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Sample records for abiotic organic synthesis

  1. Pathways for abiotic organic synthesis at submarine hydrothermal fields.

    Science.gov (United States)

    McDermott, Jill M; Seewald, Jeffrey S; German, Christopher R; Sylva, Sean P

    2015-06-23

    Arguments for an abiotic origin of low-molecular weight organic compounds in deep-sea hot springs are compelling owing to implications for the sustenance of deep biosphere microbial communities and their potential role in the origin of life. Theory predicts that warm H2-rich fluids, like those emanating from serpentinizing hydrothermal systems, create a favorable thermodynamic drive for the abiotic generation of organic compounds from inorganic precursors. Here, we constrain two distinct reaction pathways for abiotic organic synthesis in the natural environment at the Von Damm hydrothermal field and delineate spatially where inorganic carbon is converted into bioavailable reduced carbon. We reveal that carbon transformation reactions in a single system can progress over hours, days, and up to thousands of years. Previous studies have suggested that CH4 and higher hydrocarbons in ultramafic hydrothermal systems were dependent on H2 generation during active serpentinization. Rather, our results indicate that CH4 found in vent fluids is formed in H2-rich fluid inclusions, and higher n-alkanes may likely be derived from the same source. This finding implies that, in contrast with current paradigms, these compounds may form independently of actively circulating serpentinizing fluids in ultramafic-influenced systems. Conversely, widespread production of formate by ΣCO2 reduction at Von Damm occurs rapidly during shallow subsurface mixing of the same fluids, which may support anaerobic methanogenesis. Our finding of abiogenic formate in deep-sea hot springs has significant implications for microbial life strategies in the present-day deep biosphere as well as early life on Earth and beyond.

  2. Abiotic synthesis of organic compounds from carbon disulfide under hydrothermal conditions.

    Science.gov (United States)

    Rushdi, Ahmed I; Simoneit, Bernd R T

    2005-12-01

    Abiotic formation of organic compounds under hydrothermal conditions is of interest to bio, geo-, and cosmochemists. Oceanic sulfur-rich hydrothermal systems have been proposed as settings for the abiotic synthesis of organic compounds. Carbon disulfide is a common component of magmatic and hot spring gases, and is present in marine and terrestrial hydrothermal systems. Thus, its reactivity should be considered as another carbon source in addition to carbon dioxide in reductive aqueous thermosynthesis. We have examined the formation of organic compounds in aqueous solutions of carbon disulfide and oxalic acid at 175 degrees C for 5 and 72 h. The synthesis products from carbon disulfide in acidic aqueous solutions yielded a series of organic sulfur compounds. The major compounds after 5 h of reaction included dimethyl polysulfides (54.5%), methyl perthioacetate (27.6%), dimethyl trithiocarbonate (6.8%), trithianes (2.7%), hexathiepane (1.4%), trithiolanes (0.8%), and trithiacycloheptanes (0.3%). The main compounds after 72 h of reaction consisted of trithiacycloheptanes (39.4%), pentathiepane (11.6%), tetrathiocyclooctanes (11.5%), trithiolanes (10.6%), tetrathianes (4.4%), trithianes (1.2%), dimethyl trisulfide (1.1%), and numerous minor compounds. It is concluded that the abiotic formation of aliphatic straight-chain and cyclic polysulfides is possible under hydrothermal conditions and warrants further studies.

  3. Reduction of nitrogen compounds in oceanic basement and its implications for HCN formation and abiotic organic synthesis.

    Science.gov (United States)

    Holm, Nils G; Neubeck, Anna

    2009-10-22

    Hydrogen cyanide is an excellent organic reagent and is central to most of the reaction pathways leading to abiotic formation of simple organic compounds containing nitrogen, such as amino acids, purines and pyrimidines. Reduced carbon and nitrogen precursor compounds for the synthesis of HCN may be formed under off-axis hydrothermal conditions in oceanic lithosphere in the presence of native Fe and Ni and are adsorbed on authigenic layer silicates and zeolites. The native metals as well as the molecular hydrogen reducing CO2 to CO/CH4 and NO3-/NO2- to NH3/NH4+ are a result of serpentinization of mafic rocks. Oceanic plates are conveyor belts of reduced carbon and nitrogen compounds from the off-axis hydrothermal environments to the subduction zones, where compaction, dehydration, desiccation and diagenetic reactions affect the organic precursors. CO/CH4 and NH3/NH4+ in fluids distilled out of layer silicates and zeolites in the subducting plate at an early stage of subduction will react upon heating and form HCN, which is then available for further organic reactions to, for instance, carbohydrates, nucleosides or even nucleotides, under alkaline conditions in hydrated mantle rocks of the overriding plate. Convergent margins in the initial phase of subduction must, therefore, be considered the most potent sites for prebiotic reactions on Earth. This means that origin of life processes are, perhaps, only possible on planets where some kind of plate tectonics occur.

  4. Reduction of nitrogen compounds in oceanic basement and its implications for HCN formation and abiotic organic synthesis

    Directory of Open Access Journals (Sweden)

    Neubeck Anna

    2009-10-01

    Full Text Available Abstract Hydrogen cyanide is an excellent organic reagent and is central to most of the reaction pathways leading to abiotic formation of simple organic compounds containing nitrogen, such as amino acids, purines and pyrimidines. Reduced carbon and nitrogen precursor compounds for the synthesis of HCN may be formed under off-axis hydrothermal conditions in oceanic lithosphere in the presence of native Fe and Ni and are adsorbed on authigenic layer silicates and zeolites. The native metals as well as the molecular hydrogen reducing CO2 to CO/CH4 and NO3-/NO2- to NH3/NH4+ are a result of serpentinization of mafic rocks. Oceanic plates are conveyor belts of reduced carbon and nitrogen compounds from the off-axis hydrothermal environments to the subduction zones, where compaction, dehydration, desiccation and diagenetic reactions affect the organic precursors. CO/CH4 and NH3/NH4+ in fluids distilled out of layer silicates and zeolites in the subducting plate at an early stage of subduction will react upon heating and form HCN, which is then available for further organic reactions to, for instance, carbohydrates, nucleosides or even nucleotides, under alkaline conditions in hydrated mantle rocks of the overriding plate. Convergent margins in the initial phase of subduction must, therefore, be considered the most potent sites for prebiotic reactions on Earth. This means that origin of life processes are, perhaps, only possible on planets where some kind of plate tectonics occur.

  5. Organic synthesis

    International Nuclear Information System (INIS)

    Lallemand, J.Y.; Fetizon, M.

    1988-01-01

    The 1988 progress report of the Organic Synthesis Chemistry laboratory (Polytechnic School, France), is presented. The laboratory activities are centered on the chemistry of natural products, which have a biological activity and on the development of new reactions, useful in the organic synthesis. The research works involve the following domains: the natural products chemistry which are applied in pharmacology, the plants and insects chemistry, the organic synthesis, the radical chemistry new reactions and the bio-organic physicochemistry. The published papers, the congress communications and the thesis are listed [fr

  6. Organic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S.E.

    1991-01-01

    This paper reports on reactions of organoboranes. Organoboron routes to unsaturated hydrocarbons. Boronic ester homologation. Properties of organosilicon compounds. Alkene synthesis (Peterson olefination). Allylsilanes and acylsilanes.

  7. Experimental Evidence for Abiotic Sulfurization of Marine Dissolved Organic Matter

    Directory of Open Access Journals (Sweden)

    Anika M. Pohlabeln

    2017-11-01

    Full Text Available Dissolved organic sulfur (DOS is the largest pool of organic sulfur in the oceans, and as such it is an important component of the global sulfur cycle. DOS in the ocean is resistant against microbial degradation and turns over on a millennium time scale. However, sources and mechanisms behind its stability are largely unknown. Here, we hypothesize that in sulfate-reducing sediments sulfur is abiotically incorporated into dissolved organic matter (DOM and released to the ocean. We exposed natural seawater and the filtrate of a plankton culture to sulfidic conditions. Already after 1-h at 20°C, DOS concentrations had increased 4-fold in these experiments, and 14-fold after 4 weeks at 50°C, indicating that organic matter does not need long residence times in natural sulfidic environments to be affected by sulfurization. Molecular analysis via ultrahigh-resolution mass spectrometry showed that sulfur was covalently and unselectively bound to DOM. Experimentally produced and natural DOS from sediments were highly similar on a molecular and structural level. By combining our data with published benthic DOC fluxes we estimate that 30–200 Tg DOS are annually transported from anaerobic and sulfate reducing sediments to the oceans. Uncertainties in this first speculative assessment are large. However, this first attempt illustrates that benthic DOS flux is potentially one order of magnitude larger than that via rivers indicating that this could balance the estimated global net removal of refractory DOS.

  8. Abiotic condensation synthesis of glyceride lipids and wax esters under simulated hydrothermal conditions.

    Science.gov (United States)

    Rushdi, Ahmed I; Simoneit, Bernd R T

    2006-04-01

    Precursor compounds for abiotic proto cellular membranes are necessary for the origin of life. Amphipathic compounds such as fatty acids and acyl glycerols are important candidates for micelle/bilayer/vesicle formation. Two sets of experiments were conducted to study dehydration reactions of model lipid precursors in aqueous media to form acyl polyols and wax esters, and to evaluate the stability and reactions of the products at elevated temperatures. In the first set, mixtures of n-nonadecanoic acid and ethylene glycol in water, with and without oxalic acid, were heated at discrete temperatures from 150 ( composite function)C to 300 ( composite function)C for 72 h. The products were typically alkyl alkanoates, ethylene glycolyl alkanoates, ethylene glycolyl bis-alkanoates and alkanols. The condensation products had maximum yields between 150 ( composite function)C and 250 ( composite function)C, and were detectable and thus stable under hydrothermal conditions to temperatures acid and glycerol were heated using the same experimental conditions, with and without oxalic acid, between 100 ( composite function)C and 250 ( composite function)C. The main condensation products were two isomers each of monoacylglycerols and diacylglycerols at all temperatures, as well as minor amounts of the fatty acid anhydride and methyl ester. The yield of glyceryl monoheptanoates generally increased with increasing temperature and glyceryl diheptanoates decreased noticeably with increasing temperature. The results indicate that condensation reactions and abiotic synthesis of organic lipid compounds under hydrothermal conditions occur easily, provided precursor concentrations are sufficiently high.

  9. Abiotic Synthesis of Nucleic Acids: Hypochromicity and Future Research

    Science.gov (United States)

    Glass, K.; Oye, M.; Deamer, D.; Vercoutere, W.

    2017-01-01

    The earliest forms of life would likely have a protocellular form, with a membrane encapsulating some form of linear charged polymer. These polymers could have enzymatic as well as genetic properties. We can simulate plausible prebiotic conditions in the laboratory to test hypotheses related to this concept. In earlier work we have shown that mononucleotides organized within a multilamellar lipid matrix can produce oligomers in the anhydrous phase of dehydration- rehydration cycles (Rajamani, 2008). If mononucleotides are in solution at millimolar concentrations, then oligomers resembling RNA are synthesized and exist in a steady state with their monomers DeGuzman, 2014). We have used conventional and novel techniques to demonstrate that secondary structures stabilized by hydrogen bonds may be present in the condensation products produced in dehydration- rehydration cycles that simulate hydrothermal fields that were present on the early Earth. Gel electrophoresis data corroborates the presence of up to 200-base pair length RNA fragments in products of Hydration-Dehydration experiments. Furthermore, hypochromicity measurements demonstrate a degree of hypochromicity found in single RNA strand of known sequence, as well as results that indicate this is true also for a sample of complementary strands of RNA. Analysis of ionic current signatures of known RNA hairpin molecule as measured using a nanopore detector indicate a significant variability in pattern, different from the signatures produced by DNA hairpin molecules. This informs how we may interpret nanopore data gathered from prebiotic simulations.

  10. MICROWAVES IN ORGANIC SYNTHESIS

    Science.gov (United States)

    The effect of microwaves, a non-ionizing radiation, on organic reactions is described both in polar solvents and under solvent-free conditions. The special applications are highlighted in the context of solventless organic synthesis which involve microwave (MW) exposure of neat r...

  11. Abiotic synthesis of porphyrins and other oligopyrroles on the early Earth and Earth-like planets

    Science.gov (United States)

    Fox, S.; Strasdeit, H.

    2013-09-01

    It is generally accepted that abiotically formed amino acids existed on Earth in the late Hadean and early Archean (four billion years ago). They were mainly dissolved in a salty primordial ocean. At that time, volcanic islands were much more abundant than today. It is therefore reasonable to assume that, at hot volcanic coasts, amino acids could have been thermally transformed into other organic molecules. Based on this scenario, we conducted laboratory experiments that simulated the interaction between amino acid-containing sea water and hot lava. In these experiments, a large number of different volatile products were formed, among them pyrroles. It was also possible to obtain porphyrins and other oligopyrroles from pyrroles under simulated conditions of primordial volcanic islands. All experiments were conducted under plausible prebiotic conditions. Our results reveal an abiotic pathway to possible precursors of oligopyrrole-type biomolecules, such as heme and chlorophylls.

  12. Comparison of bacterial cells and amine-functionalized abiotic surfaces as support for Pd nanoparticle synthesis

    DEFF Research Database (Denmark)

    De Corte, Simon; Bechstein, Stefanie; Lokanathan, Arcot R.

    2013-01-01

    An increasing demand for catalytic Pd nanoparticles has motivated the search for sustainable production methods. An innovative approach uses bacterial cells as support material for synthesizing Pd nanoparticles by reduction of Pd(II) with e.g. hydrogen or formate. Nevertheless, drawbacks...... nanoparticles, and that abiotic surfaces could support the Pd particle synthesis as efficiently as bacteria. In this study, we explore the possibility of replacing bacteria with amine-functionalized materials, and we compare different functionalization strategies. Pd nanoparticles formed on the support...... on these surfaces was higher than for Pd particles formed on Shewanella oneidensis cells. Smaller Pd nanoparticles generally have better catalytic properties, and previous studies have shown that the particle size can be lowered by increasing the amount of support material used during Pd particle formation. However...

  13. Study of organic chlorine in soils and formation in biotic and abiotic conditions

    International Nuclear Information System (INIS)

    Osswald, Aurelie

    2016-01-01

    Chlorine has long been considered as the predominantly chlorine form present in the environment. However, recent studies have shown that chlorine is retained in the soil as an organic form and is formed by a natural process of chlorination mainly from the microbial activity of the soil still poorly documented. The aim of this study is to estimate the organic and inorganic forms of chlorine in contrasting soil and highlight the evolution of these forms according to certain environmental parameters or terms of incubations and to the activity of microorganisms. For this, the organo-mineral horizons of contrasting soil were studied (i) in situ: The amounts of chlorine and physico-chemical and microbiological parameters of soil were measured; (ii) in two experimental devices incubations under different conditions. Measurements of chlorine levels between the beginning and the end of the first experiment were measured by AOX analyzer. For the second experiment, the soil was previously enriched with Na 37 Cl and 37 Cl levels were measured by HR ICP MS. Soil samples from these incubations were analyzed by Xanes spectrometry to identify the speciation of chlorine forms in soils. Soil non-extractable organic chlorine contents represent almost all of the chlorine. The parameters that influence the distribution of chlorine contents in soils correspond to vegetation cover, pH, organic carbon content and quantities of microorganisms. The chlorine contents measured by AOX analyzer and by HR ICP MS highlight an organic chlorine formation over time in relation to the microorganisms in the soil. The measures carried out by HR ICP MS show also an organic chlorine formation in abiotic conditions. Conversely, XANES spectrometry measurements have shown any organic chlorine formation. In conclusion, the parameters that influence the distribution of chlorine contents in soils have been targeted. Similarly, the microbial origin of the chlorination process has been demonstrated, although a

  14. Salt lakes of Western Australia - Natural abiotic formation of volatile organic compounds

    Science.gov (United States)

    Krause, T.; Studenroth, S.; Mulder, I.; Tubbesing, C.; Kotte, K.; Ofner, J.; Junkermann, W.; Schöler, H. F.

    2012-04-01

    Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many ephemeral saline and hypersaline lakes with a wide range of hydrogeochemical parameters that have gradually changed over the last fifty years. Historically, the region was covered by eucalyptus trees and shrubs, but was cleared mainly within 10 years after WWII to make room for wheat and live stock. After the clearance of the deep rooted native plants the groundwater started to rise, bringing increased amounts of dissolved salts and minerals to the surface and discharging them into streams and lakes. Thus most of Western Australia is influenced by secondary salinisation (soil salting) [1]. Another problem is that the discharged minerals affect the pH of ground and surface water, which ranges from acidic to slightly basic. During the 2011 campaign surface water was measured with a pH between 2.5 and 7.1. Another phenomenon in Western Australia is the decrease of rainfall over the last decades assumed to be linked to the secondary salinisation. The rising saline and mineral rich groundwater increases the biotical and abiotical activity of the salt lakes. Halogenated and non-halogenated volatile organic compounds emitted from those lakes undergo fast oxidation and chemical reactions to form small particles modifying cloud microphysics and thus suppressing rain events [2]. Our objective is to gain a better understanding of this extreme environment with its hypersaline acidic lakes with regard to the potential abiotic formation of volatile organic compounds and its impact on the local climate. In spring 2011 fifty-three sediment samples from ten salt lakes in the Lake King region where taken, freeze-dried and ground. In order to simulate the abiotic formation of volatile organic compounds the soil samples were resuspended with water in gas-tight headspace vials. The headspace was measured using a purge and trap GC

  15. Abiotic stressors and stress responses: What commonalities appear between species across biological organization levels?

    International Nuclear Information System (INIS)

    Sulmon, Cécile; Baaren, Joan van; Cabello-Hurtado, Francisco; Gouesbet, Gwenola; Hennion, Françoise; Mony, Cendrine; Renault, David; Bormans, Myriam; El Amrani, Abdelhak; Wiegand, Claudia; Gérard, Claudia

    2015-01-01

    Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), we review how organisms respond and adapt to chemical- and temperature-induced stresses from molecular to population level. Using field-realistic studies, our integrative analysis aims to compare i) how molecular and physiological mechanisms related to protection, repair and energy allocation can impact life history traits of stressed organisms, and ii) to what extent trait responses influence individual and population responses. Common response mechanisms are evident at molecular and cellular scales but become rather difficult to define at higher levels due to evolutionary distance and environmental complexity. We provide new insights into the understanding of the impact of molecular and cellular responses on individual and population dynamics and assess the potential related effects on communities and ecosystem functioning. - Highlights: • Responses to chemical and thermal stressors are reviewed across organization levels. • Common responses between taxa are evident at the molecular and cellular scales. • At individual level, energy allocation connects species-specific stress responses. • Commonality decreases at higher levels due to increasing environmental complexity. - The commonality of stress responses to chemical and thermal stressors among taxa is evident at the molecular and cellular scales but remains unclear at higher levels of organization

  16. Persistent Organic Pollutants in Biotic and Abiotic Components of Antarctic Pristine Environment

    Science.gov (United States)

    Bhardwaj, Laxmikant; Chauhan, Abhishek; Ranjan, Anuj; Jindal, Tanu

    2018-05-01

    Over the past decades, research in Antarctica has built a new understanding of Antarctica, its past, present and future. Human activities and long-range pollutants are increasing on the Antarctic continent. Research on persistent organic pollutants (POPs) has been carried out internationally by several countries having their permanent research stations to explain the impact of an ever increasing range of POPs in Antarctic ecosystem. POPs have been detected in Antarctica despite its geographical isolation and almost complete absence of human settlements. The presence of POPs in different abiotic (atmosphere, water bodies, sediments, soil, sea ice) and biotic components (mosses, lichens, krill, penguins, skua, etc.) in Antarctica has been studied and documented around for decades and has either been banned or strictly regulated but is still found in the environment. This review focuses on recent research pertaining to sources and occurrence of POPs in Antarctic lake water, soil, sediment, lichen, mosses and other Antarctic marine community. This review also proposes to summarize the current state of research on POPs in Antarctica environment and draw the earliest conclusions on possible significance of POPs in Antarctica based on presently available information from related Antarctic environment.

  17. Mud, Macrofauna and Microbes: An ode to benthic organism-abiotic interactions at varying scales

    Science.gov (United States)

    Benthic environments are dynamic habitats, subject to variable sources and rates of sediment delivery, reworking from the abiotic and biotic processes, and complex biogeochemistry. These activities do not occur in a vacuum, and interact synergistically to influence food webs, bi...

  18. ABA and GA3 regulate the synthesis of primary and secondary metabolites related to alleviation from biotic and abiotic stresses in grapevine.

    Science.gov (United States)

    Murcia, Germán; Fontana, Ariel; Pontin, Mariela; Baraldi, Rita; Bertazza, Gianpaolo; Piccoli, Patricia N

    2017-03-01

    Plants are able to synthesize a large number of organic compounds. Among them, primary metabolites are known to participate in plant growth and development, whereas secondary metabolites are mostly involved in defense and other facultative processes. In grapevine, one of the major fruit crops in the world, secondary metabolites, mainly polyphenols, are of great interest for the wine industry. Even though there is an extensive literature on the content and profile of those compounds in berries, scarce or no information is available regarding polyphenols in other organs. In addition, little is known about the effect of plant growth regulators (PGRs), ABA and GA 3 (extensively used in table grapes) on the synthesis of primary and secondary metabolites in wine grapes. In table grapes, cultural practices include the use of GA 3 sprays shortly before veraison, to increase berry and bunch size, and sugar content in fruits. Meanwhile, ABA applications to the berries on pre-veraison improve the skin coloring and sugar accumulation, anticipating the onset of veraison. Accordingly, the aim of this study was to assess and characterize primary and secondary metabolites in leaves, berries and roots of grapevine plants cv. Malbec at veraison, and changes in compositions after ABA and GA 3 aerial sprayings. Metabolic profiling was conducted using GC-MS, GC-FID and HPLC-MWD. A large set of metabolites was identified: sugars, alditols, organic acids, amino acids, polyphenols (flavonoids and non-flavonoids) and terpenes (mono-, sesqui-, di- and triterpenes). The obtained results showed that ABA applications elicited synthesis of mono- and sesquiterpenes in all assessed tissues, as well as L-proline, acidic amino acids and anthocyanins in leaves. Additionally, applications with GA 3 elicited synthesis of L-proline in berries, and mono- and sesquiterpenes in all the tissues. However, treatment with GA 3 seemed to block polyphenol synthesis, mainly in berries. In conclusion, ABA and GA

  19. 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

  20. Abiotic synthesis of purines and other heterocyclic compounds by the action of electrical discharges

    Science.gov (United States)

    Yuasa, S.; Flory, D.; Basile, B.; Oro, J.

    1984-01-01

    The synthesis of purines and pyrimidines using Oparin-Urey-type primitive earth atmospheres has been demonstrated by reacting methane, ethane, and ammonia in electrical discharges. Adenine, guaine, 4-aminoimidazole-5-carboxamide (AICA), and isocytosine have been identified by UV spectrometry and paper chromatography as the products of the reaction. The total yields of the identified heterocyclic compounds are 0.0023 percent. It is concluded that adenine synthesis occurs at a much lower concentration of hydrogen cyanide than has been shown by earlier studies. Pathways for the synthesis of purines from hydrogen cyanide are discussed, and a comparison of the heterocyclic compounds that have been identified in meteorites and in prebiotic reactions is presented.

