were synthesized via the A2+CB3 approach by the self-transesterification of ethyl ester-amide-ethers end-capped with three hydroxyl groups and ethyl ester group at two terminals.The molecular structures were characterized with 1H NMR and FT-IR spectroscopy.The number average molecular weights were estimated by GPC analysis to possess bimodal wide distribution from 1.57 to 2.09.The strong inherent blue fluorescence was observed at 330 nm for excitation and 390 nm for emission.Moreover,the emission intensity and fluorescence quantum yield increased along with the incorporated ether chain length,as well as almost linearly with the H-PEAE concentration in an aqueous solution.For comparing the fluorescence performance,the linear poly(ester-amide-ether) (L-PEAE) and hyperbranched poly(ester-amide) (H-PEA) were synthesized.The results showed that the coexistence of ether bond and carboxyl group in the molecular chain was essential for generating the strong fluorescence.However,the compact backbone of H-PEAE would be propitious to the enhancement of fluorescence properties.

  16. Ether and siloxane functionalized ionic liquids and their mixtures as electrolyte for lithium-ion batteries.

    Science.gov (United States)

    Chavan, Santosh N; Tiwari, Aarti; Nagaiah, Tharamani C; Mandal, Debaprasad

    2016-06-28

    The present study deals with an investigation of two novel imidazolium ionic liquids bearing ether-ether (1O2O2-Im-2O1) or ether-siloxane (1O2O2-Im-1SiOSi) functionalities with TFSI anion and their mixtures with propylene carbonate as electrolytes in lithium-ion batteries. The electrochemical stability and conductivity of these novel ILs were analyzed by electrochemical studies, such as cyclic voltammetry, linear sweep voltammetry and impedance measurements. The applicability of these ILs as electrolytes in Li-ion batteries was studied in the presence of a high concentration of LiTFSI (1 mol kg(-1) electrolyte) and the ether-ether IL was shown to possess a high electrochemical stability window (ESW) of 5.9 V and good conductivity of 2.2 mS cm(-1). The electrochemical stability and conductivity were further complimented by self-diffusion of different ions using pulsed gradient spin-echo (PGSE) NMR, viscosity and thermal properties like TGA and DSC analysis. More importantly, we explored the effect of temperature on the electrochemical stability and conductivity of these ILs by electrochemical impedance spectroscopy. PMID:27004982

  17. 13C solution NMR spectra of poly(ether)urethanes. Technical memorandum

    International Nuclear Information System (INIS)

    The 13C solution nuclear magnetic resonance (NMR) spectra of the 15 poly(ether)urethanes are presented. The poly(urethane)s were prepared using one of two diisocyanates, either methylene diphenyl diisocyanate (MDI) or hexamethylene diisocyanate (HDI), one of five poly(ether glycol)s, poly(tetramethylene ether glycol) of molecular weight 650, 1000, or 1400, or poly(ethylene glycol) of molecular weight 600 or 1000, and one of three chain extenders, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, or diethylene glycol. These polymers were prepared as part of a modelling study to determine if Group Contribution Theory and Group Interaction Modelling could be used to predict dynamic mechanical properties of poly(ether)urethanes on the basis of the structural fragments in the polymers. The chemical shifts of the unique carbons in each of the poly(urethane)s are assigned. They can be used to unambiguously identify the diisocyanate/diol/poly(ether glycol) used to prepare the various polyurethanes. For some compounds the spectra show resonances for terminal hydroxyl substituted carbons. These could provide a method, under the right experimental conditions, to compare molecular weights of batches of the same polymer. (author)

  18. Metabolism of nitrodiphenyl ether herbicides by dioxin-degrading bacterium Sphingomonas wittichii RW1.

    Science.gov (United States)

    Keum, Young Soo; Lee, Young Ju; Kim, Jeong-Han

    2008-10-01

    Nitrodiphenyl ether herbicides, including chlomethoxyfen, nitrofen, and oxyfluorfen are potent herbicides. Some metabolites and parent compounds are considered as possible mutagens and endocrine disruptors. Both properties pose serious hygienic and environmental risks. Sphingomonas wittichii RW1 is a well-known degrader of polychlorinated dibenzo- p-dioxins, dibenzofurans, and diphenyl ethers. However, no detailed research of its metabolic activity has been performed against pesticides with a diphenyl ether scaffold. In this study, we report S. wittichii RW1 as a very potent diphenyl ether herbicide-metabolizing bacterium with broad substrate specificity. The structures of metabolites were determined by instrumental analysis and synthetic standards. Most pesticides were rapidly removed from the culture medium in the order of nitrofen > oxyfluorfen > chlomethoxyfen. In general, herbicides were degraded through the initial reduction and N-acetylation of nitro groups, followed by ether bond cleavage. Relatively low concentrations of phenolic and catecholic metabolites throughout the study suggested that these metabolites were rapidly metabolized and incorporated into primary metabolism. These results indicate that strain RW1 has very versatile metabolic activities over a wide range of environmental contaminants. PMID:18778066

