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Sample records for stable tricyclic aromatic

  1. Tricyclic Antidepressants

    Science.gov (United States)

    Schmidt, Gary J.

    The use of tricyclic antidepressant drugs is becoming increasingly prevalent for the treatment of depressed patients. It has been suggested that, analogous to many other drug substances, the tricyclic drugs exhibit clinical effectiveness within a defined therapeutic concentration range (1-10). Very recently, both Dito (11) and Orsulak and Schildkraut (12) have summarized the usefulness of measuring serum concentrations of these drugs. These authors suggest that knowledge of the plasma concentrations of these drugs aid the physician in determining patient compliance and initiating the best possible drug treatment.

  2. Tricyclic antidepressant radioreceptor assay

    International Nuclear Information System (INIS)

    Innis, R.B.; Tune, L.; Rock, R.; Depaulo, R.; U'Prichard, D.C.; Snyder, S.M.

    1979-01-01

    A receptor assay for tricyclic antidepressants described here is based on the ability of these drugs to compete with [ 3 H]-3-guinuclidnyl benzilate ( 3 H-QNB) for binding to muscarinic cholinergic receptors in rat brain membranes. The assay is sensitive, in that it can detect, for example, 2ng/ml nortriptyline in plasma. Seven plasma samples from depressed patients treated with nortriptyline were assayed with the radioreceptor and gas liquid chromatographic methods, and the results from these two methods were almost identical. This assay should be used cautiously, if at all, in patients treated with other drugs that have potent anticholinergic effects. (Auth.)

  3. Tricyclic antidepressant overdose necessitating ICU admission ...

    African Journals Online (AJOL)

    Tricyclic antidepressant (TCA) overdose necessitating intensive care unit (ICU) admission remains a significant problem in the Western Cape. In this retrospective study, we reviewed the course of life-threatening TCA overdose in our centre to identify potential prognostic indicators. TCA levels >1 000 ng/ml were associated ...

  4. Tritiation of unsaturated tricyclic antidepressants for radioimmunoassay

    International Nuclear Information System (INIS)

    Buchman, O.; Azran, J.; Shimoni, M.

    1983-01-01

    A rapid and convenient method to obtain specific an high activity tritium labelling of tricyclic antidepressants which have a double bond, is described. The procedure is based on the halogenation of the active benzylic positions of the unlabelled material and the selective catalytic removal of the halogen atom by tritium in the presence of a base which inhibits the attack on the olefin bond

  5. Response to tricyclic antidepressants: independent of gender?

    NARCIS (Netherlands)

    Wohlfarth, Tamar; Storosum, Jitschak G.; Elferink, André J. A.; van Zwieten, Barbara J.; Fouwels, Annemarie; van den Brink, Wim

    2004-01-01

    OBJECTIVE: The authors examined gender differences in response to tricyclic antidepressants. METHOD: A total of 30 randomized, placebo-controlled trials that included 3,886 patients (1,555 men and 2,331 women), submitted between 1979 and 1991 in order to obtain marketing authorization, were

  6. Unconventional, Chemically Stable, and Soluble Two-Dimensional Angular Polycyclic Aromatic Hydrocarbons: From Molecular Design to Device Applications

    KAUST Repository

    Zhang, Lei

    2015-03-17

    Polycyclic aromatic hydrocarbons (PAHs), consisting of laterally fused benzene rings, are among the most widely studied small-molecule organic semiconductors, with potential applications in organic field-effect transistors (OFETs) and organic photovoltaics (OPVs). Linear acenes, including tetracene, pentacene, and their derivatives, have received particular attention due to the synthetic flexibility in tuning their chemical structure and properties and to their high device performance. Unfortunately, longer acenes, which could exhibit even better performance, are susceptible to oxidation, photodegradation, and, in solar cells which contain fullerenes, Diels-Alder reactions. This Account highlights recent advances in the molecular design of two-dimensional (2-D) PAHs that combine device performance with environmental stability. New synthetic techniques have been developed to create stable PAHs that extend conjugation in two dimensions. The stability of these novel compounds is consistent with Clar\\'s sextet rule as the 2-D PAHs have greater numbers of sextets in their ground-state configuration than their linear analogues. The ionization potentials (IPs) of nonlinear acenes decrease more slowly with annellation in comparison to their linear counterparts. As a result, 2-D bistetracene derivatives that are composed of eight fused benzene rings are measured to be about 200 times more stable in chlorinated organic solvents than pentacene derivatives with only five fused rings.Single crystals of the bistetracene derivatives have hole mobilities, measured in OFET configuration, up to 6.1 cm2 V-1 s-1, with remarkable Ion/Ioff ratios of 107. The density functional theory (DFT) calculations can provide insight into the electronic structures at both molecular and material levels and to evaluate the main charge-transport parameters. The 2-D acenes with large aspect ratios and appropriate substituents have the potential to provide favorable interstack electronic interactions

  7. Thermally stable aromatic amine derivative with symmetrically substituted double spirobifluorene core as a hole transport material for green phosphorescent organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Joo; Lee, Jun Yeob, E-mail: leej17@dankook.ac.kr

    2012-11-01

    A thermally stable aromatic amine derivative with a symmetrically substituted double spirobifluorene core was synthesized as a hole transport material for green phosphorescent organic light-emitting diodes. A high glass transition temperature of 142 Degree-Sign C was obtained and a film morphology of the hole transport material was kept stable up to 120 Degree-Sign C. The hole transport material showed a high triplet energy of 2.53 eV and a quantum efficiency of 17.4% in green phosphorescent organic light-emitting diodes. - Highlights: Black-Right-Pointing-Pointer Synthesis of symmetrically substituted double spirobifluorene core Black-Right-Pointing-Pointer Stable film morphology up to 120 Degree-Sign C Black-Right-Pointing-Pointer High quantum efficiency in green phosphorescent organic light emitting diode.

  8. Poisoining with Tricyclic Antidepressants and Current Treatment

    Directory of Open Access Journals (Sweden)

    Muge Gulen

    2016-12-01

    Full Text Available Poisoning with tricyclic antidepressants is one of the main causes of morbidity and mortality compared to all the antidepressants. Main toxic effects are on the cardiovascular system and central nervous system and manifests itself as anticholinergic symptoms. There is no antidote known to be used in the treatment. But sodium bicarbonate treatment is effective in preventing ventricular arrhythmias and hypotension, and resolving metabolic acidosis. There are some treatments that has been used for relief of symptoms and some of them still are in research stage. The drugs that are used can be customized according to the patients symptoms. [Archives Medical Review Journal 2016; 25(4.000: 608-621

  9. Extracorporeal treatment for tricyclic antidepressant poisoning

    DEFF Research Database (Denmark)

    Yates, Christopher; Galvao, Tais; Sowinski, Kevin M

    2014-01-01

    methodology, the subgroup responsible for this poison reviewed the articles, extracted the data, summarized findings, and proposed structured voting statements following a predetermined format. A two-round modified Delphi method was chosen to reach a consensus on voting statements and RAND......The Extracorporeal Treatments In Poisoning (EXTRIP) workgroup was formed to provide recommendations on the use of extracorporeal treatments (ECTR) in poisoning. Here, the workgroup presents its results for tricyclic antidepressants (TCAs). After an extensive literature search, using a predefined...... yielding a very low quality of evidence for all recommendations. Data on 108 patients, including 12 fatalities, were abstracted. The workgroup concluded that TCAs are not dialyzable and made the following recommendation: ECTR is not recommended in severe TCA poisoning (1D). The workgroup considers...

  10. Radiographic abnormalities in tricyclic acid overdose

    International Nuclear Information System (INIS)

    Varnell, R.M.; Richardson, M.L.; Vincent, J.M.; Godwin, J.D.

    1987-01-01

    Several case reports have described adult respiratory distress syndrome (ARDS) secondary to tricyclic acid (TCA) overdose. During a 1-year period 83 patients requiring intubation secondary to drug overdose were evaluated. Abnormalities on chest radiographs occurred in 26 (50%) of the 54 patients with TCA overdose, compared to six (21%) of the 29 patients overdosed with other drugs. In addition, five (9%) of the patients with TCA overdose subsequently had radiographic and clinical abnormalities meeting the criteria for ARDS. Only one (3%) of the patients with non-TCA overdose subsequently had change suggesting ARDS. TCAs should be added to the list of drugs associated with ARDS, and TCA overdose should be considered a major risk factor in the development of radiographically evident abnormalities

  11. Tricyclic sesquiterpene copaene prevents H2O2-induced neurotoxicity

    Directory of Open Access Journals (Sweden)

    Hasan Turkez

    2014-02-01

    Full Text Available Aim: Copaene (COP, a tricyclic sesquiterpene, is present in several essential oils of medicinal and aromatic plants and has antioxidant and anticarcinogenic features. But, very little information is known about the effects of COP on oxidative stress induced neurotoxicity. Method: We used hydrogen peroxide (H2O2 exposure for 6 h to model oxidative stress. Therefore, this experimental design allowed us to explore the neuroprotective potential of COP in H2O2-induced toxicity in rat cerebral cortex cell cultures for the first time. For this purpose, methyl thiazolyl tetrazolium (MTT and lactate dehydrogenase (LDH release assays were carried out to evaluate cytotoxicity. Total antioxidant capacity (TAC and total oxidative stress (TOS parameters were used to evaluate oxidative changes. In addition to determining of 8-hydroxy-2-deoxyguanosine (8-OH-dG levels, the single cell gel electrophoresis (SCGE or comet assay was also performed for measuring the resistance of neuronal DNA to H2O2-induced challenge. Result: The results of this study showed that survival and TAC levels of the cells decreased, while TOS, 8-OH-dG levels and the mean values of the total scores of cells showing DNA damage increased in the H2O2 alone treated cultures. But pre-treatment of COP suppressed the cytotoxicity, genotoxicity and oxidative stress which were increased by H2O2. Conclusion: It is proposed that COP as a natural product with an antioxidant capacity in mitigating oxidative injuries in the field of neurodegenerative diseases. [J Intercult Ethnopharmacol 2014; 3(1.000: 21-28

  12. Synthesis and evaluation of aromaticity and tautomerization of ...

    Indian Academy of Sciences (India)

    Nurettin Menges

    the nucleus-independent chemical shift (NICS), has been proposed by Schleyer et al.11 It has been reported that the negative value of the absolute shielding was ...... titative Measures of Aromaticity for Mono-, Bi-, and. Tricyclic Penta- and Hexaatomic Heteroaromatic Ring. Systems and Their Interrelationships, Chem. Rev.

  13. Tricyclic Neovibsanin Scaffold Inhibits Glioma by Targeting Glioma ...

    African Journals Online (AJOL)

    Purpose: To investigate the effect of tricyclic neovibsanin scaffold (TCNS) on cell viability, colony formation capacity and induction of apoptosis in glioma cells. Methods: 3-(4, 5-Dimethylthiazol-2-yl) 2, 5-diphe¬nyltetrazolium bromide (MTT) assay was used to analyze the effect of TCNS on cell proliferation. Light microscopic ...

  14. Structural, elastic, electronic, and optical properties of the tricycle-like phosphorene.

    Science.gov (United States)

    Zhang, Yang; Wu, Zhi-Feng; Gao, Peng-Fei; Fang, Dang-Qi; Zhang, Er-Hu; Zhang, Sheng-Li

    2017-01-18

    Phosphorene exhibits great potential applications in nanoelectronics due to its relatively large and direct band gap and good charge carrier mobility, and thus has attracted extensive attentions over the past few years. In this study, a novel hybrid phosphorene with a tricycle-like bulge is proposed using density functional theory calculations. Herein, structural stability, elastic, electronic, and optical properties have been addressed. It is found that all the hybrid phosphorenes are stable, and their cohesive energies are very close to that of black phosphorene monolayer. Due to the tricycle-like bulge, these hybrid layers are much softer than the black phosphorene. Their electronic band structures show that they are semiconductors with a robust indirect band gap, and their band gaps are strongly dependent on the sizes. Spatial charge distribution to the valence band maximum and the conduction band minimum is analyzed to explore the origin of the indirect band gap features. By calculating the complex dielectric function, optical properties have been discussed. Our results suggest that the hybrid phosphorenes with well structural stability, robust indirect band gaps, flexible property, and good optical absorption hold great promise for applications in the field of visible light harvesting and flexible nanoelectronic devices.

  15. Radioimmunoassay for nortriptyline (and other tricyclic antidepressants) in plasma

    International Nuclear Information System (INIS)

    Maguire, K.P.; Burrows, G.D.; Norman, T.R.; Scoggins, B.A.

    1978-01-01

    The radioimmunoassay for nortriptyline described here can detect as little 1 μg/liter of plasma. Within-day precision and day-to-day precision (CV) were +-6 and +-11%, respectively, over the concentration range 100 to 200 μg/liter. The major metabolite hydroxy-nortriptyline does not cross react with the antiserum. Results so obtained correlate closely with results by a double-isotope derivative dilution technique. The major advantages of this technique over currently available methods are its sensitivity, convenience (many samples can be processed in one day), simplicity, and cost. Further, prior extraction of plasma samples is not required. Cross-reactivity studies have been carried out with all other available tricyclic antidepressants. The antiserum has the ability to bind these drugs, thus radioimmunoassay for all the tricyclic antidepressant drugs can be set up because concurrent use of more than one of these drugs is rare

  16. Synthesis of tricyclic butenolides and comparison their effects with known smoke-butenolide, KAR1.

    Science.gov (United States)

    Krawczyk, Ewa; Koprowski, Marek; Cembrowska-Lech, Danuta; Wójcik, Agata; Kępczyński, Jan

    2017-08-01

    Plant-derived smoke - butenolide, called at present karrikin 1 (KAR 1 ) is known as an important inductor of seed germination and seedling growth. In this study, tricyclic butenolides were synthesized and their effects on germination of dormant and non-dormant Avena fatua caryopses were compared, as were also their effects versus those of KAR 1 on seedling growth. KAR 1 was found to be most effective and to completely remove dormancy. Butenolides, rac-8 and (S)-8a, showed a low stimulatory effect on germination of dormant caryopses, visible only when applied at very high concentrations. These compounds used at concentrations 100 times those of KAR 1 similarly increased the speed of germination and vigor of non-dormant caryopses. Likewise, growth of coleoptiles and their fresh weight were increased by KAR 1 as well as by rac-8 and (S)-8a to a similar value. KAR 1 and rac-8 were more effective than (S)-8a in increasing root growth. The results shown indicate that the presence of an aromatic ring in the absence of methyl group at C3 induced a much lower, or a similar, effect on germination of dormant and non-dormant Avena fatua caryopses and seedling growth compared to KAR 1 , but only when used at much higher concentrations. The simultaneous presence of a methyl group at C3 and an aromatic ring in the compound rac-7 exerted only a slight effect on the root growth. Copyright © 2017 Elsevier GmbH. All rights reserved.

  17. Inhibition of acid sphingomyelinase by tricyclic antidepressants and analogons

    Directory of Open Access Journals (Sweden)

    Nadine eBeckmann

    2014-09-01

    Full Text Available Amitriptyline, a tricyclic antidepressant, has been used in the clinic to treat a number of disorders, in particular major depression and neuropathic pain. In the 1970s the ability of tricyclic antidepressants to inhibit acid sphingomyelinase (ASM was discovered. The enzyme ASM catalyzes the hydrolysis of sphingomyelin to ceramide. ASM and ceramide were shown to play a crucial role in a wide range of diseases, including cancer, cystic fibrosis, diabetes, Alzheimer’s disease and major depression, as well as viral (e.g. measles virus and bacterial (e.g. Staphylococcus aureus, Pseudomonas aeruginosa infections. Ceramide molecules may act in these diseases by the alteration of membrane biophysics, the self-association of ceramide molecules within the cell membrane and the ultimate formation of larger ceramide-enriched membrane domains/platforms. These domains were shown to serve the clustering of certain receptors such as CD95 and may also act in the above named diseases. The potential to block the generation of ceramide by inhibiting the ASM has opened up new therapeutic approaches for the treatment of these conditions. Since amitriptyline is one of the longest used clinical drugs and side effects are well studied, it could potentially become a cheap and easily accessible medication for patients suffering from these diseases. In this review, we aim to provide an overview of current in vitro and in vivo studies and clinical trials utilizing amitriptyline to inhibit ASM and contemplate possible future applications of the drug.

  18. Reconstruction of floral changes during deposition of the Miocene Embalut coal from Kutai Basin, Mahakam Delta, East Kalimantan, Indonesia by use of aromatic hydrocarbon composition and stable carbon isotope ratios of organic matter

    Energy Technology Data Exchange (ETDEWEB)

    Widodo, S.; Bechtel, A.; Anggayana, K.; Puttmann, W. [University of Frankfurt, Frankfurt (Germany)

    2009-02-15

    The distribution of aromatic hydrocarbons and stable carbon isotope ratios of organic matter in a series of nine Miocene Embalut coal samples obtained from nine coal seams of Kutai Basin, East Kalimantan, Indonesia were studied. The rank of the Embalut coals ranged from lignites to low rank sub-bituminous coals (0.36-0.50% Rr), based on measurements of huminite reflectance. The aromatic hydrocarbon fractions of all coal samples were dominated by cadalene in the lower boiling point range and picene derivatives in the higher boiling point range of the gas chromatograms. Cadalene can be attributed to the contribution of Dipterocarpaceae and various hydrated picenes to the contribution of additional angiosperms to the coal forming vegetation. The picenes originate from {alpha}- and {beta}-amyrin. However, in some coal samples minor amounts of simonellite and retene were also detected which argues for an additional contribution of gymnosperms (conifers) to coal forming vegetation preferentially in the Middle Miocene and at the beginning of the Late Miocene. The results of stable carbon isotope ratios ({delta}{sup 13}C in most of the coal samples are consistent with their origin from angiosperms {delta}{sup 13}C between -27.09, and -28.0%). During the Miocene the climate of Mahakam Delta was not uniformly moist and cooler than the present day climate. This would have been favourable for the growth of conifers, especially in the montane forests. The contribution of conifers to the Embalut coals might be a result of the cool Middle/Late Miocene climate during peat accumulation in the Kutai Basin.

  19. Tricyclic drugs for depression in children and adolescents.

    Science.gov (United States)

    Hazell, Philip; Mirzaie, Mohsen

    2013-06-18

    There is a need to identify effective and safe treatments for depression in children and adolescents. While tricyclic drugs are effective in treating depression in adults, individual studies involving children and adolescents have been equivocal. Prescribing of tricyclic drugs for depression in children and adolescents is now uncommon, but an accurate estimate of their efficacy is helpful as a comparator for other drug treatments for depression in this age group. This is an update of a Cochrane review first published in 2000 and updated in 2002, 2006 and 2010. To assess the effects of tricyclic drugs compared with placebo for depression in children and adolescents and to determine whether there are differential responses to tricyclic drugs between child and adolescent patient populations. We conducted a search of the Cochrane Depression, Anxiety and Neurosis Review Group's Specialised Register (CCDANCTR) (to 12 April 2013), which includes relevant randomised controlled trials from the following bibliographic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (all years), EMBASE (1974-), MEDLINE (1950-) and PsycINFO (1967-). The bibliographies of previously published reviews and papers describing original research were cross-checked. We contacted authors of relevant abstracts in conference proceedings of the American Academy of Child and Adolescent Psychiatry, and we handsearched the Journal of the American Academy of Child and Adolescent Psychiatry (1978 to 1999). Randomised controlled trials comparing the efficacy of orally administered tricyclic drugs with placebo in depressed people aged 6 to 18 years. One of two review authors selected the trials, assessed their quality, and extracted trial and outcome data. A second review author assessed quality and checked accuracy of extracted data. Most studies reported multiple outcome measures including depression scales and clinical global impression scales. For each study, we took the best

  20. Activation of electrophilicity of stable Y-delocalized carbamate cations in intramolecular aromatic substitution reaction: evidence for formation of diprotonated carbamates leading to generation of isocyanates.

    Science.gov (United States)

    Kurouchi, Hiroaki; Kawamoto, Kyoko; Sugimoto, Hiromichi; Nakamura, Satoshi; Otani, Yuko; Ohwada, Tomohiko

    2012-10-19

    Although cations with three heteroatoms, such as monoprotonated guanidine and urea, are stabilized by Y-shaped conjugation and such Y-conjugated cations are sufficiently basic to be further protonated (or protosolvated) to dications in strongly acid media, only O-monoprotonated species have been detected in the case of carbamates even in magic acid. We found that the trifluoromethanesulfonic acid-catalyzed cyclization of arylethylcarbamates proceeds to afford dihydroisoquinolones in high yield. In strong acids, methyl carbamates are fully O-monoprotonated, and these monocations do not undergo cyclization even under heating. But, as the acidity of the reaction medium is further increased, the cyclization reaction of methyl phenethylcarbamates starts to proceed as a first-order reaction, with a linear relationship between rate and acidity. The sign and magnitude of the entropy of activation ΔS(‡) were found to be similar to those of other A(Ac)1 reactions. These results strongly support the idea that further protonation of the O-protonated carbamates is involved in the cyclization, but the concentration of the dications is very low and suggests that the rate-determining step is dissociation of methanol from the diprotonated carbamate to generate protonated isocyanate, which reacts with the aromatic ring. Therefore, O-protonated carbamates are weak bases in sharp contrast to other Y-shaped monocations.

  1. Annulation of aromatic imines via directed C-H bond activation.

    Science.gov (United States)

    Thalji, Reema K; Ahrendt, Kateri A; Bergman, Robert G; Ellman, Jonathan A

    2005-08-19

    A directed C-H bond activation approach to the synthesis of indans, tetralins, dihydrofurans, dihydroindoles, and other polycyclic aromatic compounds is presented. Cyclization of aromatic ketimines and aldimines containing alkenyl groups tethered at the meta position relative to the imine directing group has been achieved using (PPh3)3RhCl (Wilkinson's catalyst). The cyclization of a range of aromatic ketimines and aldimines provides bi- and tricyclic ring systems with good regioselectivity. Different ring sizes and substitution patterns can be accessed through the coupling of monosubstituted, 1,1- or 1,2-disubstituted, and trisubstituted alkenes bearing both electron-rich and electron-deficient functionality.

  2. Characterization of tdt genes for the degradation of tricyclic diterpenes by Pseudomonas diterpeniphila A19-6a.

    Science.gov (United States)

    Morgan, C A; Wyndham, R C

    2002-01-01

    Resin acids are tricyclic diterpenes that are toxic to aquatic life when released in high concentrations in pulp mill effluents. These naturally formed organic acids are readily degraded by bacteria and fungi; nevertheless, many of the mechanisms involved are still unknown. We report the localization, cloning, and sequencing of genes for abietane degradation (9.18 kb; designated tdt (tricyclic diterpene) LRSABCD) from the gamma-Proteobacterium Pseudomonas diterpeniphila A19-6a. Using gene knockout mutants, we demonstrate that tdtL, encoding a putative CoA ligase, is required for growth on abietic and dehydroabietic acids. A second gene knockout in tdtD, encoding a putative cytochrome P450 monooxygenase, reduced the growth of strain A19-6a on abietic and dehydroabietic acids as sole sources of carbon and energy, but did not eliminate growth. The degree of homology between P450TdtD and P450TerpC, the closest known P450 homologue to TdtD, identifies TdtD as a new member of the P450 superfamily. Hybridization of six of the tdt genes to genomic DNA of a related resin acid degrading bacterium Pseudomonas abietaniphila BKME-9 identified tdt homologues in this strain that utilizes aromatic ring dioxygenase genes (dit) to open the ring structure of abietic and dehydroabietic acids. These results suggest the tdt and dit genes may function in concert to allow these Pseudomonas strains to degrade resin acids. Homologues of several of the tdt genes were detected in resin acid degrading Ralstonia and Comamonas species within the beta- and gamma-Proteobacteria.

  3. Cardiotoxicity of tricyclic antidepressant treated by 2650 mEq sodium bicarbonate: A case report

    Directory of Open Access Journals (Sweden)

    Hassan Amiri

    2016-12-01

    Full Text Available Poisoning with tricyclic antidepressants is an important cause of drug-related self-poisoning in the developed world and a very common cause of poisoning and mortality in developing countries. Electrocardiographic manifestations of most tricyclic antidepressant-poisoned patients resolve by the administration of 1–2 mEq/kg of sodium bicarbonate. Some rare cases have been reported who have been resistant to the long-term or high doses of bicarbonate administration. We present a case of acute tricyclic antidepressant toxicity referring with status epilepticus, hypotension, and refractory QRS complex widening that resolved after the intravenous administration of 2650 mEq sodium bicarbonate.

  4. Synthesis of a tricyclic lactam via Beckmann rearrangement and ring-rearrangement metathesis as key steps

    Directory of Open Access Journals (Sweden)

    Sambasivarao Kotha

    2015-08-01

    Full Text Available A tricyclic lactam is reported in a four step synthesis sequence via Beckmann rearrangement and ring-rearrangement metathesis as key steps. Here, we used a simple starting material such as dicyclopentadiene.

  5. Ergonomic Analysis of Tricycle Sidecar Seats: Basis for Proposed Standard Design

    Directory of Open Access Journals (Sweden)

    Michael C. Godoy

    2015-12-01

    Full Text Available Ergonomics (also called human factors engineering is the study of human characteristics for the appropriate design of the living and work environment. It is applied in various industrial areas which includes transportation.Tricycle being one of the most common means of public transportation in Lipa City has various adaptations to suit the culture, and environment. The purpose of this study is to analyze the variability in design of the tricycles in Lipa City, Philippines and propose a standard ergonomically designed tricycle sidecar seat for a greater population. The study was conducted at 26 tricycle terminals with 232 tricycle samples within Lipa City proper including the public market area where 400 commuters were given questionnaires to determine the risk factors associated with the existing tricycle sidecar seat design. Anthropometric measurements of 100 males and 100 female commuters were obtained together with the sidecar dimensions of 232 tricycles to substantiate the observed variations in design. Using the design for the average and design for the extremes, it was found out that most of the tricycles in Lipa City, Philippines have inappropriate inclined seat and lowered sidecar seat pan height which can result to leg and abdominal pain; narrowed seat pan depth which caused pressure on buttocks and legs; narrowed backrest width which can cause upper and low back pain; low backrest height that can pose upper back pain; which can also result to abdominal pain; inclined backrest and limited vertical clearance which can cause upper back pain and neck pain. The researcher proposed a sidecar seat design standard which can be used by the Land Transportation Office, and Land Transportation Franchising and Regulatory Board to provide ease, comfort, and convenience to the passengers.

  6. The radioimmunoassay of clomipramine (Anafranil-Geigy): a tricyclic antidepressant

    International Nuclear Information System (INIS)

    Read, G.F.; Riad-Fahmy, D.

    1977-01-01

    A radioimmunoassay has been developed for the tricyclic antidepressant, clomipramine (Anafranil-Geigy) which allows accurate determination of plasma levels without a pr-assay purification step. This is achieved by generation of specific antisera using an antigen produced by conjugation of clomipramine to bovine serum albumin via the 10,11 bridge positions. As expected cross reaction of the pharmacologically active major metabolite, desmethylclomipramine was 5% and that of didesmethyclomipramine 1%. Specificity was confirmed by comparing titres achieved in the routine assay with those observed in an assay incorporating a pre-assay thin layer chromatographic purification step. Pharmacokinetic data were in agreement with double radioisotope derivative assays and also with previously reported assays using G.C. or G.C./M.S. techniques. The sensitivity is superior to any previous assay known to us for this class of compound. The specificity and precision, coupled with the high sample turnover (greater than 300 samples/week per technician) make the assay ideal for supervision of patient compliance and routine assay of samples generated in large clinical trials. (orig.) [de

  7. Aromatic graphene

    Energy Technology Data Exchange (ETDEWEB)

    Das, D. K., E-mail: gour.netai@gmail.com [Department of Metallurgical and Material Science Engineering, National Institute of Technology Durgapur-713209, West Bengal (India); Sahoo, S., E-mail: sukadevsahoo@yahoo.com [Department of Physics, National Institute of Technology Durgapur-713209, West Bengal (India)

    2016-04-13

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  8. Aromatic graphene

    International Nuclear Information System (INIS)

    Das, D. K.; Sahoo, S.

    2016-01-01

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  9. Polycyclic aromatic hydrocarbons (PAHs) in wetland soils under different land uses in a coastal estuary: toxic levels, sources and relationships with soil organic matter and water-stable aggregates.

    Science.gov (United States)

    Xiao, Rong; Bai, Junhong; Wang, Junjing; Lu, Qiongqiong; Zhao, Qingqing; Cui, Baoshan; Liu, Xinhui

    2014-09-01

    The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the soils from industrial, wharf, cropland, milldam and natural wetland sites to characterize their distributions, toxic levels and possible sources in the Pearl River Estuary and identify their relationships with soil organic matter (SOM) and water-stable aggregates (WSAs). Our results indicate that the average concentration of total PAHs in this region reached a moderate pollution level, which was higher than that in other larger estuaries in Asia. The average level of total PAHs in industrial soils was 1.2, 1.5, 1.6 and 2.3 times higher than those in soils from wharf, cropland, milldam and natural wetland sites, respectively. Greater accumulation of PAHs occurred in the middle and/or bottom soil layers where 3-ring PAHs were dominant. Industrial soils also exhibited the highest toxic levels with the highest toxic equivalent concentrations of PAHs, followed by wharf and milldam soils, and the cropland and wetland soils had the lowest toxicity. The diagnostic ratios suggested that PAHs primarily originated from biomass and coal combustion at industrial and milldam sites, and petroleum combustion was determined to be the primary source of PAHs at the wharf, cropland and wetland sites. Both 3-ring and 4-ring PAHs in the milldam and wharf soils were significantly positively correlated with the SOM, whereas the 4,5,6-ring PAHs and total PAHs in industrial soils and the 2-ring PAHs in cropland soils were significantly negatively correlated with the SOM. In addition, large WSAs also exhibited a significant positive correlation with PAHs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Antidepressant-induced lipidosis with special reference to tricyclic compounds.

    Science.gov (United States)

    Xia, Z; Ying, G; Hansson, A L; Karlsson, H; Xie, Y; Bergstrand, A; DePierre, J W; Nässberger, L

    2000-04-01

    Cationic amphiphilic drugs, in general, induce phospholipid disturbances. Tricyclic, as well as other antidepressants belong to this group. In experimental animals, antidepressants induce lipid storage disorders in cells of most organs, a so-called generalized phospholipidosis. This disorder is conveniently detected by electron microscopic examination revealing myelin figures. Myelin figures or myeloid bodies are subcellular organelles containing unicentric lamellar layers. The lipidotic induction potency during in vivo is related to the apolarity of the compound. Metabolism of phospholipids takes place within the cell continuously. Several underlying mechanisms may be responsible for the induction of the phospholipid disturbance. For instance, it has been suggested that the compounds bind to phospholipids and such binding may alter the phospholipid's suitability as a substrate for phospholipases. Free TCA or metabolites thereof may also inhibit phospholipases directly, as has been demonstrated for sphingomyelinase in glioma and neuroblastoma cells. Both these mechanisms might result in phospholipidosis. Interaction between drug and phospholipid bilayer has been investigated by nuclear magnetic resonance technique. There seems to be large differences in the sensitivities amongst different organs. Steroid-producing cells of the adrenal cortex, testis and ovaries are in particular susceptible to drug-induced lipidosis. The so-called foam cells are lung macrophages located in the interstitium which become densely packed with myelin figures during TCA exposure. It requires about 3-6 weeks of treatment to develop this converted cell. In cell cultures however, phospholipidosis is demonstrated already after 24 h only. It appears that the cells that undergo TCA-induced lipidosis may recover after withdrawal of the drug. The time required to achieve complete recovery ranges from 3-4 weeks to several months, depending on the organ affected. Little is known about the

  11. Anti-Nociceptive Effect of Tricyclic Anti-Depressants Following Intrathecal Administration

    Science.gov (United States)

    Kehl, Lois J.; Wilcox, George L.

    1984-01-01

    The anti-nociceptive effects of three tricyclic anti-depressants (desipramine, protriptyline, fluoxetine) were evaluated in mice following intrathecal administration. Nociceptive behavior was produced by intrathecal administration of Substance P and measured for 60 seconds following subcutaneous and intrathecal administration of vehicle and increasing doses of the drugs being tested. Systemically administered protriptyline produced dose related antinociception in this paradigm. A similar effect was seen following systemic desipramine; while fluoxetine was inactive systemically. Both protriptyline and desipramine given intrathecally were antinociceptive while fluoxetine had a biphasic effect, being analgesic only at low doses. These results indicate that tricyclic antidepressants may produce analgesia at the spinal level in rodents. This action may be related to the therapeutic success of tricyclic antidepressants in chronic pain syndromes. PMID:6335632

  12. Get Your Hotel Operations Team Onboard The Tricycle of Guest Service

    OpenAIRE

    Kennedy, Doug

    2018-01-01

    As hospitality industry trainers know, using symbols and models can help trainees grasp abstract concepts and make seemingly-complex paradigms easy to understand. Seems like is a good time for the hotel industry to update its model, so let’s get your team onboard The Tricycle of Guest Service. When you think about it, a tricycle is a perfect model for a positive guest experience. For one, it has three wheels, just like the three components of a memorable guest stay. The back wheels repres...

  13. Short-term efficacy of tricyclic antidepressants revisited: a meta-analytic study

    NARCIS (Netherlands)

    Storosum, J. G.; Elferink, A. J.; van Zwieten, B. J.; van den Brink, W.; Gersons, B. P.; van Strik, R.; Broekmans, A. W.

    2001-01-01

    The original data from the placebo-arms and the tricyclic-arms of all parallel randomized controlled three-arm studies, which had been conducted in the period 1979-1991 for a drug under development in order to obtain marketing authorization for the indication major depression, were included in a

  14. Intramolecular Morita-Baylis-Hillman reaction as a strategy for the construction of tricyclic sesquiterpene cores.

    Science.gov (United States)

    Peter, Clovis; Geoffroy, Philippe; Miesch, Michel

    2018-02-21

    Starting from a common polyfunctionalized bicyclo[3.2.1]octane-6,8-dione intermediate, a concise synthetic route to tricyclic cores found in quadrane, suberosane, cedrane and related sesquiterpenes was developed using a Morita-Baylis-Hillman intramolecular reaction as a key step.

  15. [Analysis of aromatic hydrocarbons in cracking products of jet fuel by comprehensive two-dimensional gas chromatography-mass spectrometry].

    Science.gov (United States)

    Li, Haijing; Zhang, Xiangwen

    2017-08-08

    As coking precursors, aromatic hydrocarbons have an effect on the cracking stability of fuels. A method for identifying and quantitating aromatics in the supercritical cracking products of jet fuel was established by comprehensive two-dimensional gas chromatography coupled with mass spectrometry (GC×GC-MS). The effects of main chromatographic conditions such as initial oven temperature and modulation period on the separation of supercritical cracking products were studied. The method has good separation ability for polycyclic aromatic hydrocarbons (PAH) isomers. A total of 27 aromatics, including monocyclic aromatic hydrocarbons, bicyclic aromatic hydrocarbons, tricyclic aromatic hydrocarbons, tetracyclic aromatic hydrocarbons, etc., were identified based on standard mass spectra, the retention times of standards and literature reports. Moreover, the corresponding quantitative determination was achieved by external standard method of GC×GC-FID. The results showed that the contents of aromatics increased with the increase of gas yield. When gas yield reached 22%, the bicyclic aromatic hydrocarbons began to produce, and their contents increased exponentially with the increase of gas yield. Compared with the traditional GC-MS, the method has better separation and qualitative ability, and can be applied to the separation of complex samples and qualitative and quantitative analyses of cracking products.

  16. Annulation of Aromatic Imines via Directed C-H BondActivation

    Energy Technology Data Exchange (ETDEWEB)

    Thalji, Reema K.; Ahrendt, Kateri A.; Bergman, Robert G.; Ellman,Jonathan A.

    2005-04-14

    A directed C-H bond activation approach to the synthesis of indans, tetralins, dihydrofurans, dihydroindoles, and other polycyclic aromatic compounds is presented. Cyclization of aromatic ketimines and aldimines containing alkenyl groups tethered at the meta position relative to the imine directing group has been achieved using (PPh{sub 3}){sub 3}RhCl (Wilkinson's catalyst). The cyclization of a range of aromatic ketimines and aldimines provides bi- and tricyclic ring systems with good regioselectivity. Different ring sizes and substitution patterns can be accessed through the coupling of monosubstituted, 1,1- or 1,2-disubstituted, and trisubstituted alkenes bearing both electron-rich and electron-deficient functionality.

  17. Interaction of tricyclic drugs with copper phthalocyanine dye immobilized on magnetic carriers

    Czech Academy of Sciences Publication Activity Database

    Šafaříková, Miroslava; Šafařík, Ivo

    3(Suppl.2), - (2002), s. 188-191 ISSN 1473-2262. [International Conference on the Scientific and Clinical Applications of Magnetic Carriers /4./. Tallahassee, 09.05.2002-11.05.2002] R&D Projects: GA MŠk OC 523.80; GA AV ČR IBS6087204 Institutional research plan: CEZ:AV0Z6087904 Keywords : magnetic * tricyclic drugs * phthalocyanine Subject RIV: CE - Biochemistry

  18. Formation of an Angular Aromatic Polyketide from a Linear Anthrene Precursor via Oxidative Rearrangement.

    Science.gov (United States)

    Gao, Guixi; Liu, Xiangyang; Xu, Min; Wang, Yemin; Zhang, Fei; Xu, Lijun; Lv, Jin; Long, Qingshan; Kang, Qianjin; Ou, Hong-Yu; Wang, Ying; Rohr, Jürgen; Deng, Zixin; Jiang, Ming; Lin, Shuangjun; Tao, Meifeng

    2017-07-20

    Bacterial aromatic polyketides are a group of natural products synthesized by polyketide synthases (PKSs) that show diverse structures and biological activities. They are structurally subclassified into linear, angular, and discoid aromatic polyketides, the formation of which is commonly determined by the shaping and folding of the poly-β-keto intermediates under the concerted actions of the minimal PKSs, cyclases and ketoreductases. Murayaquinone, found in several streptomycetes, possesses an unusual tricyclic angular aromatic polyketide core containing a 9,10-phenanthraquinone. In this study, genes essential for murayaquinone biosynthesis were identified, and a linear anthraoxirene intermediate was discovered. A unique biosynthetic model for the angular aromatic polyketide formation was discovered and confirmed through in vivo and in vitro studies. Three oxidoreductases, MrqO3, MrqO6, and MrqO7, were identified to catalyze the conversion of the linear aromatic polyketide intermediate into the final angularly arranged framework, which exemplifies a novel strategy for the biosynthesis of angular aromatic polyketides. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Smooth Jerk-Bounded Optimal Path Planning of Tricycle Wheeled Mobile Manipulators in the Presence of Environmental Obstacles

    Directory of Open Access Journals (Sweden)

    Moharam Habibnejad Korayem

    2012-10-01

    Full Text Available In this work, a computational algorithm is developed for the smooth-jerk optimal path planning of tricycle wheeled mobile manipulators in an obstructed environment. Due to a centred orientable wheel, the tricycle mobile manipulator exhibits more steerability and manoeuvrability over traditional mobile manipulators, especially in the presence of environmental obstacles. This paper presents a general formulation based on the combination of the potential field method and optimal control theory in order to plan the smooth point-to-point path of the tricycle mobile manipulators. The nonholonomic constraints of the tricycle mobile base are taken into account in the dynamic formulation of the system and then the optimality conditions are derived considering jerk restrictions and obstacle avoidance. Furthermore, by means of the potential field method, a new formulation of a repulsive potential function is proposed for collision avoidance between any obstacle and each part of the mobile manipulator. In addition, to ensure the accurate placement of the end effector on the target point an attractive potential function is applied to the optimal control formulation. Next, a mixed analytical-numerical algorithm is proposed to generate the point-to-point optimal path. Finally, the proposed method is verified by a number of simulations on a two-link tricycle manipulator.

  20. 1,4-Benzodiazepine N-Nitrosoamidines: Useful Intermediates in the Synthesis of Tricyclic Benzodiazepines

    Directory of Open Access Journals (Sweden)

    Carlos del Pozo

    2006-08-01

    Full Text Available 1,4-Benzodiazepine N-nitrosoamidines have been used as scaffolds for the preparation of different tricyclic derivatives. Replacement of the N-nitrosoamidine moiety through treatment with the nucleophiles acetylhydrazine, aminoacetaldehyde dimethylacetal and 1-amino-2-propanol, followed by an acid-catalyzed cyclization step, afforded triazolo and imidazobenzodiazepines 1, 6, and 7, respectively, in good yields. When acetylhydrazine is used as a nucleophile, the overall process provides an alternative route to alprazolam (1b and triazolam (1c, respectively.

  1. Vinylogous Nicholas reactions in the synthesis of bi- and tricyclic cycloheptynedicobalt complexes.

    Science.gov (United States)

    Kolodziej, Izabela; Green, James R

    2015-11-28

    The Lewis acid mediated intramolecular Nicholas reactions of allylic acetate enyne-Co2(CO)6 complexes afford cycloheptenyne-Co2(CO)6 complexes in three manifestations. Electron rich aryl substituted alkyne complexes give tricyclic 6,7,x-benzocycloheptenyne complexes, with x = 5, 6, or 7. Allylsilane substituted complexes afford exo methylene bicyclic x,7-cycloheptenyne complexes (x = 6,7). The allyl acetate function may also be replaced by a benzylic acetate, to afford dibenzocycloheptyne-Co2(CO)6 complexes. Following reductive complexation, the methodology may be applied to the synthesis of the icetexane diterpene carbon framework.

  2. The effects of tricyclic and 'atypical' antidepressants on spontaneous locomotor activity in rodents.

    Science.gov (United States)

    Tucker, J C; File, S E

    1986-01-01

    With the exception of amineptin, buproprion and nomifensine all tricyclic and 'atypical' antidepressants have been reported to reduce spontaneous motor activity in rodents, after both acute and chronic administration. However, with the diversity of chemical actions of these drugs it is unlikely that a single neurochemical mechanism is underlying this one behavioral effect. These widespread sedative effects have implications for interpreting behavioral changes in other test situations, since sedation generally occurs at doses that fall within the dose-range effective in other tests. We also review the effects on spontaneous motor activity of withdrawal from chronic antidepressant treatment.

  3. Synthesis of some new tricyclic 4(3H)-quinazolinone derivatives.

    Science.gov (United States)

    Jafari, E; Khodarahmi, G A; Hakimelahi, G H; Tsai, F Y; Hassanzadeh, F

    2011-07-01

    Quinazolinones are interesting molecules with a wide range of biological activities. We prepared a number of quinazolinone derivatives by the condensation of 5-bromo- or 5-nitro-substituted anthranilic acids with chloro-acyl chlorides. Anthranilic acid derivatives were treated with either 3-chloro-propionyl chloride or 4-chloro-butyryl chloride to yield the corresponding N-acyl-anthranilic acids. The resultants were reacted with acetic anhydride to afford the benzoxazinone intermediates, which upon condensation with elected amines in either DMF or ethanol gave the corresponding tricyclic 4(3H)-quinazolinone derivatives. It was found that reactions in DMF produced higher yields.

  4. Graphenes–Aromatic Giants

    Indian Academy of Sciences (India)

    Graphenes - Aromatic Giants. Ivan Gutman Boris Furtula. Volume 16 Issue 12 December 2011 pp 1238-1245. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/016/12/1238-1245. Keywords. Graphenes; polycyclic aromatic hydrocarbons; polyphenyls; condensed benzenes.

  5. Not all side effects associated with tricyclic antidepressant therapy are true side effects.

    Science.gov (United States)

    Thiwan, Syed; Drossman, Douglas A; Morris, Carolyn B; Dalton, Chris; Toner, Brenda B; Diamant, Nicholas E; Hu, J B; Whitehead, William E; Leserman, Jane; Bangdiwala, Shrikant I

    2009-04-01

    Patients with functional gastrointestinal disorders treated with tricyclic antidepressants sometimes report nongastrointestinal symptoms; it is unclear whether these are drug side effects or reflect a behavioral tendency to report symptoms. We evaluated whether symptoms reported before treatment with a tricyclic antidepressant (desipramine) increased in number or worsened in severity after 2 weeks of treatment and assessed the baseline factors that predispose patients to report symptoms. Female patients in a multicenter National Institutes of Health trial for functional bowel disorders completed a 15-item symptom questionnaire at baseline (before randomization), 2 weeks after they were given desipramine (n = 81) or placebo (n = 40), and at study completion (12 weeks). Patients were asked about the severity and frequency of 15 symptoms. Results were analyzed from 57 patients given desipramine who completed the questionnaires. Symptoms reported as side effects to have occurred more frequently and also worsened at week 2 in the group given desipramine included dizziness, dry mouth/thirstiness, lightheadedness, jittery feelings/tremors, and flushing. Symptoms that did not change in severity or showed improvement at week 2 in the group given desipramine included morning tiredness, nausea, blurred vision, headaches, appetite reduction, and trouble sleeping. Psychologic distress but not desipramine blood level correlated with symptom reporting. Most symptoms often attributed to side effects of desipramine were present before treatment; only a few, related to anticholinergic effects, worsened 2 weeks after treatment, suggesting that most so-called side effects were not associated specifically with desipramine use. Such symptoms might instead be associated with psychologic distress.

  6. Scaffold-hopping from xanthines to tricyclic guanines: A case study of dipeptidyl peptidase 4 (DPP4) inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Pissarnitski, Dmitri A.; Zhao, Zhiqiang; Cole, David; Wu, Wen-Lian; Domalski, Martin; Clader, John W.; Scapin, Giovanna; Voigt, Johannes; Soriano, Aileen; Kelly, Theresa; Powles, Mary Ann; Yao, Zuliang; Burnett, Duane A. (Merck)

    2016-11-01

    Molecular modeling of unbound tricyclic guanine scaffolds indicated that they can serve as effective bioisosteric replacements of xanthines. This notion was further confirmed by a combination of X-ray crystallography and SAR studies, indicating that tricyclic guanine DPP4 inhibitors mimic the binding mode of xanthine inhibitors, exemplified by linagliptin. Realization of the bioisosteric relationship between these scaffolds potentially will lead to a wider application of cyclic guanines as xanthine replacements in drug discovery programs for a variety of biological targets. Newly designed DPP4 inhibitors achieved sub-nanomolar potency range and demonstrated oral activity in vivo in mouse glucose tolerance test.

  7. Platelet alpha 2-adrenergic receptors in major depressive disorder. Binding of tritiated clonidine before and after tricyclic antidepressant drug treatment

    International Nuclear Information System (INIS)

    Garcia-Sevilla, J.A.; Zis, A.P.; Hollingsworth, P.J.; Greden, J.F.; Smith, C.B.

    1981-01-01

    The specific binding of tritiated (3H)-clonidine, an alpha 2-adrenergic receptor agonist, to platelet membranes was measured in normal subjects and in patients with major depressive disorder. The number of platelet alpha 2-adrenergic receptors from the depressed group was significantly higher than that found in platelets obtained from the control population. Treatment with tricyclic antidepressant drugs led to significant decreases in the number of platelet alpha 2-adrenergic receptors. These results support the hypothesis that the depressive syndrome is related to an alpha 2-adrenergic receptor supersensitivity and that the clinical effectiveness of tricyclic antidepressant drugs is associated with a decrease in the number of these receptors

  8. Synthesis of Quaternary Ammonium Salts of Tricyclic Cationic Drugs: A One-Pot Synthesis for the Bioorganic Chemistry Laboratory

    Science.gov (United States)

    Brunauer, Linda S.; Mogannam, Abid C.; Hwee, Won B.; Chen, James Y.

    2007-01-01

    A one-pot conversion of tricyclic cationic drugs to their quaternary ammonium forms is described for a widely used bioactive drug: chlorpromazine, a phenothiazine-based antipsychotic. After conversion to its free base, the parent drug was methylated using substoichiometric amounts of methyl iodide dissolved in ether; the charged quaternary…

  9. [Cappuccino coffee treatment of xerostomia in patients taking tricyclic antidepressants: preliminary report].

    Science.gov (United States)

    Chodorowski, Zygmunt

    2002-01-01

    10 patients underwent a trial treatment with Cappuccino coffee. All of them (8 university lecturers and 2 clerks) aged from 60 to 69 (average 63) years old, used tricyclic antidepressant because of insomnia as a monosymptomatic type of depression or insomnia as a dominant symptom in the course of depression. One, evening dose of doxepine was from 150 to 250 (average 225) mg, causing xerostomia next day usually between 9-15 o'clock. The five-minute--chewing of 15.0 g of Cappuccino coffee increased the amount of saliva, decreased xerostomia and improved the ability of speech. Beneficial effect of coffee lasted from 0.5 to 4 (average about 2) hours. To the best of our knowledge there are no publications dealing with the positive effect of coffee in xerostomia.

  10. Synthesis, antimicrobial, DNA cleavage and antioxidant activities of tricyclic sultams derived from saccharin.

    Science.gov (United States)

    Elghamry, Ibrahim; Youssef, Magdy M; Al-Omair, Mohammed A; Elsawy, Hany

    2017-10-20

    Two series of fused tricyclic sultams (carboxylates, 3a, b and 5a, f, g and anilides 5b-e) were synthesized from saccharin and their chemical structures were confirmed by spectroscopic tools. Then, their antibacterial activities and MIC were evaluated against two strains of gram positive and gram-negative bacteria. The MIC values of the tested compounds are in the of range 8-33 μg/ml. In addition, their DNA cleavage ability, binding affinity and their anticancer activities against hepatic cancer cell were tested. And their antioxidant activities were also measured. Four carboxylate derivatives (3a, 5a, 5f and 5g) and one anilide (5d) of the tested compounds proved to be the highest activity all over the study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. Novel tricyclic-alpha-alkyloxyphenylpropionic acids: dual PPARalpha/gamma agonists with hypolipidemic and antidiabetic activity.

    Science.gov (United States)

    Sauerberg, Per; Pettersson, Ingrid; Jeppesen, Lone; Bury, Paul S; Mogensen, John P; Wassermann, Karsten; Brand, Christian L; Sturis, Jeppe; Wöldike, Helle F; Fleckner, Jan; Andersen, Anne-Sofie T; Mortensen, Steen B; Svensson, L Anders; Rasmussen, Hanne B; Lehmann, Søren V; Polivka, Zdenek; Sindelar, Karel; Panajotova, Vladimira; Ynddal, Lars; Wulff, Erik M

    2002-02-14

    Synthesis and structure-activity relationships of tricyclic alpha-ethoxy-phenylpropionic acid derivatives guided by in vitro PPARalpha and PPARgamma transactivation data and computer modeling led to the identification of the novel carbazole analogue, 3q, with dual PPARalpha (EC(50) = 0.36 microM) and PPARgamma (EC(50) = 0.17 microM) activity in vitro. Ten days treatment of db/db mice with 3q improved the insulin sensitivity, as measured by OGTT, better than that seen with both pioglitazone and rosiglitazone treatment, suggesting in vivo PPARgamma activity. Likewise, 3q lowered plasma triglycerides and cholesterol in high cholesterol fed rats after 4 days treatment, indicating in vivo PPARalpha activity. Investigations of the pharmacokinetics of selected compounds suggested that extended drug exposure improved the in vivo activity of in vitro active compounds.

  12. Pro-aromatic and anti-aromatic π-conjugated molecules: an irresistible wish to be diradicals

    KAUST Repository

    Zeng, Zebing

    2015-01-01

    © 2015 The Royal Society of Chemistry. Aromaticity is an important concept to understand the stability and physical properties of π-conjugated molecules. Recent studies on pro-aromatic and anti-aromatic molecules revealed their irresistible tendency to become diradicals in the ground state. Diradical character thus becomes another very important concept and it is fundamentally correlated to the physical (optical, electronic and magnetic) properties and chemical reactivity of most of the organic optoelectronic materials. Molecules with distinctive diradical character show unique properties which are very different from those of traditional closed-shell π-conjugated systems, and thus they have many potential applications in organic electronics, spintronics, non-linear optics and energy storage. This critical review first introduces the fundamental electronic structure of Kekulé diradicals within the concepts of anti-aromaticity and pro-aromaticity in the context of Hückel aromaticity and diradical character. Then recent research studies on various stable/persistent diradicaloids based on pro-aromatic and anti-aromatic compounds are summarized and discussed with regard to their synthetic chemistry, physical properties, structure-property relationships and potential material applications. A summary and personal perspective is given at the end.

  13. Stable isotopes

    International Nuclear Information System (INIS)

    Evans, D.K.

    1986-01-01

    Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

  14. Superconductivity in aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Kubozono, Yoshihiro, E-mail: kubozono@cc.okayama-u.ac.jp [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Japan Science and Technology Agency, ACT-C, Kawaguchi 332-0012 (Japan); Goto, Hidenori; Jabuchi, Taihei [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Yokoya, Takayoshi [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Kambe, Takashi [Department of Physics, Okayama University, Okayama 700-8530 (Japan); Sakai, Yusuke; Izumi, Masanari; Zheng, Lu; Hamao, Shino; Nguyen, Huyen L.T. [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Sakata, Masafumi; Kagayama, Tomoko; Shimizu, Katsuya [Center of Science and Technology under Extreme Conditions, Osaka University, Osaka 560-8531 (Japan)

    2015-07-15

    Highlights: • Aromatic superconductor is one of core research subjects in superconductivity. Superconductivity is observed in certain metal-doped aromatic hydrocarbons. Some serious problems to be solved exist for future advancement of the research. This article shows the present status of aromatic superconductors. - Abstract: ‘Aromatic hydrocarbon’ implies an organic molecule that satisfies the (4n + 2) π-electron rule and consists of benzene rings. Doping solid aromatic hydrocarbons with metals provides the superconductivity. The first discovery of such superconductivity was made for K-doped picene (K{sub x}picene, five benzene rings). Its superconducting transition temperatures (T{sub c}’s) were 7 and 18 K. Recently, we found a new superconducting K{sub x}picene phase with a T{sub c} as high as 14 K, so we now know that K{sub x}picene possesses multiple superconducting phases. Besides K{sub x}picene, we discovered new superconductors such as Rb{sub x}picene and Ca{sub x}picene. A most serious problem is that the shielding fraction is ⩽15% for K{sub x}picene and Rb{sub x}picene, and it is often ∼1% for other superconductors. Such low shielding fractions have made it difficult to determine the crystal structures of superconducting phases. Nevertheless, many research groups have expended a great deal of effort to make high quality hydrocarbon superconductors in the five years since the discovery of hydrocarbon superconductivity. At the present stage, superconductivity is observed in certain metal-doped aromatic hydrocarbons (picene, phenanthrene and dibenzopentacene), but the shielding fraction remains stubbornly low. The highest priority research area is to prepare aromatic superconductors with a high superconducting volume-fraction. Despite these difficulties, aromatic superconductivity is still a core research target and presents interesting and potentially breakthrough challenges, such as the positive pressure dependence of T{sub c} that is clearly

  15. Strong CH/O interactions between polycyclic aromatic hydrocarbons and water: Influence of aromatic system size.

    Science.gov (United States)

    Veljković, Dušan Ž

    2018-03-01

    Energies of CH/O interactions between water molecule and polycyclic aromatic hydrocarbons with a different number of aromatic rings were calculated using ab initio calculations at MP2/cc-PVTZ level. Results show that an additional aromatic ring in structure of polycyclic aromatic hydrocarbons significantly strengthens CH/O interactions. Calculated interaction energies in optimized structures of the most stable tetracene/water complex is -2.27 kcal/mol, anthracene/water is -2.13 kcal/mol and naphthalene/water is -1.97 kcal/mol. These interactions are stronger than CH/O contacts in benzene/water complex (-1.44 kcal/mol) while CH/O contacts in tetracene/water complex are even stronger than CH/O contacts in pyridine/water complexes (-2.21 kcal/mol). Electrostatic potential maps for different polycyclic aromatic hydrocarbons were calculated and used to explain trends in the energies of interactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Electron delocalization and aromaticity in low-lying excited states of archetypal organic compounds.

    Science.gov (United States)

    Feixas, Ferran; Vandenbussche, Jelle; Bultinck, Patrick; Matito, Eduard; Solà, Miquel

    2011-12-14

    Aromaticity is a property usually linked to the ground state of stable molecules. Although it is well-known that certain excited states are unquestionably aromatic, the aromaticity of excited states remains rather unexplored. To move one step forward in the comprehension of aromaticity in excited states, in this work we analyze the electron delocalization and aromaticity of a series of low-lying excited states of cyclobutadiene, benzene, and cyclooctatetraene with different multiplicities at the CASSCF level by means of electron delocalization measures. While our results are in agreement with Baird's rule for the aromaticity of the lowest-lying triplet excited state in annulenes having 4nπ-electrons, they do not support Soncini and Fowler's generalization of Baird's rule pointing out that the lowest-lying quintet state of benzene and septet state of cyclooctatetraene are not aromatic.

  17. Determination of the tricyclic antidepressants amitriptyline, nortriptyline, imipramine, desipramine, clomipramine and desmethylclomipramine in dried blood spots using LC-MS/MS

    NARCIS (Netherlands)

    Berm, E.J.J.; Paardekooper, J.; Brummel-Mulder, E.; Hak, E.; Wilffert, B.; Maring, J.G.

    2013-01-01

    Background: Therapeutic Drug Monitoring (TDM) of Tricyclic Antidepressants (TADs) is considered useful in patients with major depressive disorders, since these drugs display large individual differences in clearance and therapeutic windows of these drugs are relatively small. We developed an assay

  18. On Benzene and Aromaticity

    Indian Academy of Sciences (India)

    intuition, deduction and simple experimentation also need to be retold. The creativity of scientists has an appeal that transcends the subject. Chemistry of aromatic compounds provides ample opportunities for the teacher to cover many of the above aspects. One can move from almost trivial questions to those that require ...

  19. On Benzene and Aromaticity

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 4. On Benzene and Aromaticity History and Some Folklore. M V Bhatt. General Article Volume 3 Issue 4 April 1998 pp 88-93. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/003/04/0088-0093 ...

  20. Graphenes – Aromatic Giants

    Indian Academy of Sciences (India)

    Srimath

    Polycyclic aromatic hydrocarbons (often abbreviated as PAH) are an important class of organic compounds. Students learn about them in any course on organic chemistry. The best known representatives are benzene (which, in fact, is cyclic, not polycy- clic), naphthalene, anthracene, phenanthrene and pyrene. Today.

  1. Chronic Pain Treatment: The Influence of Tricyclic Antidepressants on Serotonin Release and Uptake in Mast Cells

    Directory of Open Access Journals (Sweden)

    Ilonka Ferjan

    2013-01-01

    Full Text Available The involvement of serotonin (5-HT in chronic pain mechanisms is established. 5-HT inhibits central painful stimuli, but recent data suggests that 5-HT could also enhance pain stimulus from the periphery, where mast cells play an important role. We aimed in our study to clarify the influence of selected tricyclic antidepressants (TCAs on mast cell function: secretion, uptake, and reuptake of 5-HT, that could interfere with 5-HT levels and in this way contribute to the generation of pain. As an experimental model, we used isolated rat peritoneal mast cells and incubated them with selected TCAs (clomipramine, amitriptyline, doxepin, and imipramine under different experimental conditions. 5-HT release, uptake, and reuptake were determined spectrofluorometrically. We showed that TCAs were able to inhibit 5-HT secretion from mast cells, as well as uptake of exogenous 5-HT and reuptake of secreted 5-HT back into mast cells. The effects of TCAs were concentration dependent; higher concentrations of TCAs inhibited the secretion of 5-HT induced by compound 48/80, whereas lower concentrations of TCAs inhibited 5-HT uptake. The most effective TCA was halogenated clomipramine. As TCAs are well introduced in chronic pain treatment, the insight into mechanisms of action is important for an understanding of their effect in various pain conditions.