  1. Substituted N-Phenylpyrazine-2-carboxamides, Their Synthesis and Evaluation as Herbicides and Abiotic Elicitors

    Directory of Open Access Journals (Sweden)

    Katarína Kráľová

    2007-12-01

    Full Text Available The condensation of substituted pyrazine-2-carboxylic acid chlorides with ring-substituted anilines yielded five substituted pyrazine-2-carboxylic acid amides. Thesynthesis, and analytical, lipophilicity and biological data of the newly synthesizedcompounds are presented in this paper. The photosynthesis inhibition, antialgal activityand the effect of a series of pyrazine derivatives as abiotic elicitors on the accumulation offlavonoids in a callus culture of Ononis arvensis (L. were investigated. The most activeinhibitor of the oxygen evolution rate in spinach chloroplasts was 6-chloro-pyrazine-2-carboxylic acid (3-iodo-4-methylphenyl-amide (2, IC50 = 51.0 μmol·L-1. The highestreduction of chlorophyll content in Chlorella vulgaris was found for 5-tert-butyl-N-(4-chloro-3-methylphenyl-pyrazine-2-carboxamide (3, IC50 = 44.0 μmol·L-1. The maximalflavonoid production (about 900% was reached after a twelve-hour elicitation processwith 6-chloropyrazine-2-carboxylic acid (3-iodo-4-methylphenyl-amide (2.

  2. Minerals Masquerading As Enzymes: Abiotic Oxidation Of Soil Organic Matter In An Iron-Rich Humid Tropical Forest Soil

    Science.gov (United States)

    Hall, S. J.; Silver, W. L.

    2010-12-01

    Oxidative reactions play an important role in decomposing soil organic matter fractions that resist hydrolytic degradation, and fundamentally affect the cycling of recalcitrant soil carbon across ecosystems. Microbial extracellular oxidative enzymes (e.g. lignin peroxidases and laccases) have been assumed to provide a dominant role in catalyzing soil organic matter oxidation, while other potential oxidative mechanisms remain poorly explored. Here, we show that abiotic reactions mediated by the oxidation of ferrous iron (Fe(II)) could explain high potential oxidation rates in humid tropical forest soils, which often contain high concentrations of Fe(II) and experience rapid redox fluctuations between anaerobic and aerobic conditions. These abiotic reactions could provide an additional mechanism to explain high rates of decomposition in these ecosystems, despite frequent oxygen deficits. We sampled humid tropical forest soils in Puerto Rico, USA from various topographic positions, ranging from well-drained ridges to riparian valleys that experience broad fluctuations in redox potential. We measured oxidative activity by adding the model humic compound L-DOPA to soil slurries, followed by colorimetric measurements of the supernatant solution over time. Dilute hydrogen peroxide was added to a subset of slurries to measure peroxidative activity. We found that oxidative and peroxidative activity correlated positively with soil Fe(II) concentrations, counter to prevailing theory that low redox potential should suppress oxidative enzymes. Boiling or autoclaving sub-samples of soil slurries to denature any enzymes present typically increased peroxidative activity and did not eliminate oxidative activity, further suggesting the importance of an abiotic mechanism. We found substantial differences in the oxidation products of the L-DOPA substrate generated by our soil slurries in comparison with oxidation products generated by a purified enzyme (mushroom tyrosinase

  3. Interfacial photochemistry of biogenic surfactants: a major source of abiotic volatile organic compounds.

    Science.gov (United States)

    Brüggemann, Martin; Hayeck, Nathalie; Bonnineau, Chloé; Pesce, Stéphane; Alpert, Peter A; Perrier, Sébastien; Zuth, Christoph; Hoffmann, Thorsten; Chen, Jianmin; George, Christian

    2017-08-24

    Films of biogenic compounds exposed to the atmosphere are ubiquitously found on the surfaces of cloud droplets, aerosol particles, buildings, plants, soils and the ocean. These air/water interfaces host countless amphiphilic compounds concentrated there with respect to in bulk water, leading to a unique chemical environment. Here, photochemical processes at the air/water interface of biofilm-containing solutions were studied, demonstrating abiotic VOC production from authentic biogenic surfactants under ambient conditions. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified, giving emission fluxes comparable to previous field and laboratory observations. Interestingly, VOC fluxes increased with the decay of microbial cells in the samples, indicating that cell lysis due to cell death was the main source for surfactants and VOC production. In particular, irradiation of samples containing solely biofilm cells without matrix components exhibited the strongest VOC production upon irradiation. In agreement with previous studies, LC-MS measurements of the liquid phase suggested the presence of fatty acids and known photosensitizers, possibly inducing the observed VOC production via peroxy radical chemistry. Up to now, such VOC emissions were directly accounted to high biological activity in surface waters. However, the results obtained suggest that abiotic photochemistry can lead to similar emissions into the atmosphere, especially in less biologically-active regions. Furthermore, chamber experiments suggest that oxidation (O 3 /OH radicals) of the photochemically-produced VOCs leads to aerosol formation and growth, possibly affecting atmospheric chemistry and climate-related processes, such as cloud formation or the Earth's radiation budget.

  4. Organic synthesis with stable isotopes

    International Nuclear Information System (INIS)

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

    1982-01-01

    Described is a scheme for the synthesis of L-arginine-1- 13 C utilizing methods developed for the synthesis of L-ornithine-1- 13 C from L-ornithine-2- 13 C and then converting ornithine into arginine with the enzyme acylase

  5. Linking the spatial patterns of organisms and abiotic factors to ecosystem function and management: insights from semi-arid environments

    Directory of Open Access Journals (Sweden)

    F. T. Maestre

    2006-12-01

    Full Text Available Numerous theoretical and modeling studies have demonstrated the ecological significance of the spatial patterning of organisms on ecosystem functioning and dynamics. However, there is a paucity of empirical evidence that quantitatively shows how changes in the spatial patterns of the organisms forming biotic communities are directly related to ecosystem structure and functioning. In this article, I review a series of experiments and observational studies conducted in semi-arid environments from Spain (degraded calcareous shrubland, steppes dominated by Stipa tenacissima, and gypsum shrublands to: 1 evaluate whether the spatial patterns of the dominant biotic elements in the community are linked to ecosystem structure and functioning, and 2 test if these patterns, and those of abiotic factors, can be used to improve ecosystem restoration. In the semiarid steppes we found a significant positive relationship between the spatial pattern of the perennial plant community and: i the water status of S. tenacissima and ii perennial species richness and diversity. Experimental plantings conducted in these steppes showed that S. tenacissima facilitated the establishment of shrub seedlings, albeit the magnitude and direction of this effect was dependent on rainfall conditions during the first yr after planting. In the gypsum shrubland, a significant, direct relationship between the spatial pattern of the biological soil crusts and surrogates of ecosystem functioning (soil bulk density and respiration was found. In a degraded shrubland with very low vegetation cover, the survival of an introduced population of the shrub Pistacia lentiscus showed marked spatial patterns, which were related to the spatial patterns of soil properties such as soil compaction and sand content. These results provide empirical evidence on the importance of spatial patterns for maintaining ecosystem structure and functioning in semi-arid ecosystems

  6. Synthesis Road Map Problems in Organic Chemistry

    Science.gov (United States)

    Schaller, Chris P.; Graham, Kate J.; Jones, T. Nicholas

    2014-01-01

    Road map problems ask students to integrate their knowledge of organic reactions with pattern recognition skills to "fill in the blanks" in the synthesis of an organic compound. Students are asked to identify familiar organic reactions in unfamiliar contexts. A practical context, such as a medicinally useful target compound, helps…

  7. Coupling effects of abiotic and biotic factors on molecular composition of dissolved organic matter in a freshwater wetland

    Energy Technology Data Exchange (ETDEWEB)

    He, Wei [Department of Environment and Energy, Sejong University, Seoul 143-747 (Korea, Republic of); Choi, Ilhwan [Water Analysis and Research Center, K-water, 560 Sintanjin-ro, Daedeok-gu, Daejeon 307-711 (Korea, Republic of); Lee, Jung-Joon [Department of Biological Education, Daegu University, Gyungbuk 712-714 (Korea, Republic of); Hur, Jin, E-mail: jinhur@sejong.ac.kr [Department of Environment and Energy, Sejong University, Seoul 143-747 (Korea, Republic of)

    2016-02-15

    In this study, temporal and spatial variations in five defined molecular size fractions of dissolved organic matter (DOM) were examined for a well preserved wetland (Upo Wetland) and its surrounding areas, and the influencing factors were explored with many biotic and abioic parameters. For each DOM sample, the five size fractions were determined by size-exclusion chromatography coupled with organic carbon detector (SEC-OCD). For 2-year long monthly monitoring, bio-polymers (BP), humic substances (HS), building blocks (BB), low molecular-weight (LMW) neutrals, and LMW acids displayed the median values of 264, 1884, 1070, 1090, and 11 μg-C L{sup −1}, respectively, accounting for 6.2%, 41.7%, 24.5%, 26.4%, and 0.4% of dissolved organic carbon (DOC). The dominant presence of HS indicated that terrestrial input played important roles in DOM composition of the freshwater ecosystem, which contrasted with coastal wetlands in other reports. Both seasonal and periodic patterns in the variations were found only for HS and BB among the size fractions. It was also notable that the sources of HS were seasonally shifted from aquagenic origin in winter to pedogenic origin in summer. The correlations among the size fractions revealed that BB and LMW neutrals might be degradation products from HS and humic-like substances (HS + BB), respectively, while LMW acids, from LMW neutrals. Principle component analysis revealed that the humic-like substances and the aromaticity of DOM were associated with temperature, chlorophyll a, phosphorous, and rainfall, whereas the other fractions and the molecular weight of HS were primarily affected by solar irradiation. Significant correlations between DOM composition and some biotic factors further suggested that DOM may even affect the biological communities, which provides an insight into the potential coupling effects of biotic and abiotic factors on DOM molecular composition in freshwater wetlands. - Highlights: • Humic fractions varied

  8. Coupling effects of abiotic and biotic factors on molecular composition of dissolved organic matter in a freshwater wetland

    International Nuclear Information System (INIS)

    He, Wei; Choi, Ilhwan; Lee, Jung-Joon; Hur, Jin

    2016-01-01

    In this study, temporal and spatial variations in five defined molecular size fractions of dissolved organic matter (DOM) were examined for a well preserved wetland (Upo Wetland) and its surrounding areas, and the influencing factors were explored with many biotic and abioic parameters. For each DOM sample, the five size fractions were determined by size-exclusion chromatography coupled with organic carbon detector (SEC-OCD). For 2-year long monthly monitoring, bio-polymers (BP), humic substances (HS), building blocks (BB), low molecular-weight (LMW) neutrals, and LMW acids displayed the median values of 264, 1884, 1070, 1090, and 11 μg-C L"−"1, respectively, accounting for 6.2%, 41.7%, 24.5%, 26.4%, and 0.4% of dissolved organic carbon (DOC). The dominant presence of HS indicated that terrestrial input played important roles in DOM composition of the freshwater ecosystem, which contrasted with coastal wetlands in other reports. Both seasonal and periodic patterns in the variations were found only for HS and BB among the size fractions. It was also notable that the sources of HS were seasonally shifted from aquagenic origin in winter to pedogenic origin in summer. The correlations among the size fractions revealed that BB and LMW neutrals might be degradation products from HS and humic-like substances (HS + BB), respectively, while LMW acids, from LMW neutrals. Principle component analysis revealed that the humic-like substances and the aromaticity of DOM were associated with temperature, chlorophyll a, phosphorous, and rainfall, whereas the other fractions and the molecular weight of HS were primarily affected by solar irradiation. Significant correlations between DOM composition and some biotic factors further suggested that DOM may even affect the biological communities, which provides an insight into the potential coupling effects of biotic and abiotic factors on DOM molecular composition in freshwater wetlands. - Highlights: • Humic fractions varied

  9. Abiotic reaction of iodate with sphagnum peat and other natural organic matter

    International Nuclear Information System (INIS)

    Steinberg, S.M.; Kimble, G.; Schmett, G.T.; Emerson, D.W.; Turner, M.F.; Rudin, M.

    2008-01-01

    Previous studies have shown that iodine (including 129 I) can be strongly retained in organic-rich surface soils and sediment and that a large fraction of soluble iodine may be associated with dissolved humic material. Iodate (IO 3 - ) reacts with natural organic matter (NOM) producing either hypoiodous acid (HIO) or I 2 as an intermediate. This intermediate is subsequently incorporated into the organic matter. Based on reactions of model compounds, we infer that iodine reacts with peat by aromatic substitution of hydrogen on phenolic constituents of the peat. Alternatively, the intermediate, HIO or I 2 , may be reduced to iodide (I - ). The pH (and temperature) dependence of the IO 3 - reaction (reduction) has been explored with sphagnum peat, alkali lignin, and several model compounds. The incorporation of iodine into NOM has been verified by pyrolysis gas chromatography/mass spectrometry (GC/MS). Model compound studies indicate that reduction of IO 3 - to HIO may result from reaction with hydroquinone (or semiquinone) moieties of the peat. (author)

  10. Selenium and tellurium reagents in organic synthesis

    International Nuclear Information System (INIS)

    Comasseto, J.V.

    1984-01-01

    A review of the contribution of the University of Sao Paulo (SP, Brazil) to the organic synthesis of selenium and tellurium reagents is made. Major reactions amoung selenium compounds and insaturated substrates, phosphorus, ester enolates as well as the use of phase transference catalysed reactions to produce arylselenolate are described. For tellurium, interactions of its compounds with organic substrates and reactive intermediates (e.g. benzino diazomethane) are reported. (C.L.B.) [pt

  11. Organic Analysis of Catalytic Fischer-Tropsch Synthesis Products and Ordinary Chondrite Meteorites by Stepwise Pyrolysis-GCMS: Organics in the Early Solar Nebula

    Science.gov (United States)

    Locke, Darren R.; Yazzie, Cyriah A.; Burton, Aaron S.; Niles, Paul B.; Johnson, Natasha M.

    2014-01-01

    Abiotic generation of complex organic compounds, in the early solar nebula that formed our solar system, is hypothesized by some to occur via Fischer-Tropsch (FT) synthesis. In its simplest form, FT synthesis involves the low temperature (300degC) produces FT products that include lesser amounts of n-alkanes and greater alkene, alcohol, and polycyclic aromatic hydrocarbon (PAH) compounds. We have begun to experimentally investigate FT synthesis in the context of abiotic generation of organic compounds in the early solar nebula. It is generally thought that the early solar nebula included abundant hydrogen and carbon monoxide gases and nano-particulate matter such as iron and metal silicates that could have catalyzed the FT reaction. The effect of FT reaction temperature, catalyst type, and experiment duration on the resulting products is being investigated. These solid organic products are analyzed by thermal-stepwise pyrolysis-GCMS and yield the types and distribution of hydrocarbon compounds released as a function of temperature. We show how the FT products vary by reaction temperature, catalyst type, and experimental duration and compare these products to organic compounds found to be indigenous to ordinary chondrite meteorites. We hypothesize that the origin of organics in some chondritic meteorites, that represent an aggregation of materials from the early solar system, may at least in part be from FT synthesis that occurred in the early solar nebula.

  12. Pyrolysis-GCMS Analysis of Solid Organic Products from Catalytic Fischer-Tropsch Synthesis Experiments

    Science.gov (United States)

    Locke, Darren R.; Yazzie, Cyriah A.; Burton, Aaron S.; Niles, Paul B.; Johnson, Natasha M.

    2015-01-01

    Abiotic synthesis of complex organic compounds in the early solar nebula that formed our solar system is hypothesized to occur via a Fischer-Tropsch type (FTT) synthesis involving the reaction of hydrogen and carbon monoxide gases over metal and metal oxide catalysts. In general, at low temperatures (less than 200 C), FTT synthesis is expected to form abundant alkane compounds while at higher temperatures (greater than 200 C) it is expected to product lesser amounts of n-alkanes and greater amounts of alkene, alcohol, and polycyclic aromatic hydrocarbons (PAHs). Experiments utilizing a closed-gas circulation system to study the effects of FTT reaction temperature, catalysts, and number of experimental cycles on the resulting solid insoluble organic products are being performed in the laboratory at NASA Goddard Space Flight Center. These experiments aim to determine whether or not FTT reactions on grain surfaces in the protosolar nebula could be the source of the insoluble organic matter observed in meteorites. The resulting solid organic products are being analyzed at NASA Johnson Space Center by pyrolysis gas chromatography mass spectrometry (PY-GCMS). PY-GCMS yields the types and distribution of organic compounds released from the insoluble organic matter generated from the FTT reactions. Previously, exploratory work utilizing PY-GCMS to characterize the deposited organic materials from these reactions has been reported. Presented here are new organic analyses using magnetite catalyst to produce solid insoluble organic FTT products with varying reaction temperatures and number of experimental cycles.

  13. Carbon Isotope Systematics in Mineral-Catalyzed Hydrothermal Organic Synthesis Processes at High Temperature and Pressures

    Science.gov (United States)

    Fu, Qi; Socki, R. A.; Niles, Paul B.

    2011-01-01

    Observation of methane in the Martian atmosphere has been reported by different detection techniques. Reduction of CO2 and/or CO during serpentization by mineral surface catalyzed Fischer-Tropsch Type (FTT) synthesis may be one possible process responsible for methane generation on Mars. With the evidence a recent study has discovered for serpentinization in deeply buried carbon rich sediments, and more showing extensive water-rock interaction in Martian history, it seems likely that abiotic methane generation via serpentinization reactions may have been common on Mars. Experiments involving mineral-catalyzed hydrothermal organic synthesis processes were conducted at 750 C and 5.5 Kbars. Alkanes, alcohols and carboxylic acids were identified as organic compounds. No "isotopic reversal" of delta C-13 values was observed for alkanes or carboxylic acids, suggesting a different reaction pathway than polymerization. Alcohols were proposed as intermediaries formed on mineral surfaces at experimental conditions. Carbon isotope data were used in this study to unravel the reaction pathways of abiotic formation of organic compounds in hydrothermal systems at high temperatures and pressures. They are instrumental in constraining the origin and evolution history of organic compounds on Mars and other planets.

  14. Asymmetric catalysis in organic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Reilly, S.D.; Click, D.R.; Grumbine, S.K.; Scott, B.L.; Watkins, J.G.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of the project was to prepare new catalyst systems, which would perform chemical reactions in an enantioselective manner so as to produce only one of the possible optical isomers of the product molecule. The authors have investigated the use of lanthanide metals bearing both diolate and Schiff-base ligands as catalysts for the enantioselective reduction of prochiral ketones to secondary alcohols. The ligands were prepared from cheap, readily available starting materials, and their synthesis was performed in a ''modular'' manner such that tailoring of specific groups within the ligand could be carried out without repeating the entire synthetic procedure. In addition, they have developed a new ligand system for Group IV and lanthanide-based olefin polymerization catalysts. The ligand system is easily prepared from readily available starting materials and offers the opportunity to rapidly prepare a wide range of closely related ligands that differ only in their substitution patterns at an aromatic ring. When attached to a metal center, the ligand system has the potential to carry out polymerization reactions in a stereocontrolled manner.

  15. Organic and biochemical synthesis group

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Stable isotopes, because of their unique properties and non-radioactive nature, have great potential for many fields of science and technology. In particular, isotopes of carbon, nitrogen, oxygen, and sulfur (the basic building blocks of all biological molecules) would be widely used in biomedical and environmental research if they were economically available in sufficient quantities and in the required chemical forms. The major objective of our program continues to be stimulation of the widespread utilization of stable isotopes and commercial involvement through development and demonstration of applications which have potential requirements for large quantities of isotopes. Thus, demand will be created which is necessary for large-scale production of stable isotopes and labeled compounds and concomitant low unit costs. The program continues to produce a variety of labeled materials needed for clinical, biomedical, chemical, and environmental applications which serve as effective demonstrations of unique and advantageous utilization of stable isotopes. Future commercial involvement should benefit, and is a consideration in our research and development, from the technology transfer that can readily be made as a result of our organic and biochemical syntheses and also of various techniques involved in applications

  16. [Effect of abiotic and biotic factors on the structural and functional organization of the saline lake ecosystems in Crimea].

    Science.gov (United States)

    Balushkina, E V; Golubkov, S M; Golubkov, M S; Litvinchuk, L F; Shadrin, N V

    2009-01-01

    Decrease of both zooplankton and zoobenthos species richness and a trend toward decrease of their biomass with the salinity increase was recorded in the hypersaline lakes of Crimea. The most of structural and functional characteristics of macrobenthos is positively correlated with abiotic and biotic characteristics of those lakes. Abundance, biomass, productivity of macrobenthos and ration of non-predating macrozoobenthos decrease with salinity increase, while they increase with the depth and growth of amount of chlorophyll a and primary production. Macrozoobenthos portion in the total zooplankton and macrozoobenthos biomass decreases with both salinity and depth increase. Zooplankton community is less controlled by abiotic factors as compared to macrozoobenthos, while the former's species number significantly decrease with salinity increase. Effect of salinity on zooplankton biomass is slightly significant, unlike that of macrozoobenthos. Comparison of total amount of rations of zooplankton and macrozoobenthos with amount of primary production indicates intense trophic interactions in the lakes under study.

  17. Synthesis-Spectroscopy Roadmap Problems: Discovering Organic Chemistry

    Science.gov (United States)

    Kurth, Laurie L.; Kurth, Mark J.