  19. Development of the aza-crown ether metal complexes as artificial hydrolase.

    Science.gov (United States)

    Yu, Lan; Li, Fang-zhen; Wu, Jiao-yi; Xie, Jia-qing; Li, Shuo

    2016-01-01

    Hydrolases play a crucial role in the biochemical process, which can catalyze the hydrolysis of various compounds like carboxylic esters, phosphoesters, amides, nucleic acids, peptides, and so on. The design of artificial hydrolases has attracted extensive attention due to their scientific significance and potential applications in the field of gene medicine and molecular biology. Numerous macrocyclic metal complexes have been used as artificial hydrolase in the catalytic hydrolysis of the organic substrate. Aza-crown ether for this comment is a special class of the macrocyclic ligand containing both the nitrogen atoms and oxygen atoms in the ring. The studies showed that the aza-crown complexes exhibited high activity of hydrolytic enzyme. However, the aza-crown ether metal complex as artificial hydrolase is still very limited because of its difficulty in synthesis. This review summarizes the development of the aza-crown ether metal complexes as the artificial hydrolase, including the synthesis and catalysis of the transition metal complexes and lanthanide metal complexes of aza-crown ethers. The purpose of this review is to highlight: (1) the relationship between the structure and hydrolytic activity of synthetic hydrolase; (2) the synergistic effect of metal sites and ligands in the course of organic compound hydrolysis; and (3) the design strategies of the aza-crown ethers as hydrolase. PMID:26460062

  20. SECONDARY BRAIN INJURY

    OpenAIRE

    Ida Ayu Basmatika

    2013-01-01

    Secondary brain injury is a condision that occurs at some times after the primary impact and can be largely prevented and treated. Most brain injury ends with deadly consequences which is caused by secondary damage to the brain. Traumatic brain injured still represents the leading cause of morbidity and mortality in individuals under the age of 45 years in the world. The classification of secondary brain injured is divided into extracranial and intracranial causes. The cause of extracranial s...

  1. Brain Drain Controversy

    OpenAIRE

    Borta, Oxana

    2007-01-01

    This thesis focuses on the widely acknowledged so-called brain drain controversy. More concretely on developments in the traditional brain drain literature towards a new shift, claiming the brain gain effect, as an alternative to the brain drain effect, that emigration may bring to a source country. The research investigates not only the obvious direct loss effects – the so called brain drain – but also the possibility of more subtle indirect beneficial effects.

  2. Brain evolution by brain pathway duplication.

    Science.gov (United States)

    Chakraborty, Mukta; Jarvis, Erich D

    2015-12-19

    Understanding the mechanisms of evolution of brain pathways for complex behaviours is still in its infancy. Making further advances requires a deeper understanding of brain homologies, novelties and analogies. It also requires an understanding of how adaptive genetic modifications lead to restructuring of the brain. Recent advances in genomic and molecular biology techniques applied to brain research have provided exciting insights into how complex behaviours are shaped by selection of novel brain pathways and functions of the nervous system. Here, we review and further develop some insights to a new hypothesis on one mechanism that may contribute to nervous system evolution, in particular by brain pathway duplication. Like gene duplication, we propose that whole brain pathways can duplicate and the duplicated pathway diverge to take on new functions. We suggest that one mechanism of brain pathway duplication could be through gene duplication, although other mechanisms are possible. We focus on brain pathways for vocal learning and spoken language in song-learning birds and humans as example systems. This view presents a new framework for future research in our understanding of brain evolution and novel behavioural traits. PMID:26554045

  3. Determination of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether in human urine by HS-SPME gas chromatography/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Scibetta, Licia [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy); Campo, Laura [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy); Mercadante, Rosa [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy); Foa, Vito [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy); Fustinoni, Silvia [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy)]. E-mail: silvia.fustinoni@unimi.it