  2. Impending cardiogenic shock due to tricyclic antidepressant toxicity, computed tomography findings: a case report

    Directory of Open Access Journals (Sweden)

    Mohammad Ghasem Hanafi

    2016-08-01

    Full Text Available A computed tomographic (CT with contrast enhancement is extensively used for assessment of a wide range of thoracic and abdominal circumstances. Thus, as the use of CT in the evaluation of unstable patients increases, the chance to see the CT features of imminent cardiogenic shock and cardiac arrest also increases during scanning. The patient was a 27 year old man who brought to the emergency department by paramedics unresponsive, After physical examination and obtaining ECG due to presence of hypotension ,with suspicion to traumatic injury, Thoracoabdominal CT was done for patient which show dense opacification of the right hepatic lobe, that resembling contrast extravasations from IVC and the hepatic vein, laparatmy was done for patient which were normal .Patient Has developed cardiac arrest and died at the end of surgery. Postmortem autopsy and toxicology revealed Tricyclic antidepressant intoxication as a cause of cardiac arrest and death. TCA poisoned Patients may have normal ECG findings on arrival. In spite of infrequent reports of cardiogenic shock that occurring during CT scan, knowledge of distinctive CT findings of these patients is very essential for precise analysis of images, in addition to informing clinical physician for malpractice avoidance and immediate initiation of resuscitation.

  3. Photodissociation of aromatic azides

    Science.gov (United States)

    Budyka, M. F.

    2008-08-01

    Quantitative data on the photochemical activity of aromatic azides and on the mechanism and kinetics of azido group photodissociation are analysed and described systematically for the first time. The results of quantum chemical calculations of the azide structure in the ground and lower electronically excited states and the potential energy surfaces along the reaction coordinate of the N-N2 bond dissociation are considered.

  4. Aromatics oxidation and soot formation in flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T. [Massachusetts Institute of Technology, Cambridge (United States)

    1993-12-01

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify and to determine or confirm rate constants for the main benzene oxidation reactions in flames, and to characterize fullerenes and their formation mechanisms and kinetics.

  5. Tricyclic coumarin sulphonate derivatives with alkaline phosphatase inhibitory effects: in vitro and docking studies.

    Science.gov (United States)

    Iqbal, Jamshed; El-Gamal, Mohammed I; Ejaz, Syeda Abida; Lecka, Joanna; Sévigny, Jean; Oh, Chang-Hyun

    2018-12-01

    Tissue-nonspecific alkaline phosphatase (TNAP) is an important isozyme of alkaline phosphatases, which plays different pivotal roles within the human body. Most importantly, it is responsible for maintaining the balanced ratio of phosphate and inorganic pyrophosphate, thus regulates the extracellular matrix calcification during bone formation and growth. The elevated level of TNAP has been linked to vascular calcification and end-stage renal diseases. Consequently, there is a need to search for highly potent and selective inhibitors of alkaline phosphatases (APs) for treatment of disorders associated with the over-expression of APs. Herein, a series of tricyclic coumarin sulphonate 1a-za with known antiproliferative activity, was evaluated for AP inhibition against human tissue nonspecific alkaline phosphatase (h-TNAP) and human intestinal alkaline phosphatase (h-IAP). The methylbenzenesulphonate derivative 1f (IC 50  = 0.38 ± 0.01 μM) was found to be the most active h-TNAP inhibitor. Another 4-fluorobenzenesulphonate derivative 1i (IC 50  = 0.45 ± 0.02 μM) was found as the strongest inhibitor of h-IAP. Some of the derivatives were also identified as highly selective inhibitors of APs. Detailed structure-activity relationship (SAR) was investigated to identify the functional groups responsible for the effective inhibition of AP isozymes. The study was also supported by the docking studies to rationalise the most possible binding site interactions of the identified inhibitors with the targeted enzymes.

  6. Complexation studies of cyclodextrins with tricyclic antidepressants using ion-selective electrodes.

    Science.gov (United States)

    Valsami, G N; Koupparis, M A; Macheras, P E

    1992-01-01

    The complexation of six tricyclic antidepressant drugs [amitriptylin (AMN), nortriptylin (NRN), imipramin (IMN), doxepin (DXN), protriptylin (PTN), and maprotilin (MPN)] with alpha- and beta-cyclodextrins (CDs) using ion-selective electrodes (ISEs) as drug ion sensors is described. Binding parameters were calculated by nonlinear fitting of the model described by the Scatchard equation, to the experimental data of a titration of a CD solution with the ion of interest. One binding site (the CD cavity) was found in all cases with both CDs. The calculated association constants at 25 degrees C using CD concentrations in the range of 0.0100-0.0010 M, varied from 4.81 x 10(3) M-1 (MPN) to 23.9 x 10(3) M-1 (AMN) in the case of beta-CD and from 50 M-1 (DXN) to 123 M-1 (MPN) in the case of alpha-CD. The precision for the estimation of the binding parameters was 0.1-5.0% (within-run RSD%) and 8-10% (between-run RSD%; n = 3). The complexation of the drugs with beta-CD was also examined as a function of temperature in the range of 5-37 degrees C; it was found to decrease by increasing temperature. Van't Hoff analysis gave good correlations (r greater than or equal to 0.989) for all drug ions studied. The estimates of the thermodynamic parameters indicate that the formation of inclusion complexes is enthalpy driven. A compensation plot based on the thermodynamic parameters delta H and delta S resulted in a linear relationship, which is indicative of a common type of force involved in the complexation of drugs to beta-CD.

  7. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1994-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets, with a few more additions - with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers - exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the foree of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc. (orig.)

  8. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1993-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

  9. Contorted polycyclic aromatics.

    Science.gov (United States)

    Ball, Melissa; Zhong, Yu; Wu, Ying; Schenck, Christine; Ng, Fay; Steigerwald, Michael; Xiao, Shengxiong; Nuckolls, Colin

    2015-02-17

    CONSPECTUS: This Account describes a body of research in the design, synthesis, and assembly of molecular materials made from strained polycyclic aromatic molecules. The strain in the molecular subunits severely distorts the aromatic molecules away from planarity. We coined the term "contorted aromatics" to describe this class of molecules. Using these molecules, we demonstrate that the curved pi-surfaces are useful as subunits to make self-assembled electronic materials. We have created and continue to study two broad classes of these "contorted aromatics": discs and ribbons. The figure that accompanies this conspectus displays the three-dimensional surfaces of a selection of these "contorted aromatics". The disc-shaped contorted molecules have well-defined conformations that create concave pi-surfaces. When these disc-shaped molecules are substituted with hydrocarbon side chains, they self-assemble into columnar superstructures. Depending on the hydrocarbon substitution, they form either liquid crystalline films or macroscopic cables. In both cases, the columnar structures are photoconductive and form p-type, hole- transporting materials in field effect transistor devices. This columnar motif is robust, allowing us to form monolayers of these columns attached to the surface of dielectrics such as silicon oxide. We use ultrathin point contacts made from individual single-walled carbon nanotubes that are separated by a few nanometers to probe the electronic properties of short stacks of a few contorted discs. We find that these materials have high mobility and can sense electron-deficient aromatic molecules. The concave surfaces of these disc-shaped contorted molecules form ideal receptors for the molecular recognition and assembly with spherical molecules such as fullerenes. These interfaces resemble ball-and-socket joints, where the fullerene nests itself in the concave surface of the contorted disc. The tightness of the binding between the two partners can be

  10. Aromatic molecules as spintronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, J. H., E-mail: judith.ojeda@uptc.edu.co [Instituto de Alta investigación, Universidad de Tarapacá, Casilla 7D Arica (Chile); Grupo de Física de Materiales, Universidad Pedagógica y Tecnológica de Colombia, Tunja (Colombia); Orellana, P. A. [Departamento de Física, Universidad Técnica Federico Santa María, Casilla 110-V, Valparaíso (Chile); Laroze, D. [Instituto de Alta investigación, Universidad de Tarapacá, Casilla 7D Arica (Chile)

    2014-03-14

    In this paper, we study the spin-dependent electron transport through aromatic molecular chains attached to two semi-infinite leads. We model this system taking into account different geometrical configurations which are all characterized by a tight binding Hamiltonian. Based on the Green's function approach with a Landauer formalism, we find spin-dependent transport in short aromatic molecules by applying external magnetic fields. Additionally, we find that the magnetoresistance of aromatic molecules can reach different values, which are dependent on the variations in the applied magnetic field, length of the molecules, and the interactions between the contacts and the aromatic molecule.

  11. Stable Organic Neutral Diradical via Reversible Coordination.

    Science.gov (United States)

    Lu, Zhenpin; Quanz, Henrik; Burghaus, Olaf; Hofmann, Jonas; Logemann, Christian; Beeck, Sebastian; Schreiner, Peter R; Wegner, Hermann A

    2017-12-27

    We report the formation of a stable neutral diboron diradical simply by coordination of an aromatic dinitrogen compound to an ortho-phenyldiborane. This process is reversible upon addition of pyridine. The diradical species is stable above 200 °C. Computations are consistent with an open-shell triplet diradical with a very small open-shell singlet-triplet energy gap that is indicative of the electronic disjointness of the two radical sites. This opens a new way of generating stable radicals with fascinating electronic properties useful for a large variety of applications.

  12. Discovery of Novel Tricyclic Heterocycles as Potent and Selective DPP-4 Inhibitors for the Treatment of Type 2 Diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wen-Lian; Hao, Jinsong; Domalski, Martin; Burnett, Duane A.; Pissarnitski, Dmitri; Zhao, Zhiqiang; Stamford, Andrew; Scapin, Giovanna; Gao, Ying-Duo; Soriano, Aileen; Kelly, Terri M.; Yao, Zuliang; Powles, Mary Ann; Chen, Shiying; Mei, Hong; Hwa, Joyce (Merck)

    2016-05-12

    In our efforts to develop second generation DPP-4 inhibitors, we endeavored to identify distinct structures with long-acting (once weekly) potential. Taking advantage of X-ray cocrystal structures of sitagliptin and other DPP-4 inhibitors, such as alogliptin and linagliptin bound to DPP-4, and aided by molecular modeling, we designed several series of heterocyclic compounds as initial targets. During their synthesis, an unexpected chemical transformation provided a novel tricyclic scaffold that was beyond our original design. Capitalizing on this serendipitous discovery, we have elaborated this scaffold into a very potent and selective DPP-4 inhibitor lead series, as highlighted by compound 17c.

  13. Organic anion and cation transport in vitro by dog choroid plexus: Effects of neuroleptics and tricyclic antidepressants

    International Nuclear Information System (INIS)

    Barany, E.H.

    1979-01-01

    Dog lateral choroid plexus accumulates the cation 14 C-emepronium and the divalent anion 125 I-iodipamide in vitro. At 10 μM, high potency neuroleptics with a substituted piperazine side chain and also haloperidol depress only the uptake of the cation and even stimulate the uptake of the anion. In contrast, at 1-10μM, the accumulation of both test substances is inhibited by neuroleptics and tricyclic antidepresssants with an aliphatic side chain. Such unspecific effects on seemingly unrelated transport systems at concentrations reached clinically in the CSF might explain some side actions of low potency neuroleptics and antidepressants. (author)

  14. Direct and Indirect Drug Design Approaches for the Development of Novel Tricyclic Antipsychotics: Potential 5-HT2A Antagonist

    Directory of Open Access Journals (Sweden)

    Mahantesh Namdev Jadhav

    2013-01-01

    Full Text Available Schizophrenia is a mental disorder manifested largely by disintegration of thought processes and emotional responsiveness. Given the therapeutic and toxic limitations of clinically available drugs, it is clear that there is still a need for the development of new generation antipsychotic agents with an improved clinical profile. Development of novel hybrid atypical tricyclic antipsychotic pharmacophore was achieved using direct (by measuring docking score of designed molecules on modelled 5- receptor and indirect (current, clinically available therapeutic agents’ data drug design approaches.

  15. A pilot pharmacokinetic study of tricyclic antidepressant ovine Fab for TCA poisoning in children.

    Science.gov (United States)

    Yalindağ-Oztürk, Nilüfer; Goto, Collin S; Shepherd, Greene; Torres, Olivia Nayeli; Giroir, Brett

    2010-06-01

    A pilot study of tricyclic antidepressant (TCA)-specific antibody fragments (TCA Fab) in TCA-intoxicated adults showed a marked increase in serum total TCA concentrations following TCA Fab infusion with no worsening signs of TCA toxicity. TCA Fab pharmacokinetics (PK) was not described in this adult study. The objective of this study was to evaluate the PK of TCA Fab in children with TCA poisoning. This was an open-label, single-center, dose escalation pilot trial of three patients. Inclusion criteria were documented TCA ingestion with at least one serious complication (QRS prolongation, dysrhythmia, hypotension, seizure, or coma). Patients were assigned to either a low-dose intravenous TCA Fab regimen (15, 30, and 60 mg/kg) or a high-dose regimen (30, 60, and 120 mg/kg) as needed to reverse TCA toxicity. Following the administration of TCA Fab, samples of blood and urine were obtained for PK evaluations. The outcomes of interest were serum and urine TCA concentrations (free and total), serum and urine Fab concentrations, improvement or worsening of TCA toxicity, and adverse effects. Three study patients were 11, 11, and 14 years of age. Two patients received 15 mg/kg of TCA Fab and one patient received a total of 90 mg/kg of TCA Fab (30 + 60 mg/kg). Serum-bound TCA increased significantly following TCA Fab administration with concomitant enhanced urinary elimination. Serum-free TCA concentrations were minimal to undetectable. Fab data were available for two patients. The serum TCA Fab area under the curve was 306.12 mg/L/h for the 15 mg/kg dose and 2,198.10 mg/L/h for the 90 mg/kg dose of TCA Fab. Maximum Fab concentrations correlated with maximum bound TCA in serum. The volume of distribution (V(D)) of TCA Fab was 0.2-0.3 L/kg. The clearance was 0.036-0.05 L/kg/h and the elimination half-life was 4 h. No adverse effects were observed. The limited PK data from this study are consistent with binding of TCA to TCA Fab and redistribution of TCA from the tissue to

  16. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  17. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

  18. Applying quantitative structure-activity relationship (QSAR) methodology for modeling postmortem redistribution of benzodiazepines and tricyclic antidepressants.

    Science.gov (United States)

    Giaginis, Constantinos; Tsantili-Kakoulidou, Anna; Theocharis, Stamatios

    2014-06-01

    Postmortem redistribution (PMR) constitutes a multifaceted process, which complicates the interpretation of drug concentrations by forensic toxicologists. The present study aimed to apply quantitative structure-activity relationship (QSAR) analysis for modeling PMR data of structurally related drugs, 10 benzodiazepines and 10 tricyclic antidepressants. For benzodiazepines, an adequate QSAR model was obtained (R(2) = 0.98, Q(2) = 0.88, RMSEE = 0.12), in which energy, ionization and molecular size exerted significant impact. For tricyclic antidepressants, an adequate QSAR model with slightly inferior statistics (R(2) = 0.95, Q(2) = 0.87, RMSEE = 0.29) was established after exclusion of maprotiline, in which energy parameters, basicity character and lipophilicity exerted significant contribution. Thus, QSAR analysis could be used as a complementary tool to provide an informative illustration of the contributing molecular, physicochemical and structural properties in PMR process. However, the complexity, non-static and time-dependent nature of PMR endpoints raises serious concerns whether QSAR methodology could predict the degree of redistribution, highlighting the need for animal-derived PMR data.

  19. The Comparison of Efficacy of Tricyclic Antidepressant with and without Non Steroidal Anti Inflammatory Drugs in Chronic Low Back Pain

    Directory of Open Access Journals (Sweden)

    A.R. Yavarikia

    2007-07-01

    Full Text Available Introduction & Objectives: Low back pain (LBP is one of common medical problems with several accepted medical modalities such as drugs, physiotherapy, surgery, etc. We studied the efficacy of tricyclic antidepressant (TCA, and tricyclic antidepressant plus non steroidal anti inflammatory drugs (TCA + NSAID in 200 patients with chronic LBP. Materials & Methods: In an experimental clinical trial study on patients with chronic low back pain without organic findings, patients were divided in two groups of 100 cases. At certain times the response to treatment protocols were collected and compared using VAS system. Patient’s data including age, sex, smoking and response to treatment were recorded and analyzed using chi-square, t-tests, ANOVA and SPSS software. Results: 83 (41.5% of patients were males and 117 (58.5% were females. The age range was 21 to 75 (mean age 43.1 14.1y there was no meaning full statistical difference in demographic characteristics such as age, sex (respectively p=0.66, p=0.78 the ultimate pain was less (p0.05.Conclusion: TCA prescription is an efficient method of treatment of low back pain with or with out NSAIDS. But using NSAID+TCA will be almost more powerful and efficient method in the long term period.

  20. Docking Based 3D-QSAR Study of Tricyclic Guanidine Analogues of Batzelladine K as anti-malarial agents

    Science.gov (United States)

    Ahmed, Nafees; Anwar, Sirajudheen; Thet Htar, Thet

    2017-06-01

    The Plasmodium falciparum Lactate Dehydrogenase enzyme (PfLDH) catalyzes inter-conversion of pyruvate to lactate during glycolysis producing the energy required for parasitic growth. The PfLDH has been studied as a potential molecular target for development of anti-malarial agents. In an attempt to find the potent inhibitor of PfLDH, we have used Discovery studio to perform molecular docking in the active binding pocket of PfLDH by CDOCKER, followed by three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of tricyclic guanidine batzelladine compounds, which were previously synthesized in our laboratory. Docking studies showed that there is a very strong correlation between in silico and in vitro results. Based on docking results, a highly predictive 3D-QSAR model was developed with q2 of 0.516. The model has predicted r2 of 0.91 showing that predicted IC50 values are in good agreement with experimental IC50 values. The results obtained from this study revealed the developed model can be used to design new anti-malarial compounds based on tricyclic guanidine derivatives and to predict activities of new inhibitors.

  1. Quality of the paratransit service (tricycle and its operation in Aba, Nigeria: An analysis of customers' opinions

    Directory of Open Access Journals (Sweden)

    Obioma R. Nwaogbe

    2012-11-01

    Full Text Available This study examines the quality of the paratransit service and its operations in Aba, Abia State, Nigeria, with a view to identifying its challenges and contributions to informal transport and equitable service distribution to the residents of Aba. Structured questionnaires and past literature were used as sources of data. The primary data included road networks, number of trips per day by operators, operating speed, and purpose of travel, passengers' security, tricycle speed, and waiting time. The study was conducted by using two questionnaires: one for the operators and the other for tricycle users. The total number of completed questionnaires for the survey was 100 for operators and 229 for users. The sampling technique used was random sampling from several zones of the study area. Data were analysed using percentage and Chi-square statistical techniques for testing the hypotheses with the Minitab 11.0 version package. The study found that 92% of operators reported a high level of road network deterioration, and 61% reported making 9-12 trips per day. The hypothesis test was used to study people's feelings about the attributes of the service provided for paratransit users, such as affordability, regularity, comfort and safety. It was found that there is no significant difference at the 5% level between the various categories of these respondents.

  2. Advances towards aromatic oligoamide foldamers

    DEFF Research Database (Denmark)

    Hjelmgaard, Thomas; Plesner, Malene; Dissing, Mette Marie

    2014-01-01

    We have efficiently synthesized 36 arylopeptoid dimers with ortho-, meta-, and para-substituted aromatic backbones and tert-butyl or phenyl side chains. The dimers were synthesized by using a "submonomer method" on solid phase, by applying a simplified common set of reaction conditions. X-ray...... of the surrounding aromatic backbone. Investigation of the X-ray structures of two arylopeptoid dimers disclosed that the tert-butyl side chain invokes a cis amide conformation with a closely packed structure of the surrounding aromatic backbone while the phenyl side chain results in a trans amide conformation...

  3. Description of aromaticity in porphyrinoids.

    Science.gov (United States)

    Wu, Judy I; Fernández, Israel; Schleyer, Paul v R

    2013-01-09

    Like the larger nonplanar Möbius rings, porphyrinoid aromaticity is not due primarily to the macrocyclic π conjugation of the corresponding annulene perimeters. The block-localized wave function (BLW)-derived aromatic stabilization energies (ASE) of several porphyrinoids reveal that, on a per atom basis, the appended 6π electron heterocycles of porphyrinoids confer aromaticity much more effectively than the macrocyclic 4n+2 π electron conjugations. There is no direct relationship between thermochemical stability of porphyrinoids and their macrocyclic 4n or 4n+2 π electron counts. Porphyrinoids having an "antiaromatic" macrocyclic 4n+2 π electron conjugation pathway (e.g., 4) as well as those having no macrocyclic conjugation (e.g., 9) can be stabilized by aromaticity. Computed nucleus independent chemical shifts (NICS) and the anisotropy of the induced current density (ACID) disclose the intricate local versus macrocyclic circulation interplay for several porphyrinoids.

  4. A metal-catalyzed enyne-cyclization step for the synthesis of bi- and tricyclic scaffolds amenable to molecular library production

    DEFF Research Database (Denmark)

    Wu, Peng; Cohrt, Anders Emil O'Hanlon; Petersen, Rico

    2016-01-01

    A facile metal-catalyzed diversification step for the synthesis of novel bi- and tricyclic scaffolds from enyne substrates is reported in this study. From a single starting material, topologically diverse scaffolds for library synthesis can be generated and decorated in a few steps. The methodology...... was used to produce a library of 490 compounds within the European Lead Factory (ELF) Consortium....

  5. Bioassay of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Van Kirk, E.A.

    1980-08-01

    A positive relationship was found between the photodynamic activity of 24 polycyclic aromatic hydrocarbons versus published results on the mutagenicity, carcinogenicity, and initiation of unscheduled DNA synthesis. Metabolic activation of benzo(a)pyrene resulted in detection of increased mutagenesis in Paramecium tetraurelia as found also in the Ames Salmonella assay. The utility of P. tetraurelia as a biological detector of hazardous polycyclic aromatic hydrocarbons is discussed.

  6. Biosynthesis of bacterial aromatic polyketides.

    Science.gov (United States)

    Zhan, Jixun

    2009-01-01

    Aromatic polyketides represent important members of the family of polyketides, which have displayed a wide assortment of bioactive properties, such as antibacterial, antitumor, and antiviral activities. Bacterial aromatic polyketides are mainly synthesized by type II polyketide synthases (PKSs). Whereas malonyl-CoA is exclusively used as the extender unit, starter units can vary in different aromatic polyketide biosynthetic pathways, leading to a variety of polyketide backbones. Once the polyketide chains are elongated by the minimal PKSs to the full length, the immediate tailoring enzymes including ketoreductases, oxygenases and cyclases will work on the nascent chains to form aromatic structures, which will be further decorated by those late tailoring enzymes such as methyltransferases and glycosyltransferases. The mechanistic studies on the biosynthetic pathways of aromatic polyketides such as oxytetracycline and pradimicin A have been extensively carried out in recent years. Engineered biosynthesis of novel "unnatural" polyketides has been achieved in heterologous hosts such as Streptomyces coelicolor and Escherichia coli. This review covers the most recent advances in aromatic polyketide biosynthesis, which provide new enzymes or methods for building novel polyketide biosynthetic machinery.

  7. Stereoselective synthesis of tricyclic compounds by intramolecular palladium-catalyzed addition of aryl iodides to carbonyl groups

    Directory of Open Access Journals (Sweden)

    Jakub Saadi

    2016-06-01

    Full Text Available Starting from γ-ketoesters with an o-iodobenzyl group we studied a palladium-catalyzed cyclization process that stereoselectively led to bi- and tricyclic compounds in moderate to excellent yields. Four X-ray crystal structure analyses unequivocally defined the structure of crucial cyclization products. The relative configuration of the precursor compounds is essentially transferred to that of the products and the formed hydroxy group in the newly generated cyclohexane ring is consistently in trans-arrangement with respect to the methoxycarbonyl group. A transition-state model is proposed to explain the observed stereochemical outcome. This palladium-catalyzed Barbier-type reaction requires a reduction of palladium(II back to palladium(0 which is apparently achieved by the present triethylamine.

  8. Design and synthesis of tricyclic tetrahydroquinolines as a new series of nonsteroidal selective androgen receptor modulators (SARMs).

    Science.gov (United States)

    Nagata, Naoya; Miyakawa, Motonori; Amano, Seiji; Furuya, Kazuyuki; Yamamoto, Noriko; Inoguchi, Kiyoshi

    2011-03-15

    Some tricyclic tetrahydroquinolines (THQs) were found to have the potential of a new series of nonsteroidal selective androgen receptor modulators (SARMs). Compound 5b was first designed and synthesized under our hypothesis based on a four-point pharmacophoric requirement of the 3-carbonyl, 18-methyl, 17-hydroxyl, and 13-quaternary carbon groups of dihydrotestosterone (DHT). It was revealed that this compound exhibits not only a strong androgen receptor (AR) agonistic activity (EC(50)=9.2 nM) but also the highest selectivity in binding affinity to AR among the steroid hormone receptors. Furthermore, this compound showed a weak virilizing effect with retention of the desired anabolic effect as compared with DHT in vivo. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Roles of free radicals in type 1 phototherapeutic agents: aromatic amines, sulfenamides, and sulfenates.

    Science.gov (United States)

    Lin, Tien-Sung; Rajagopalan, Raghavan; Shen, Yuefei; Park, Sungho; Poreddy, Amruta R; Asmelash, Bethel; Karwa, Amolkumar S; Taylor, John-Stephen A

    2013-07-03

    Detailed analyses of the electron spin resonance (ESR) spectra, cell viability, and DNA degradation studies are presented for the photolyzed Type I phototherapeutic agents: aromatic amines, sulfenamides, and sulfenates. The ESR studies provided evidence that copious free radicals can be generated from these N-H, N-S, and S-O containing compounds upon photoirradiation with UV/visible light. The analyses of spectral data allowed us to identify the free radical species. The cell viability studies showed that these agents after exposure to light exert cytotoxicity to kill cancer cells (U937 leukemia cell lines HTC11, KB, and HT29 cell lines) in a dosage- and time-dependent manner. We examined a possible pathway of cell death via DNA degradation by a plasmid cleavage assay for several compounds. The effects of photosensitization with benzophenone in the presence of oxygen were examined. The studies indicate that planar tricyclic amines and sulfenamides tend to form π-electron delocalized aminyl radicals, whereas nonplanar ones tend to yield nitroxide radicals resulting from the recombination of aminyl radicals with oxygen. The ESR studies coupled with the results of cell viability measurements and DNA degradation reveal that planar N-centered radicals can provide higher potency in cell death and allow us to provide some insights on the reaction mechanisms. We also found the formation of azatropylium cations possessing high aromaticity derived from azepines can facilitate secondary electron transfer to form toxic O2(•-) radicals, which can further exert oxidative stress and cause cell death.

  10. A systematic review and meta-analysis of lithium augmentation of tricyclic and second generation antidepressants in major depression.

    Science.gov (United States)

    Nelson, J Craig; Baumann, Pierre; Delucchi, Kevin; Joffe, Russell; Katona, Cornelius

    2014-10-01

    Lithium augmentation of antidepressants for treatment of unipolar major depression was one of the first adjunctive strategies based on a neuropharmacologic rationale. Randomized controlled trials supported its efficacy but most trials added lithium to tricyclic antidepressants (TCAs). Despite its efficacy, use of lithium augmentation remains infrequent. The current systematic review and meta-analysis examines the efficacy of lithium augmentation as an adjunct to second generation antidepressants as well as to TCAs and considers reasons for its infrequent use. A systematic search of Medline and the Cochrane Clinical Trials database was performed. Randomized, placebo-controlled trials of lithium augmentation were selected. A fixed-effects meta-analysis was performed. Odds ratios for response were calculated for each treatment-control contrast, for the trials grouped by type of initial antidepressant (TCA or second generation antidepressant), and as a meta-analytic summary for all treatments combined. Nine trials that included 237 patients were selected. The odds ratio for response to lithium vs. placebo in all contrasts combined was 2.89 (95% CI 1.65, 5.05, z=3.72, p=0.0002). Heterogeneity was very low, I(2)=0%. Adjunctive lithium was effective with TCAs (7 contrasts) and with second generation agents (3 contrasts). Discontinuation due to adverse events was infrequent and did not differ between lithium and placebo. The meta-analysis is limited by the small size and number of trials and limited data for treatment resistant patients. Adjunctive lithium appears to be as effective for second generation antidepressants as it was for the tricyclics. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Rapid improvement of depressive symptoms in suicide attempters following treatment with milnacipran and tricyclic antidepressants – a case series

    Directory of Open Access Journals (Sweden)

    Kirino E

    2011-12-01

    Full Text Available Eiji Kirino, Masao GitohDepartment of Psychiatry, Juntendo University, School of Medicine, Shizuoka, JapanAbstract: Suicide is a serious social problem in many countries, including Japan. The majority of people who commit suicide suffer from depression. Suicide attempt patients suffering from serious physical injuries are initially treated in hospital emergency departments. The present post hoc analysis examined data from patients admitted to an emergency hospital for treatment of physical injuries, resulting from a suicide attempt, and initial psychiatric treatment for depression and prevention of future suicide attempts. The effects on depressive symptoms were studied in two groups of patients using the 17-item Hamilton depression scale (HAMD. One group (n = 6 had received intravenous tricyclic antidepressants (TCA (amitriptyline or clomipramine while the other group (n = 7 had been treated orally with milnacipran, a serotonin and norepinephrine reuptake inhibitor antidepressant. Prior to treatment the four highest scoring items on the HAMD scale were the same in both groups namely, item 1 (depressed mood, item 3 (suicidality, item 7 (interest in work and activities, and item 10 (psychic anxiety. After 1 week of treatment, mean global HAMD scores were significantly reduced in both groups. Treatment resulted in a significant reduction of five HAMD items in the TCA group, whereas in the milnacipran group 12 HAMD items were significantly reduced. Suicidality (item 3 was significantly improved by 1 week treatment with milnacipran, but not by TCAs. Milnacipran rapidly improved a wide range of depressive symptoms, including suicidality within the first week. The improvement with milnacipran would appear to be, at least, equivalent to that achieved with TCAs, possibly affecting a wider range of symptoms. Since milnacipran has been shown in comparative studies to be better tolerated than TCAs, this antidepressant offers an interesting option for the

  12. Naphthyridine-Benzoazaquinolone: Evaluation of a Tricyclic System for the Binding to (CAG)n Repeat DNA and RNA.

    Science.gov (United States)

    Li, Jinxing; Sakata, Akihiro; He, Hanping; Bai, Li-Ping; Murata, Asako; Dohno, Chikara; Nakatani, Kazuhiko

    2016-07-05

    The expansion of CAG repeats in the human genome causes the neurological disorder Huntington's disease. The small-molecule naphthyridine-azaquinolone NA we reported earlier bound to the CAG/CAG motif in the hairpin structure of the CAG repeat DNA. In order to investigate and improve NA-binding to the CAG repeat DNA and RNA, we conducted systematic structure-binding studies of NA to CAG repeats. Among the five new NA derivatives we synthesized, surface plasmon resonance (SPR) assay showed that all of the derivatives modified from amide linkages in NA to a carbamate linkage failed to bind to CAG repeat DNA and RNA. One derivative, NBzA, modified by incorporating an additional ring to the azaquinolone was found to bind to both d(CAG)9 and r(CAG)9 . NBzA binding to d(CAG)9 was similar to NA binding in terms of large changes in the SPR assay and circular dichroism (CD) as well as pairwise binding, as assessed by electron spray ionization time-of-flight (ESI-TOF) mass spectrometry. For the binding to r(CAG)9 , both NA and NBzA showed stepwise binding in ESI-TOF MS, and NBzA-binding to r(CAG)9 induced more extensive conformational change than NA-binding. The tricyclic system in NBzA did not show significant effects on the binding, selectivity, and translation, but provides a large chemical space for further modification to gain higher affinity and selectivity. These studies revealed that the linker structure in NA and NBzA was suitable for the binding to CAG DNA and RNA, and that the tricyclic benzoazaquinolone did not interfere with the binding. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Tricyclic antidepressants for attention deficit hyperactivity disorder (ADHD) in children and adolescents.

    Science.gov (United States)

    Otasowie, John; Castells, Xavier; Ehimare, Umonoibalo P; Smith, Clare H

    2014-09-19

    Attention deficit hyperactivity disorder (ADHD) is a chronic neurodevelopmental disorder of childhood onset, which may persist into adulthood. ADHD has a significant impact on a child's daily life, affecting relationships and academic performance. Its core symptoms include developmentally inappropriate levels of inattention, hyperactivity, and impulsive behaviour. Tricyclic antidepressants (TCAs) are sometimes used as second line of treatment in the reduction of ADHD symptoms in children and adolescents with ADHD. However, their efficacy is not yet known. To assess the efficacy of TCAs in the reduction of ADHD symptoms within the broad categories of hyperactivity, impulsivity, and inattentiveness in young people aged 6 to 18 years with established diagnoses of ADHD. On 26 September 2013, we searched CENTRAL, Ovid MEDLINE, Embase, PsycINFO, CINAHL, seven other databases, and two trials registers. We also searched the reference lists of relevant articles, and contacted manufacturers and known experts in the field to determine if there were any ongoing trials or unpublished studies available. Randomised controlled trials (RCTs), including both parallel group and cross-over study designs, of any dose of TCA compared with placebo or active medication in children or adolescents with ADHD, including those with comorbid conditions.  Working in pairs, three review authors independently screened records, extracted data, and assessed trial quality. We calculated the standardised mean differences (SMD) for continuous data, the odds ratio (OR) for dichotomous data, and 95% confidence intervals (CIs) for both. We conducted the meta-analyses using a random-effects model throughout. We used the Cochrane 'Risk of bias' tool to assess the risk of bias of each included trial and the GRADE approach to assess the quality of the body evidence. We included six RCTs with a total of 216 participants. Five of the six trials compared desipramine with placebo; the remaining trial compared

  14. Polycyclic Aromatic Hydrocarbons as Plausible Prebiotic Membrane Components

    Science.gov (United States)

    Groen, Joost; Deamer, David W.; Kros, Alexander; Ehrenfreund, Pascale

    2012-08-01

    Aromatic molecules delivered to the young Earth during the heavy bombardment phase in the early history of our solar system were likely to be among the most abundant and stable organic compounds available. The Aromatic World hypothesis suggests that aromatic molecules might function as container elements, energy transduction elements and templating genetic components for early life forms. To investigate the possible role of aromatic molecules as container elements, we incorporated different polycyclic aromatic hydrocarbons (PAH) in the membranes of fatty acid vesicles. The goal was to determine whether PAH could function as a stabilizing agent, similar to the role that cholesterol plays in membranes today. We studied vesicle size distribution, critical vesicle concentration and permeability of the bilayers using C6-C10 fatty acids mixed with amphiphilic PAH derivatives such as 1-hydroxypyrene, 9-anthracene carboxylic acid and 1,4 chrysene quinone. Dynamic Light Scattering (DLS) spectroscopy was used to measure the size distribution of vesicles and incorporation of PAH species was established by phase-contrast and epifluorescence microscopy. We employed conductimetric titration to determine the minimal concentration at which fatty acids could form stable vesicles in the presence of PAHs. We found that oxidized PAH derivatives can be incorporated into decanoic acid (DA) vesicle bilayers in mole ratios up to 1:10 (PAH:DA). Vesicle size distribution and critical vesicle concentration were largely unaffected by PAH incorporation, but 1-hydroxypyrene and 9-anthracene carboxylic acid lowered the permeability of fatty acid bilayers to small solutes up to 4-fold. These data represent the first indication of a cholesterol-like stabilizing effect of oxidized PAH derivatives in a simulated prebiotic membrane.

  15. Pharmacokinetics and pharmacodynamics of orally administered acetylenic tricyclic bis(cyanoenone), a highly potent Nrf2 activator with a reversible covalent mode of action

    Energy Technology Data Exchange (ETDEWEB)

    Kostov, Rumen V.; Knatko, Elena V.; McLaughlin, Lesley A.; Henderson, Colin J. [Jacqui Wood Cancer Centre, Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee, DD1 9SY, Scotland (United Kingdom); Zheng, Suqing [Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, NY, 11794 (United States); Huang, Jeffrey T.-J. [Jacqui Wood Cancer Centre, Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee, DD1 9SY, Scotland (United Kingdom); Honda, Tadashi [Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, NY, 11794 (United States); Dinkova-Kostova, Albena T., E-mail: a.dinkovakostova@dundee.ac.uk [Jacqui Wood Cancer Centre, Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee, DD1 9SY, Scotland (United Kingdom); Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205 (United States); Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21205 (United States)

    2015-09-25

    The acetylenic tricyclic bis(cyanoenone) TBE-31 is a highly potent cysteine targeting compound with a reversible covalent mode of action; its best-characterized target being Kelch-like ECH-associated protein-1 (Keap1), the cellular sensor for oxidants and electrophiles. TBE-31 reacts with cysteines of Keap1, impairing its ability to target nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) for degradation. Consequently, Nrf2 accumulates and orchestrates cytoprotective gene expression. In this study we investigated the pharmacokinetic and pharmacodynamic properties of TBE-31 in C57BL/6 mice. After a single oral dose of 10 μmol/kg (∼200 nmol/animal), the concentration of TBE-31 in blood exhibited two peaks, at 22.3 nM and at 15.5 nM, 40 min and 4 h after dosing, respectively, as determined by a quantitative stable isotope dilution LC-MS/MS method. The AUC{sub 0–24h} was 195.5 h/nmol/l, the terminal elimination half-life was 10.2 h, and the k{sub el} was 0.068 h{sup −1}. To assess the pharmacodynamics of Nrf2 activation by TBE-31, we determined the enzyme activity of its prototypic target, NAD(P)H:quinone oxidoreductase 1 (NQO1) and found it elevated by 2.4- and 1.5-fold in liver and heart, respectively. Continuous feeding for 18 days with diet delivering the same daily doses of TBE-31 under conditions of concurrent treatment with the immunosuppressive agent azathioprine had a similar effect on Nrf2 activation without any indications of toxicity. Together with previous reports showing the cytoprotective effects of TBE-31 in animal models of carcinogenesis, our results demonstrate the high potency, efficacy and suitability for chronic administration of cysteine targeting reversible covalent drugs. - Highlights: • TBE-31 is a cysteine targeting compound with a reversible covalent mode of action. • After a single oral dose, the blood concentration of TBE-31 exhibits two peaks. • Oral TBE-31 is a potent activator of Nrf2-dependent enzymes in

  16. d-AO spherical aromaticity in Ce6O8.

    Science.gov (United States)

    Yu, Xiaohu; Oganov, Artem R; Popov, Ivan A; Boldyrev, Alexander I

    2016-01-05

    After the first introduction of π aromaticity in chemistry to explain the bonding, structure, and reactivity of benzene and its derivatives, this concept was further applied to many other compounds featuring other types of aromaticity (i.e., σ, δ). Thus far, there have been no reports on d-AO-based spherical σ aromaticity. Here, we predict a highly stable bare Ce6O8 cluster of a spherical shape using evolutionary algorithm USPEX and DFT + U calculations. Natural bond orbital analysis, adaptive natural density partitioning algorithm, electron localization function, and partial charge plots demonstrate that bare Ce6O8 cluster exhibits d-AO spherical σ aromaticity, thus explaining its exotic geometry and stability. Ce6O8 complex plays an important role in many reactions and is known to exist in many forms, such as in NH4[Ce6(μ(3)O)5(μ(3)OH)3(μ(2)-C6H5COO)9(NO3)3(DMF)3]*DMF*H2O compound, which is prepared under room temperature, and acts as an oxidizing agent. © 2015 Wiley Periodicals, Inc.

  17. Amphipathic helices from aromatic amino acid oligomers.

    Science.gov (United States)

    Gillies, Elizabeth R; Dolain, Christel; Léger, Jean-Michel; Huc, Ivan

    2006-10-13

    Synthetic helical foldamers are of significant interest for mimicking the conformations of naturally occurring molecules while at the same time introducing new structures and properties. In particular, oligoamides of aromatic amino acids are attractive targets, as their folding is highly predictable and stable. Here the design and synthesis of new amphipathic helical oligoamides based on quinoline-derived amino acids having either hydrophobic or cationic side chains are described. Their structures were characterized in the solid state by single-crystal X-ray diffraction and in solution by NMR. Results of these studies suggest that an oligomer as short as a pentamer folds into a stable helical conformation in protic solvents, including MeOH and H(2)O. The introduction of polar proteinogenic side chains to these foldamers, as described here for the first time, promises to provide possibilities for the biological applications of these molecules. In particular, amphipathic helices are versatile targets to explore due to their importance in a variety of biological processes, and the unique structure and properties of the quinoline-derived oligoamides may allow new structure-activity relationships to be developed.

  18. source apportionment and distribution of polycyclic aromatic

    African Journals Online (AJOL)

    PTDFSA11_Laptop

    pyrogenic-derived from incomplete combustion of recent. (e.g., biomass .... aromatic hydrocarbons (PAHs) used as internal standards and surrogates: ..... w ood. Combustion petroleum petroleum petroleum. (a). SOURCE APPORTIONMENT AND DISTRIBUTION OF POLYCYCLIC AROMATIC HYDROCARBONS. 141 ...

  19. Formyl-d aromatic aldehydes

    International Nuclear Information System (INIS)

    Chancellor, T.; Quill, M.; Bergbreiter, D.E.; Newcomb, M.

    1978-01-01

    A simple exchange reaction for preparation of aldehydes labeled with deuterium at the formyl carbon is described. It can be successfully accomplished with several aromatic aldehydes, a catalytic or stoichiometric amount of either potassium cyanide or a thiazolium salt, a weak Lewis base, and deuterium oxide as the deuterium source

  20. Converting lignin to aromatics: step by step

    NARCIS (Netherlands)

    Strassberger, Z.I.

    2014-01-01

    Lignin, the glue that holds trees together, is the most abundant natural resource of aromatics. In that respect, it is a far more advanced resource than crude oil. This is because lignin already contains the aromatic functional groups. Thus, catalytic conversion of lignin to high-value aromatics is

  1. Stable Isotope Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples (skin, bone, blood, muscle) are analyzed for stable carbon, stable nitrogen, and stable sulfur analysis. Many samples are used in their entirety for...

  2. Synthesis of enantioenriched γ-quaternary cycloheptenones using a combined allylic alkylation/Stork–Danheiser approach: preparation of mono-, bi-, and tricyclic systems

    KAUST Repository

    Bennett, Nathan B.

    2012-01-01

    A general method for the synthesis of β-substituted and unsubstituted cycloheptenones bearing enantioenriched all-carbon γ-quaternary stereocenters is reported. Hydride or organometallic addition to a seven-membered ring vinylogous ester followed by finely tuned quenching parameters achieves elimination to the corresponding cycloheptenone. The resulting enones are elaborated to bi- and tricyclic compounds with potential for the preparation of non-natural analogs and whose structures are embedded in a number of cycloheptanoid natural products.

  3. Inhibition of /sup 22/Na influx by tricyclic and tetracyclic antidepressants and binding of (/sup 3/H)imipramine in bovine adrenal medullary cells

    Energy Technology Data Exchange (ETDEWEB)

    Arita, M.; Wada, A.; Takara, H.; Izumi, F.

    1987-10-01

    In bovine adrenal medullary cells we investigated the effects of antidepressants on ionic channels and secretion of catecholamines. Tricyclic (imipramine, amitriptyline and nortriptyline) and tetracyclic (maprotiline and mianserin) antidepressants inhibited carbachol-induced influx of /sup 22/Na, /sup 45/Ca and secretion of catecholamines (IC50, 14-96 microM). Influx of /sup 22/Na, /sup 45/Ca and secretion of catecholamines due to veratridine also were inhibited by these drugs (IC50, 10-17 microM). However, antidepressants did not suppress high concentration of K-induced 45Ca influx and catecholamine secretion, suggesting that antidepressants do not inhibit voltage-dependent Ca channels. (/sup 3/H)Imipramine bound specifically to adrenal medullary cells. Binding was saturable, reversible and with two different equilibrium dissociation constants (13.3 and 165.0 microM). Tricyclic and tetracyclic antidepressants competed for the specific binding of (/sup 3/H)imipramine at the same concentrations as they inhibited /sup 22/Na influx caused by carbachol or veratridine. Carbachol, d-tubocurarine, hexamethonium, tetrodotoxin, veratridine and scorpion venom did not inhibit the specific binding of (/sup 3/H)imipramine. These results suggest that tricyclic and tetracyclic antidepressants bind to two populations of binding sites which are functionally associated with nicotinic receptor-associated ionic channels and with voltage-dependent Na channels, and inhibit Na influx. Inhibition of Na influx leads to the reduction of Ca influx and catecholamine secretion caused by carbachol or veratridine.

  4. Inhibition of 22Na influx by tricyclic and tetracyclic antidepressants and binding of [3H]imipramine in bovine adrenal medullary cells

    International Nuclear Information System (INIS)

    Arita, M.; Wada, A.; Takara, H.; Izumi, F.

    1987-01-01

    In bovine adrenal medullary cells we investigated the effects of antidepressants on ionic channels and secretion of catecholamines. Tricyclic (imipramine, amitriptyline and nortriptyline) and tetracyclic (maprotiline and mianserin) antidepressants inhibited carbachol-induced influx of 22 Na, 45 Ca and secretion of catecholamines (IC50, 14-96 microM). Influx of 22 Na, 45 Ca and secretion of catecholamines due to veratridine also were inhibited by these drugs (IC50, 10-17 microM). However, antidepressants did not suppress high concentration of K-induced 45Ca influx and catecholamine secretion, suggesting that antidepressants do not inhibit voltage-dependent Ca channels. [ 3 H]Imipramine bound specifically to adrenal medullary cells. Binding was saturable, reversible and with two different equilibrium dissociation constants (13.3 and 165.0 microM). Tricyclic and tetracyclic antidepressants competed for the specific binding of [ 3 H]imipramine at the same concentrations as they inhibited 22 Na influx caused by carbachol or veratridine. Carbachol, d-tubocurarine, hexamethonium, tetrodotoxin, veratridine and scorpion venom did not inhibit the specific binding of [ 3 H]imipramine. These results suggest that tricyclic and tetracyclic antidepressants bind to two populations of binding sites which are functionally associated with nicotinic receptor-associated ionic channels and with voltage-dependent Na channels, and inhibit Na influx. Inhibition of Na influx leads to the reduction of Ca influx and catecholamine secretion caused by carbachol or veratridine

  5. Effect of tricyclic antidepressants on transmitter-stimulated inositol phosphate production in rat brain cortex in vitro

    International Nuclear Information System (INIS)

    Nomura, S.; Enna, S.J.

    1986-01-01

    Tricyclic antidepressants (TCAs) have anticholinergic and α-adrenergic blocking properties. The present study was undertaken to examine the effects of amitriptyline, imipramine, and desipramine on inositol phosphate accumulation, a brain second messenger system associated with cholinergic and adrenergic receptors. Whereas the TCAs were 28 to 400-fold weaker than atropine as inhibitors of 3 H-QNB binding to brain cholinergic receptors, they were 600 to 2000-fold less active than atropine as inhibitors of carbachol-stimulated IP accumulation in brain. In contrast, the relative potencies of the TCAs and prazosin to inhibit norepinephrine-stimulated IP accumulation and 3 H-prazosin binding appeared to be similar in the two assays. The results suggest pharmacological differences between the cholinergic receptors labeled in the ONB binding assay and those mediating the IP response, whereas the α 1 -adrenergic receptors appear to be similar in the two systems. Since atropine is considered a nonselective muscarinic antagonist, it is possible that the TCAs may differentiate between cholinergic receptor subtypes, which may be an important component of their clinical response

  6. Common multiple interactions of tricyclic anti-depressants and orphenadrine with liver microsomal cytochrome P450 enzymes of the rat.

    Science.gov (United States)

    Roos, P H

    1999-06-01

    1. Interactions of tricylic anti-depressants (TCA) and structurally related drugs with rat microsomal cytochromes P450 were studied including competitive inhibition of enzymatic activities and formation of P450 metabolite complexes. 2. All compounds examined that carry a methylated aminoalkyl sidechain formed metabolite complexes with microsomal P450 of the untreated male rat. The extent of complex formation is only slightly altered by rat pre-treatment with P450 inducers indicating that mainly constitutive P450 enzymes are involved. 3. The kinetics of in vitro complex formation differed for the di- and monomethylamino derivatives of the TCA showing either a sigmoidal or hyperbolic shape respectively. Considerable auto-inhibition of complex formation is observed at concentrations > 100 microM only with the dimethyl derivatives. 4. Besides metabolite complex formation, a further effect of the drugs is competitive inhibition of the CYP2B-dependent pentoxyresorufin O-dealkylation. The inhibitory potential of the drugs depends on their degree of N-alkyl substitution. Correspondingly, the Ki is in the range of 2.8-7.1, 0.1-0.2 and 0.01 microM for the dimethyl-, monomethyl- and unsubstituted drugs respectively. 5. It has been shown that P450 interactions with tricyclic anti-depressants include several types of mechanisms and several P450 enzymes. It might be pharmacologically important that the dimethylamino compounds are demethylated in vivo by cytochromes P450 giving rise to more potent P450 inhibitors compared with the parent compounds.

  7. Clinical characteristics, pharmacotherapy, and healthcare resource use among patients with fibromyalgia newly prescribed pregabalin or tricyclic antidepressants.

    Science.gov (United States)

    Gore, Mugdha; Tai, Kei-Sing; Chandran, Arthi; Zlateva, Gergana; Leslie, Douglas

    2012-01-01

    To examine treatment patterns and costs among patients with fibromyalgia prescribed pregabalin or tricyclic antidepressants (TCAs). Using the LifeLink™ Health Plan Claims Database, patients with fibromyalgia (International Classification of Diseases, Ninth Revision, Clinical Modification code 729.1X) newly prescribed (index date) TCAs (n = 898) were identified and propensity score-matched (PSM) with patients newly prescribed pregabalin (n = 898). Pain-related pharmacotherapy, comorbidities, and healthcare resource use/costs were examined during the 12 months, pre-index, and follow-up periods. Both patient groups reported multiple comorbidities and received pain medications in the pre-index and follow-up periods. Among patients prescribed pregabalin, use of non-selective non-steroidal anti-inflammatory drugs (43.3% vs 39.8%), other anticonvulsants (28.6% vs 23.3%), and tetracyclic/miscellaneous antidepressants (28.5% vs 25.8%) significantly decreased, and cyclooxygenase 2 (COX-2) inhibitors (7.7% vs 10.4%), TCAs (4.8% vs 7.9%), and topical agents (10.8% vs 15.1%) increased in the follow-up period (p fibromyalgia to pregabalin. Patients with fibromyalgia prescribed pregabalin or TCAs had multiple comorbidities and a sizeable pain medication burden, which increased in the follow-up period for both cohorts. Only 5% of pregabalin initiators had been treated with concomitant TCAs at baseline, suggesting that TCAs were inappropriate for these patients owing to their contraindications.

  8. Functionalized tricyclic cytosine analogues provide nucleoside fluorophores with improved photophysical properties and a range of solvent sensitivities.

    Science.gov (United States)

    Rodgers, Brittney J; Elsharif, Nada A; Vashisht, Nisha; Mingus, Macy M; Mulvahill, Mark A; Stengel, Gudrun; Kuchta, Robert D; Purse, Byron W

    2014-02-10

    Tricyclic cytosines (tC and tC(O) frameworks) have emerged as a unique class of fluorescent nucleobase analogues that minimally perturb the structure of B-form DNA and that are not quenched in duplex nucleic acids. Systematic derivatization of these frameworks is a likely approach to improve on and diversify photophysical properties, but has not so far been examined. Synthetic methods were refined to improve on tolerance for electron-donating and electron-withdrawing groups, resulting in a series of eight new, fluorescent cytidine analogues. Photophysical studies show that substitution of the framework results in a pattern of effects largely consistent across tC and tC(O) and provides nucleoside fluorophores that are brighter than either parent. Moreover, a range of solvent sensitivities is observed, offering promise that this family of probes can be extended to new applications that require reporting on the local environment. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Two-electron Oxidation of a Twisted Non Anti-aromatic 40π ...

    Indian Academy of Sciences (India)

    Abstract. Expanded isophlorins are typical examples for stable anti-aromatic systems. Paratropic ring cur- rent effects are observed in their NMR spectra mainly due to their planar conformation. Herein we report the synthesis of the first twisted 40π expanded isophlorin and also its two-electron oxidation to a 38π dication.

  10. Alkylation of organic aromatic compounds

    Science.gov (United States)

    Smith, L.A. Jr.

    1989-07-18

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  11. Alkylation of organic aromatic compounds

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1989-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  12. The direct aromatization of methane

    Energy Technology Data Exchange (ETDEWEB)

    Marcelin, G.; Oukaci, R.; Migone, R.A.; Kazi, A.M. [Altamira Instruments, Pittsburgh, PA (United States)

    1995-12-31

    The thermal decomposition of methane shows significant potential as a process for the production of higher unsaturated and aromatic hydrocarbons when the extent of the reaction is limited. Thermodynamic calculations have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that cooling the product and reacting gases as the reaction proceeds can significantly reduce or eliminate the formation of solid carbon and heavier (C{sub 10+}) materials. Much work remains to be done in optimizing the quenching process and this is one of the goals of this program. Means to lower the temperature of the reaction are being studied as this result in a more feasible commercial process due to savings realized in energy and material of construction costs. The use of free-radical generators and catalysts will be investigated as a means of lowering the reaction temperature thus allowing faster quenching. It is highly likely that such studies will lead to a successful direct methane to higher hydrocarbon process.

  13. Dehalogenation of halogenated aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Griller, D.; Hawari, J.A.; McPhee, D.J.

    1992-03-03

    A process is disclosed for dehalogenating aromatic halogenated compounds, comprising reacting an alkali metal with the halogenated aromatic material in the presence of a liquid hydrosiloxane until substantially all of the halogen has reacted, leaving the aromatic moiety in non-halogenated form. Preferably a non-halogenated non-aqueous polar solvent or diluent is present during the reaction. The excess alkali metal can be reacted with added termination agent, and excess hydrosiloxane can be precipitated and the solids separated. According to a further aspect of the invention, a kit is provided for carrying out the above dehalogenation process. The kit comprises a container containing alkali metal, a container containing liquid hydrosiloxane, or one container containing both the alkali metal and the hydrosiloxane. The starting material to be dehalogenated, in most applications of the process, will be polychlorinated biphenyls alone or as mixtures with various oils such as transformer oils. The alkali metal may be Li, Na, or K, and the hydrosiloxane should be a liquid miscible with the starting material, preferably a polyorganohydrosiloxane of relatively low molecular weight. Experiments are described to illustrate the process of the invention. It is shown that the process of the invention provides significantly improved dehalogenations at ambient temperatures and may be used for destruction of polychlorinated biphenyls to the point where they can no longer be detected by gas chromatography.

  14. Stable convergence and stable limit theorems

    CERN Document Server

    Häusler, Erich

    2015-01-01

    The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

  15. Spectroscopic Diagnosis of Excited-State Aromaticity: Capturing Electronic Structures and Conformations upon Aromaticity Reversal.

    Science.gov (United States)

    Oh, Juwon; Sung, Young Mo; Hong, Yongseok; Kim, Dongho

    2018-03-06

    Aromaticity, the special energetic stability derived from cyclic [4 n + 2]π-conjugated electronic structures, has been the topic of intense interest in chemistry because it plays a critical role in rationalizing molecular stability, reactivity, and physical/chemical properties. Recently, the pioneering work by Colin Baird on aromaticity reversal, postulating that aromatic (antiaromatic) character in the ground state reverses to antiaromatic (aromatic) character in the lowest excited triplet state, has attracted much scientific attention. The completely reversed aromaticity in the excited state provides direct insight into understanding the photophysical/chemical properties of photoactive materials. In turn, the application of aromatic molecules to photoactive materials has led to numerous studies revealing this aromaticity reversal. However, most studies of excited-state aromaticity have been based on the theoretical point of view. The experimental evaluation of aromaticity in the excited state is still challenging and strenuous because the assessment of (anti)aromaticity with conventional magnetic, energetic, and geometric indices is difficult in the excited state, which practically restricts the extension and application of the concept of excited-state aromaticity. Time-resolved optical spectroscopies can provide a new and alternative avenue to evaluate excited-state aromaticity experimentally while observing changes in the molecular features in the excited states. Time-resolved optical spectroscopies take advantage of ultrafast laser pulses to achieve high time resolution, making them suitable for monitoring ultrafast changes in the excited states of molecular systems. This can provide valuable information for understanding the aromaticity reversal. This Account presents recent breakthroughs in the experimental assessment of excited-state aromaticity and the verification of aromaticity reversal with time-resolved optical spectroscopic measurements. To

  16. Noncomparative scaling of aromaticity through electron itinerancy

    International Nuclear Information System (INIS)

    Paul, Satadal; Goswami, Tamal; Misra, Anirban

    2015-01-01

    Aromaticity is a multidimensional concept and not a directly observable. These facts have always stood in the way of developing an appropriate theoretical framework for scaling of aromaticity. In the present work, a quantitative account of aromaticity is developed on the basis of cyclic delocalization of π-electrons, which is the phenomenon leading to unique features of aromatic molecules. The stabilization in molecular energy, caused by delocalization of π-electrons is obtained as a second order perturbation energy for archetypal aromatic systems. The final expression parameterizes the aromatic stabilization energy in terms of atom to atom charge transfer integral, onsite repulsion energy and the population of spin orbitals at each site in the delocalized π-electrons. An appropriate computational platform is framed to compute each and individual parameter in the derived equation. The numerical values of aromatic stabilization energies obtained for various aromatic molecules are found to be in close agreement with available theoretical and experimental reports. Thus the reliable estimate of aromaticity through the proposed formalism renders it as a useful tool for the direct assessment of aromaticity, which has been a long standing problem in chemistry

  17. Selective serotonin reuptake inhibitors versus tricyclic antidepressants in young patients: a meta-analysis of efficacy and acceptability.