    2014-01-01

    Organic chemistry problems that interrelate and integrate synthesis with spectroscopy are presented. These synthesis-spectroscopy roadmap (SSR) problems uniquely engage second-year undergraduate organic chemistry students in the personal discovery of organic chemistry. SSR problems counter the memorize-or-bust strategy that many students tend to…

  18. Enantioselective biotransformations of nitriles in organic synthesis.

    Science.gov (United States)

    Wang, Mei-Xiang

    2015-03-17

    The hydration and hydrolysis of nitriles are valuable synthetic methods used to prepare carboxamides and carboxylic acids. However, chemical hydration and hydrolysis of nitriles involve harsh reaction conditions, have low selectivity, and generate large amounts of waste. Therefore, researchers have confined the scope of these reactions to simple nitrile substrates. However, biological transformations of nitriles are highly efficient, chemoselective, and environmentally benign, which has led synthetic organic chemists and biotechologists to study these reactions in detail over the last two decades. In nature, biological systems degrade nitriles via two distinct pathways: nitrilases catalyze the direct hydrolysis of nitriles to afford carboxylic acids with release of ammonia, and nitrile hydratases catalyze the conversion of nitriles into carboxamides, which then furnish carboxylic acids via hydrolysis in the presence of amidases. Researchers have subsequently developed biocatalytic methods into useful industrial processes for the manufacture of commodity chemicals, including acrylamide. Since the late 1990s, research by my group and others has led to enormous progress in the understanding and application of enantioselective biotransformations of nitriles in organic synthesis. In this Account, I summarize the important advances in enantioselective biotransformations of nitriles and amides, with a primary focus on research from my laboratory. I describe microbial whole-cell-catalyzed kinetic resolution of various functionalized nitriles, amino- and hydroxynitriles, and nitriles that contain small rings and the desymmetrization of prochiral and meso dinitriles and diamides. I also demonstrate how we can apply the biocatalytic protocol to synthesize natural products and bioactive compounds. These nitrile biotransformations offer an attractive and unique protocol for the enantioselective synthesis of polyfunctionalized organic compounds that are not readily obtainable by

  19. Novel Aryne Chemistry in Organic Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhijian [Iowa State Univ., Ames, IA (United States)

    2006-12-12

    Arynes are among the most intensively studied systems in chemistry. However, many aspects of the chemistry of these reactive intermediates are not well understood yet and their use as reagents in synthetic organic chemistry has been somewhat limited, due to the harsh conditions needed to generate arynes and the often uncontrolled reactivity exhibited by these species. Recently, o-silylaryl triflates, which can generate the corresponding arynes under very mild reaction conditions, have been found very useful in organic synthesis. This thesis describes several novel and useful methodologies by employing arynes, which generate from o-silylaryl triflates, in organic synthesis. An efficient, reliable method for the N-arylation of amines, sulfonamides and carbamates, and the O-arylation of phenols and carboxylic acids is described in Chapter 1. Amines, sulfonamides, phenols, and carboxylic acids are good nucleophiles, which can react with arynes generated from a-silylaryl triflates to afford the corresponding N- and O-arylated products in very high yields. The regioselectivity of unsymmetrical arynes has also been studied. A lot of useful, functional groups can tolerate our reaction conditions. Carbazoles and dibenzofurans are important heteroaromatic compounds, which have a variety of biological activities. A variety of substituted carbazoles and dibenzofwans are readily prepared in good to excellent yields starting with the corresponding o-iodoanilines or o-iodophenols and o-silylaryl triflates by a treatment with CsF, followed by a Pd-catalyzed cyclization, which overall provides a one-pot, two-step process. By using this methodology, the carbazole alkaloid mukonine has been concisely synthesized in a very good yield. Insertion of an aryne into a σ-bond between a nucleophile and an electrophile (Nu-E) should potentially be a very beneficial process from the standpoint of organic synthesis. A variety of substituted ketones and sulfoxides have been synthesized in good

  20. Interactive effects of MnO2, organic matter and pH on abiotic formation of N2O from hydroxylamine in artificial soil mixtures

    Science.gov (United States)

    Liu, Shurong; Berns, Anne E.; Vereecken, Harry; Wu, Di; Brüggemann, Nicolas

    2017-02-01

    Abiotic conversion of the reactive nitrification intermediate hydroxylamine (NH2OH) to nitrous oxide (N2O) is a possible mechanism of N2O formation during nitrification. Previous research has demonstrated that manganese dioxide (MnO2) and organic matter (OM) content of soil as well as soil pH are important control variables of N2O formation in the soil. But until now, their combined effect on abiotic N2O formation from NH2OH has not been quantified. Here, we present results from a full-factorial experiment with artificial soil mixtures at five different levels of pH, MnO2 and OM, respectively, and quantified the interactive effects of the three variables on the NH2OH-to-N2O conversion ratio (RNH2OH-to-N2O). Furthermore, the effect of OM quality on RNH2OH-to-N2O was determined by the addition of four different organic materials with different C/N ratios to the artificial soil mixtures. The experiments revealed a strong interactive effect of soil pH, MnO2 and OM on RNH2OH-to-N2O. In general, increasing MnO2 and decreasing pH increased RNH2OH-to-N2O, while increasing OM content was associated with a decrease in RNH2OH-to-N2O. Organic matter quality also affected RNH2OH-to-N2O. However, this effect was not a function of C/N ratio, but was rather related to differences in the dominating functional groups between the different organic materials.

  1. Organic or organometallic template mediated clay synthesis

    Science.gov (United States)

    Gregar, Kathleen C.; Winans, Randall E.; Botto, Robert E.

    1994-01-01

    A method for incorporating diverse Varieties of intercalants or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and lithium fluoride for two days in the presence of an organic or organometallic intercalant or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue that are based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by U.S. Pat. No. 3,887,454 issued to Hickson, Jun. 13, 1975; however, a variety of intercalants or templates may be introduced. The intercalants or templates should have (i) water-solubility, (ii) positive charge, and (iii) thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays.

  2. Enhanced biotic and abiotic transformation of Cr(vi) by quinone-reducing bacteria/dissolved organic matter/Fe(iii) in anaerobic environment.

    Science.gov (United States)

    Huang, Bin; Gu, Lipeng; He, Huan; Xu, Zhixiang; Pan, Xuejun

    2016-09-14

    This study investigated the simultaneous transformation of Cr(vi) via a closely coupled biotic and abiotic pathway in an anaerobic system of quinone-reducing bacteria/dissolved organic matters (DOM)/Fe(iii). Batch studies were conducted with quinone-reducing bacteria to assess the influences of sodium formate (NaFc), electron shuttling compounds (DOM) and the Fe(iii) on Cr(vi) reduction rates as these chemical species are likely to be present in the environment during in situ bioremediation. Results indicated that the concentration of sodium formate and anthraquinone-2-sodium sulfonate (AQS) had apparently an effect on Cr(vi) reduction. The fastest decrease in rate for incubation supplemented with 5 mM sodium formate and 0.8 mM AQS showed that Fe(iii)/DOM significantly promoted the reduction of Cr(vi). Presumably due to the presence of more easily utilizable sodium formate, DOM and Fe(iii) have indirect Cr(vi) reduction capability. The coexisting cycles of Fe(ii)/Fe(iii) and DOM(ox)/DOM(red) exhibited a higher redox function than the individual cycle, and their abiotic coupling action can significantly enhance Cr(vi) reduction by quinone-reducing bacteria.

  3. Synthesis of polyaryl rigid-core carbosilane dendrimers for supported organic synthesis

    NARCIS (Netherlands)

    Wander, M.; Hausoul, P.J.C.; Sliedregt, L.A.J.M.; van Steen, B.J.; van Koten, G.; Klein Gebbink, R.J.M.

    2009-01-01

    Carbosilane dendrimers can be used as soluble supports for organic synthesis, since their structure allows separation of excess reagents from the supported products, eventually yielding products of high purity and in high yield, as in solid-phase organic synthesis (SPOS). In previous studies often

  4. Mechanochemical synthesis of organic compounds and composites with their participation

    Energy Technology Data Exchange (ETDEWEB)

    Lyakhov, Nikolai Z; Grigorieva, Tatiana F; Barinova, Antonina P; Vorsina, I A [Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2010-05-13

    The results of experimental studies in the mechanochemical synthesis of organic compounds and composites with their participation published over the last 15 years are described systematically. The key reactions of organic compounds are considered: synthesis of the salts of organic acids, acylation, substitution, dehalogenation, esterification, hydrometallation and other reactions. Primary attention is devoted to systems and compounds that cannot be obtained by traditional chemistry methods.

  5. Fundamentals and applications of organic electrochemistry synthesis, materials, devices

    CERN Document Server

    Fuchigami, Toshio; Inagi, Shinsuke

    2014-01-01

    This textbook is an accessible overview of the broad field of organic electrochemistry, covering the fundamentals and applications of contemporary organic electrochemistry.  The book begins with an introduction to the fundamental aspects of electrode electron transfer and methods for the electrochemical measurement of organic molecules. It then goes on to discuss organic electrosynthesis of molecules and macromolecules, including detailed experimental information for the electrochemical synthesis of organic compounds and conducting polymers. Later chapters highlight new methodology for organic electrochemical synthesis, for example electrolysis in ionic liquids, the application to organic electronic devices such as solar cells and LEDs, and examples of commercialized organic electrode processes. Appendices present useful supplementary information including experimental examples of organic electrosynthesis, and tables of physical data (redox potentials of various organic solvents and organic compounds and phy...

  6. Microwave-assisted 'greener' synthesis of organics and nanomaterials

    Science.gov (United States)

    Microwave selective heating techniques in conjunction with greener reaction media are dramatically reducing chemical waste and reaction times in several organic transformations and material synthesis. This presentation summarizes author’s own experience in developing MW-assisted ...

  7. Greener and Sustainable Trends in Synthesis of Organics and Nanomaterials

    Science.gov (United States)

    Trends in greener and sustainable process development during the past 25 years are abridged involving the use of alternate energy inputs (mechanochemistry, ultrasound- or microwave irradiation), photochemistry, and greener reaction media as applied to synthesis of organics and na...

  8. Non-covalent synthesis of organic nanostructures

    NARCIS (Netherlands)

    Prins, L.J.; Timmerman, P.; Reinhoudt, David

    1998-01-01

    This review describes the synthesis, characterization and functionalization of hydrogen bonded, box-like assemblies. These assemblies are formed upon mixing bismelamine calix[4]arenes with a complementary barbiturate in apolar solvents. Various techniques for the characterization have been used,

  9. The effect of soil mineral phases on the abiotic degradation of selected organic compounds. Final report, June 31, 1990--December 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu, S.S.

    1994-12-31

    Funds were received from the United States Department of Energy to study the effects of soil mineral phases on the rates of abiotic degradation of tetraphenylborate (TPB) and diphenylboronic acid (DPBA). In addition to kaolinite and montmorillonite clay minerals, the role of goethite, corundum, manganite, and rutile in the degradation of organoborates was also evaluated. The effects of DPBA, argon, molecular dioxygen (O{sub 2}), temperature, and organic matter on the degradation of organoborates were also measured. The results indicated that TPB and DPBA degraded rapidly on the mineral surfaces. The initial products generated from the degradation of TPB were DPBA and biphenyl; however, further degradation resulted in the formation of phenylboric acid and phenol which persisted even after TPB disappeared. The data also showed that the rate of TPB degradation was faster in kaolinite, a 1:1 clay mineral, than in montmorillonite, a double layer mineral. The initial degradation of TPB by corundum was much higher than goethite, manganite and rutile. However, no further degradation by this mineral was observed where as the degradation of TPB continued by goethite and rutile minerals. Over all, the degradation rate of TPB was the highest for goethite as compared to the other metal oxide minerals. The degradation of TPB and DPBA was a redox reaction where metals (Fe, Al, Ti, Mn) acted as Lewis acids. DPBA and argon retarded the TPB degradation where as molecular oxygen organic matter and temperature increased the rate of TPB disappearance.

  10. Camera-enabled techniques for organic synthesis

    Directory of Open Access Journals (Sweden)

    Steven V. Ley

    2013-05-01

    Full Text Available A great deal of time is spent within synthetic chemistry laboratories on non-value-adding activities such as sample preparation and work-up operations, and labour intensive activities such as extended periods of continued data collection. Using digital cameras connected to computer vision algorithms, camera-enabled apparatus can perform some of these processes in an automated fashion, allowing skilled chemists to spend their time more productively. In this review we describe recent advances in this field of chemical synthesis and discuss how they will lead to advanced synthesis laboratories of the future.

  11. BIOMIMETIC STRATEGIES IN ORGANIC SYNTHESIS. TERPENES

    Directory of Open Access Journals (Sweden)

    V. Kulcitki

    2012-12-01

    Full Text Available The current paper represents an outline of the selected contributions to the biomimetic procedures and approaches for the synthesis of terpenes with complex structure and diverse functionalisation pattern. These include homologation strategies, cyclisations, rearrangements, as well as biomimetic remote functionalisations.

  12. Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

    Czech Academy of Sciences Publication Activity Database

    Manley, David W.; Walton, J. C.

    2015-01-01

    Roč. 11, Sep 9 (2015), s. 1570-1582 ISSN 1860-5397 Institutional support: RVO:61388963 Keywords : carboxylic acids * free radicals * organic synthesis * photocatalysis * titania Subject RIV: CC - Organic Chemistry Impact factor: 2.697, year: 2015 http://www.beilstein-journals.org/bjoc/single/articleFullText.htm?publicId=1860-5397-11-173

  13. Synthesis of Ibuprofen in the Introductory Organic Laboratory

    Science.gov (United States)

    Kjonaas, Richard A.; Williams, Peggy E.; Counce, David A.; Crawley, Lindsey R.

    2011-01-01

    A method for the synthesis of ibuprofen in introductory organic chemistry laboratory courses is reported. This experiment requires two 3-h lab sessions. All of the reactions and techniques are a standard part of any introductory organic chemistry course. In the first lab session, students reduce p-isobutylacetophenone to an alcohol and then…

  14. Synthesis of organic compounds 15 N enriched

    International Nuclear Information System (INIS)

    Oliveira, Claudineia Raquel de; Bendassolli, Jose Albertino; Prestes, Clelber Vieira; Tavares, Glauco Arnold

    2002-01-01

    The aim of this work was to develop urea- 15 N and glycine- 15 N synthesis for agronomic and biological studies. The production of these compounds was evaluated due to the fact of increasing use of urea, comparing to others solid fertilizers and the importance of glycine in the studies of protein metabolism. A non-conventional method was carried out to synthesize urea. The process involved reaction among Co, NH 3 anidrid and S at low temperature (100 deg C) and of pressure (0,81 mPa) compared to the conventional method. Monolise halets reaction was carried out for glycine synthesis with chloroacetic and ammonia 2 deg C. Both compounds are economic viable, they can be produced at a lower price than the trade market one. (author)

  15. Chromium metal organic frameworks and synthesis of metal organic frameworks

    Science.gov (United States)

    Zhou, Hong-Cai; Liu, Tian-Fu; Lian, Xizhen; Zou, Lanfang; Feng, Dawei

    2018-04-24

    The present invention relates to monocrystalline metal organic frameworks comprising chromium ions and carboxylate ligands and the use of the same, for example their use for storing a gas. The invention also relates to methods for preparing metal organic frameworks comprising chromium, titanium or iron ions and carboxylate ligands. The methods of the invention allow such metal organic frameworks to be prepared in monocrystalline or polycrystalline forms.

  16. Organic nanomaterials: synthesis, characterization, and device applications

    CERN Document Server

    Torres, Tomas

    2013-01-01

    Recent developments in nanoscience and nanotechnology have given rise to a new generation of functional organic nanomaterials with controlled morphology and well-defined properties, which enable a broad range of useful applications. This book explores some of the most important of these organic nanomaterials, describing how they are synthesized and characterized. Moreover, the book explains how researchers have incorporated organic nanomaterials into devices for real-world applications.Featuring contributions from an international team of leading nanoscientists, Organic Nanomaterials is divided into five parts:Part One introduces the fundamentals of nanomaterials and self-assembled nanostructuresPart Two examines carbon nanostructures—from fullerenes to carbon nanotubes to graphene—reporting on properties, theoretical studies, and applicationsPart Three investigates key aspects of some inorganic materials, self-assembled monolayers,...

  17. Reactivity of organic compounds in catalytic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Minachev, Kh M; Bragin, O V

    1978-01-01

    A comprehensive review of 1976 Soviet research on catalysis delivered to the 1977 annual session of the USSR Academy of Science Council on Catalysis (Baku 6/16-20/77) covers hydrocarbon reactions, including hydrogenation and hydrogenolysis, dehydrogenation, olefin dimerization and disproportionation, and cyclization and dehydrocyclization (e.g., piperylene cyclization and ethylene cyclotrimerization); catalytic and physicochemical properties of zeolites, including cracking, dehydrogenation, and hydroisomerization catalytic syntheses and conversion of heterocyclic and functional hydrocarbon derivatives, including partial and total oxidation (e.g., of o-xylene to phthalic anhydride); syntheses of thiophenes from alkanes and hydrogen sulfide over certain dehydrogenation catalysts; catalytic syntheses involving carbon oxides ( e.g., the development of a new heterogeneous catalyst for hydroformylation of olefins), and of Co-MgO zeolitic catalysts for synthesis of aliphatic hydrocarbons from carbon dioxide and hydrogen, and fabrication of high-viscosity lubricating oils over bifunctional aluminosilicate catalysts.

  18. Protection of the Abiotic Environment

    International Nuclear Information System (INIS)

    Michel, R.; Hutmacher, K. E.; Landfermann, H. H.

    2004-01-01

    Environmental protection against the dangers arising from ionizing radiation, radioactive materials, and other harmful substances is more than to avoid acute dangers or risks for humans or for non-human living organisms. To allow for a sustainable development the abiotic part of the environment must not be neglected in concepts of environmental protection. The environmental impact of some selected long-lived anthropogenic radionuclides is used to exemplify adverse effects for which a unified approach is needed. To this end, indicators are needed for the assessment of the human impact on the abiotic environment which allows to compare different human actions with respect to sustainability and to choose appropriate measures in the competition for a sustainable development. Such indicators have to account for the dynamics of the different environmental compartments. Using the long-lived radionuclides 14C, 36Cl, 85Kr, and 129I as examples, the importance to consider dynamical models and ecological lifetimes in quantifications of the human impact on the environment is emphasized. Particular problems arise from the natural occurrences and variability of radionuclides and other harmful substances. Suitable indicators for the assessment of human impact on the abiotic compartments air, water, and soil are discussed. (Author) 18 refs

  19. Molecular catalysis and high-volume organic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Khidekel, M L; Vasserberg, V E

    1977-01-01

    The field of catalysis is very wide. The properties of catalysts are briefly reviewed and compared with the properties of enzymes. Various uses of enxymes in industry (sugar from corn, cellulose breakdown, etc.) are pointed out. The types of homogeneous and heterogeneous catalysts for use in organic synthesis are discussed. 48 refs. (SJR)

  20. Synthesis of Bisphenol Z: An Organic Chemistry Experiment

    Science.gov (United States)

    Gregor, Richard W.

    2012-01-01

    A student achievable synthesis of bisphenol Z, 4,4'-(cyclohexane-1,1-diyl)diphenol, from the acid-catalyzed reaction of phenol with cyclohexanone is presented. The experiment exemplifies all the usual pedagogy for the standard topic of electrophilic aromatic substitution present in the undergraduate organic chemistry curriculum, while providing…

  1. Synthesis and Chemistry of Organic Geminal Di- and Triazides.

    Science.gov (United States)

    Häring, Andreas P; Kirsch, Stefan F

    2015-11-06

    This review recapitulates all available literature dealing with the synthesis and reactivity of geminal organic di- and triazides. These compound classes are, to a large extent, unexplored despite their promising chemical properties and their simple preparation. In addition, the chemistry of carbonyl diazide (2) and tetraazidomethane (105) is described in separate sections.

  2. Nanoporous ionic organic networks: from synthesis to materials applications

    OpenAIRE

    Sun, Jian-Ke; Antonietti, Markus; Yuan, Jiayin

    2016-01-01

    The past decade has witnessed rapid progress in the synthesis of nanoporous organic networks or polymer frameworks for various potential applications. Generally speaking, functionalization of porous networks to add extra properties and enhance materials performance could be achieved either during the pore formation (thus a concurrent approach) or by post-synthetic modification (a sequential approach). Nanoporous organic networks which include ion pairs bound in a covalent manner are of specia...

  3. Organic Synthesis in Simulated Interstellar Ice Analogs

    Science.gov (United States)

    Dworkin, Jason P.; Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Deamer, David W.; Elsila, Jamie; Zare, Richard N.

    2001-01-01

    Comets and carbonaceous micrometeorites may have been significant sources of organic compounds on the early Earth. Ices on grains in interstellar dense molecular clouds contain a variety of simple molecules as well as aromatic molecules of various sizes. While in these clouds the icy grains are processed by ultraviolet light and cosmic radiation which produces more complex organic molecules. We have run laboratory simulations to identify the types of molecules which could have been generated photolytically in pre-cometary ices. Experiments were conducted by forming various realistic interstellar mixed-molecular ices with and without polycyclic aromatic hydrocarbons (PAHs) at approx. 10 K under high vacuum irradiated with UV light from a hydrogen plasma lamp. The residue that remained after warming to room temperature was analyzed by HPLC, and by laser desorption mass spectrometry. The residue contains several classes of compounds which may be of prebiotic significance.

  4. Ohmic Heating: An Emerging Concept in Organic Synthesis.

    Science.gov (United States)

    Silva, Vera L M; Santos, Luis M N B F; Silva, Artur M S

    2017-06-12

    The ohmic heating also known as direct Joule heating, is an advanced thermal processing method, mainly used in the food industry to rapidly increase the temperature for either cooking or sterilization purposes. Its use in organic synthesis, in the heating of chemical reactors, is an emerging method that shows great potential, the development of which has started recently. This Concept article focuses on the use of ohmic heating as a new tool for organic synthesis. It presents the fundamentals of ohmic heating and makes a qualitative and quantitative comparison with other common heating methods. A brief description of the ohmic reactor prototype in operation is presented as well as recent examples of its use in organic synthesis at laboratory scale, thus showing the current state of the research. The advantages and limitations of this heating method, as well as its main current applications are also discussed. Finally, the prospects and potential implications of ohmic heating in future research in chemical synthesis are proposed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. 15 CFR 715.1 - Annual declaration requirements for production by synthesis of unscheduled discrete organic...

    Science.gov (United States)

    2010-01-01

    ... production by synthesis of unscheduled discrete organic chemicals (UDOCs). 715.1 Section 715.1 Commerce and... DISCRETE ORGANIC CHEMICALS (UDOCs) § 715.1 Annual declaration requirements for production by synthesis of unscheduled discrete organic chemicals (UDOCs). (a) Declaration of production by synthesis of UDOCs for...

  6. Synthesis of Organics in the Early Solar Nebula

    Science.gov (United States)

    Johnson, Natasha M.; Manning, S.; Nuth, J. A., III

    2007-10-01

    It is unknown what process or processes made the organics that are found or detected in extraterrestrial materials. One process that forms organics are Fischer-Tropsch type (FTT) reactions. Fischer-Tropsch type synthesis produces complex hydrocarbons by hydrogenating carbon monoxide via surface mediated reactions. The products of these reactions have been well-studied using `natural’ catalysts [1] and calculations of the efficiency of FTT synthesis in the Solar Nebula suggest that these types of reactions could make significant contributions to material near three AU [2]. We use FTT synthesis to coat Fe-silicate amorphous grains with organic material to simulate the chemistry in the early Solar Nebula. These coatings are composed of macromolecular organic phases [3]. Previous work also showed that as the grains became coated, Haber-Bosch type reactions took place resulting in nitrogen-bearing organics [4]. Our experiments consist of circulating CO, N2, and H2 gas through Fe- amorphous silicate grains that are maintained at a specific temperature in a closed system. The gases are passed through an FTIR spectrometer and are measured to monitor the reaction progress. Samples are analyzed using FTIR, and GCMS (including pyrolysis) and extraction techniques are used to analyze the organic coatings. These experiments show that these types of reactions are an effective means to produce complex hydrocarbons. We present the analysis of the produced organics (solid and gas phase) and the change in the production rate of several compounds as the grains become coated. Organics generated by this technique could represent the carbonaceous material incorporated in comets and meteorites. References: [1] Hayatsu and Anders 1981. Topics in Current Chemistry 99:1-37. [2] Kress and Tielens 2001. MAPS 36:75-91. [3] Johnson et al. 2004. #1876. 35th LPSC. [4] Hill and Nuth 2003. Astrobiology 3:291-304. This work was supported by a grant from NASA.