    2007-01-02

    Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are oxygenated compounds added to gasoline to enhance octane rating and to improve combustion. They may be found as pollutants of living and working environments. In this work a robotized method for the quantification of low level MTBE, ETBE and TAME in human urine was developed and validated. The analytes were sampled in the headspace of urine by SPME in the presence of MTBE-d12 as internal standard. Different fibers were compared for their linearity and extraction efficiency: carboxen/polydimethylsiloxane, polydimethylsiloxane/divinylbenzene, and polydimethylsiloxane. The first, although highly efficient, was discarded due to deviation of linearity for competitive displacement, and the polydimethylsiloxane/divinylbenzene fiber was chosen instead. The analysis was performed by GC/MS operating in the electron impact mode. The method is very specific, with range of linearity 30-4600 ng L{sup -1}, within- and between-run precision, as coefficient of variation, <22 and <16%, accuracy within 20% the theoretical level, and limit of detection of 6 ng L{sup -1} for all the analytes. The influence of the matrix on the quantification of these ethers was evaluated analysing the specimens of seven traffic policemen exposed to autovehicular emissions: using the calibration curve and the method of standard additions comparable levels of MTBE (68-528 ng L{sup -1}), ETBE (<6 ng L{sup -1}), and TAME (<6 ng L{sup -1}) were obtained.

  4. Interações químico-fisiolóficas entre acidificantes, probióticos, enzimas e lisofosfolipídios na digestão de leitões Chemical and philosophic interactions of acidifiers, probiotics, enzymes and lysophospholipids in the piglest digestion

    Directory of Open Access Journals (Sweden)

    Arnaldo da Silva Junior

    2009-07-01

    imbalance in the microbial intestinal microflora, opening doors to diarrhea and other intestinal diseases, or even facilitating systemic problems of animal health. These problems become even more critical in the current scenario of increased risk with the progressive restriction of the use of antibiotic growth promoters around the world. Young animals, as piglets, are more susceptible to these problems due to the incomplete state of development of these animals, with less capacity and digestive enzymes, associated with an immature and less efficient immune system. The intestine of these animals is still in colonization process, so there is higher susceptibility to microflora imbalance and enteric problems. Several new technologies have been developed and implemented to address these challenges, such as Enzymes, Organic Acids, Probiotics and Lysophospholipids. A discussion will be presented showing how the supplementation of diets with these technologies have the potential to allow the formulation of lower nutrient density diets, generating less environmental pollution, and promoting better livestock performance and animal health. There are several evidences that point to a potentially synergistic activity of these technologies in the gastrointestinal tract increasing the digestibility of nutrients and promoting a positive balance of the resident intestinal microflora.

  5. α-linolenic omega-3 fatty acid for stroke protection: from brain preconditioning paradigm to nutrition

    Directory of Open Access Journals (Sweden)

    Blondeau Nicolas

    2011-09-01

    Full Text Available Stroke is the third leading cause of death, due to its high incidence, the severity of the insult, and lack of treatment options. The only therapeutic is restoration of cerebral blood flow achieved by recombinant tissue plasminogen activator treatment, but only approximately 5% of patients receive it. In addition, therapeutics aimed at achieving neuroprotection by blocking the ischemic cascade, as identified in numerous preclinical studies, failed in clinical trials. This failure in translation from experimental models to clinical trials led to a re-evaluation of properties which would constitute the ‘‘best-in class’’ therapeutics to be used against stroke. Given that neuroprotection appears ineffective per se, an emerging direction is to identify therapies, probably combinatorial in nature, which protect the whole neurovascular unit and target timedependent neurotoxic mechanisms. Molecules that activate complex cellular signaling cascades that render the brain resistant to subsequent ischemia, known as preconditioners, offer a novel perspective in stroke protection. Preconditioning elicits complex endogenous neuroprotective responses that act by pleiotropic mechanisms to block death pathways, promote survival pathways and increase resistance. In addition to chemical preconditioners, natural/endogenous compounds such as adenosine, glutamate, lysophospholipids, and omega-3 polyunsaturated fatty acids have been demonstrated to be excellent preconditioners. Consequently, a major new concept in preconditioning to combat stroke is introduced, which is preconditioning achieved through supplementation of an essential item in diet or as a nutraceutical. Several epidemiologic studies suggested a beneficial effect of a seafood/omega-3-enriched diet in cerebral diseases, but the omega-3-induced protective mechanisms are still poorly identified. This review highlights how α-linolenic acid (ALA, the omega-3 polyunsaturated fatty acid precursor