    Science.gov (United States)

    Qin, Bin; Zhang, Yuqing; Zhou, Xinyu; Cheng, Pengfei; Liu, Yiyun; Chen, Jin; Fu, Yuying; Luo, Qinghua; Xie, Peng

    2014-07-01

    A meta-analysis comparing the efficacy and acceptability of selective serotonin reuptake inhibitors (SSRIs) versus tricyclic antidepressants (TCAs) in depressed children, adolescents, and young adults was performed. A comprehensive literature search of the PubMed, Cochrane, Embase, Web of Science, and PsycINFO databases was conducted from 1970 to December 2013. Only clinical trials that randomly assigned one SSRI or TCA to patients aged 7 to 25 years who met the diagnostic criteria for unipolar depressive disorder were included. Primary efficacy was determined by the pooling of standardized mean differences (SMDs) calculated from the difference in the reduction in mean depression rating scale scores for the 2 antidepressants. Acceptability was determined by pooling the risk ratios (RRs) of dropouts for all reasons and for adverse effects as well as the suicide-risk outcome. Five trials with a total of 422 patients were considered to be eligible for inclusion. SSRIs were significantly more effective than TCAs in primary efficacy (SMD = -0.52; 95% CI, -0.81 to -0.24; P = 0.0003). Patients taking SSRIs had a significantly greater response to depressive symptoms than patients taking TCAs (RR = 1.55; 95% CI, 1.04 to 2.29; P = 0.03). On an individual SSRI basis, fluoxetine had a significantly greater efficacy than TCAs (SMD = -0.82; 95% CI, -1.34 to -0.29; P = 0.003). On an individual TCA basis, only imipramine was not significantly worse than SSRIs (SMD = -0.27; 95% CI, -0.56 to 0.02; P = 0.06). Significantly more patients taking TCAs discontinued treatment than patients taking SSRIs (35.8% vs 25.1%; RR = 0.70; 95% CI, 0.52 to 0.93; P = 0.02). SSRI therapy has a superior efficacy and is better tolerated compared with TCA therapy in young patients. Copyright © 2014 Elsevier HS Journals, Inc. All rights reserved.

  18. Randomized trial of opioids versus tricyclic antidepressants for radiation-induced mucositis pain in head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ehrnrooth, E.; Grau, C.; Zachariae, R.; Andersen, Joern [Aarhus Univ. Hospital (Denmark). Dept. of Oncology

    2001-11-01

    Patients who receive radiotherapy for head and neck cancer are likely to develop painful mucositis. The pain is characterized by a burning or stinging sensation similar to neuropathic pain sensations. The purpose of the present study was to compare the analgesic effect of a tricyclic antidepressant (TC), commonly used in the treatment of neuropathic pain, with the effect of opioids on radiation-induced mucositis pain. Forty-three patients receiving 66-68 Gy external radiation according to the DAHANCA guidelines (the Danish Head and Neck Cancer Study Group) were randomized to either morphine or TC when mucositis pain was insufficiently managed with weak analgesics. Patients with insufficient pain control in either treatment arm received supplementary medication from the opposite treatment arm. Pain was evaluated weekly using a VAS scale and the McGill Pain Questionnaire. The degree of mucositis and the degree of depression were measured at the same time intervals. Twenty-two patients entered the opioid arm and 21 the TC arm. Two patients in each arm were non-evaluable. VAS pain scores were significantly reduced in the opioid treatment arm one week after randomization (p=0.01). Eight patients in the TC arm were managed with TC alone, but for 11 patients it was necessary to add morphine. The 20 evaluable patients in the morphine arm required no additional treatment. There were no significant differences in side effects between the two groups. Higher pain scores in the TC arm, but not in the opioid arm, were significantly correlated with higher BDI scores. Some head and neck cancer patients with radiation-induced nucositis pain may have sufficient pain control on TC alone. This might be useful in patients with relative counter-indications to opioid treatment.

  19. Tricyclic antidepressant amitriptyline indirectly increases the proliferation of adult dentate gyrus-derived neural precursors: an involvement of astrocytes.

    Directory of Open Access Journals (Sweden)

    Shuken Boku

    Full Text Available Antidepressants increase the proliferation of neural precursors in adult dentate gyrus (DG, which is considered to be involved in the therapeutic action of antidepressants. However, the mechanism underlying it remains unclear. By using cultured adult rat DG-derived neural precursors (ADP, we have already shown that antidepressants have no direct effects on ADP. Therefore, antidepressants may increase the proliferation of neural precursors in adult DG via unknown indirect mechanism. We have also shown that amitriptyline (AMI, a tricyclic antidepressant, induces the expressions of GDNF, BDNF, FGF2 and VEGF, common neurogenic factors, in primary cultured astrocytes (PCA. These suggest that AMI-induced factors in astrocytes may increase the proliferation of neural precursors in adult DG. To test this hypothesis, we examined the effects of AMI-induced factors and conditioned medium (CM from PCA treated with AMI on ADP proliferation. The effects of CM and factors on ADP proliferation were examined with BrdU immunocytochemistry. AMI had no effect on ADP proliferation, but AMI-treated CM increased it. The receptors of GDNF, BDNF and FGF2, but not VEGF, were expressed in ADP. FGF2 significantly increased ADP proliferation, but not BDNF and GDNF. In addition, both of a specific inhibitor of FGF receptors and anti-FGF2 antibody significantly counteracted the increasing effect of CM on ADP proliferation. In addition, FGF2 in brain is mainly derived from astrocytes that are key components of the neurogenic niches in adult DG. These suggest that AMI may increase ADP proliferation indirectly via PCA and that FGF2 may a potential candidate to mediate such an indirect effect of AMI on ADP proliferation via astrocytes.

  20. Randomized trial of opioids versus tricyclic antidepressants for radiation-induced mucositis pain in head and neck cancer

    International Nuclear Information System (INIS)

    Ehrnrooth, E.; Grau, C.; Zachariae, R.; Andersen, Joern

    2001-01-01

    Patients who receive radiotherapy for head and neck cancer are likely to develop painful mucositis. The pain is characterized by a burning or stinging sensation similar to neuropathic pain sensations. The purpose of the present study was to compare the analgesic effect of a tricyclic antidepressant (TC), commonly used in the treatment of neuropathic pain, with the effect of opioids on radiation-induced mucositis pain. Forty-three patients receiving 66-68 Gy external radiation according to the DAHANCA guidelines (the Danish Head and Neck Cancer Study Group) were randomized to either morphine or TC when mucositis pain was insufficiently managed with weak analgesics. Patients with insufficient pain control in either treatment arm received supplementary medication from the opposite treatment arm. Pain was evaluated weekly using a VAS scale and the McGill Pain Questionnaire. The degree of mucositis and the degree of depression were measured at the same time intervals. Twenty-two patients entered the opioid arm and 21 the TC arm. Two patients in each arm were non-evaluable. VAS pain scores were significantly reduced in the opioid treatment arm one week after randomization (p=0.01). Eight patients in the TC arm were managed with TC alone, but for 11 patients it was necessary to add morphine. The 20 evaluable patients in the morphine arm required no additional treatment. There were no significant differences in side effects between the two groups. Higher pain scores in the TC arm, but not in the opioid arm, were significantly correlated with higher BDI scores. Some head and neck cancer patients with radiation-induced nucositis pain may have sufficient pain control on TC alone. This might be useful in patients with relative counter-indications to opioid treatment

  1. Persistence of polycyclic aromatic hydrocarbon components of creosote under anaerobic enrichment conditions.

    Science.gov (United States)

    Sharak Genthner, B R; Townsend, G T; Lantz, S E; Mueller, J G

    1997-01-01

    Anaerobic biodegradation of an artificial mixture of polycyclic aromatic hydrocarbons (PAHs), which simulates the PAH component of creosote, was examined under methanogenic, sulfidogenic, and nitrate-reducing conditions using creosote-contaminated sediment as the source of inoculum. PAH degradation, CH4 formation and ion reduction were monitored for up to one year. Despite demonstrating active methanogenic and nitrate-reducing anaerobic bacterial communities, only limited degradation of a few PAHs was observed. Under methanogenic conditions limited degradation of all bicyclic (naphthalene, 1-and 2-methylnaphthalene, biphenyl, and 2,6-dimethylnaphthalene) and one tricyclic PAH, anthraquinone, was detected. 2-Methylanthracene was apparently degraded under nitrate-reducing conditions. Anthraquinone declined in sulfate enrichments, but this decline was not dependent upon sulfate reduction. None of the 4- or 5-ring PAHs were degraded under any of the enrichment conditions. These data indicate that under the anaerobic conditions tested there is only a limited potential to degrade PAHs which must be considered when proposing bioremediation technologies for PAH-contaminated sites, especially if high-molecular-weight PAHs are present.

  2. Gone or Just out of Sight? the Apparent Disappearance of Aromatic Litter Components in Soils

    Science.gov (United States)

    Klotzbücher, T.; Kalbitz, K.; Cerli, C.; Hernes, P.; Kaiser, K.

    2014-12-01

    We present a literature study on controversies concerning the degradation of lignin and other aromatic litter components in soils. Lignin concentrations control rates of litter decomposition within biomes worldwide, implying that lignin is among the most resistant litter components. Consequently, lignin has been traditionally linked to the concept of soil organic matter (SOM) stability due to recalcitrance. However, studies using molecular-level analytics (e.g., CuO oxidation) suggest significant chemical alterations and losses of lignin components during litter decomposition. Lignin degradation occurs step-wise, including (i) depolymerization and (ii) further transformation of water-soluble depolymerization products. The long-term fate of depolymerization products and of other soluble aromatic litter components in mineral soils is still a mystery. Research on dissolved organic matter (DOM) indicates that they are important precursors of stable SOM attached to mineral surfaces. In laboratory experiments, aromatics were among the most resistant DOM components and prone to bind strongly to minerals. In accord, field data from various sites showed decreases of aromatic DOM during passage of mineral soil, presumably due to organic-mineral interaction. Recent research on composition of solid-phase SOM, however, contradicts DOM research. It finds that mineral-associated SOM is rather dominated by non-aromatic, microbial-derived compounds. Other studies suggest the turnover of lignin in soil to be faster than the turnover of bulk SOM. We assume that the contradictions might be due to difficulties in the analysis of aromatics. We conclude that we currently lack of understanding on long-term fate of major litter constituents and on contribution of aromatics to stable SOM. Careful data re-interpretation of available data, critical assessment of analytical limitations, and combined studies on DOM and solid-phase SOM might be ways to overcome contrasting perspectives.

  3. Aromaticity of distorted benzene rings: exploring the validity of different indicators of aromaticity.

    Science.gov (United States)

    Feixas, Ferran; Matito, Eduard; Poater, Jordi; Solà, Miquel

    2007-05-24

    The effect of three in-plane (bond length alternation, bond length elongation, and clamping) and three out-of-plane deformations (boatlike, chairlike, and pyramidalization) on the aromaticity of the benzene molecule has been analyzed employing seven widely used indicators of aromaticity. It is shown that only the aromatic fluctuation index (FLU) is able to indicate the expected loss of aromaticity because of distortion from the equilibrium geometry in all deformations analyzed. As FLU has been shown previously to fail in other particular situations, we conclude that there is not yet a single indicator of aromaticity that works properly for all cases. Therefore, to reach safer conclusions, aromaticity analyses should be carried out employing a set of aromaticity descriptors on the basis of different physical manifestations of aromaticity.

  4. AROMATIC AND POLYCYCLIC AROMATIC HYDROCARBON FORMATION IN A LAMINAR PREMIXED N-BUTANE FLAME. (R825412)

    Science.gov (United States)

    AbstractExperimental and detailed chemical kinetic modeling work has been performed to investigate aromatic and polycyclic aromatic hydrocarbon (PAH) formation pathways in a premixed, rich, sooting, n-butane¯oxygen¯argon burner s...

  5. stableGP

    Data.gov (United States)

    National Aeronautics and Space Administration — The code in the stableGP package implements Gaussian process calculations using efficient and numerically stable algorithms. Description of the algorithms is in the...

  6. Substrate specific hydrolysis of aromatic and aromatic-aliphatic esters in orchid tissue cultures

    Directory of Open Access Journals (Sweden)

    Agnieszka Mironowicz

    2014-01-01

    Full Text Available We found that tissue cultures of higher plants were able, similarly as microorganisms, to transform low-molecular-weight chemical compounds. In tissue cultures of orchids (Cymbidium 'Saint Pierre' and Dendrobium phalaenopsis acetates of phenols and aromatic-aliphatic alcohols were hydrolyzed, whereas methyl esters of aromatic and aromatic-aliphatic acids did not undergo this reaction. Acetates of racemic aromatic-aliphatic alcohols were hydrolyzed with distinct enantiospecificity.

  7. Quantum transport through aromatic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, J. H., E-mail: judith.ojeda@uptc.edu.co [Instituto de Alta investigación, Universidad de Tarapaca, Casilla 7D Arica (Chile); Grupo de Física de Materiales, Escuela de Física, Universidad Pedagógica y Tecnológica de Colombia, Tunja (Colombia); Rey-González, R. R. [Departamento de Física, Universidad Nacional de Colombia, Bogotá D. C. (Colombia); Laroze, D. [Instituto de Alta investigación, Universidad de Tarapaca, Casilla 7D Arica (Chile)

    2013-12-07

    In this paper, we study the electronic transport properties through aromatic molecules connected to two semi-infinite leads. The molecules are in different geometrical configurations including arrays. Using a nearest neighbor tight-binding approach, the transport properties are analyzed into a Green's function technique within a real-space renormalization scheme. We calculate the transmission probability and the Current-Voltage characteristics as a function of a molecule-leads coupling parameter. Our results show different transport regimes for these systems, exhibiting metal-semiconductor-insulator transitions and the possibility to employ them in molecular devices.

  8. Selective Production of Aromatics from 2-Octanol on Zinc Ion-Exchanged MFI Zeolite Catalysts

    OpenAIRE

    Iwamoto, Masakazu; Takezawa, Ryota; Morimoto, Masao

    2015-01-01

    The aromatization of 2-octanol derived from castor oil as a byproduct in the formation of sebacic acid was investigated on various zeolite catalysts. Zn ion-exchanged MFI (ZSM-5) zeolites with small silica/alumina ratios and zinc contents of 0.5 to 2.0 wt. % were determined to exhibit good and stable activity for the reaction at 623 to 823 K. The yield of aromatics was 62% at 773 K and the space velocity 350 to 1400 h−1. The temperature and contact time dependences of the product distribution...

  9. Stereoselective Construction of Spiro-Fused Tricyclic Frameworks by Sequential Reaction of Enynes, Imines, and Diazoalkenes with Rh(I) and Rh(II) Catalysts.

    Science.gov (United States)

    Hato, Yoshio; Oonishi, Yoshihiro; Yamamoto, Yasunori; Nakajima, Kiyohiko; Sato, Yoshihiro

    2016-09-02

    Stereoselective construction of spiro-fused tricyclic compounds from enynes having a tethered imine with diazoalkenes was achieved by Rh(I)- and Rh(II)-catalyzed sequential reactions. This method consists of three reactions, i.e., Rh(I)-catalyzed cyclization of enynes with a tethered imine, Rh(II)-catalyzed cyclopropanation with diazoalkenes, and Cope rearrangement. Notably, the sequential reactions can be operated in one pot, in which Rh(I) and Rh(II) catalysts work in relay without any serious catalyst deactivation to afford the spirocycles in a stereoselective manner.

  10. Birds and polycyclic aromatic hydrocarbons

    Science.gov (United States)

    Albers, P.H.

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAH) are present throughout the global environment and are produced naturally and by activities of humans. Effects of PAH on birds have been determined by studies employing egg injection, egg immersion, egg shell application, single and multiple oral doses, subcutaneous injection, and chemical analysis of field-collected eggs and tissue. The four-to six-ring aromatic compounds are the most toxic to embryos, young birds, and adult birds. For embryos, effects include death, developmental abnormalities, and a variety of cellular and biochemical responses. For adult and young birds, effects include reduced egg production and hatching, increased clutch or brood abandonment, reduced growth, increased organweights, and a variety of biochemical responses. Trophic level accumulation is unlikely. Environmental exposure to PAH in areas of high human population or habitats affected by recent petroleum spills might be sufficient to adversely affect reproduction. Evidence of long-term effects of elevated concentrations of environmental PAH on bird populations is very limited and the mechanisms of effect are unclear.

  11. Theoretical studies of the structures and local aromaticity of conjugated polycyclic hydrocarbons using three aromatic indices

    Science.gov (United States)

    Sakai, Shogo; Kita, Yuki

    2013-07-01

    The structures and local aromaticity of some conjugated polycyclic hydrocarbons (from the butadienoid, acene, and phenylene series) are studied using ab initio MO and density functional methods. The aromaticities of the molecules are estimated using three indices: the nucleus-independent chemical shift (NICS), the harmonic oscillator model of aromaticity (HOMA), and the index of deviation from aromaticity (IDA). Assessment of the relationships between the structures and the aromatic indices shows that the IDA values correspond best to the characteristics of the conjugated polycyclic hydrocarbon structures.

  12. Composition and source diagnostics of polycyclic aromatic ...

    African Journals Online (AJOL)

    Composition and source diagnostics of polycyclic aromatic hydrocarbons in sediments from Elelenwo Creek, southern Nigeria. I Agbozu, K Opuene, O Benson. Abstract. The survey of polycyclic aromatic hydrocarbons (PAHs) and their relation to potential pollution sources was carried out in sediments from Elelenwo Creek, ...

  13. Aromatic saturation of distillates. An overview

    International Nuclear Information System (INIS)

    Cooper, Barry H.; Donnis, Bjoern B.L.

    1996-01-01

    The saturation of aromatic compounds in distillate fractions and in particular in diesel fuel has received considerable attention in recent years. A high aromatic content is associated with poor fuel quality, giving a low cetane number in diesel fuel and a high smoke point in jet fuel. There is also evidence that particulate emissions in diesel exhaust gases correlate with the aromatic content of the fuel. New legislation has been introduced to limit aromatics in diesel fuel and this has led to new catalyst and process developments for aromatic saturation. This paper gives an overview of these developments. The types of aromatic compounds found in distillate streams are described, and the kinetics of both single (model) compounds and groups of compounds as found in industrial feedstocks are discussed. Both supported metal sulfide and supported noble metal catalysts are used industrially and the paper outlines the role of the active species in these catalysts and compares reaction conditions used for each. The tolerance of different catalyst systems towards sulfur and nitrogen in the feed is dealt with in some detail. Commercial processes employ either single- or dual-stage catalyst systems depending on the nature of the aromatic saturation catalyst. The paper considers the merits of different process configurations. The paper concludes with a brief survey of possible future applications for distillate aromatic saturation catalysts

  14. Quantifying aromaticity with electron delocalisation measures.

    Science.gov (United States)

    Feixas, Ferran; Matito, Eduard; Poater, Jordi; Solà, Miquel

    2015-09-21

    Aromaticity cannot be measured directly by any physical or chemical experiment because it is not a well-defined magnitude. Its quantification is done indirectly from the measure of different properties that are usually found in aromatic compounds such as bond length equalisation, energetic stabilisation, and particular magnetic behaviour associated with induced ring currents. These properties have been used to set up the myriad of structural-, energetic-, and magnetic-based indices of aromaticity known to date. The cyclic delocalisation of mobile electrons in two or three dimensions is probably one of the key aspects that characterise aromatic compounds. However, it has not been until the last decade that electron delocalisation measures have been widely employed to quantify aromaticity. Some of these new indicators of aromaticity such as the PDI, FLU, ING, and INB were defined in our group. In this paper, we review the different existing descriptors of aromaticity that are based on electron delocalisation properties, we compare their performance with indices based on other properties, and we summarise a number of applications of electronic-based indices for the analysis of aromaticity in interesting chemical problems.

  15. Synthesis and biological evaluation of 12N-substituted tricyclic matrinic derivatives as a novel family of anti-influenza agents.

    Science.gov (United States)

    Tang, Sheng; Li, Yu-Huan; Cheng, Xin-Yue; Yin, Jin-Qiu; Li, Ying-Hong; Song, Dan-Qing; Wang, Yan-Xiang; Liu, Zhan-Dong

    2018-02-21

    Influenza is still a serious threat to human health with significant morbidity and mortality, so it is desirable to develop novel anti-flu drug agents with novel structures. The main purpose of this research was to explore broad-spectrum anti-flu agents and provide antiviral stockpiles in response to potential future influenza pandemics. Fifteen novel 12N-substituted tricyclic matrinic derivatives were synthesized and evaluated for their anti-influenza activities against H1N1 subtype taking 12N-p-cyanobenzenesulfonyl matrinane (1) as the lead. All prepared compounds were characterized by 1H NMR, 13C NMR and ESI-HRMS. The pharmacokinetics (PK) profile of the key compound was also examined in this study. The structure-activity relationship study indicated that a suitable benzyl groups on 12N atom might be beneficial for the activity. Among them, 12N-p-carboxybenzyl matrinic butane (17g) exhibited the most promising activity with an IC50 value of 16.2 μM and a selective index (SI) value of over 33.4. In addition, compound 17g displayed a good in vivo pharmacokinetic profile with area under the curve (AUC0-∞) value of 9.89 μM•h. We consider tricyclic matrinic butane derivatives to be a new class of anti-influenza agents and this study provided useful information on further optimization. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  16. Selective Production of Aromatics from 2-Octanol on Zinc Ion-Exchanged MFI Zeolite Catalysts

    Directory of Open Access Journals (Sweden)

    Masakazu Iwamoto

    2015-12-01

    Full Text Available The aromatization of 2-octanol derived from castor oil as a byproduct in the formation of sebacic acid was investigated on various zeolite catalysts. Zn ion-exchanged MFI (ZSM-5 zeolites with small silica/alumina ratios and zinc contents of 0.5 to 2.0 wt. % were determined to exhibit good and stable activity for the reaction at 623 to 823 K. The yield of aromatics was 62% at 773 K and the space velocity 350 to 1400 h−1. The temperature and contact time dependences of the product distributions indicated the reaction pathways of 2-octanol→dehydration to 2-octene→decomposition to C5 and C3 compounds→further decomposition to small alkanes and alkenes→aromatization with dehydrogenation. Alcohols with carbon numbers of 5 to 8 exhibited similar distributions of products compared to 2-octanol, while corresponding carbonyl compounds demonstrated different reactivity.

  17. Irradiation of ethylene/styrene copolymers: evidence of sensitization of the aromatic moiety as counterpart of the radiation protection effect.

    Science.gov (United States)

    Ferry, M; Bessy, E; Harris, H; Lutz, P J; Ramillon, J-M; Ngono-Ravache, Y; Balanzat, E

    2012-02-16

    Molecules containing aromatics systems are more stable in the presence of ionizing radiations than alkanes. In the same way, introducing aromatic rings into aliphatic compounds increases their stability. The protective effect is nonlocal and likely results from the transfer of energy and species from the aliphatic moiety to the aromatic one. For years, it was commonly assumed that the aromatic moiety, which is very radiation resistant, accommodates the extra energy remaining unaffected. The use of Fourier transform infrared spectroscopy, online with high energy ion beam irradiation of ethylene/styrene random copolymers, allows us to bring experimental evidence that the benzene rings are sensitized by transfer reactions and consequently that this effect is more important in polymers with low benzene ring molar content.

  18. XVIII Mendeleev congress on general and applied chemistry. Summaries of reports in five volumes. Volume 5. IV Russian-French symposium Supramolecular systems in chemistry and biology. II Russian-Indian symposium on organic chemistry. International symposium on present-day radiochemistry Radiochemistry: progress and prospects. International symposium Green chemistry, stable evolution and social responsibility of chemists. Symposium Nucleophilic hydrogen substitution in aromatic systems and related reactions

    International Nuclear Information System (INIS)

    2007-01-01

    The 5 volume of the XVIII Mendeleev congress on general and applied chemistry includes summaries of reports on the subjects of sypramolecular systems in chemistry and biology, organic chemistry, modern radiochemistry, green chemistry - development and social responsibility of chemists, nucleophilic hydrogen substitution in aromatic systems and related chemical reactions [ru

  19. Stable isotopes labelled compounds

    International Nuclear Information System (INIS)

    1982-09-01

    The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

  20. Stable Boundary Layer Issues

    NARCIS (Netherlands)

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

  1. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    IAS Admin

    After Maynard-Smith and Price [1] mathematically derived why a given behaviour or strategy was adopted by a certain proportion of the population at a given time, it was shown that a strategy which is currently stable in a population need not be stable in evolutionary time (across generations). Additionally it was sug-.

  2. Aromatic claw: A new fold with high aromatic content that evades structural prediction: Aromatic Claw

    Energy Technology Data Exchange (ETDEWEB)

    Sachleben, Joseph R. [Biomolecular NMR Core Facility, University of Chicago, Chicago Illinois; Adhikari, Aashish N. [Department of Chemistry, University of Chicago, Chicago Illinois; Gawlak, Grzegorz [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Hoey, Robert J. [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Liu, Gaohua [Northeast Structural Genomics Consortium (NESG), Department of Molecular Biology and Biochemistry, School of Arts and Sciences, and Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, and Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway New Jersey; Joachimiak, Andrzej [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Biological Sciences Division, Argonne National Laboratory, Argonne Illinois; Montelione, Gaetano T. [Northeast Structural Genomics Consortium (NESG), Department of Molecular Biology and Biochemistry, School of Arts and Sciences, and Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, and Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway New Jersey; Sosnick, Tobin R. [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Koide, Shohei [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Department of Biochemistry and Molecular Pharmacology and the Perlmutter Cancer Center, New York University School of Medicine, New York New York

    2016-11-10

    We determined the NMR structure of a highly aromatic (13%) protein of unknown function, Aq1974 from Aquifex aeolicus (PDB ID: 5SYQ). The unusual sequence of this protein has a tryptophan content five times the normal (six tryptophan residues of 114 or 5.2% while the average tryptophan content is 1.0%) with the tryptophans occurring in a WXW motif. It has no detectable sequence homology with known protein structures. Although its NMR spectrum suggested that the protein was rich in β-sheet, upon resonance assignment and solution structure determination, the protein was found to be primarily α-helical with a small two-stranded β-sheet with a novel fold that we have termed an Aromatic Claw. As this fold was previously unknown and the sequence unique, we submitted the sequence to CASP10 as a target for blind structural prediction. At the end of the competition, the sequence was classified a hard template based model; the structural relationship between the template and the experimental structure was small and the predictions all failed to predict the structure. CSRosetta was found to predict the secondary structure and its packing; however, it was found that there was little correlation between CSRosetta score and the RMSD between the CSRosetta structure and the NMR determined one. This work demonstrates that even in relatively small proteins, we do not yet have the capacity to accurately predict the fold for all primary sequences. The experimental discovery of new folds helps guide the improvement of structural prediction methods.

  3. Hexacoordinate bonding and aromaticity in silicon phthalocyanine.

    Science.gov (United States)

    Yang, Yang

    2010-12-23

    Si-E bondings in hexacoordinate silicon phthalocyanine were analyzed using bond order (BO), energy partition, atoms in molecules (AIM), electron localization function (ELF), and localized orbital locator (LOL). Bond models were proposed to explain differences between hexacoordinate and tetracoordinate Si-E bondings. Aromaticity of silicon phthalocyanine was investigated using nucleus-independent chemical shift (NICS), harmonic oscillator model of aromaticity (HOMA), conceptual density functional theory (DFT), ring critical point (RCP) descriptors, and delocalization index (DI). Structure, energy, bonding, and aromaticity of tetracoordinate silicon phthalocyanine were studied and compared with hexacoordinate one.

  4. Conservation of medicinal and aromatic plants

    Directory of Open Access Journals (Sweden)

    Šveistytė, Laima

    2016-07-01

    Full Text Available The conservation of medicinal and aromatic plants includes ex situ and in situ methods. The genetic recourses of medicinal and aromatic plants are stored, studied and constantly maintained in the field collections of the Institute of Botany of Nature Research Centre, Kaunas Botanical Garden of Vytautas Magnus University and Aleksandras Stulginskis University of Agriculture. Presently seeds of 214 accessions representing 38 species of medicinal and aromatic plants are stored in a long-term storage in the Plant Gene Bank. The data about national genetic resources are collected and stored in the Central Database of the Plant Gene Bank.

  5. Co-Transport of Polycyclic Aromatic Hydrocarbons by Motile Microorganisms Leads to Enhanced Mass Transfer under Diffusive Conditions

    DEFF Research Database (Denmark)

    Gilbert, Dorthea; Jakobsen, Hans H.; Winding, Anne

    2014-01-01

    as sink and source for polycyclic aromatic hydrocarbons (PAHs). This resulted in stable concentration gradients in water (>24 h). Adding the model organism Tetrahymena pyriformis to the experimental system enhanced PAH mass transfer up to hundred-fold (benzo[a]pyrene). Increasing mass transfer enhancement...

  6. Synthesis and evaluation of aromaticity and tautomerization of ...

    Indian Academy of Sciences (India)

    Aromaticity of pyrazolopyridazin(on)es was investigated using NICS(0), NICS(1), NICSzz(1), FIPC-NICS and HOMA aromaticity indexes and it was observed that aromaticity of pyridazin(on)es was amenable to aromaticity of pyrazole and vice versa. Some tautomeric forms of pyridazinone were analyzedand the localized ...

  7. 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...

  8. Graphite Oxide and Aromatic Amines : Size Matters

    NARCIS (Netherlands)

    Spyrou, Konstantinos; Calvaresi, Matteo; Diamanti, Evmorfi A. K.; Tsoufis, Theodoros; Gournis, Dimitrios; Rudolf, Petra; Zerbetto, Francesco

    2015-01-01

    Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline

  9. International congress on aromatic and medicinal plants

    International Nuclear Information System (INIS)

    2009-01-01

    Full Text : In Morocco, medicinal and aromatic plants occupy an important place in the traditional care system of a large number of local people. They are also economically strong potential, but unfortunately they are not valued enough. Indeed, Morocco by its privileged geographical position in the Mediterranean basin and its floristic diversity (with a total of over 4,200 species and subspecies of which over 500 are recognized as medicinal and aromatic plants), is a leading provider of traditional global market. In this context and given the back label of the natural global, group research and studies on Aromatic and Medicinal Plants (GREPAM), the Faculty of Semlalia and University Cadi Ayyad, organize: the International Congress on Medicinal and Aromatic Plants CIPAM 2009. The organization of this conference is part of scientific research developed by the GREPAM. [fr

  10. Microbial transformation of chlorinated aromatics in sediments

    NARCIS (Netherlands)

    Beurskens, J.E.M.

    1995-01-01

    Numerous contaminants like heavy metals, polycyclic aromatic hydrocarbons (PAHs), chlorinated benzenes (CBs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo- p -dioxins (PCDDs) and polychlorinated furans (PCDFs) are detected in the major rivers in the

  11. Medicinally important aromatic plants with radioprotective activity.

    Science.gov (United States)

    Samarth, Ravindra M; Samarth, Meenakshi; Matsumoto, Yoshihisa

    2017-11-01

    Aromatic plants are often used as natural medicines because of their remedial and inherent pharmacological properties. Looking into natural resources, particularly products of plant origin, has become an exciting area of research in drug discovery and development. Aromatic plants are mainly exploited for essential oil extraction for applications in industries, for example, in cosmetics, flavoring and fragrance, spices, pesticides, repellents and herbal beverages. Although several medicinal plants have been studied to treat various conventional ailments only a handful studies are available on aromatic plants, especially for radioprotection. Many plant extracts have been reported to contain antioxidants that scavenge free radicals produced due to radiation exposure, thus imparting radioprotective efficacy. The present review focuses on a subset of medicinally important aromatic plants with radioprotective activity.

  12. Determination of carcinogenic polycyclic aromatic hydrocarbons ...

    African Journals Online (AJOL)

    Determination of carcinogenic polycyclic aromatic hydrocarbons (pahs), anthracene in different variety of fish samples in the Bangsai river of Bangladesh. F Yeasmin, SMM Rahman, S Rana, KJ Fatema, MA Hossain ...

  13. Normal modified stable processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2002-01-01

    This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...... Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process...

  14. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Letolle, R.; Mariotti, A.; Bariac, T.

    1991-06-01

    This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

  15. Aromaticity and relative stabilities of azines.

    Science.gov (United States)

    Wang, Yan; Wu, Judy I-Chia; Li, Qianshu; Schleyer, Paul von Ragué

    2010-11-05

    The most refined nucleus-independent chemical shift index (NICS(0)(πzz)) and the extra cyclic resonance energies (ECREs), based on the block localized wave function (BLW) method, show that the aromaticity of all azines is like that of benzene. The same is true for aza-naphthalenes relative to naphthalene. The lower relative energies of isomers with vicinal N's are due to the weakness of NN bonds rather than to reduced aromaticity.

  16. Aromatic Medicinal Plants from Tajikistan (Central Asia).

    Science.gov (United States)

    Sharopov, Farukh S; Zhang, Hanjing; Wink, Michael; Setzer, William N

    2015-02-17

    Tajikistan is a small country located in Central Asia. The mostly mountainous terrain with a continental, subtropical, and semiarid climate, is characterized by diverse flora. Many people in Tajikistan rely on medicinal plants as their traditional form of medicine to prevent and cure health disorders. Aromatic medicinal plants, in particular, have played an important role for the local people. In this review, we present a summary of the uses of 18 aromatic medicinal plants from Tajikistan and their compositions of secondary metabolites.

  17. Ionized polycyclic aromatic hydrocarbons and the diffuse interstellar bands

    International Nuclear Information System (INIS)

    Crawford, M.K.; Tielens, A.G.G.M.; Allamandola, L.J.

    1985-01-01

    A good case has recently been made that the unidentified infrared emission features arise from positively charged, partially hydrogenated polycyclic aromatic hydrocarbons (PAHs). In the Letter, we suggest that these exceedingly stable ions are also the carriers of the diffuse interstellar bands. Although a large variety of PAH isomers is possible, the more condensed forms are substantially more stable than the less condensed forms and are expected to be dominant in harsh interstellar environment. While neutral PAHs do not absorb in the visible, their ionized counterparts do. Because of their low ionization potential, a substantial fraction of the interstellar PAHs will be ionized. Visible spectra of the most stable PAH cations isolated in glasses are compared directly to the interstellar band spectra. Although the laboratory spectra are on an extremely compressed scale and solid state shifts are present, the comparison is favorable. Since little information is available concerning the spectroscopic properties of these species in the gas phase, a considerable amount of laboratory and theoretical work is called for to test this hypothesis

  18. Enantioselective synthesis of tricyclic amino acid derivatives based on a rigid 4-azatricyclo[5.2.1.02,6]decane skeleton

    Directory of Open Access Journals (Sweden)

    Matthias Breuning

    2009-12-01

    Full Text Available An enantioselective route to four tricyclic amino acids and N-tosylamides, composed of a central norbornane framework with a 2-endo,3-endo-annelated pyrrolidine ring and a 5-endo-C1 or -C2 side chain, has been developed. A key intermediate was the chiral, N-Boc-protected ketone (1R,2S,6S,7R-4-azatricyclo[5.2.1.02,6]decan-8-one, available from inexpensive endo-carbic anhydride in five steps and 47% yield. The rigid scaffold makes these amino acid derivatives promising candidates for β-turn-inducing building blocks in peptidomimetics and for chiral auxiliaries in asymmetric organocatalysis.

  19. Carbohydrate-Aromatic Interactions in Proteins.

    Science.gov (United States)

    Hudson, Kieran L; Bartlett, Gail J; Diehl, Roger C; Agirre, Jon; Gallagher, Timothy; Kiessling, Laura L; Woolfson, Derek N

    2015-12-09

    Protein-carbohydrate interactions play pivotal roles in health and disease. However, defining and manipulating these interactions has been hindered by an incomplete understanding of the underlying fundamental forces. To elucidate common and discriminating features in carbohydrate recognition, we have analyzed quantitatively X-ray crystal structures of proteins with noncovalently bound carbohydrates. Within the carbohydrate-binding pockets, aliphatic hydrophobic residues are disfavored, whereas aromatic side chains are enriched. The greatest preference is for tryptophan with an increased prevalence of 9-fold. Variations in the spatial orientation of amino acids around different monosaccharides indicate specific carbohydrate C-H bonds interact preferentially with aromatic residues. These preferences are consistent with the electronic properties of both the carbohydrate C-H bonds and the aromatic residues. Those carbohydrates that present patches of electropositive saccharide C-H bonds engage more often in CH-π interactions involving electron-rich aromatic partners. These electronic effects are also manifested when carbohydrate-aromatic interactions are monitored in solution: NMR analysis indicates that indole favorably binds to electron-poor C-H bonds of model carbohydrates, and a clear linear free energy relationships with substituted indoles supports the importance of complementary electronic effects in driving protein-carbohydrate interactions. Together, our data indicate that electrostatic and electronic complementarity between carbohydrates and aromatic residues play key roles in driving protein-carbohydrate complexation. Moreover, these weak noncovalent interactions influence which saccharide residues bind to proteins, and how they are positioned within carbohydrate-binding sites.

  20. Carbohydrate–Aromatic Interactions in Proteins

    Science.gov (United States)

    2015-01-01

    Protein–carbohydrate interactions play pivotal roles in health and disease. However, defining and manipulating these interactions has been hindered by an incomplete understanding of the underlying fundamental forces. To elucidate common and discriminating features in carbohydrate recognition, we have analyzed quantitatively X-ray crystal structures of proteins with noncovalently bound carbohydrates. Within the carbohydrate-binding pockets, aliphatic hydrophobic residues are disfavored, whereas aromatic side chains are enriched. The greatest preference is for tryptophan with an increased prevalence of 9-fold. Variations in the spatial orientation of amino acids around different monosaccharides indicate specific carbohydrate C–H bonds interact preferentially with aromatic residues. These preferences are consistent with the electronic properties of both the carbohydrate C–H bonds and the aromatic residues. Those carbohydrates that present patches of electropositive saccharide C–H bonds engage more often in CH−π interactions involving electron-rich aromatic partners. These electronic effects are also manifested when carbohydrate–aromatic interactions are monitored in solution: NMR analysis indicates that indole favorably binds to electron-poor C–H bonds of model carbohydrates, and a clear linear free energy relationships with substituted indoles supports the importance of complementary electronic effects in driving protein–carbohydrate interactions. Together, our data indicate that electrostatic and electronic complementarity between carbohydrates and aromatic residues play key roles in driving protein–carbohydrate complexation. Moreover, these weak noncovalent interactions influence which saccharide residues bind to proteins, and how they are positioned within carbohydrate-binding sites. PMID:26561965

  1. Analysing Stable Time Series

    National Research Council Canada - National Science Library

    Adler, Robert

    1997-01-01

    We describe how to take a stable, ARMA, time series through the various stages of model identification, parameter estimation, and diagnostic checking, and accompany the discussion with a goodly number...

  2. Management of chronic tension-type headache with tricyclic antidepressant medication, stress management therapy, and their combination: a randomized controlled trial.

    Science.gov (United States)

    Holroyd, K A; O'Donnell, F J; Stensland, M; Lipchik, G L; Cordingley, G E; Carlson, B W

    2001-05-02

    Chronic tension-type headaches are characterized by near-daily headaches and often are difficult to manage in primary practice. Behavioral and pharmacological therapies each appear modestly effective, but data are lacking on their separate and combined effects. To evaluate the clinical efficacy of behavioral and pharmacological therapies, singly and combined, for chronic tension-type headaches. Randomized placebo-controlled trial conducted from August 1995 to January 1998 at 2 outpatient sites in Ohio. Two hundred three adults (mean age, 37 years; 76% women) with diagnosis of chronic tension-type headaches (mean, 26 headache d/mo). Participants were randomly assigned to receive tricyclic antidepressant (amitriptyline hydrochloride, up to 100 mg/d, or nortriptyline hydrochloride, up to 75 mg/d) medication (n = 53), placebo (n = 48), stress management (eg, relaxation, cognitive coping) therapy (3 sessions and 2 telephone contacts) plus placebo (n = 49), or stress management therapy plus antidepressant medication (n = 53). Monthly headache index scores calculated as the mean of pain ratings (0-10 scale) recorded by participants in a daily diary 4 times per day; number of days per month with at least moderate pain (pain rating >/=5), analgesic medication use, and Headache Disability Inventory scores, compared by intervention group. Tricyclic antidepressant medication and stress management therapy each produced larger reductions in headache activity, analgesic medication use, and headache-related disability than placebo, but antidepressant medication yielded more rapid improvements in headache activity. Combined therapy was more likely to produce clinically significant (>/=50%) reductions in headache index scores (64% of participants) than antidepressant medication (38% of participants; P =.006), stress management therapy (35%; P =.003), or placebo (29%; P =.001). On other measures the combined therapy and its 2 component therapies produced similar outcomes. Our results

  3. Biosurfactant-enhanced bioremediation of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Cameotra, S.S.; Bollag, J.M. [Penn State University, University Park, PA (USA). Soil Biochemical Lab.

    2003-07-01

    Biosurfactants are surface-active compounds synthesized by it wide variety of micro-organisms. They are molecules that have both hydrophobic and hydrophilic domains and are capable of lowering the surface tension and the interfacial tension of the growth medium. Biosurfactants possess different chemical structures - lipopeptides, glycolipids, neutral lipids, and fatty acids. They are nontoxic biomolecules that are biodegradable. Biosurfactants also exhibit strong emulsification of hydrophobic compounds and form stable emulsions. Polycyclic aromatic hydrocarbons (PAHs) can be toxic, mutagenic, and carcinogenic compounds that pollute the environment. They are released to the environment its a result of spillage of oil and byproducts of coal treatment processes. The low water solubility of PAHs limits their availability to microorganisms, which is a potential problem for bioremediation of PAH-contaminated sites. Microbially produced surfactants enhance the bioavailability of these hydrophobic compounds for bioremediation. Therefore, biosurfactant-enhanced solubility of PAHs has potential applications in bioremediation.

  4. Direct, nonoxidative conversion of methane to ethylene, aromatics, and hydrogen.

    Science.gov (United States)

    Guo, Xiaoguang; Fang, Guangzong; Li, Gang; Ma, Hao; Fan, Hongjun; Yu, Liang; Ma, Chao; Wu, Xing; Deng, Dehui; Wei, Mingming; Tan, Dali; Si, Rui; Zhang, Shuo; Li, Jianqi; Sun, Litao; Tang, Zichao; Pan, Xiulian; Bao, Xinhe

    2014-05-09

    The efficient use of natural gas will require catalysts that can activate the first C-H bond of methane while suppressing complete dehydrogenation and avoiding overoxidation. We report that single iron sites embedded in a silica matrix enable direct, nonoxidative conversion of methane, exclusively to ethylene and aromatics. The reaction is initiated by catalytic generation of methyl radicals, followed by a series of gas-phase reactions. The absence of adjacent iron sites prevents catalytic C-C coupling, further oligomerization, and hence, coke deposition. At 1363 kelvin, methane conversion reached a maximum at 48.1% and ethylene selectivity peaked at 48.4%, whereas the total hydrocarbon selectivity exceeded 99%, representing an atom-economical transformation process of methane. The lattice-confined single iron sites delivered stable performance, with no deactivation observed during a 60-hour test.

  5. Gone or just out of sight? The apparent disappearance of aromatic litter components in soils

    Science.gov (United States)

    Klotzbücher, Thimo; Kalbitz, Karsten; Cerli, Chiara; Hernes, Peter J.; Kaiser, Klaus

    2016-07-01

    Uncertainties concerning stabilization of organic compounds in soil limit our basic understanding on soil organic matter (SOM) formation and our ability to model and manage effects of global change on SOM stocks. One controversially debated aspect is the contribution of aromatic litter components, such as lignin and tannins, to stable SOM forms. In the present opinion paper, we summarize and discuss the inconsistencies and propose research options to clear them. Lignin degradation takes place stepwise, starting with (i) depolymerization and followed by (ii) transformation of the water-soluble depolymerization products. The long-term fate of the depolymerization products and other soluble aromatics, e.g., tannins, in the mineral soils is still a mystery. Research on dissolved organic matter (DOM) composition and fluxes indicates dissolved aromatics are important precursors of stable SOM attached to mineral surfaces and persist in soils for centuries to millennia. Evidence comes from flux analyses in soil profiles, biodegradation assays, and sorption experiments. In contrast, studies on composition of mineral-associated SOM indicate the prevalence of non-aromatic microbial-derived compounds. Other studies suggest the turnover of lignin in soil can be faster than the turnover of bulk SOM. Mechanisms that can explain the apparent fast disappearance of lignin in mineral soils are, however, not yet identified. The contradictions might be explained by analytical problems. Commonly used methods probably detect only a fraction of the aromatics stored in the mineral soil. Careful data interpretation, critical assessment of analytical limitations, and combined studies on DOM and solid-phase SOM could thus be ways to unveil the issues.

  6. POLYCYCLIC AROMATIC HYDROCARBON FAR-INFRARED SPECTROSCOPY

    International Nuclear Information System (INIS)

    Boersma, C.; Mattioda, A. L.; Tielens, A. G. G. M.; Allamandola, L. J.; Bauschlicher, C. W. Jr; Ricca, A.; Peeters, E.

    2011-01-01

    The far-IR characteristics of astrophysically relevant polycyclic aromatic hydrocarbons (PAHs) averaging in size around 100 carbon atoms have been studied using the theoretical spectra in the NASA Ames PAH IR Spectroscopic Database. These spectra were calculated using density functional theory. Selections of PAH species are made, grouped together by common characteristics or trends, such as size, shape, charge, and composition, and their far-IR spectra compared. The out-of-plane modes involving the entire molecule are explored in detail, astronomical relevance is assessed, and an observing strategy is discussed. It is shown that PAHs produce richer far-IR spectra with increasing size. PAHs also produce richer far-IR spectra with increasing number of irregularities. However, series of irregular-shaped PAHs with the same compact core have common 'Jumping-Jack' modes that 'pile up' at specific frequencies in their average spectrum. For the PAHs studied here, around 100 carbon atoms in size, this band falls near 50 μm. PAH charge and nitrogen inclusion affect band intensities but have little effect on far-IR band positions. Detailed analysis of the two-dimensional, out-of-plane bending 'drumhead' modes in the coronene and pyrene 'families' and the one-dimensional, out-of-plane bending 'bar' modes in the acene 'family' show that these molecular vibrations can be treated as classical vibrating sheets and bars of graphene, respectively. The analysis also shows that the peak position of these modes is very sensitive to the area of the emitting PAH and does not depend on the particular geometry. Thus, these longest wavelength PAH bands could provide a unique handle on the size of the largest species in the interstellar PAH family. However, these bands are weak. Observing highly excited regions showing the mid-IR bands in which the emission from classical dust peaks at short wavelengths offers the best chance of detecting PAH emission in the far-IR. For these regions

  7. Spectroscopic Characterization of Key Aromatic and Heterocyclic Molecules: A Route toward the Origin of Life

    Science.gov (United States)

    Puzzarini, Cristina; Baiardi, Alberto; Bloino, Julien; Barone, Vincenzo; Murphy, Thomas E.; Drew, H. Dennis; Ali, Ashraf

    2017-09-01

    To gain information on the abiotic synthesis of the building blocks of life from simple molecules, and their subsequent chemical evolution to biological systems, the starting point is the identification of target species in Titan-like planets; I.e., planets that resemble the primitive Earth, as well as in Earth-like planets in the habitable zone of their star, namely planets where life can be already originated. In this scenario, molecular spectroscopy plays a crucial role because spectroscopic signatures are at the basis of an unequivocal proof for the presence of these target molecules. Thanks to advances in many different techniques and NASA’s successful Kepler exoplanet transit mission, thousands of diverse planets outside of our solar system have been discovered. The James Webb Space Telescope (JWST), scheduled to be launched in 2018, will be very helpful in the identification of biosignature gases in Earth-like planets’ atmospheres and prebiotic molecule signatures in Titan-like atmospheres, by observing their absorption during transits. Although the search for key-target molecules in exoplanet atmospheres can be carried out by the JWST Transit Spectroscopy in the infrared (IR) region (0.6-29 μm wavelength range), opportunities for their detection in protostellar cores, protoplanetary disks, and on Titan are also offered by interferometric high spectral and spatial resolution observations using the Atacama Large Millimeter/submillimeter Array. In the present work, target molecules have been selected, and their spectroscopic characterization presented in view of supporting their infrared and complementary millimeter/submillimeter-wave spectral observations. In detail, the selected target molecules include: (1) the three-membered oxygen-containing heterocycles, oxirane and protonated oxirane; (2) the cyclopropenyl cation and its methyl derivative; (3) two examples of ortho- and peri-fused tri-cyclic aromatic rings, I.e., the phenalenyl cation ({{{C}}}13

  8. Dibenzoheptazethrene isomers with different biradical characters: An exercise of clar's aromatic sextet rule in singlet biradicaloids

    KAUST Repository

    Sun, Zhe

    2013-12-04

    Clar\\'s aromatic sextet rule has been widely used for the prediction of the reactivity and stability of polycyclic aromatic hydrocarbons with a closed-shell electronic configuration. Recent advances in open-shell biradicaloids have shown that the number of aromatic sextet rings plays an important role in determination of their ground states. In order to test the validity of this rule in singlet biradicaloids, the two soluble and stable dibenzoheptazethrene isomers DBHZ1 and DBHZ2 were prepared by different synthetic approaches and isolated in crystalline form. These two molecules have different numbers of aromatic sextet rings in their respective biradical resonance forms and thus are expected to exhibit varied singlet biradical character. This assumption was verified by different experimental methods, including nuclear magnetic resonance (NMR), electron spin resonance (ESR), superconducting quantum interference device (SQUID), steady-state and transient absorption spectroscopy (TA), and X-ray crystallographic analysis, assisted by unrestricted symmetry-broken density functional theory (DFT) calculations. DBHZ2, with more aromatic sextet rings in the biradical form, was demonstrated to possess greater biradical character than DBHZ1; as a result, DBHZ2 exhibited an intense one-photon absorption (OPA) in the near-infrared region (λabs max = 804 nm) and a large two-photon absorption (TPA) cross-section (σ(2)max = 2800 GM at 1600 nm). This investigation together with previous studies indicates that Clar\\'s aromatic sextet rule can be further extended to the singlet biradicaloids to predict their ground states and singlet biradical characters. © 2013 American Chemical Society.

  9. C-H and N-H bond dissociation energies of small aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Barckholtz, C.; Barckholtz, T.A.; Hadad, C.M.

    1999-01-27

    A survey of computational methods was undertaken to calculate the homolytic bond dissociation energies (BDEs) of the C-H and N-H bonds in monocyclic aromatic molecules that are representative of the functionalities present in coal. These include six-membered rings (benzene, pyridine, pyridazine, pyrimidine, pyrazine) and five-membered rings (furan, thiophene, pyrrole, oxazole). By comparison of the calculated C-H BDEs with the available experimental values for these aromatic molecules, the B3LYP/6-31G(d) level of theory was selected to calculate the BDEs of polycyclic aromatic hydrocarbons (PAHs), including carbonaceous PAHs (naphthalene, anthracene, pyrene, coronene) and heteroatomic PAHs (benzofuran, benzothiophene, indole, benzoxazole, quinoline, isoquinoline, dibenzofuran, carbazole). The cleavage of a C-H or a N-H bond generates a {sigma} radical that is, in general, localized at the site from which the hydrogen atom was removed. However, delocalization of the unpaired electron results in {approximately} 7 kcal {center{underscore}dot} mol{sup {minus}1} stabilization of the radical with respect to the formation of phenyl when the C-H bond is adjacent to a nitrogen atom in the azabenzenes. Radicals from five-membered rings are {approximately} 6 kcal {center{underscore}dot} mol{sup {minus}1} less stable than those formed from six-membered rings due to both localization of the spin density and geometric factors. The location of the heteroatoms in the aromatic ring affects the C-H bond strengths more significantly than does the size of the aromatic network. Therefore, in general, the monocyclic aromatic molecules can be used to predict the C-H BDE of the large PAHs within 1 kcal {center{underscore}dot} mol{sup {minus}1}.

  10. Calcium stable isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

    2016-08-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  11. Chemotaxis of Azospirillum species to aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-de-Victoria, G.; Lovell, C.R. (Univ. of South Carolina, Columbia, SC (United States))

    1993-09-01

    Azospirillum sspeciesare free-living nitrogen fixing bacteria commonly found in soils and in association with plant roots, including important agricultural crops. Rhizosphere colonization my Azospirillum species has been shown to stimulate growth of a variety of plant species. Chemotaxis is one of the properties which may contribute to survival, rhizosphere colonization and the initiation of mutualistic interactions by Azospirillum species. This study evaluates the chemotactic responses of three Azospirillum stains to a variety of aromatic compounds:benzoate, catechol, 4-HB, and PCA. Results indicate that the same aromatic substance can elicit different chemotactic responses from different Azospirillum species, and that Azospirillum can detect aromatic substrates at concentrations similar to those they encounter naturally. 36 refs., 1 fig., 6 tabs.

  12. Ion beam irradiation effects on aromatic polymers

    International Nuclear Information System (INIS)

    Shukushima, Satoshi; Ueno, Keiji

    1995-01-01

    We studied the optical and thermal properties of aromatic polymer films which had been irradiated with 1 MeV H + , H 2 + and He + ions. The examined aromatic polymers were polyetherether ketone(PEEK), polyetherimide(PEI), polyether sulfon(PES), polysulfon(PSF), and polyphenylene sulfide(PPS). The optical densities at 300nm of PES and PSF greatly increased after the irradiation. The optical densities at 400nm of all the examined polymer lineally increased with the irradiation dose. The PEEK film which had been irradiated with 1 MeV H + was not deformed above melting point. This demonstrates that cross-linking occurs in PEEK films by ion beam irradiation. As for the effects, depending on the mass of the irradiated ions, it was found that the ions with a high mass induced larger effects on the aromatic polymers for the same absorption energy. (author)

  13. Spectrophotometric method for quantitative measuring essential oil in aromatic water and distillate with rose smell

    Science.gov (United States)

    Semenova, E.; Presnyakova, V.; Goncharov, D.; Goncharov, M.; Presnyakova, E.; Presnyakov, S.; Moiseeva, I.; Kolesnikova, S.

    2017-01-01

    In this connection, we improved the express methods of determining the mixture of volatile aromatic substances by the spectrophotometry of aromatic water and steam distillate of essential oil raw materials (traditional or biotechnological with rose smell). Direct spectrophotometry of distillation water is impossible because it is a colloid of liquid oil and law is not observed. Therefore, it is necessary to dissolve 1 ml of distillate in ethanol in the ratio 1:4, in this case we take real solution with no lipophilic fall-out on the walls of cuvette, also the light absorption law is observed. There are stable maximums in spectrums of studied oils. Optical density of these maximums is a result of summary absorption of terpenoid components (aromatic and monoterpene alcohols, its ethers). Optical density of tested and standard solutions is measured in appropriate wavelengths. Spectrophotometric method of determination of essential oil quantity in aromatic water with rose smell differs with high sensitivity (10-5-10-6 gmol/l) and allows to determine oil concentration from 0,900 to 0,008 mg with an error less than 1%. At that, 1 ml is enough for analysis. It’s expedient to apply this method while operating with small quantity of water distillate in biochemical and biotechnological researches and also as express control for extraction and hydrodistillation of essential oil raw material (rose petals and flowers from different origin, eremothecium cultural liquid etc.).

  14. Spectrophotometric method for quantitative measuring essential oil in aromatic water and distillate with rose smell

    International Nuclear Information System (INIS)

    Semenova, E; Moiseeva, I; Presnyakova, V; Goncharov, D; Goncharov, M; Presnyakova, E; Presnyakov, S; Kolesnikova, S

    2017-01-01

    In this connection, we improved the express methods of determining the mixture of volatile aromatic substances by the spectrophotometry of aromatic water and steam distillate of essential oil raw materials (traditional or biotechnological with rose smell). Direct spectrophotometry of distillation water is impossible because it is a colloid of liquid oil and law is not observed. Therefore, it is necessary to dissolve 1 ml of distillate in ethanol in the ratio 1:4, in this case we take real solution with no lipophilic fall-out on the walls of cuvette, also the light absorption law is observed. There are stable maximums in spectrums of studied oils. Optical density of these maximums is a result of summary absorption of terpenoid components (aromatic and monoterpene alcohols, its ethers). Optical density of tested and standard solutions is measured in appropriate wavelengths. Spectrophotometric method of determination of essential oil quantity in aromatic water with rose smell differs with high sensitivity (10 -5 -10 -6 gmol/l) and allows to determine oil concentration from 0,900 to 0,008 mg with an error less than 1%. At that, 1 ml is enough for analysis. It’s expedient to apply this method while operating with small quantity of water distillate in biochemical and biotechnological researches and also as express control for extraction and hydrodistillation of essential oil raw material (rose petals and flowers from different origin, eremothecium cultural liquid etc.). (paper)

  15. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 9. Evolutionary Stable Strategy: Application of Nash Equilibrium in Biology. General ... Using some examples of classical games, we show how evolutionary game theory can help understand behavioural decisions of animals.

  16. The Stable Concordance Genus

    OpenAIRE

    Kearney, M. Kate

    2013-01-01

    The concordance genus of a knot is the least genus of any knot in its concordance class. Although difficult to compute, it is a useful invariant that highlights the distinction between the three-genus and four-genus. In this paper we define and discuss the stable concordance genus of a knot, which describes the behavior of the concordance genus under connected sum.

  17. Manifolds admitting stable forms

    Czech Academy of Sciences Publication Activity Database

    Le, Hong-Van; Panák, Martin; Vanžura, Jiří

    2008-01-01

    Roč. 49, č. 1 (2008), s. 101-11 ISSN 0010-2628 R&D Projects: GA ČR(CZ) GP201/05/P088 Institutional research plan: CEZ:AV0Z10190503 Keywords : stable forms * automorphism groups Subject RIV: BA - General Mathematics

  18. Stable isotope studies

    International Nuclear Information System (INIS)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

  19. Interactive Stable Ray Tracing

    DEFF Research Database (Denmark)

    Dal Corso, Alessandro; Salvi, Marco; Kolb, Craig

    2017-01-01

    Interactive ray tracing applications running on commodity hardware can suffer from objectionable temporal artifacts due to a low sample count. We introduce stable ray tracing, a technique that improves temporal stability without the over-blurring and ghosting artifacts typical of temporal post-pr...

  20. The stable subgroup graph

    Directory of Open Access Journals (Sweden)

    Behnaz Tolue

    2018-07-01

    Full Text Available In this paper we introduce stable subgroup graph associated to the group $G$. It is a graph with vertex set all subgroups of $G$ and two distinct subgroups $H_1$ and $H_2$ are adjacent if $St_{G}(H_1\\cap H_2\

  1. Global aromatics supply. Today and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M. [BASF SE, Ludwigshafen (Germany)

    2013-11-01

    Aromatics are the essential building blocks for some of the largest petrochemical products in today's use. To the vast majority they are consumed to produce intermediates for polymer products and, hence, contribute to our modern lifestyle. Their growth rates are expected to be in line with GDP growth in future. This contrasts the significantly lower growth rates of the primary sources for aromatics - fuel processing and steam cracking of naphtha fractions. A supply gap can be expected to open up in future for which creative solutions will be required. (orig.)

  2. Three-dimensional aromaticity of polyhedral boranes

    International Nuclear Information System (INIS)

    Aihara, J.

    1978-01-01

    Resonance energies of typical polyhedral boranes with a general formula of B/sub n/H/sub n/ 2- have been calculated by means of a graph-theoretical theory of aromaticity previously reported by Aihara. Huckel-type molecular orbitals employed are those of Kettle and Tomlinson with three-center BBB localized orbitals as basis functions. Most polyhedral boranes investigated are predicted to be aromatic with positive resonance energies, in general agreement with their chemistry. The present resonance energy is fairly proportional to the logarithm of the number of valence structures allowed for the polyhedral borane

  3. Methods for the nitration of aromatic compounds

    OpenAIRE

    Smith, Keith; Alotaibi, Mohammad Hayal; El-Hiti, Gamal A.

    2012-01-01

    According to the invention there is provided a method for the nitration of an aromatic compound including the step of reacting the aromatic compound with nitric acid in the presence of an acid anhydride and an aluminosilicate catalyst, in which the acid anhydride is at least one of: ((CnH2n+1)CO)20, where n is 1 to 4 and the moiety CnH2n+1 can be straight or branched chain; ((CHpClq)CO)20, where p is 0 to 2, q is 1 to 3, and p+q = 3; and oxoiane -2, 5-dione, with the proviso that when the aci...