  7. Mechanochemical synthesis of small organic molecules

    Directory of Open Access Journals (Sweden)

    Tapas Kumar Achar

    2017-09-01

    Full Text Available With the growing interest in renewable energy and global warming, it is important to minimize the usage of hazardous chemicals in both academic and industrial research, elimination of waste, and possibly recycle them to obtain better results in greener fashion. The studies under the area of mechanochemistry which cover the grinding chemistry to ball milling, sonication, etc. are certainly of interest to the researchers working on the development of green methodologies. In this review, a collection of examples on recent developments in organic bond formation reactions like carbon–carbon (C–C, carbon–nitrogen (C–N, carbon–oxygen (C–O, carbon–halogen (C–X, etc. is documented. Mechanochemical syntheses of heterocyclic rings, multicomponent reactions and organometallic molecules including their catalytic applications are also highlighted.

  8. Organic synthesis provides opportunities to transform drug discovery

    Science.gov (United States)

    Blakemore, David C.; Castro, Luis; Churcher, Ian; Rees, David C.; Thomas, Andrew W.; Wilson, David M.; Wood, Anthony

    2018-03-01

    Despite decades of ground-breaking research in academia, organic synthesis is still a rate-limiting factor in drug-discovery projects. Here we present some current challenges in synthetic organic chemistry from the perspective of the pharmaceutical industry and highlight problematic steps that, if overcome, would find extensive application in the discovery of transformational medicines. Significant synthesis challenges arise from the fact that drug molecules typically contain amines and N-heterocycles, as well as unprotected polar groups. There is also a need for new reactions that enable non-traditional disconnections, more C-H bond activation and late-stage functionalization, as well as stereoselectively substituted aliphatic heterocyclic ring synthesis, C-X or C-C bond formation. We also emphasize that syntheses compatible with biomacromolecules will find increasing use, while new technologies such as machine-assisted approaches and artificial intelligence for synthesis planning have the potential to dramatically accelerate the drug-discovery process. We believe that increasing collaboration between academic and industrial chemists is crucial to address the challenges outlined here.

  9. Abiotic stressors and stress responses

    DEFF Research Database (Denmark)

    Sulmon, Cecile; Van Baaren, Joan; Cabello-Hurtado, Francisco

    2015-01-01

    Abstract Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), we...... review how organisms respond and adapt to chemical- and temperature-induced stresses from molecular to population level. Using field-realistic studies, our integrative analysis aims to compare i) how molecular and physiological mechanisms related to protection, repair and energy allocation can impact...... life history traits of stressed organisms, and ii) to what extent trait responses influence individual and population responses. Common response mechanisms are evident at molecular and cellular scales but become rather difficult to define at higher levels due to evolutionary distance and environmental...

  10. Intramolecular Diels-Alder Reactions in Organic Synthesis

    OpenAIRE

    Sizemore, Nicholas Blandford Luke

    2014-01-01

    Intramolecular Diels-Alder (IMDA) reactions are an important class of reactions in synthetic organic chemistry for the rapid construction of polycyclic frameworks. Three classes of IMDA reactions were investigated synthetically and computationally: 1) all-carbon type 1 IMDA reactions, 2) N-acylnitroso type 2 IMDA reactions, and 3) cyano-azadiene IMDA reactions. The first class was implemented in research toward the total synthesis of maoecrystal Z and isopalhinine A. The second class was stud...

  11. Thallium (III) salts utilization in organic synthesis. Part II

    International Nuclear Information System (INIS)

    Ferraz, H.M.C.

    1989-01-01

    The utilizations of thallium (III) salts in organic synthesis with carbonylic and acitylenic substrates are presented. The reactions of carbonylic substra3ts with kitones and the oxidation reactions of acetylenic substrates are shown. Others reactions including thallium (III) salts and non aromatic unsatured substracts, as cleasage of ethers and epoxide using thallium trinitrate, hydrazones treatments with thallium triacetates, etc, are also mentioned. (C.G.C.) [pt

  12. Organized Mesoporous Alumina: Synthesis, Structure and Potential in Catalysis

    Czech Academy of Sciences Publication Activity Database

    Čejka, Jiří

    2003-01-01

    Roč. 254, - (2003), s. 327-338 ISSN 0926-860X R&D Projects: GA AV ČR IAA4040001; GA ČR GA104/02/0571; GA MŠk ME 404 Institutional research plan: CEZ:AV0Z4040901 Keywords : organized mesoporous alumina * mesoporous molecular sieves * synthesis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.825, year: 2003

  13. Mechanism for the abiotic synthesis of uracil via UV-induced oxidation of pyrimidine in pure H2O ices under astrophysical conditions

    International Nuclear Information System (INIS)

    Bera, Partha P.; Nuevo, Michel; Sandford, Scott A.; Lee, Timothy J.; Milam, Stefanie N.

    2010-01-01

    The UV photoirradiation of pyrimidine in pure H 2 O ices has been explored using second-order Moeller-Plesset perturbation theory and density functional theory methods, and compared with experimental results. Mechanisms studied include those starting with neutral pyrimidine or cationic pyrimidine radicals, and reacting with OH radical. The ab initio calculations reveal that the formation of some key species, including the nucleobase uracil, is energetically favored over others. The presence of one or several water molecules is necessary in order to abstract a proton which leads to the final products. Formation of many of the photoproducts in UV-irradiated H 2 O:pyrimidine=20:1 ice mixtures was established in a previous experimental study. Among all the products, uracil is predicted by quantum chemical calculations to be the most favored, and has been identified in experimental samples by two independent chromatography techniques. The results of the present study strongly support the scenario in which prebiotic molecules, such as the nucleobase uracil, can be formed under abiotic processes in astrophysically relevant environments, namely in condensed phase on the surface of icy, cold grains before being delivered to the telluric planets, like Earth.

  14. Engineering and Applications of fungal laccases for organic synthesis

    Directory of Open Access Journals (Sweden)

    Ballesteros Antonio

    2008-11-01

    Full Text Available Abstract Laccases are multi-copper containing oxidases (EC 1.10.3.2, widely distributed in fungi, higher plants and bacteria. Laccase catalyses the oxidation of phenols, polyphenols and anilines by one-electron abstraction, with the concomitant reduction of oxygen to water in a four-electron transfer process. In the presence of small redox mediators, laccase offers a broader repertory of oxidations including non-phenolic substrates. Hence, fungal laccases are considered as ideal green catalysts of great biotechnological impact due to their few requirements (they only require air, and they produce water as the only by-product and their broad substrate specificity, including direct bioelectrocatalysis. Thus, laccases and/or laccase-mediator systems find potential applications in bioremediation, paper pulp bleaching, finishing of textiles, bio-fuel cells and more. Significantly, laccases can be used in organic synthesis, as they can perform exquisite transformations ranging from the oxidation of functional groups to the heteromolecular coupling for production of new antibiotics derivatives, or the catalysis of key steps in the synthesis of complex natural products. In this review, the application of fungal laccases and their engineering by rational design and directed evolution for organic synthesis purposes are discussed.

  15. α-Imino Esters in Organic Synthesis: Recent Advances.

    Science.gov (United States)

    Eftekhari-Sis, Bagher; Zirak, Maryam

    2017-06-28

    α-Imino esters are useful precursors for the synthesis of a variety of types of natural and unnatural α-amino acid derivatives, with a wide range of biological activities. Due to the adjacent ester group, α-imino esters are more reactive relative to other types of imines and undergo different kinds of reactions, including organometallics addition, metal catalyzed vinylation and alkynylation, aza-Henry, aza-Morita-Baylis-Hillman, imino-ene, Mannich-type, and cycloaddition reactions, as well as hydrogenation and reduction. This review discusses the mechanism, scope, and applications of the reactions of α-imino esters and related compounds in organic synthesis, covering the literature from the last 12 years.

  16. Synthesis and characterization of organically linked ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chory, Christine; Riedel, Ingo; Parisi, Juergen [Energy and Semiconductor Research Laboratory (EHF), University of Oldenburg, Carl-von Ossietzky-Strasse 9-11, 26129 Oldenburg (Germany); Kruska, Carsten; Heimbrodt, Wolfram [Department of Physics and Material Sciences Center, Philipps-University Marburg, Renthof 5, 35032 Marburg (Germany); Feser, Clemens [NEXT ENERGY - EWE Research Centre for Energy Technology e.V., Carl-von Ossietzky-Strasse 15, 26129 Oldenburg (Germany); Beenken, Wichard J.D. [Department of Theoretical Physics I, Ilmenau University of Technology, Weimarer Strasse 25, 98693 Ilmenau (Germany); Hoppe, Harald [Department of Experimental Physics I, Ilmenau University of Technology, Weimarer Strasse 32, 98693 Ilmenau (Germany)

    2012-11-15

    We report on the solution-based synthesis and characterization of three-dimensional networks of ZnO nanoparticles where the formation of structures is achieved by covalently linking the nanocrystals with bifunctional organic ligands. The colloidal synthesis will be presented with application of two ligands that vary in size and binding sites. Furthermore we report on structural characterization of dried powders and thin films by means of X-ray diffraction and electron microscopy in order to examine the regularity of the structures. We also present first investigations of the optical properties and electrical conductance behavior in lateral direction of the differently linked hybrid ZnO networks. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Synthesis and characterization of organically linked ZnO nanoparticles

    International Nuclear Information System (INIS)

    Chory, Christine; Riedel, Ingo; Parisi, Juergen; Kruska, Carsten; Heimbrodt, Wolfram; Feser, Clemens; Beenken, Wichard J.D.; Hoppe, Harald

    2012-01-01

    We report on the solution-based synthesis and characterization of three-dimensional networks of ZnO nanoparticles where the formation of structures is achieved by covalently linking the nanocrystals with bifunctional organic ligands. The colloidal synthesis will be presented with application of two ligands that vary in size and binding sites. Furthermore we report on structural characterization of dried powders and thin films by means of X-ray diffraction and electron microscopy in order to examine the regularity of the structures. We also present first investigations of the optical properties and electrical conductance behavior in lateral direction of the differently linked hybrid ZnO networks. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Production of hydroxyl radicals from abiotic oxidation of pyrite by oxygen under circumneutral conditions in the presence of low-molecular-weight organic acids

    Science.gov (United States)

    Zhang, Peng; Yuan, Songhu

    2017-12-01

    Besides acidic environments, pyrite oxidation also occurs in circumneutral environments, such as well-buffered marine and estuarine sediments and salt marshes where low-molecular-weight organic acids (LMWOAs) (e.g., citrate and oxalate) prevail. However, the production of hydroxyl radicals (radOH) from pyrite oxidation by oxygen (O2) in these circumneutral environments is poorly understood. In this study, radOH production was measured during the abiotic oxidation of pyrite by O2 under circumneutral conditions. A pyrite suspension (50 g/L pyrite) that was buffered at pH 6-8 was exposed to air for oxygenation in the dark. Benzoate (20 mM) was added into the suspension to trap radOH. At pH 7, the cumulative radOH reached 7.5 μM within 420 min in the absence of LMWOAs, whereas it increased to 14.8, 12 and 11.2 μM in the presence of 1 mM ethylenediaminotetraacetate, citrate and oxalate, respectively. When the citrate concentration, which serves as a LMWOAs model, was increased from 0.5 to 5 mM, the cumulative radOH increased from 10.3 to 27.3 μM within 420 min at pH 7. With the decrease in pH from 8 to 6, the cumulative radOH increased from 2.1 to 23.3 μM in the absence of LMWOAs, but it increased from 8.8 to 134.9 μM in the presence of 3 mM citrate. The presence of LMWOAs enhanced the radOH production from pyrite oxidation under circumneutral conditions. In the absence of LMOWAs, radOH is produced mostly from the oxidation of adsorbed Fe(II) by O2. In the presence of citrate, radOH production is attributed mainly to the oxidation of Fe(II)-citrate- by O2 and secondarily to the oxidation of H2O on surface-sulfur defects. The acceleration of pyrite oxidation by Fe(III)-citrate increases radOH production. Fe(II)-citrate- is generated mainly from the complexation of adsorbed Fe(II) by citrate and the reduction of Fe(III)-citrate, and the generation is suppressed by the oxidation of adsorbed Fe(II). Fe(III)-citrate is generated predominantly from Fe

  19. The Stable Isotope Fractionation of Abiotic Reactions: A Benchmark in the Detection of Life

    Science.gov (United States)

    Summers, David P.

    2003-01-01

    mil to as low as -60 % (potentially comparable to that which accompanies the biosynthesis of organic matter). We need to understand what kind of fractionations are observed with reactions under the non-reducing or mildly reducing conditions now thought to be present on the early Earth. While nitrogen is receiving increased attention as a tool for these kinds of analyses, almost nothing is known about the isotope fractionation that one would expect for abiotic sources of fixed/reduced nitrogen. This project will measure the fixation from a series of abiotic reactions that may have been present on the early Earth (and other terrestrial planets) and produced organic material that could have ended up in the rock record. The work will look at a number of reactions, under a non- reducing, or mildly reducing, atmosphere, covering sources of prebiotic organic C & N from shock heating, to photochemistry, to hydrothermal reactions. Some reactions that we plan to study are; Shock heating of a non-reducing atmosphere to produce CO and NO (in collaboration with Chris McKay), formation of formaldehyde (and related compounds) from COY the formation of ammonia from nitrogen oxides (ultimately from NO) by ferrous iron reduction, and the hydrothermal synthesis of compounds including the hydrocarboxylation/hydrocarbonylation reaction (in collaboration with George Cody), reactions of oxalate to form hydrocarbons and other oxygenated compounds and the formation of lipids from oxalic/formic acid (in collaboration with Tom McCollom), and reactions of carbon monoxide & carbon dioxide with N2, ammonia or nitritehitrate to form hydrogen cyanide, nitriles, ammonia/amines and nitrous

  20. Synthesis of the DDT metabolite 2,4-dichloro-1-[2-chloro-1-(4-chlorophenyl)ethenyl]benzene (o-Cl-DDMU) and its detection in abiotic and biotic samples.

    Science.gov (United States)

    Gallistl, Christoph; Proctor, Katie; Bader, Korinna; Vetter, Walter

    2017-07-01

    Technical dichlorodiphenyltrichloroethane (DDT) has been used worldwide as a pesticide since the beginning of the 1940s. Due to its persistence, DDT residues are still ubiquitously distributed in the environment. Photochemical UV degradation has been shown to be a potent degradation path for DDT and most of the resulting photoproducts have been identified up to now. Nevertheless, in 2012, a new DDT metabolite, most likely formed photochemically from DDE, was detected in ray liver samples from Brazil, an area which is highly contaminated with DDT. This study includes photochemical generation, chemical synthesis and isolation of this compound which was verified to consist of both cis- and trans-2,4-dichloro-1-[2-chloro-1-(4-chlorophenyl)ethenyl]benzene. Both stereoisomers were resolved by gas chromatography on a polar capillary column and detected in more than 60 biotic (e.g. marine mammals, birds, human milk) and abiotic samples (fat deposits in kitchen hoods) from different areas all over the world. The stereoisomer distribution and concentrations (0.3-3.9% relative to corresponding 1,1-dichloro-2,2-bis(p-chlorophenyl) ethane (p,p'-DDE) levels) were determined by means of the synthesized analytical standard, indicating the widespread occurrence of this compound as an additional minor metabolite of DDT.

  1. Prebiotic Synthesis of Methionine and Other Sulfur-Containing Organic Compounds on the Primitive Earth: A Contemporary Reassessment Based on an Unpublished 1958 Stanley Miller Experiment

    Science.gov (United States)

    Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; Lazcano, Antonio

    2010-01-01

    Original extracts from an unpublished 1958 experiment conducted by the late Stanley L. Miller were recently found and analyzed using modern state-of-the-art analytical methods. The extracts were produced by the action of an electric discharge on a mixture of methane (CH4), hydrogen sulfide (H2S), ammonia (NH3), and carbon dioxide (CO2). Racemic methionine was farmed in significant yields, together with other sulfur-bearing organic compounds. The formation of methionine and other compounds from a model prebiotic atmosphere that contained H2S suggests that this type of synthesis is robust under reducing conditions, which may have existed either in the global primitive atmosphere or in localized volcanic environments on the early Earth. The presence of a wide array of sulfur-containing organic compounds produced by the decomposition of methionine and cysteine indicates that in addition to abiotic synthetic processes, degradation of organic compounds on the primordial Earth could have been important in diversifying the inventory of molecules of biochemical significance not readily formed from other abiotic reactions, or derived from extraterrestrial delivery.

  2. Electrical energy sources for organic synthesis on the early earth

    Science.gov (United States)

    Chyba, Christopher; Sagan, Carl

    1991-01-01

    It is pointed out that much of the contemporary origin-of-life research uses the original estimates of Miller and Urey (1959) for terrestrial energy dissipation by lightning and coronal discharges being equal to 2 x 10 to the 19th J/yr and 6 x 10 to the 19th J/yr, respectively. However, data from experiments that provide analogues to naturally-occurring lightning and coronal discharges indicate that lightning energy yields for organic synthesis (nmole/J) are about one order of magnitude higher than the coronal discharge yields. This suggests that, on early earth, organic production by lightning may have dominated that due to coronal emission. New values are recommended for lightning and coronal discharge dissipation rates on the early earth, 1 x 10 to the 18th J/yr and 5 x 10 to the 17th J/yr, respectively.

  3. Metal–organic framework membranes: from synthesis to separation application

    KAUST Repository

    Qiu, Shilun

    2014-06-26

    Metal-organic framework (MOF) materials, which are constructed from metal ions or metal ion clusters and bridging organic linkers, exhibit regular crystalline lattices with relatively well-defined pore structures and interesting properties. As a new class of porous solid materials, MOFs are attractive for a variety of industrial applications including separation membranes-a rapidly developing research area. Many reports have discussed the synthesis and applications of MOFs and MOF thin films, but relatively few have addressed MOF membranes. This critical review provides an overview of the diverse MOF membranes that have been prepared, beginning with a brief introduction to the current techniques for the fabrication of MOF membranes. Gas and liquid separation applications with different MOF membranes are also included (175 references). This journal is © the Partner Organisations 2014.

  4. Greener and Sustainable Trends in Synthesis of Organics and ...

    Science.gov (United States)

    Trends in greener and sustainable process development during the past 25 years are abridged involving the use of alternate energy inputs (mechanochemistry, ultrasound- or microwave irradiation), photochemistry, and greener reaction media as applied to synthesis of organics and nanomaterials. In the organic synthesis arena, examples comprise assembly of heterocyclic compounds, coupling and a variety of other name reactions catalyzed by basic water or recyclable magnetic nanocatalysts. Generation of nanoparticles benefits from the biomimetic approaches where vitamins, sugars, and plant polyphenols, including agricultural waste residues, can serve as reducing and capping agents. Metal nanocatalysts (Pd, Au, Ag, Ni, Ru, Ce, Cu, etc.) immobilized on biodegradable supports such as cellulose and chitosan, or on recyclable magnetic ferrites via ligands, namely dopamine or glutathione, are receiving special attention. These strategic approaches attempt to address most of the Green Chemistry Principles while producing functional chemicals with utmost level of waste minimization. Feature article for celebration of 25 years of Green Chemistry on invitation from American Chemical Society (ACS) journal, ACS Sustainable Chemistry & Engineering.

  5. Methane clumped isotopes in the Songliao Basin (China): New insights into abiotic vs. biotic hydrocarbon formation

    Science.gov (United States)

    Shuai, Yanhua; Etiope, Giuseppe; Zhang, Shuichang; Douglas, Peter M. J.; Huang, Ling; Eiler, John M.

    2018-01-01

    Abiotic hydrocarbon gas, typically generated in serpentinized ultramafic rocks and crystalline shields, has important implications for the deep biosphere, petroleum systems, the carbon cycle and astrobiology. Distinguishing abiotic gas (produced by chemical reactions like Sabatier synthesis) from biotic gas (produced from degradation of organic matter or microbial activity) is sometimes challenging because their isotopic and molecular composition may overlap. Abiotic gas has been recognized in numerous locations on the Earth, although there are no confirmed instances where it is the dominant source of commercially valuable quantities in reservoir rocks. The deep hydrocarbon reservoirs of the Xujiaweizi Depression in the Songliao Basin (China) have been considered to host significant amounts of abiotic methane. Here we report methane clumped-isotope values (Δ18) and the isotopic composition of C1-C3 alkanes, CO2 and helium of five gas samples collected from those Xujiaweizi deep reservoirs. Some geochemical features of these samples resemble previously suggested identifiers of abiotic gas (13C-enriched CH4; decrease in 13C/12C ratio with increasing carbon number for the C1-C4 alkanes; abundant, apparently non-biogenic CO2; and mantle-derived helium). However, combining these constraints with new measurements of the clumped-isotope composition of methane and careful consideration of the geological context, suggests that the Xujiaweizi depression gas is dominantly, if not exclusively, thermogenic and derived from over-mature source rocks, i.e., from catagenesis of buried organic matter at high temperatures. Methane formation temperatures suggested by clumped-isotopes (167-213 °C) are lower than magmatic gas generation processes and consistent with the maturity of local source rocks. Also, there are no geological conditions (e.g., serpentinized ultramafic rocks) that may lead to high production of H2 and thus abiotic production of CH4 via CO2 reduction. We propose

  6. Natural Product Total Synthesis in the Organic Laboratory: Total Synthesis of Caffeic Acid Phenethyl Ester (CAPE), a Potent 5-Lipoxygenase Inhibitor from Honeybee Hives

    Science.gov (United States)

    Touaibia, Mohamed; Guay, Michel

    2011-01-01

    Natural products play a critical role in modern organic synthesis and learning synthetic techniques is an important component of the organic laboratory experience. In addition to traditional one-step organic synthesis laboratories, a multistep natural product synthesis is an interesting experiment to challenge students. The proposed three-step…

  7. Root Systems of Individual Plants, and the Biotic and Abiotic Factors Controlling Their Depth and Distribution: a Synthesis Using a Global Database.

    Science.gov (United States)

    Tumber-Davila, S. J.; Schenk, H. J.; Jackson, R. B.

    2017-12-01

    This synthesis examines plant rooting distributions globally, by doubling the number of entries in the Root Systems of Individual Plants database (RSIP) created by Schenk and Jackson. Root systems influence many processes, including water and nutrient uptake and soil carbon storage. Root systems also mediate vegetation responses to changing climatic and environmental conditions. Therefore, a collective understanding of the importance of rooting systems to carbon sequestration, soil characteristics, hydrology, and climate, is needed. Current global models are limited by a poor understanding of the mechanisms affecting rooting, carbon stocks, and belowground biomass. This improved database contains an extensive bank of records describing the rooting system of individual plants, as well as detailed information on the climate and environment from which the observations are made. The expanded RSIP database will: 1) increase our understanding of rooting depths, lateral root spreads and above and belowground allometry; 2) improve the representation of plant rooting systems in Earth System Models; 3) enable studies of how climate change will alter and interact with plant species and functional groups in the future. We further focus on how plant rooting behavior responds to variations in climate and the environment, and create a model that can predict rooting behavior given a set of environmental conditions. Preliminary results suggest that high potential evapotranspiration and seasonality of precipitation are indicative of deeper rooting after accounting for plant growth form. When mapping predicted deep rooting by climate, we predict deepest rooting to occur in equatorial South America, Africa, and central India.