  6. Functionalization of oxidized single-walled carbon nanotubes with 4-benzo-9-crown-3 ether

    Indian Academy of Sciences (India)

    Ardeshir Khazaei; Maryam Kiani Borazjani; Khadijeh Mansouri Moradian

    2012-09-01

    Functionalization of oxidized single-walled carbon nanotubes (SWCNTs) by a zwitterionic interaction (COO−NH$^{+}_{3}$) between protonated amine on crown ether and an oxyanion from a carboxylic acid group on SWCNT has been described. This ionic interaction has led to a considerable increase in the solubility of SWCNTs in both organic and aqueous solvents such as ethanol, dimethyl sulphoxide, dimethylformamide, and H2O. The highest solubility was attained in DMF and DMSO. The ionic bonded 4-benzo-9-crown-3 ether allowed the hosting of Li+. The ionic bond of crown ether (4-(benzo-9-crown-3)) to SWCNT was identified and confirmed by infrared spectroscopy, transmission electron-microscopy, atomic force microscopy and thermogravimetric analysis methods.

  7. Arginine-responsive terbium luminescent hybrid sensors triggered by two crown ether carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Lasheng [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Tang, Ke; Ding, Xiaoping [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Zhou, Zhan; Xiao, Rui [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

    2013-12-01

    Crown ether carboxylic acids constitute main building blocks for the synthesis of terbium containing covalent cross-linked luminescent materials. Both the complexes and the hybrid nanomaterials could exhibit remarkable green emissions in pure water. More importantly, they were found to have a profound effect on the luminescence responses to arginine compared with glutamic acid, histidine, tryptophan, threonine, tyrosine and phenylalanine in aqueous environment. The present study provided the possibility of using a host–guest mechanism as a way of signal transduction based on lanthanide supramolecular hybrid materials. - Highlights: • Crown ether carboxylic acids were found to sensitize terbium ions among a group of ethers. • The complexes and silica hybrid materials were both prepared and characterized. • They could exhibit remarkable green emissions in pure water.

  8. Arginine-responsive terbium luminescent hybrid sensors triggered by two crown ether carboxylic acids

    International Nuclear Information System (INIS)

    Crown ether carboxylic acids constitute main building blocks for the synthesis of terbium containing covalent cross-linked luminescent materials. Both the complexes and the hybrid nanomaterials could exhibit remarkable green emissions in pure water. More importantly, they were found to have a profound effect on the luminescence responses to arginine compared with glutamic acid, histidine, tryptophan, threonine, tyrosine and phenylalanine in aqueous environment. The present study provided the possibility of using a host–guest mechanism as a way of signal transduction based on lanthanide supramolecular hybrid materials. - Highlights: • Crown ether carboxylic acids were found to sensitize terbium ions among a group of ethers. • The complexes and silica hybrid materials were both prepared and characterized. • They could exhibit remarkable green emissions in pure water

  9. Triclosan and Hydroxylated Polybrominated Diphenyl Ethers in Lake and Esturaine Sediments

    Science.gov (United States)

    Arnold, W. A.; Kerrigan, J. F.; McNeill, K.; Erickson, P. R.; Grandbois, M.

    2014-12-01

    Halogenated diphenyl ethers are a class of emerging contaminants that includes the antibacterial compound triclosan and the flame retardant polybrominated diphenyl ethers (PBDEs). Both triclosan and hydroxylated polybrominated diphenyl ethers (OH-BDEs) are known to form dioxins when exposed to sunlight in aqueous solution. Thus, it is important to understand the sources and presence of these compounds in the environment, especially because OH-BDEs are breakdown products of PBDEs and also naturally produced compounds. In this work, the levels of OH-BDEs were determined in lake sediments from Minnesota and esturaine sediments from San Francisco Bay. Both surface sediments over a broad spatial area and sediment cores were collected and analyzed. Triclosan was used as a marker of wastewater as a source of the targeted emerging contaminants. The relationship between triclosan and OH-BDE levels provides insight into the importance of natural and anthropogenic influences on the levels of OH-BDEs.