  4. Production of aromatics from di- and polyoxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

    2016-08-02

    Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Ni.sub.nSn.sub.m alloy and a crystalline alumina support.

  5. Production of aromatics from di- and polyoxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

    2016-09-13

    Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Group VIII metal and a crystalline alumina support.

  6. Production of aromatics from di- and polyoxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

    2017-07-04

    Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Ni.sub.nSn.sub.m alloy and a crystalline alumina support.

  7. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, R.E.; Dolbeare, F.A.

    1980-10-21

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 4-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes. No Drawings

  8. Imidazo[2,1-i]purin-5-ones and related tricyclic water-soluble purine derivatives: potent A(2A)- and A(3)-adenosine receptor antagonists.

    Science.gov (United States)

    Müller, Christa E; Thorand, Mark; Qurishi, Ramatullah; Diekmann, Martina; Jacobson, Kenneth A; Padgett, William L; Daly, John W

    2002-08-01

    A series of tricyclic imidazo[2,1-i]purinones and ring-enlarged analogues derived from xanthine derivatives have been prepared as adenosine receptor (AR) antagonists. In comparison with xanthines, the tricyclic compounds exhibit increased water solubility due to a basic nitrogen atom, which can be protonated under physiological conditions. Substituents were introduced that confer high affinity for A(2A) or A(3) ARs, respectively. A new capillary electrophoresis method was developed for the determination of the enantiomeric purity of selected chiral products using native and modified beta-cyclodextrins as chiral discriminators. The compounds were investigated in radioligand binding assays at rat brain A(1) and A(2A) ARs. Selected compounds were additionally investigated in radioligand binding assays at human recombinant A(3) ARs and in functional studies (adenylate cyclase assays) at A(1) ARs of rat fat cell membranes, A(2A) ARs of rat PC 12 cell membranes, and mouse A(2B) ARs of NIH 3T3 cell membranes. Structure-activity relationships were similar to those of corresponding xanthine derivatives. The 2-styrylimidazopurinones were less potent at A(2A) ARs as compared to 8-styrylxanthine derivatives. The most potent compound at A(2A) ARs was (S)-1,4-dimethyl-8-ethyl-2-styryl-imidazo[2,1-i]purinone (S-25) exhibiting a K(i) value of 424 nM at rat A(2A) ARs. The compound was highly selective for A(2A) receptors vs A(1) and A(3) ARs. Selectivity vs A(2B) ARs, however, was low. Among the 1-unsubstituted 2-phenyl-imidazo[2,1-i]purin-5-one derivatives, very potent and highly selective antagonists for human A(3) ARs were identified. The most potent A(3) antagonist of the present series was (R)-4-methyl-8-ethyl-2-phenyl-imidazo[2,1-i]purin-5-one (R-24) exhibiting a K(i) value of 2.3 nM and high selectivity for A(3) receptors vs all other AR subtypes.

  9. Stable isotope analysis

    International Nuclear Information System (INIS)

    Tibari, Elghali; Taous, Fouad; Marah, Hamid

    2014-01-01

    This report presents results related to stable isotopes analysis carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 127 samples. These results demonstrate that Oxygen-18 and Deuterium in water analysis were performed by infrared Laser spectroscopy using a LGR / DLT-100 with Autosampler. Also, the results are expressed in δ values (‰) relative to V-SMOW to ± 0.3 ‰ for oxygen-18 and ± 1 ‰ for deuterium.

  10. Forensic Stable Isotope Biogeochemistry

    Science.gov (United States)

    Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

    2016-06-01

    Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  11. Remediation of soil contaminated with polycyclic aromatic ...

    African Journals Online (AJOL)

    user

    2011-02-14

    Feb 14, 2011 ... adverse situations not only affect the ecosystem adver- sely as plant and animals may not survive, the crude may also contain varying levels of polycyclic aromatic hydrocarbons ..... Mechanism of phytoremediation: Biochemical and ecological interaction between plants and bacteria. Environ. Rev. 6: 65- 79.

  12. Toxic Potential of Carcinogenic Polycyclic Aromatic Hydrocarbons ...

    African Journals Online (AJOL)

    DR. GODSON

    Toxic Potential of Carcinogenic Polycyclic Aromatic Hydrocarbons (cPAHs) and Heavy. Metal in Crude Oil from Gokana Area, Rivers ... Exploration and production activities of petroleum in the Niger delta, Nigeria has led to the accidental ..... Chemical and bio-geophysical impact of four- dimensional seismic exploration.

  13. Polycyclic aromatic hydrocarbons (PAHs) contamination in coastal ...

    African Journals Online (AJOL)

    The objective of this study was to determine the levels of polycyclic aromatic hydrocarbons (PAHs) in sediments and crabs in the mangrove ecosystems of Zanzibar. Sediments and crabs from eight sampling sites were analysed for eleven selected PAHs. Samples were extracted with dichloromethane by ultrasonication, ...

  14. Determination of carcinogenic polycyclic aromatic hydrocarbons in ...

    African Journals Online (AJOL)

    Determination of carcinogenic polycyclic aromatic hydrocarbons in air samples in Irbid, north Jordan. A Al-Gawadreh Sat, M.B. Gasim, A.R. Hassan, A Azid. Abstract. Air samples were collected at an urban site and a rural (BERQESH) site during February (2017) until March (2017) to determine concentrations of polycyclic ...

  15. Measurements of Polycyclic Aromatic Hydrocarbons and ...

    African Journals Online (AJOL)

    ... with both fluorescence and ultraviolet detection. The genotoxicity was investigated by means of two bacterial assays: the Ames test and the SOS Chromotest. A number of PAHs were identified and genotoxic activity was observed in both of the assays. Keywords: Polycyclic aromatic hydrocarbons, toll plaza, genotoxicity.

  16. Fate and biodegradability of sulfonated aromatic amines

    NARCIS (Netherlands)

    Tan, N.C.G.; Leeuwen, van A.; Voorthuizen, van E.M.; Slenders, P.; Prenafeta, F.X.; Temmink, H.; Lettinga, G.; Field, J.A.

    2005-01-01

    Ten sulfonated aromatic amines were tested for their aerobic and anaerobic biodegradability and toxicity potential in a variety of environmental inocula. Of all the compounds tested, only two aminobenzenesulfonic acid (ABS) isomers, 2- and 4-ABS, were degraded. The observed degradation occurred only

  17. arene derivatives containing multiple aromatic groups

    Indian Academy of Sciences (India)

    ... two novel thiacalix[4]arene derivatives containing multiple aromatic groups in yields of 86% and 90%. Their complexation properties for four organic dyes were investigated by liquid-liquid extraction experiments, complexation UV-Vis spectra and mass spectrum. The highest extraction percentage was 97% for Neutral red.

  18. Determination of polynuclear aromatic hydrocarbons (PAHs) in ...

    African Journals Online (AJOL)

    Several water bodies in the Niger Delta region of Nigeria where extensive crude oil production activities take place were analyzed for the presence of 16 US EPA priority polynuclear aromatic hydrocarbons (PAHs) namely: naphthalene, acenaphthylene, acenaphthene, fluorine, phenanthrene, anthracene, fluoranthene, ...

  19. Adsorption of polynuclear aromatic hydrocarbons from aqueous

    African Journals Online (AJOL)

    ABSTRACT. The adsorption efficiency of a new hybrid clay adsorbent for polynuclear aromatic hydrocarbons. (PAHs) is compared with known modified clay adsorbents. The new hybrid clay adsorbent (HYCA) showed far higher adsorption capacities for the adsorption of various PAH molecules compared with sodium ...

  20. Predicting the Biodegradation of Polycyclic Aromatic Hydrocarbons ...

    African Journals Online (AJOL)

    ... the concentrations of the polycyclic aromatic hydrocarbons, and this was followed by a 'plateau' concentration signifying the attainment of endpoint of the degradation process. Keywords: Model, Neuron, Feed forward, Training, Input, Hidden and Output layers. Journal of the Nigerian Association of Mathematical Physics, ...

  1. Aromatic cytokinins in micropropagated potato plants

    Czech Academy of Sciences Publication Activity Database

    Baroja, F. E.; Aguirreolea, J.; Martínková, Hana; Hanuš, Jan; Strnad, Miroslav

    2002-01-01

    Roč. 40, č. 3 (2002), s. 217-224 ISSN 0981-9428 R&D Projects: GA MŠk OC 844.10; GA ČR GA301/02/0475 Institutional research plan: CEZ:AV0Z5038910 Keywords : Acclimatization * Aromatic cytokinins * Micropropagation Subject RIV: CE - Biochemistry Impact factor: 1.582, year: 2002

  2. Remediation of soil contaminated with polycyclic aromatic ...

    African Journals Online (AJOL)

    The aim of this study was to determine ways of remediating soils contaminated with polycyclic aromatic hydrocarbons (PAHs) associated with crude oil. The study involves the use of planted cowpeas, mushrooms, algae, dead vegetable and live earthworm, and fire-heating of the contaminated garden soil collected from the ...

  3. (Tpec) of Carcinogenic Polycyclic Aromatic Hydrocarbons (Cpahs)

    African Journals Online (AJOL)

    The aim of this paper is to report the determination of Total potency equivalent concentration (TPEC) of Carcinogenic polycyclic aromatic hydrocarbons (cPAHs) in soil samples from Bodo area in Ogoniland using the Toxicity Equivalent Factor (TEF) model. Gas Chromatography GC HP 5870 with FID was used for analysis.

  4. short communication aliphatic and polycyclic aromatic hydrocarbons ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. The impact of sunlight on aliphatic and polycyclic aromatic hydrocarbons profiles of Agbabu natural bitumen in Nigeria was investigated. The raw flow type of the bitumen was purified and exposed to sunlight for six consecutive months. Different portions of the bitumen were withdrawn at an interval of one.

  5. Polycyclic aromatic hydrocarbons (PAHs) degradation by laccase ...

    African Journals Online (AJOL)

    Laccase enzyme was produced from an isolate of the white rot fungus, Ganoderma lucidum Chaaim-001 BCU. The enzyme was subsequently evaluated for its degradative ability towards sixteen types of polycyclic aromatic hydrocarbons (PAHs). The G. lucidum laccase degraded antracene completely with or without a ...

  6. Fused aromatic thienopyrazines: structure, properties and function

    KAUST Repository

    Mondal, Rajib

    2010-01-01

    Recent development of a fused aromatic thieno[3.4-b]pyrazine system and their application in optoelectronic devices are reviewed. Introduction of a fused aromatic unit followed by side chain engineering, dramatically enhanced the charge carrier mobility in thin film transistor devices and mobilities up to 0.2 cm2/Vs were achieved. The optoelectronic properties of these fused aromatic thienopyrazine polymers (Eg = 1.3 to 1.6 eV, HOMO = -4.9 to -5.2 V) were tuned by introduction of various fused aromatic rings within thienopyrazine. By balancing the fundamental properties of these polymers, both high charge carrier mobilities and moderate PCEs in solar cells were achieved. Further, effects of copolymerizing units are discussed. Low band gap semiconducting polymer (Eg ∼ 1 eV) with high field effect mobility (0.044 cm2/Vs) was obtained using cyclopentadithiophene as copolymerizing unit. Finally, a molecular design approach to enhance the absorption coefficients is discussed, which resulted in improved power conversion efficiency in bulk heterojunction solar cells. © 2010 The Royal Society of Chemistry.

  7. Bioremediation of Polycyclic Aromatic Hydrocarbon contaminated ...

    African Journals Online (AJOL)

    This study investigates the effect of lead and chromium on the rate of bioremediation of polycyclic aromatic hydrocarbon (PAH) contaminated clay soil. Naphthalene was used as a target PAH. The soil was sterilized by heating at 120oC for one hour. 100g of the soil was contaminated with lead, chromium, nickel and mercury ...

  8. Synthesis and evaluation of aromaticity and tautomerization of ...

    Indian Academy of Sciences (India)

    Nurettin Menges

    FIPC-NICS and HOMA aromaticity indexes and it was observed that aromaticity of pyridazin(on)es was amenable to aromaticity of pyrazole and vice versa. Some tautomeric forms of pyridazinone were analyzed and the localized orbital locator maps, electron density maps, Fuzzy, Laplacian, and Mayer bond order methods.

  9. Aromatic oligoamides with a rare ortho-connectivity

    DEFF Research Database (Denmark)

    Hjelmgaard, T.; Nielsen, John

    2013-01-01

    Even though aromatic oligoamides composed of aromatic amino acids in a "one-way sequence" attract ever increasing research interest, backbones connected through ortho-linked aromatics remain rare. Herein, we present the first synthesis and study of N-alkylated ortho-aminomethyl- benzamides termed...

  10. Genetic diversity in grain quality and nutrition of aromatic rices

    African Journals Online (AJOL)

    STORAGESEVER

    2009-04-06

    Apr 6, 2009 ... The study was conducted at Bangladesh Rice Research Institute (BRRI), Gazipur in 2005 to assess the genetic divergence of aromatic rices for ... aromatic rices, requires its collection and evaluation of existing cultivars of ...... (2002). Genetic divergence in aromatic rice (Oryza sativa L). Nat. J. Plant Improv.

  11. 40 CFR 721.2673 - Aromatic epoxide resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic epoxide resin (generic). 721... Substances § 721.2673 Aromatic epoxide resin (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aromatic epoxide resin (PMN P...

  12. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic aldehyde phenolic resin... Specific Chemical Substances § 721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical substance... aromatic aldehyde phenolic resin (PMN P-01-573) is subject to reporting under this section for the...

  13. Stereoelectronic Effect-Induced Conductance Switching in Aromatic Chain Single-Molecule Junctions.

    Science.gov (United States)

    Xin, Na; Wang, Jinying; Jia, Chuancheng; Liu, Zitong; Zhang, Xisha; Yu, Chenmin; Li, Mingliang; Wang, Shuopei; Gong, Yao; Sun, Hantao; Zhang, Guanxin; Liu, Zhirong; Zhang, Guangyu; Liao, Jianhui; Zhang, Deqing; Guo, Xuefeng

    2017-02-08

    Biphenyl, as the elementary unit of organic functional materials, has been widely used in electronic and optoelectronic devices. However, over decades little has been fundamentally understood regarding how the intramolecular conformation of biphenyl dynamically affects its transport properties at the single-molecule level. Here, we establish the stereoelectronic effect of biphenyl on its electrical conductance based on the platform of graphene-molecule single-molecule junctions, where a specifically designed hexaphenyl aromatic chain molecule is covalently sandwiched between nanogapped graphene point contacts to create stable single-molecule junctions. Both theoretical and temperature-dependent experimental results consistently demonstrate that phenyl twisting in the aromatic chain molecule produces different microstates with different degrees of conjugation, thus leading to stochastic switching between high- and low-conductance states. These investigations offer new molecular design insights into building functional single-molecule electrical devices.

  14. Prenatal exposure to polycyclic aromatic hydrocarbons/aromatics, BDNF and child development.

    Science.gov (United States)

    Perera, Frederica; Phillips, David H; Wang, Ya; Roen, Emily; Herbstman, Julie; Rauh, Virginia; Wang, Shuang; Tang, Deliang

    2015-10-01

    Within a New York City (NYC) birth cohort, we assessed the associations between polycyclic aromatic hydrocarbon (PAH) and other aromatic DNA adducts and brain derived neurotrophic factor (BDNF) concentrations in umbilical cord blood, and neurodevelopment at age 2 years and whether BDNF is a mediator of the associations between PAH/aromatic-DNA adducts and neurodevelopment. PAH/aromatic-DNA adduct concentrations in cord blood were measured in 505 children born to nonsmoking African-American and Dominican women residing in NYC, and a subset was assessed for neurodevelopment at 2 years using the Bayley Scales of Infant Development Mental Development Index (MDI). A spectrum of PAH/aromatic-DNA adducts was measured using the (32)P-postlabeling assay; DNA adducts formed by benzo[a]pyrene (B[a]P), a representative PAH, were measured by High Performance Liquid Chromatography (HPLC)/fluorescence. BDNF mature protein in cord blood plasma was quantified by an ELISA. Multivariate regression analysis, adjusting for potential confounders, was conducted. PAH/aromatic-DNA adduct concentration measured by postlabeling was inversely associated with BDNF concentration (p=0.02) and with MDI scores at 2 years (p=0.04). BDNF level was positively associated with MDI scores (p=0.003). Restricting to subjects having all three measures (PAH/aromatic-DNA adducts by postlabeling, MDI, and BDNF), results were similar but attenuated (p=0.13, p=0.05, p=0.01, respectively). Associations between B[a]P-DNA adducts and BDNF and B[a]P-DNA adducts and MDI at age 2 years were not significant. At age 3 years, the positive association of BDNF with MDI was not observed. The results at age 2 suggest that prenatal exposure to a spectrum of PAH/aromatic pollutants may adversely affect early neurodevelopment, in part by reducing BDNF levels during the fetal period. However, the same relationship was not seen at age 3. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Push-pull vs captodative aromaticity.

    Science.gov (United States)

    Shainyan, Bagrat A; Fettke, Anja; Kleinpeter, Erich

    2008-10-30

    Vinylogs of fulvalenes with cyclopropenyl and cyclopentadienyl moieties attached either to different carbon atoms ( c-C 3H 2CHCHC 5H 4- c, 7) or to the same carbon atom [XC( c-C 3H 2)( c-C 5H 4), 10] [X = CH 2; C(CN) 2; C(NH 2) 2; C(OCH 2) 2; O; c-C 3H 2; c-C 5H 4; SiH 2; CCl 2] of the double bond inserted between the two rings are examined theoretically at the B3LYP/6-311G(d,p) level. Both types of compounds are shown to possess aromaticity, which was called "push-pull" and "captodative" aromaticity, respectively. For the captodative mesoionic structures XC( c-C 3H 2)( c-C 5H 4), the presence of both the two aromatic moieties and the CC double bond is the necessary and sufficient condition for their existence as energetic minima on the potential energy surface. Aromatic stabilization energy (ASE) was assessed by the use of homodesmotic reactions and heats of hydrogenation. Spatial magnetic criteria (through space NMR shieldings, TSNMRS) of the two types of vinylogous fulvalenes 7 and 10 have been calculated by the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept of Paul von Rague Schleyer, and visualized as iso-chemical-shielding surfaces (ICSS) of various sizes and directions. TSNMRS values can be successfully employed to visualize and quantify the partial push-pull and captodative aromaticity of both the three- and five-membered ring moieties. In addition, the push -pull effect in compounds 7 and 10 could be quantified by the occupation quotient pi* CC/pi CC of the double bond inserted between the two rings.

  16. HPLC and HPLC/MS/MS Studies on Stress, Accelerated and Intermediate Degradation Tests of Antivirally Active Tricyclic Analog of Acyclovir.

    Science.gov (United States)

    Lesniewska, Monika A; Dereziński, Paweł; Klupczyńska, Agnieszka; Kokot, Zenon J; Ostrowski, Tomasz; Zeidler, Joanna; Muszalska, Izabela

    2015-01-01

    The degradation behavior of a tricyclic analog of acyclovir [6-(4-MeOPh)-TACV] was determined in accordance with International Conference on Harmonization guidelines for good clinical practice under different stress conditions (neutral hydrolysis, strong acid/base degradation, oxidative decomposition, photodegradation, and thermal degradation). Accelerated [40±2°C/75%±5% relative humidity (RH)] and intermediate (30±2°C/65%±5% RH) stability tests were also performed. For observation of the degradation of the tested compound the RP-HPLC was used, whereas for the analysis of its degradation products HPLC/MS/MS was used. Degradation of the tested substance allowed its classification as unstable in neutral environment, acidic/alkaline medium, and in the presence of oxidizing agent. The tested compound was also light sensitive and was classified as photolabile both in solution and in the solid phase. However, the observed photodegradation in the solid phase was at a much lower level than in the case of photodegradation in solution. The study showed that both air temperature and RH had no significant effect on the stability of the tested substance during storage for 1 month at 100°C (dry heat) as well as during accelerated and intermediate tests. Based on the HPLC/MS/MS analysis, it can be concluded that acyclovir was formed as a degradation product of 6-(4-MeOPh)-TACV.

  17. Bio-inspired synthesis yields a tricyclic indoline that selectively resensitizes methicillin-resistant Staphylococcus aureus (MRSA) to β-lactam antibiotics.

    Science.gov (United States)

    Podoll, Jessica D; Liu, Yongxiang; Chang, Le; Walls, Shane; Wang, Wei; Wang, Xiang

    2013-09-24

    The continuous emergence of resistant bacteria has become a major worldwide health threat. The current development of new antibacterials has lagged far behind. To discover reagents to fight against resistant bacteria, we initiated a chemical approach by synthesizing and screening a small molecule library, reminiscent of the polycyclic indole alkaloids. Indole alkaloids are a class of structurally diverse natural products, many of which were isolated from plants that have been used as traditional medicine for millennia. Specifically, we adapted an evolutionarily conserved biosynthetic strategy and developed a concise and unified diversity synthesis pathway. Using this pathway, we synthesized 120 polycyclic indolines that contain 26 distinct skeletons and a wide variety of functional groups. A tricyclic indoline, Of1, was discovered to selectively potentiate the activity of β-lactam antibiotics in multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA), but not in methicillin-sensitive S. aureus. In addition, we found that Of1 itself does not have antiproliferative activity but can resensitize several MRSA strains to the β-lactam antibiotics that are widely used in the clinic, such as an extended-spectrum β-lactam antibiotic amoxicillin/clavulanic acid and a first-generation cephalosporin cefazolin. These data suggest that Of1 is a unique selective resistance-modifying agent for β-lactam antibiotics, and it may be further developed to fight against resistant bacteria in the clinic.

  18. Comparative study of cognitive impairment between medicated and medication-free patients with remitted major depression: class-specific influence by tricyclic antidepressants and newer antidepressants.

    Science.gov (United States)

    Nagane, Akiko; Baba, Hajime; Nakano, Yoshiyuki; Maeshima, Hitoshi; Hukatsu, Mana; Ozawa, Kazuhiro; Suzuki, Toshihito; Arai, Heii

    2014-08-15

    Patients with major depressive disorder (MDD) are known to present with cognitive deficits; however, the presence of these deficits in the remitted state have been inconsistent. One of the most important factors potentially contributing to inconsistencies between studies may be the influence of medications. To explore the influence of antidepressants on cognitive performance in remitted MDD, we evaluated memory and executive functions using Wechsler Memory Scale-Revised and Stroop Color and Word Test, and compared performance among 50 medicated (29 treated with tricyclic antidepressants [TCA], 21 treated with selective serotonin reuptake inhibitors or serotonin noradrenalin reuptake inhibitors) and 19 medication-free MDD patients and 31 controls. The results showed that all 3 MDD groups had significantly lower performance for verbal memory compared with controls. Both medicated groups showed significantly lower performance for visual memory compared with controls; however, the medication-free group did not differ from controls. For the executive function, only the TCA group showed a significantly lower performance compared with controls. These results suggest that cognitive impairment remained even in remitted patients with MDD, however, part of this impairment may be influenced by class-specific antidepressant side effects. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Combination of electromembrane extraction with dispersive liquid-liquid microextraction followed by gas chromatographic analysis as a fast and sensitive technique for determination of tricyclic antidepressants.

    Science.gov (United States)

    Seidi, Shahram; Yamini, Yadollah; Rezazadeh, Maryam

    2013-01-15

    For the first time, combination of electromembrane extraction (EME) and dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-flame ionization detection (GC/FID) was developed for determination of tricyclic antidepressants (TCAs) in untreated human plasma and urine samples. Response surface methodology (RSM) was used for optimization of experimental parameters, so that extraction time of 14min, voltage of 240V, donor phase of 64mM HCl and acceptor phase of 100mM HCl were obtained as optimal extraction conditions. Matrix effect and carry-over were investigated in this work. The results indicated matrix effect for urine and plasma samples in comparison with neat solutions, so match matrix method was used for drawing working calibration curves. However, no carry-over was appeared at the retention time of investigated TCAs (S/N86.5%. The results showed that EME-DLLME-GC/FID is a promising combination for analysis of TCAs present at low concentrations in biological matrices. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Parsing of the free energy of aromatic-aromatic stacking interactions in solution

    Energy Technology Data Exchange (ETDEWEB)

    Kostjukov, Viktor V.; Khomytova, Nina M. [Department of Physics, Sevastopol National Technical University, Sevastopol 99053, Crimea (Ukraine); Hernandez Santiago, Adrian A.; Tavera, Anna-Maria Cervantes; Alvarado, Julieta Salas [Faculty of Chemical Sciences, Autonomous University of Puebla, Puebla (Mexico); Evstigneev, Maxim P., E-mail: max_evstigneev@mail.ru [Department of Physics, Sevastopol National Technical University, Sevastopol 99053, Crimea (Ukraine)

    2011-10-15

    Graphical abstract: Highlights: > A protocol for decomposition of the free energy of aromatic stacking is developed. > The factors stabilizing/destabilizing stacking of aromatic molecules are defined. > Hydrophobic contribution is found to be dominant. - Abstract: We report an analysis of the energetics of aromatic-aromatic stacking interactions for 39 non-covalent reactions of self- and hetero-association of 12 aromatic molecules with different structures and charge states. A protocol for computation of the contributions to the total energy from various energetic terms has been developed and the results are consistent with experiment in 92% of all the systems studied. It is found that the contributions from hydrogen bonds and entropic factors are always unfavorable, whereas contributions from van-der-Waals, electrostatic and/or hydrophobic effects may lead to stabilizing or destabilizing factors depending on the system studied. The analysis carried out in this work provides an answer to the questions 'What forces stabilize/destabilize the stacking of aromatic molecules in aqueous-salt solution and what are their relative importance?'

  1. Parsing of the free energy of aromatic-aromatic stacking interactions in solution

    International Nuclear Information System (INIS)

    Kostjukov, Viktor V.; Khomytova, Nina M.; Hernandez Santiago, Adrian A.; Tavera, Anna-Maria Cervantes; Alvarado, Julieta Salas; Evstigneev, Maxim P.

    2011-01-01

    Graphical abstract: Highlights: → A protocol for decomposition of the free energy of aromatic stacking is developed. → The factors stabilizing/destabilizing stacking of aromatic molecules are defined. → Hydrophobic contribution is found to be dominant. - Abstract: We report an analysis of the energetics of aromatic-aromatic stacking interactions for 39 non-covalent reactions of self- and hetero-association of 12 aromatic molecules with different structures and charge states. A protocol for computation of the contributions to the total energy from various energetic terms has been developed and the results are consistent with experiment in 92% of all the systems studied. It is found that the contributions from hydrogen bonds and entropic factors are always unfavorable, whereas contributions from van-der-Waals, electrostatic and/or hydrophobic effects may lead to stabilizing or destabilizing factors depending on the system studied. The analysis carried out in this work provides an answer to the questions 'What forces stabilize/destabilize the stacking of aromatic molecules in aqueous-salt solution and what are their relative importance?'

  2. Hydrothermally generated aromatic compounds are consumed by bacteria colonizing in Atlantis II Deep of the Red Sea

    KAUST Repository

    Wang, Yong

    2011-04-28

    Hydrothermal ecosystems have a wide distribution on Earth and many can be found in the basin of the Red Sea. Production of aromatic compounds occurs in a temperature window of 60-150 °C by utilizing organic debris. In the past 50 years, the temperature of the Atlantis II Deep brine pool in the Red Sea has increased from 56 to 68 °C, whereas the temperature at the nearby Discovery Deep brine pool has remained relatively stable at about 44 °C. In this report, we confirmed the presence of aromatic compounds in the Atlantis II brine pool as expected. The presence of the aromatic compounds might have disturbed the microbes in the Atlantis II. To show shifted microbial communities and their metabolisms, we sequenced the metagenomes of the microbes from both brine pools. Classification based on metareads and the 16S rRNA gene sequences from clones showed a strong divergence of dominant bacterial species between the pools. Bacteria capable of aromatic degradation were present in the Atlantis II brine pool. A comparison of the metabolic pathways showed that several aromatic degradation pathways were significantly enriched in the Atlantis II brine pool, suggesting the presence of aromatic compounds. Pathways utilizing metabolites derived from aromatic degradation were also significantly affected. In the Discovery brine pool, the most abundant genes from the microbes were related to sugar metabolism pathways and DNA synthesis and repair, suggesting a different strategy for the utilization of carbon and energy sources between the Discovery brinse pool and the Atlantis II brine pool. © 2011 International Society for Microbial Ecology. All rights reserved.

  3. Aromatic Structure in Simulates Titan Aerosol

    Science.gov (United States)

    Trainer, Melissa G.; Loeffler, M. J.; Anderson, C. M.; Hudson, R. L.; Samuelson, R. E.; Moore, M. A.

    2011-01-01

    Observations of Titan by the Cassini Composite Infrared Spectrometer (CIRS) between 560 and 20 per centimeter (approximately 18 to 500 micrometers) have been used to infer the vertical variations of Titan's ice abundances, as well as those of the aerosol from the surface to an altitude of 300 km [1]. The aerosol has a broad emission feature centered approximately at 140 per centimeter (71 micrometers). As seen in Figure 1, this feature cannot be reproduced using currently available optical constants from laboratory-generated Titan aerosol analogs [2]. The far-IR is uniquely qualified for investigating low-energy vibrational motions within the lattice structures of COITIDlex aerosol. The feature observed by CIRS is broad, and does not likely arise from individual molecules, but rather is representative of the skeletal movements of macromolecules. Since Cassini's arrival at Titan, benzene (C6H6) has been detected in the atmosphere at ppm levels as well as ions that may be polycyclic aromatic hydrocarbons (PAHs) [3]. We speculate that the feature may be a blended composite that can be identified with low-energy vibrations of two-dimensional lattice structures of large molecules, such as PAHs or nitrogenated aromatics. Such structures do not dominate the composition of analog materials generated from CH4 and N2 irradiation. We are performing studies forming aerosol analog via UV irradiation of aromatic precursors - specifically C6H6 - to understand how the unique chemical architecture of the products will influence the observable aerosol characteristics. The optical and chemical properties of the aromatic analog will be compared to those formed from CH4/N2 mixtures, with a focus on the as-yet unidentified far-IR absorbance feature. Preliminary results indicate that the photochemically-formed aromatic aerosol has distinct chemical composition, and may incorporate nitrogen either into the ring structure or adjoined chemical groups. These compositional differences are

  4. Silicone elastomers with aromatic voltage stabilizers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Skov, Anne Ladegaard

    A method to synthesise a polydimethylsiloxane-polyphenylmethylsiloxane (PDMS-PPMS) copolymer with electron-trapping effects has been developed utilising a quickhydrosilylation reaction at ambient temperature and crosslinking via hydrosilylation by a vinyl-functional crosslinker. The mechanism...... of electron-trapping by aromatic compounds grafted to silicone backbones in a crosslinked PDMS is illustrated in Fig. 1. The electrical breakdown strength, the storage modulus and the loss modulus of the elastomer were investigated, as well as the excitation energy from the collision between electron carriers...... and benzene rings in PDMS-PPMS copolymer was measured by UV-vis spectroscopy. The developed elastomers were inherently soft with enhanced electrical breakdown strength due to delocalized pi-electrons of aromatic rings attached to the silicone backbone. The dielectric relative permittivity of PDMS...

  5. Detecting the building blocks of aromatics

    Science.gov (United States)

    Joblin, Christine; Cernicharo, José

    2018-01-01

    Interstellar clouds are sites of active organic chemistry (1). Many small, gasphase molecules are found in the dark parts of the clouds that are protected from ultraviolet (UV) photons, but these molecules photodissociate in the external layers of the cloud that are exposed to stellar radiation (see the photo). These irradiated regions are populated by large polycyclic aromatic hydrocarbons (PAHs) with characteristic infrared (IR) emission features. These large aromatics are expected to form from benzene (C6H6), which is, however, difficult to detect because it does not have a permanent dipole moment and can only be detected via its IR absorption transitions against a strong background source (2). On page 202 of this issue, McGuire et al. (3) report the detection of benzonitrile (c-C6H5CN) with radio telescopes. Benzonitrile likely forms in the reaction of CN with benzene; from its observation, it is therefore possible to estimate the abundance of benzene itself.

  6. Marginally Stable Nuclear Burning

    Science.gov (United States)

    Strohmayer, Tod E.; Altamirano, D.

    2012-01-01

    Thermonuclear X-ray bursts result from unstable nuclear burning of the material accreted on neutron stars in some low mass X-ray binaries (LMXBs). Theory predicts that close to the boundary of stability oscillatory burning can occur. This marginally stable regime has so far been identified in only a small number of sources. We present Rossi X-ray Timing Explorer (RXTE) observations of the bursting, high- inclination LMXB 4U 1323-619 that reveal for the first time in this source the signature of marginally stable burning. The source was observed during two successive RXTE orbits for approximately 5 ksec beginning at 10:14:01 UTC on March 28, 2011. Significant mHz quasi- periodic oscillations (QPO) at a frequency of 8.1 mHz are detected for approximately 1600 s from the beginning of the observation until the occurrence of a thermonuclear X-ray burst at 10:42:22 UTC. The mHz oscillations are not detected following the X-ray burst. The average fractional rms amplitude of the mHz QPOs is 6.4% (3 - 20 keV), and the amplitude increases to about 8% below 10 keV.This phenomenology is strikingly similar to that seen in the LMXB 4U 1636-53. Indeed, the frequency of the mHz QPOs in 4U 1323-619 prior to the X-ray burst is very similar to the transition frequency between mHz QPO and bursts found in 4U 1636-53 by Altamirano et al. (2008). These results strongly suggest that the observed QPOs in 4U 1323-619 are, like those in 4U 1636-53, due to marginally stable nuclear burning. We also explore the dependence of the energy spectrum on the oscillation phase, and we place the present observations within the context of the spectral evolution of the accretion-powered flux from the source.

  7. Hydrocarbon fractions. Aromatic determination by mass spectrometry

    International Nuclear Information System (INIS)

    Anon.

    Analysis of hydrocarbon fractions by mass spectrometry using low energy electrons, for determination of aromatic hydrocarbons repartition, suitable for fraction with the following properties: boiling point up to 320 0 C, whithout olefine, sulfur content up to 0.1 per cent, boiling range up to 100 0 C, if the final temperature is 200 0 C, and up to 50 0 C, if over 200 0 C [fr

  8. Aromatic compounds from three Brazilian Lauraceae species

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Andrea Nastri de Luca; Batista Junior, Joao Marcos; Lopez, Silvia Noeli; Furlan, Maysa; Cavalheiro, Alberto Jose; Silva, Dulce Helena Siqueira; Bolzani, Vanderlan da Silva [UNESP, Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Nunomura, Sergio Massayoshi [Instituto Nacional de Pesquisa da Amazonia (INPA), Manaus, AM (Brazil). Dept. de Produtos Naturais; Yoshida, Massayoshi [Centro de Biotecnologia da Amazonia, Manaus, AM (Brazil)

    2010-07-01

    Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of Sao Paulo State, Ocotea corymbosa (Meins) Mez., O. elegans Mez. and Persea pyrifolia Nees and Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia. (author)

  9. Aromatic compounds from three Brazilian Lauraceae species

    International Nuclear Information System (INIS)

    Batista, Andrea Nastri de Luca; Batista Junior, Joao Marcos; Lopez, Silvia Noeli; Furlan, Maysa; Cavalheiro, Alberto Jose; Silva, Dulce Helena Siqueira; Bolzani, Vanderlan da Silva

    2010-01-01

    Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of Sao Paulo State, Ocotea corymbosa (Meins) Mez., O. elegans Mez. and Persea pyrifolia Nees and Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia. (author)

  10. Transformations of aromatic hydrocarbons over zeolites

    Czech Academy of Sciences Publication Activity Database

    Voláková, Martina; Žilková, Naděžda; Čejka, Jiří

    2008-01-01

    Roč. 34, 5-7 (2008), s. 439-454 ISSN 0922-6168 R&D Projects: GA ČR GA203/05/0197; GA AV ČR 1QS400400560; GA AV ČR KJB4040402 Institutional research plan: CEZ:AV0Z40400503 Keywords : aromatic hydrocarbons * zeolites * alkylation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.514, year: 2008

  11. Aromatics Oxidation and Soot Formation in Flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J. B.; Richter, H.

    2005-03-29

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and the growth process to polycyclic aromatic hydrocarbons (PAH) of increasing size, soot and fullerenes formation in flames. The overall objective of the experimental aromatics oxidation work is to extend the set of available data by measuring concentration profiles for decomposition intermediates such as phenyl, cyclopentadienyl, phenoxy or indenyl radicals which could not be measured with molecular-beam mass spectrometry to permit further refinement and testing of benzene oxidation mechanisms. The focus includes PAH radicals which are thought to play a major role in the soot formation process while their concentrations are in many cases too low to permit measurement with conventional mass spectrometry. The radical species measurements are used in critical testing and improvement of a kinetic model describing benzene oxidation and PAH growth. Thermodynamic property data of selected species are determined computationally, for instance using density functional theory (DFT). Potential energy surfaces are explored in order to identify additional reaction pathways. The ultimate goal is to understand the conversion of high molecular weight compounds to nascent soot particles, to assess the roles of planar and curved PAH and relationships between soot and fullerenes formation. The specific aims are to characterize both the high molecular weight compounds involved in the nucleation of soot particles and the structure of soot including internal nanoscale features indicative of contributions of planar and/or curved PAH to particle inception.

  12. The unique aromatic catabolic genes in sphingomonads degrading polycyclic aromatic hydrocarbons (PAHs).

    Science.gov (United States)

    Pinyakong, Onruthai; Habe, Hiroshi; Omori, Toshio

    2003-02-01

    Many members of the sphingomonad genus isolated from different geological areas can degrade a wide variety of polycyclic aromatic hydrocarbons (PAHs) and related compounds. These sphingomonads such as Sphingobium yanoikuyae strain B1, Novosphingobium aromaticivorans strain F199, and Sphingobium sp. strain P2 have been found to possess a unique group of genes for aromatic degradation, which are distantly related with those in pseudomonads and other genera reported so far both in sequence homology and gene organization. Genes for aromatics degradation in these sphingomonads are complexly arranged; the genes necessary for one degradation pathway are scattered through several clusters. These aromatic catabolic gene clusters seem to be conserved among many other sphingomonads such as Sphingobium yanoikuyae strain Q1, Sphingomonas paucimobilis strain TNE12, S. paucimobilis strain EPA505, Sphingobium agrestis strain HV3, and Sphingomonas chungbukensis strain DJ77. Furthermore, some genes for naphthalenesulfonate degradation found in Sphingomonas xenophaga strain BN6 also share a high sequence homology with their homologues found in these sphingomonads. On the other hand, protocatechuic catabolic gene clusters found in fluorene-degrading Sphingomonas sp. strain LB126 appear to be more closely related with those previously found in lignin-degrading S. paucimobilis SYK-6 than the genes in this group of sphingomonads. This review summarizes the information on the distribution of these strains and relationships among their aromatic catabolic genes.

  13. Fengabine, a new GABAmimetic agent in the treatment of depressive disorders: an overview of six double-blind studies versus tricyclics.

    Science.gov (United States)

    Magni, G; Garreau, M; Orofiamma, B; Palminteri, R

    1989-01-01

    Fengabine is a new GABAmimetic compound active in animal models predictive of antidepressant activity. The present overview reports the results of 6 double-blind trials versus tricyclics (TCAs) (3 in outpatients and 3 in inpatients). Overall, 398 adult patients (149 males and 249 females) were treated; 194 with fengabine and 204 with TCAs (98 clomipramine, 63 amitriptyline and 43 imipramine). 284 suffered from major depression (MD) (including major depressive disorder and bipolar disorder, depressed; DSM III) and 114 from minor depression (MiD) including dysthymic disorder, atypical depression and adjustment disorder with depressive mood (DSM III). Dosage ranged from 600 to 2,400 mg/day for fengabine and 50 to 200 mg/day for TCAs. Efficacy was evaluated with the HAM-D scale. 311 subjects (154 fengabine and 157 TCAs) ended the 4-week treatment period. Considering the whole sample and mean IAM-D scores, no significant differences emerged between the 2 treatment groups at any of the assessment periods. Because of a significant treatment x type of depression interaction, MD and MiD were analysed separately, and a different trend appeared in the 2 subgroups with TCAs behaving slightly better than fengabine in MD and fengabine performing slightly better than TCAs in MiD. Using the physician's clinical improvement, 74% of patients under fengabine and 72% of those under TCAs were rated as improved or much improved. Side effects, particularly of the anticholinergic type were significantly more frequent in the TCAs group. Gamma-GT were more frequently altered in the fengabine group (30.4 vs. 10.5%); this increase was interpreted as a consequence of enzymatic induction. Lastly, more patients taking fengabine exhibited an increase in cholesterol values.

  14. Development of new extraction method based on liquid-liquid-liquid extraction followed by dispersive liquid-liquid microextraction for extraction of three tricyclic antidepressants in plasma samples.

    Science.gov (United States)

    Farajzadeh, Mir Ali; Abbaspour, Maryam

    2018-03-27

    In the present study, a new extraction method based on a three-phase system liquid-liquid-liquid extraction followed by dispersive liquid-liquid microextraction has been developed and validated for the extraction and preconcentration of three commonly prescribed tricyclic antidepressant drugs including amitriptyline, imipramine, and clomipramine in human plasma prior to their analysis by gas chromatography-flame ionization detection. Three phases are an aqueous phase (plasma), acetonitrile, and n-hexane. The extraction mechanism is based on the different affinities of components of the biological sample (lipids, fatty acids, pharmaceuticals, inorganic ions, etc.) towards each of the involved phase. This provides high selectivity towards the analytes since most interferences are transferred into n-hexane. In this procedure, a homogeneous solution of the aqueous phase (plasma) and acetonitrile (water-soluble extraction solvent) is broken by adding sodium sulfate (as a phase separating agent) and the analytes are extracted into the fine droplets of the formed acetonitrile. In the following, acetonitrile phase is mixed with 1,2-dibromoethane (as a preconcentration solvent at μL-level) and then the microextraction procedure mentioned above is performed for further enrichment of the analytes. Under the optimum extraction conditions, limits of detection and lower limits of quantification for the analytes were obtained in the ranges of 0.001-0.003 and 0.003-0.010 μg mL -1 , respectively. The obtained extraction recoveries were in the range of 79-98%. Intra- and inter-day precisions were less than 7.5%. The validated method was successfully applied for determination of the selected drugs in human plasma samples obtained from the patients who received them. This article is protected by copyright. All rights reserved.

  15. Metabolism and Biomarkers of Heterocyclic Aromatic Amines in Molecular Epidemiology Studies: Lessons Learned from Aromatic Amines

    Science.gov (United States)

    2011-01-01

    Aromatic amines and heterocyclic aromatic amines (HAAs) are structurally related classes of carcinogens that are formed during the combustion of tobacco or during the high-temperature cooking of meats. Both classes of procarcinogens undergo metabolic activation by N-hydroxylation of the exocyclic amine group, to produce a common proposed intermediate, the arylnitrenium ion, which is the critical metabolite implicated in toxicity and DNA damage. However, the biochemistry and chemical properties of these compounds are distinct and different biomarkers of aromatic amines and HAAs have been developed for human biomonitoring studies. Hemoglobin adducts have been extensively used as biomarkers to monitor occupational and environmental exposures to a number of aromatic amines; however, HAAs do not form hemoglobin adducts at appreciable levels and other biomarkers have been sought. A number of epidemiologic studies that have investigated dietary consumption of well-done meat in relation to various tumor sites reported a positive association between cancer risk and well-done meat consumption, although some studies have shown no associations between well-done meat and cancer risk. A major limiting factor in most epidemiological studies is the uncertainty in quantitative estimates of chronic exposure to HAAs and, thus, the association of HAAs formed in cooked meat and cancer risk has been difficult to establish. There is a critical need to establish long-term biomarkers of HAAs that can be implemented in molecular epidemioIogy studies. In this review article, we highlight and contrast the biochemistry of several prototypical carcinogenic aromatic amines and HAAs to which humans are chronically exposed. The biochemical properties and the impact of polymorphisms of the major xenobiotic-metabolizing enzymes on the biological effects of these chemicals are examined. Lastly, the analytical approaches that have been successfully employed to biomonitor aromatic amines and HAAs, and

  16. Synthesis of Bio-aromatics from Black Liquors Using Catalytic Pyrolysis

    Science.gov (United States)

    2018-01-01

    Bio-aromatics (benzene, toluene, xylenes, BTX) were prepared by the catalytic pyrolysis of six different black liquors using both in situ and ex situ approaches. A wide range of catalysts was screened and conditions were optimized in microscale reactors. Up to 7 wt % of BTX, based on the organic fraction of the black liquors, was obtained for both the in situ and ex situ pyrolysis (T = 500–600 °C) using a Ga-modified H-ZSM-5 catalyst. The in situ catalytic pyrolysis of black liquors from hardwood paper mills afforded slightly higher yields of aromatics/BTX than softwood black liquors, a trend that could be confirmed by the results obtained in the ex situ catalytic pyrolysis. An almost full deoxygenation of the lignin and carbohydrate fraction was achieved and both organic fractions were converted to a broad range of (substituted) aromatics. The zeolite catalyst used was remarkably stable and even after 100 experiments in batch mode with intermittent oxidative catalyst regeneration, the yields and selectivity toward BTX remained similar. The ex situ pyrolysis of black liquor has potential for large-scale implementation in a paper mill without disturbing the paper production process. PMID:29607268

  17. Polynuclear Aromatic Hydrocarbons with Curved Surfaces: Buckyballs

    Energy Technology Data Exchange (ETDEWEB)

    Sygula, Andrzej [Mississippi State Univ., Mississippi State, MS (United States)

    2016-08-15

    The discovery of a new allotropic form of elemental carbon – the fullerenes – and subsequently other novel forms of elemental carbon with pyramidalized surfaces, most notably single-walled and multi-walled carbon nanotubes, introduced a novel structural motif to the polycyclic aromatic hydrocarbons (PAHs) with nonplanar surfaces. Our research program supported by BES DOE grant DE-FG02-04ER15514 has dealt with the synthesis, structural studies, and chemistry of the novel curved-surface PAHs with carbon frameworks structurally related to fullerenes. They are referred to as “buckybowls”. We prepared several new buckybowls and, even more importantly, developed the efficient, gram-scale synthetic methodologies for the preparation of small buckybowls, most notably corannulene (C20H10) and its derivatives. In addition, the employment of the corannulene-based synthons previously developed in our laboratory led to a number of highly nonplanar molecular architectures with two or more corannulene subunits with a potential for the applications as novel materials in separation sciences, nanoelectronics, photovoltaics and catalysis. In collaboration with Professor Angelici (Iowa State) we prepared and characterized several transition metal complexes of corannulene, providing the first structural characterization of η6 metal complexes of buckybowls by a single crystal X-ray diffraction. In addition to the definitive structural characterization of the complexes we demonstrated that the (η6-C6Me6)Ru2+ unit in some relatively stable complexes activate the corannulene ligand to react with proper nucleophiles suggesting that such complexex may be used in catalysis. (Section C). We have explored the efficiency of the dispersion-based interactions of curved-surface conjugated carbon networks by high-level computational models. We showed that the curvature of such networks does not reduce the van der Waals attractions as compared to the planar systems of similar size. We than

  18. Six-Membered Aromatic Polyazides: Synthesis and Application

    OpenAIRE

    Sergei V. Chapyshev

    2015-01-01

    Aromatic polyazides are widely used as starting materials in organic synthesis and photochemical studies, as well as photoresists in microelectronics and as cross-linking agents in polymer chemistry. Some aromatic polyazides possess high antitumor activity, while many others are of considerable interest as high-energy materials and precursors of high-spin nitrenes and C3N4 carbon nitride nanomaterials. The use of aromatic polyazides in click-reactions may be a new promising direction in the d...

  19. Mechanisms for polycyclic aromatic hydrocarbon degradation by ligninolytic fungi.

    OpenAIRE

    Hammel, K E

    1995-01-01

    Ligninolytic fungi accomplish the partial degradation of numerous aromatic organopollutants. Their ability to degrade polycyclic aromatic hydrocarbons (PAHs) is particularly interesting because eukaryotes were previously considered to be unable to cleave fused-ring aromatics. Recent results indicate that extracellular peroxidases of these fungi are responsible for the initial oxidation of PAHs. Fungal lignin peroxidases oxidize certain PAHs directly, whereas fungal manganese peroxidases co-ox...

  20. Aromatic plant production on metal contaminated soils

    International Nuclear Information System (INIS)

    Zheljazkov, Valtcho D.; Craker, Lyle E.; Xing Baoshan; Nielsen, Niels E.; Wilcox, Andrew

    2008-01-01

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha -1 for Cd, 660 g ha -1 for Pb, 180 g ha -1 for Cu, 350 g ha -1 for Mn, and 205 g ha -1 for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 μm) particles, although there were larger particles (1-5 μm) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil

  1. Aromatic plant production on metal contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Zheljazkov, Valtcho D. [Mississippi State, Department of Plant and Soil Sciences and North Mississippi Research and Extension Center, 5421 Highway 145 South, Verona, MS 38879 (United States)], E-mail: vj40@pss.msstate.edu; Craker, Lyle E.; Xing Baoshan [Department of Plant and Soil Sciences, 12 Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States); Nielsen, Niels E. [Plant Nutrition and Soil Fertility Lab, Department of Agricultural Sciences, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK1871, Copenhagen (Denmark); Wilcox, Andrew [Harper Adams University College, Newport, Shropshire, TF10 8NB (United Kingdom)

    2008-06-01

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha{sup -1} for Cd, 660 g ha{sup -1} for Pb, 180 g ha{sup -1} for Cu, 350 g ha{sup -1} for Mn, and 205 g ha{sup -1} for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 {mu}m) particles, although there were larger particles (1-5 {mu}m) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil.

  2. Aromatic plant production on metal contaminated soils.

    Science.gov (United States)

    Zheljazkov, Valtcho D; Craker, Lyle E; Xing, Baoshan; Nielsen, Niels E; Wilcox, Andrew

    2008-06-01

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha(-1) for Cd, 660 g ha(-1) for Pb, 180 g ha(-1) for Cu, 350 g ha(-1) for Mn, and 205 g ha(-1) for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil.

  3. Petroleum and individual polycyclic aromatic hydrocarbons

    Science.gov (United States)

    Albers, Peter H.; Hoffman, David J.; Rattner, Barnett A.; Burton, G. Allen; Cairns, John

    1995-01-01

    Crude petroleum, refined-petroleum products, and individual polycyclic aromatic hydrocarbons (PAHs) contained within petroleum are found throughout the world. their presence has been detected in living and nonliving components of ecosystems. Petroleum can be an environmental hazard for wild animals and plants. Individual PAHs are also hazardous to wildlife, but they are most commonly associated with human illnesses. Because petroleum is a major environmental source of these PAHs, petroleum and PAHs are jointly presented in this chapter. Composition, sources, environmental fate, and toxic effects on all living components of aquatic and terrestrial environments are addessed.

  4. Polycyclic aromatic hydrocarbons profile of kitchen dusts.

    Science.gov (United States)

    Iwegbue, Chukwujindu M A

    2011-03-01

    Concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) were determined in thirty dust samples collected from kitchens that use wood cook system (WCS), kerosene stove cook system (KSCS) and butane gas cook system (BGCS). The total PAHs concentrations ranged from 52 to 497, 39 to 96 and 37 to 155 μg kg(-1) for WCS, KSCS and BGCS respectively. The results indicate predominance of lower molecular weight (2-3 rings) over higher molecular weight PAHs and users of wood cook system are more exposed to higher levels of PAHs than the users of either kerosene cook system or butane gas cook system.

  5. Microbial degradation of polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Volkering, F.; Breure, A.M.; Andel, J.G. van

    1992-01-01

    Polycyclic aromatic hydrocarbons (PAH) are hazardous compounds originating from oil, tar, creosote, or from incomplete combustion of fossil fuels. Application of biotechnological techniques for remediation of polluted soils from PAH demonstrated that the high molecular compounds are degraded very slowly, and that the residual concentration of PAH often is too high to permit application of the treated soil. Investigations were started to establish process parameters for optimal biodegradation of PAH. The aim is to achieve a relation between the physical properties of PAH and the biodegradation kinetics in different matrices, in order to identify applicability of biotechnological cleanup methods for waste streams and polluted soil. (orig.) [de

  6. Aromatic metabolism of filamentous fungi in relation to the presence of aromatic compounds in plant biomass

    NARCIS (Netherlands)

    Mäkelä, Miia R; Marinović, Mila; Nousiainen, Paula; Liwanag, April J M; Benoit, Isabelle; Sipilä, Jussi; Hatakka, Annele; de Vries, Ronald P; Hildén, Kristiina S

    2015-01-01

    The biological conversion of plant lignocellulose plays an essential role not only in carbon cycling in terrestrial ecosystems but also is an important part of the production of second generation biofuels and biochemicals. The presence of the recalcitrant aromatic polymer lignin is one of the major

  7. Dynamical attraction to stable processes

    OpenAIRE

    Fisher, Albert M.; Talet, Marina

    2012-01-01

    We apply dynamical ideas within probability theory, proving an almost-sure invariance principle in log density for stable processes. The familiar scaling property (self-similarity) of the stable process has a stronger expression, that the scaling flow on Skorokhod path space is a Bernoulli flow. We prove that typical paths of a random walk with i.i.d. increments in the domain of attraction of a stable law can be paired with paths of a stable process so that, after applying a non-random regula...

  8. Combinations of Aromatic and Aliphatic Radiolysis.

    Science.gov (United States)

    LaVerne, Jay A; Dowling-Medley, Jennifer

    2015-10-08

    The production of H(2) in the radiolysis of benzene, methylbenzene (toluene), ethylbenzene, butylbenzene, and hexylbenzene with γ-rays, 2-10 MeV protons, 5-20 MeV helium ions, and 10-30 MeV carbon ions is used as a probe of the overall radiation sensitivity and to determine the relative contributions of aromatic and aliphatic entities in mixed hydrocarbons. The addition of an aliphatic side chain with progressively from one to six carbon lengths to benzene increases the H(2) yield with γ-rays, but the yield seems to reach a plateau far below that found from a simple aliphatic such as cyclohexane. There is a large increase in H(2) with LET (linear energy transfer) for all of the substituted benzenes, which indicates that the main process for H(2) formation is a second-order process and dominated by the aromatic entity. The addition of a small amount of benzene to cyclohexane can lower the H(2) yield from the value expected from a simple mixture law. A 50:50% volume mixture of benzene-cyclohexane has essentially the same H(2) yield as cyclohexylbenzene at a wide variation in LET, suggesting that intermolecular energy transfer is as efficient as intramolecular energy transfer.

  9. Zirconacyclopentadiene-annulated polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Kiel, Gavin R.; Ziegler, Micah S.; Tilley, T. Don [Department of Chemistry, University of California, Berkeley, CA (United States)

    2017-04-18

    Syntheses of large polycyclic aromatic hydrocarbons (PAHs) and graphene nanostructures demand methods that are capable of selectively and efficiently fusing large numbers of aromatic rings, yet such methods remain scarce. Herein, we report a new approach that is based on the quantitative intramolecular reductive cyclization of an oligo(diyne) with a low-valent zirconocene reagent, which gives a PAH with one or more annulated zirconacyclopentadienes (ZrPAHs). The efficiency of this process is demonstrated by a high-yielding fivefold intramolecular coupling to form a helical ZrPAH with 16 fused rings (from a precursor with no fused rings). Several other PAH topologies are also reported. Protodemetalation of the ZrPAHs allowed full characterization (including by X-ray crystallography) of PAHs containing one or more appended dienes with the ortho-quinodimethane (o-QDM) structure, which are usually too reactive for isolation and are potentially valuable for the fusion of additional rings by Diels-Alder reactions. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Tricyclic Antidepressants and Tetracyclic Antidepressants

    Science.gov (United States)

    ... 2016. Amoxapine (prescribing information). Verna, Salcette Goa, India: Watson Pharma; 2014. http://www.accessdata.fda.gov/drugsatfda_ ... mayoclinic.org/diseases-conditions/depression/in-depth/antidepressants/ART-20046983 . Mayo Clinic Footer Legal Conditions and Terms ...

  11. magnetooptical phenomena in microcrystal suspensions of deuterated aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Spartakov, A.A.; Tolstoi, N.A. [St. Petersburg State Univ., Peterhof (Russian Federation)

    1995-11-01

    Magnetooptical studies of microcrystal suspensions of aromatic molecules containing polycondensed benzene rings with deuterium atoms substituted for hydrogen atoms showed that the new type of magnetism (aromagnetism) that was found in microcrystals of usual (undeuterated) aromatic compounds cannot be explained by the magnetic ordering of nuclear spins in these microcrystals. 4 refs., 1 fig.

  12. High atmosphere–ocean exchange of semivolatile aromatic hydrocarbons

    KAUST Repository

    González-Gaya, Belén

    2016-05-16

    Polycyclic aromatic hydrocarbons, and other semivolatile aromatic-like compounds, are an important and ubiquitous fraction of organic matter in the environment. The occurrence of semivolatile aromatic hydrocarbons is due to anthropogenic sources such as incomplete combustion of fossil fuels or oil spills, and other biogenic sources. However, their global transport, fate and relevance for the carbon cycle have been poorly assessed, especially in terms of fluxes. Here we report a global assessment of the occurrence and atmosphere-ocean fluxes of 64 polycyclic aromatic hydrocarbons analysed in paired atmospheric and seawater samples from the tropical and subtropical Atlantic, Pacific and Indian oceans. The global atmospheric input of polycyclic aromatic hydrocarbons to the global ocean is estimated at 0.09 Tg per month, four times greater than the input from the Deepwater Horizon spill. Moreover, the environmental concentrations of total semivolatile aromatic-like compounds were 10 2 -10 3 times higher than those of the targeted polycyclic aromatic hydrocarbons, with a relevant contribution of an aromatic unresolved complex mixture. These concentrations drive a large global deposition of carbon, estimated at 400 Tg C yr -1, around 15% of the oceanic CO2 uptake. © 2016 Macmillan Publishers Limited.

  13. Metal Triflates for the Production of Aromatics from Lignin

    NARCIS (Netherlands)

    Deuss, Peter J.; Lahive, Ciaran W.; Lancefield, Christopher S.; Westwood, Nicholas J.; Kamer, Paul C. J.; Barta, Katalin; de Vries, Johannes G.

    2016-01-01

    The depolymerization of lignin into valuable aromatic chemicals is one of the key goals towards establishing economically viable biorefineries. In this contribution we present a simple approach for converting lignin to aromatic monomers in high yields under mild reaction conditions. The methodology

  14. A Review of Polycyclic Aromatic Hydrocarbons and Heavy Metal ...

    African Journals Online (AJOL)

    A Review of Polycyclic Aromatic Hydrocarbons and Heavy Metal Contamination of Fish from Fish Farms. ... Journal of Applied Sciences and Environmental Management ... Polycyclic aromatic hydrocarbons (PAHs) and heavy metals contribute to pollutants in aquaculture facilities and thus need to be further investigated.

  15. Polycyclic Aromatic Hydrocarbons in Air and their Toxic Potency

    Indian Academy of Sciences (India)

    Among the urban air pollutants, polycyclic aromatic hydrocar- bons (P AHs) are a large group of over 100 different chemical compounds with 2 to 7 aromatic rings. Large quantities of such compounds are released into environment by various human activities. Recently PAHs in the environment have become.