  8. Genome-wide analysis of the grapevine stilbene synthase multigenic family: genomic organization and expression profiles upon biotic and abiotic stresses

    Directory of Open Access Journals (Sweden)

    Vannozzi Alessandro

    2012-08-01

    Full Text Available Abstract Background Plant stilbenes are a small group of phenylpropanoids, which have been detected in at least 72 unrelated plant species and accumulate in response to biotic and abiotic stresses such as infection, wounding, UV-C exposure and treatment with chemicals. Stilbenes are formed via the phenylalanine/polymalonate-route, the last step of which is catalyzed by the enzyme stilbene synthase (STS, a type III polyketide synthase (PKS. Stilbene synthases are closely related to chalcone synthases (CHS, the key enzymes of the flavonoid pathway, as illustrated by the fact that both enzymes share the same substrates. To date, STSs have been cloned from peanut, pine, sorghum and grapevine, the only stilbene-producing fruiting-plant for which the entire genome has been sequenced. Apart from sorghum, STS genes appear to exist as a family of closely related genes in these other plant species. Results In this study a complete characterization of the STS multigenic family in grapevine has been performed, commencing with the identification, annotation and phylogenetic analysis of all members and integration of this information with a comprehensive set of gene expression analyses including healthy tissues at differential developmental stages and in leaves exposed to both biotic (downy mildew infection and abiotic (wounding and UV-C exposure stresses. At least thirty-three full length sequences encoding VvSTS genes were identified, which, based on predicted amino acid sequences, cluster in 3 principal groups designated A, B and C. The majority of VvSTS genes cluster in groups B and C and are located on chr16 whereas the few gene family members in group A are found on chr10. Microarray and mRNA-seq expression analyses revealed different patterns of transcript accumulation between the different groups of VvSTS family members and between VvSTSs and VvCHSs. Indeed, under certain conditions the transcriptional response of VvSTS and VvCHS genes appears to be

  9. Nanoporous ionic organic networks: from synthesis to materials applications.

    Science.gov (United States)

    Sun, Jian-Ke; Antonietti, Markus; Yuan, Jiayin

    2016-11-21

    The past decade has witnessed rapid progress in the synthesis of nanoporous organic networks or polymer frameworks for various potential applications. Generally speaking, functionalization of porous networks to add extra properties and enhance materials performance could be achieved either during the pore formation (thus a concurrent approach) or by post-synthetic modification (a sequential approach). Nanoporous organic networks which include ion pairs bound in a covalent manner are of special importance and possess extreme application profiles. Within these nanoporous ionic organic networks (NIONs), here with a pore size in the range from sub-1 nm to 100 nm, we observe a synergistic coupling of the electrostatic interaction of charges, the nanoconfinement within pores and the addressable functional units in soft matter resulting in a wide variety of functions and applications, above all catalysis, energy storage and conversion, as well as environment-related operations. This review aims to highlight the recent progress in this area, and seeks to raise original perspectives that will stimulate future advancements at both the fundamental and applied level.

  10. The effect of soil mineral phases on the abiotic degradation of selected organic compounds. Progress report, June 31, 1990--May 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu, S.S.

    1993-05-31

    Tetraphenylborate (TPB) is used to precipitate radioactive 137Cs from high-level nuclear waste water at the Defense Waste Processing Facility (DWPF) operated by the US DOE at the Savannah River Plant (SRP). The process is part of the procedure for the glassification of high-level nuclear waste in preparation for its long-term geological disposal. The decontaminated waste water contains millimolar quantities of TPB that will be processed into salt concretions. The transporation and use of large amounts of TPB can potentially result in the release of TPB into soil or aquatic environments. Previous study has shown that TPB degrades in soils to initially form diphenylborinic acid (DPBA) and biphenyl. DPBA appears to degrade further into other unidentified compounds which subsequently degrade into inorganic boron. The factors which promote the abiotic degradation of TPB need to be investigated since this chemical is used in the processing of radioactive wastes. TPB and its intermediate product, DPBA, have been reported to be toxic to microorganisms and plants, dependent on soil or water environments for their survival and growth.

  11. Sustainable Alternatives for the Synthesis of Organics and Nanomaterials

    Science.gov (United States)

    The presentation summarizes recent activity in eco-friendly chemical synthesis, which involves benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions. The synthesis of heterocyclic compounds, coupling reaction...

  12. Sustainable Strategies for the Synthesis of Organics and Nanomaterials

    Science.gov (United States)

    The presentation summarizes recent activity in eco-friendly chemical synthesis, which involves benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions. The synthesis of heterocyclic compounds, coupling reaction...

  13. Synthesis of 10-Ethyl Flavin: A Multistep Synthesis Organic Chemistry Laboratory Experiment for Upper-Division Undergraduate Students

    Science.gov (United States)

    Sichula, Vincent A.

    2015-01-01

    A multistep synthesis of 10-ethyl flavin was developed as an organic chemistry laboratory experiment for upper-division undergraduate students. Students synthesize 10-ethyl flavin as a bright yellow solid via a five-step sequence. The experiment introduces students to various hands-on experimental organic synthetic techniques, such as column…

  14. Abiotic methane formation during experimental serpentinization of olivine.

    Science.gov (United States)

    McCollom, Thomas M

    2016-12-06

    Fluids circulating through actively serpentinizing systems are often highly enriched in methane (CH 4 ). In many cases, the CH 4 in these fluids is thought to derive from abiotic reduction of inorganic carbon, but the conditions under which this process can occur in natural systems remain unclear. In recent years, several studies have reported abiotic formation of CH 4 during experimental serpentinization of olivine at temperatures at or below 200 °C. However, these results seem to contradict studies conducted at higher temperatures (300 °C to 400 °C), where substantial kinetic barriers to CH 4 synthesis have been observed. Here, the potential for abiotic formation of CH 4 from dissolved inorganic carbon during olivine serpentinization is reevaluated in a series of laboratory experiments conducted at 200 °C to 320 °C. A 13 C-labeled inorganic carbon source was used to unambiguously determine the origin of CH 4 generated in the experiments. Consistent with previous high-temperature studies, the results indicate that abiotic formation of CH 4 from reduction of dissolved inorganic carbon during the experiments is extremely limited, with nearly all of the observed CH 4 derived from background sources. The results indicate that the potential for abiotic synthesis of CH 4 in low-temperature serpentinizing environments may be much more limited than some recent studies have suggested. However, more extensive production of CH 4 was observed in one experiment performed under conditions that allowed an H 2 -rich vapor phase to form, suggesting that shallow serpentinization environments where a separate gas phase is present may be more favorable for abiotic synthesis of CH 4 .

  15. Development of new methods in modern selective organic synthesis: preparation of functionalized molecules with atomic precision

    International Nuclear Information System (INIS)

    Ananikov, V P; Khemchyan, L L; Ivanova, Yu V; Dilman, A D; Levin, V V; Bukhtiyarov, V I; Sorokin, A M; Prosvirin, I P; Romanenko, A V; Simonov, P A; Vatsadze, S Z; Medved'ko, A V; Nuriev, V N; Nenajdenko, V G; Shmatova, O I; Muzalevskiy, V M; Koptyug, I V; Kovtunov, K V; Zhivonitko, V V; Likholobov, V A

    2014-01-01

    The challenges of the modern society and the growing demand of high-technology sectors of industrial production bring about a new phase in the development of organic synthesis. A cutting edge of modern synthetic methods is introduction of functional groups and more complex structural units into organic molecules with unprecedented control over the course of chemical transformation. Analysis of the state-of-the-art achievements in selective organic synthesis indicates the appearance of a new trend — the synthesis of organic molecules, biologically active compounds, pharmaceutical substances and smart materials with absolute selectivity. Most advanced approaches to organic synthesis anticipated in the near future can be defined as 'atomic precision' in chemical reactions. The present review considers selective methods of organic synthesis suitable for transformation of complex functionalized molecules under mild conditions. Selected key trends in the modern organic synthesis are considered including the preparation of organofluorine compounds, catalytic cross-coupling and oxidative cross-coupling reactions, atom-economic addition reactions, methathesis processes, oxidation and reduction reactions, synthesis of heterocyclic compounds, design of new homogeneous and heterogeneous catalytic systems, application of photocatalysis, scaling up synthetic procedures to industrial level and development of new approaches to investigation of mechanisms of catalytic reactions. The bibliography includes 840 references

  16. Designing cooperatively folded abiotic uni- and multimolecular helix bundles

    Science.gov (United States)

    de, Soumen; Chi, Bo; Granier, Thierry; Qi, Ting; Maurizot, Victor; Huc, Ivan

    2018-01-01

    Abiotic foldamers, that is foldamers that have backbones chemically remote from peptidic and nucleotidic skeletons, may give access to shapes and functions different to those of peptides and nucleotides. However, design methodologies towards abiotic tertiary and quaternary structures are yet to be developed. Here we report rationally designed interactional patterns to guide the folding and assembly of abiotic helix bundles. Computational design facilitated the introduction of hydrogen-bonding functionalities at defined locations on the aromatic amide backbones that promote cooperative folding into helix-turn-helix motifs in organic solvents. The hydrogen-bond-directed aggregation of helices not linked by a turn unit produced several thermodynamically and kinetically stable homochiral dimeric and trimeric bundles with structures that are distinct from the designed helix-turn-helix. Relative helix orientation within the bundles may be changed from parallel to tilted on subtle solvent variations. Altogether, these results prefigure the richness and uniqueness of abiotic tertiary structure behaviour.

  17. Recent Applications of Polymer Supported Organometallic Catalysts in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Nina Kann

    2010-09-01

    Full Text Available Recent developments concerning the application of polymer supported organometallic reagents in solid phase synthesis are reviewed, with a special focus on methodology for carbon-carbon formation. Examples of reactions that are covered include the classical Suzuki, Sonogashira and Heck coupings, but also aryl amination, epoxide opening, rearrangements, metathesis and cyclopropanation. Applications in the field of asymmetric synthesis are also discussed.

  18. Sustainable Synthesis of Organics and Nanomaterials Using Microwave Irradiation

    Science.gov (United States)

    MW-assisted synthesis of heterocyclic compounds and nanomaterials under benign conditions is summarized. Shape-controlled aqueous synthesis of noble nanostructures via MW spontaneous reduction of metal salts using -D-glucose, sucrose, and maltose will be presented. A general met...

  19. Strategies for the Green Synthesis of Organics and Nanomaterials

    Science.gov (United States)

    The presentation summarizes our recent activity in chemical synthesis involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a varie...

  20. The CP molecule labyrinth: a paradigm of how endeavors in total synthesis lead to discoveries and inventions in organic synthesis.

    Science.gov (United States)

    Nicolaou, K C; Baran, Phil S

    2002-08-02

    Imagine an artist carving a sculpture from a marble slab and finding gold nuggets in the process. This thought is not a far-fetched description of the work of a synthetic chemist pursuing the total synthesis of a natural product. At the end of the day, he or she will be judged by the artistry of the final work and the weight of the gold discovered in the process. However, as colorful as this description of total synthesis may be, it does not entirely capture the essence of the endeavor, for there is much more to be told, especially with regard to the contrast of frustrating failures and exhilarating moments of discovery. To fully appreciate the often Herculean nature of the task and the rewards that accompany it, one must sense the details of the enterprise behind the scenes. A more vivid description of total synthesis as a struggle against a tough opponent is perhaps appropriate to dramatize these elements of the experience. In this article we describe one such endeavor of total synthesis which, in addition to reaching the target molecule, resulted in a wealth of new synthetic strategies and technologies for chemical synthesis. The total synthesis of the CP molecules is compared to Theseus' most celebrated athlos (Greek for exploit, accomplishment): the conquest of the dreaded Minotaur, which he accomplished through brilliance, skill, and bravery having traversed the famous labyrinth with the help of Ariadne. This story from Greek mythology comes alive in modern synthetic expeditions toward natural products as exemplified by the total synthesis of the CP molecules which serve as a paradigm for modern total synthesis endeavors, where the objectives are discovery and invention in the broader sense of organic synthesis.

  1. Synthesis of Thin Film Composite Metal-Organic Frameworks Membranes on Polymer Supports

    KAUST Repository

    Barankova, Eva

    2017-01-01

    Since the discovery of size-selective metal-organic frameworks (MOF) researchers have tried to manufacture them into gas separation membranes. ZIF-8 became the most studied MOF for membrane applications mainly because of its simple synthesis, good

  2. Carbon Isotope Characterization of Organic Intermediaries in Hydrothermal Hydrocarbon Synthesis by Pyrolysis-GC-MS-C-IRMS

    Science.gov (United States)

    Socki, Richard A.; Fu, Qi; Niles, Paul B.

    2010-01-01

    We report results of experiments designed to characterize the carbon isotope composition of intermediate organic compounds produced as a result of mineral surface catalyzed reactions. The impetus for this work stems from recently reported detection of methane in the Martian atmosphere coupled with evidence showing extensive water-rock interaction during Martian history. Abiotic formation by Fischer-Tropsch-type (FTT) synthesis during serpentinization reactions may be one possible process responsible for methane generation on Mars, and measurement of carbon and hydrogen isotopes of intermediary organic compounds can help constrain the origin of this methane. Of particular interest within the context of this work is the isotopic composition of organic intermediaries produced on the surfaces of mineral catalysts (i.e. magnetite) during hydrothermal experiments, and the ability to make meaningful and reproducible isotope measurements. Our isotope measurements utilize a unique analytical technique combining Pyrolysis-Gas Chromatograph-Mass Spectrometry-Combustion-Isotope Ratio Mass Specrometry (Py-GC-MS-C-IRMS). Others have conducted similar pyrolysis-IRMS experiments on low molecular weight organic acids (Dias, et al, Organic Geochemistry, 33 [2002]). Our technique differs in that it carries a split of the pyrolyzed GC-separated product to a Thermo DSQ-II quadrupole mass spectrometer as a means of making qualitative and semi-quantitative compositional measurements of the organic compounds. A sample of carboxylic acid (mixture of C1 through C6) was pyrolyzed at 100 XC and passed through the GC-MS-C-IRMS (combusted at 940 XC). In order to test the reliability of our technique we compared the _13C composition of different molecular weight organic acids (from C1 through C6) extracted individually by the traditional sealed-tube cupric oxide combustion (940 XC) method with the _13C produced by our pyrolysis technique. Our data indicate that an average 4.3. +/-0.5. (V

  3. Compartment specific importance of glutathione during abiotic and biotic stress

    Directory of Open Access Journals (Sweden)

    Bernd eZechmann

    2014-10-01

    Full Text Available The tripeptide thiol glutathione (γ-L-glutamyl-L-cysteinyl-glycine is the most important sulfur containing antioxidant in plants and essential for plant defense against abiotic and biotic stress conditions. It is involved in the detoxification of reactive oxygen species, redox signaling, the modulation of defense gene expression and important for the regulation of enzymatic activities. Even though changes in glutathione contents are well documented in plants and its roles in plant defense are well established, still too little is known about its compartment specific importance during abiotic and biotic stress conditions. Due to technical advances in the visualization of glutathione and the redox state of plants through microscopical methods some progress was made in the last few years in studying the importance of subcellular glutathione contents during stress conditions in plants. This review summarizes the data available on compartment specific importance of glutathione in the protection against abiotic and biotic stress conditions such as high light stress, exposure to cadmium, drought, and pathogen attack (Pseudomonas, Botrytis, Tobacco Mosaic Virus. The data will be discussed in connection with the subcellular accumulation of ROS during these conditions and glutathione synthesis which are both highly compartment specific (e.g. glutathione synthesis takes place in chloroplasts and the cytosol. Thus this review will reveal the compartment specific importance of glutathione during abiotic and biotic stress conditions.

  4. Abiotic and Biotic Formation of Amino Acids in the Enceladus Ocean.

    Science.gov (United States)

    Steel, Elliot L; Davila, Alfonso; McKay, Christopher P

    2017-09-01

    The active plume at Enceladus' south pole makes the indirect sampling of its global ocean possible. The partially resolved chemistry of the plume, which points to conditions that are seemingly compatible with life, has made orbital sampling missions a priority. We present a conceptual model of energy flux, hydrothermal H 2 production, and both abiotic and biotic production of amino acids. Based on the energy flux observed at the south pole and the inferred internal hydrothermal activity, we estimate an H 2 production of 0.6-34 mol/s from serpentinization, sufficient to sustain abiotic and biotic amino acid synthesis of 1.6-87 and 1-44 g/s, respectively. Two-dimensional (2D) numerical simulations of the hydrothermal vent suggest that the vent fluids could reach the ice-water boundary in less than 11-55 days for a 50 km deep ocean diluted by ambient ocean water 10 to 1. Concentrations of glycine, alanine, α-amino isobutyric acid, and glutamic acid in the plume and in the ambient ocean could all be above 0.01 μM just due to abiotic production. Biological synthesis, if occurring, could produce a maximum of 90 μM concentrations of amino acids based on a methanogenic ecosystem consuming H 2 and CO 2 . Racemization timescales in the ocean are short compared with production timescales. Thus, no enantiomeric excess is expected in the ambient ocean, and if biology is present, enantiomeric excess at the vent fluids is expected to be less than 10% in the plume. From vent H 2 concentrations of 7.8 mM (e.g., Lost City) and assuming complete H 2 use and conversion to chemical energy by methanogens, cell production is estimated. Annual biomass production in the methanogenic-based biology model is 4 × 10 4 -2 × 10 6 kg/year. This corresponds to cell concentrations ∼10 9 cells/cm 3 in the vents and ∼10 8 cells/cm 3 in the plume, and when diluted into the ambient ocean, we predict cell concentrations of 80-4250 cells/cm 3 . Key Words: Abiotic organic

  5. organic template free synthesis of zsm11 from kaolinite clay

    African Journals Online (AJOL)

    user

    diffusion assistance and tortuosity, as depicted in Figure. 1. Hongyuan and others [6] .... characterized by nearly equal peak height of Al and Si, another means to ..... method for nanocrystalline zeolite synthesis. Chemical communication.

  6. Abiotic racemization kinetics of amino acids in marine sediments

    DEFF Research Database (Denmark)

    Steen, Andrew; Jørgensen, Bo Barker; Lomstein, Bente Aagaard

    2013-01-01

    Enantiomeric ratios of amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic racemize abiotically. Based on a heating experiment, we report Arrhenius parameters...... between different amino acids or depths. These results can be used in conjunction with measurements of sediment age to predict the ratio of D:L amino acids due solely to abiotic racemization of the source material, deviations from which can indicate the abundance and turnover of active microbial...

  7. Eco-friendly Synthesis of Organics and Nanomaterials ...

    Science.gov (United States)

    The presentation summarizes our recent activity in chemical synthesis involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a variety of name reactions2 are the primary beneficiaries as exemplified by the synthesis of N-aryl azacycloalkanes, isoindoles, and dihydropyrazoles, 1,3,4-oxadiazoles, 1,3,4-thiadiazoles, 1,3-dioxanes, pyrazoles, catalyzed by basic water or polystyrene sulfonic acid (PSSA) in conjunction with microwave (MW) irradiation.2 Vitamins B1, B2, C, and tea and wine polyphenols which function both as reducing and capping agents, provide extremely simple, one-pot, green synthetic methods to bulk quantities of nanomaterials in water.3a Shape-controlled synthesis of noble nanostructures via MW-assisted spontaneous reduction of noble metal salts using sugars will be presented.3b A general method has been developed for the cross-linking reaction of poly (vinyl alcohol) (PVA) with metallic systems; bimetallic systems,3c and SWNT, MWNT, and C-60.3d The strategy is extended to the formation of biodegradable carboxymethylcellulose (CMC) composite films with noble nanometals;3e such metal decoration and alignment of carbon nanotubes in CMC is possible using MW approach3f which also enables the shape-controlled bulk synthesis of Ag and Fe nanorods in poly (ethylene glycol).3g MW hydrothermal process delivers m

  8. Recent developments on ultrasound-assisted organic synthesis in aqueous medium

    Directory of Open Access Journals (Sweden)

    Banerjee Bubun

    2017-01-01

    Full Text Available In the recent past, a number of methods were reported on the application of ultrasound in organic reactions for the synthesis of diverse organic scaffolds. On the other hand, as far as green chemistry is concerned, water is the safest of all solvents. Thus, a “strong collaboration” between ultrasonic irradiation and aqueous medium holds the key to the development of an environmentally sustainable protocol. The present review summarizes the latest developments in ultrasound-assisted and water-mediated organic synthesis reported to date.

  9. Plasmachemical synthesis of nanopowders of yttria and zirconia from dispersed water-salt-organic mixtures

    Science.gov (United States)

    Novoselov, Ivan; Karengin, Alexander; Shamanin, Igor; Alyukov, Evgeny; Gusev, Alexander

    2018-03-01

    Article represents results on theoretical and experimental research of yttria and zirconia plasmachemical synthesis in air plasma from water-salt-organic mixtures "yttrium nitrate-water-acetone" and "zirconyl nitrate-water-acetone". On the basis of thermotechnical calculations the influence of organic component on lower heat value and adiabatic combustion temperature of water-salt-organic mixtures as well as compositions of mixtures providing their energy-efficient plasma treatment were determined. The calculations found the influence of mass fraction and temperature of air plasma supporting gas on the composition of plasma treatment products. It was determined the conditions providing yttria and zirconia plasmachemical synthesis in air plasma. During experiments it was b eing carried out the plasmachemical synthesis of yttria and zirconia powders in air plasma flow from water -salt-organic mixtures. Analysis of the results for obtained powders (scanning electron microscopy, X-ray diffraction analysis, BET analysis) confirm nanostructure of yttria and zirconia.

  10. Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

    Directory of Open Access Journals (Sweden)

    Anna Kuźnik

    2017-12-01

    Full Text Available The main synthetic routes towards vinylphosphonium salts and their wide applications in organic synthesis are discussed in this review. Particular attention is paid to the use of these compounds as building blocks for the synthesis of carbo- and heterocyclic systems after their prior transformation into the corresponding phosphorus ylides, followed by the intramolecular Wittig reaction with various types of nucleophiles containing a carbonyl function in their structures.

  11. Metal–organic framework membranes: from synthesis to separation application

    KAUST Repository

    Qiu, Shilun; Xue, Ming; Zhu, Guangshan

    2014-01-01

    Metal-organic framework (MOF) materials, which are constructed from metal ions or metal ion clusters and bridging organic linkers, exhibit regular crystalline lattices with relatively well-defined pore structures and interesting properties. As a new

  12. Influence of abiotic stresses on the winter wheat sprouting plants

    Czech Academy of Sciences Publication Activity Database

    Bláha, L.; Hnilička, F.; Kadlec, P.; Smrčková-Jankovská, P.; Macháčková, Ivana; Sychrová, E.; Kohout, Ladislav

    2008-01-01

    Roč. 3, č. 3 (2008), s. 389-390 ISSN 1125-4718. [Congress of the European Society for Agronomy /10./. 15.09.2008-19.09.2008, Bologna] R&D Projects: GA MZe QF3056 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z40550506 Keywords : brassinosteroids * abiotic stress * emergency Subject RIV: CC - Organic Chemistry

  13. Synthesis of the Commercial Fragrance Compound Ethyl 6-Acetoxyhexanoate: A Multistep Ester Experiment for the Second-Year Organic Laboratory

    Science.gov (United States)

    McCullagh, James V.; Hirakis, Sophia P.