  10. Differential Self-Assembly of Novel Redox Crown Ethers

    Science.gov (United States)

    Merithew, Andrew William

    Retinal prosthesis relies on the stimulation of living nerve tissue behind the rods and cones of the eye. The current state of the art relies on electrodes controlled by cameras which directly stimulate the nerve tissue to elicit a response to an image. These types of retinal implants have allowed for short-term crude vision in patients but have had limited long term success due to external battery packs and electroplating of the implanted electrodes. Ionic stimulation is one of the principle mechanisms that sensory neurons utilize in the generation of an action potential. In a complex transduction pathway, ionic gradients are constantly altered inside the neuron by voltage sensors or mechanically controlled gates embedded in the neuronal cell membrane; responsible for the open and close state of these ion channels. It has been demonstrated that local concentration increases of K + by direct injection proximal to the nerve can elicit nerve firing at a concentration of 15-20 mM (3-4X normal concentration) increase in K + concentration. As part of a larger concept of integrating biotechnology with nanofabrication, the materials for the development of potassium selective sequestration/storage and delivery were developed in the form of a redox-gated K+ selective crown ether. The structure of the anthraquinone-based crown was deduced by computational simulation and stoichiometry of the complex confirmed by mass spec. along with 2D diffusion NMR techniques. In this instance, the stoichiometry could be controlled by the addition of different salts to give a 1:1 complex with large, aromatic anions and a 2:1 complex with smaller anions such as triflate. The synthesis of the molecule was optimized by computational modeling and simulations of transport through an artificial membrane. The selectivity of the architecture developed was specific for K+ over Na+, the other major ionic species present in the blood. The mechanism influencing the self-assembly of this class of

  11. APPLICATION OF PHOTOCATALYTIC PROCESS FOR REMOVAL OF METHYL TERT-BUTYL ETHER FROM HIGHLYCONTAMINATED WATER

    Directory of Open Access Journals (Sweden)

    A. Mesdaghinia

    2007-09-01

    Full Text Available The oxygenate methyl tert-butyl ether is added to gasoline to increase the octane level and to reduce carbon monoxide and hydrocarbon emissions by vehicles. The high mobility, water solubility, and resistance to natural attenuation associated with methyl tert-butyl ether may result in contamination of ground and surface waters. In this research the degradation of aqueous methyl tert-butyl ether at relatively high concentrations was investigated by UV-vis/TiO2/H2O2 photocatalytic process. The effect of important operational parameters such as pH, amount of H2O2, catalyst loading, and irradiation time were also studied. Concentrations of methyl tert-butyl ether and intermediates such as tert-butyl formate and tert-butyl alcohol were measured over a 180 min period using a gas chromatograph equipped with flame ionization detector and combined with headspace sampler. Results showed that the time required for complete degradation increased from 30 to 180min, when the initial concentration was increased from 10 to 500mg/L. The first order rate constant for degradation of methyl tert-butyl ether from the hydroxyl radical was estimated to be 0.177 to 0.022 1/min as the concentration increased from 10 to 500mg/L. Study on the overall mineralization monitored by total organic carbon (TOC analysis showed that in the initial concentration of 100mg/L methyl tert-butyl ether, complete mineralization was obtained after 110min under UV-vis/TiO2/H2O2 photocatalytic process.

  12. FROM BRAIN DRAIN TO BRAIN NETWORKING

    Directory of Open Access Journals (Sweden)

    Irina BONCEA

    2015-06-01

    Full Text Available Scientific networking is the most accessible way a country can turn the brain drain into brain gain. Diaspora’s members offer valuable information, advice or financial support from the destination country, without being necessary to return. This article aims to investigate Romania’s potential of turning brain drain into brain networking, using evidence from the medical sector. The main factors influencing the collaboration with the country of origin are investigated. The conclusions suggest that Romania could benefit from the diaspora option, through an active implication at institutional level and the implementation of a strategy in this area.

  13. Expression and induction of secretory phospholipase A2 group IB in brain

    DEFF Research Database (Denmark)

    Kolko, Miriam; Christoffersen, Nanna R; Varoqui, Hélène;

    2005-01-01

    Secretory phospholipases A2 (sPLA2) form a diverse family of enzymes involved in physiologic and pathologic processes. Common among all sPLA2 is the ability to cleave acyl groups of phospholipids at C2 of the glycerol backbone, thereby releasing fatty acid and a lysophospholipid. Several sPLA2 ha...

  14. 76 FR 36349 - Diethylene Glycol MonoEthyl Ether (DEGEE); Exemption From the Requirement of a Tolerance

    Science.gov (United States)

    2011-06-22

    ... AGENCY 40 CFR Part 180 Diethylene Glycol MonoEthyl Ether (DEGEE); Exemption From the Requirement of a... establishes an exemption from the requirement of a tolerance for residues of Diethylene Glycol MonoEthyl Ether...) 305-5805. II. Petition for Exemption In the Federal Register of July 9, 2008 (73 FR 39291)...