  16. A feasibility study on identification of Basmati (aromatic) rice using ...

    Indian Academy of Sciences (India)

    The shift in transplantation in temporal domain and difference in canopy volume formed the basis of characterization of rice crop into two different varieties namely aromatic and non-aromatic. Multitemporal HH polarization data along with rate of change of cross polarization ratio (HH/HV) from July to September 2011 was ...

  17. Laboratory Investigation of Organic Aerosol Formation from Aromatic Hydrocarbons

    Science.gov (United States)

    Molina, Luisa T.; Molina, Mario J.; Zhang, Renyi

    2006-08-23

    Our work for this DOE funded project includes: (1) measurements of the kinetics and mechanism of the gas-phase oxidation reactions of the aromatic hydrocarbons initiated by OH; (2) measurements of aerosol formation from the aromatic hydrocarbons; and (3) theoretical studies to elucidate the OH-toluene reaction mechanism using quantum-chemical and rate theories.

  18. Continuous group and electron-count rules in aromaticity

    Indian Academy of Sciences (India)

    Pradeep Kumar

    2018-02-07

    Feb 7, 2018 ... ues of aromatic indexes, like rig current and resonance energy do differ for benzene and toluene. As soon as aromaticity in inorganic compounds had started to sur- face, a search for similar electron count rules like Hückel rule also started. For example, when fullerene was dis- covered and found to have ...

  19. C-Nucleosides Derived from Simple Aromatic Hydrocarbons

    OpenAIRE

    Chaudhuri, Narayan C.; Ren, Rex X.-F.; Kool, Eric T.

    1997-01-01

    We describe the synthesis, structure and DNA incorporation of a class of novel aromatic C-deoxynucleosides in which benzenes and larger polycyclic aromatics serve as DNA base analogs. Novel approaches have been developed for glycosidic bond formation and for epimenzation of the anomeric substitutents to β-configuration, and we describe some of the properties of such compounds in DNA.

  20. Delayed fluorescence from upper excited singlet states of aromatic ketones

    International Nuclear Information System (INIS)

    Nickel, B.; Roden, G.

    1980-01-01

    With liquid solutions of the aromatic ketones anthraquinone and xanthone, a P-type delayed fluorescence from upper excited singlet states, resulting from triplet-triplet annihilation, has been observed. Some peculiarities of the triplet-triplet annihilation of aromatic ketones are discussed. (orig.)

  1. Application of aromatization catalyst in synthesis of carbon nanotubes

    Indian Academy of Sciences (India)

    In a typical chemical vapour deposition (CVD) process for synthesizing carbon nanotubes (CNTs), it was found that the aromatization catalysts could promote effectively the formation of CNT. The essence of this phenomenon was attributed to the fact that the aromatization catalyst can accelerate the ...

  2. Proximate Composition, Mineral Content and Fatty Acids Analyses of Aromatic and Non-Aromatic Indian Rice

    Directory of Open Access Journals (Sweden)

    Deepak Kumar Verma

    2017-01-01

    Full Text Available Awareness on nutritive value and health benefits of rice is of vital importance in order to increase the consumption of rice in daily diet of the human beings. In this study, a total of six aromatic and two non-aromatic rice accessions grown in India were analysed for their nutritional quality attributes including proximate composition, mineral contents and fatty acids. Data with three replications were used to measure Pearson's simple correlation co-efficient in order to establish the relationship among various nutritional quality attributes. The result on proximate composition showed that Govind Bhog had the highest moisture (13.57% and fat (0.92% content, which signifies its tasty attribute. Badshah Bhog exhibited the highest fibre content (0.85%, carbohydrate content (82.70% and food energy (365.23 kCal per 100 g. Among the minerals, the higher Ca (98.75 mg/kg, Zn (17.00 mg/kg and Fe (31.50 mg/kg were in Gopal Bhog, whereas the highest Na (68.85 mg/kg was in Badshah Bhog, the highest K (500.00 mg/kg was in Swetganga, Khushboo and Sarbati. The highest contents of unsaturated fatty acids viz. oleic acid (49.14%, linoleic acid (46.99% and linolenic acid (1.27% were found in Sarbati, whereas the highest content of saturated fatty acids viz. myristic acid (4.60% and palmitic acid (31.91% were found in Govind Bhog and stearic acid (6.47% in Todal. The identified aromatic rice accessions Gopal Bhog, Govind Bhog and Badshah Bhog and non-aromatic rice accession Sarbati were found nutritionally superior among all eight tested accessions. The nutritional quality oriented attributes in this study were competent with recognized prominent aromatic and non-aromatic rice accessions as an index of their nutritional worth and recommend to farmers and consumers which may be graded as export quality rice with good unique nutritional values in international market.

  3. 4N electron aromatic cycles in polycyclic hydrocarbons.

    Science.gov (United States)

    Mauksch, Michael; Tsogoeva, Svetlana B

    2017-05-31

    Polycyclic fully conjugated hydrocarbons in which aromatics are fused to aromatics - or aromatics to antiaromatics - are important as potential organic semiconductors. Herein we explore the only remaining fusion pattern of antiaromatics to antiaromatics. It is shown computationally that the central antiaromatic unit (cyclobutadiene or pentalene) in such a three-unit polycyclic hydrocarbon, generated by fusion of three antiaromatic molecules, turns aromatic according to magnetic shielding (NICS) criteria. The resulting neutral 4N electron molecules possess a 4N π electron perimeter with pronounced CC bond length equalization (as indicated by the HOMA geometric index) and significant aromatic stabilization energies (computed using the isomerization-stabilization method) and could be promising synthetic targets with small HOMO-LUMO gaps.

  4. Stable π-Extended p -Quinodimethanes: Synthesis and Tunable Ground States

    KAUST Repository

    Zeng, Zebing

    2014-12-18

    © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. p-Quinodimethane (p-QDM) is a highly reactive hydrocarbon showing large biradical character in the ground state. It has been demonstrated that incorporation of the p-QDM moiety into an aromatic hydrocarbon framework could lead to new π-conjugated systems with significant biradical character and unique optical, electronic and magnetic properties. On the other hand, the extension of p-QDM is expected to result in molecules with even larger biradical character and higher reactivity. Therefore, the synthesis of stable π-extended p-QDMs is very challenging. In this Personal Account we will briefly discuss different stabilizing strategies and synthetic methods towards stable π-extended p-QDMs with tunable ground states and physical properties, including two types of polycyclic hydrocarbons: (1) tetrabenzo-Tschitschibabin\\'s hydrocarbons, and (2) tetracyano-rylenequinodimethanes. We will discuss how the aromaticity, substituents and steric hindrance play important roles in determining their ground states and properties. Incorporation of the p-quinodimethane moiety into aromatic hydrocarbon frameworks can lead to new π-conjugated systems with significant biradical character and unique optical, electronic and magnetic properties. Furthermore, the extension of p-QDM is expected to result in molecules with even larger biradical character and higher reactivity. In this Personal Account, different stabilizing strategies and synthetic methods towards stable π-extended p-QDMs with tunable ground states and physical properties are briefly discussed, including the roles of aromaticity, substituents and steric hindrance.

  5. Polycyclic Aromatic Hydrocarbon Emission Toward the Galactic Bulge

    Science.gov (United States)

    Shannon, M. J.; Peeters, E.; Cami, J.; Blommaert, J. A. D. L.

    2018-03-01

    We examine polycyclic aromatic hydrocarbon (PAH), dust, and atomic/molecular emission toward the Galactic bulge using Spitzer Space Telescope observations of four fields: C32, C35, OGLE, and NGC 6522. These fields are approximately centered on (l, b) = (0.°0, 1.°0), (0.°0, ‑1.°0), (0.°4, ‑2.°4), and (1.°0, ‑3.°8), respectively. Far-infrared photometric observations complement the Spitzer/IRS spectroscopic data and are used to construct spectral energy distributions. We find that the dust and PAH emission are exceptionally similar between C32 and C35 overall, in part explained due to their locations—they reside on or near boundaries of a 7 Myr old Galactic outflow event and are partly shock-heated. Within the C32 and C35 fields, we identify a region of elevated Hα emission that is coincident with elevated fine-structure and [O IV] line emission and weak PAH feature strengths. We are likely tracing a transition zone of the outflow into the nascent environment. PAH abundances in these fields are slightly depressed relative to typical ISM values. In the OGLE and NGC 6522 fields, we observe weak features on a continuum dominated by zodiacal dust. SED fitting indicates that thermal dust grains in C32 and C35 have temperatures comparable to those of diffuse, high-latitude cirrus clouds. Little variability is detected in the PAH properties between C32 and C35, indicating that a stable population of PAHs dominates the overall spectral appearance. In fact, their PAH features are exceptionally similar to that of the M82 superwind, emphasizing that we are probing a local Galactic wind environment.

  6. Polycyclic aromatic hydrocarbons (PAHs) in yogurt samples.

    Science.gov (United States)

    Battisti, Chiara; Girelli, Anna Maria; Tarola, Anna Maria

    2015-01-01

    The concentrations and distributions of major polycyclic aromatic hydrocarbons (PAHs) were determined in 20 kinds of yogurt specimens collected from Italian supermarkets using reversed phase high-performance liquid chromatography equipped with fluorescence detection. The method was validated by determination of recovery percentages, precision (repeatability) and sensitivity (limits of detection) with yogurt samples fortified at 0.25, 0.5 and 1 µg/kg concentration levels. The recovery of 13 PAHs, with the exception of naphthalene and acenaphthene, ranged from 61% to 130% and from 60% to 97% at all the levels for yogurts with low (0.1%) and high (3.9%) fat content, respectively. The method is repeatable with relative standard deviation values yogurts with low and high fats were compared.

  7. Interstellar Polycyclic Aromatic Compounds and Astrophysics

    Science.gov (United States)

    Hudgins, Douglas M.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role polycyclic aromatic compounds (PAC) in the interstellar medium (ISM). Twenty years ago, the notion of an abundant population of large, carbon rich molecules in the ISM was considered preposterous. Today, the unmistakable spectroscopic signatures of PAC - shockingly large molecules by previous interstellar chemistry standards - are recognized throughout the Universe. In this paper, we will examine the interstellar PAC model and its importance to astrophysics, including: (1) the evidence which led to inception of the model; (2) the ensuing laboratory and theoretical studies of the fundamental spectroscopic properties of PAC by which the model has been refined and extended; and (3) a few examples of how the model is being exploited to derive insight into the nature of the interstellar PAC population.

  8. Photochemically induced oscillations of aromatic pentazadienes

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, T.; Hahn, C.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Aromatic pentazadienes are used to enhance the laser induced ablation of standard polymers with low absorption in the UV. Therefore the photochemistry of substituted 1,5-diaryl-3-alkyl-1,4-pentazadiene monomers was studied with a pulsed excimer laser as irradiation source. The net photochemical reaction proceeds in an overall one-step pathway A{yields}B. Quantum yields for the laser decomposition were determined to be up to 10%. An oscillating behaviour of the absorption was found during the dark period following the irradiation. The temperature dependence of this dark reaction has been studied. An attempt to model this behaviour in terms of a non-linear coupling between heat released, heat transfer, and reaction kinetics will be described. (author) 4 figs., 4 refs.

  9. Naturally occurring antifungal aromatic esters and amides

    International Nuclear Information System (INIS)

    Ali, M.S.; Shahnaz; Tabassum, S.; Ogunwande, I.A.; Pervez, M.K.

    2010-01-01

    During the search of antifungal natural products from terrestrial plants, a new long chained aromatic ester named grandiflorate along with spatazoate from Portulaca grandiflora and N-[2-methoxy-2-(4-methoxyphenyl) ethyl]-trans-cinnamide and aegeline from Solanum erianthum of Nigeria were isolated and tested against six fungal species. The known constituents have not been reported so far from mentioned investigated plants. Structures of the isolated compounds were elucidated with the aid of spectroscopic techniques including two dimensional NMR experiments. Among the compounds, the esters found more potent than amides against Candida albicans and Aspergillus flavus. The new compound grandiflorate gave response against all tested fungal species while aegeline was found to give lowest inhibition during this study. (author)

  10. Environmental Remediation: Removal of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Nkansah, Marian Asantewah

    2012-11-15

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous persistent semi-volatile organic compounds. They are contaminants that are resistant to degradation and can remain in the environment for long periods due to their high degree of conjugation, and aromaticity. PAHs are present in industrial effluents as products of incomplete combustion processes of organic compounds. Petroleum, coal and shale oil contain extremely complex mixtures of these PAHs, and their transport and refining process can also result in the release of PAHs. It is therefore prudent that such effluents are treated before discharge into the environment. In this project, different approaches to the treatment of PAHs have been investigated. Hydrous pyrolysis has been explored as a potential technique for degrading PAHs in water using anthracene as a model compound. The experiments were performed under different conditions of temperature, substrate, redox systems and durations. The conditions include oxidising systems comprising pure water, hydrogen peroxide and Nafion-SiO2 solid catalyst in water; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts to assess a range of reactivities. Products observed in GCMS analysis of the extract from the water phase include anthrone, anthraquinone, xanthone and multiple hydro-anthracene derivatives (Paper I). In addition a modified version of the Nafion-SiO2 solid catalyst in water oxidising system was tested; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts were adopted for the conversion of a mixture of anthracene, fluorene and fluoranthene. The rate of conversion in the mixture was high as compared to that of only anthracene (Paper II). Also the use of LECA (Lightweight expanded clay aggregates) as an adsorbent (Paper III) for PAHs (phenanthrene, fluoranthene and pyrene) removal from water has been.(Author)

  11. [Aromatic trees and herbs that connect Heaven and earth].

    Science.gov (United States)

    Sugiyama, Shigeru

    2007-01-01

    It has been known for a long time that aromatic substances (essential oils) contained in plants often exert psychological effects ranging from sedative to excitatory actions. Medicinal effects have also been confirmed through numerous experiences. In ancient times, aromatic trees and herbs were offered to deities, mostly as incenses that were believed to carry people's wishes, such as requests to cure sick people, to Heaven. In the medieval periods, their deep and subtle aromas elevated aromatics to so-called "treasures of the world," while their various medicinal activities including the psychological effects made them useful as treatment measures. Demands for aromatics in our time as raw materials for cosmetics far outweigh those as medicines. The market for aromatics, however, has become virtually non-existent, as the popularity of synthetic aromatics for cosmetics grew. In West Asia, olibanum and myrrh were highly regarded both as incense and analgesics for tooth pain. In India, sandalwood was prized as incense, and sometimes as an antidote for poisonous snakebites. In China and Japan, agalloch (Kyara is agalloch of the highest quality) was considered the most significant of the aromatics. Agalloch and many other aromatics were in possession of the Emperor's family in 8th century Japan; some of which are kept in Nara to this day. Olfactory sense is ultimately identified in the olfactory area of the frontal lobe of the human brain. When stimuli reach the olfactory area, they also affect other cells such as those around the hypothalamus when they go through it. The hypothalamus is the center of instinctive behaviors with the centers for appetite, sexuality, blood pressure and thirst, and greatly affects the psychological side of the human behavior with its delicate connection to the autonomic nerve system. It therefore may not be surprising that aromatics were often used in medicine, which once had close ties with shamanism, animism and other religious activities

  12. Exploring aromatic chemical space with NEAT: novel and electronically equivalent aromatic template.

    Science.gov (United States)

    Tu, Meihua; Rai, Brajesh K; Mathiowetz, Alan M; Didiuk, Mary; Pfefferkorn, Jeffrey A; Guzman-Perez, Angel; Benbow, John; Guimarães, Cristiano R W; Mente, Scot; Hayward, Matthew M; Liras, Spiros

    2012-05-25

    In this paper, we describe a lead transformation tool, NEAT (Novel and Electronically equivalent Aromatic Template), which can help identify novel aromatic rings that are estimated to have similar electrostatic potentials, dipoles, and hydrogen bonding capabilities to a query template; hence, they may offer similar bioactivity profiles. In this work, we built a comprehensive heteroaryl database, and precalculated high-level quantum mechanical (QM) properties, including electrostatic potential charges, hydrogen bonding ability, dipole moments, chemical reactivity, and othe properties. NEAT bioisosteric similarities are based on the electrostatic potential surface calculated by Brood, using the precalculated QM ESP charges and other QM properties. Compared with existing commercial lead transformation software, (1) NEAT is the only one that covers the comprehensive heteroaryl chemical space, and (2) NEAT offers a better characterization of novel aryl cores by using high-evel QM properties that are relevant to molecular interactions. NEAT provides unique value to medicinal chemists quickly exploring the largely uncharted aromatic chemical space, and one successful example of its application is discussed herein.

  13. Fused electron deficient semiconducting polymers for air stable electron transport

    KAUST Repository

    Onwubiko, Ada

    2018-01-23

    Conventional semiconducting polymer synthesis typically involves transition metal-mediated coupling reactions that link aromatic units with single bonds along the backbone. Rotation around these bonds contributes to conformational and energetic disorder and therefore potentially limits charge delocalisation, whereas the use of transition metals presents difficulties for sustainability and application in biological environments. Here we show that a simple aldol condensation reaction can prepare polymers where double bonds lock-in a rigid backbone conformation, thus eliminating free rotation along the conjugated backbone. This polymerisation route requires neither organometallic monomers nor transition metal catalysts and offers a reliable design strategy to facilitate delocalisation of frontier molecular orbitals, elimination of energetic disorder arising from rotational torsion and allowing closer interchain electronic coupling. These characteristics are desirable for high charge carrier mobilities. Our polymers with a high electron affinity display long wavelength NIR absorption with air stable electron transport in solution processed organic thin film transistors.

  14. The future role of aromatics in refining and petrochemistry. Proceedings of the DGMK-Conference (Authors' manuscripts)

    Energy Technology Data Exchange (ETDEWEB)

    Emig, G.; Rupp, M.; Weitkamp, J. [eds.

    1999-07-01

    Topic of this conference has been the furure role of aromatics in the refinign industry. The articles deal with the following topics: Refining; legal aspects in the aromatics market; transportation fuels; dearomatization; catalytic reforming and aromatics; separation processes for aromatics; oxidation and ammoxidation of aromatics; electrophilic substitution of aromatics; hydrogenation of benzene; zeolites. (orig./sr)

  15. Shelf-Stable Food Safety

    Science.gov (United States)

    ... is an MRE? Is an MRE shelf stable? What foods are packaged in retort packages? What is aseptic ... type of package is used for aseptic processing? What foods are packaged in aseptic packages? Can I microwave ...

  16. Pharmaceuticals labelled with stable isotopes

    International Nuclear Information System (INIS)

    Krumbiegel, P.

    1986-11-01

    The relatively new field of pharmaceuticals labelled with stable isotopes is reviewed. Scientific, juridical, and ethical questions are discussed concerning the application of these pharmaceuticals in human medicine. 13 C, 15 N, and 2 H are the stable isotopes mainly utilized in metabolic function tests. Methodical contributions are given to the application of 2 H, 13 C, and 15 N pharmaceuticals showing new aspects and different states of development in the field under discussion. (author)

  17. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1984-03-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

  18. How non-conventional feedstocks will affect aromatics technologies

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, E. [Clariant Produkte (Deutschland) GmbH, Muenchen (Germany)

    2013-11-01

    The abundance of non-conventional feedstocks such as coal and shale gas has begun to affect the availability of traditional base chemicals such as propylene and BTX aromatics. Although this trend is primarily fueled by the fast growing shale gas economy in the US and the abundance of coal in China, it will cause the global supply and demand situation to equilibrate across the regions. Lower demand for gasoline and consequently less aromatics rich reformate from refineries will further tighten the aromatics markets that are expected to grow at healthy rates, however. Refiners can benefit from this trend by abandoning their traditional fuel-oriented business model and becoming producers of petrochemical intermediates, with special focus on paraxylene (PX). Cheap gas from coal (via gasification) or shale reserves is an advantaged feedstock that offers a great platform to make aromatics in a cost-competitive manner, especially in regions where naphtha is in short supply. Gas condensates (LPG and naphtha) are good feedstocks for paraffin aromatization, and methanol from coal or (shale) gas can be directly converted to BTX aromatics (MTA) or alkylated with benzene or toluene to make paraxylene. Most of today's technologies for the production and upgrading of BTX aromatics and their derivatives make use of the unique properties of zeolites. (orig.)

  19. Long-term performance and stability of a continuous granular airlift reactor treating a high-strength wastewater containing a mixture of aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Carlos; Suárez-Ojeda, María Eugenia; Carrera, Julián, E-mail: julian.carrera@uab.cat

    2016-02-13

    Highlights: • Aerobic biodegradation of a mixture of aromatics is feasible in a granular reactor. • Applied organic loading rate is a key parameter for an optimal reactor performance. • Stable mature aerobic granules were maintained 400 days in a continuous reactor. • Sphingobium, Cytophaga and Comamonas were the main genera in the aerobic granules. - Abstract: Continuous feeding operation of an airlift reactor and its inoculation with mature aerobic granules allowed the successful treatment of a mixture of aromatic compounds (p-nitrophenol, o-cresol and phenol). Complete biodegradation of p-nitrophenol, o-cresol, phenol and their metabolic intermediates was achieved at an organic loading rate of 0.61 g COD L{sup −1} d{sup −1}. Stable granulation was obtained throughout the long-term operation (400 days) achieving an average granule size of 2.0 ± 1 mm and a sludge volumetric index of 26 ± 1 mL g{sup −1} TSS. The identified genera in the aerobic granular biomass were heterotrophic bacteria able to consume aromatic compounds. Therefore, the continuous feeding regimen and the exposure of aerobic granules to a mixture of aromatic compounds make possible to obtain good granulation and high removal efficiency.

  20. Determination and content of polycyclic aromatic hydrocarbons in bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, H.J.; Kaschani, D.T.

    1977-12-01

    The institut for Petrolium Research in Hanover has been engaged for some ten years on the analysis of bitumens. What is now known on the subject from the works of various authors is reviewed here. One of the points dealt with in the report is that, owing to its content of polycyclic aromatic hydrocarbons, bitumen is not a potential carcinogen. The analysis of the polycyclic aromatic hydrocarbons and their results, aromatic hydrocarbons in bitumen vapours and their solubility in water from bitumens are dealt with.

  1. Aromatization of 16alpha-hydroxyandrostenedione by human placental microsomes: effect of preincubation with suicide substrates of androstenedione aromatization.

    Science.gov (United States)

    Numazawa, Mitsuteru; Tachibana, Mii; Mutsumi, Ayako; Yoshimura, Akiko; Osawa, Yoshio

    2002-06-01

    Estrogen synthase (aromatase) catalyzes the aromatization of androstenedione (AD) as well as 16alpha-hydroxyandrostenedione (16alpha-OHAD) leading to estrone and estriol, respectively. We found that several steroid analogs including 4-hydroxyandrostenedione (1), 6-oxoandrostenedione (6-oxoAD, 2) and its 19-hydroxy analog (3), 10beta-acetoxyestr-5-ene-7,17-dione (4), androst-5-ene-4,7,17-trione (5), and 17alpha-ethynyl-19-norteststerone (6), which are known suicide inactivators of AD aromatization, are not effective in inactivating 16alpha-OHAD aromatization in a time-dependent manner. The compounds were tested with the use of human placental microsomes and 1beta-tritiated-16alpha-OHAD as the substrate. The results of the tritium water method of 16alpha-OHAD aromatization was confirmed by the gas chromatography-mass spectrometry (GC-MS) method of estriol formation. The 1beta-tritiated-AD was used to measure AD aromatization as a positive control for these experiments. The compounds were tested at concentrations up to 40-fold higher than the K(i)'s determined for inhibition of AD aromatization. These studies suggest that differences exist in the binding site structures responsible for aromatization of 16alpha-OHAD and AD.

  2. Stable Boundary Layer Education (STABLE) Final Campaign Summary

    Energy Technology Data Exchange (ETDEWEB)

    Turner, David D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-01

    The properties of, and the processes that occur in, the nocturnal stable boundary layer are not well understood, making it difficult to represent adequately in numerical models. The nocturnal boundary layer often is characterized by a temperature inversion and, in the Southern Great Plains region, a low-level jet. To advance our understanding of the nocturnal stable boundary layer, high temporal and vertical resolution data on the temperature and wind properties are needed, along with both large-eddy simulation and cloud-resolving modeling.

  3. Carenium—Calkyl Bond Making and Breaking: Key Process in the Platinum-Mediated Caryl—Calkyl Bond Formation. Analogies to Organic Electrophilic Aromatic Substitution

    NARCIS (Netherlands)

    Koten, G. van; Albrecht, M.A.; Spek, A.L.

    2001-01-01

    The reaction of cationic platinum aqua complexes 2 [Pt(C6H2{CH2NMe2}2-E-4)(OH2)](X') (X' = SO3CF3, BF4) with alkyl halides RX gave various air-stable arenium complexes 3-5 containing a new C-C bond (R = Me, 3; Et, 4; Bn, 5). Electron-releasing oxo-substituents on the aromatic ligand (E = e.g., OH,

  4. Six-Membered Aromatic Polyazides: Synthesis and Application

    Directory of Open Access Journals (Sweden)

    Sergei V. Chapyshev

    2015-10-01

    Full Text Available Aromatic polyazides are widely used as starting materials in organic synthesis and photochemical studies, as well as photoresists in microelectronics and as cross-linking agents in polymer chemistry. Some aromatic polyazides possess high antitumor activity, while many others are of considerable interest as high-energy materials and precursors of high-spin nitrenes and C3N4 carbon nitride nanomaterials. The use of aromatic polyazides in click-reactions may be a new promising direction in the design of various supramolecular systems possessing interesting chemical, physical and biological properties. This review is devoted to the synthesis, properties and applications of six-membered aromatic compounds containing three and more azido groups in the ring.

  5. Aromatic Plants as a Source of Bioactive Compounds

    Directory of Open Access Journals (Sweden)

    Panagiota Florou-Paneri

    2012-09-01

    Full Text Available Aromatic plants, also known as herbs and spices, have been used since antiquity as folk medicine and as preservatives in foods. The best known aromatic plants, such as oregano, rosemary, sage, anise, basil, etc., originate from the Mediterranean area. They contain many biologically active compounds, mainly polyphenolics, which have been found to possess antimicrobial, antioxidant, antiparasitic, antiprotozoal, antifungal, and anti-inflammatory properties. Currently, the demand for these plants and their derivatives has increased because they are natural, eco-friendly and generally recognized as safe products. Therefore, aromatic plants and their extracts have the potential to become new generation substances for human and animal nutrition and health. The purpose of this review is to provide an overview of the literature surrounding the in vivo and in vitro use of aromatic plants.

  6. Extraction of Aromatics from Heavy Naphtha Using Different Solvents

    International Nuclear Information System (INIS)

    EI-Bassuoni, A.A.; Esmael, K.K.

    2004-01-01

    Aromatic hydrocarbons are very important to the petrochemical industry. Among these are benzene, toluene and xylene (BTX), which are basic raw materials for the production of a number of important petrochemicals. There are many processes used to separate aromatic from non aromatic such as fractionation, azeotropic distillation and liquid I liquid extraction, etc. Liquid - liquid extraction is unique, efficiently used for heat sensitive, close boiling components and for separation of components not possible by other unit operations and it could be done at ambient temperature makes it more energy efficient. The choice of solvent depends on the properties and boiling range of the feedstock. Through the years, a lot of selective solvents has been proposed and selected for the physical separation of aromatics in liquid liquid extraction. Among the selection criteria are the stability,. chemical compatibility, availability, environmental hazards and price of the solvent. But the basic solvent properties that make it efficient are selectivity and capacity

  7. A method for controlling the synthesis of stable twisted two-dimensional conjugated molecules

    Science.gov (United States)

    Li, Yongjun; Jia, Zhiyu; Xiao, Shengqiang; Liu, Huibiao; Li, Yuliang

    2016-01-01

    Thermodynamic stabilization (π-electron delocalization through effective conjugation) and kinetic stabilization (blocking the most-reactive sites) are important considerations when designing stable polycyclic aromatic hydrocarbons displaying tunable optoelectronic properties. Here, we demonstrate an efficient method for preparing a series of stable two-dimensional (2D) twisted dibenzoterrylene-acenes. We investigated their electronic structures and geometries in the ground state through various experiments assisted by calculations using density functional theory. We find that the length of the acene has a clear effect on the photophysical, electrochemical, and magnetic properties. These molecules exhibit tunable ground-state structures, in which a stable open-shell quintet tetraradical can be transferred to triplet diradicals. Such compounds are promising candidates for use in nonlinear optics, field effect transistors and organic spintronics; furthermore, they may enable broader applications of 2D small organic molecules in high-performance electronic and optical devices. PMID:27181692

  8. Strong Correlation Physics in Aromatic Hydrocarbon Superconductors

    Science.gov (United States)

    Capone, Massimo; Giovannetti, Gianluca

    2012-02-01

    We show, by means of ab-initio calculations, that electron-electron correlations play an important role in doped aromatic hydrocarbon superconductors, including potassium doped picene with Tc= 18K [1], coronene and phenanthrene [2]. For the case of picene the inclusion of exchange interactions by means of hybrid functionals reproduces the correct gap for the undoped compound and predicts an antiferromagnetic state for x=3, where superconductivity has been observed [3]. The latter finding is compatible with a sizable value of the correlation strength. The differences between the different compounds are analyzed and results of Dynamical Mean-Field Theory including both correlation effects and electron-phonon interactions are presented. Finally we discuss the consequences of strong correlations in an organic superconductor in relation to the properties of Cs3C60, in which electron correlations drive an antiferromagnetic state [4] but also lead to an enhancement of superconductivity [5]. 1. R. Mitsuhashi et al. Nature 464, 76 (2010)2. X.F. Wang et al, Nat. Comm. 2, 507 (2011)3. G. Giovannetti and M. Capone, Phys. Rev. B 83, 134508 (2011)4. Y. Takabayashi et al., Science 323, 1585 (2009)5. M. Capone et al. Rev. Mod. Phys. 81, 943 (2009

  9. Polycyclic aromatic hydrocarbons in the bakery chain.

    Science.gov (United States)

    Ciecierska, M; Obiedziński, M W

    2013-11-01

    The level of polycyclic aromatic hydrocarbons occurrence and the possibility of their formation in the bakery chain, its raw materials and final products, were examined. Experimental bread baking, with different baking temperatures, was performed in the Warsaw bakery, using cyclothermic deck ovens. PAHs determination was performed by high-pressure liquid chromatography with fluorescent and diode array detectors (HPLC-FLD/DAD) and confirmed by gas chromatography coupled with mass spectrometry (GC/MS). Total content of 19 PAHs in the grain, flour and bran varied from 1.07 to 3.65 μg/kg and, in bread, from 1.59 to 13.6 μg/kg depending on the part of bread and baking temperature. Based on the dough's contamination level and the influence of the baking temperature on the bread's PAHs content, it was confirmed that PAHs are formed during baking. Considering the results of the average dietary exposure to PAHs and the MOE (Margin of Exposure) analysis, it could be concluded that analysed bread and cereal products constitute little concern for consumer health. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Neutron Scattering of Aromatic and Aliphatic Liquids.

    Science.gov (United States)

    Falkowska, Marta; Bowron, Daniel T; Manyar, Haresh G; Hardacre, Christopher; Youngs, Tristan G A

    2016-07-04

    Organic solvents, such as cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene, are widely used as both reagents and solvents in industrial processes. Despite the ubiquity of these liquids, the local structures that govern the chemical properties have not been studied extensively. Herein, we report neutron diffraction measurements on liquid cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene at 298 K to obtain a detailed description of the local structure in these compounds. The radial distribution functions of the centres of the molecules, as well as the partial distribution functions for the double bond for cyclohexene and methyl group for methylcyclohexane and toluene have been calculated. Additionally, probability density functions and angular radial distribution functions were extracted to provide a full description of the local structure within the chosen liquids. Structural motifs are discussed and compared for all liquids, referring specifically to the functional group and aromaticity present in the different liquids. ©2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  11. Porphyrins Fused with Unactivated Polycyclic Aromatic Hydrocarbons

    KAUST Repository

    Diev, Vyacheslav V.

    2012-01-06

    A systematic study of the preparation of porphyrins with extended conjugation by meso,β-fusion with polycyclic aromatic hydrocarbons (PAHs) is reported. The meso-positions of 5,15-unsubstituted porphyrins were readily functionalized with PAHs. Ring fusion using standard Scholl reaction conditions (FeCl 3, dichloromethane) occurs for perylene-substituted porphyrins to give a porphyrin β,meso annulated with perylene rings (0.7:1 ratio of syn and anti isomers). The naphthalene, pyrene, and coronene derivatives do not react under Scholl conditions but are fused using thermal cyclodehydrogenation at high temperatures, giving mixtures of syn and anti isomers of the meso,β-fused porphyrins. For pyrenyl-substituted porphyrins, a thermal method gives synthetically acceptable yields (>30%). Absorption spectra of the fused porphyrins undergo a progressive bathochromic shift in a series of naphthyl (λ max = 730 nm), coronenyl (λ max = 780 nm), pyrenyl (λ max = 815 nm), and perylenyl (λ max = 900 nm) annulated porphyrins. Despite being conjugated with unsubstituted fused PAHs, the β,meso-fused porphyrins are more soluble and processable than the parent nonfused precursors. Pyrenyl-fused porphyrins exhibit strong fluorescence in the near-infrared (NIR) spectral region, with a progressive improvement in luminescent efficiency (up to 13% with λ max = 829 nm) with increasing degree of fusion. Fused pyrenyl-porphyrins have been used as broadband absorption donor materials in photovoltaic cells, leading to devices that show comparatively high photovoltaic efficiencies. © 2011 American Chemical Society.

  12. A new strategy for aromatic ring alkylation in cylindrocyclophane biosynthesis.

    Science.gov (United States)

    Nakamura, Hitomi; Schultz, Erica E; Balskus, Emily P

    2017-08-01

    Alkylation of aromatic rings with alkyl halides is an important transformation in organic synthesis, yet an enzymatic equivalent is unknown. Here, we report that cylindrocyclophane biosynthesis in Cylindrospermum licheniforme ATCC 29412 involves chlorination of an unactivated carbon center by a novel halogenase, followed by a previously uncharacterized enzymatic dimerization reaction featuring sequential, stereospecific alkylations of resorcinol aromatic rings. Discovery of the enzymatic machinery underlying this unique biosynthetic carbon-carbon bond formation has implications for biocatalysis and metabolic engineering.

  13. Aromatic VOCs global influence in the ozone production

    Science.gov (United States)

    Cabrera-Perez, David; Pozzer, Andrea

    2016-04-01

    Aromatic hydrocarbons are a subgroup of Volatile Organic Compounds (VOCs) of special interest in the atmosphere of urban and semi-urban areas. Aromatics form a high fraction of VOCs, are highly reactive and upon oxidation they are an important source of ozone. These group of VOCs are released to the atmosphere by processes related to biomass burning and fossil fuel consumption, while they are removed from the atmosphere primarily by OH reaction and by dry deposition. In addition, a branch of aromatics (ortho-nitrophenols) produce HONO upon photolysis, which is responsible of certain amount of the OH recycling. Despite their importance in the atmosphere in anthropogenic polluted areas, the influence of aromatics in the ozone production remains largely unknown. This is of particular relevance, being ozone a pollutant with severe side effects on air quality, health and climate. In this work the atmospheric impacts at global scale of the most emitted aromatic VOCs in the gas phase (benzene, toluene, xylenes, ethylbenzene, styrene, phenol, benzaldehyde and trimethylbenzenes) are analysed and assessed. Specifically, the impact on ozone due to aromatic oxidation is estimated, as this is of great interest in large urban areas and can be helpful for developing air pollution control strategies. Further targets are the quantification of the NOx loss and the OH recycling due to aromatic oxidation. In order to investigate these processes, two simulations were performed with the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The simulations compare two cases, one with ozone concentrations when aromatics are present or the second one when they are missing. Finally, model simulated ozone is compared against a global set of observations in order to better constrain the model accuracy.

  14. Highly Conductive Aromatic Functionalized Multi-Walled Carbon Nanotube for Inkjet Printable High Performance Supercapacitor Electrodes.

    Directory of Open Access Journals (Sweden)

    Sanjeev K Ujjain

    Full Text Available We report the functionalization of multiwalled carbon nanotubes (MWCNT via the 1,3-dipolar [3+2] cycloaddition of aromatic azides, which resulted in a detangled CNT as shown by transmission electron microscopy (TEM. Carboxylic moieties (-COOH on aromatic azide result in highly stable aqueous dispersion (max. conc. ~ 10 mg/mL H2O, making the suitable for inkjet printing. Printed patterns on polyethylene terephthalate (PET flexible substrate exhibit low sheet resistivity ~65 Ω. cm, which is attributed to enhanced conductivity. Fabricated Supercapacitors (SC assembled using these printed substrates exhibit good electrochemical performance in organic as well as aqueous electrolytes. High energy and power density (57.8 Wh/kg and 0.85 kW/kg in 1M H2SO4 aqueous electrolyte demonstrate the excellent performance of the proposed supercapacitor. Capacitive retention varies from ~85-94% with columbic efficiency ~95% after 1000 charge/discharge cycles in different electrolytes, demonstrating the excellent potential of the device for futuristic power applications.

  15. Degradation of Polycyclic Aromatic Hydrocarbon Pyrene by Biosurfactant-Producing Bacteria Gordonia cholesterolivorans AMP 10

    Directory of Open Access Journals (Sweden)

    Tri Handayani Kurniati

    2016-12-01

    Full Text Available Pyrene degradation and biosurfactant activity by a new strain identified as Gordonia cholesterolivorans AMP 10 were studied. The strain grew well and produced effective biosurfactants in the presence of glucose, sucrose, and crude oil. The biosurfactants production was detected by the decreased surface tension of the medium and emulsification activity.  Analysis of microbial growth parameters showed that AMP10 grew best at 50 µg mL-1 pyrene concentration, leading to 96 % degradation of pyrene within 7 days. The result of nested PCR analysis revealed that this isolate possessed the nahAc gene which encodes dioxygenase enzyme for initial degradation of Polycyclic Aromatic Hydrocarbon (PAH. Observation of both tensio-active and emulsifying activities indicated that biosurfactants which produced by AMP 10 when grown on glucose could lower the surface tension of medium from 71.3 mN/m to 24.7 mN/m and formed a stable emulsion in used lubricant oil with an emulsification index (E24 of 74%. According to the results, it is suggested that the bacterial isolates G. cholesterolivorans AMP10 are suitable candidates for bioremediation of PAH-contaminated environments.How to CiteKurniati, T. H.,  Rusmana, I. Suryani, A. & Mubarik, N. R. (2016. Degradation of Polycyclic Aromatic Hydrocarbon Pyrene by Biosurfactant-Producing Bacteria Gordonia cholesterolivorans AMP 10. Biosaintifika: Journal of Biology & Biology Education, 8(3, 336-343. 

  16. Polycyclic aromatic hydrocarbon degradation by biosurfactant-producing Pseudomonas sp. IR1

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M. [Unidad de Biotecnologia del Petroleo, Centro de Biotecnologia, Fundacion Inst. de Estudios Avanzados (IDEA), Caracas (Venezuela); Synthesis and Biotics Div., Indian Oil Corp., Research and Development Center, Haryana (India); Leon, V.; Materano, A.D.S.; Ilzins, O.A.; Galindo-Castro, I.; Fuenmayor, S.L. [Unidad de Biotecnologia del Petroleo, Centro de Biotecnologia, Fundacion Inst. de Estudios Avanzados (IDEA), Caracas (Venezuela)

    2006-03-15

    We characterized a newly isolated bacterium, designated as IR1, with respect to its ability to degrade polycyclic aromatic hydrocarbons (PAHs) and to produce biosurfactants. Isolated IR1 was identified as Pseudomonas putida by analysis of 16S rRNA sequences (99.6% homology). It was capable of utilizing two-, three- and four-ring PAHs but not hexadecane and octadecane as a sole carbon and energy source. PCR and DNA hybridization studies showed that enzymes involved in PAH metabolism were related to the naphthalene dioxygenase pathway. Observation of both tensio-active and emulsifying activities indicated that biosurfactants were produced by IR1 during growth on both water miscible and immiscible substrates. The biosurfactants lowered the surface tension of medium from 54.9 dN cm{sup -1} to 35.4 dN cm{sup -1} and formed a stable and compact emulsion with an emulsifying activity of 74% with diesel oil, when grown on dextrose. These findings indicate that this isolate may be useful for bioremediation of sites contaminated with aromatic hydrocarbons. (orig.)

  17. Chemistry of polycyclic aromatic hydrocarbons formation from phenyl radical pyrolysis and reaction of phenyl and acetylene.

    Science.gov (United States)

    Comandini, A; Malewicki, T; Brezinsky, K

    2012-03-15

    An experimental investigation of phenyl radical pyrolysis and the phenyl radical + acetylene reaction has been performed to clarify the role of different reaction mechanisms involved in the formation and growth of polycyclic aromatic hydrocarbons (PAHs) serving as precursors for soot formation. Experiments were conducted using GC/GC-MS diagnostics coupled to the high-pressure single-pulse shock tube present at the University of Illinois at Chicago. For the first time, comprehensive speciation of the major stable products, including small hydrocarbons and large PAH intermediates, was obtained over a wide range of pressures (25-60 atm) and temperatures (900-1800 K) which encompass the typical conditions in modern combustion devices. The experimental results were used to validate a comprehensive chemical kinetic model which provides relevant information on the chemistry associated with the formation of PAH compounds. In particular, the modeling results indicate that the o-benzyne chemistry is a key factor in the formation of multi-ring intermediates in phenyl radical pyrolysis. On the other hand, the PAHs from the phenyl + acetylene reaction are formed mainly through recombination between single-ring aromatics and through the hydrogen abstraction/acetylene addition mechanism. Polymerization is the common dominant process at high temperature conditions.

  18. Tricyclic antidepressant-induced lipidosis in human peripheral monocytes in vitro, as well as in a monocyte-derived cell line, as monitored by spectrofluorimetry and flow cytometry after staining with Nile red.

    Science.gov (United States)

    Xia, Z; Appelkvist, E L; DePierre, J W; Nässberger, L

    1997-05-15

    Human mono- and lymphocytes from peripheral blood and the monoblastoid cell line U-937 were used in this in vitro study of drug-induced lipidosis. Mono- and lymphocytes were exposed for 4 days to three different tricyclic antidepressants (TCAs), imipramine (25 microM), clomipramine (10 microM) and citalopram (80 microM). The lipophilic fluorophore Nile red, which stains intracellular lipid structures selectively, was used as a lipid probe. Fluorescence microscopy, spectrofluorimetry and flow cytometry were used to detect cellular lipidosis, as verified by electron microscopy. Our results demonstrate that imipramine, clomipramine and citalopram induce lipidosis in monocytes and U-937 cells, but not in lymphocytes. An accurate quantitation of induced intracellular lipidosis can be achieved by spectrofluorimetric and flow cytometric analysis.

  19. Divergent Strategy for the Diastereoselective Synthesis of the Tricyclic 6,7-Diaryltetrahydro-6H-benzo[c]chromene Core via Pt(IV)-Catalyzed Cycloaddition of o-Quinone Methides and Olefin Ring-Closing Metathesis.

    Science.gov (United States)

    Tangdenpaisal, Kassrin; Chuayboonsong, Kanokpish; Ruchirawat, Somsak; Ploypradith, Poonsakdi

    2017-03-03

    A divergent strategy for the synthesis of the tricyclic 6,7-diaryltetrahydro-6H-benzo[c]chromene core was successfully developed. The 2,3-trans, 2,4-cis trisubstituted chroman moiety was formed via highly efficient and stereoselective Pt(IV)-catalyzed cycloaddition reactions of the corresponding quinone methides with chalcones. Subsequent steps provided the common diene alcohol, which underwent BF 3 ·Et 2 O-mediated Et 3 SiH reduction and olefin ring-closing metathesis (RCM) using Ru(II) catalysts. The sequence of the final two steps provided a handle to diversify the stereochemical outcomes at C6 as well as C10a.

  20. Protonation sites of aromatic compounds in (+) atmospheric pressure photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Hwan; Ahmed, Arif [Dept. of Chemistry, Kyungpoo k National University, Daegu (Korea, Republic of)

    2017-02-15

    Reaction enthalpy of hydrogen transfer reactions of aromatic compounds has been observed to be greatly affected by the exact location of the protonation site. Therefore, to clearly identify the protonation location, each candidate protonation site for 43 aromatic compounds were theoretically determined and their location was compared with that determined based on experimental MS data. Only the basic nitrogen atom is favorable as a protonation site for pyridine-type aromatic compounds, whereas carbon atoms are preferable for the protonation of pyrrole-type compounds. The most favorable protonation sites for aniline or methylated aniline-type aromatic compounds are either the nitrogen atom in the amine group or the carbon atom at the para-position to the amine group. Like pyrrole-type compounds, aromatic compounds with amine groups also favor protonation at the carbon atom instead of at the nitrogen atom. In addition, hydrocarbons having an anthracene structural motif without heteroatoms produced higher or equal percentages of protonated ions compared to that achieved with molecular ions. The results of this study can be used to improve the analyses of aromatic compounds.

  1. Aromatization of n-octane over Pd/C catalysts

    KAUST Repository

    Yin, Mengchen

    2013-01-01

    Gas-phase aromatization of n-octane was investigated using Pd/C catalyst. The objectives were to: (1) determine the effects of temperature (400-600 °C), weight hourly space velocity (WHSV) (0.8-∞), and hydrogen to hydrocarbon molar ratio (MR) (0-6) on conversion, selectivity, and yield (2) compare the activity of Pd/C with Pt/C and Pt/KL catalysts and (3) test the suitability of Pd/C for aromatization of different alkanes including n-hexane, n-heptane, and n-octane. Pd/C exhibited the best aromatization performance, including 54.4% conversion and 31.5% aromatics yield at 500 °C, WHSV = 2 h-1, and a MR of 2. The Pd/C catalyst had higher selectivity towards the preferred aromatics including ethylbenzene and xylenes, whereas Pt/KL had higher selectivity towards benzene and toluene. The results were somewhat consistent with adsorbed n-octane cyclization proceeding mainly through the six-membered ring closure mechanism. In addition, Pd/C was also capable of catalyzing aromatization of n-hexane and n-heptane. © 2012 Elsevier Ltd. All rights reserved.

  2. Halogen-aromatic π-interactions modulate inhibitor residence time.

    Science.gov (United States)

    Heroven, Christina; Georgi, Victoria; Ganotra, Gaurav K; Brennan, Paul E; Wolfreys, Finn; Wade, Rebecca C; Fernández-Montalván, Amaury E; Chaikuad, Apirat; Knapp, Stefan

    2018-03-30

    Prolonged drug residence times may result in longer lasting drug efficacy, improved pharmacodynamic properties and "kinetic selectivity" over off-targets with fast drug dissociation rates. However, few strategies have been elaborated to rationally modulate drug residence time and thereby to integrate this key property into the drug development process. Here, we show that the interaction between a halogen moiety on an inhibitor and an aromatic residue in the target protein can significantly increase inhibitor residence time. By using the interaction of the serine/threonine kinase haspin with 5-iodotubercidin (5-iTU) derivatives as a model for an archetypal active state (type I) kinase-inhibitor binding mode, we demonstrate that inhibitor residence times markedly increase with the size and polarizability of the halogen atom. This key interaction is dependent on the interactions with an aromatic residue in the gatekeeper position and we observe this interaction in other kinases with an aromatic gatekeeper residue. We provide a detailed mechanistic characterization of the halogen-aromatic π interactions in the haspin-inhibitor complexes by means of kinetic, thermodynamic, and structural measurements along with binding energy calculations. Since halogens are frequently used in drugs and aromatic residues are often present in the binding sites of proteins, our results provide a compelling rationale for introducing aromatic-halogen interactions to prolong drug-target residence times. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. The formation of aromatics and PAH's in laminar flames

    International Nuclear Information System (INIS)

    Marinov, N M; Pitz, W J; Westbrook, C K

    1999-01-01

    The formation of aromatics and PAH's is an important problem in combustion. These compounds are believed to contribute to the formation of soot whose emission from diesel engines is regulated widely throughout the industrial world. Additionally, the United States Environmental Protection Agency regulates the emission of many aromatics and PAH species from stationary industrial burners, under the 1990 Clean Air Act Amendments. The above emission regulations have created much interest in understanding how these species are formed in combustion systems. Much previous work has been done on aromatics and PAH's. The work is too extensive to review here, but is reviewed in Reference 1. A few recent developments are highlighted here. McEnally, Pfefferle and coworkers have studied aromatic, PAH and soot formation in a variety of non-premixed flames with hydrocarbon additives[2-4]. They found additives that contain a C5 ring increase the concentration of aromatics and soot[4]. Howard and coworkers have studied the formation of aromatic and PAH's in low pressure, premixed, laminar hydrocarbon flames. They found the cyclopentadienyl radical to be a key species in naphthalene formation in a fuel-rich, benzene/Ar/O2 flame[5

  4. Petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) in Hong Kong marine sediments

    International Nuclear Information System (INIS)

    Zheng, G.J.; Richardson, B.J.

    1999-01-01

    A total of 20 surficial sediment samples, obtained from Hong Kong coastal waters, were analysed for petroleum hydrocarbons (PHCs) and a suite of 15 polycyclic aromatic hydrocarbons (PAHs). The results indicate that Hong Kong coastal sediments are often seriously polluted with petroleum related hydrocarbons. This is especially so in heavily urbanised or industrialized localities, such as Kowloon Bay (Victoria Harbour), Tsing Yi North and Tolo Harbour. Petroleum hydrocarbon pollutants in marine sediments are believed to be mainly derived from the transportation of oil, shipping activities, spillages, and industrial, stormwater and waste wastewater discharge. The ratio of unresolved complex mixture (UCM) to n-alkanes, carbon preference index (CPI), and n-C 16 values indicate that the main contribution to petroleum hydrocarbon contamination is via oil and its products. Pollutant sources appear to be stable and continuing when compared with previous data. (author)

  5. Selective side-chain oxidation of alkyl aromatic compounds catalyzed by cerium modified silver catalysts

    DEFF Research Database (Denmark)

    Beier, Matthias Josef; Schimmoeller, Bjoern; Hansen, Thomas Willum

    2010-01-01

    . In addition, flame-made catalysts were more stable against silver leaching compared to the impregnated catalysts. The structure of the silver catalysts was studied in detail both by X-ray absorption spectroscopy and transmission electron microscopy suggesting metallic silver to be required for catalytic......Silver supported on silica effectively catalyzes the aerobic side-chain oxidation of alkyl aromatic compounds under solvent-free conditions. Toluene, p-xylene, ethylbenzene and cumene were investigated as model substrates. Typically, the reaction was performed at ambient pressure; only for toluene...... an elevated pressure was required. Carboxylic acids, such as benzoic acid or p-toluic acid, additionally increased the reaction rate while CeO2 could act both as a promoter and an inhibitor depending on the substrate and the reaction conditions. Silver catalysts were prepared both by standard impregnation...

  6. Differential immunomodulatory responses to nine polycyclic aromatic hydrocarbons applied by passive dosing

    DEFF Research Database (Denmark)

    Oostingh, Gertie J.; Smith, Kilian E. C.; Tischler, Ulrike

    2015-01-01

    and stable dissolved concentrations during in vitro testing, and was applied to control and maintain freely dissolved concentrations of polycyclic aromatic hydrocarbons (PAHs) at levels up to their aqueous solubility limit. The immunomodulatory effects of 9 different PAHs at aqueous solubility on human...... bronchial epithelial cells were determined by analysing the cytoldne promoter expression of 4 different inflammatory cytokines using stably transfected recombinant A549 cell lines. Diverse immunomodulatory responses were found with the highest induction observed for the most hydrophobic PAHs chrysene, benzo...... at any of the concentrations tested. Overall, this study shows that (1) immunomodulatory effects of PAHs can be studied in vitro at controlled freely dissolved concentrations, (2) the most hydrophobic PAHs were the strongest inducers and (3) induction was often higher at lower exposure levels...

  7. Atmospheric behaviors of particulate-bound polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in Beijing, China from 2004 to 2010

    OpenAIRE

    Tang, Ning; Suzuki, Genki; Morisaki, Hiroshi; Tokuda, Takahiro; Yang, Xiaoyang; Zhao, Lixia; Lin, Jinming; Kameda, Takayuki; Toriba, Akira; Hayakawa, Kazuichi

    2017-01-01

    Airborne particulates were collected at an urban site (site 1) from 2004 to 2010 and at a suburban site (site 2) in 2010 in Beijing. Nine polycyclic aromatic hydrocarbons (PAHs) and five nitropolycyclic aromatic hydrocarbons (NPAHs) in the airborne particulates were determined by HPLC with fluorescence and chemiluminescence detection, respectively. The concentrations of PAHs and NPAHs were higher in heating season than in non-heating season at the two sites. Both the concentrations of PAHs an...

  8. Radiation-stable polyolefin compositions

    International Nuclear Information System (INIS)

    Rekers, J.W.

    1986-01-01

    This invention relates to compositions of olefinic polymers suitable for high energy radiation treatment. In particular, the invention relates to olefinic polymer compositions that are stable to sterilizing dosages of high energy radiation such as a gamma radiation. Stabilizers are described that include benzhydrol and benzhydrol derivatives; these stabilizers may be used alone or in combination with secondary antioxidants or synergists

  9. Monitoring of stable glaucoma patients

    NARCIS (Netherlands)

    K.M. Holtzer-Goor (Kim); N.S. Klazinga (Niek); M.A. Koopmanschap (Marc); H.G. Lemij (Hans); T. Plochg; E. van Sprundel (Esther)

    2010-01-01

    textabstractA high workload for ophthalmologists and long waiting lists for patients challenge the organization of ophthalmic care. Tasks that require less specialized skills, like the monitoring of stable (well controlled) glaucoma patients could be substituted from ophthalmologists to other

  10. Polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in particulates emitted by motorcycles

    International Nuclear Information System (INIS)

    Pham, Chau Thuy; Kameda, Takayuki; Toriba, Akira; Hayakawa, Kazuichi

    2013-01-01

    We determined eleven PAHs and four NPAHs in particulates and regulated pollutants (CO, CO 2 , HC, NO x , PM) exhausted from motorcycles to figure out the characteristics of motorcycle exhausts. Fluoranthene and pyrene accounted for more than 50% of the total detected PAHs. Among four detected NPAHs, 6-nitrochrysene and 7-nitrobenz[a]anthracene were the predominant NPAHs and were highly correlated relationship with their parent PAHs (R = 0.93 and 0.97, respectively). The PM and HC emissions tended to be close to the PAH emissions. NO x and NPAHs were negatively correlated. Despite their small engine size, motorcycles emitted much more PM and PAHs, showed stronger PAH-related carcinogenicity and indirect-acting mutagenicity, but weaker NPAH-related direct-acting mutagenic potency than automobiles. This is the first study to analyze both PAHs and NPAHs emitted by motorcycles, which could provide useful information to design the emission regulations and standards for motorcycles such as PM. -- Highlights: ► We characterized PAHs and NPAHs distribution in motorcycle exhausts. ► NPAHs concentrations were about three orders of magnitude lower than those of PAHs. ► We found larger amounts of PM and PAHs in exhaust of motorcycles than of automobiles. ► Motorcycles showed stronger PAH-related toxicity than automobiles. ► Motorcycles showed weaker NPAH-related direct-acting mutagenicity than automobiles. -- Control polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbon in particulates emitted by motorcycles due to their toxic potency

  11. Identification and accumulation of aromatic sensitizers in fish from paper recycling in Japan.

    Science.gov (United States)

    Terasaki, Masanori; Jozuka, Kazuhiko; Makino, Masakazu

    2012-06-01

    Aromatic sensitizers and related compounds (SRCs) originating from thermal recording material as impurities in waste paper have been detected in aquatic environments near cities where the paper industry is flourishing. In the present study, the levels of exposure to such SRCs and the stable isotope ratios (δ(13)C and δ(15)N) in different fish species (Konosirus punctatus, Takifugu niphobles, and Tribolodon hakonensis) were analyzed. These fish species were collected from the vicinity of waste paper recycling plants in Japan. Eleven SRCs were identified in fish muscle at total concentration levels (ΣSRCs) of 64 to 818 ng/g wet weight (mean 181 ng/L wet wt). The dominant SRCs in the fish samples were 1,1-di(4-methylphenyl)ethane, 1,2-bis(3-methylphenoxy)ethane, and 1,4-dibenzyloxybenzene. Stable isotope ratios showed that, although three species feed on the same trophic level, K. punctatus and T. niphobles live in waters farther offshore than those in which T. hakonensis live. The contributions of various factors to the accumulation were also assessed. The lipid content (r(2) = 0.512, p < 0.001) was found to be the significant factor that influenced accumulation of SRCs in fish. The results also revealed significant positive correlation between the accumulation patterns and SRC components in water (r(2) = 0.512-0.658, all p values <0.05), but they showed negative correlations between the SRCs in fish and log K(OW) values. This suggests that the aqueous route is the predominant route for the accumulation of SRCs in fish. This is the first study on the accumulation of aromatic sensitizers in aquatic biota. Copyright © 2012 SETAC.

  12. Arginine-aromatic interactions and their effects on arginine-induced solubilization of aromatic solutes and suppression of protein aggregation

    KAUST Repository

    Shah, Dhawal

    2011-09-21

    We examine the interaction of aromatic residues of proteins with arginine, an additive commonly used to suppress protein aggregation, using experiments and molecular dynamics simulations. An aromatic-rich peptide, FFYTP (a segment of insulin), and lysozyme and insulin are used as model systems. Mass spectrometry shows that arginine increases the solubility of FFYTP by binding to the peptide, with the simulations revealing the predominant association of arginine to be with the aromatic residues. The calculations further show a positive preferential interaction coefficient, Γ XP, contrary to conventional thinking that positive Γ XP\\'s indicate aggregation rather than suppression of aggregation. Simulations with lysozyme and insulin also show arginine\\'s preference for aromatic residues, in addition to acidic residues. We use these observations and earlier results reported by us and others to discuss the possible implications of arginine\\'s interactions with aromatic residues on the solubilization of aromatic moieties and proteins. Our results also highlight the fact that explanations based purely on Γ XP, which measures average affinity of an additive to a protein, could obscure or misinterpret the underlying molecular mechanisms behind additive-induced suppression of protein aggregation. © 2011 American Institute of Chemical Engineers (AIChE).

  13. The proton transfer reaction in malonaldehyde derivatives: Substituent effects and quasi-aromaticity of the proton bridge

    International Nuclear Information System (INIS)

    Palusiak, Marcin; Simon, Silvia; Sola, Miquel

    2007-01-01

    The proton transfer in malonaldehyde and in some of its derivatives have been considered in order to study the interrelation between the reaction barrier and the π-delocalization in the quasi-ring. A set of simple and mostly common substituents having different properties in resonance effect according to values of substituents constants were chosen in order to simulate the influence of substitution in position 2 or in position 1 (or 3) of malonaldehyde on the quasi-aromaticity and H-bonding. The following substituents have been taken into consideration: NO, NO 2 , CN, CHO, F, H, CH 3 , OCH 3 , OH, and NH 2 . Our results show that when the substituent is attached at position 2 of the quasi-ring, the resonance effect predominates over the field/inductive effect which leads to changes in H-bonding and quasi-aromaticity of the ring motif, while in the case of 1(3) substitution the field/inductive effect is significantly more effective influencing the HB strength, and thus, the proton transfer barrier. Somehow counterintuitively, for the 1(3) substituted systems, the most stable isomer is the one having the weakest HB and lower aromaticity. The reason for this surprising behaviour is discussed

  14. Investigation of the gas-phase hydrogen/deuterium exchange behavior of aromatic dicarboxylic acids in a quadrupole ion trap

    Science.gov (United States)

    Chipuk, Joseph E.; Brodbelt, Jennifer S.