    2017-01-01

    This synthesis of ethyl 6-acetoxyhexanoate (Berryflor) is designed as an experiment for use in a second-year organic chemistry course focusing on the synthesis and reaction of esters. The compound is described as having a raspberry-like odor with jasmine and anise aspects. A two-step procedure for its synthesis beginning with inexpensive…

  14. Histidine as a catalyst in organic synthesis: A facile in situ synthesis ...

    Indian Academy of Sciences (India)

    Unknown

    They are also used in the synthesis of many nitrogen-containing biologically ... addition to hydroxylamine, results in formation of an imine, azoxy compound 15, ... GC-MS, m/z: 211 (M+), 194 (base peak); 13C NMR (DMSO-d6) δ : 31⋅14 ...

  15. Cyclodextrin-Catalyzed Organic Synthesis: Reactions, Mechanisms, and Applications

    Directory of Open Access Journals (Sweden)

    Chang Cai Bai

    2017-09-01

    Full Text Available Cyclodextrins are well-known macrocyclic oligosaccharides that consist of α-(1,4 linked glucose units and have been widely used as artificial enzymes, chiral separators, chemical sensors, and drug excipients, owing to their hydrophobic and chiral interiors. Due to their remarkable inclusion capabilities with small organic molecules, more recent interests focus on organic reactions catalyzed by cyclodextrins. This contribution outlines the current progress in cyclodextrin-catalyzed organic reactions. Particular emphases are given to the organic reaction mechanisms and their applications. In the end, the future directions of research in this field are proposed.

  16. Studies on the use of haloperoxidases in organic synthesis

    NARCIS (Netherlands)

    Franssen, M.C.R.

    1987-01-01

    The subject of this thesis is the use of haloperoxidases in synthetic organic chemistry. Haloperoxidases are enzymes capable of halogenating a variety of organic compounds. They require hydrogen peroxide and halide ions as cosubstrates. The enzymes operate under mild conditions, compared to

  17. Synthesis of refractory organic matter in the ionized gas phase of the solar nebula.

    Science.gov (United States)

    Kuga, Maïa; Marty, Bernard; Marrocchi, Yves; Tissandier, Laurent

    2015-06-09

    In the nascent solar system, primitive organic matter was a major contributor of volatile elements to planetary bodies, and could have played a key role in the development of the biosphere. However, the origin of primitive organics is poorly understood. Most scenarios advocate cold synthesis in the interstellar medium or in the outer solar system. Here, we report the synthesis of solid organics under ionizing conditions in a plasma setup from gas mixtures (H2(O)-CO-N2-noble gases) reminiscent of the protosolar nebula composition. Ionization of the gas phase was achieved at temperatures up to 1,000 K. Synthesized solid compounds share chemical and structural features with chondritic organics, and noble gases trapped during the experiments reproduce the elemental and isotopic fractionations observed in primitive organics. These results strongly suggest that both the formation of chondritic refractory organics and the trapping of noble gases took place simultaneously in the ionized areas of the protoplanetary disk, via photon- and/or electron-driven reactions and processing. Thus, synthesis of primitive organics might not have required a cold environment and could have occurred anywhere the disk is ionized, including in its warm regions. This scenario also supports N2 photodissociation as the cause of the large nitrogen isotopic range in the solar system.

  18. Synthesis and optical properties of novel organic-inorganic hybrid nanolayer structure semiconductors

    International Nuclear Information System (INIS)

    Zhang Sanjun; Lanty, Gaetan; Lauret, Jean-Sebastien; Deleporte, Emmanuelle; Audebert, Pierre; Galmiche, Laurent

    2009-01-01

    We report on the synthesis of some novel organic-inorganic hybrid 2D perovskite semiconductors (R-(CH 2 ) n NH 3 ) 2 PbX 4 . These semiconductors are self-assembled intercalation nanolayers and have a multi-quantum-well energy level structure. We systematically vary the characteristic of organic groups (R-(CH 2 ) n NH 3 + ) to study the relationship between their structures and the optical properties of (R-(CH 2 ) n NH 3 ) 2 PbX 4 . From optical absorption and photoluminescence spectroscopy experiments performed on series of samples, we find some trends of choosing the organic groups to improve the optical performance of (R-(CH 2 ) n NH 3 ) 2 PbX 4 . A new organic group, which allows synthesis of nanolayer perovskite semiconductors with quite high photoluminescence efficiency and better long-term stability, has been found.

  19. Metal organic framework synthesis in the presence of surfactants : Towards hierarchical MOFs?

    NARCIS (Netherlands)

    Seoane, B.; Dikhtiarenko, A.; Mayoral, A.; Tellez, C.; Coronas, J.; Kapteijn, F.; Gascon, J.

    2015-01-01

    The effect of synthesis pH and H2O/EtOH molar ratio on the textural properties of different aluminium trimesate metal organic frameworks (MOFs) prepared in the presence of the well-known cationic surfactant cetyltrimethylammonium bromide (CTAB) at 120 °C was studied with the purpose of obtaining a

  20. A hydrogen fuel cell for rapid, enzyme-catalysed organic synthesis with continuous monitoring.

    Science.gov (United States)

    Wan, Lei; Megarity, Clare F; Siritanaratkul, Bhavin; Armstrong, Fraser A

    2018-01-23

    A one-pot fuel cell for specific, enzyme-catalysed organic synthesis, with continuous monitoring of rate and reaction progress, combines an electrode catalysing rapid, reversible and diffusion-controlled interconversion of NADP + and NADPH with a Pt electrode catalysing 2H + /H 2 interconversion. This Communication demonstrates its performance and characteristics using the reductive amination of 2-oxoglutarate as a test system.

  1. Modulated synthesis of zirconium-metal organic framework (Zr-MOF) for hydrogen storage applications

    CSIR Research Space (South Africa)

    Ren, Jianwei

    2014-01-01

    Full Text Available A modulated synthesis of Zr-metal organic framework (Zr-MOF) with improved ease of handling and decreased reaction time is reported to yield highly crystalline Zr-MOF with well-defined octahedral shaped crystals for practical hydrogen storage...

  2. Liquid phase oxidation via heterogeneous catalysis organic synthesis and industrial applications

    CERN Document Server

    Clerici, Mario G

    2013-01-01

    Sets the stage for environmentally friendly industrial organic syntheses From basic principles to new and emerging industrial applications, this book offers comprehensive coverage of heterogeneous liquid-phase selective oxidation catalysis. It fully examines the synthesis, characterization, and application of catalytic materials for environmentally friendly organic syntheses. Readers will find coverage of all the important classes of catalysts, with an emphasis on their stability and reusability. Liquid Phase Oxidation via Heterogeneous Catalysis features contributions from an internation

  3. Synthesis and characterization of a new organic semiconductor material

    Energy Technology Data Exchange (ETDEWEB)

    Tiffour, Imane [Laboratoire de Génie Physique, Département de Physique, Université de Tiaret, Tiaret 14000 (Algeria); Faculté des Sciences et Technologies, Université Mustapha Stambouli, Mascara 29000 (Algeria); Dehbi, Abdelkader [Laboratoire de Génie Physique, Département de Physique, Université de Tiaret, Tiaret 14000 (Algeria); Mourad, Abdel-Hamid I., E-mail: ahmourad@uaeu.ac.ae [Mechanical Engineering Department, Faculty of Engineering, United Arab Emirates University, Al-Ain, P.O. Box 15551 (United Arab Emirates); Belfedal, Abdelkader [Faculté des Sciences et Technologies, Université Mustapha Stambouli, Mascara 29000 (Algeria); LPCMME, Département de Physique, Université d' Oran Es-sénia, 3100 Oran (Algeria)

    2016-08-01

    The objective of this study is to create an ideal mixture of Acetaminophen/Curcumin leading to a new and improved semiconductor material, by a study of the electrical, thermal and optical properties. This new material will be compared with existing semiconductor technology to discuss its viability within the industry. The electrical properties were investigated using complex impedance spectroscopy and optical properties were studied by means of UV-Vis spectrophotometry. The electric conductivity σ, the dielectric constant ε{sub r}, the activation energy E{sub a}, the optical transmittance T and the gap energy E{sub g} have been investigated in order to characterize our organic material. The electrical conductivity of the material is approximately 10{sup −5} S/m at room temperature, increasing the temperature causes σ to increase exponentially to approximately 10{sup −4} S/m. The activation energy obtained for the material is equal to 0.49 ± 0.02 ev. The optical absorption spectra show that the investigating material has absorbance in the visible range with a maximum wavelength (λ{sub max}) 424 nm. From analysis, the absorption spectra it was found the optical band gap equal to 2.6 ± 0.02 eV and 2.46 ± 0.02 eV for the direct and indirect transition, respectively. In general, the study shows that the developed material has characteristics of organic semiconductor material that has a promising future in the field of organic electronics and their potential applications, e.g., photovoltaic cells. - Highlights: • Development of a new organic acetaminophen/Curcumin semiconductor material. • The developed material has characteristics of an organic semiconductor. • It has electrical conductivity comparable to available organic semiconductors. • It has high optical transmittance and low permittivity/dielectric constant.

  4. Synthesis and characterization of a new organic semiconductor material

    International Nuclear Information System (INIS)

    Tiffour, Imane; Dehbi, Abdelkader; Mourad, Abdel-Hamid I.; Belfedal, Abdelkader

    2016-01-01

    The objective of this study is to create an ideal mixture of Acetaminophen/Curcumin leading to a new and improved semiconductor material, by a study of the electrical, thermal and optical properties. This new material will be compared with existing semiconductor technology to discuss its viability within the industry. The electrical properties were investigated using complex impedance spectroscopy and optical properties were studied by means of UV-Vis spectrophotometry. The electric conductivity σ, the dielectric constant ε_r, the activation energy E_a, the optical transmittance T and the gap energy E_g have been investigated in order to characterize our organic material. The electrical conductivity of the material is approximately 10"−"5 S/m at room temperature, increasing the temperature causes σ to increase exponentially to approximately 10"−"4 S/m. The activation energy obtained for the material is equal to 0.49 ± 0.02 ev. The optical absorption spectra show that the investigating material has absorbance in the visible range with a maximum wavelength (λ_m_a_x) 424 nm. From analysis, the absorption spectra it was found the optical band gap equal to 2.6 ± 0.02 eV and 2.46 ± 0.02 eV for the direct and indirect transition, respectively. In general, the study shows that the developed material has characteristics of organic semiconductor material that has a promising future in the field of organic electronics and their potential applications, e.g., photovoltaic cells. - Highlights: • Development of a new organic acetaminophen/Curcumin semiconductor material. • The developed material has characteristics of an organic semiconductor. • It has electrical conductivity comparable to available organic semiconductors. • It has high optical transmittance and low permittivity/dielectric constant.

  5. Nanogold plasmonic photocatalysis for organic synthesis and clean energy conversion.

    Science.gov (United States)

    Wang, Changlong; Astruc, Didier

    2014-01-01

    This review provides the basic concepts, an overall survey and the state-of-the art of plasmon-based nanogold photocatalysis using visible light including fundamental understanding and major applications to organic reactions and clean energy-conversion systems. First, the basic concepts of localized surface plasmon resonance (LSPR) are recalled, then the major preparation methods of AuNP-based plasmonic photocatalysts are reviewed. The major part of the review is dedicated to the latest progress in the application of nanogold plasmonic photocatalysis to organic transformations and energy conversions, and the proposed mechanisms are discussed. In conclusion, new challenges and perspectives are proposed and analyzed.

  6. Synthesis and Applications of Inorganic/Organic-Polymer Nanocomposites

    Science.gov (United States)

    Goyal, Anubha

    This research work focuses on developing new synthesis routes to fabricate polymer nanocomposites tailored towards different applications. A simple, one-step method has been devised for synthesizing free-standing, flexible metal nanoparticle-polydimethylsiloxane films. This process simplifies prevalent methods to synthesize nanocomposites, in that here nanoparticles are created in situ while curing the polymer. This route circumvents the need for pre-synthesized nanoparticles, external reducing agents and stabilizers, thereby significantly reducing processing time and cost. The resulting nanocomposite also demonstrates enhancement in mechanical and antibacterial properties, with other envisaged applications in biomedical devices and catalysis. Applying the same mechanism as that used for the formation of bulk metalsiloxane nanocomposites, metal core-siloxane shell nanoparticles and siloxane nanowires were synthesized, with octadecylsilane as the precursor and in situ formed metal nanoparticles (gold, silver) as the catalyst. This method offers some unique advantages over the previously existing methods. This is a room temperature route which does not require high temperature refluxing or the use of pre-synthesized nanoparticles. Furthermore, this synthesis process gives a control over the shape of resulting nanocomposite structures (1-D wires or 0-D spherical particles). High thermal stability of polydimethylsiloxane (PDMS) makes it viable to alternatively synthesize metal nanoparticles in the polymer matrix by thermal decomposition process. This technique is generic across a range of metals (palladium, iron, nickel) and results in nanoparticles with a very narrow size distribution. Membranes with palladium nanoparticles demonstrate catalytic activity in ethylene hydrogenation reaction. Additionally, a new nanocomposite electrode has been developed for flexible and light-weight Li-ion batteries. Flexible films were prepared by the integration of the poly

  7. Synthesis, characterization and application of an inorgano organic ...

    Indian Academy of Sciences (India)

    Its chemical stability has been assessed in various mineral acids, bases and organic solvents. Ion exchange capacity (IEC) has been determined and distribution behaviour towards several metal ions in different electrolyte solutions with varying concentrations has been studied and a few binary separations achieved.

  8. SYNTHESIS OF TETRACATIONIC ORGANIC SALT FROM 4,4 ...

    African Journals Online (AJOL)

    conventional organic solvents [4-6] and in electrochemistry [7, 8]. ... for the high solubility of the salt in water and other polar solvents such as methanol ..... Hu, L.; Xie, B.; Li, J. Efficient Baeyer-Villiger electro-oxidation of ketones with molecular.

  9. Organic Synthesis under Solvent-free Condition. An Environmentally ...

    Indian Academy of Sciences (India)

    Though it is a common practice to run the organic reactions in solvent media, the ... this concept is simple. That is, the ... to vigorous research activity and reinvestigation of known reac- tions to achieve ... experimental procedure, work up technique and saving in labour. These would be ... This is true not only of the crystals of ...

  10. Green chemistry principles in organic compound synthesis and analysis

    Directory of Open Access Journals (Sweden)

    Ruchi Verma

    2014-03-01

    Full Text Available The present review focus on various green chemistry approaches which could be utilized in the organic compounds in practical classes for undergraduate level in comparison of conventional methods. These methods avoid the usage of hazardous substances and are environmental friendly.

  11. Synthesis of silver nanocubes in a hydrophobic binary organic solvent.

    Energy Technology Data Exchange (ETDEWEB)

    Peng, S.; Sun, Y. (Center for Nanoscale Materials)

    2010-01-01

    Synthesis of metal nanoparticles with controlled shapes in hydrophobic solvents is challenging because homogeneous nucleation with high rate in these solvents is favorable for the formation of multiply twinned (MT) nanoparticles with spherical morphology. In this work, we report an inhomogeneous nucleation strategy in a binary hydrophobic solvent mediated by dimethyldistearylammonium chloride (DDAC), resulting in the coexistence of single-crystalline Ag polyhedrons and MT Ag quasi-spheres at the beginning of the reaction. In the consequent step, the MT Ag nanoparticles are selectively etched and dissolved through oxidation by NO{sub 3}{sup -} ions (from the Ag precursor, AgNO{sub 3}) with the assistance of Cl{sup -} ions (from DDAC). The dissolved Ag species are then reduced and deposited on the more stable single-crystalline polyhedrons to form Ag nanocubes. Synergy of the oxidative etching of MT particles and growth of single-crystalline particles leads to Ag nanocubes with high purity when the ripening time is long enough. For example, refluxing a mixing solvent of octyl ether and oleylamine containing AgNO{sub 3} (0.02 M) and DDAC (0.03 M) at 260 C for 1 h results in Ag nanocubes with an average edge length of 34 nm and a purity higher than 95%.

  12. Hyaluronate synthesis by synovial villi in organ culture

    International Nuclear Information System (INIS)

    Myers, S.L.; Christine, T.A.

    1983-01-01

    Individual canine synovial villi were used to establish short-term synovial organ cultures. These villi incorporated 3 H-glucosamine into highly-polymerized 3 H-hyaluronic acid ( 3 H-HA), which was the only 3 H-glycosaminoglycan identified in the culture medium. Some 3 H-HA, and larger amounts of other 3 H-glycosaminoglycans, were recovered from cultured tissues. Culture medium 3 H-HA content was proportional to the surface area of cultured villi. Organ cultures of nonvillous synovium were compared with villi; nonvillous cultures synthesized less 3 H-HA per mm2 of their synovial intimal surface than villi. These cultures complement cell culture techniques for in vitro studies of synovial lining cell function

  13. Organic superconductors: A current overview, synthesis, structure and theory

    International Nuclear Information System (INIS)

    Wang, H.H.; Beno, M.A.; Carlson, K.D.; Geiser, U.; Kini, A.M.; Williams, J.M.

    1990-01-01

    To date, four types of crystal packing motifs (β, θ, κ and α) are known to lead to superconductivity in the BEDT-TTF based materials, where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene. The syntheses, crystal structures, physical properties and band electronic structures of these materials will be reviewed. Recent progress made in the oxygen containing analogue, BEDO-TTF [bis(ethylenedioxo)tetrathiofulvalene] will be presented. The implication and future prospect of organic superconductors will be discussed

  14. Synthesis of Amino Acid Precursors with Organic Solids in Planetesimals with Liquid Water

    Science.gov (United States)

    Kebukawa, Y; Misawa, S.; Matsukuma, J.; Chan, Q. H. S.; Kobayashi, J.; Tachibana, S.; Zolensky, M. E.

    2017-01-01

    Amino acids are important ingredients of life that would have been delivered to Earth by extraterrestrial sources, e.g., comets and meteorites. Amino acids are found in aqueously altered carbonaceous chondrites in good part in the form of precursors that release amino acids after acid hydrolysis. Meanwhile, most of the organic carbon (greater than 70 weight %) in carbonaceous chondrites exists in the form of solvent insoluble organic matter (IOM) with complex macromolecular structures. Complex macromolecular organic matter can be produced by either photolysis of interstellar ices or aqueous chemistry in planetesimals. We focused on the synthesis of amino acids during aqueous alteration, and demonstrated one-pot synthesis of a complex suite of amino acids simultaneously with IOM via hydrothermal experiments simulating the aqueous processing

  15. Self-healing anticorrosive organic coating based on an encapsulated water reactive silyl ester: synthesis and proof of concept

    NARCIS (Netherlands)

    García, S.J.; Fischer, H.R.; White, P.A.; Mardel, J.; González-García, Y.; Mol, J.M.C.; Hughes, A.E.

    2011-01-01

    In this paper a self-healing anticorrosive organic coating based on an encapsulated water reactive organic agent is presented. A reactive silyl ester is proposed as a new organic reactive healing agent and its synthesis, performance, incorporation into an organic coating and evaluation of

  16. Extra-adrenal glucocorticoid synthesis: immune regulation and aspects on local organ homeostasis.

    Science.gov (United States)

    Talabér, Gergely; Jondal, Mikael; Okret, Sam

    2013-11-05

    Systemic glucocorticoids (GCs) mainly originate from de novo synthesis in the adrenal cortex under the control of the hypothalamus-pituitary-adrenal (HPA)-axis. However, research during the last 1-2 decades has revealed that additional organs express the necessary enzymes and have the capacity for de novo synthesis of biologically active GCs. This includes the thymus, intestine, skin and the brain. Recent research has also revealed that locally synthesized GCs most likely act in a paracrine or autocrine manner and have significant physiological roles in local homeostasis, cell development and immune cell activation. In this review, we summarize the nature, regulation and known physiological roles of extra-adrenal GC synthesis. We specifically focus on the thymus in which GC production (by both developing thymocytes and epithelial cells) has a role in the maintenance of proper immunological function. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Toward an experimental synthesis of the chondritic insoluble organic matter

    Science.gov (United States)

    Biron, Kasia; Derenne, Sylvie; Robert, FrançOis; Rouzaud, Jean-NoëL.

    2015-08-01

    Based on the statistical model proposed for the molecular structure of the insoluble organic matter (IOM) isolated from the Murchison meteorite, it was recently proposed that, in the solar T-Tauri disk regions where (photo)dissociation of gaseous molecules takes place, aromatics result from the cyclization/aromatization of short aliphatics. This hypothesis is tested in this study, with n-alkanes being submitted to high-frequency discharge at low pressure. The contamination issue was eliminated using deuterated precursor. IOM was formed and studied using solid-state nuclear magnetic resonance, pyrolysis coupled to gas chromatography and mass spectrometry, RuO4 oxidation, and high-resolution transmission electron microscopy. It exhibits numerous similarities at the molecular level with the hydrocarbon backbone of the natural IOM, reinforcing the idea that the initial precursors of the IOM were originally chains in the gas. Moreover, a fine comparison between the chemical structure of several meteorite IOM suggests either that (i) the meteorite IOMs share a common precursor standing for the synthetic IOM or that (ii) the slight differences between the meteorite IOMs reflect differences in their environment at the time of their formation i.e., related to plasma temperature that, in turn, dictates the dissociation-recombination rates of organic fragments.

  18. Structural versatility of Metal-organic frameworks: Synthesis and Characterization

    KAUST Repository

    Alsadun, Norah S.

    2017-05-01

    Metal-Organic Frameworks (MOFs), an emerging class of porous crystalline materials, have shown promising properties for diverse applications such as catalysis, gas storage and separation. The high degree of tunability of MOFs vs other solid materials enable the assembly of advanced materials with fascinating properties for specific applications. Nevertheless, the precise control in the construction of MOFs at the molecular level remains challenging. Particularly, the formation of pre-targeted multi-nuclear Molecular Building Block (MBB) precursors to unveil materials with targeted structural characteristics is captivating. The aim of my master project in the continuous quest of the group of Prof. Eddaoudi in exploring different synthetic pathways to control the assembly of Rare Earth (RE) based MOF. After giving a general overview about MOFs, I will discuss in this thesis the results of my work on the use of tri-topic oriented organic carboxylate building units with the aim to explore the assembly/construction of new porous RE based MOFs. In chapter 2 will discuss the assembly of 3-c linkers with RE metals was then evaluated based on symmetry and angularity of the three connected linkers. The focus of chapter 3 is cerium based MOFs and heterometallic system, based on 3-c ligands with different length and symmetry. Overall, the incompatibility of 3-c ligands with the 12-c cuo MBB did not allow to any formation of higher neuclearity (˃6), but it has resulted in affecting the connectivity of the cluster.