  15. Lewis base activation of Lewis acids. Catalytic enantioselective addition of silyl enol ethers of achiral methyl ketones to aldehydes.

    Science.gov (United States)

    Denmark, Scott E; Heemstra, John R

    2003-06-26

    A highly enantioselective addition of silyl enol ethers derived from simple methyl ketones is described. The catalyst system of silicon tetrachloride activated by a chiral bisphosphoramide (R,R)-7 effectively promotes the addition of a variety of unsubstituted silyl enol ethers to aromatic, olefinic, and heteroaromatic aldehydes in excellent yield. [reaction: see text] PMID:12816434

  16. 40 CFR 63.63 - Deletion of ethylene glycol monobutyl ether from the list of hazardous air pollutants.

    Science.gov (United States)

    2010-07-01

    ... ether from the list of hazardous air pollutants. 63.63 Section 63.63 Protection of Environment... AIR POLLUTANTS FOR SOURCE CATEGORIES List of Hazardous Air Pollutants, Petitions Process, Lesser... list of hazardous air pollutants. The substance ethylene glycol monobutyl ether...

  17. Gold( i )-catalysed dehydrative formation of ethers from benzylic alcohols and phenols

    KAUST Repository

    Veenboer, Richard M. P.

    2015-01-01

    © The Royal Society of Chemistry 2015. We report the cross-dehydrative reaction of two alcohols to form unsymmetrical ethers using NHC-gold(i) complexes (NHC = N-heterocyclic carbene). Our progress in developing this reaction into a straightforward procedure is discussed in detail. The optimised methodology proceeds under mild reaction conditions and produces water as the sole by-product. The synthetic utility of this environmentally benign methodology is exemplified by the formation of a range of new ethers from readily available phenols bearing electron withdrawing substituents and secondary benzylic alcohols with various substituents. Finally, we present experimental results to account for the chemoselectivity obtained in these reactions.

  18. Evaluation of various Crown ethers for the supercritical fluid extraction of uranium from nitric acid medium

    International Nuclear Information System (INIS)

    Various crowns have been evaluated for supercritical fluid extraction of uranium from nitric acid medium employing HPFOA as counter ion. Uranium extraction efficiency was found to be influenced by cavity size of crown ether and nature of substituents. Complexation tendency of UO22+ increases with increasing cavity size of crown ether. Electron withdrawing substituents decreased the extraction efficiency which could be attributed to decrease in the basicity of four oxygen atoms and hence their bonding ability. Whereas electron donating substituents increased the efficiency due to increases in basicity of oxygen atoms and hence in increase in bonding ability. (author)

  19. Alkyl aryl ethers in lignite solubilization 1. Study of the process

    Energy Technology Data Exchange (ETDEWEB)

    Mastral, A.M.; Cebolla, V.L.; Gavilan, J.M.

    1984-10-01

    The chemistry of solubilization of a lignite has been investigated with anisole, 3-methyl anisole and 1,3dimethoxybenzene catalysed by SbCl/sub 3/, ZnCl/sub 2/, AlCl/sub 3/ and BF/sub 3/ as boron trifluoride etherate, at atmospheric pressure and temperatures <220/sup 0/C. 60% of lignite was solubilized in a toluene-ethanol azeotropic mixture. During the process, the solvent is incorporated as an alkylated substratum. The yield increased with activity of the aromatic ether ring and catalyst acidity.

  20. Alkyl aryl ethers in lignite solubilization. 1. Study of the process

    Energy Technology Data Exchange (ETDEWEB)

    Mastral, A.M.; Cebolla, V.L.; Gavilan, J.M.

    1984-10-01

    The chemistry of solubilization of a lignite has been investigated with anisole, 3-methyl anisole and 13-dimethoxybenzene catalysed by SbCl/sub 3/, ZnCl/sub 2/, AlCl/sub 3/ and BF/sub 3/ as boron trifluoride etherate, at atmospheric pressure and temperatures <220 C. 60% of lignite was solubilized in a toluene-ethanol azeotropic mixture. During the process, the solvent is incorporated as an alkylated substratum. The yield increased with activity of the aromatic ether ring and catalyst acidity. 14 references.