    2007-11-01

    Gas-phase hydrogen/deuterium (H/D) exchange reactions of four deprotonated aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid and 2,6-naphthalic acid) with D2O were performed in a quadrupole ion trap mass spectrometer. Experimental results showed significant differences in the rate and extent of exchange when the relative position of the carboxylic acid groups varied. Spontaneous and near complete exchange of one aromatic hydrogen atom occurred when the carboxylic acid groups were in the meta-position, whereas no additional exchange was observed for either the ortho- or para-isomers or for the structurally similar naphthalic acid. Computational investigations support the participation of several possible exchange mechanisms with the contribution of each relying heavily on the relative orientation of the acid moieties. A relay mechanism that bridges the deprotonation site and the labile hydrogen site appears to be responsible for the H/D exchange of not only the labile hydrogen atom of isophthalic acid, but also for the formation of a stable carbanion and corresponding subsequent exchange of one aromatic hydrogen atom. The impact of hydrogen bonding on the relay mechanism is demonstrated by the reaction of phthalic acid as the extent and rate of reaction are greatly retarded by the favorable interaction of the two carboxylic acid groups. Finally, a flip-flop mechanism is likely responsible for the exchange of both terephthalic acid and 2,6-naphthalic acid where the reactive sites are too remote for exchange via relay.

  15. An energetic measure of aromaticity and antiaromaticity based on the Pauling-Wheland resonance energies.

    Science.gov (United States)

    Mo, Yirong; von Ragué Schleyer, Paul

    2006-02-20

    Various criteria based on geometric, energetic, magnetic, and electronic properties are employed to delineate aromatic and antiaromatic systems. The recently proposed block-localized wave function (BLW) method evaluates the original Pauling-Wheland adiabatic resonance energy (ARE), defined as the energy difference between the real conjugated system and the corresponding virtual most stable resonance structure. The BLW-derived ARE of benzene is 57.5 kcal mol(-1) with the 6-311+G** basis set. Kistiakowsky's historical experimental evaluation of the stabilization energy of benzene (36 kcal mol(-1)), based on heats of hydrogenation, seriously underestimates this quantity due to the neglect of the partially counterbalancing hyperconjugative stabilization of cyclohexene, employed as the reference olefin (three times) in Kistiakowsky's evaluation. Based instead on the bond-separation-energy reaction involving ethene, which has no hyperconjugation, as well as methane and ethane, the experimental resonance energy of benzene is found to be 65.0 kcal mol(-1). We derived the "extra cyclic resonance energy" (ECRE) to characterize and measure the extra stabilization (aromaticity) of conjugated rings. ECRE is the difference between the AREs of a fully cyclically conjugated compound and an appropriate model with corresponding, but interrupted (acyclic) conjugation. Based on 1,3,5-hexatriene, which also has three double bonds, the ECRE of benzene is 36.7 kcal mol(-1), whereas based on 1,3,5,7-octatetraene, which has three diene conjugations, the ECRE of benzene is 25.7 kcal mol(-1). Computations on a series of aromatic, nonaromatic, and antiaromatic five-membered rings validate the BLW-computed resonance energies (ARE). ECRE data on the five-membered rings (derived from comparisons with acyclic models) correlate well with nucleus-independent chemical shift (NICS) and other quantitative aromaticity criteria. The ARE of cyclobutadiene is almost the same as butadiene but is 10.5 kcal

  16. Novel platinum/KL catalysts for the aromatization of N-hexane

    Science.gov (United States)

    Jacobs, Gary

    A number of studies were conducted to understand the underlying reasons for the uniqueness of Pt/KL for its high activity and selectivity for benzene production. Catalytic screening of basic supported Pt catalysts revealed that aromatization passes through dehydrogenated intermediates, including hexenes. Pt/KL was found to more efficiently convert hexenes to benzene than nonmicroporous basic supported Pt catalysts. The role of L-zeolite was found to protect the Pt clusters from bimolecular pathways leading to the deposition of coke on the surface of the Pt. Sulfur deactivates Pt/KL by agglomeration of Pt clusters and the formation of Pt-S, breaking up Pt ensembles required for aromatization. The role of morphology of Pt inside the L-zeolite channels was found to play an important role on catalytic stability. Series of catalysts were prepared by incipient wetness and vapor phase impregnation and characterized by a variety of techniques, including H2 chemisorption, EXAFS, FTIR of adsorbed CO, MCP ring opening, and TEM and tested by both pulse and flow mode n-hexane reaction. While both catalysts exhibited small Pt clusters inside the channels of the L-zeolite, the IWI had a fraction near the surface region large enough to block channels. Under reaction, the IWI catalysts deactivated to about half the initial activity. However, VPI had Pt clusters small enough to reside in the lobes of the ellipsoid cages of the channels; these catalysts were remarkably stable. Addition of a small amount of thulium to KL was found to aid in dispersing the Pt. Using TPO, thulium was found to act a sulfur getter. Electronic modification to Pt by exchanging the zeolite cation from potassium to lithium was studied by shape resonance XANES, microcalorimetry, and pulse neopentane hydrogenolysis. Addition of lithium resulted in a shift of the Fermi level of Pt away from the antibonding state of Pt-H, strengthening the chemisorption bond. Increased hydrogenolysis rates were observed for both

  17. Biodegradation Of Polycyclic Aromatic Hydrocarbons In Petroleum Oil Contaminating The Environment

    International Nuclear Information System (INIS)

    Partila, A.M.

    2013-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in urban atmospheres (Chen et al., 2013). PAHs enter the environment via incomplete combustion of fossil fuels and accidental leakage of petroleum products, and as components of products such as creosote (Muckian et al., 2009). Due to PAHs carcinogenic activity, they have been included in the European Union (EU) and the Environmental Protection Agency (EPA) priority pollutant lists. Human exposure to PAHs occurs in three ways, inhalation, dermal contact and consumption of contaminated foods, which account for 88-98% of such contamination; in other words, diet is the major source of human exposure to these contaminants (Rey-Salgueiro et al., 2008). Both the World Health Organization and the UK Expert Panel on Air Quality Standards (EPAQS) have considered benzo(a)pyrene (BaP) as a marker of the carcinogenic potency of the polycyclic aromatic hydrocarbons (PAH) mixture (Delgado-Saborit et al., 2011). Polycyclic aromatic and heavier aliphatic hydrocarbons, which have a stable recalcitrant molecular structure, exhibit high hydrophobicity and low aqueous solubility, are not readily removed from soil through leaching and volatilization (Brassington et al., 2007). The hydrophobicity of PAHs limits desorption to the aqueous phase (Donlon et al., 2002). Six main ways of dissipation, i.e. disappearance, are recognized in the environment: volatilization, photooxidation, Aim of the Work chemical oxidation, sorption, leaching and biodegradation. Microbial degradation is considered to be the main process involved in the dissipation of PAH (Yuan et al., 2002). Thus, more and more research interests are turning to the biodegradation of PAHs. Some microorganisms can utilize PAHs as a source of carbon and energy so that PAHs can be degraded to carbon dioxide and water, or transformed to other nontoxic or low-toxic substances (Perelo, 2010). Compared with other physical and chemical methods such as combustion

  18. Fate of polynuclear aromatic hydrocarbons in soil

    International Nuclear Information System (INIS)

    Bulman, T.L.; Lesage, S.; Fowlie, P.; Webber, M.D.

    1987-01-01

    A study was performed on the persistence of selected polynuclear aromatic hydrocarbons (PAH's) in soil. Two incubation studies were performed. In the first, a mixture of eight PAH's were added to unacclimated soil at levels of 5 and 50 mg/kg and the concentrations were monitored with time. In the second, C 14 -labelled benzo(a)pyrene or anthracene was added to soil incubated in biometer flasks. Microbial degradation, physical and chemical degradation, volatilization and binding were assessed as mechanisms affecting benzo(a)pyrene and anthracene in soil. The disappearance of PAH's appeared to be related to molecular weight, water solubility, volatility and adsorptivity to soil. The loss during this initial period approximated first order kinetics, in some cases following a lag period. The remaining 2-6% of the added PAH's, however, was lost at a much reduced rate. With the 50 mg/kg level of application, reduced rates of disappearance in later stages resulted in levels five to ten times the background concentration which persisted throughout the 400 days. Degradation of phenanthrene, anthracene, fluoranthene and pyrene at the 5 mg/kg application rate, however, resulted in concentrations close to background levels within 400 days. Either a model other than first order or a combination of two models was required to adequately describe the loss of 99% of the added PAH's. The mechanisms leading to a decrease in PAH concentration, identified through the use of C 14 labelling, were predominantly volatilization and adsorption to soil solids for anthracene and adsorption to soil solids for benzo(a)pyrene. Microbial transformation of benzo(a)pyrene was minimal. 17 refs., 10 figs., 4 tabs

  19. Polycyclic Aromatic Hydrocarbons in Fine Particulate Matter ...

    Science.gov (United States)

    This study measured polycyclic aromatic hydrocarbon (PAH) composition in particulate matter emissions from residential cookstoves. A variety of fuel and cookstove combinations were examined, including: (i) liquid petroleum gas (LPG), (ii) kerosene in a wick stove, (iii) wood (10% and 30% moisture content on a wet basis) in a forced-draft fan stove, and (iv) wood in a natural-draft rocket cookstove. LPG combustion had the highest thermal efficiency (~57%) and the lowest PAH emissions per unit fuel energy, resulting in the lowest PAH emissions per useful energy delivered (MJd). The average benzo[a]pyrene (B[a]P) emission factor for LPG was 0.842 µg/MJd; the emission rate was 0.043 µg/min. The highest PAH emissions were from wood burning in the natural-draft stove (209-700 µg B[a]P/MJd). PAH emissions from kerosene were significantly lower than those from the wood burning in the natural-draft cookstove, but higher than those from LPG. It is expected that in rural regions where LPG and kerosene are unavailable or unaffordable, the forced-draft fan stove may be an alternative because its emission factor (5.17-8.07 µg B[a]P/MJd) and emission rate (0.52-0.57 µg/min) are similar to kerosene (5.36 µg B[a]P/MJd and 0.45 µg/min). Compared with wood combustion emissions, LPG stoves emit less total PAH emissions and less fractions of high molecular weight PAHs. Relatively large variations in PAH emissions from LPG call for additional future tests to identify the major

  20. Structures, stabilities, aromaticity, and electronic properties of C66 fullerene isomers, anions (C662-, C664-, C666-), and metallofullerenes (Sc2-C66)

    International Nuclear Information System (INIS)

    Cui Yanhong; Tian, Wei Quan; Feng Jikang; Chen Deli

    2010-01-01

    Among all the 4478 classical isomers of C 66 , C 66 (C s :0060) with the lowest number of pentagon-pentagon fusions was predicted to be the most stable isomer, followed by isomers C 66 (C 2v :0011) and C 66 (C 2 :0083). The infrared spectra and aromaticity of the most stable isomers were predicted. The relative stabilities of C 66 isomers change with charges or doping of metals. The structures and relative stabilities of the most stable metallofullerenes were delineated and compared with experiment. Sc 2 -C 66 (C 2 :0083) was predicted to be the most stable metallofullerene, although Sc 2 -C 66 (C 2v :0011) was observed. Charge-transfer from Sc 2 to the fused pentagons and the bonding between these two moieties significantly decrease the strain energies caused by the pair of fused pentagons thereby stabilizing the fullerene cage.

  1. Mechanistic Investigation into the Decarboxylation of Aromatic Carboxylic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Britt, P F; Buchanan, III, A C; Eskay, T P; Mungall, W S

    1999-08-22

    It has been proposed that carboxylic acids and carboxylates are major contributors to cross-linking reactions in low-rank coals and inhibit its thermochemical processing. Therefore, the thermolysis of aromatic carboxylic acids was investigated to determine the mechanisms of decarboxylation at temperatures relevant to coal processing, and to determine if decarboxylation leads to cross-linking (i.e., formation of more refractory products). From the thcrmolysis of simple and polymeric coal model compounds containing aromatic carboxylic acids at 250-425 °C, decarboxylation was found to occur primarily by an acid promoted ionic pathway. Carboxylate salts were found to enhance the decarboxylation rate, which is consistent with the proposed cationic mechanism. Thermolysis of the acid in an aromatic solvent, such as naphthalene, produced a small amount of arylated products (~5 mol%)), which constitute a low-temperature cross-link. These arylated products were formed by the rapid decomposition of aromatic anhydrides, which are in equilibrium with the acid. These anhydrides decompose by a free radical induced decomposition pathway to form atyl radicals that can add to aromatic rings to form cross-links or abstract hydrogen. Large amounts of CO were formed in the thennolysis of the anhydrides which is consistent with the induced decomposition pathway. CO was also formed in the thermolysis of the carboxylic acids in aromatic solvents which is consistent with the formation and decomposition of the anhydride. The formation of anhydride linkages and cross-links was found to be very sensitive to the reactions conditions. Hydrogen donor solvents, such as tetralin, and water were found to decrease the formation of arylated products. Silar reaction pathways were also found in the thermolysis of a polymeric model that contained aromatic carboxylic acids. In this case, anhydride formation and decomposition produced an insoluble polymer, while the O-methylated polymer and the non

  2. Toward Practical Secure Stable Matching

    Directory of Open Access Journals (Sweden)

    Riazi M. Sadegh

    2017-01-01

    Full Text Available The Stable Matching (SM algorithm has been deployed in many real-world scenarios including the National Residency Matching Program (NRMP and financial applications such as matching of suppliers and consumers in capital markets. Since these applications typically involve highly sensitive information such as the underlying preference lists, their current implementations rely on trusted third parties. This paper introduces the first provably secure and scalable implementation of SM based on Yao’s garbled circuit protocol and Oblivious RAM (ORAM. Our scheme can securely compute a stable match for 8k pairs four orders of magnitude faster than the previously best known method. We achieve this by introducing a compact and efficient sub-linear size circuit. We even further decrease the computation cost by three orders of magnitude by proposing a novel technique to avoid unnecessary iterations in the SM algorithm. We evaluate our implementation for several problem sizes and plan to publish it as open-source.

  3. Towards stable acceleration in LINACS

    CERN Document Server

    Dubrovskiy, A D

    2014-01-01

    Ultra-stable and -reproducible high-energy particle beams with short bunches are needed in novel linear accelerators and, in particular, in the Compact Linear Collider CLIC. A passive beam phase stabilization system based on a bunch compression with a negative transfer matrix element R56 and acceleration at a positive off-crest phase is proposed. The motivation and expected advantages of the proposed scheme are outlined.

  4. Global simulation of aromatic volatile organic compounds in the atmosphere

    Science.gov (United States)

    Cabrera Perez, David; Taraborrelli, Domenico; Pozzer, Andrea

    2015-04-01

    Among the large number of chemical compounds in the atmosphere, the organic group plays a key role in the tropospheric chemistry. Specifically the subgroup called aromatics is of great interest. Aromatics are the predominant trace gases in urban areas due to high emissions, primarily by vehicle exhausts and fuel evaporation. They are also present in areas where biofuel is used (i.e residential wood burning). Emissions of aromatic compounds are a substantial fraction of the total emissions of the volatile organic compounds (VOC). Impact of aromatics on human health is very important, as they do not only contribute to the ozone formation in the urban environment, but they are also highly toxic themselves, especially in the case of benzene which is able to trigger a range of illness under long exposure, and of nitro-phenols which cause detrimental for humans and vegetation even at very low concentrations. The aim of this work is to assess the atmospheric impacts of aromatic compounds on the global scale. The main goals are: lifetime and budget estimation, mixing ratios distribution, net effect on ozone production and OH loss for the most emitted aromatic compounds (benzene, toluene, xylenes, ethylbenzene, styrene and trimethylbenzenes). For this purpose, we use the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model to build the global atmospheric budget for the most emitted and predominant aromatic compounds in the atmosphere. A set of emissions was prepared in order to include biomass burning, vegetation and anthropogenic sources of aromatics into the model. A chemical mechanism based on the Master Chemical Mechanism (MCM) was developed to describe the chemical oxidation in the gas phase of these aromatic compounds. MCM have been reduced in terms of number of chemical equation and species in order to make it affordable in a 3D model. Additionally other features have been added, for instance the production of HONO via ortho

  5. Dipolar Quinoidal Acene Analogues as Stable Isoelectronic Structures of Pentacene and Nonacene

    KAUST Repository

    Shi, Xueliang

    2015-10-08

    Quinoidal thia-acene analogues, as the respective isoelectronic structures of pentacene and nonacene, were synthesized and an unusual 1,2-sulfur migration was observed during the Friedel-Crafts alkylation reaction. The analogues display a closed-shell quinoidal structure in the ground state with a distinctive dipolar character. In contrast to their acene isoelectronic structures, both compounds are stable because of the existence of more aromatic sextet rings, a dipolar character, and kinetic blocking. They exhibit unique packing in single crystals resulting from balanced dipole-dipole and [C-H⋯π]/[C-H⋯S] interactions.

  6. The mutagenic potential of high flash aromatic naphtha.

    Science.gov (United States)

    Schreiner, C A; Edwards, D A; McKee, R H; Swanson, M; Wong, Z A; Schmitt, S; Beatty, P

    1989-06-01

    Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent--high-flash aromatic naphtha. A program was initiated to assess the toxicological properties of high-flash aromatic naphtha since there may be human exposure through inhalation or external body contact. The current study was conducted partly to assess the potential for mutagenic activity and also to assist in an assessment of carcinogenic potential. The specific tests utilized included the Salmonella/mammalian microsome mutagenicity assay, the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) forward mutation assay in CHO cells, in vitro chromosome aberration and sister chromatid exchange (SCE) assays in CHO cells, and an in vivo chromosome aberration assay in rat bone marrow.

  7. Degradation of aromatic compounds in plants grown under aseptic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mithaishvili, T.; Ugrekhelidze, D.; Tsereteli, B.; Sadunishvili, T.; Kvesitadze, G. [Durmishidze Inst. of Biochemistry and Biotechnology, Academy of Sciences of Georgia, Tbilisi (Georgia); Scalla, R. [Lab. des Xenobiotiques, INRA, Toulouse (France)

    2005-02-01

    The aim of the work is to investigate the ability of higher plants to absorb and detoxify environmental pollutants - aromatic compounds via aromatic ring cleavage. Transformation of {sup 14}C specifically labelled benzene derivatives, [1-6-{sup 14}C]-nitrobenzene, [1-6-{sup 14}C]-aniline, [1-{sup 14}C]- and [7-{sup 14}C]-benzoic acid, in axenic seedlings of maize (Zea mays L.), kidney bean (Phaseolus vulgaris L.), pea (Pisum sativum L.) and pumpkin (Cucurbita pepo L.) were studied. After penetration in plants, the above xenobiotics are transformed by oxidative or reductive reactions, conjugation with cell endogenous compounds, and binding to biopolymers. The initial stage of oxidative degradation consists in hydroxylation reactions. The aromatic ring can then be cleaved and degraded into organic acids of the Krebs cycle. Ring cleavage is accompanied by {sup 14}CO{sub 2} evolution. Aromatic ring cleavage in plants has thus been demonstrated for different xenobiotics carrying different substitutions on their benzene ring. Conjugation with low molecular peptides is the main pathway of aromatic xenobiotics detoxification. Peptide conjugates are formed both by the initial xenobiotics (except nitrobenzene) and by intermediate transformation products. The chemical nature of the radioactive fragment and the amino acid composition of peptides participating in conjugation were identified. (orig.)

  8. Aromaticity in Group 14 homologues of the cyclopropenylium cation.

    Science.gov (United States)

    Fernández, Israel; Duvall, Matthew; I-Chia Wu, Judy; Schleyer, Paul von Ragué; Frenking, Gernot

    2011-02-11

    The nature of the bonding and the aromaticity of the heavy Group 14 homologues of cyclopropenylium cations E3H3+ and E2H2E'H+ (E, E' = C-Pb) have been investigated systematically at the BP86/TZ2P DFT level by using several methods. Aromatic stabilization energies (ASE) were evaluated from the values obtained from energy decomposition analysis (EDA) of charged acyclic reference molecules. The EDA-ASE results compare well with the extra cyclic resonance energy (ECRE) values given by the block localized wavefunction (BLW) method. Although all compounds investigated are Hückel 4n+2 π electron species, their ASEs indicate that the inclusion of Group 14 elements heavier than carbon reduces the aromaticity; the parent C3H3+ ion and Si2H2CH+ are the most aromatic, and Pb3H3+ is the least so. The higher energies for the cyclopropenium analogues reported in 1995 employed an isodesmic scheme, and are reinterpreted by using the BLW method. The decrease in the strength of both the π cyclic conjugation and the aromaticity in the order C ≫ Si>Ge>Sn>Pb agrees reasonably well with the trends given by the refined nucleus-independent chemical shift NICS(0)πzz index.

  9. Global atmospheric budget of simple monocyclic aromatic compounds

    Directory of Open Access Journals (Sweden)

    D. Cabrera-Perez

    2016-06-01

    Full Text Available The global atmospheric budget and distribution of monocyclic aromatic compounds is estimated, using an atmospheric chemistry general circulation model. Simulation results are evaluated with an ensemble of surface and aircraft observations with the goal of understanding emission, production and removal of these compounds.Anthropogenic emissions provided by the RCP database represent the largest source of aromatics in the model (≃ 23 TgC year−1 and biomass burning from the GFAS inventory the second largest (≃ 5 TgC year−1. The simulated chemical production of aromatics accounts for  ≃ 5 TgC year−1. The atmospheric burden of aromatics sums up to 0.3 TgC. The main removal process of aromatics is photochemical decomposition (≃ 27 TgC  year−1, while wet and dry deposition are responsible for a removal of  ≃ 4 TgC year−1.Simulated mixing ratios at the surface and elsewhere in the troposphere show good spatial and temporal agreement with the observations for benzene, although the model generally underestimates mixing ratios. Toluene is generally well reproduced by the model at the surface, but mixing ratios in the free troposphere are underestimated. Finally, larger discrepancies are found for xylenes: surface mixing ratios are not only overestimated but also a low temporal correlation is found with respect to in situ observations.

  10. Highly condensed aromatics and their connection to hydrogenation asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Boente, L.

    1944-11-22

    An attempt is made to account for the structure of asphalts and resins which arose in residues upon hydrogenation of coal. The main assumption is that most of these asphalts consisted of highly condensed aromatics, which are considered as derivatives of the substance coronene, which could be described as having the structure consisting of six benzene rings arranged around a central seventh benzene ring. Part of the discussion is speculative, but evidence is given which had led to that speculation. The asphalts had been very hard to analyze exactly, partly because of their very low solubility in most solvents and their very high boiling points. Possible mechanisms for the formation of such highly condensed aromatics during the hydrogenation process are described along with experimental work aimed in part at hydrogenating these aromatics and in part at producing them by condensation reactions of aluminum chloride on coronene. Some of the products of the condensation reactions even resembled coke or soot, while others were red substances which fluoresced green in phenanthrene solution. It is hypothesized that coronene could be looked upon as the basic nucleus for a whole series of highly condensed aromatic molecules, in the same way that benzene is looked upon as the basic nucleus for a whole series of aromatic compounds.

  11. SiRNAs conjugated with aromatic compounds induce RISC-mediated antisense strand selection and strong gene-silencing activity

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Takanori, E-mail: kubo-t@yasuda-u.ac.jp [Faculty of Pharmacy, Yasuda Women' s University, 6-13-1 Yasuhigashi, Asaminami-ku, Hiroshima 731-0153 (Japan); Yanagihara, Kazuyoshi [Faculty of Pharmacy, Yasuda Women' s University, 6-13-1 Yasuhigashi, Asaminami-ku, Hiroshima 731-0153 (Japan); Division of Genetics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Takei, Yoshifumi [Department of Biochemistry, Nagoya University Graduate School of Medicine, 65 Tsurumi-cho, Showa-ku, Nagoya 466-8550 (Japan); Mihara, Keichiro [Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Sato, Yuichiro; Seyama, Toshio [Faculty of Pharmacy, Yasuda Women' s University, 6-13-1 Yasuhigashi, Asaminami-ku, Hiroshima 731-0153 (Japan)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer SiRNAs conjugated with aromatic compounds (Ar-siRNAs) at 5 Prime -sense strand were synthesized. Black-Right-Pointing-Pointer Ar-siRNAs increased resistance against nuclease degradation. Black-Right-Pointing-Pointer Ar-siRNAs were thermodynamically stable compared with the unmodified siRNA. Black-Right-Pointing-Pointer High levels of cellular uptake and cytoplasmic localization were found. Black-Right-Pointing-Pointer Strong gene-silencing efficacy was exhibited in the Ar-siRNAs. -- Abstract: Short interference RNA (siRNA) is a powerful tool for suppressing gene expression in mammalian cells. In this study, we focused on the development of siRNAs conjugated with aromatic compounds in order to improve the potency of RNAi and thus to overcome several problems with siRNAs, such as cellular delivery and nuclease stability. The siRNAs conjugated with phenyl, hydroxyphenyl, naphthyl, and pyrenyl derivatives showed strong resistance to nuclease degradation, and were thermodynamically stable compared with unmodified siRNA. A high level of membrane permeability in HeLa cells was also observed. Moreover, these siRNAs exhibited enhanced RNAi efficacy, which exceeded that of locked nucleic acid (LNA)-modified siRNAs, against exogenous Renilla luciferase in HeLa cells. In particular, abundant cytoplasmic localization and strong gene-silencing efficacy were found in the siRNAs conjugated with phenyl and hydroxyphenyl derivatives. The novel siRNAs conjugated with aromatic compounds are promising candidates for a new generation of modified siRNAs that can solve many of the problems associated with RNAi technology.

  12. Sulfide Catalysts Supported on Porous Aromatic Frameworks for Naphthalene Hydroprocessing

    Directory of Open Access Journals (Sweden)

    Eduard Karakhanov

    2016-08-01

    Full Text Available This paper describes the first example of using porous aromatic frameworks as supports for sulfide catalysts for the hydrogenation of aromatic hydrocarbons. The synthesis of bimetallic Ni-W and Ni-Mo sulfides was performed by in situ decomposition of [(n-Bu4N]2[Ni(MeS42] (Me = W, Mo complexes, supported on mesoporous aromatic framework with a diamond-like structure. It is shown that the highest naphthalene conversions were achieved in the case of additional sulfidation with sulfur. After the reaction, catalysts were characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. The activity of synthesized catalysts has been studied using naphthalene as a model substrate. The materials used in this study were substantially active in hydrogenation and slightly in hydrocracking of naphthalene.

  13. Molecular insights into the enzyme promiscuity of an aromatic prenyltransferase.

    Science.gov (United States)

    Chen, Ridao; Gao, Bingquan; Liu, Xiao; Ruan, Feiying; Zhang, Yong; Lou, Jizhong; Feng, Keping; Wunsch, Carsten; Li, Shu-Ming; Dai, Jungui; Sun, Fei

    2017-02-01

    Aromatic prenyltransferases (aPTases) transfer prenyl moieties from isoprenoid donors to various aromatic acceptors, some of which have the rare property of extreme enzymatic promiscuity toward both a variety of prenyl donors and a large diversity of acceptors. In this study, we discovered a new aPTase, AtaPT, from Aspergillus terreus that exhibits unprecedented promiscuity toward diverse aromatic acceptors and prenyl donors and also yields products with a range of prenylation patterns. Systematic crystallographic studies revealed various discrete conformations for ligand binding with donor-dependent acceptor specificity and multiple binding sites within a spacious hydrophobic substrate-binding pocket. Further structure-guided mutagenesis of active sites at the substrate-binding pocket is responsible for altering the specificity and promiscuity toward substrates and the diversity of product prenylations. Our study reveals the molecular mechanism underlying the promiscuity of AtaPT and suggests an efficient protein engineering strategy to generate new prenylated derivatives in drug discovery applications.

  14. Classification of Malaysia aromatic rice using multivariate statistical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, A. H.; Adom, A. H.; Shakaff, A. Y. Md; Masnan, M. J.; Zakaria, A.; Rahim, N. A. [School of Mechatronic Engineering, Universiti Malaysia Perlis, Kampus Pauh Putra, 02600 Arau, Perlis (Malaysia); Omar, O. [Malaysian Agriculture Research and Development Institute (MARDI), Persiaran MARDI-UPM, 43400 Serdang, Selangor (Malaysia)

    2015-05-15

    Aromatic rice (Oryza sativa L.) is considered as the best quality premium rice. The varieties are preferred by consumers because of its preference criteria such as shape, colour, distinctive aroma and flavour. The price of aromatic rice is higher than ordinary rice due to its special needed growth condition for instance specific climate and soil. Presently, the aromatic rice quality is identified by using its key elements and isotopic variables. The rice can also be classified via Gas Chromatography Mass Spectrometry (GC-MS) or human sensory panels. However, the uses of human sensory panels have significant drawbacks such as lengthy training time, and prone to fatigue as the number of sample increased and inconsistent. The GC–MS analysis techniques on the other hand, require detailed procedures, lengthy analysis and quite costly. This paper presents the application of in-house developed Electronic Nose (e-nose) to classify new aromatic rice varieties. The e-nose is used to classify the variety of aromatic rice based on the samples odour. The samples were taken from the variety of rice. The instrument utilizes multivariate statistical data analysis, including Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and K-Nearest Neighbours (KNN) to classify the unknown rice samples. The Leave-One-Out (LOO) validation approach is applied to evaluate the ability of KNN to perform recognition and classification of the unspecified samples. The visual observation of the PCA and LDA plots of the rice proves that the instrument was able to separate the samples into different clusters accordingly. The results of LDA and KNN with low misclassification error support the above findings and we may conclude that the e-nose is successfully applied to the classification of the aromatic rice varieties.

  15. Polycyclic aromatic hydrocarbons in air samples of meat smokehouses

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Olsen, I L; Poulsen, O M

    1992-01-01

    In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors or approx......In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors...

  16. Unleaded gasoline with reduction in benzene and aromatics

    International Nuclear Information System (INIS)

    Ahmed, I.

    2003-01-01

    The trend today is towards making gasoline more environment and human friendly or in other words making gasoline a really clean fuel. This paper covers the ill effects of benzene and aromatics and the driving force behind their reduction in gasoline worldwide. It addresses health concerns specifically, and the theme is unleaded gasoline without simultaneously addressing reduction in benzene and aromatics is more harmful. The paper cites worldwide case studies, and also the World Bank (WB), Government of Pakistan (GoP), and United Nations (UN) efforts in this area in Pakistan. (author)

  17. New insights into the formation of fungal aromatic polyketides.

    Science.gov (United States)

    Crawford, Jason M; Townsend, Craig A

    2010-12-01

    Fungal aromatic polyketides constitute a large family of bioactive natural products and are synthesized by the non-reducing group of iterative polyketide synthases (PKSs). Their diverse structures arise from selective enzymatic modifications of reactive, enzyme-bound poly-β-keto intermediates. How iterative PKSs control starter unit selection, polyketide chain initiation and elongation, intermediate folding and cyclization, selective redox or modification reactions during assembly, and product release are central mechanistic questions underlying iterative catalysis. This Review highlights recent insights into these questions, with a particular focus on the biosynthetic programming of fungal aromatic polyketides, and draws comparisons with the allied biosynthetic processes in bacteria.

  18. Interaction of aromatic molecules with small gold clusters

    Science.gov (United States)

    Molina, Luis M.; López, María. J.; Alonso, Julio A.

    2017-09-01

    Ab initio density functional simulations have been performed to study the adsorption of aromatic molecules (benzene and toluene) on small Aun clusters. The calculations reveal a strong interaction between gold and π electrons of benzene, accompanied by a small electronic charge transfer from benzene to gold. We report a variety of binding conformations, with varying degrees of contact between the carbon atoms in benzene and the cluster. Therefore, the interaction between the aromatic part of molecules involved in the synthesis of fine chemicals catalyzed by gold must not be neglected, and could play an important role during some reaction stages.

  19. Monitoring the biodegradation of polycyclic aromatic hydrocarbons in a co-contaminated soil using stable isotope labeling

    Science.gov (United States)

    Wawra, Anna; Friesl-Hanl, Wolfgang; Watzinger, Andrea; Soja, Gerhard; Puschenreiter, Markus

    2016-04-01

    Conventional remediation techniques like "dig and dump" are costly and limited in scale. Plant- and microbe-based alternatives, e.g. phytoremediation options, offer a cheap and environmentally friendly approach that can be applied on larger areas. However, the application of phytoremediation techniques to co-contaminated sites may be hindered due to a potential inhibition of biodegradation processes by the presence of heavy metals in soil. Therefore, the objective of this study is to test the hypothesis that the degradation of organic pollutants can be enhanced by immobilising potentially toxic heavy metals. This study aims to identify the influence of heavy metal immobilisation on the degradation of organic pollutants, and to determine chemical, physical and biological measures further accelerating these processes. The influence of heavy metals on organic pollutant degradation dynamics is assessed using 13C-phospholipid fatty acid analysis (13C-PLFA). Application of 13C-labeled phenanthrene allows the identification of microbial groups responsible for the degradation process. For metal immobilisation and enhanced biodegradation, distinct mineral and organic soil amendments (iron oxides, gravel sludge, biochar) are deployed, partly in combination with fast-growing and pollution-tolerant woody plants (willow, black locust and alder). Results of an incubation batch experiment show a fast degradation of the phenanthrene label within the first two weeks by various microbial groups (gram negative bacteria as indicated by the cy17:0 peak) resulting in a decrease by up to 80% of the total PAH concentration (Σ 16 EPA PAHs) measured in soil. A similar trend was observed in the greenhouse pot experiment, whereby heavy metal accumulation in the woody plants growing on the co-contaminated soil significantly varied with plant species (willow > black locust, alder).

  20. Stable Hemiaminals: 2-Aminopyrimidine Derivatives

    Directory of Open Access Journals (Sweden)

    Anna Kwiecień

    2015-08-01

    Full Text Available Stable hemiaminals can be obtained in the one-pot reaction between 2-aminopyrimidine and nitrobenzaldehyde derivatives. Ten new hemiaminals have been obtained, six of them in crystal state. The molecular stability of these intermediates results from the presence of both electron-withdrawing nitro groups as substituents on the phenyl ring and pyrimidine ring, so no further stabilisation by intramolecular interaction is required. Hemiaminal molecules possess a tetrahedral carbon atom constituting a stereogenic centre. As the result of crystallisation in centrosymmetric space groups both enantiomers are present in the crystal structure.

  1. Organic synthesis with stable isotopes

    International Nuclear Information System (INIS)

    Daub, G.H.; Kerr, V.N.; Williams, D.L.; Whaley, T.W.

    1978-01-01

    Some general considerations concerning organic synthesis with stable isotopes are presented. Illustrative examples are described and discussed. The examples include DL-2-amino-3-methyl- 13 C-butanoic-3,4- 13 C 2 acid (DL-valine- 13 C 3 ); methyl oleate-1- 13 C; thymine-2,6- 13 C 2 ; 2-aminoethanesulfonic- 13 C acid (taurine- 13 C); D-glucose-6- 13 C; DL-2-amino-3-methylpentanoic-3,4- 13 C 2 acid (DL-isoleucine- 13 C 2 ); benzidine- 15 N 2 ; and 4-ethylsulfonyl-1-naphthalene-sulfonamide- 15 N

  2. Stable agents for imaging investigations

    International Nuclear Information System (INIS)

    Tofe, A.J.

    1976-01-01

    This invention concerns highly stable compounds useful in preparing technetium 99m based scintiscanning exploration agents. The compounds of this invention include a pertechnetate reducing agent or a solution of oxidized pertechnetate and an efficient proportion, sufficient to stabilize the compounds in the presence of oxygen and of radiolysis products, of ascorbic acid or a pharmaceutically acceptable salt or ester of this acid. The invention also concerns a perfected process for preparing a technetium based exploration agent, consisting in codissolving the ascorbic acid or a pharmaceutically acceptable salt or ester of such an acid and a pertechnetate reducing agent in a solution of oxidized pertechnetate [fr

  3. Stable cosmology in chameleon bigravity

    Science.gov (United States)

    De Felice, Antonio; Mukohyama, Shinji; Oliosi, Michele; Watanabe, Yota

    2018-02-01

    The recently proposed chameleonic extension of bigravity theory, by including a scalar field dependence in the graviton potential, avoids several fine-tunings found to be necessary in usual massive bigravity. In particular it ensures that the Higuchi bound is satisfied at all scales, that no Vainshtein mechanism is needed to satisfy Solar System experiments, and that the strong coupling scale is always above the scale of cosmological interest all the way up to the early Universe. This paper extends the previous work by presenting a stable example of cosmology in the chameleon bigravity model. We find a set of initial conditions and parameters such that the derived stability conditions on general flat Friedmann background are satisfied at all times. The evolution goes through radiation-dominated, matter-dominated, and de Sitter eras. We argue that the parameter space allowing for such a stable evolution may be large enough to encompass an observationally viable evolution. We also argue that our model satisfies all known constraints due to gravitational wave observations so far and thus can be considered as a unique testing ground of gravitational wave phenomenologies in bimetric theories of gravity.

  4. Stable isotope analyses - an innovative technique to monitor biodegradation of petroleum hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, C. A.; Coffin, R. B.; Mueller, J. G.

    1998-09-01

    Results of studies to examine variations in stable isotope ratios of compounds upon degradation and transport through soil and ground water are discussed. These studies were undertaken as part of a study on the usefulness of stable carbon isotopes in bioremediation programs. The assumption was that stable isotope values can be used to fingerprint contaminant sources by measuring the stable isotope values of polycyclic aromatic hydrocarbons (PAHs) extracted from soil slurries with and without the occurrence of bacterial degradation. Creosote-contaminated soil samples were obtained from a respirometry study in Pensacola, Florida. Liquid-liquid extraction methods were used to extract PAHs from the groundwater. The PAH-containing organic phase was separated from the aqueous phase, dried with anhydrous sodium sulfate and concentrated. Concentration was determined by gas chromatography using external standard curve. Results showed that only four PAH compounds (acenapthene, fluorene, phenanthrene, and fluoranthene) had high enough concentrations to measure the {delta}{sup 1}3 C values for both the killed bacterial cell control (no degradation) and the degraded sample. Of these four, phenanthrene was the most degraded (69 per cent removed after seven days) and fluoranthene was the least degraded (25 per cent removed). The isotopic composition of the PAHs measured along the source site dilution transect remained consistent. It appears that neither dilution nor degradation significantly altered the stable isotopic composition of these compounds. 6 refs., 5 figs.

  5. Adsorption of polar, nonpolar, and substituted aromatics to colloidal graphene oxide nanoparticles

    NARCIS (Netherlands)

    Wang, Fang; Haftka, Joris J H; Sinnige, Theo L.; Hermens, Joop L M; Chen, Wei

    2014-01-01

    We conducted batch adsorption experiments to understand the adsorptive properties of colloidal graphene oxide nanoparticles (GONPs) for a range of environmentally relevant aromatics and substituted aromatics, including model nonpolar compounds (pyrene, phenanthrene, naphthalene, and

  6. Applications of electrochemically-modulated liquid chromatography (EMLC): Separations of aromatic amino acids and polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Li [Iowa State Univ., Ames, IA (United States)

    1998-03-27

    The research in this thesis explores the separation capabilities of a new technique termed electrochemically-modulated liquid chromatography (EMLC). The thesis begins with a general introduction section which provides a literature review of this technique as well as a brief background discussion of the two research projects in each of the next two chapters. The two papers which follow investigate the application of EMLC to the separation of a mixture of aromatic amino acids and of a mixture of polycyclic aromatic hydrocarbons (PAHs). The last section presents general conclusions and summarizes the thesis. References are compiled in the reference section of each chapter. The two papers have been removed for separate processing.

  7. Stable isotope mass spectrometry in petroleum exploration

    International Nuclear Information System (INIS)

    Mathur, Manju

    1997-01-01

    The stable isotope mass spectrometry plays an important role to evaluate the stable isotopic composition of hydrocarbons. The isotopic ratios of certain elements in petroleum samples reflect certain characteristics which are useful for petroleum exploration

  8. Palladium-catalysed electrophilic aromatic C-H fluorination

    Science.gov (United States)

    Yamamoto, Kumiko; Li, Jiakun; Garber, Jeffrey A. O.; Rolfes, Julian D.; Boursalian, Gregory B.; Borghs, Jannik C.; Genicot, Christophe; Jacq, Jérôme; van Gastel, Maurice; Neese, Frank; Ritter, Tobias

    2018-02-01

    Aryl fluorides are widely used in the pharmaceutical and agrochemical industries, and recent advances have enabled their synthesis through the conversion of various functional groups. However, there is a lack of general methods for direct aromatic carbon-hydrogen (C-H) fluorination. Conventional methods require the use of either strong fluorinating reagents, which are often unselective and difficult to handle, such as elemental fluorine, or less reactive reagents that attack only the most activated arenes, which reduces the substrate scope. A method for the direct fluorination of aromatic C-H bonds could facilitate access to fluorinated derivatives of functional molecules that would otherwise be difficult to produce. For example, drug candidates with improved properties, such as increased metabolic stability or better blood-brain-barrier penetration, may become available. Here we describe an approach to catalysis and the resulting development of an undirected, palladium-catalysed method for aromatic C-H fluorination using mild electrophilic fluorinating reagents. The reaction involves a mode of catalysis that is unusual in aromatic C-H functionalization because no organometallic intermediate is formed; instead, a reactive transition-metal-fluoride electrophile is generated catalytically for the fluorination of arenes that do not otherwise react with mild fluorinating reagents. The scope and functional-group tolerance of this reaction could provide access to functional fluorinated molecules in pharmaceutical and agrochemical development that would otherwise not be readily accessible.

  9. A neurotoxicity assessment of high flash aromatic naphtha.

    Science.gov (United States)

    Douglas, J F; McKee, R H; Cagen, S Z; Schmitt, S L; Beatty, P W; Swanson, M S; Schreiner, C A; Ulrich, C E; Cockrell, B Y

    1993-01-01

    Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide-boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 Aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent also known as High Flash Aromatic Naphtha (HFAN). A program was initiated to assess the toxicological properties of HFAN since there may be human exposure, especially in the workplace. The current study was conducted to assess the potential for neurotoxicity in the rat. Adult male Sprague-Dawley rats of approximately 300 grams body weight, in groups of twenty, were exposed by inhalation to HFAN for 90 days at concentrations of 0, 100, 500, and 1500 ppm. During this period the animals were tested monthly for motor activity and in a functional observation battery. After three months of exposure, for 6 hours/day, 5 days/week, 10 animals/group/sex were sacrificed and selected nervous system tissue was examined histopathologically. No signs of neurotoxicity were seen in any of the evaluated parameters, nor was there evidence of pathologic changes in any of the examined tissues.

  10. Mycotoxicogenic fungal inhibition by innovative cheese cover with aromatic plants.

    Science.gov (United States)

    Moro, Armando; Librán, Celia M; Berruga, M Isabel; Zalacain, Amaya; Carmona, Manuel

    2013-03-30

    The use of aromatic plants and their extracts with antimicrobial properties may be compromised in the case of cheese, as some type of fungal starter is needed during its production. Penicillium verrucosum is considered a common cheese spoiler. The aim of this study was to evaluate the innovative use of certain aromatic plants as natural cheese covers in order to prevent mycotoxicogenic fungal growth (P. verrucosum). A collection of 12 essential oils (EOs) was obtained from various aromatic plants by solvent-free microwave extraction technology, and volatile characterisation of the EOs was carried out by gas chromatography/mass spectrometry. The most effective EOs against P. verrucosum were obtained from Anethum graveolens, Hyssopus officinalis and Chamaemelum nobile, yielding 50% inhibition of fungal growth at concentration values lower than 0.02 µL mL⁻¹. All EOs showed high volatile heterogeneity, with α-phellandrene, pinocamphone, isopinocamphone, α-pinene, camphene, 1,8-cineole, carvacrol and trans-anethole being found to be statistically significant in the antifungal model. The use of these aromatic plants as natural covers on cheese can satisfactorily inhibit the growth of some mycotoxicogenic fungal spoilers. Among the volatile compounds present, α- and β-phellandrene were confirmed as the most relevant in the inhibition. © 2012 Society of Chemical Industry.

  11. The aromatic and polyphenolic composition of Roman camomile tea.

    Science.gov (United States)

    Carnat, A; Carnat, A P; Fraisse, D; Ricoux, L; Lamaison, J L

    2004-01-01

    The qualitative and quantitative composition of the main aromatic and polyphenolic constituents of infusion from Chamaemelum nobile flowers was examined. The camomile tea contained a large amount of polyphenolic compounds (340 mg/l), the most important being chamaemeloside (155 mg/l). Only traces of essential oil were recovered in tea (7 mg/l).

  12. Polycyclic Aromatic Hydrocarbons (PAHs) and some Trace metals in ...

    African Journals Online (AJOL)

    Polycyclic Aromatic Hydrocarbons (PAHs) and some Trace metals in Yam, Cassava, Orange and Papaya from two Oil and Gas Flaring Impacted Communities in Southern Nigeria. ... metals in response to contamination. Keywords: PAHs levels; Hydrocarbon contaminant exposure; Food safety; Fruits and tubers.

  13. Polycyclic aromatic hydrocarbons in municipal waste ashes from ...

    African Journals Online (AJOL)

    The levels of isolated polycyclic aromatic hydrocarbons (PAH) in ash residues of wastes from some major waste dumps in Lagos, Nigeria, were determined. The total amounts of the PAH in the ashes were in the range of 0.06 – 0.4 mg/g. The ash from the waste dump that contains the highest level also displayed greatest ...

  14. Metal mediated amination of aromatic rings following carbon ...

    Indian Academy of Sciences (India)

    Administrator

    Metal-mediated reactions which result in addition of [NR]2– fragments belong to a reaction class of fundamental importance in chemistry in connection with carbon- nitrogen bond formation processes. In this presentation we wish to report our results on aromatic ring amination of a pendant phenyl ring of coordinated ...

  15. Source apportionment of polycyclic aromatic hydrocarbon in soil ...

    African Journals Online (AJOL)

    The13C/12C isotopic ratios of polycyclic aromatic hydrocarbons (PHCs) for soil samples collected and preserved from contact with any other source(s) of PAHs except atmospheric, between the years 1865 and 1986 in the United Kingdom, were determined, in order to understand PAHs source apportionment within the ...

  16. Inclusion of poly-aromatic hydrocarbon (PAH) molecules in a ...

    Indian Academy of Sciences (India)

    The internal surface of an Mg-Al layered double hydroxide has been functionalized by anchoring carboxy-methyl derivatized -cyclodextrin cavities to the gallery walls. Neutral polyaromatic hydrocarbon (PAH) molecules have been included within the functionalized solid by driving the hydrophobic aromatic molecules from ...

  17. Source determination of polynuclear aromatic hydrocarbons in water ...

    African Journals Online (AJOL)

    SERVER

    2008-02-05

    Feb 5, 2008 ... Polynuclear aromatic hydrocarbons in surface water and sediment of Ekpan Creek of the Warri River were determined with GC Perkin-Elmer/Clarius 500. Compositional patterns of the PAHs were used to distinguish their sources in the aquatic system. The three diagnostic selected concentration ratios of.

  18. Effect of Smoking on Polycyclic Aromatic Hydrocarbons (PAHS ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Department of Chemistry, Michael Okpara University of Agriculture, Umudike,. P.M.B 7267, Umuahia, Abia State, Nigeria. ABSTRACT: The effects of smoking on proximate composition, energy values and concentrations of polycyclic aromatic hydrocarbons (PAHs) were studied in raw and smoked samples of catfish (Clarias ...

  19. Biodegradation of Polycyclic Aromatic Hydrocarbons in Crude oil ...

    African Journals Online (AJOL)

    ADOWIE PERE

    ABSTRACT: Release of crude oil and its products into the environment has resulted in many problems that are of global concern. The objective of this study was to determine effect of Composted Market Waste (CMW) on the degradation of Polycyclic Aromatic Hydrocarbons (PAHs) in crude oil-contaminated soil.

  20. A STUDY OF THE MICROBIOLOGY AND POLYCYCLIC AROMATIC ...

    African Journals Online (AJOL)

    muds (Okparanma et al., 2010). This study therefore aimed at assessing the environmental effects of drill cuttings generated from Ologbo oilfield wells with respect to their microbiological characteristics and the poly cyclic aromatic hydrocarbons compositional profile and their possible sources. MATERIALS AND METHODS.

  1. Metal mediated amination of aromatic rings following carbon ...

    Indian Academy of Sciences (India)

    Administrator

    Metal mediated amination of aromatic rings following carbon-nitrogen bond formation and the coordination chemistry thereof. AMRITA SAHA, AMIT K GHOSH, PARTHA MAJUMDAR and. SREEBRATA GOSWAMI. Department of Inorganic Chemistry, Indian Association for the Cultivation of. Science, Calcutta 700 032, India.

  2. Determination of levels of polycyclic aromatic hydrocarbons in soil ...

    African Journals Online (AJOL)

    Soil samples contaminated with spent motor engine oil collected from Abakaliki auto-mechanic site were analyzed to determine the concentration of polycyclic aromatic hydrocarbon (PAH) components which are often targets in environmental check. Identification and quantification of the PAH components was accomplished ...

  3. Genetics Home Reference: aromatic l-amino acid decarboxylase deficiency

    Science.gov (United States)

    ... and treatment of a new inborn error of neurotransmitter amine synthesis. Neurology. 1992 Oct;42(10):1980-8. Citation on PubMed Hyland K. Inherited disorders affecting dopamine and serotonin: critical neurotransmitters derived from aromatic amino acids. J Nutr. 2007 ...

  4. Interactions of polyhalogenated aromatic hydrocarbons with thyroid hormone metabolism

    NARCIS (Netherlands)

    Schuur, A.G.

    1998-01-01

    This thesis deals with the possible interactions of polyhalogenated aromatic hydrocarbons and/or their metabolites with thyroid hormone metabolism. This chapter summarizes firstly the effects of thyroid hormone on the induction of biotransformation enzymes by PHAHs. Secondly, the results on

  5. Continuous group and electron-count rules in aromaticity

    Indian Academy of Sciences (India)

    Pradeep Kumar

    2018-02-07

    Feb 7, 2018 ... In the present article a group theoretical approach has been used to explain different electron-count rules for aromaticity. A general group theoretical method is presented to derive and unite the different electron count rules (Hückel, Baird, ... benzene, researchers tried to explain it on the basis of spherical ...

  6. Sodium borohydride reduction of aromatic carboxylic acids via ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. A number of important aromatic carboxylic acids precursors, or intermediates in the syntheses of natural products, are converted into methyl esters and reduced to the corresponding primary alcohols using a sodium borohydride–THF–methanol system. The alcohols are obtained in 70–92% yields in 2–. 5 hours, in ...

  7. Effects of selected multipurpose, medicinal and aromatic plants on in ...

    African Journals Online (AJOL)

    The study was carried out to evaluate the effects of selected multipurpose, medicinal and aromatic plants on the in vitro methane production and microbial diversity. The plants include multi-purpose trees; Pterocarpus santallinoides, Leucaena leucocephala, Albizia lebbek, Albizia saman, Enterolobium cyclocarpum, ...

  8. Biodegradation of polycyclic aromatic hydrocarbons (PAHs) by white ...

    African Journals Online (AJOL)

    ... activity, and Pseudotrametes gibbosa had significant potential due to its higher laccase production and more potent degradation of PAHs. This study provides technical support for pollution amelioration using aboriginal white-rot fungus. Key words: White-rot fungus, laccase, polycyclic aromatic hydrocarbons, degradation.

  9. Thiacalix[4]arene derivatives containing multiple aromatic groups ...

    Indian Academy of Sciences (India)

    novel thiacalix[4]arene derivatives containing multiple aromatic groups in yields of 86% and 90%. Their com- plexation properties for four organic dyes were investigated by liquid-liquid extraction experiments, complex- ation UV-Vis spectra and mass spectrum. The highest extraction percentage was 97% for Neutral red.

  10. Extraction of polycyclic aromatic nitrogen heterocycles from spiked soil samples

    Czech Academy of Sciences Publication Activity Database

    Kočí, K.; Petrovská, H.; Šimek, Z.; Varaďová-Ostrá, Elena; Syslová, A.

    2007-01-01

    Roč. 87, č. 2 (2007), s. 111-123 ISSN 0306-7319 Institutional research plan: CEZ:AV0Z40310501 Keywords : polycyclic aromatic nitrogen heterocycle * supercritical fluid extraction * Soxhlet Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.026, year: 2007

  11. Aromatic nitrations by mixed acid. Fast liquid-liquid regime

    NARCIS (Netherlands)

    Zaldivar, J.M.; Zaldivar, J.M.; Molga, E.J.; Alos, M.A.; Hernandez, H.; Westerterp, K.R.

    1996-01-01

    Aromatic nitration by mixed acid was selected as a specific case of heterogeneous liquid-liquid reaction. An extensive experimental programme was followed using adiabatic and heat flow calorimetry and pilot reactor experiments, supported by chemical analysis. A series of nitration experiments was

  12. A study of the microbiology and polycyclic aromatic hydrocarbons ...

    African Journals Online (AJOL)

    A study was carried out on the drill cuttings from three different oil and gas wells located at Ologbo Community at Edo State with respect to their microbiology and polycyclic aromatic hydrocarbons (PAHs) compositional profile and sources. Isolation and enumeration of heterotrophic bacteria and fungi was carried out using ...

  13. Effect of smoking on Polycyclic Aromatic Hydrocarbons (PAHS ...

    African Journals Online (AJOL)

    The effects of smoking on proximate composition, energy values and concentrations of polycyclic aromatic hydrocarbons (PAHs) were studied in raw and smoked samples of catfish (Clarias gariepinus) and tilapia (Oreochromis niloticus). Crude protein was higher in the tilapia sample for both raw and smoked samples.

  14. Regioselective nitration of aromatic substrates in zeolite cages

    Indian Academy of Sciences (India)

    Unknown

    meet market demand, Choudary et al have achieved a zeolite-based methodology for the nitration of aromatic compounds.13 They have carried out nitration of toluene with various zeolite catalysts and zeolite beta of different Si/Al ratios. Zeolite beta has proved to be the best catalyst among the zeolites used in terms of ...

  15. Reaction of benzoxasilocines with aromatic aldehydes: Synthesis of homopterocarpans

    Directory of Open Access Journals (Sweden)

    Rodríguez-García Ignacio

    2007-02-01

    Full Text Available Abstract Condensation of 2H-benzo[g][1,2]oxasilocines with aromatic aldehydes in the presence of boron trifluoride affords mixtures of cis/trans 2-phenyl-3-vinylchromans with moderate yields. These can be transformed into homopterocarpans, a synthetic group of substances homologous to the natural isoflavonoid pterocarpans.

  16. Polycyclic aromatic hydrocarbons (PAH) in Danish barbecued meat

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Aaslyng, Margit Dall; Meinert, Lene

    2015-01-01

    Barbecuing is known to result in the formation of polycyclic aromatic hydrocarbons (PAHs). A validated method that employed pressurized liquid extraction (PLE), gel permeation chromatography (GPC) followed by solid phase extraction (SPE) on Silica and analytical determination by GC-MS was applied...

  17. Thiacalix[4]arene derivatives containing multiple aromatic groups ...

    Indian Academy of Sciences (India)

    plexation properties for four organic dyes were investigated by liquid-liquid extraction experiments, complex- ation UV-Vis spectra and mass spectrum. The highest extraction percentage was 97% for Neutral red. The UV-. Vis spectra and .... tiple aromatic groups were synthesized after simple recrystallization. The yields of ...

  18. Microbial Degradation of Polycyclic Aromatic Hydrocarbons and Characterization of Bacteria

    Science.gov (United States)

    Tikilili, P. V.; Chirwa, E. M. N.

    2010-01-01

    Biodegradation of polycyclic aromatic hydrocarbons was studied. Naphthalene was used as a model compound to represent these compounds. Low initial concentrations of naphthalene in a range of 30-60 mg/L were completely degraded after incubation for 15 hrs by consortia from a landfill soil while consortia from minewater took more that 29 hrs to reach complete degradation.

  19. Enhancement of aromatic and saturated hydrocarbon by modified ...

    African Journals Online (AJOL)

    Three sediment samples collected from the Qua Iboe River System and eighteen different column packing ratios of silica gel and alumina were used in this investigation. The variation of the composition of the stationary phase (silica gel and alumina, SA) gave different yields of aromatic and saturated hydrocarbons. In all the ...

  20. Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas.

    Science.gov (United States)

    Nwinyi, Obinna C; Ajayi, Oluseyi O; Amund, Olukayode O

    2016-01-01

    The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbons degraders that can utilize polynuclear aromatic hydrocarbons of former industrial sites at McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment method based on soil slurry, we isolated, screened and purified two bacterial species strains PB1 and PB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains were assigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonas sp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agar plates during the preliminary investigations. Using time course studies in the liquid cultures at calculated concentrations 123, 64, 97 and 94ppm for naphthalene, chrysene, fluroanthene and pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilization of the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and 40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developed a model R(2)=1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, we confirm that the former industrial site soil microbial communities may be explored for the biorestoration of the industrial site. Copyright © 2016. Published by Elsevier Editora Ltda.

  1. Does alkali cation binding to aromatic ring retard the fluxional ...

    Indian Academy of Sciences (India)

    A Kalpana

    2017-11-10

    Nov 10, 2017 ... the role of cation on haptotropic migration. Cation binding not only enhances the complex interaction energy but also delicately affects the fluxionality in the molecule by increasing the barrier to haptotropic shift of Cr(CO)3. The competing nature of the bifacial acids with sandwiched aromatic ring is ...

  2. carcinogenic potency of polycyclic aromatic hydrocarbons in soil

    African Journals Online (AJOL)

    Carcinogenic potency of polycyclic aromatic hydrocarbons (PAHs) in soils obtained from seven different sampling locations in Effurun metropolis and its environs of Niger Delta Area of Nigeria were evaluated. The 16 US EPA priority PAHs were determined with GC-MS. The concentrations of individual PAHs observed were ...

  3. An Evaluation of Polycyclic Aromatic Hydrocarbons in Hemichromis ...

    African Journals Online (AJOL)

    The concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) were analysed in Hemichromis fasciatus netted from the Ikpoba reservoir in Benin City, Nigeria, using Gas chromatographic technique, in order to evaluate the potential ecological risk of these organic pollutants on the investigated ecosystem. The mean ...

  4. Biodegradation of polycyclic aromatic hydrocarbons in crude oil ...

    African Journals Online (AJOL)

    Release of crude oil and its products into the environment has resulted in many problems that are of global concern. The objective of this study was to determine effect of Composted Market Waste (CMW) on the degradation of Polycyclic Aromatic Hydrocarbons (PAHs) in crude oil-contaminated soil. Pot experiment was ...

  5. Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in a tropical ...