  19. Facile synthesis of organically capped PbS nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nejo, Ayorinde O.; Nejo, Adeola A.; Pullabhotla, Rajasekhar V.S.R. [Department of Chemistry, University of Zululand, Private Bag X1001, Kwadlangezwa (South Africa); Revaprasadu, Neerish, E-mail: nrevapra@pan.uzulu.ac.za [Department of Chemistry, University of Zululand, Private Bag X1001, Kwadlangezwa (South Africa)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer Hexadecylamine and tri-n-octylphosphine oxide capped PbS nanoparticles have been synthesized. Black-Right-Pointing-Pointer By varying the reaction conditions various morphologies were formed. Black-Right-Pointing-Pointer The formation of the anisotropic particles is due to different growth mechanisms. - Abstract: PbS nanocubes and nanorods were successfully synthesized through a facile route using hexadecylamine (HDA) and tri-n-octylphosphine oxide (TOPO) as surfactants. The structure and morphology of the as-prepared PbS nanocrystals were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM. The morphology of the PbS was influenced by the variation in lead source and organic surfactant. Particles in the shape of spheres, perfect cubes and rods were obtained by variation in reaction conditions. A possible growth mechanism to explain the formation of these PbS nanocubes and nanorods is also discussed.

  20. Aging changes of molecular synthesis in the respiratory organs as revealed by microscopic radioautography

    International Nuclear Information System (INIS)

    Nagata, T.

    2001-01-01

    For the purpose of elucidating the aging changes of macromolecular synthesis such as DNA, RNA, proteins, glycoproteins, glycides and lipids in various organ systems of experimental animals and men, we have studied respiratory organs of aging mice as a series of systematic studies using light and electron microscopic radioautography in various organ systems after incorporations with macromolecular precursors. The experimental animals mainly used were dd Y strain mice at various aging groups from embryo to postnatal day 1 and 3, weeks 1 and 2, months 1, 2, 6, 12 up to 2 year senescent stages. The animals were injected with such macromolecular precursors as 3 H - thymidine for DNA, 3 H-uridine for RNA, 3 H-leucine for proteins, 35 SO 4 for glycoproteins. The results demonstrated that these precursors were incorporated into various cell types in the lungs and tracheas at various ages from perinatal to juvenile, mature and senescent stages showing specific patterns of macromolecular synthesis. It is concluded that these specific pattern of macromolecular synthesis in respective cell types demonstrated the organ specificity of aging. (author)

  1. Titania may produce abiotic oxygen atmospheres on habitable exoplanets

    OpenAIRE

    Norio Narita; Takafumi Enomoto; Shigeyuki Masaoka; Nobuhiko Kusakabe

    2015-01-01

    The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet ...

  2. Timing of RNA synthesis for sperimiogenesis in organ cultures of Drosophila melanogaster teste

    Energy Technology Data Exchange (ETDEWEB)

    Gould-Somero, M; Holland, L

    1974-01-01

    A method for the organ culture of Drosophila testes is described which supports the differentiation of primary spermatocytes through the meiotic divisions to elongating spermatids. Autoradiographic and inhibitor studies reveal no evidence for RNA synthesis by developing spermatids of Drosophila melanogaster; most, if not all, of the RNA required for the differentiation and elongation of sperm is synthesized earlier in the primary spermatocytes. Primary spermatocytes will differentiate into elongating spermatids in organ culture, despite severe (96 to 98%) inhibition of /sup 3/H-uridine incorporation into RNA effected by 50 ..mu..g/ml 3'-deoxyadenosine. Protein synthesis in spermatids continues to be active in the presence of 3'-deoxyadenosine, but that in growing spermatocytes is severely inhibited.

  3. An improved synthesis of pentacene: rapid access to a benchmark organic semiconductor.

    Science.gov (United States)

    Pramanik, Chandrani; Miller, Glen P

    2012-04-20

    Pentacene is an organic semiconductor used in a variety of thin-film organic electronic devices. Although at least six separate syntheses of pentacene are known (two from dihydropentacenes, two from 6,13-pentacenedione and two from 6,13-dihydro-6,13-dihydroxypentacene), none is ideal and several utilize elevated temperatures that may facilitate the oxidation of pentacene as it is produced. Here, we present a fast (-2 min of reaction time), simple, high-yielding (≥ 90%), low temperature synthesis of pentacene from readily available 6,13-dihydro-6,13-dihydroxypentacene. Further, we discuss the mechanism of this highly efficient reaction. With this improved synthesis, researchers gain rapid, affordable access to high purity pentacene in excellent yield and without the need for a time consuming sublimation.

  4. An Improved Synthesis of Pentacene: Rapid Access to a Benchmark Organic Semiconductor

    Directory of Open Access Journals (Sweden)

    Glen P. Miller

    2012-04-01

    Full Text Available Pentacene is an organic semiconductor used in a variety of thin-film organic electronic devices. Although at least six separate syntheses of pentacene are known (two from dihydropentacenes, two from 6,13-pentacenedione and two from 6,13-dihydro-6,13-dihydroxypentacene, none is ideal and several utilize elevated temperatures that may facilitate the oxidation of pentacene as it is produced. Here, we present a fast (~2 min of reaction time, simple, high-yielding (≥90%, low temperature synthesis of pentacene from readily available 6,13-dihydro-6,13-dihydroxypentacene. Further, we discuss the mechanism of this highly efficient reaction. With this improved synthesis, researchers gain rapid, affordable access to high purity pentacene in excellent yield and without the need for a time consuming sublimation.

  5. KH in Paraffin - KH(P): A Useful Base for Organic Synthesis

    Science.gov (United States)

    Taber, Douglass F.; Nelson, Christopher G.

    2011-01-01

    The preparation of KH as a one:one homogenate with paraffin, termed KH(P), is reported. KH(P), a solid at room temperature, is stable without special handling. On suspension in THF with a phosphonium salt, KH(P) rapidly generates the ylide. Wittig condensation with aromatic, aliphatic and α, β-unsaturated aldehydes proceeds with high Z-selectivity. KH(P) should be a generally useful base for organic synthesis. PMID:17081034

  6. Benefits of Using a Problem-Solving Scaffold for Teaching and Learning Synthesis in Undergraduate Organic Chemistry I

    Science.gov (United States)

    Sloop, Joseph C.; Tsoi, Mai Yin; Coppock, Patrick

    2016-01-01

    A problem-solving scaffold approach to synthesis was developed and implemented in two intervention sections of Chemistry 2211K (Organic Chemistry I) at Georgia Gwinnett College (GGC). A third section of Chemistry 2211K at GGC served as the control group for the experiment. Synthesis problems for chapter quizzes and the final examination were…

  7. Metal Organic Frameworks: Explorations and Design Strategies for MOF Synthesis

    KAUST Repository

    AbdulHalim, Rasha

    2016-11-27

    Metal-Organic Frameworks (MOFs) represent an emerging new class of functional crystalline solid-state materials. In the early discovery of this now rapidly growing class of materials significant challenges were often encountered. However, MOFs today, with its vast structural modularity, reflected by the huge library of the available chemical building blocks, and exceptional controlled porosity, stand as the most promising candidate to address many of the overbearing societal challenges pertaining to energy and environmental sustainability. A variety of design strategies have been enumerated in the literature which rely on the use of predesigned building blocks paving the way towards potentially more predictable structures. The two major design strategies presented in this work are the molecular building block (MBB) and supermolecular building block (SBB) -based approaches for the rationale assembly of functional MOF materials with the desired structural features. In this context, we targeted two highly connected MOF platforms, namely rht-MOF and shp-MOF. These two MOF platforms are classified based on their topology, defined as the underlying connectivity of their respective net, as edge transitive binodal nets; shp being (4,12)-connected net and rht being (3,24)-connected net. These highly connected nets were deliberately targeted due to the limited number of possible nets for connecting their associated basic building units. Two highly porous materials were designed and successfully constructed; namely Y-shp-MOF-5 and rht-MOF-10. The Y-shp-MOF-5 features a phenomenal water stability with an exquisite behavior when exposed to water, positioning this microporous material as the best adsorbent for moisture control applications. The shp-MOF platform proved to be modular to ligand functionalization and thus imparting significant behavioral changes when hydrophilic and hydrophobic functionalized ligands were introduced on the resultant MOF. On the other hand, rht

  8. A Versatile Route for the Synthesis of Nickel Oxide Nanostructures Without Organics at Low Temperature

    Directory of Open Access Journals (Sweden)

    Shah MA

    2008-01-01

    Full Text Available AbstractNickel oxide nanoparticles and nanoflowers have been synthesized by a soft reaction of nickel powder and water without organics at 100 °C. The mechanism for the formation of nanostructures is briefly described in accordance with decomposition of metal with water giving out hydrogen. The structure, morphology, and the crystalline phase of resulting nanostructures have been characterized by various techniques. Compared with other methods, the present method is simple, fast, economical, template-free, and without organics. In addition, the approach is nontoxic without producing hazardous waste and could be expanded to provide a general and convenient strategy for the synthesis of nanostructures to other functional nanomaterials.

  9. Abiotic degradation of plastic films

    Science.gov (United States)

    Ángeles-López, Y. G.; Gutiérrez-Mayen, A. M.; Velasco-Pérez, M.; Beltrán-Villavicencio, M.; Vázquez-Morillas, A.; Cano-Blanco, M.

    2017-01-01

    Degradable plastics have been promoted as an option to mitigate the environmental impacts of plastic waste. However, there is no certainty about its degradability under different environmental conditions. The effect of accelerated weathering (AW), natural weathering (NW) and thermal oxidation (TO) on different plastics (high density polyethylene, HDPE; oxodegradable high density polyethylene, HDPE-oxo; compostable plastic, Ecovio ® metalized polypropylene, PP; and oxodegradable metalized polypropylene, PP-oxo) was studied. Plastics films were exposed to AW per 110 hours; to NW per 90 days; and to TO per 30 days. Plastic films exposed to AW and NW showed a general loss on mechanical properties. The highest reduction in elongation at break on AW occurred to HDPE-oxo (from 400.4% to 20.9%) and was higher than 90% for HDPE, HDPE-oxo, Ecovio ® and PP-oxo in NW. No substantial evidence of degradation was found on plastics exposed to TO. Oxo-plastics showed higher degradation rates than their conventional counterparts, and the compostable plastic was resistant to degradation in the studied abiotic conditions. This study shows that degradation of plastics in real life conditions will vary depending in both, their composition and the environment.

  10. Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites.

    Science.gov (United States)

    Vollmer, Christian; Kepaptsoglou, Demie; Leitner, Jan; Busemann, Henner; Spring, Nicole H; Ramasse, Quentin M; Hoppe, Peter; Nittler, Larry R

    2014-10-28

    Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight (15)N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C-O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C-O bonding environments and nanoglobular organics with dominant aromatic and C-N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid.

  11. Design, Synthesis and Characterization of Functional Metal-Organic Framework Materials

    KAUST Repository

    Alamer, Badriah

    2015-06-01

    Over the past few decades, vast majority of industrial and academic research throughout the world has witnessed the emergence of materials that can serve as ideal candidates for potential utility in desired applications, and these materials are known as Metal Organic Framework (MOFs). This exceptional new family of porous materials is fabricated by linkage of metal ions or clusters and organic linkers via strong bonds. MOFs have been awarded with remarkable interest and widely studied due to their inherent structural methodology (e.g. use of various metals, expanded library of organic building blocks with different geometry and functionality particularly frameworks designed from carboxylate organic linkers) and unquestionably unique structural and chemical features for many practical applications. (i.e. gas storage/separation, catalysis, drug delivery etc). Simply, metal organic frameworks epitomize the beauty of porous chemical structures. From a design perspective, the introduction of the Molecular Building Block (MBB) approach is actively being pursued pathway by researchers toward the construction of MOFs by employing inorganic building blocks and organic linkers and taking advantage of not only their multiple coordination modes and geometries but also the way in which they are reticulated to generate final framework. In this thesis, research studies will be directed toward (i) the investigation of the relationship between experimental parameters and synthesis of well-known fcu –MOF, (ii) rational design and synthesis of new rare earth (RE) based MOFs, (ii) isoreticular materials based on particular MBB ([M3O(RCO2)6]), M= p-and d-block metals, and (iv) zeolite- like metal organic framework assembled from single-metal ion based MBB ([MN2(CO2)4]) via 2-, 3-,and 4-connected organic linkers. Consequently, the porosity, chemical and thermal stability, and gas sorption properties will be evaluated and detailed.

  12. Arbuscular mycorrhizal fungal responses to abiotic stresses: A review.

    Science.gov (United States)

    Lenoir, Ingrid; Fontaine, Joël; Lounès-Hadj Sahraoui, Anissa

    2016-03-01

    The majority of plants live in close collaboration with a diversity of soil organisms among which arbuscular mycorrhizal fungi (AMF) play an essential role. Mycorrhizal symbioses contribute to plant growth and plant protection against various environmental stresses. Whereas the resistance mechanisms induced in mycorrhizal plants after exposure to abiotic stresses, such as drought, salinity and pollution, are well documented, the knowledge about the stress tolerance mechanisms implemented by the AMF themselves is limited. This review provides an overview of the impacts of various abiotic stresses (pollution, salinity, drought, extreme temperatures, CO2, calcareous, acidity) on biodiversity, abundance and development of AMF and examines the morphological, biochemical and molecular mechanisms implemented by AMF to survive in the presence of these stresses. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms

    Energy Technology Data Exchange (ETDEWEB)

    Uma Suganya, K.S. [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Govindaraju, K., E-mail: govindtu@gmail.com [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Ganesh Kumar, V.; Stalin Dhas, T.; Karthick, V. [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Singaravelu, G. [Nanoscience Division, Department of Zoology, Thiruvalluvar University, Vellore 632115 (India); Elanchezhiyan, M. [Department of Microbiology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai 600113 (India)

    2015-02-01

    Biofunctionalized gold nanoparticles (AuNPs) play an important role in design and development of nanomedicine. Synthesis of AuNPs from biogenic materials is environmentally benign and possesses high bacterial inhibition and bactericidal properties. In the present study, blue green alga Spirulina platensis protein mediated synthesis of AuNPs and its antibacterial activity against Gram positive bacteria is discussed. AuNPs were characterized using Ultraviolet–visible (UV–vis) spectroscopy, Fluorescence spectroscopy, Fourier Transform-Infrared (FTIR) spectroscopy, Raman spectroscopy, High Resolution-Transmission Electron Microscopy (HR-TEM) and Energy Dispersive X-ray analysis (EDAX). Stable, well defined AuNPs of smaller and uniform shape with an average size of ∼ 5 nm were obtained. The antibacterial efficacy of protein functionalized AuNPs were tested against Gram positive organisms Bacillus subtilis and Staphylococcus aureus. - Highlights: • Size controlled synthesis of gold nanoparticles from blue green alga Spirulina platensis • Stability of gold nanoparticles at different temperatures • Potent antibacterial efficacy against Gram positive organisms.

  14. Structure-directing effects of ionic liquids in the ionothermal synthesis of metal-organic frameworks.

    Science.gov (United States)

    Vaid, Thomas P; Kelley, Steven P; Rogers, Robin D

    2017-07-01

    Traditional synthesis of metal-organic frameworks (MOFs) involves the reaction of a metal-containing precursor with an organic linker in an organic solvent at an elevated temperature, in what is termed a 'solvothermal' reaction. More recently, many examples have been reported of MOF synthesis in ionic liquids (ILs), rather than an organic solvent, in 'ionothermal' reactions. The high concentration of both cations and anions in an ionic liquid allows for the formation of new MOF structures in which the IL cation or anion or both are incorporated into the MOF. Most commonly, the IL cation is included in the open cavities of the MOF, countering the anionic charge of the MOF framework itself and acting as a template around which the MOF structure forms. Ionic liquids can also serve other structure-directing roles, for example, when an IL containing a single enantiomer of a chiral anion leads to a homochiral MOF, even though the IL anion is not itself incorporated into the MOF. A comprehensive review of ionothermal syntheses of MOFs, and the structure-directing effects of the ILs, is given.

  15. Structure-directing effects of ionic liquids in the ionothermal synthesis of metal–organic frameworks

    Directory of Open Access Journals (Sweden)

    Thomas P. Vaid

    2017-07-01

    Full Text Available Traditional synthesis of metal–organic frameworks (MOFs involves the reaction of a metal-containing precursor with an organic linker in an organic solvent at an elevated temperature, in what is termed a `solvothermal' reaction. More recently, many examples have been reported of MOF synthesis in ionic liquids (ILs, rather than an organic solvent, in `ionothermal' reactions. The high concentration of both cations and anions in an ionic liquid allows for the formation of new MOF structures in which the IL cation or anion or both are incorporated into the MOF. Most commonly, the IL cation is included in the open cavities of the MOF, countering the anionic charge of the MOF framework itself and acting as a template around which the MOF structure forms. Ionic liquids can also serve other structure-directing roles, for example, when an IL containing a single enantiomer of a chiral anion leads to a homochiral MOF, even though the IL anion is not itself incorporated into the MOF. A comprehensive review of ionothermal syntheses of MOFs, and the structure-directing effects of the ILs, is given.

  16. Synthesis and optical properties of novel organic-inorganic hybrid nanolayer structure semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Sanjun; Lanty, Gaetan; Lauret, Jean-Sebastien [Laboratoire de Photonique Quantique et Moleculaire de l' Ecole Normale Superieure de Cachan, 61 avenue du President Wilson, 94235 Cachan (France); Deleporte, Emmanuelle, E-mail: Emmanuelle.Deleporte@lpqm.ens-cachan.fr [Laboratoire de Photonique Quantique et Moleculaire de l' Ecole Normale Superieure de Cachan, 61 avenue du President Wilson, 94235 Cachan (France); Audebert, Pierre; Galmiche, Laurent [Laboratoire de Photophysique et Photochimie Supramoleculaires et Macromoleculaires de l' Ecole Normale Superieure de Cachan, 61 avenue du President Wilson, 94235 Cachan (France)

    2009-06-15

    We report on the synthesis of some novel organic-inorganic hybrid 2D perovskite semiconductors (R-(CH{sub 2}){sub n}NH{sub 3}){sub 2}PbX{sub 4}. These semiconductors are self-assembled intercalation nanolayers and have a multi-quantum-well energy level structure. We systematically vary the characteristic of organic groups (R-(CH{sub 2}){sub n}NH{sub 3}{sup +}) to study the relationship between their structures and the optical properties of (R-(CH{sub 2}){sub n}NH{sub 3}){sub 2}PbX{sub 4}. From optical absorption and photoluminescence spectroscopy experiments performed on series of samples, we find some trends of choosing the organic groups to improve the optical performance of (R-(CH{sub 2}){sub n}NH{sub 3}){sub 2}PbX{sub 4}. A new organic group, which allows synthesis of nanolayer perovskite semiconductors with quite high photoluminescence efficiency and better long-term stability, has been found.

  17. Changes in biotic and abiotic processes following mangrove clearing

    Science.gov (United States)

    Granek, Elise; Ruttenberg, Benjamin I.

    2008-12-01

    Mangrove forests, important tropical coastal habitats, are in decline worldwide primarily due to removal by humans. Changes to mangrove systems can alter ecosystem properties through direct effects on abiotic factors such as temperature, light and nutrient supply or through changes in biotic factors such as primary productivity or species composition. Despite the importance of mangroves as transitional habitats between land and sea, little research has examined changes that occur when they are cleared. We examined changes in a number of biotic and abiotic factors following the anthropogenic removal of red mangroves ( Rhizophora mangle) in the Panamanian Caribbean, including algal biomass, algal diversity, algal grazing rates, light penetration, temperature, sedimentation rates and sediment organic content. In this first study examining multiple ecosystem-level effects of mangrove disturbance, we found that areas cleared of mangroves had higher algal biomass and richness than intact mangrove areas. This increase in algal biomass and richness was likely due to changes in abiotic factors (e.g. light intensity, temperature), but not biotic factors (fish herbivory). Additionally the algal and cyanobacterial genera dominating mangrove-cleared areas were rare in intact mangroves and included a number of genera that compete with coral for space on reefs. Interestingly, sedimentation rates did not differ between intact and cleared areas, but the sediments that accumulated in intact mangroves had higher organic content. These findings are the first to demonstrate that anthropogenic clearing of mangroves changes multiple biotic and abiotic processes in mangrove forests and that some of these changes may influence adjacent habitats such as coral reefs and seagrass beds. Additional research is needed to further explore the community and ecosystem-level effects of mangrove clearing and their influence on adjacent habitats, but it is clear that mangrove conservation is an

  18. Direct Synthesis of 7 nm Thick Zinc(II)-Benzimidazole-Acetate Metal-Organic Framework Nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Feng; Kumar, Prashant; Xu, Wenqian; Mkhoyan, K. Andre; Tsapatsis, Michael

    2018-01-09

    Two-dimensional metal-organic frameworks (MOFs) are promising candidates for high performance gas sepa-ration membranes. Currently, MOF nanosheets are mostly fabricated through delamination of layered MOFs, which often re-sults in a low yield of intact free-standing nanosheets. In this work, we present a direct synthesis method for zinc(II)-benzimidazole-acetate (Zn(Bim)OAc) MOF nanosheets. The obtained nanosheets have a lateral dimension of 600 nm when synthesized at room temperature. By adjusting the synthesis temperature, the morphology of obtained nanosheets can be readily tuned from nanosheets to nanobelts. A thickness of 7 nm is determined for Zn(Bim)OAc using high-angle annular dark-field scanning transmission electron microscopy, which makes these nanosheets promising building blocks of gas sepa-ration membranes.

  19. Abscisic Acid and Abiotic Stress Signaling

    OpenAIRE

    Tuteja, Narendra

    2007-01-01

    Abiotic stress is severe environmental stress, which impairs crop production on irrigated land worldwide. Overall, the susceptibility or tolerance to the stress in plants is a coordinated action of multiple stress responsive genes, which also cross-talk with other components of stress signal transduction pathways. Plant responses to abiotic stress can be determined by the severity of the stress and by the metabolic status of the plant. Abscisic acid (ABA) is a phytohormone critical for plant ...