    African Journals Online (AJOL)

    The distribution of 8 polycyclic aromatic hydrocarbons (PAHs) in the surface sediments of the Grand-Lahou lagoon (Côte d'Ivoire) was investigated using a high performance liquid chromatography (HPLC). The total concentrations of PAHs were between 1.55 and 437.52 μg/g in the dry season. Pyrene, benzo (b) ...

  6. Polycyclic Aromatic Hydrocarbons in Air and their Toxic Potency

    Indian Academy of Sciences (India)

    GENERAL I ARTICLE. Polycyclic Aromatic Hydrocarbons in Air and their Toxic Potency. R Mohanraj is currently working as Senior Research. Fellow in Environmental. Impact Assessment (EIA). Division of Salim Ali Centre for Ornithology and Natural. History (SACON),. Coimbatore. His primary interest lies in aerosol.

  7. Polycyclic aromatic hydrocarbons in occupational vs. urban environmental air

    NARCIS (Netherlands)

    Branisteanu, R.; Aiking, H.

    1998-01-01

    Objectives: To evaluate the balance between occupational and environmental exposure to suspended particulate matter (SPM) and polycyclic aromatic hydrocarbons (PAHs), comparison measurements were performed in a coal-fired power plant and the urban atmosphere from the town nearby. Methods: The

  8. Stable rotating dipole solitons in nonlocal media

    DEFF Research Database (Denmark)

    Lopez-Aguayo, Servando; Skupin, Stefan; Desyatnikov, Anton S.

    2006-01-01

    We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons.......We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons....

  9. A Facile Solid-Phase Route to Renewable Aromatic Chemicals from Biobased Furanics

    NARCIS (Netherlands)

    Thiyagarajan, Shanmugam; Genuino, H.C.; Waal, van der J.C.; Jong, de Ed; Weckhuysen, B.M.; Haveren, van Jacco; Bruijnincx, P.C.A.; Es, van D.S.

    2016-01-01

    Renewable aromatics can be conveniently synthesized from furanics by introducing an intermediate hydrogenation step in the Diels-Alder (DA) aromatization route, to effectively block retro-DA activity. Aromatization of the hydrogenated DA adducts requires tandem catalysis, using a metal-based

  10. Himalayan Aromatic Medicinal Plants: A Review of their Ethnopharmacology, Volatile Phytochemistry, and Biological Activities.

    Science.gov (United States)

    Joshi, Rakesh K; Satyal, Prabodh; Setzer, Wiliam N

    2016-02-19

    Aromatic plants have played key roles in the lives of tribal peoples living in the Himalaya by providing products for both food and medicine. This review presents a summary of aromatic medicinal plants from the Indian Himalaya, Nepal, and Bhutan, focusing on plant species for which volatile compositions have been described. The review summarizes 116 aromatic plant species distributed over 26 families.

  11. Himalayan Aromatic Medicinal Plants: A Review of their Ethnopharmacology, Volatile Phytochemistry, and Biological Activities

    OpenAIRE

    Joshi, Rakesh K.; Satyal, Prabodh; Setzer, Wiliam N.

    2016-01-01

    Aromatic plants have played key roles in the lives of tribal peoples living in the Himalaya by providing products for both food and medicine. This review presents a summary of aromatic medicinal plants from the Indian Himalaya, Nepal, and Bhutan, focusing on plant species for which volatile compositions have been described. The review summarizes 116 aromatic plant species distributed over 26 families.

  12. Ambient aromatic hydrocarbon measurements at Welgegund, South Africa

    Science.gov (United States)

    Jaars, K.; Beukes, J. P.; van Zyl, P. G.; Venter, A. D.; Josipovic, M.; Pienaar, J. J.; Vakkari, V.; Aaltonen, H.; Laakso, H.; Kulmala, M.; Tiitta, P.; Guenther, A.; Hellén, H.; Laakso, L.; Hakola, H.

    2014-07-01

    Aromatic hydrocarbons are associated with direct adverse human health effects and can have negative impacts on ecosystems due to their toxicity, as well as indirect negative effects through the formation of tropospheric ozone and secondary organic aerosol, which affect human health, crop production and regional climate. Measurements of aromatic hydrocarbons were conducted at the Welgegund measurement station (South Africa), which is considered to be a regionally representative background site. However, the site is occasionally impacted by plumes from major anthropogenic source regions in the interior of South Africa, which include the western Bushveld Igneous Complex (e.g. platinum, base metal and ferrochrome smelters), the eastern Bushveld Igneous Complex (platinum and ferrochrome smelters), the Johannesburg-Pretoria metropolitan conurbation (> 10 million people), the Vaal Triangle (e.g. petrochemical and pyrometallurgical industries), the Mpumalanga Highveld (e.g. coal-fired power plants and petrochemical industry) and also a region of anticyclonic recirculation of air mass over the interior of South Africa. The aromatic hydrocarbon measurements were conducted with an automated sampler on Tenax-TA and Carbopack-B adsorbent tubes with heated inlet for 1 year. Samples were collected twice a week for 2 h during daytime and 2 h during night-time. A thermal desorption unit, connected to a gas chromatograph and a mass selective detector was used for sample preparation and analysis. Results indicated that the monthly median (mean) total aromatic hydrocarbon concentrations ranged between 0.01 (0.011) and 3.1 (3.2) ppb. Benzene levels did not exceed the local air quality standard limit, i.e. annual mean of 1.6 ppb. Toluene was the most abundant compound, with an annual median (mean) concentration of 0.63 (0.89) ppb. No statistically significant differences in the concentrations measured during daytime and night-time were found, and no distinct seasonal patterns were

  13. Uses of stable isotopes in fish ecology

    Science.gov (United States)

    Analyses of fish tissues (other than otoliths) for stable isotope ratios can provide substantial information on fish ecology, including physiological ecology. Stable isotopes of nitrogen and carbon frequently are used to determine the mix of diet sources for consumers. Stable i...

  14. Periodicity of the stable isotopes

    CERN Document Server

    Boeyens, J C A

    2003-01-01

    It is demonstrated that all stable (non-radioactive) isotopes are formally interrelated as the products of systematically adding alpha particles to four elementary units. The region of stability against radioactive decay is shown to obey a general trend based on number theory and contains the periodic law of the elements as a special case. This general law restricts the number of what may be considered as natural elements to 100 and is based on a proton:neutron ratio that matches the golden ratio, characteristic of biological and crystal growth structures. Different forms of the periodic table inferred at other proton:neutron ratios indicate that the electronic configuration of atoms is variable and may be a function of environmental pressure. Cosmic consequences of this postulate are examined. (author)

  15. Stable States of Biological Organisms

    Science.gov (United States)

    Yukalov, V. I.; Sornette, D.; Yukalova, E. P.; Henry, J.-Y.; Cobb, J. P.

    2009-04-01

    A novel model of biological organisms is advanced, treating an organism as a self-consistent system subject to a pathogen flux. The principal novelty of the model is that it describes not some parts, but a biological organism as a whole. The organism is modeled by a five-dimensional dynamical system. The organism homeostasis is described by the evolution equations for five interacting components: healthy cells, ill cells, innate immune cells, specific immune cells, and pathogens. The stability analysis demonstrates that, in a wide domain of the parameter space, the system exhibits robust structural stability. There always exist four stable stationary solutions characterizing four qualitatively differing states of the organism: alive state, boundary state, critical state, and dead state.

  16. Theory of stable allocations II

    Directory of Open Access Journals (Sweden)

    Pantelić Svetlana

    2015-01-01

    Full Text Available The Swedish Royal Academy awarded the 2012 Nobel Prize in Economics to Lloyd Shapley and Alvin Roth, for the theory of stable allocations and the practice of market design. These two American researchers worked independently from each other, combining basic theory and empirical investigations. Through their experiments and practical design they generated a flourishing field of research and improved the performance of many markets. Shapley provided the fundamental theoretical contribution to this field of research, whereas Roth, a professor at the Harvard University in Boston, developed and upgraded these theoretical investigations by applying them to the American market of medical doctors. Namely, their research helps explain the market processes at work, for instance, when doctors are assigned to hospitals, students to schools and human organs for transplant to recipients.

  17. Stable massive particles at colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fairbairn, M.; /Stockholm U.; Kraan, A.C.; /Pennsylvania U.; Milstead, D.A.; /Stockholm U.; Sjostrand, T.; /Lund U.; Skands, P.; /Fermilab; Sloan, T.; /Lancaster U.

    2006-11-01

    We review the theoretical motivations and experimental status of searches for stable massive particles (SMPs) which could be sufficiently long-lived as to be directly detected at collider experiments. The discovery of such particles would address a number of important questions in modern physics including the origin and composition of dark matter in the universe and the unification of the fundamental forces. This review describes the techniques used in SMP-searches at collider experiments and the limits so far obtained on the production of SMPs which possess various colour, electric and magnetic charge quantum numbers. We also describe theoretical scenarios which predict SMPs, the phenomenology needed to model their production at colliders and interactions with matter. In addition, the interplay between collider searches and open questions in cosmology such as dark matter composition are addressed.

  18. Isotopic criteria in the characterization of aromatic molecules. 2. Influence of the chemical elaboration process.

    Science.gov (United States)

    Martin, Gerard J; Heck, Georg; Djamaris-Zainal, Risnayeti; Martin, Maryvonne L

    2006-12-27

    Most valued natural aromatic molecules can be substituted by their low-cost chemical counterparts. Isotopic methods, which offer the most powerful tool to infer the origin of a molecule, are applied to the characterization of a large number of chemical aromatic species. Isotopic affiliation between precursors and products is investigated in several types of reactions: oxidation of benzyl chloride and benzyl alcohol and hydrolysis of benzylidene chloride and cinnamaldehyde. The isotopic parameters strongly depend not only on the type of process but, for a given process, on the experimental conditions of the reaction. Kinetic isotope effects occurring in several formylation reactions are estimated. It is shown that, in the drastic experimental conditions of many industrial processes, the benzenic hydrogen atoms may be affected by exchange phenomena. Consequently, the site-specific isotopic parameters of the ring fragment of chemical species are usually much less stable than those of the corresponding natural molecules biosynthesized in mild environments. The isotope ratios of substituents such as CH3, CH2Cl, and CHO are more resistant to exchange and provide useful criteria for characterizing both the raw materials and the process. It is shown in particular that radical hydrogen abstraction in toluene to produce benzyl chloride induces relatively moderate fractionation effects. In contrast, oxidation reactions frequently produce strong fractionation effects. In particular, industrial direct oxidation of toluene into benzaldehyde is characterized by deuterium enrichments at the formyl site, which may exceed 900 ppm. Taking into account the large magnitude and high variability of many fractionation effects occurring in chemical reactions, the isotopic fingerprint may provide unambiguous criteria, not only for excluding a natural origin and characterizing the type of process, but also for differentiating molecules synthesized by a given process in different industrial

  19. STUDY OF FACTORS AFFECTING DEVELOPMENT OF FOOD AROMATIZATION

    Directory of Open Access Journals (Sweden)

    Н.Ye. Dubova

    2017-10-01

    Full Text Available The specific understanding of food philosophy according to the facts of development of cooking technologies and growth rate of food range is given. As it has been proven by historical stages of production of flavorings, aroma is one of the important organoleptic ingredients for food developers. A review of food production based on development of nanotechnologies, as well as promising and cautioning publications on nanotechnologies in the food sector is presented. On the basis of the literary analysis, the future impact of nanotechnologies on the evolution of the aromatization process of food products is predicted. It has been determined that the peculiarity of the development mentioned above lies in the use of plant enzymes and / or flavor precursors in the nanoscale range. The example of enzymatic breakdown of polyunsaturated fatty acids of plant cell membranes as one of the ways of creating fresh flavor of many fruits, namely C6-C9 aldehydes and alcohols, is considered. It is noted that green fresh aromatic ingredients are needed to improve the organoleptic profile of foods from heat-treated vegetables, melons and gourds. The following factors affecting the development of food aromatization are defined: the decreased differentiation of principles of healthy nutrition and fast food, repetition of natural processes of aroma formation, application of wild green leafy vegetables, and evolution of medical nutrition. The information on food aromatization by packing with autonomous mixing and their approximate assortment is given. The innovations in food aromatization are aimed at quality nutrition, time saving, recreation and entertainment, meeting specific needs (vegetarian dishes, restrictive diets.

  20. Volatilisation of aromatic hydrocarbons from coal-tar contaminated soil

    International Nuclear Information System (INIS)

    Lindhardt, B.

    1994-09-01

    A study of the non-steady-state volatilisation of organic compounds from coal tar contaminated soil. The observed fluxes from the laboratory experiments were compared with the fluxes predicted by a diffusion model assuming that the behaviour of the compounds was ideal. The diffusive release from unsaturated soil was measured in the laboratory from soil samples originating from a former gasworks site, as well as from soils spiked in the laboratory with a single model compound. The volatilisation from the surface of coal-tar contaminated soil was measured from four samples of sandy soils originating from the same site. The flux was quantified for eleven selected aromatic hydrocarbons. Volatilisation was measured from similar coal tar contaminated soil samples located below a 5 cm layer of uncontaminated and biologically inhibited soil with a an organic carbon content of 1.1% or 0.11%.monocyclic aromatic compounds. The study showed that the flux of volatile aromatic hydrocarbons,the monocyclic and the 2-ringed polycyclic aromatic hydrocarbons from coal tar contaminated soil can be estimated within one order of magnitude by a model concept which assumes that the diffusion of the compounds is independent of each other and the change in the composition of the coal tar during the experimental period can be ignored. ignored. It requires that the distribution coefficients between the coal tar contaminated soil and water are known. Where the contaminated soil resides below uncontaminated soil, degradation of the aromatic hydrocarbons can be expected if the cover layer is aerobic. The degradation will reduce the flux significantly after a period of adaption. (AB)

  1. Removal of aromatic nitro compounds from water by ozonation

    International Nuclear Information System (INIS)

    Wang Baozhen; Yin Jun

    1988-01-01

    Experimental studies were carried out on the removal of five species of aromatic nitro hydrocarbons by ozonation. Ultraviolet spectrograms with distinct absorption peaks were plotted for each of them. It has been found that the absorbances of aqueous solutions containing the single compounds mentioned above increase to different extents at the wave lengths ranging from 200 to 230 nanometers with increase of ozone dosages. This is ascribed to the nitrite ions splitting out of the benzene rings and being further oxidized to nitrate ions by ozonation. It has been indicated that the removal of the five species of aromatic nitro compounds by ozonation can well be expressed mathematically by first order reaction equations. Besides, the reaction constants and half-life periods for various species of the tested nitro compounds were calculated at different temperatures and pH. An ozonation effect index (OI) was developed in the study to express the degree of degradation of substrates by ozonation, by means of which the five aromatic nitro hydrocarbons were compared with each other and finally ranked in the following order from greatest to smallest degrees of degradation: p-nitroaniline > nitrobenzene > p-dinitrobenzene > p-nitrotoluene > m-dinitrobenzene. It has also found that the CODm/M ratio increases with ozone doses. This means that some easily degradable intermediates are produced, and increase in concentration with increase of ozone dose in the ozonation process. The mechanisms of removing the five aromatic nitro hydrocarbons are discussed from the viewpoint of orienting effects of substituent groups on the aromatic rings

  2. Genetic Diversity of Aromatic Rice Germplasm Revealed By SSR Markers

    Directory of Open Access Journals (Sweden)

    Saba Jasim Aljumaili

    2018-01-01

    Full Text Available Aromatic rice cultivars constitute a small but special group of rice and are considered the best in terms of quality and aroma. Aroma is one of the most significant quality traits of rice, and variety with aroma has a higher price in the market. This research was carried out to study the genetic diversity among the 50 aromatic rice accessions from three regions (Peninsular Malaysia, Sabah, and Sarawak with 3 released varieties as a control using the 32 simple sequence repeat (SSR markers. The objectives of this research were to quantify the genetic divergence of aromatic rice accessions using SSR markers and to identify the potential accessions for introgression into the existing rice breeding program. Genetic diversity index among the three populations such as Shannon information index (I ranged from 0.25 in control to 0.98 in Sabah population. The mean numbers of effective alleles and Shannon’s information index were 0.36 and 64.90%, respectively. Similarly, the allelic diversity was very high with mean expected heterozygosity (He of 0.60 and mean Nei’s gene diversity index of 0.36. The dendrogram based on UPGMA and Nei’s genetic distance classified the 53 rice accessions into 10 clusters. Analysis of molecular variance (AMOVA revealed that 89% of the total variation observed in this germplasm came from within the populations, while 11% of the variation emanated among the populations. These results reflect the high genetic differentiation existing in this aromatic rice germplasm. Using all these criteria and indices, seven accessions (Acc9993, Acc6288, Acc6893, Acc7580, Acc6009, Acc9956, and Acc11816 from three populations have been identified and selected for further evaluation before introgression into the existing breeding program and for future aromatic rice varietal development.

  3. Self-assembled electrical materials from contorted aromatics

    Science.gov (United States)

    Xiao, Shengxiong

    This thesis describes the design, synthesis, self-assembly and electrical properties of new types of contorted polycyclic aromatic hydrocarbons. These topologically interesting contorted aromatics show promising transistor characteristics as new building blocks for organic field-effect transistors (OFETs) at different length scales. In chapter 2, a class of pentacenes that are substituted along their long edges with aromatic rings were synthesized. Their solid-state assemblies were studied by X-ray crystallography. Their performance as thin film transistors (TFTs) and single crystal field effect transistors (SCFETs) were systematically evaluated. A structure-property relationship between these highly phenylated pentacenes was found. Chapter 3 explores the new concept of whether a non-planar aromatic core could yield efficacious electronic materials, as the ultimate success in the organic electronics will require a holistic approach to creating new building blocks. Synthesis, functionalization and assembly of a new type of contorted hexabenzocoronene (HBC) whose aromatic core is heavily distorted away from planarity due to the steric congestion around its proximal carbons were discussed. Structural studies by X-ray crystallography showed that these HBC molecules stack into columnar structures in the solid state, which are ideal for conduction. Chapter 4 describes that microscale liquid crystalline thin film OFETs of tetradodecyloxy HBC showed the best transistor properties of all discotic columnar materials. Chapter 5 details the fabrication and characterization of nanoscale single crystalline fiber OFETs of octadodecyloxyl HBC. In Chapter 6 we show that a molecular scale monolayer of HBC acid chlorides could be self-assembled on SiO2 insulating layer and could be organized laterally between the ends of 2 nm carbon nanotube gaps to form high quality FETs that act as environmental and chemical sensors. Chapter 7 details the enforced one-dimensional photoconductivity

  4. Equilibrium studies of the adsorption of aromatic disulfonates by Mg-Al oxide

    Science.gov (United States)

    Kameda, Tomohito; Umetsu, Mami; Kumagai, Shogo; Yoshioka, Toshiaki

    2018-03-01

    The removal of m-benzenedisulfonate (BDS2-) and 2,6-naphthalenedisulfonate (NDS2-) anions by Mg-Al oxide was investigated. Langmuir model best describes the adsorption of both aromatic disulfonate anions, with the maximum amount of uptake higher for BDS2-. Mg-Al oxide reacts easier with the aromatic disulfonate anion with higher charge density, a trend that is the opposite of that observed in aromatic sulfonate anions. After increasing the charge from -1 to -2, the removal of aromatic disulfonates by Mg-Al oxide is controlled by electrostatic interactions, instead of hydrophobic interactions that are dominant for aromatic sulfonate anions.

  5. Ambient aromatic hydrocarbon measurements at Welgegund, South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Jaars, K.; Beukes, J. P.; van Zyl, P. G.; Venter, A. D.; Josipovic, M.; Pienaar, J. J.; Vakkari, Ville; Aaltonen, H.; Laakso, H.; Kulmala, M.; Tiitta, P.; Guenther, Alex B.; Hellen, H.; Laakso, L.; Hakola, H.

    2014-07-11

    Aromatic hydrocarbons are associated with direct adverse human health effects and can have negative impacts on ecosystems due to their toxicity, as well as indirect negative effects through the formation of tropospheric ozone and secondary organic aerosol that affect human health, crop production and regional climate. Measurements were conducted at the Welgegund measurement station (South Africa) that is considered to be a regionally representative background site. However, the site is occasionally impacted by plumes from major anthropogenic source regions in the interior of South Africa, which include the western Bushveld Igneous Complex (e.g. platinum, base metal and ferrochrome smelters), the eastern Bushveld Igneous Complex (platinum and ferrochrome smelters), the Johannesburg-Pretoria metropolitan conurbation (>10 million people), the Vaal Triangle (e.g. petrochemical and industries), the Mpumalanga Highveld (e.g. coal-fired power plants and petrochemical industry) and also a region of anti-cyclonic recirculation of air mass over the interior of South Africa. The aromatic hydrocarbon measurements were conducted with an automated sampler on Tenax-TA and Carbopack-B adsorbent tubes with heated inlet for one year. Samples were collected twice a week for two hours during daytime and two hours 1 during night-time. A thermal desorption unit, connected to a gas chromatograph and a mass 2 selective detector was used for sample preparation and analysis. Results indicated that the 3 monthly median total aromatic hydrocarbon concentrations ranged between 0.01 to 3.1 ppb. 4 Benzene levels did not exceed local air quality standards. Toluene was the most abundant 5 species, with an annual median concentration of 0.63 ppb. No statistically significant 6 differences in the concentrations measured during daytime and night-time were found and no distinct seasonal patterns were observed. Air mass back trajectory analysis proved that the lack of seasonal cycles could be

  6. Stable Treemaps via Local Moves.

    Science.gov (United States)

    Sondag, Max; Speckmann, Bettina; Verbeek, Kevin

    2018-01-01

    Treemaps are a popular tool to visualize hierarchical data: items are represented by nested rectangles and the area of each rectangle corresponds to the data being visualized for this item. The visual quality of a treemap is commonly measured via the aspect ratio of the rectangles. If the data changes, then a second important quality criterion is the stability of the treemap: how much does the treemap change as the data changes. We present a novel stable treemapping algorithm that has very high visual quality. Whereas existing treemapping algorithms generally recompute the treemap every time the input changes, our algorithm changes the layout of the treemap using only local modifications. This approach not only gives us direct control over stability, but it also allows us to use a larger set of possible layouts, thus provably resulting in treemaps of higher visual quality compared to existing algorithms. We further prove that we can reach all possible treemap layouts using only our local modifications. Furthermore, we introduce a new measure for stability that better captures the relative positions of rectangles. We finally show via experiments on real-world data that our algorithm outperforms existing treemapping algorithms also in practice on either visual quality and/or stability. Our algorithm scores high on stability regardless of whether we use an existing stability measure or our new measure.

  7. On the performance of some aromaticity indices: a critical assessment using a test set.

    Science.gov (United States)

    Feixas, Ferran; Matito, Eduard; Poater, Jordi; Solà, Miquel

    2008-07-30

    Aromaticity is a central chemical concept widely used in modern chemistry for the interpretation of molecular structure, stability, reactivity, and magnetic properties of many compounds. As such, its reliable prediction is an important task of computational chemistry. In recent years, many methods to quantify aromaticity based on different physicochemical properties of molecules have been proposed. However, the nonobservable nature of aromaticity makes difficult to assess the performance of the numerous existing indices. In the present work, we introduce a series of fifteen aromaticity tests that can be used to analyze the advantages and drawbacks of a group of aromaticity descriptors. On the basis of the results obtained for a set of ten indicators of aromaticity, we conclude that indices based on the study of electron delocalization in aromatic species are the most accurate among those examined in this work. (c) 2008 Wiley Periodicals, Inc. J Comput Chem, 2008.

  8. The use of stable isotopes and gas chromatography/mass spectrometry in the identification of steroid metabolites in the equine

    International Nuclear Information System (INIS)

    Houghton, E.; Dumasia, M.C.; Teale, P.; Smith, S.J.; Cox, J.; Marshall, D.; Gower, D.B.

    1990-01-01

    Stable isotope gas chromatography/mass spectrometry has been used successfully in the elucidation of structures of urinary steroid metabolites in the horse and in the identification of metabolites isolated from in vivo perfusion and in vitro incubation studies using equine tissue preparations. Deuterium-labeled steroids, testosterone, dehydroepiandrosterone, and 5-androstene-3 beta,17 beta-diol have been synthesized by base-catalyzed isotope exchange methods and the products characterized by gas chromatography/mass spectrometry. [16,16(-2)H2]Dehydroepiandrosterone (plus radiolabeled dehydroepiandrosterone) was perfused into a testicular artery of a pony stallion and was shown to be metabolized into 2H2-labeled testosterone, 4-androstenedione, isomers of 5-androstene-3,17-diol, 19-hydroxytestosterone, and 19-hydroxy-4-androstenedione. In further studies, equine testicular minces have been incubated with 2H2-labeled and radiolabeled dehydroepiandrosterone and 5-androstene-3 beta, 17 beta-diol. The metabolites, whose identity was confirmed by stable isotope gas chromatography/mass spectrometry, proved the interconversion of the two substrates, as well as formation of testosterone and 4-androstenedione. The aromatization of dehydroepiandrosterone was also confirmed, together with the formation of an isomer of 5(10)-estrene-3,17-diol from both substrates showing 19-demethylation without concomitant aromatization. In studies of the feto-placental unit, the allantochorion was shown to aromatize [2H5]testosterone to [2H4]estradiol, the loss of one 2H from the substrate being consistent with aromatization of the A ring. The formation of 6-hydroxyestradiol was also confirmed in this study. The same technique has been valuable in determining the structure of two metabolites of nandrolone isolated from horse urine

  9. Exposure to polycyclic aromatic hydrocarbons with special focus on cancer

    Directory of Open Access Journals (Sweden)

    Thamaraiselvan Rengarajan

    2015-03-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are a group of compounds consisting of two or more fused aromatic rings. Most of them are formed during incomplete combustion of organic materials such as wood and fossil fuels, petroleum products, and coal. The composition of PAH mixtures varies with the source and is also affected by selective weathering effects in the environment. PAHs are ubiquitous pollutants frequently found in a variety of environments such as fresh water and marine sediments, the atmosphere, and ice. Due to their widespread distribution, the environmental pollution due to PAHs has aroused global concern. Many PAHs and their epoxides are highly toxic, mutagenic and/or carcinogenic to microorganisms as well as to higher forms of life including humans. The main aim of this review is to provide contemporary information on PAH sources, route of exposure, worldwide emission rate, and adverse effects on humans, especially with reference to cancer.

  10. Graphene growth by conversion of aromatic self-assembled monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Turchanin, Andrey [Institute of Physical Chemistry, Friedrich Schiller University Jena (Germany); Jena Center for Soft Matter (JCSM), Jena (Germany); Center for Energy and Environmental Chemistry Jena (CEEC), Jena (Germany); Abbe Center of Photonics (ACP), Jena (Germany)

    2017-11-15

    Despite present diversity of graphene production methods there is still a high demand for improvement of the existing production schemes or development of new. Here a method is reviewed to produce graphene employing aromatic self-assembled monolayers (SAMs) as molecular precursors. This method is based on electron irradiation induced crosslinking of aromatic SAMs resulting in their conversion into carbon nanomembranes (CNMs) with high thermal stability and subsequent pyrolysis of CNMs into graphene in vacuum or in the inert atmosphere. Depending on the production conditions, such as chemical structure of molecular precursors, irradiation and annealing parameters, various properties of the produced graphene sheets including shape, crystallinity, thickness, optical properties and electric transport can be adjusted. The assembly of CNM/graphene van der Waals heterostructures opens a flexible route to non-destructive chemical functionalization of graphene for a variety of applications in electronic and photonic devices. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Isotopic exchange of hydrogen in aromatic amino acids

    International Nuclear Information System (INIS)

    Pshenichnikova, A.B.; Karnaukhova, E.N.; Mitsner, B.I.

    1993-01-01

    The kinetics of the isotopic replacement of hydrogen in the aromatic amino acids L-tryptophan, L-tyrosine, and L-phenylalanine in solutions of deuterochloric and deuterosulfuric acids in deuterium oxide were investigated by PMR spectroscopy. The reactions were shown to be of first orders with respect both to the concentration of the substrate and to the activity of the deuterium ion. The isotopic effects of hydrogen and the values of the activation energy of H-D exchange in different positions of the aromatic ring in tryptophan and tyrosine were determined. The effect of properties of the medium on the rate of the isotopic exchange of hydrogen is discussed. 17 refs., 2 figs., 2 tabs

  12. Database of the Amazon aromatic plants and their essential oils

    Directory of Open Access Journals (Sweden)

    José Guilherme S. Maia

    2009-01-01

    Full Text Available The aromatic flora of the Amazon has been inventoried for 30 years. In this sense, were made over 500 field trips to collect over 2500 plants and to obtain more than 2000 essential oils and aroma concentrates, all of them submitted to GC and GC-MS. This work led to the creation of a database for the aromatic plants of the Amazon, which catalogs general information about 1250 specimens. The database has allowed the publication of the chemical composition of the oils and aromas of more than 350 species, associated with a larger number of chemical types. The essential oils of many species offer optimum conditions for economic exploitation and use in national and international market of fragrances, cosmetics, agricultural and household pesticides.

  13. Does toxicity of aromatic pollutants increase under remote atmospheric conditions?

    Science.gov (United States)

    Kroflič, Ana; Grilc, Miha; Grgić, Irena

    2015-03-09

    Aromatic compounds contribute significantly to the budget of atmospheric pollutants and represent considerable hazard to living organisms. However, they are only rarely included into atmospheric models which deviate substantially from field measurements. A powerful experimental-simulation tool for the assessment of the impact of low- and semi-volatile aromatic pollutants on the environment due to their atmospheric aqueous phase aging has been developed and introduced for the first time. The case study herein reveals that remote biotopes might be the most damaged by wet urban guaiacol-containing biomass burning aerosols. It is shown that only after the primary pollutant guaiacol has been consumed, its probably most toxic nitroaromatic product is largely formed. Revising the recent understanding of atmospheric aqueous phase chemistry, which is mostly concerned with the radical nitration mechanisms, the observed phenomenon is mainly attributed to the electrophilic nitrogen-containing reactive species. Here, their intriguing role is closely inspected and discussed from the ecological perspective.

  14. Advanced thermally stable jet fuels

    Energy Technology Data Exchange (ETDEWEB)

    Schobert, H.H.

    1999-01-31

    The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume

  15. Design, synthesis, and evaluation of bioactive molecules; Quantification of tricyclic pyrones from pharmacokinetic studies; Nanodelivery of siRNA; and Synthesis of viral protease inhibitors

    Science.gov (United States)

    Weerasekara, Sahani Manjitha

    simulation studies of dsRNA with these polymers revealed that nanoparticles can be formed between dsRNA and modified chitosan and PVP polymers. Nanocarriers of hydroxylated PVP (HO-PVP) and chitosan conjugated with polyethylene glycol (PEG) were synthesized, and analyzed using IR spectroscopy. Particle sizes and morphology were evaluated using AFM and encapsulation was studied using UV spectroscopy. However, the formation of stable nanoparticles with dsRNA could not be achieved with either of the polymers, and further efforts are ongoing to discover a better nanocarrier for nanodelivery of siRNA by using chitosan-galactose nanocarrier. In our efforts to discover a novel class of tripeptidyl anti-norovirus compounds that can strongly inhibit NV3CLpro, a set of tripeptidyl molecules were synthesized by modifying the P1 - P3 of the substrate peptide including a warhead. It was found that the replacement of P1 glutamine surrogate with triazole functionality does not improve the inhibitory activities of the compounds. In addition, the synthesis of a known dipeptidyl compound (GC376) was carried out for evaluating its efficacy on feline infectious peritonitis (FIP) in cats.

  16. Population Games, Stable Games, and Passivity

    Directory of Open Access Journals (Sweden)

    Michael J. Fox

    2013-10-01

    Full Text Available The class of “stable games”, introduced by Hofbauer and Sandholm in 2009, has the attractive property of admitting global convergence to equilibria under many evolutionary dynamics. We show that stable games can be identified as a special case of the feedback-system-theoretic notion of a “passive” dynamical system. Motivated by this observation, we develop a notion of passivity for evolutionary dynamics that complements the definition of the class of stable games. Since interconnections of passive dynamical systems exhibit stable behavior, we can make conclusions about passive evolutionary dynamics coupled with stable games. We show how established evolutionary dynamics qualify as passive dynamical systems. Moreover, we exploit the flexibility of the definition of passive dynamical systems to analyze generalizations of stable games and evolutionary dynamics that include forecasting heuristics as well as certain games with memory.

  17. Formic-acid-induced depolymerization of oxidized lignin to aromatics

    Science.gov (United States)

    Rahimi, Alireza; Ulbrich, Arne; Coon, Joshua J.; Stahl, Shannon S.

    2014-11-01

    Lignin is a heterogeneous aromatic biopolymer that accounts for nearly 30% of the organic carbon on Earth and is one of the few renewable sources of aromatic chemicals. As the most recalcitrant of the three components of lignocellulosic biomass (cellulose, hemicellulose and lignin), lignin has been treated as a waste product in the pulp and paper industry, where it is burned to supply energy and recover pulping chemicals in the operation of paper mills. Extraction of higher value from lignin is increasingly recognized as being crucial to the economic viability of integrated biorefineries. Depolymerization is an important starting point for many lignin valorization strategies, because it could generate valuable aromatic chemicals and/or provide a source of low-molecular-mass feedstocks suitable for downstream processing. Commercial precedents show that certain types of lignin (lignosulphonates) may be converted into vanillin and other marketable products, but new technologies are needed to enhance the lignin value chain. The complex, irregular structure of lignin complicates chemical conversion efforts, and known depolymerization methods typically afford ill-defined products in low yields (that is, less than 10-20wt%). Here we describe a method for the depolymerization of oxidized lignin under mild conditions in aqueous formic acid that results in more than 60wt% yield of low-molecular-mass aromatics. We present the discovery of this facile C-O cleavage method, its application to aspen lignin depolymerization, and mechanistic insights into the reaction. The broader implications of these results for lignin conversion and biomass refining are also considered.

  18. Cross-Linking Aromatic Polymers With Ionizing Radiation

    Science.gov (United States)

    Bell, Vernon L.; Havens, Stephen J.

    1987-01-01

    Resistance to heat and solvents increased. Certain aromatic polymers containing radiation-sensitive methylene groups cross-linked through methylene groups upon exposure to ionizing radiation. Cross-linked polymers resistant to most organic solvents and generally more resistant to high temperatures, with less tendency to creep under load. No significant embrittlement of parts fabricated from these polymers when degree of cross-linking, as controlled by irradiation dose, kept at moderate level.

  19. New insights into the formation of fungal aromatic polyketides

    OpenAIRE

    Crawford, Jason M.; Townsend, Craig A.

    2010-01-01

    Fungal aromatic polyketides constitute a large family of bioactive natural products and are synthesized by the non-reducing group of iterative polyketide synthases (NR-PKSs). Their diverse structures arise from selective enzymatic modifications of reactive enzyme-bound poly-β-keto intermediates. How iterative PKSs control starter unit selection, polyketide chain initiation and elongation, intermediate folding and cyclization, selective redox or modification reactions during assembly, and prod...

  20. Reactions of substituted aromatic molecules on the silicon(001) surface

    Science.gov (United States)

    Coutler, Sarah Kathryn

    Organic molecules possess unique physical and electronic properties that could be incorporated as components in new technologies, such as molecular electronics, biosensors and DNA chip arrays. While the properties of individual molecules often can be measured and predicted, the technological value of organic molecules for these types of applications requires the ability to understand and manipulate how physical and electronic properties are affected by bonding to a surface. Consequently, integration of organic systems with existing silicon-based technology necessitates a thorough investigation of the interfacial chemistry involved in adsorption processes. On a molecular scale, the delocalized electrons of a conjugated system could be used to carry charge from one point to another. Therefore, the interaction of pi-conjugated molecules with the technologically important Si(001) surface is of particular interest. X-ray Photoelectron Spectroscopy (XPS), Scanning Tunneling Microscopy (STM) and Fourier Transform Infrared (FTIR) Spectroscopy were used to investigate the bonding selectivity of several model aromatic molecules. Analysis of the infrared spectra of benzene, toluene and xylene suggest that these simple aromatic molecules covalently bond with the Si(001) surface, resulting in a loss of aromaticity. Studies of aromatic rings with other, more reactive substituent groups containing sulfur, oxygen, nitrogen, iodine or carbon atoms, indicate that the majority of these molecules preferentially adsorb to the surface through the substituent group. Careful consideration of the role played by both the electron-rich substituent groups and the silicon dimers in controlling selectivity leads to new insights regarding adsorption mechanisms. This knowledge, in turn, provides a method for selecting and designing molecules that will preferentially chemisorb on the Si(001) surface in a highly predictable manner. Preliminary studies correlating the chemical identity of the

  1. Kurdistan crude oils as feedstock for production of aromatics

    Directory of Open Access Journals (Sweden)

    Abdulsalam R. Karim

    2017-05-01

    Full Text Available Crude oils from various locations in Iraqi Kurdistan were fully evaluated, so that enables refiners to improve their operation by selecting the best crude oil that yields high naphtha content to be used as a catalytic reforming feedstock after determination of total sulfur content and then de sulfurizing them, then cyclizing or reforming these sweet naphtha cuts to produce aromatic fractions which can be split into benzene, toluene, and xylenes.

  2. Solubilities of oxygenated aromatic solids in pressurized hot water

    Czech Academy of Sciences Publication Activity Database

    Karásek, Pavel; Planeta, Josef; Roth, Michal

    2009-01-01

    Roč. 54, č. 5 (2009), s. 1457-1461 ISSN 0021-9568 R&D Projects: GA ČR GA203/07/0886; GA ČR GA203/08/1536 Institutional research plan: CEZ:AV0Z40310501 Keywords : oxygenated aromatics * solubility * pressurized hot water Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.695, year: 2009

  3. CHEMISTRY OF OXIDATION OF POLYCYCLIC AROMATIC HYDROCARBONS BY SOIL PSEUDOMONADS

    Science.gov (United States)

    Rogoff, Martin H.

    1962-01-01

    Rogoff, Martin H. (U.S. Bureau of Mines, Pittsburgh, Pa.). Oxidation of polycyclic aromatic hydrocarbons by soil pseudomonads. J. Bacteriol. 83:998–1004. 1962.—Substitution of phenanthrene by a methyl group at the 9-carbon blocks oxidation of the compound by a resting-cell suspension of a phenanthrene-grown soil pseudomonad. When 2-methylphenanthrene is provided, the oxidation rate is considerably higher; 3-methylphenanthrene is oxidized at a rate intermediate between the other two, even though the methyl group is attached to a carbon directly involved in ring splitting. Cells grown on naphthalene or anthracene oxidize phenanthrene at a much lower rate than cells grown with phenanthrene or 2-methylnaphthalene as the source of carbon. Naphthalene-grown cells also absorb less phenanthrene from aqueous solution than do their phenanthrene-grown counterparts. The data are in keeping with the hypothesis that polynuclear aromatic hydrocarbons attach to the relevant bacterial enzymes at carbon-carbon bonds of high electron density (K regions; localized double bonds), and that the ring-splitting reactions then occur at other bonds on the substrate molecule. The actual bond that undergoes fission is determined by the electronic and steric configurations of the enzyme-substrate complex. When linearly arranged aromatic compounds such as naphthalene or anthracene are attacked, attachment to an enzyme and ring splitting may take place on the same ring; angular aromatic compounds such as phenanthrene afford attachment to an enzyme at a bond in a ring other than the one containing the ring-splitting site. PMID:14493381

  4. Occurrence of fungi degrading aromatic hydrocarbons in activated sludge biocenoses

    Directory of Open Access Journals (Sweden)

    Anna Grabińska-Łoniewska

    2014-08-01

    Full Text Available A set of 21 strains of yeast-like microorganisms isolated from biocenoses of aerobic and anaerobic wastewater treatment systems were assayed for their ability to utilize aromatic hydrocarbons as a sole C-source. Basing on the achieved results, the highly biochemically active strains for application in enhancing of wastewaters and exhaust gases purification as well as soil bioremediation were selected.

  5. Ultrasound assisted regioselective sulfonation of aromatic compounds with sulfuric acid.

    Science.gov (United States)

    Qureshi, Ziyauddin S; Deshmukh, Krishna M; Jagtap, Sachin R; Nandurkar, Nitin S; Bhanage, Bhalchandra M

    2009-03-01

    A simple and convenient methodology for selective sulfonation of aromatic compounds using sulfuric acid under sonication is described. The present methodology shows a considerable enhancement in the reaction rate along with improved selectivity compared with the reactions performed under silent conditions. The effect of various parameters such as agitation speed, sulfuric acid concentration, and temperature on reaction system have been investigated and are explained on the basis of ultrasonically generated cavitational effects.

  6. MODELING GALACTIC EXTINCTION WITH DUST AND 'REAL' POLYCYCLIC AROMATIC HYDROCARBONS

    International Nuclear Information System (INIS)

    Mulas, Giacomo; Casu, Silvia; Cecchi-Pestellini, Cesare; Zonca, Alberto

    2013-01-01

    We investigate the remarkable apparent variety of galactic extinction curves by modeling extinction profiles with core-mantle grains and a collection of single polycyclic aromatic hydrocarbons. Our aim is to translate a synthetic description of dust into physically well-grounded building blocks through the analysis of a statistically relevant sample of different extinction curves. All different flavors of observed extinction curves, ranging from the average galactic extinction curve to virtually 'bumpless' profiles, can be described by the present model. We prove that a mixture of a relatively small number (54 species in 4 charge states each) of polycyclic aromatic hydrocarbons can reproduce the features of the extinction curve in the ultraviolet, dismissing an old objection to the contribution of polycyclic aromatic hydrocarbons to the interstellar extinction curve. Despite the large number of free parameters (at most the 54 × 4 column densities of each species in each ionization state included in the molecular ensemble plus the 9 parameters defining the physical properties of classical particles), we can strongly constrain some physically relevant properties such as the total number of C atoms in all species and the mean charge of the mixture. Such properties are found to be largely independent of the adopted dust model whose variation provides effects that are orthogonal to those brought about by the molecular component. Finally, the fitting procedure, together with some physical sense, suggests (but does not require) the presence of an additional component of chemically different very small carbonaceous grains.

  7. Formation of highly oxygenated organic molecules from aromatic compounds

    Directory of Open Access Journals (Sweden)

    U. Molteni

    2018-02-01

    Full Text Available Anthropogenic volatile organic compounds (AVOCs often dominate the urban atmosphere and consist to a large degree of aromatic hydrocarbons (ArHCs, such as benzene, toluene, xylenes, and trimethylbenzenes, e.g., from the handling and combustion of fuels. These compounds are important precursors for the formation of secondary organic aerosol. Here we show that the oxidation of aromatics with OH leads to a subsequent autoxidation chain reaction forming highly oxygenated molecules (HOMs with an O : C ratio of up to 1.09. This is exemplified for five single-ring ArHCs (benzene, toluene, o-/m-/p-xylene, mesitylene (1,3,5-trimethylbenzene and ethylbenzene, as well as two conjugated polycyclic ArHCs (naphthalene and biphenyl. We report the elemental composition of the HOMs and show the differences in the oxidation patterns of these ArHCs. A potential pathway for the formation of these HOMs from aromatics is presented and discussed. We hypothesize that AVOCs may contribute substantially to new particle formation events that have been detected in urban areas.

  8. Graphene magnetism induced by covalent adsorption of aromatic radicals.

    Science.gov (United States)

    Lin, He; Fratesi, Guido; Brivio, Gian Paolo

    2015-01-21

    We report a computational study of adsorption of aromatic radicals onto graphene, with the aim of understanding the effect of covalent molecular functionalization on the magnetic and structural properties of graphene. Our results show that the adsorption of an aromatic radical like phenyl also functionalized with donor or acceptor groups generates a band gap and two spin-dependent midgap states, one located above and the other below the Fermi energy of pristine graphene, which cause a net magnetic moment. Due to the interaction between the radical and graphene, we find that the carbon atom on the adsorption site is lifted out of the graphene plane, and its pz orbital is removed from the π band system, leaving the electrons in the other sublattice unpaired, which results in nonzero magnetism. But the band gap of the full system is insensitive to the different attached species and the midgap states are independent of the alignment of the molecular orbitals, so that the magnetic moment is the same for the various radicals studied. The net result of the radical adsorption is to have almost the same aromatic species as those in the gas phase but anchored on a surface.

  9. Ensemble modeling for aromatic production in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Matthew L Rizk

    2009-09-01

    Full Text Available Ensemble Modeling (EM is a recently developed method for metabolic modeling, particularly for utilizing the effect of enzyme tuning data on the production of a specific compound to refine the model. This approach is used here to investigate the production of aromatic products in Escherichia coli. Instead of using dynamic metabolite data to fit a model, the EM approach uses phenotypic data (effects of enzyme overexpression or knockouts on the steady state production rate to screen possible models. These data are routinely generated during strain design. An ensemble of models is constructed that all reach the same steady state and are based on the same mechanistic framework at the elementary reaction level. The behavior of the models spans the kinetics allowable by thermodynamics. Then by using existing data from the literature for the overexpression of genes coding for transketolase (Tkt, transaldolase (Tal, and phosphoenolpyruvate synthase (Pps to screen the ensemble, we arrive at a set of models that properly describes the known enzyme overexpression phenotypes. This subset of models becomes more predictive as additional data are used to refine the models. The final ensemble of models demonstrates the characteristic of the cell that Tkt is the first rate controlling step, and correctly predicts that only after Tkt is overexpressed does an increase in Pps increase the production rate of aromatics. This work demonstrates that EM is able to capture the result of enzyme overexpression on aromatic producing bacteria by successfully utilizing routinely generated enzyme tuning data to guide model learning.

  10. Formation of highly oxygenated organic molecules from aromatic compounds

    Science.gov (United States)

    Molteni, Ugo; Bianchi, Federico; Klein, Felix; El Haddad, Imad; Frege, Carla; Rossi, Michel J.; Dommen, Josef; Baltensperger, Urs

    2018-02-01

    Anthropogenic volatile organic compounds (AVOCs) often dominate the urban atmosphere and consist to a large degree of aromatic hydrocarbons (ArHCs), such as benzene, toluene, xylenes, and trimethylbenzenes, e.g., from the handling and combustion of fuels. These compounds are important precursors for the formation of secondary organic aerosol. Here we show that the oxidation of aromatics with OH leads to a subsequent autoxidation chain reaction forming highly oxygenated molecules (HOMs) with an O : C ratio of up to 1.09. This is exemplified for five single-ring ArHCs (benzene, toluene, o-/m-/p-xylene, mesitylene (1,3,5-trimethylbenzene) and ethylbenzene), as well as two conjugated polycyclic ArHCs (naphthalene and biphenyl). We report the elemental composition of the HOMs and show the differences in the oxidation patterns of these ArHCs. A potential pathway for the formation of these HOMs from aromatics is presented and discussed. We hypothesize that AVOCs may contribute substantially to new particle formation events that have been detected in urban areas.

  11. Selenium concentrations of selected medicinal and aromatic plants in Turkey.

    Science.gov (United States)

    Ozkutlu, Faruk; Sekeroglu, Nazim; Koca, Ufuk; Yazici, Gizem

    2011-10-01

    Recent scientific studies have proven the importance of trace elements on human health. The main food supplies are plants and animals, which are significant sources of these minerals. Studies on determining mineral compositions of herbs, spices and some other crops have increased all over the world. Published works revealed that spices, herbs and medicinal plants should be consumed to obtain beneficial trace elements. Selenium (Se), one of the most vital trace elements, has a significant role in human diet acting as a preventative agent against some serious illnesses. Despite numerous scientific works on mineral compositions of medicinal and aromatic plants, investigations of selenium content in these foods could not be successfully studied until recently due to the lack of suitable analytical methods for selenium analysis. Thus, publications on selenium concentrations of foods are recent. In this regard, selenium contents of some medicinal and aromatic plants commonly used as spices, herbal teas and traditional medicines in Turkey were studied in the present research. Selenium contents of the most used parts of these plants were analyzed by ICP-OES (Varian Vista-Pro, Australia). Of the analyzed 26 medicinal and aromatic plants, the highest Se concentration (1133 microg kg-1) was found in sweet basil (Ocimum basilicum L.) and the lowest in sumac (Rhus coriaria L.) fruits (11 microg kg(-1)).

  12. The genetic manipulation of medicinal and aromatic plants.

    Science.gov (United States)

    Gómez-Galera, Sonia; Pelacho, Ana M; Gené, Anna; Capell, Teresa; Christou, Paul

    2007-10-01

    Medicinal and aromatic plants have always been intimately linked with human health and culture. Plant-derived medicines constitute a substantial component of present day human healthcare systems in industrialized as well as developing countries. They are products of plant secondary metabolism and are involved in many other aspects of a plant's interaction with its immediate environment. The genetic manipulation of plants together with the establishment of in vitro plant regeneration systems facilitates efforts to engineer secondary product metabolic pathways. Advances in the cloning of genes involved in relevant pathways, the development of high throughput screening systems for chemical and biological activity, genomics tools and resources, and the recognition of a higher order of regulation of secondary plant metabolism operating at the whole plant level facilitate strategies for the effective manipulation of secondary products in plants. Here, we discuss advances in engineering metabolic pathways for specific classes of compounds in medicinal and aromatic plants and we identify remaining constraints and future prospects in the field. In particular we focus on indole, tropane, nicotine, isoquinoline alcaloids, monoterpenoids such as menthol and related compounds, diterpenoids such as taxol, sequiterpenoids such as artemisinin and aromatic amino acids.

  13. An Aromatic Cap Seals the Substrate Binding Site in an ECF-Type S Subunit for Riboflavin

    Energy Technology Data Exchange (ETDEWEB)

    Karpowich, Nathan K.; Song, Jinmei; Wang, Da-Neng

    2016-06-13

    ECF transporters are a family of active membrane transporters for essential micronutrients, such as vitamins and trace metals. Found exclusively in archaea and bacteria, these transporters are composed of four subunits: an integral membrane substrate-binding subunit (EcfS), a transmembrane coupling subunit (EcfT), and two ATP-binding cassette ATPases (EcfA and EcfA'). We have characterized the structural basis of substrate binding by the EcfS subunit for riboflavin from Thermotoga maritima, TmRibU. TmRibU binds riboflavin with high affinity, and the protein–substrate complex is exceptionally stable in solution. The crystal structure of riboflavin-bound TmRibU reveals an electronegative binding pocket at the extracellular surface in which the substrate is completely buried. Analysis of the intermolecular contacts indicates that nearly every available substrate hydrogen bond is satisfied. A conserved aromatic residue at the extracellular end of TM5, Tyr130, caps the binding site to generate a substrate-bound, occluded state, and non-conservative mutation of Tyr130 reduces the stability of this conformation. Using a novel fluorescence binding assay, we find that an aromatic residue at this position is essential for high-affinity substrate binding. Comparison with other S subunit structures suggests that TM5 and Loop5-6 contain a dynamic, conserved motif that plays a key role in gating substrate entry and release by S subunits of ECF transporters.

  14. Branched-chain and aromatic amino acids, insulin resistance and liver specific ectopic fat storage in overweight to obese subjects.

    Science.gov (United States)

    Haufe, S; Witt, H; Engeli, S; Kaminski, J; Utz, W; Fuhrmann, J C; Rein, D; Schulz-Menger, J; Luft, F C; Boschmann, M; Jordan, J

    2016-07-01

    Amino acids may interfere with insulin action, particularly in obese individuals. We hypothesized that increased circulating branched-chain and aromatic amino acids herald insulin resistance and ectopic fat storage, particularly hepatic fat accumulation. We measured fasting branched-chain and aromatic amino acids (tryptophan, tyrosine, and phenylalanine) by mass spectrometry in 111 overweight to obese subjects. We applied abdominal magnetic resonance imaging and spectroscopy to assess adipose tissue distribution and ectopic fat storage, respectively. Plasma branched-chain amino acids concentrations were related to insulin sensitivity and intrahepatic fat independent from adiposity, age and gender, but not to abdominal adipose tissue or intramyocellular fat. In weight stable overweight and obese individuals, branched-chain amino acid concentrations are specifically associated with hepatic fat storage and insulin resistance. Copyright © 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

  15. Extraction of Lanthanide and Actinide Ions from Aqueous Mixtures Using a Carboxylic Acid-Functionalized Porous Aromatic Framework

    Science.gov (United States)

    2016-01-01

    Porous aromatic frameworks (PAFs) incorporating a high concentration of acid functional groups possess characteristics that are promising for use in separating lanthanide and actinide metal ions, as required in the treatment of radioactive waste. These materials have been shown to be indefinitely stable to concentrated acids and bases, potentially allowing for multiple adsorption/stripping cycles. Additionally, the PAFs combine exceptional features from MOFs and inorganic/activated carbons giving rise to tunable pore surfaces and maximum chemical stability. Herein, we present a study of the adsorption of selected metal ions, Sr2+, Fe3+, Nd3+, and Am3+, from aqueous solutions employing a carbon-based porous aromatic framework, BPP-7 (Berkeley Porous Polymer-7). This material displays high metal loading capacities together with excellent adsorption selectivity for neodymium over strontium based on Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. Based in part upon X-ray absorption spectroscopy studies, the stronger adsorption of neodymium is attributed to multiple metal ion and binding site interactions resulting from the densely functionalized and highly interpenetrated structure of BPP-7. Recyclability and combustibility experiments demonstrate that multiple adsorption/stripping cycles can be completed with minimal degradation of the polymer adsorption capacity. PMID:27163056

  16. SiRNAs conjugated with aromatic compounds induce RISC-mediated antisense strand selection and strong gene-silencing activity.

    Science.gov (United States)

    Kubo, Takanori; Yanagihara, Kazuyoshi; Takei, Yoshifumi; Mihara, Keichiro; Sato, Yuichiro; Seyama, Toshio

    2012-10-05

    Short interference RNA (siRNA) is a powerful tool for suppressing gene expression in mammalian cells. In this study, we focused on the development of siRNAs conjugated with aromatic compounds in order to improve the potency of RNAi and thus to overcome several problems with siRNAs, such as cellular delivery and nuclease stability. The siRNAs conjugated with phenyl, hydroxyphenyl, naphthyl, and pyrenyl derivatives showed strong resistance to nuclease degradation, and were thermodynamically stable compared with unmodified siRNA. A high level of membrane permeability in HeLa cells was also observed. Moreover, these siRNAs exhibited enhanced RNAi efficacy, which exceeded that of locked nucleic acid (LNA)-modified siRNAs, against exogenous Renilla luciferase in HeLa cells. In particular, abundant cytoplasmic localization and strong gene-silencing efficacy were found in the siRNAs conjugated with phenyl and hydroxyphenyl derivatives. The novel siRNAs conjugated with aromatic compounds are promising candidates for a new generation of modified siRNAs that can solve many of the problems associated with RNAi technology. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Use of C-13 nuclear magnetic resonance to assess fossil fuel biodegradation: fate of (1-C-13)acenaphthene in cresosote polycyclic aromatic compound mixtures degraded by bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Selifonov, S.A.; Chapman, P.J.; Akkerman, S.B.; Gurst, J.E.; Bortiatynski, J.M.; Nanny, M.A.; Hatcher, P.G. [Maxygen Inc., Santa Clara, CA (United States)

    1998-04-01

    (1-C-13)acenaphthene, a tracer compound with a nuclear magnetic resonance (NMR)-active nucleus at the C-1 position, has been employed in conjunction with a standard broad-band-decoupled C-13-NMR spectroscopy technique to study the biodegradation of acenaphthene by various bacterial cultures degrading aromatic hydrocarbons of creosote. The study demonstrates the value of the stable isotope labelling approach and its ability to reveal incomplete mineralization even when as little as 2 to 3% of the substrate is incompletely oxidized, yielding products of partial transformation. The approach outlined may prove useful in assessing bioremediation performance.

  18. Molecular analysis of the role of two aromatic aminotransferases and a broad-specificity aspartate aminotransferase in the aromatic amino acid metabolism of Pyrococcus furiosus

    NARCIS (Netherlands)

    Ward, D.E.; Vos, de W.M.; Oost, van der J.

    2002-01-01

    The genes encoding aromatic aminotransferase II (AroAT II) and aspartate aminotransferase (AspAT) from Pyrococcus furiosus have been identified, expressed in Escherichia coli and the recombinant proteins characterized. The AroAT II enzyme was specific for the transamination reaction of the aromatic

  19. Tricyclic pharmacophore-based molecules as novel integrin alpha(v)beta3 antagonists. Part 2: synthesis of potent alpha(v)beta3/alpha(IIb)beta3 dual antagonists.

    Science.gov (United States)

    Ishikawa, Minoru; Kubota, Dai; Yamamoto, Mikio; Kuroda, Chizuko; Iguchi, Maki; Koyanagi, Akihiro; Murakami, Shoichi; Ajito, Keiichi

    2006-04-01

    We synthesized 4-aminopiperidine derivatives of our prototype integrin alpha(v)beta3 antagonist 1 in an attempt to increase the activity and water solubility. Introduction of one or two hydrophilic moieties into the central aromatic ring and/or the benzene ring at the C-terminus of 1 increased water solubility and enhanced inhibition of cell adhesion. The results of a structure-activity relationships (SAR) study indicated that the torsion angle between the central aromatic ring and the piperidine ring, and the acidity at the sulfonamide moiety, might be important for alpha(v)beta3 receptor binding activity. Some of these compounds are novel and potent alpha(v)beta3/alpha(IIb)beta3 dual antagonists with acceptable water solubility and a satisfactory early absorption, distribution, metabolism, excretion, and toxicity (ADMET) profile.

  20. Biotechnological production of aromatic compounds of the extended shikimate pathway from renewable biomass.

    Science.gov (United States)

    Lee, Jin-Ho; Wendisch, Volker F

    2017-09-10

    Aromatic chemicals that contain an unsaturated ring with alternating double and single bonds find numerous applications in a wide range of industries, e.g. paper and dye manufacture, as fuel additives, electrical insulation, resins, pharmaceuticals, agrochemicals, in food, feed and cosmetics. Their chemical production is based on petroleum (BTX; benzene, toluene, and xylene), but they can also be obtained from plants by extraction. Due to petroleum depletion, health compliance, or environmental issues such as global warming, the biotechnological production of aromatics from renewable biomass came more and more into focus. Lignin, a complex polymeric aromatic molecule itself, is a natural source of aromatic compounds. Many microorganisms are able to catabolize a plethora of aromatic compounds and interception of these pathways may lead to the biotechnological production of value-added aromatic compounds which will be discussed for Corynebacterium glutamicum. Biosynthesis of aromatic amino acids not only gives rise to l-tryptophan, L-tyrosine and l-phenylalanine, but also to aromatic intermediates such as dehydroshikimate or chorismate from which value-added aromatic compounds can be derived. In this review, we will summarize recent strategies for the biotechnological production of aromatic and related compounds from renewable biomass by Escherichia coli, Pseudomonas putida, C. glutamicum and Saccharomyces cerevisiae. In particular, we will focus on metabolic engineering of the extended shikimate pathway. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. A Critical Assessment of the Performance of Magnetic and Electronic Indices of Aromaticity

    Directory of Open Access Journals (Sweden)

    Miquel Solà

    2010-06-01

    Full Text Available The lack of reference aromatic systems in the realm of inorganic aromatic compounds makes the evaluation of aromaticity in all-metal and semimetal clusters a difficult task. To date, calculation of nucleus-independent chemical shifts (NICS has been the most widely used method to discuss aromaticity in these systems. In the first part of this work, we briefly review our previous studies, showing some pitfalls of the NICS indicator of aromaticity in organic molecules. Then, we refer to our study on the performance of some aromaticity indices in a series of 15 aromaticity tests, which can be used to analyze the advantages and drawbacks of aromaticity descriptors. It is shown that indices based on the study of electron delocalization are the most accurate among those analyzed in the series of proposed tests, while NICS(1zz and NICS(0πzz present the best behavior among NICS indices. In the second part, we discuss the use of NICS and electronic multicenter indices (MCI in inorganic clusters. In particular, we evaluate the aromaticity of two series of all-metal and semimetal clusters with predictable aromaticity trends by means of NICS and MCI. Results show that the expected trends are generally better reproduced by MCI than NICS. It is concluded that NICS(0π and NICS(0πzz are the kind of NICS that perform the best among the different NICS indices analyzed for the studied series of inorganic compounds.

  2. The reproductive and developmental toxicity of High Flash Aromatic Naphtha.

    Science.gov (United States)

    McKee, R H; Wong, Z A; Schmitt, S; Beatty, P; Swanson, M; Schreiner, C A; Schardein, J L

    1990-01-01

    Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent--High Flash Aromatic Naphtha. A program was initiated to assess the toxicological properties of High Flash Aromatic Naphtha since there may be human exposure through inhalation or external body contact. The current study was conducted to assess the potential for developmental toxicity in the mouse and for reproductive toxicity in the rat. In the developmental toxicity study in CD-1 mice, exposure of dams by inhalation to near lethal levels (1500 ppm) resulted in fetal mortality, reduced weight, delayed ossification, and an increased incidence of cleft palate. At 500 ppm, a level at which maternal weight gain was slightly reduced, fetal weight gain was also reduced, but there was no other evidence of developmental effects. The lowest exposure level (100 ppm) did not cause any maternal or developmental toxicity. There was no consistent evidence of reproductive toxicity in rats, even at exposure levels which resulted in significantly reduced parental weight gain. In addition, when parental exposure was stopped on GD (gestation day) 20, birth weights as well as postnatal survival were generally similar to control values, even in the 1500 ppm exposure group. Postnatal weight gain was also similar to controls early in weaning, but, if maternal exposure was reinitiated, weight gain was reduced in the high exposure group. However, when exposure was continued until delivery, pups in the high exposure group exhibited reduced litter size, birth weight and poor survival. Thus it was likely that the reduction in fetal weight

  3. Aromatic Hydrocarbons: Degrading Bacteria in the Desert Soil of Kuwait

    International Nuclear Information System (INIS)

    Al-Gounaim, M.; Diab, A.; Al-Hilali, A.; Abu-Shady, A. Sattar

    2005-01-01

    Soil samples of different levels of oil pollutants were collected from Kuwait's Burgan Oil Field, near an oil lake. The samples represented, highly polluted (8.0% w/w), moderately polluted (2.1%-3.4%) and slightly polluted (2.1%-3.4%) and slightly polluted (0.5- 0.8%). The aromatic fractions of the collected samples were in the range of (0.21-2.57g/100g) soil. (GC) analysis of the aromatic fractions of the resolution of the different individual (PAHs) revealed the presence of (16) different (PAHs) resolved from the aromatic fraction of the highly polluted sample (S3). (15), (14) and (13) individual (PAHs) were identified soil samples (S5), (S2) and (S1, S4, S6) respectively. The most frequent (PAH) was indeno (1, 2, 3-c, d) pyrene (22.5%-45.11%) followed chrysene (13.6%-19.48%). Eight carcinogenic (PAHs) were resolved from the aromatic fractions of the polluted samples. Total carcinogenic (PAHs) recorded in this study were in this study were in the range of (11.53) (forS4) - (510.98) (for S3) ppm. The counts of (CFU) of aromatic degraders (AD) were in the range of (3x10) - (110x 10) (CFU/g) soil (with a percent of (2.2%-69.6%)). The results show that, higher counts of (AD) were recorded from a highly polluted sample (S3), followed by the moderately polluted samples; total of (51) bacteria, that gave presumptive positive biodegradation activities, were isolated and identified (45.1%) of them were isolated and identified. (45.1%) of them were isolated from the highly polluted sample (S3). Total of (13) different species were identified of which Micrococcus luteus was more frequent (23.5) followed by Bacillus licheniformis (19.6%) and Bacillus subtilis (11.8%). The three Pseudomonas species collectively were presented by (11.8%). Five different species proved to be of good activities, they are: Bacillus brevis, Bacillus lichenoformis, Pseudomonas aeruginosa, Pseudomonas stutzeri and Pseudomonas flourescens. The ability of five species and their mixture was

  4. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part A-Monocyclic and Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

    2015-08-01

    Present study focused on the screening of bacterial consortium for biodegradation of monocyclic aromatic hydrocarbon (MAH) and polycyclic aromatic hydrocarbons (PAHs). Target compounds in the present study were naphthalene, acenaphthene, phenanthrene (PAHs), and benzene (MAH). Microbial consortia enriched with the above target compounds were used in screening experiments. Naphthalene-enriched consortium was found to be the most efficient consortium, based on its substrate degradation rate and its ability to degrade other aromatic pollutants with significantly high efficiency. Substrate degradation rate with naphthalene-enriched culture followed the order benzene > naphthalene > acenaphthene > phenanthrene. Chryseobacterium and Rhodobacter were discerned as the predominant species in naphthalene-enriched culture. They are closely associated to the type strain Chryseobacterium arthrosphaerae and Rhodobacter maris, respectively. Single substrate biodegradation studies with naphthalene (PAH) and benzene (MAH) were carried out using naphthalene-enriched microbial consortium (NAPH). Phenol and 2-hydroxybenzaldehyde were identified as the predominant intermediates during benzene and naphthalene degradation, respectively. Biodegradation of toluene, ethyl benzene, xylene, phenol, and indole by NAPH was also investigated. Monod inhibition model was able to simulate biodegradation kinetics for benzene, whereas multiple substrate biodegradation model was able to simulate biodegradation kinetics for naphthalene.

  5. Effects of grilling procedures on levels of polycyclic aromatic hydrocarbons in grilled meats.

    Science.gov (United States)

    Lee, Joon-Goo; Kim, Su-Yeon; Moon, Jung-Sik; Kim, Sheen-Hee; Kang, Dong-Hyun; Yoon, Hae-Jung

    2016-05-15

    Polycyclic aromatic hydrocarbons (PAHs) are chemicals formed when muscle meat is cooked using high-temperature methods, such as grilling directly over an open flame. PAHs have been found to be mutagenic-that is, they cause changes in DNA that may increase the risk of cancer. We investigated the effects of grilling procedures on the level of 4 PAHs; benzo[a]anthracene (B[a]A), chrysene (Chr), benzo[b]fluoranthene (B[b]F), and benzo[a]pyrene (B[a]P). PAHs were extracted and determined by gas chromatography with mass detection (GC-MS). With regard to barbecuing successive meat samples with the same batch of burning charcoal, it was observed that stable combustion contribute to reduction of PAHs. Significant reductions in the sum of the four PAHs were observed through treatments which removed meat drippings and smoke with alternative grilling apparatus. The sums of 4 PAHs were reduced 48-89% with dripping removed and 41-74% with the smoke removal treatment in grilled pork and beef meats than conventional grilling. We investigated the components of meats drippings. The major constituent of meat dripping was fat. The most important factor contributing to the production of PAHs in grilling was smoke resulting from incomplete combustion of fat dripped onto the fire. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Comparison of decomposition characteristics between aromatic and aliphatic VOCs using electron beam

    International Nuclear Information System (INIS)

    Kim, Jo-Chun

    2011-01-01

    The removal efficiency of n-decane (C 10 H 22 ) by electron beam was the highest among aliphatic VOCs of concern, and that of n-hexane (C 6 H 14 ), n-butane (C 4 H 10 ), and methane (CH 4 ) followed. On the other hand, in terms of aromatic VOC decomposition efficiencies, benzene (C 6 H 6 ) decomposition was the lowest and that of toluene (C 7 H 8 ), ethylbenzene (C 8 H 10 ), and p-xylene (C 8 H 10 ) were similar. It was also found that there was increase in by-product (untreated VOC, CO, CO 2 , O 3 , and other compounds) formation as well as all VOC removal efficiencies. It was demonstrated that the removal efficiency of VOC increased as its concentration decreased and the irradiation dose increased. In addition, low removal efficiency was observed because helium was relatively stable compared to the other gases, and nothing but electrons produced by electron accelerator reacted with VOC. It was also found that relative humidity had some effects on the decomposition rates of VOC. The removal efficiency at the 100% RH condition was slightly higher than that at 7.4% RH (dry condition) due to OH radical formation. (author)

  7. NATO Advanced Research and CNRS Workshop on Polycyclic Aromatic Hydrocarbons and Astrophysics

    CERN Document Server

    d’Hendecourt, L; Boccara, N

    1987-01-01

    The near Infra-Red emission of the Interstellar Medium is a very puzzling subject. In the brightest regions, where spectroscopic observa­ tions are possible from the ground, several bands (3.3 - 3.4 - 6.2 - 7.7 - 8.6 - 11.3 ~m) have been observed since 1973. The absence of satisfying explanation was so obvious that they were called "Unidenti­ fied IR Emission Bands". The puzzle still increased when were known the first results of the general IR sky survey made by the satellite IRAS. On a large scale, the near IR emission of the Interstellar medium was expected to be very small but it was observed to be about one third of the total IR emission for our own galaxy ..• The situation has moved in 1984 when it was suggested that a class of stable organic molecules, the Polycyclic Aromatic Hydrocarbons (PAH's) could be at the origin of this near IR emission. Initially based on the required refractory character of particules that should be heated to high temperature without subliming, this hypothesis leads to a s...

  8. Designability of Aromatic Interaction Networks at E. coli Bacterioferritin B-Type Channels

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2017-12-01

    Full Text Available The bacterioferritin from E. coli (BFR, a maxi-ferritin made of 24 subunits, has been utilized as a model to study the fundamentals of protein folding and self-assembly. Through structural and computational analyses, two amino acid residues at the B-site interface of BFR were chosen to investigate the role they play in the self-assembly of nano-cage formation, and the possibility of building aromatic interaction networks at B-type protein–protein interfaces. Three mutants were designed, expressed, purified, and characterized using transmission electron microscopy, size exclusion chromatography, native gel electrophoresis, and temperature-dependent circular dichroism spectroscopy. All of the mutants fold into α-helical structures and possess lowered thermostability. The double mutant D132W/N34W was 12 °C less stable than the wild type, and was also the only mutant for which cage-like nanostructures could not be detected in the dried, surface-immobilized conditions of transmission electron microscopy. Two mutants—N34W and D132W/N34W—only formed dimers in solution, while mutant D132W favored the 24-mer even more robustly than the wild type, suggesting that we were successful in designing proteins with enhanced assembly properties. This investigation into the structure of this important class of proteins could help to understand the self-assembly of proteins in general.

  9. Action of a Fluoranthene-Utilizing Bacterial Community on Polycyclic Aromatic Hydrocarbon Components of Creosote

    Science.gov (United States)

    Mueller, J. G.; Chapman, P. J.; Pritchard, P. H.

    1989-01-01

    Cultures enriched by serial transfer through a mineral salts medium containing fluoranthene were used to establish a stable, seven-member bacterial community from a sandy soil highly contaminated with coal tar creosote. This community exhibited an ability to utilize fluoranthene as the sole carbon source for growth, as demonstrated by increases in protein concentration and changes in absorption spectra when grown on fluoranthene in liquid culture. Biotransformation of other polycyclic aromatic hydrocarbons (PAHs) was verified by demonstrating their disappearance from an artificial PAH mixture by capillary gas chromatography. When grown on fluoranthene as the sole carbon source and subsequently exposed to fluoranthene plus 16 additional PAHs typical of those found in creosote, this community transformed all PAHs present in this defined mixture. After 3 days of incubation, 13 of the original 17 PAH components were degraded to levels below the limit of detection (10 ng/liter). Continued incubation resulted in extensive degradation of the remaining four compounds. The ability of this community to utilize a high-molecular-weight PAH as the sole carbon source, in conjunction with its ability to transform a diverse array of PAHs, suggests that it may be of value in the bioremediation of environments contaminated with PAHs, such as those impacted by creosote. PMID:16348069

  10. Action of a fluoranthene-utilizing bacterial community on polycyclic aromatic hydrocarbon components of creosote.

    Science.gov (United States)

    Mueller, J G; Chapman, P J; Pritchard, P H

    1989-12-01

    Cultures enriched by serial transfer through a mineral salts medium containing fluoranthene were used to establish a stable, seven-member bacterial community from a sandy soil highly contaminated with coal tar creosote. This community exhibited an ability to utilize fluoranthene as the sole carbon source for growth, as demonstrated by increases in protein concentration and changes in absorption spectra when grown on fluoranthene in liquid culture. Biotransformation of other polycyclic aromatic hydrocarbons (PAHs) was verified by demonstrating their disappearance from an artificial PAH mixture by capillary gas chromatography. When grown on fluoranthene as the sole carbon source and subsequently exposed to fluoranthene plus 16 additional PAHs typical of those found in creosote, this community transformed all PAHs present in this defined mixture. After 3 days of incubation, 13 of the original 17 PAH components were degraded to levels below the limit of detection (10 ng/liter). Continued incubation resulted in extensive degradation of the remaining four compounds. The ability of this community to utilize a high-molecular-weight PAH as the sole carbon source, in conjunction with its ability to transform a diverse array of PAHs, suggests that it may be of value in the bioremediation of environments contaminated with PAHs, such as those impacted by creosote.

  11. Study of improved resins for advanced supersonic technology composites. Part 1: Heteroaromatic polymers containing ether groups. Part 2: Curing chemistry of aromatic polymers and composite studies

    Science.gov (United States)

    Takekoshi, T.; Hillig, W. B.; Mellinger, G. A.

    1975-01-01

    Fourteen ether-containing, aromatic dianhydrides have been synthesized from N-phenyl-3 or 4-nitrophthalimide and various bisphenols. The process involves nucleophilic displacement of activated nitro groups with bisphenolate ions. Ether-containing dianhydrides were indefinitely stable in the presence of atmospheric moisture. One-step, high temperature solution polymerization of the ether-containing dianhydrides with m-phenylene diamine, 4,4'-oxydianiline and 1, 3-bis(4-aminophenoxy)benzene afforded 42 polyetherimides. The polyetherimides were all soluble in m-cresol except two which were found to be crystalline. The glass transition temperatures of the polyetherimides ranged from 178 to 277 C. Soluble polybenzimidazopyrrolones containing ether groups were also prepared from the same ether-containing dianhydrides and aromatic tetraamines by one-step solution polymerization. Using low molecular weight polyetherimides, various thermoset resin systems were developed and tested as matrices for fiber-reinforced composites. The curing chemistry involving reaction of the phthalonitrile group and the o-diaminophenyl group was found to be generally applicable to crosslinking various aromatic polymers other than polyimides.

  12. Gas phase thermal diffusion of stable isotopes

    International Nuclear Information System (INIS)

    Eck, C.F.

    1979-01-01

    The separation of stable isotopes at Mound Facility is reviewed from a historical perspective. The historical development of thermal diffusion from a laboratory process to a separation facility that handles all the noble gases is described. In addition, elementary thermal diffusion theory and elementary cascade theory are presented along with a brief review of the uses of stable isotopes

  13. physico-chemical and stable isotopes

    African Journals Online (AJOL)

    This paper details the mineralogical, chemical and stable isotope abundances of calcrete in the Letlhakeng fossil valley. The stable isotope abundances (O and C) of calcretes yielded some values which were tested against the nature of the calcretes – pedogenic or groundwater type. The Kgalagadi (Kalahari) is a vast ...

  14. Modelling stable atmospheric boundary layers over snow

    NARCIS (Netherlands)

    Sterk, H.A.M.

    2015-01-01

    Thesis entitled:

    Modelling Stable Atmospheric Boundary Layers over Snow

    H.A.M. Sterk

    Wageningen, 29th of April, 2015

    Summary

    The emphasis of this thesis is on the understanding and forecasting of the Stable Boundary Layer (SBL) over snow-covered surfaces. SBLs

  15. Modelling stable atmospheric boundary layers over snow

    NARCIS (Netherlands)

    Sterk, H.A.M.

    2015-01-01

    Thesis entitled: Modelling Stable Atmospheric Boundary Layers over Snow H.A.M. Sterk Wageningen, 29th of April, 2015 Summary The emphasis of this thesis is on the understanding and forecasting of the Stable Boundary Layer (SBL) over snow-covered surfaces. SBLs typically form at night and in polar

  16. Stable isotopes and biomarkers in microbial ecology

    NARCIS (Netherlands)

    Boschker, H.T.S.; Middelburg, J.J.

    2002-01-01

    The use of biomarkers in combination with stable isotope analysis is a new approach in microbial ecology and a number of papers on a variety of subjects have appeared. We will first discuss the techniques for analysing stable isotopes in biomarkers, primarily gas chromatography-combustion-isotope

  17. Stable Agrobacterium -mediated transformation of the halophytic ...

    African Journals Online (AJOL)

    Stable Agrobacterium-mediated transformation of the halophytic Leymus chinensis (Trin.) Yan-Lin Sun, Soon-Kwan Hong. Abstract. In this study, an efficient procedure for stable Agrobacterium-mediated transformation of Leymus chinensis (Trin.) was established. Agrobacterium tumefaciens strain EHA105, harboring a ...

  18. Structure of acid-stable carmine.

    Science.gov (United States)

    Sugimoto, Naoki; Kawasaki, Yoko; Sato, Kyoko; Aoki, Hiromitsu; Ichi, Takahito; Koda, Takatoshi; Yamazaki, Takeshi; Maitani, Tamio

    2002-02-01

    Acid-stable carmine has recently been distributed in the U.S. market because of its good acid stability, but it is not permitted in Japan. We analyzed and determined the structure of the major pigment in acid-stable carmine, in order to establish an analytical method for it. Carminic acid was transformed into a different type of pigment, named acid-stable carmine, through amination when heated in ammonia solution. The features of the structure were clarified using a model compound, purpurin, in which the orientation of hydroxyl groups on the A ring of the anthraquinone skeleton is the same as that of carminic acid. By spectroscopic means and the synthesis of acid-stable carmine and purpurin derivatives, the structure of the major pigment in acid-stable carmine was established as 4-aminocarminic acid, a novel compound.

  19. Stable Fly, (L., Dispersal and Governing Factors

    Directory of Open Access Journals (Sweden)

    Allan T. Showler

    2015-01-01

    Full Text Available Although the movement of stable fly, Stomoxys calcitrans (L., has been studied, its extent and significance has been uncertain. On a local scale (13 km is mainly wind-driven by weather fronts that carry stable flies from inland farm areas for up to 225 km to beaches of northwestern Florida and Lake Superior. Stable flies can reproduce for a short time each year in washed-up sea grass, but the beaches are not conducive to establishment. Such movement is passive and does not appear to be advantageous to stable fly's survival. On a regional scale, stable flies exhibit little genetic differentiation, and on the global scale, while there might be more than one “lineage”, the species is nevertheless considered to be panmictic. Population expansion across much of the globe likely occurred from the late Pleistocene to the early Holocene in association with the spread of domesticated nomad livestock and particularly with more sedentary, penned livestock.

  20. Volatile Compounds in Dry Dog Foods and Their Influence on Sensory Aromatic Profile

    OpenAIRE

    Koppel, Kadri; Adhikari, Koushik; Donfrancesco, Brizio Di

    2013-01-01

    The aim of this study was to determine volatile compounds in dry dog foods and their possible influence on sensory aromatic profile. Grain-free dry dog foods were compared to dry dog foods manufactured with grain, but also with different protein sources for their aromatic volatiles. Solid-phase microextraction/gas chromatography/mass spectrometry was used to determine the aromatic compounds present in the headspace of these samples. Partial Least Squares regression was performed to correlate ...

  1. Understanding substituent effects in noncovalent interactions involving aromatic rings.

    Science.gov (United States)

    Wheeler, Steven E

    2013-04-16

    Noncovalent interactions involving aromatic rings such as π-stacking, cation/π, and anion/π interactions are central to many areas of modern chemistry. Decades of experimental studies have provided key insights into the impact of substituents on these interactions, leading to the development of simple intuitive models. However, gas-phase computational studies have raised some doubts about the physical underpinnings of these widespread models. In this Account we review our recent efforts to unravel the origin of substituent effects in π-stacking and ion/π interactions through computational studies of model noncovalent dimers. First, however, we dispel the notion that so-called aromatic interactions depend on the aromaticity of the interacting rings by studying model π-stacked dimers in which the aromaticity of one of the monomers can be "switched off". Somewhat surprisingly, the results show that not only is aromaticity unnecessary for π-stacking interactions, but it actually hinders these interactions to some extent. Consequently, when thinking about π-stacking interactions, researchers should consider broader classes of planar molecules, not just aromatic systems. Conventional models maintain that substituent effects in π-stacking interactions result from changes in the aryl π-system. This view suggests that π-stacking interactions are maximized when one ring is substituted with electron-withdrawing groups and the other with electron donors. In contrast to these prevailing models, we have shown that substituent effects in π-stacking interactions can be described in terms of direct, local interactions between the substituents and the nearby vertex of the other arene. As a result, in polysubstituted π-stacked dimers the substituents operate independently unless they are in each other's local environment. This means that in π-stacked dimers in which one arene is substituted with electron donors and the other with electron acceptors the interactions will

  2. Kinetic analysis of reversible inhibition of 16alpha-hydroxyandrostenedione aromatization in human placental microsomes by suicide substrates of androstenedione aromatization.

    Science.gov (United States)

    Numazawa, Mitsuteru; Mutsumi, Ayako; Tachibana, Mii; Yoshimura, Akiko

    2003-06-01

    To gain insight into the catalytic function of aromatase and its substrate specificity, we studied reversible inhibition of 16alpha-hydroxyandrostenedione (16alpha-OHAD) aromatization in human placental microsomes by several suicide substrates of androstenedione (AD) aromatization, including 4-hydroxyAD (1), 6-oxoAD (2) and its 19-hydroxy analogue 3, androst-5-ene-4,7,17-trione (4), and 10beta-acetoxyandrost-5-en-7,17-dione (5) that, in contrast, do not cause a suicide inactivation of 16alpha-OHAD aromatization. All inhibitors examined blocked 16alpha-OHAD aromatization in a competitive manner with apparent K(i) values ranging from 0.50 to 980 nM. The relative K(i) values between inhibitors 1-5 obtained in the 16alpha-OHAD aromatization experiments were markedly different from those obtained in the AD aromatization experiments. The results predict that all inhibitors examined bind to the 16alpha-OHAD binding site in a manner that does not cause suicide inactivation of 16alpha-OHAD aromatization. These findings would be useful for understanding the active (binding) site structure as well as the catalytic function of aromatase.

  3. An ethnopharmacological study of aromatic Uyghur medicinal plants in Xinjiang, China.

    Science.gov (United States)

    Zhao, Lu; Tian, Shuge; Wen, E; Upur, Halmuart

    2017-12-01

    An ethnobotanical survey was completed in a remote village and surrounding country of Xinjiang, where most Uyghur medicinal plants could be collected. This work clarifies and increases ethnobotanical data. We surveyed and organized aromatic medicinal plants that are commonly used in clinical settings to provide a significant reference for studying new medical activities. In the survey, informants who have traditional knowledge on aromatic Uyghur medicinal plants were interviewed between March 2014 and September 2014. Aromatic medicinal plant species and pertinent information were collected. Some therapeutic methods and modes of preparation of traditional aromatic medicinal plants were found. A total of 86 aromatic medicinal plant species belonging to 36 families were included in our study. We identified 34 plant species introduced from different regions such as Europe, India and Mediterranean areas. Fruits and whole plants were the most commonly used parts of plant, and most aromatic medicinal plants could be applied as medicine and food. We assigned the medicinal plants a use value (UV). Knowing the UV of species is useful in determining the use reliability and pharmacological features of related plants. Xinjiang is an area in which indigenous aromatic medicinal plants are diversely used and has therefore established a sound dimensional medical healthcare treatment system. Some aromatic Uyghur medicinal plants are on the verge of extinction. Hence, further strategies for the conservation of these aromatic medicinal plants should be prioritized.

  4. Aromaticity of benzene in condensed phases. A case of a benzene-water system

    Science.gov (United States)

    Zborowski, Krzysztof K.

    2014-05-01

    A theoretical Density Functional Theory study was performed for a benzene molecule in water cages. Two DFT functionals (B3LYP and BLYP) were employed. The optimized geometries of the studied clusters were used to calculate the aromaticity of benzene in a condensed phase using the aromaticity indices: HOMA, NICS, PDI, and H. The results were compared with aromaticity of a single benzene molecule in the gas phase and in the solvent environment provided by the PCM continuum model. It is argued that high aromaticity of benzene in the gas phase is retained in the water environment.

  5. Design and screening of ASIC inhibitors based on aromatic diamidines for combating neurological disorders.

    Science.gov (United States)

    Chen, Xuanmao; Orser, Beverley A; MacDonald, John F

    2010-12-01

    Acid sensing ion channels (ASICs) are implicated in various brain functions including learning and memory and are involved in a number of neurological disorders such as pain, ischemic stroke, depression, and multiple sclerosis. We have recently defined ASICs as one of receptor targets of aromatic diamidines in neurons. Aromatic diamidines are DNA-binding agents and have long been used in the treatment of leishmaniasis, trypanosomiasis, pneumocystis pneumonia and babesiosis. Moreover, some aromatic diamidines are used as skin-care and baby products and others have potential to suppress tumor growth or to combat malaria. A large number of aromatic diamidines or analogs have been synthesized. Many efforts are being made to optimize the therapeutic spectrum of aromatic diamidines, i.e. to reduce toxicity, increase oral bioavailability and enhance their penetration of the blood-brain barrier. Aromatic diamidines therefore provide a shortcut of screening for selective ASIC inhibitors with therapeutic potential. Intriguingly nafamostat, a protease inhibitor for treating acute pancreatitis, also inhibits ASIC activities. Aromatic diamidines and nafamostat have many similarities although they belong to distinct classes of medicinal agents for curing different diseases. Here we delineate background, clinical application and drug development of aromatic diamidines that could facilitate the screening for selective ASIC inhibitors for research purposes. Further studies may lead to a drug with therapeutic value and extend the therapeutic scope of aromatic diamidines to combat neurological diseases. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Physico-Chemical Speciation and Ocean Fluxes of Polycyclic Aromatic Hydrocarbons

    National Research Council Canada - National Science Library

    Gustafsson, Orjan

    1997-01-01

    Partitioning of ecotoxicologically significant polycyclic aromatic hydrocarbons (PAHs) to non-aqueous, particularly colloidal and soot, phases results in a decrease in their, directly bioavailable, dissolved fractions...

  7. Validation of the recently developed aromaticity index D3BIA for benzenoid systems. Case study: acenes.

    Science.gov (United States)

    Araújo, Diógenes Mendes; da Costa, Tamires Ferreira; Firme, Caio Lima

    2015-09-01

    There are four types of aromaticity criteria: energetic, electronic, magnetic and geometric. The delocalization, density and degeneracy-based index of aromaticity, D3BIA, is an electronic aromaticity index from QTAIM that is not reference dependent and can be used for aromatic, homoaromatic, sigma aromatic and other aromatic systems with varying ring size containing hetereoatoms or not. We used B3LYP, MP2 and MP3 methods to search for linear relations between well-known aromaticity indices and D3BIA for a series of acenes. We found that the D3BIA versus FLU correlation exceeded 91 % and reasonably good correlations exist between D3BIA and HOMA and between D3BIA and PDI. Previous works have shown that D3BIA can be used for homoaromatic systems and tetrahedrane derivatives (sigma aromaticity), but no previous work has validated D3BIA for benzenoid systems. This is the first time we have shown that D3BIA can be used successfully for benzenoid systems, for example, acenes. This work supports and validates the use of D3BIA in classical aromatic systems.

  8. Engineered biosynthesis of bacterial aromatic polyketides in Escherichia coli.

    Science.gov (United States)

    Zhang, Wenjun; Li, Yanran; Tang, Yi

    2008-12-30

    Bacterial aromatic polyketides are important therapeutic compounds including front line antibiotics and anticancer drugs. It is one of the last remaining major classes of natural products of which the biosynthesis has not been reconstituted in the genetically superior host Escherichia coli. Here, we demonstrate the engineered biosynthesis of bacterial aromatic polyketides in E. coli by using a dissected and reassembled fungal polyketide synthase (PKS). The minimal PKS of the megasynthase PKS4 from Gibberella fujikuroi was extracted by using two approaches. The first approach yielded a stand-alone Ketosynthase (KS)_malonyl-CoA:ACP transferase (MAT) didomain and an acyl-carrier protein (ACP) domain, whereas the second approach yielded a compact PKS (PKS_WJ) that consists of KS, MAT, and ACP on a single polypeptide. Both minimal PKSs produced nonfungal polyketides cyclized via different regioselectivity, whereas the fungal-specific C2-C7 cyclization mode was not observed. The kinetic properties of the two minimal PKSs were characterized to confirm both PKSs can synthesize polyketides with similar efficiency as the parent PKS4 megasynthase. Both minimal PKSs interacted effectively with exogenous polyketide cyclases as demonstrated by the synthesis of predominantly PK8 3 or NonaSEK4 6 in the presence of a C9-C14 or a C7-C12 cyclase, respectively. When PKS_WJ and downstream tailoring enzymes were expressed in E. coli, the expected nonaketide anthraquinone SEK26 was recovered in good titer. High-cell density fermentation was performed to demonstrate the scale-up potential of the in vivo platform for the biosynthesis of bacterial polyketides. Using engineered fungal PKSs can therefore be a general approach toward the heterologous biosynthesis of bacterial aromatic polyketides in E. coli.

  9. Aromatic-Mediated Carbohydrate Recognition in Processive Serratia marcescens Chitinases.

    Science.gov (United States)

    Jana, Suvamay; Hamre, Anne Grethe; Wildberger, Patricia; Holen, Matilde Mengkrog; Eijsink, Vincent G H; Beckham, Gregg T; Sørlie, Morten; Payne, Christina M

    2016-02-25

    Microorganisms use a host of enzymes, including processive glycoside hydrolases, to deconstruct recalcitrant polysaccharides to sugars. Processive glycoside hydrolases closely associate with polymer chains and repeatedly cleave glycosidic linkages without dissociating from the crystalline surface after each hydrolytic step; they are typically the most abundant enzymes in both natural secretomes and industrial cocktails by virtue of their significant hydrolytic potential. The ubiquity of aromatic residues lining the enzyme catalytic tunnels and clefts is a notable feature of processive glycoside hydrolases. We hypothesized that these aromatic residues have uniquely defined roles, such as substrate chain acquisition and binding in the catalytic tunnel, that are defined by their local environment and position relative to the substrate and the catalytic center. Here, we investigated this hypothesis with variants of Serratia marcescens family 18 processive chitinases ChiA and ChiB. We applied molecular simulation and free energy calculations to assess active site dynamics and ligand binding free energies. Isothermal titration calorimetry provided further insight into enthalpic and entropic contributions to ligand binding free energy. Thus, the roles of six aromatic residues, Trp-167, Trp-275, and Phe-396 in ChiA, and Trp-97, Trp-220, and Phe-190 in ChiB, have been examined. We observed that point mutation of the tryptophan residues to alanine results in unfavorable changes in the free energy of binding relative to wild-type. The most drastic effects were observed for residues positioned at the "entrances" of the deep substrate-binding clefts and known to be important for processivity. Interestingly, phenylalanine mutations in ChiA and ChiB had little to no effect on chito-oligomer binding, in accordance with the limited effects of their removal on chitinase functionality.

  10. Antifungal activity of polycyclic aromatic hydrocarbons against Ligninolytic fungi

    Directory of Open Access Journals (Sweden)

    Memić Mustafa

    2011-01-01

    Full Text Available Environmental contamination by polycyclic aromatic hydrocarbons (PAHs has caused increasing concern because of their known, or suspected, carcinogenic and mutagenic effects. Polycyclic aromatic hydrocarbons occurring in the environment are usually the result of the incomplete combustion of carbon containing materials. The main sources of severe PAHs contamination in soil come from fossil fuels, i.e. production or use of fossil fuels or their products, such as coal tar and creosote. Creosote is used as a wood preservation for railway ties, bridge timbers, pilling and large-sized lumber. It consists mainly of PAHs, phenol and cresol compounds that cause harmful health effects. Research on biodegradation has shown that a special group of microorganisms, the white-rot fungi and brown-rot fungi, has a remarkable potential to degrade PAHs. This paper presents a study of the antifungal activity of 12 selected PAHs against two ligninolytic fungi Hypoxylon fragiforme (white rot and Coniophora puteana (brown rot. The antifungal activity of PAHs was determined by the disc-diffusion method by measuring the diameter of the zone of inhibition. The results showed that the antifungal activity of the tested PAHs (concentration of 2.5 mmol/L depends on the their properties such as molar mass, solubility in water, values of log Kow, ionization potential and Henry’s Law constant as well as number of aromatic rings, molecule topology or pattern of ring linkage. Among the 12 investigated PAHs, benzo(k fluoranthene with five rings, and pyrene with four cyclic condensed benzene rings showed the highest antifungal activity.

  11. Design and Elaboration of a Tractable Tricyclic Scaffold To Synthesize Druglike Inhibitors of Dipeptidyl Peptidase-4 (DPP-4), Antagonists of the C-C Chemokine Receptor Type 5 (CCR5), and Highly Potent and Selective Phosphoinositol-3 Kinase δ (PI3Kδ) Inhibitors.

    Science.gov (United States)

    Schwehm, Carolin; Kellam, Barrie; Garces, Aimie E; Hill, Stephen J; Kindon, Nicholas D; Bradshaw, Tracey D; Li, Jin; Macdonald, Simon J F; Rowedder, James E; Stoddart, Leigh A; Stocks, Michael J

    2017-02-23

    A novel molecular scaffold has been synthesized, and its incorporation into new analogues of biologically active molecules across multiple target classes will be discussed. In these studies, we have shown use of the tricyclic scaffold to synthesize potent inhibitors of the serine peptidase DPP-4, antagonists of the CCR5 receptor, and highly potent and selective PI3K δ isoform inhibitors. We also describe the predicted physicochemical properties of the resulting inhibitors and conclude that the tractable molecular scaffold could have potential application in future drug discovery programs.

  12. Four faces of the interaction between ions and aromatic rings.

    Science.gov (United States)

    Papp, Dóra; Rovó, Petra; Jákli, Imre; Császár, Attila G; Perczel, András

    2017-07-15

    Non-covalent interactions between ions and aromatic rings play an important role in the stabilization of macromolecular complexes; of particular interest are peptides and proteins containing aromatic side chains (Phe, Trp, and Tyr) interacting with negatively (Asp and Glu) and positively (Arg and Lys) charged amino acid residues. The structures of the ion-aromatic-ring complexes are the result of an interaction between the large quadrupole moment of the ring and the charge of the ion. Four attractive interaction types are proposed to be distinguished based on the position of the ion with respect to the plane of the ring: perpendicular cation-π (CP ⊥ ), co-planar cation-π (CP ∥ ), perpendicular anion-π (AP ⊥ ), and co-planar anion-π (AP ∥ ). To understand more than the basic features of these four interaction types, a systematic, high-level quantum chemical study is performed, using the X -  + C 6 H 6 , M +  + C 6 H 6 , X -  + C 6 F 6 , and M +  + C 6 F 6 model systems with X -  = H - , F - , Cl - , HCOO - , CH 3 COO - and M +  = H + , Li + , Na + , NH4+, CH 3 NH3+, whereby C 6 H 6 and C 6 F 6 represent an electron-rich and an electron-deficient π system, respectively. Benchmark-quality interaction energies with small uncertainties, obtained via the so-called focal-point analysis (FPA) technique, are reported for the four interaction types. The computations reveal that the interactions lead to significant stabilization, and that the interaction energy order, given in kcal mol -1 in parentheses, is CP ⊥ (23-37) > AP ⊥ (14-21) > CP ∥ (9-22) > AP ∥ (6-16). A natural bond orbital analysis performed leads to a deeper qualitative understanding of the four interaction types. To facilitate the future quantum chemical characterization of ion-aromatic-ring interactions in large biomolecules, the performance of three density functional theory methods, B3LYP, BHandHLYP, and M06-2X, is tested against the FPA benchmarks

  13. Iodine - catalyzed prins cyclization of aliphatic and aromatic ketones

    Energy Technology Data Exchange (ETDEWEB)

    Kishore, K.R.; Reddy, K.; Silva Junior, Luiz F., E-mail: luizfsjr@iq.usp.br [Universidade de Sao Paulo (IQ/USP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Fundamental

    2013-09-15

    Iodine-catalyzed Prins cyclization of homoallylic alcohols and ketones was investigated. Anhydrous conditions and inert atmosphere are not required in this metal-free protocol. The reaction of 2-(3,4-dihydronaphthalene-1-yl)propan-1-ol with six aliphatic symmetric ketones gave the desired products in 67-77% yield. Cyclization was performed with four aliphatic unsymmetric ketones, leading to corresponding pyrans in 66-76% yield. Prins cyclization was also accomplished with four aromatic ketones in 37-66% yield. Finally, Prins cyclization of the monoterpene isopulegol and acetone was successfully achieved. (author)

  14. Radiation-induced crosslinking of aromatic polymers with cardo group

    International Nuclear Information System (INIS)

    Xu Jun; Zhang Wanxi

    1991-01-01

    The effects of irradiation on the aromatic polymers with cardo group, such as polyetherketone with cardo group (PEK-C) and polyethersulfone with cardo group (PES-C) were studied. It was found that PEK-C and PES-C can be crosslinked by irradiation under vacuum. Moreover, it was also found that the intensity of the shake-up peak of X-ray photoelectron spectroscopy (XPS) for PEK-C and PES-C varies as irradiation dose. Gelation doses (Rg) of PEK-C and PES-C were estimated by shake-up peaks of XPS. (author) 6 refs.; 8 figs.; 3 tabs

  15. Preparation and Aromatic Hydrocarbon Removal Performance of Potassium Ferrate

    Directory of Open Access Journals (Sweden)

    Wei Guan

    2014-01-01

    Full Text Available This experiment adopts the hypochlorite oxidation method to constantly synthesize potassium ferrate. Under the condition of micropolluted source water pH and on the basis of naphthalene, phenanthrene, and pyrene as research objects, the effects of different systems to remove aromatic hydrocarbons were studied. Various oxidation systems to remove phenanthrene intermediate are analyzed and the detailed mechanisms for removal of phenanthrene are discussed. The study found that the main intermediate of potassium ferrate system to transform phenanthrene is 9,10-phenanthraquinone and its area percentage reached 82.66%; that is, 9,10-phenanthraquinone is the key entity to remove phenanthrene.

  16. Biodegradation Rates of Aromatic Contaminants in Biofilm Reactors

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1995-01-01

    compounds was typically controlled by first order kinetics. The first-order surface removal rate constants were surprisingly similar, ranging from 2 to 4 m/d. It appears that NSO-compounds inhibit the degradation of aromatic hydrocarbons, even at very low concentrations of NSO-compounds. Under nitrate......-reducing conditions, toluene was easily biodegraded. The xylenes and ethylbenzene were degraded cometabolically if toluene was used as a primary carbon source; their removal was influenced by competitive inhibition with toluene. These interaction phenomena are discussed in this paper and a kinetic model taking...

  17. Environmental polycyclic aromatic hydrocarbons affect androgen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Hnida, Christina; Larsen, John Christian

    2000-01-01

    Nine structurally different polycyclic aromatic hydrocarbons (PAHs) were tested for their ability to either agonize or antagonize the human androgen receptor (hAR) in a sensitive reporter gene assay based on CHO cells transiently cotransfected with a hAR vector and an MMTV-LUC vector. Benz......, determined in the presence of increasing concentrations of R1881. No cytotoxic effects of the tested compounds were observed as determined either by metabolic reduction using AlamarBlue (up to 20 mu M) or determined in cells transfected with a constitutively active hAR (up to 10 mu M). The well-known ability...

  18. Phenols and aromatic amines as thermal stabilizers in polyolefin processing

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Jan; Habicher, W. D.; Al-Malaika, S.; Zweifel, H.; Nešpůrek, Stanislav

    2001-01-01

    Roč. 176, - (2001), s. 55-63 ISSN 1022-1360. [International Conference on Polymer Modification, Degradation and Stabilization /1./. Palermo, 03.09.2000-07.09.2000] R&D Projects: GA AV ČR IAA1050901; GA MŠk ME 184; GA MŠk ME 372; GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : thermal stabilizers * phenols * aromatic amines Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.634, year: 2001

  19. Laboratory rotational spectroscopy of cyano substituted polycyclic aromatic hydrocarbons

    Science.gov (United States)

    McNaughton, Don; Jahn, Michaela K.; Travers, Michael J.; Wachsmuth, Dennis; Godfrey, Peter D.; Grabow, Jens-Uwe

    2018-03-01

    The rotational spectra of the four cyano substituted polycyclic aromatic hydrocarbon (PAH) molecules 1-cyanonaphthalene, 2-cyanonaphthalene, 9-cyanoanthracene and 9-cyanophenanthrene have been recorded in molecular expansions using a Stark modulated millimeterwave spectrometer and a Fourier Transform Microwave spectrometer in the cmwave region. The spectra have been assigned and fitted to provide molecular constants and quadrupole hyperfine constants of sufficient accuracy to enable complete hyperfine structure line predictions for interstellar searches. The data may provide a route into detection of small PAHs in the interstellar medium.

  20. Monitoring of nitropolycyclic aromatic hydrocarbons in food using gas chromatography.

    Science.gov (United States)

    Schlemitz, S; Pfannhauser, W

    1996-07-01

    Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) were determined in different kinds of food. The investigation of food matrices necessitates the development of appropriate analytical procedures for sensitive monitoring and determination of these compounds. The analysis of the nitro-PAHs was carried out by GC/MSD, GC plus mass spectrometry, and GC/NPD (nitrogen-phosphorus detection) GC plus nitrogen-phosphorus detection. Seven nitro-PAHs were positively identified and quantified in vegetables, smoked and grilled foods, oil, tea, coffee and spices.

  1. Measurement of polycyclic aromatic hydrocarbons and other pollutants.

    Science.gov (United States)

    Espigares García, M; Pérez López, J A; Mariscal Larrubia, A; Fernandez-Crehuet, M; Gálvez Vargas, R

    1987-04-01

    A single point study of atmospheric pollution has been carried out in Granada (Spain); suspended particulate matter, sulphur oxides, ammoniac, nitrogen dioxide and polycyclic aromatic hydrocarbons were determined. There were variations in relation to the month and the day of the week. The PAHs have been determined through HPLC, with a mobile phase of acetonitrile-water (75-25). The results of measurements of benzo(a)pyrene were between 1.006 and 0.485 micrograms m-3 in two different periods of sampling.

  2. Iodine - catalyzed prins cyclization of aliphatic and aromatic ketones

    International Nuclear Information System (INIS)

    Kishore, K.R.; Reddy, K.; Silva Junior, Luiz F.

    2013-01-01

    Iodine-catalyzed Prins cyclization of homoallylic alcohols and ketones was investigated. Anhydrous conditions and inert atmosphere are not required in this metal-free protocol. The reaction of 2-(3,4-dihydronaphthalene-1-yl)propan-1-ol with six aliphatic symmetric ketones gave the desired products in 67-77% yield. Cyclization was performed with four aliphatic unsymmetric ketones, leading to corresponding pyrans in 66-76% yield. Prins cyclization was also accomplished with four aromatic ketones in 37-66% yield. Finally, Prins cyclization of the monoterpene isopulegol and acetone was successfully achieved. (author)

  3. Extraction Techniques for Polycyclic Aromatic Hydrocarbons in Soils

    Directory of Open Access Journals (Sweden)

    E. V. Lau

    2010-01-01

    Full Text Available This paper aims to provide a review of the analytical extraction techniques for polycyclic aromatic hydrocarbons (PAHs in soils. The extraction technologies described here include Soxhlet extraction, ultrasonic and mechanical agitation, accelerated solvent extraction, supercritical and subcritical fluid extraction, microwave-assisted extraction, solid phase extraction and microextraction, thermal desorption and flash pyrolysis, as well as fluidised-bed extraction. The influencing factors in the extraction of PAHs from soil such as temperature, type of solvent, soil moisture, and other soil characteristics are also discussed. The paper concludes with a review of the models used to describe the kinetics of PAH desorption from soils during solvent extraction.

  4. Electrophilic Aromatic Substitution: New Insights into an Old Class of Reactions.

    Science.gov (United States)

    Galabov, Boris; Nalbantova, Didi; Schleyer, Paul von R; Schaefer, Henry F

    2016-06-21

    charge transfer from the benzene π system to the nitronium unit. In contrast to usual interpretations, our computational results provide compelling evidence that in nonpolar, noncomplexing media and in the absence of catalysts, the mechanism of aromatic sulfonation with sulfur trioxide is concerted and does not involve the conventional σ-complex (Wheland) intermediates. Stable under such conditions, (SO3)2 dimers react with benzene much more readily than monomeric sulfur trioxide. In polar (complexing) media, the reaction follows the classic two-stage SEAr mechanism. Still, the rate-controlling transition state involves two SO3 molecules. The reactivity and regioselectivity in EAS reactions that follow the classic mechanistic scheme are quantified using a theoretically evaluated quantity, the electrophile affinity (Eα), which measures the stabilization energy associated with the formation of arenium ions. Examples of applications are provided.

  5. Electrodegradation of Ponceau 2R using dimensionally-stable anodes and Ti/Pt

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Francisco Wirley Paulino; Oliveira, Sameque do Nascimento; Lima-Neto, Pedro de; Correia, Adriana Nunes, E-mail: adriana@ufc.br [Universidade Federal do Ceara, Fortaleza (UFC), CE (Brazil). Centro de Ciencias. Dept. de Quimica Analitica e Fisico-Quimica; Mascaro, Lucia Helena; Matos, Roberto de; Souza, Ernesto Chaves Pereira de [Universidade Federal de Sao Carlos (UFSC), SP (Brazil). Dept. de Quimica; Lanza, Marcos Roberto de Vasconcelos [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica

    2013-08-01

    This paper reports the electrochemical degradation of the azo dye Ponceau 2R under galvanostatic electrolysis in the 1 to 200 mA cm{sup -2} range at room temperature using dimensionally-stable anodes of oxygen (DSA-O{sub 2}), chlorine (DSA-Cl{sub 2}) and a titanium electrode of platinum coated with platinum oxide (Ti/Pt). The methodology applied was efficient for removing the color of the Ponceau 2R and the highest percentage removal of total organic carbon was obtained at 200 mA cm{sup -2}. Despite not having been observed complete mineralization, approximately 80% removal of aromatic rings was estimated, resulting in drastic reduction of toxicity of the sample. (author)

  6. The effects of early diagenesis on the chemical and stable carbon isotopic composition of wood

    International Nuclear Information System (INIS)

    Spiker, E.C.; Hatcher, P.G.

    1987-01-01

    Studies of modern and ancient buried wood show that there is a linear correlation between carbohydrate content and the stable carbon isotope composition as carbohydrates are preferentially degraded during early diagenesis. As the carbohydrate content decreases, the delta 13 C value of the degraded wood decreases 1 to 2 per mil, approaching the value of the residual lignin. These results indicate that carbohydrate degradation products are lost and not incorporated into the aromatic structure as lignin is selectively preserved during early diagenesis of wood. These results also indicate that attempts to quantify terrestrial inputs to modern sedimentary organic matter based on delta 13 C values should consider the possibility of a 1 to 2 per mil decrease in the delta 13 C value of degraded wood. (author)

  7. Thermally stable dexsil-400 glass capillary columns

    International Nuclear Information System (INIS)

    Maskarinec, M.P.; Olerich, G.

    1980-01-01

    The factors affecting efficiency, thermal stability, and reproducibility of Dexsil-400 glass capillary columns for gas chromatography in general, and for polycyclic aromatic hydrocarbons (PAHs) in particular were investigated. Columns were drawn from Kimble KG-6 (soda-lime) glass or Kimox (borosilicate) glass. All silylation was carried out at 200 0 C. Columns were coated according to the static method. Freshly prepared, degassed solutions of Dexsil-400 in pentane or methylene chloride were used. Thermal stability of the Dexsil 400 columns with respect to gas chromatography/mass spectrometry (GC/MS) were tested. Column-to-column variability is a function of each step in the fabrication of the columns. The degree of etching, extent of silylation, and stationary phase film thickness must be carefully controlled. The variability in two Dexsil-400 capillary column prepared by etching, silylation with solution of hexa methyl disilazone (HMDS), and static coating is shown and also indicates the excellent selectivity of Dexsil-400 for the separation of alkylated aromatic compounds. The wide temperature range of Dexsil-400 and the high efficiency of the capillary columns also allow the analysis of complex mixtures with minimal prefractionation. Direct injection of a coal liquefaction product is given. Analysis by GC/MS indicated the presence of parent PAHs, alkylated PAHs, nitrogen and sulfur heterocycles, and their alkylated derivatives. 4 figures

  8. Space Environmentally Stable Polyimides and Copolyimides

    Science.gov (United States)

    Watson, Kent A.; Connell, John W.

    2000-01-01

    Polyimides with a unique combination of properties including low color in thin films, atomic oxygen (AO), ultra-violet (UV) radiation resistance, solubility in organic solvents in the imide form, high glass transition (T(sub g)) temperatures and high thermal stability have been prepared and characterized. The polymers were prepared by reacting a novel aromatic diamine with aromatic dianhydrides in a polar aprotic solvent. The solubility of the polymers in the imide form as well as the color density of thin films were dependent upon the chemical structure of the dianhydride. Several thin films (25-50 mm thick) prepared by solution casting of amide acid or imide solutions exhibited very low color and high optical transparency (approximately 90%) as determined by UV/visible spectroscopy. The polymers exhibited T(sub g)s >200 C depending upon the structure of the dianhydride and temperatures of 5% weight loss approximately 500C in air as determined by dynamic thermogravimetric analysis. Thin films coated with silver/inconel were exposed to a high fluence of AO and 1000 equivalent solar hours of UV radiation. The effects of these exposures on optical properties were minor. These space environmentally durable polymers are potentially useful in a variety of applications on spacecraft such as thin film membranes on antennas, second-surface mirrors, thermal/optical coatings and multi-layer thermal insulation (MLI) blanket materials. The chemistry, physical and mechanical properties of the polymers as well as their responses to AO and UV exposure will be discussed.

  9. Stable Isotope Group 1983 progress report

    International Nuclear Information System (INIS)

    Stewart, M.K.

    1984-06-01

    The work of the Stable Isotope Group of the Institute of Nuclear Sciences in the fields of isotope geology, isotope hydrology, geochronology, isotope biology and related fields, and mass spectrometer instrumentation, during 1983, is described

  10. Stable Isotope Group 1982 progress report

    International Nuclear Information System (INIS)

    Stewart, M.K.

    1983-06-01

    The work of the Stable Isotope Group of the Institute of Nuclear Sciences during 1982, in the fields of isotope geology, isotope hydrology, geochronology, isotope biology and mass spectrometer instrumentation, is described

  11. Bartolome Island, Galapagos Stable Oxygen Calibration Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Galapagos Coral Stable Oxygen Calibration Data. Sites: Bartolome Island: 0 deg, 17'S, 90 deg 33' W. Champion Island: 1 deg, 15'S, 90 deg, 05' W. Urvina Bay (Isabela...

  12. Allan Hills Stable Water Isotopes, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes stable water isotope values at 10 m resolution along an approximately 5 km transect through the main icefield of the Allan Hills Blue Ice...

  13. Applications of stable isotopes in clinical pharmacology

    Science.gov (United States)

    Schellekens, Reinout C A; Stellaard, Frans; Woerdenbag, Herman J; Frijlink, Henderik W; Kosterink, Jos G W

    2011-01-01

    This review aims to present an overview of the application of stable isotope technology in clinical pharmacology. Three main categories of stable isotope technology can be distinguished in clinical pharmacology. Firstly, it is applied in the assessment of drug pharmacology to determine the pharmacokinetic profile or mode of action of a drug substance. Secondly, stable isotopes may be used for the assessment of drug products or drug delivery systems by determination of parameters such as the bioavailability or the release profile. Thirdly, patients may be assessed in relation to patient-specific drug treatment; this concept is often called personalized medicine. In this article, the application of stable isotope technology in the aforementioned three areas is reviewed, with emphasis on developments over the past 25 years. The applications are illustrated with examples from clinical studies in humans. PMID:21801197

  14. Tannaka duality and stable infinity-categories

    OpenAIRE

    Iwanari, Isamu

    2014-01-01

    We introduce the notion of fine tannakian infinity-categories and prove Tannaka duality results for symmetric monoidal stable infinity-categories over a field of characteristic zero. We also discuss several examples.

  15. On Stable Marriages and Greedy Matchings

    Energy Technology Data Exchange (ETDEWEB)

    Manne, Fredrik; Naim, Md; Lerring, Hakon; Halappanavar, Mahantesh

    2016-12-11

    Research on stable marriage problems has a long and mathematically rigorous history, while that of exploiting greedy matchings in combinatorial scientific computing is a younger and less developed research field. In this paper we consider the relationships between these two areas. In particular we show that several problems related to computing greedy matchings can be formulated as stable marriage problems and as a consequence several recently proposed algorithms for computing greedy matchings are in fact special cases of well known algorithms for the stable marriage problem. However, in terms of implementations and practical scalable solutions on modern hardware, the greedy matching community has made considerable progress. We show that due to the strong relationship between these two fields many of these results are also applicable for solving stable marriage problems.

  16. Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polycyclic Aromatic Compounds in Titan's Atmosphere, the Interstellar Medium and Combustion

    Science.gov (United States)

    Landera, Alexander

    2013-12-01

    Several different mechanisms leading to the formation of (substituted) naphthalene and azanaphthalenes were examined using theoretical quantum chemical calculations. As a result, a series of novel synthetic routes to Polycyclic Aromatic Hydrocarbons (PAHs) and Nitrogen Containing Polycyclic Aromatic Compounds (N-PACs) have been proposed. On Earth, these aromatic compounds originate from incomplete combustion and are released into our environment, where they are known to be major pollutants, often with carcinogenic properties. In the atmosphere of a Saturn's moon Titan, these PAH and N-PACs are believed to play a critical role in organic haze formation, as well as acting as chemical precursors to biologically relevant molecules. The theoretical calculations were performed by employing the ab initio G3(MP2,CC)/B3LYP/6-311G** method to effectively probe the Potential Energy Surfaces (PES) relevant to the PAH and N-PAC formation. Following the construction of the PES, Rice-Ramsperger-Kassel-Markus (RRKM) theory was used to evaluate all unimolecular rate constants as a function of collision energy under single-collision conditions. Branching ratios were then evaluated by solving phenomenological rate expressions for the various product concentrations. The most viable pathways to PAH and N-PAC formation were found to be those where the initial attack by the ethynyl (C2H) or cyano (CN) radical toward a unsaturated hydrocarbon molecule led to the formation of an intermediate which could not effectively lose a hydrogen atom. It is not until ring cyclization has occurred, that hydrogen elimination leads to a closed shell product. By quenching the possibility of the initial hydrogen atom elimination, one of the most competitive processes preventing the PAH or N-PAC formation was avoided, and the PAH or N-PAC formation was allowed to proceed. It is concluded that these considerations should be taken into account when attempting to explore any other potential routes towards

  17. The Reactivity of Stable Metallacyclobutenes and Vinylcarbenes

    OpenAIRE

    Holland, Ryan Lynn

    2016-01-01

    Chapter 1. Historical Development of Stable Metallacyclobutenes Fred Tebbe and co-workers synthesized the first stable metallacyclobutene complexes in the late 1970’s by treatment of an intermediate titanium methylene species – later popularized as the “Tebbe reagent” – with acetylenes. Robert Grubbs at Caltech further studied this system, using it to detail a degenerate metathesis reaction and to isolate a metallacyclobutane complex – which was implicated in the emerging field of alkene meta...

  18. Stable atomic hydrogen: Polarized atomic beam source

    International Nuclear Information System (INIS)

    Niinikoski, T.O.; Penttilae, S.; Rieubland, J.M.; Rijllart, A.

    1984-01-01

    We have carried out experiments with stable atomic hydrogen with a view to possible applications in polarized targets or polarized atomic beam sources. Recent results from the stabilization apparatus are described. The first stable atomic hydrogen beam source based on the microwave extraction method (which is being tested ) is presented. The effect of the stabilized hydrogen gas density on the properties of the source is discussed. (orig.)

  19. Biomass accumulation and energy conversion efficiency in aromatic rice genotypes.

    Science.gov (United States)

    Shahidullah, S M; Hanafi, M M; Ashrafuzzaman, M; Razi Ismail, M; Salam, M A; Khair, A

    2010-01-01

    A field experiment was conducted to evaluate photosynthetic efficiency along with different growth parameters of aromatic rice genotypes. Forty genotypes including three non-aromatic checks exhibited enormous variations for leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR), grain yield, total dry matter, harvest index and photosynthetic efficiency or energy use efficiency (Emu) at panicle initiation and heading stages. Minimum LAI-value was 0.52 in Khazar at PI stage and maximum was 4.91 in Sakkor khora at heading stage. The CGR-value was in the range of 4.80-24.11 g m(-2) per day. The best yielder BR39 produced grain of 4.21 t ha(-1) and the worst yielder Khazar gave 1.42 t ha(-1). Total dry matter (TDM) yield varied from 4.04 to 12.26 t ha(-1) where genotypes proved their energy use efficiency a range between 0.58 to 1.65%. Emu showed a significant positive relation with TDM (r=0.80(**)), CGR (r=0.72(**)) and grain yield (r=0.66(**)). A negative correlation was established between TDM and harvest index and LAI and RGR. Path analysis result showed that NAR at heading stage exerted highest positive direct effect (0.70) on Emu. Copyright 2009 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  20. Control of aromatic-waste air streams by soil bioreactors

    International Nuclear Information System (INIS)

    Miller, D.E.; Canter, L.W.

    1991-01-01

    Contamination of groundwater resources is a serious environmental problem which is continuing to increase in occurrence in the United States. It has been reported that leaking underground gasoline storage tanks may pose the most serious threat of all sources of groundwater contamination. Gasolines are comprised of a variety of aliphatic and aromatic hydrocarbons. The aromatic portion consists primarily of benzene, toluene, ethylbenzene, and xylenes (BTEX compounds). BTEX compounds are also among the most frequency identified substances at Superfund sites. Pump and treat well systems are the most common and frequently used technique for aquifer restoration. Treatment is often in the form of air stripping to remove the volatile components from the contaminated water. Additionally, soil ventilation processes have been used to remove volatile components from the vadose zone. Both air stripping and soil ventilation produce a waste gas stream containing volatile compounds which is normally treated by carbon adsorption or incineration. Both treatment processes require a substantial capital investment and continual operation and maintenance expenditures. The objective of the study was to examine the potential of using soil bioreactors to treat a waste gas stream produced by air stripping or soil ventilation process. Previous studies have shown that various hydrocarbons can be successfully treated with soils. The study examined the removal of BTEX compounds within soil columns and the influence of soil type, inlet concentration, and inlet flow rate on the removal efficiency