  20. Synthesis and identification of organic components of 'Red Oil' (contact research)

    International Nuclear Information System (INIS)

    Miyata, Teijiro; Takada, Junichi; Nakagiri, Naotaka; Koike, Tadao; Tsukamoto, Michio; Watanabe, Koji; Nishio, Gunji

    1999-05-01

    To make clear the organic constituents of the energetic material described as 'Red Oil', laboratory studies were made on the synthesis and identification of chemical constituents of the materials obtained in the synthesis. In the studies, the synthesis was made using a variety of solvent systems (100%TBP/HNO 3 , 100%TBP/HNO 3 /U, 30%TBP/70%n-Dodecane/HNO 3 , 30%TBP/70%n-Dodecane/HNO 3 /U) with an experimental apparatus (1.0 liter under) under conditions, e.g., a temperature range 129 - 192degC and a reaction time 90 - 270 minutes, and GC and GC/MS techniques were mainly used for the identification. A GC analysis showed that the 'Red Oil' prepared from a solvent system (30%TBP/70%n-Dodecane/HNO 3 ) should comprised more than 150 degraded products, 94 products of which were identified purely by a GC/MS technique. Major components found, except for TBP and n-Dodecane being used as the starting materials, were mono- and di-nitro compounds of them, dodecanones, n-butyl nitrate, DBP and MBP. The quantitative analysis of gases formed in the 'Red Oil' synthesis experiments showed that they consisted of various compounds, the order of decreasing content in volume % were NO 2 (23 - 50), CO 2 (17 - 34), N 2 O(5.5 - 15), N 2 (4.3 - 12), CO(4 - 12), NO(1.5 - 8), and hydrocarbons (0.7 - 1.2), and that no detectable presence of O 2 and N 2 . Most of the components in the distillated volatiles collected in the condenser were n-botyl nitrate, but n-butanol were found in relatively small quantities. No significant effect of uranyl nitrate was found on the organic constituents in the 'Red Oil' synthesized. (author)

  1. Synthesis and identification of organic components of `Red Oil` (contact research)

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Teijiro [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Takada, Junichi; Nakagiri, Naotaka; Koike, Tadao; Tsukamoto, Michio; Watanabe, Koji; Nishio, Gunji

    1999-05-01

    To make clear the organic constituents of the energetic material described as `Red Oil`, laboratory studies were made on the synthesis and identification of chemical constituents of the materials obtained in the synthesis. In the studies, the synthesis was made using a variety of solvent systems (100%TBP/HNO{sub 3}, 100%TBP/HNO{sub 3}/U, 30%TBP/70%n-Dodecane/HNO{sub 3}, 30%TBP/70%n-Dodecane/HNO{sub 3}/U) with an experimental apparatus (1.0 liter under) under conditions, e.g., a temperature range 129 - 192degC and a reaction time 90 - 270 minutes, and GC and GC/MS techniques were mainly used for the identification. A GC analysis showed that the `Red Oil` prepared from a solvent system (30%TBP/70%n-Dodecane/HNO{sub 3}) should comprised more than 150 degraded products, 94 products of which were identified purely by a GC/MS technique. Major components found, except for TBP and n-Dodecane being used as the starting materials, were mono- and di-nitro compounds of them, dodecanones, n-butyl nitrate, DBP and MBP. The quantitative analysis of gases formed in the `Red Oil` synthesis experiments showed that they consisted of various compounds, the order of decreasing content in volume % were NO{sub 2} (23 - 50), CO{sub 2} (17 - 34), N{sub 2}O(5.5 - 15), N{sub 2}(4.3 - 12), CO(4 - 12), NO(1.5 - 8), and hydrocarbons (0.7 - 1.2), and that no detectable presence of O{sub 2} and N{sub 2}. Most of the components in the distillated volatiles collected in the condenser were n-botyl nitrate, but n-butanol were found in relatively small quantities. No significant effect of uranyl nitrate was found on the organic constituents in the `Red Oil` synthesized. (author)

  2. Metal-organic frameworks: structure, properties, methods of synthesis and characterization

    International Nuclear Information System (INIS)

    Butova, V V; Soldatov, M A; Guda, A A; Lomachenko, K A; Lamberti, C

    2016-01-01

    This review deals with key methods of synthesis and characterization of metal-organic frameworks (MOFs). The modular structure affords a wide variety of MOFs with different active metal sites and organic linkers. These compounds represent a new stage of development of porous materials in which the pore size and the active site structure can be modified within wide limits. The set of experimental methods considered in this review is sufficient for studying the short-range and long-range order of the MOF crystal structure, determining the morphology of samples and elucidating the processes that occur at the active metal site in the course of chemical reactions. The interest in metal-organic frameworks results, first of all, from their numerous possible applications, ranging from gas separation and storage to chemical reactions within the pores. The bibliography includes 362 references

  3. A Research Module for the Organic Chemistry Laboratory: Multistep Synthesis of a Fluorous Dye Molecule.

    Science.gov (United States)

    Slade, Michael C; Raker, Jeffrey R; Kobilka, Brandon; Pohl, Nicola L B

    2014-01-14

    A multi-session research-like module has been developed for use in the undergraduate organic teaching laboratory curriculum. Students are tasked with planning and executing the synthesis of a novel fluorous dye molecule and using it to explore a fluorous affinity chromatography separation technique, which is the first implementation of this technique in a teaching laboratory. Key elements of the project include gradually introducing students to the use of the chemical literature to facilitate their searching, as well as deliberate constraints designed to force them to think critically about reaction design and optimization in organic chemistry. The project also introduces students to some advanced laboratory practices such as Schlenk techniques, degassing of reaction mixtures, affinity chromatography, and microwave-assisted chemistry. This provides students a teaching laboratory experience that closely mirrors authentic synthetic organic chemistry practice in laboratories throughout the world.

  4. Advances in Electrocatalysis for Energy Conversion and Synthesis of Organic Molecules.

    Science.gov (United States)

    Holade, Yaovi; Servat, Karine; Tingry, Sophie; Napporn, Teko W; Remita, Hynd; Cornu, David; Kokoh, K Boniface

    2017-10-06

    Ubiquitous electrochemistry is expected to play a major role for reliable energy supply as well as for production of sustainable fuels and chemicals. The fundamental understanding of organics-based electrocatalysis in alkaline media at the solid-liquid interface involves complex mechanisms and performance descriptors (from the electrolyte and reaction intermediates), which undermine the roads towards advance and breakthroughs. Here, we review and diagnose recently designed strategies for the electrochemical conversion of organics into electricity and/or higher-value chemicals. To tune the mysterious workings of nanocatalysts in electrochemical devices, we examine the guiding principles by which the performance of a particular electrode material is governed, thus highlighting various tactics for the development of synthesis methods for nanomaterials with specific properties. We end by examining the production of chemicals by using electrochemical methods, from selective oxidation to reduction reactions. The intricate relationship between electrode and selectivity encourages both of the communities of electrocatalysis and organic synthesis to move forward together toward the renaissance of electrosynthesis methods. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Scalable synthesis and post-modification of a mesoporous metal-organic framework called NU-1000.

    Science.gov (United States)

    Wang, Timothy C; Vermeulen, Nicolaas A; Kim, In Soo; Martinson, Alex B F; Stoddart, J Fraser; Hupp, Joseph T; Farha, Omar K

    2016-01-01

    The synthesis of NU-1000, a highly robust mesoporous (containing pores >2 nm) metal-organic framework (MOF), can be conducted efficiently on a multigram scale from inexpensive starting materials. Tetrabromopyrene and (4-(ethoxycarbonyl)phenyl)boronic acid can easily be coupled to prepare the requisite organic strut with four metal-binding sites in the form of four carboxylic acids, while zirconyl chloride octahydrate is used as a precursor for the well-defined metal oxide clusters. NU-1000 has been reported as an excellent candidate for the separation of gases, and it is a versatile scaffold for heterogeneous catalysis. In particular, it is ideal for the catalytic deactivation of nerve agents, and it shows great promise as a new generic platform for a wide range of applications. Multiple post-synthetic modification protocols have been developed using NU-1000 as the parent material, making it a potentially useful scaffold for several catalytic applications. The procedure for the preparation of NU-1000 can be scaled up reliably, and it is suitable for the production of 50 g of the tetracarboxylic acid containing organic linker and 200 mg-2.5 g of NU-1000. The entire synthesis is performed without purification by column chromatography and can be completed within 10 d.

  6. Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

    Science.gov (United States)

    Kunoh, Tatsuki; Hashimoto, Hideki; McFarlane, Ian R.; Hayashi, Naoaki; Suzuki, Tomoko; Taketa, Eisuke; Tamura, Katsunori; Takano, Mikio; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun

    2016-01-01

    Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths. PMID:27271677

  7. Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

    Directory of Open Access Journals (Sweden)

    Tatsuki Kunoh

    2016-06-01

    Full Text Available Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II to Fe(III and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II concentrations, Fe(III precipitates visibly formed immediately after addition of Fe(II to the medium, suggesting prompt abiotic oxidation of Fe(II to Fe(III. Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter, while those in the Fe(III medium were composed of large, aggregated particles (≥3 µm diameter with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved of Fe encrustation of the Leptothrix sheaths.

  8. Induction of abiotic stress tolerance in plants by endophytic microbes.

    Science.gov (United States)

    Lata, R; Chowdhury, S; Gond, S K; White, J F

    2018-04-01

    Endophytes are micro-organisms including bacteria and fungi that survive within healthy plant tissues and promote plant growth under stress. This review focuses on the potential of endophytic microbes that induce abiotic stress tolerance in plants. How endophytes promote plant growth under stressful conditions, like drought and heat, high salinity and poor nutrient availability will be discussed. The molecular mechanisms for increasing stress tolerance in plants by endophytes include induction of plant stress genes as well as biomolecules like reactive oxygen species scavengers. This review may help in the development of biotechnological applications of endophytic microbes in plant growth promotion and crop improvement under abiotic stress conditions. Increasing human populations demand more crop yield for food security while crop production is adversely affected by abiotic stresses like drought, salinity and high temperature. Development of stress tolerance in plants is a strategy to cope with the negative effects of adverse environmental conditions. Endophytes are well recognized for plant growth promotion and production of natural compounds. The property of endophytes to induce stress tolerance in plants can be applied to increase crop yields. With this review, we intend to promote application of endophytes in biotechnology and genetic engineering for the development of stress-tolerant plants. © 2018 The Society for Applied Microbiology.

  9. Titania may produce abiotic oxygen atmospheres on habitable exoplanets.

    Science.gov (United States)

    Narita, Norio; Enomoto, Takafumi; Masaoka, Shigeyuki; Kusakabe, Nobuhiko

    2015-09-10

    The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet (NUV) lights on the surface of exoplanets. Titania works as a photocatalyst to dissociate liquid water in this process. This mechanism offers a different source of a possibility of abiotic oxygen in atmospheres of exoplanets from previously considered photodissociation of water vapor in upper atmospheres by extreme ultraviolet (XUV) light. Our order-of-magnitude estimation shows that possible amounts of oxygen produced by this abiotic mechanism can be comparable with or even more than that in the atmosphere of the current Earth, depending on the amount of active surface area for this mechanism. We conclude that titania may act as a potential source of false signs of life on habitable exoplanets.

  10. A short designed semi-aromatic organic nanotube – synthesis, chiroptical characterization, and host properties

    DEFF Research Database (Denmark)

    Wixe, Torbjörn; Christensen, Niels Johan; Lidin, Sven

    2014-01-01

    to molecular dynamics simulations in chloroform). The synthesis of the tube, a heptamer, is based on a series of Friedländer condensations and the use of pyrido[3,2-d]pyrimidine units as masked 2-amino aldehydes, as a general means to propagate organic tubular structures and the introduction of a methoxy group...... for modification toward solubility and functionalization are described. The electronic CD spectra of the tube and molecular intermediates are correlated with theoretical spectra calculated with time-dependent density functional theory to characterize the chirality of the tube. Both experimental (NMR...

  11. Synthesis and characterization of organic-inorganic hybrids formed between conducting polymers and crystalline antimonic acid

    Directory of Open Access Journals (Sweden)

    Beleze Fábio A.

    2001-01-01

    Full Text Available In this paper we report the synthesis and characterization of novel organic-inorganic hybrid materials between the crystalline antimonic acid (CAA and two conductive polymers: polypyrrole and polyaniline. The hybrids were obtained by in situ oxidative polymerization of monomers by the Sb(V present in the pyrochlore-like CAA structure. The materials were characterized by infrared and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, CHN elemental analysis and electronic paramagnetic resonance spectroscopy. The results showed that both polymers were formed in their oxidized form, with the CAA structure acting as a counter anion.

  12. Applications of Continuous-Flow Photochemistry in Organic Synthesis, Material Science, and Water Treatment.

    Science.gov (United States)

    Cambié, Dario; Bottecchia, Cecilia; Straathof, Natan J W; Hessel, Volker; Noël, Timothy

    2016-09-14

    Continuous-flow photochemistry in microreactors receives a lot of attention from researchers in academia and industry as this technology provides reduced reaction times, higher selectivities, straightforward scalability, and the possibility to safely use hazardous intermediates and gaseous reactants. In this review, an up-to-date overview is given of photochemical transformations in continuous-flow reactors, including applications in organic synthesis, material science, and water treatment. In addition, the advantages of continuous-flow photochemistry are pointed out and a thorough comparison with batch processing is presented.

  13. Zeolite-like metal–organic frameworks (ZMOFs): design, synthesis, and properties

    KAUST Repository

    Eddaoudi, Mohamed; Sava, Dorina F.; Eubank, Jarrod F.; Adil, Karim; Guillerm, Vincent

    2014-01-01

    This review highlights various design and synthesis approaches toward the construction of ZMOFs, which are metal–organic frameworks (MOFs) with topologies and, in some cases, features akin to traditional inorganic zeolites. The interest in this unique subset of MOFs is correlated with their exceptional characteristics arising from the periodic pore systems and distinctive cage-like cavities, in conjunction with modular intra- and/or extra-framework components, which ultimately allow for tailoring of the pore size, pore shape, and/or properties towards specific applications.

  14. Zeolite-like metal–organic frameworks (ZMOFs): design, synthesis, and properties

    KAUST Repository

    Eddaoudi, Mohamed

    2014-10-24

    This review highlights various design and synthesis approaches toward the construction of ZMOFs, which are metal–organic frameworks (MOFs) with topologies and, in some cases, features akin to traditional inorganic zeolites. The interest in this unique subset of MOFs is correlated with their exceptional characteristics arising from the periodic pore systems and distinctive cage-like cavities, in conjunction with modular intra- and/or extra-framework components, which ultimately allow for tailoring of the pore size, pore shape, and/or properties towards specific applications.

  15. Parameters Affecting the Synthesis of (Z)-3-hexen-1-yl acetate by Transesterifacation in Organic Solvent

    International Nuclear Information System (INIS)

    Liaquat, M.; Mehmood, T.; Khan, S. U.; Ahmed, Z.; Saeed, M.; Aslam, S.; Khan, J.; Ali, N.; Jahangir, M.; Nawaz, M.

    2015-01-01

    (Z)-3-hexen-1-yl esters are important green top-note components of food flavors and fragrances. Crude acetone powders extracted lipases from five plant seedlings of rapeseed, wheat, barley, linseed and maize were investigated for their use in the synthesis of flavor esters with vinyl acetate by transesterification in organic solvents. Rape seedlings showed the highest degree of (Z)-3-hexen-1-yl acetate synthesis with a yield of 76 percentage in 72 h. Rape seedling was chosen as promising biocatalyst to evaluate the effects of some of reaction parameters on (Z)-3-hexen-1-yl acetate synthesis using vinyl acetate and (Z)-3-hexen-1-ol at 40 Degree C in n-hexane with 50 g/L enzyme as catalyst. Acetonitrile proved distinctly superior solvent. The percent remaining activity relative to fresh seedlings powders was highest in wheat and barley. Highest ester yield of 80 percentage was obtained with 0.8 M of substrate concentrations within 48 h. Crude rapeseed lipase afforded a conversion 93 percentage of ethyl alcohol. Higher ester yield was achieved within first 24 h with added molecular. The crude rape seedlings lipase is low cost yet effective, showed potential for the production of green note esters industrially. (author)

  16. Protein synthesis evaluation in brain and other organs in human by PET

    International Nuclear Information System (INIS)

    Bustany, P.; Comar, D.

    1985-01-01

    The choice of treatment in diseases of the nervous system cannot be based only on symptomatology, but on a presumed underlying pathological state. These pathological states often involve direct modifications of neuronal metabolism. Two areas of cellular biochemistry can be studied in vivo in humans: 1) glucose or oxygen consumption which is mainly responsible for energy and lipid metabolism. 2) amino acid metabolism, which is involved in protein and neurotransmitter synthesis. Here the authors examine protein synthesis, which is the basis of cellular integrity and tissue structure. Study of protein synthesis (PS) by positron emission tomography (PET) is governed by specific requirements dictated by 1) the metabolic pathways we want to explore (the fate of the tracer directly influences the analysis of the results); 2) The construction and validation of a mathematical model to be applied to the computerized images; and 3) the human pathology being studied. The timing of scanning and the experimental protocol must include in their conception some physiological constraints such as volume of organs, rapidity of biological phenomena, etc. All these steps are detailed in the following paragraphs

  17. Arctic Synthesis Collaboratory: A Virtual Organization for Transformative Research and Education on a Changing Arctic

    Science.gov (United States)

    Warnick, W. K.; Wiggins, H. V.; Hinzman, L.; Holland, M.; Murray, M. S.; Vörösmarty, C.; Loring, A. J.

    2008-12-01

    About the Arctic Synthesis Collaboratory The Arctic Synthesis Collaboratory concept, developed through a series of NSF-funded workshops and town hall meetings, is envisioned as a cyber-enabled, technical, organizational, and social-synthesis framework to foster: • Interactions among interdisciplinary experts and stakeholders • Integrated data analysis and modeling activities • Training and development of the arctic science community • Delivery of outreach, education, and policy-relevant resources Scientific Rationale The rapid rate of arctic change and our incomplete understanding of the arctic system present the arctic community with a grand scientific challenge and three related issues. First, a wealth of observations now exists as disconnected data holdings, which must be coordinated and synthesized to fully detect and assess arctic change. Second, despite great strides in the development of arctic system simulations, we still have incomplete capabilities for modeling and predicting the behavior of the system as a whole. Third, policy-makers, stakeholders, and the public are increasingly making demands of the science community for forecasts and guidance in mitigation and adaptation strategies. Collaboratory Components The Arctic Synthesis Collaboratory is organized around four integrated functions that will be established virtually as a distributed set of activities, but also with the advantage of existing facilities that could sponsor some of the identified activities. Community Network "Meeting Grounds:" The Collaboratory will link distributed individuals, organizations, and activities to enable collaboration and foster new research initiatives. Specific activities could include: an expert directory, social networking services, and virtual and face-to-face meetings. Data Integration, Synthesis, and Modeling Activities: The Collaboratory will utilize appropriate tools to enable the combination of data and models. Specific activities could include: a web

  18. Benign by design: catalyst-free in-water, on-water green chemical methodologies in organic synthesis

    Science.gov (United States)

    The development of organic synthesis under sustainable conditions is a primary goal of practicing green chemists who want to prevent pollution and design safer pathways. Although, it is challenging to avoid the use of catalysts, or solvents in all the organic reactions but progre...

  19. Saccharin Derivative Synthesis via [1,3] Thermal Sigmatropic Rearrangement: A Multistep Organic Chemistry Experiment for Undergraduate Students

    Science.gov (United States)

    Fonseca, Custódia S. C.

    2016-01-01

    Saccharin (1,2-benzisothiazole-3-one 1,1-dioxide) is an artificial sweetener used in the food industry. It is a cheap and easily available organic compound that may be used in organic chemistry laboratory classes for the synthesis of related heterocyclic compounds and as a derivatizing agent. In this work, saccharin is used as a starting material…

  20. Integration of Fermentation and Organic Synthesis: Studies of Roquefortine C and Biosynthetic Derivatives

    Science.gov (United States)

    Gober, Claire Marie

    Roquefortine C is one of the most ubiquitous indoline alkaloids of fungal origin. It has been isolated from over 30 different species of Penicillium fungi and has garnered attention in recent years for its role as a biosynthetic precursor to the triazaspirocyclic natural products glandicoline B, meleagrin, and oxaline. The triazaspirocyclic motif, which encompasses three nitrogen atoms attached to one quaternary carbon forming a spirocyclic scaffold, is a unique chemical moiety that has been shown to impart a wide array of biological activity, from anti-bacterial activity and antiproliferative activity against cancer cell lines to anti-biofouling against marine organisms. Despite the promise of these compounds in the pharmaceutical and materials industries, few syntheses of triazaspirocycles exist in the literature. The biosynthesis of roquefortine C-derived triazaspirocycles, however, provides inspiration for the synthesis of these compounds, namely through a nitrone-promoted transannular rearrangement. This type of internal rearrangement has never been carried out synthetically and would provide an efficient stereoselective synthesis of triazaspirocycles. This work encompasses efforts towards elucidating the biosynthetic pathway of roquefortine C-derived triazaspirocycles as well as synthetic efforts towards the construction of triazaspirocycles. Chapter 1 will discuss a large-scale fermentation procedure for the production of roquefortine C from Penicillium crustosum. Chapters 2 and 3 explore (through enzymatic and synthetic means, respectively) the formation of the key indoline nitrone moiety required for the proposed transannular rearrangement. Finally, chapter 4 will discuss synthetic efforts towards the synthesis of triazaspirocycles. This work has considerably enhanced our understanding of the roquefortine C biosynthetic pathway and the unique chemistry of this natural product, and our efforts towards the synthesis of triazaspirocycles will facilitate the

  1. Sustainable Utility of Magnetically Recyclable Nano-Catalysts in Water: Applications in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Manoj B. Gawande

    2013-10-01

    Full Text Available Magnetically recyclable nano-catalysts and their use in aqueous media is a perfect combination for the development of greener sustainable methodologies in organic synthesis. It is well established that magnetically separable nano-catalysts avoid waste of catalysts or reagents and it is possible to recover >95% of catalysts, which is again recyclable for subsequent use. Water is the ideal medium to perform the chemical reactions with magnetically recyclable nano-catalysts, as this combination adds tremendous value to the overall benign reaction process development. In this review, we highlight recent developments inthe use of water and magnetically recyclable nano-catalysts (W-MRNs for a variety of organic reactions namely hydrogenation, condensation, oxidation, and Suzuki–Miyaura cross-coupling reactions, among others.

  2. Synthesis of Pd and Rh metal nanoparticles in the interlayer space of organically modified montmorillonite

    International Nuclear Information System (INIS)

    Patel, Hasmukh A.; Bajaj, Hari C.; Jasra, Raksh Vir

    2008-01-01

    This study reports the synthesis of palladium and rhodium metal nanoparticles supported on montmorillonite (MMT) and partially organically modified MMT (POMM) using tetraamine palladium and hexaamine rhodium complex as precursor for palladium and rhodium respectively. The synthesized nanoparticles were characterized by powder X-ray diffraction PXRD and TEM. The PXRD study shows characteristic crystallographic planes for Pd and Rh metal and confirm the formation of metal nanoparticles in MMT and POMM. The TEM images reveal the effect of organic modification of MMT on decreasing particle size of Pd and Rh metal. The Pd and Rh metal nanoparticles are agglomerated in pristine MMT while nanoparticles are well dispersed in POMM. ICP-AES analysis was carried out to estimate quantitative amount of Pd and Rh metal in MMT and POMM

  3. Thiophene fused azacoronenes: regioselective synthesis, self organization, charge transport, and its incorporation in conjugated polymers

    Science.gov (United States)

    Liu, Yi; He, Bo

    2015-09-15

    A regioselective synthesis of an azacoronene fused with two peripheral thiophene groups has been realized through a concise synthetic route. The resulting thienoazacoronene (TAC) derivatives show high degree of self-organization in solution, in single crystals, in the bulk, and in spuncast thin films. Spuncast thin film field-effect transistors of the TACs exhibited mobilities up to 0.028 cm.sup.2V.sup.-1 S.sup.-1, which is among the top field effect mobilities for solution processed discotic materials. Organic photovoltaic devices using TAC-containing conjugated polymers as the donor material exhibited a high open-circuit voltage of 0.89 V, which was ascribable to TAC's low-lying highest occupied molecular orbital energy level.

  4. Nanoscale luminescent lanthanide-based metal–organic frameworks: properties, synthesis, and applications

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Dongqin; Song, Yonghai; Wang, Li, E-mail: lwanggroup@aliyun.com [Jiangxi Normal University, Key Laboratory of Functional Small Organic Molecule, Ministry of Education, Key Laboratory of Chemical Biology, Jiangxi Province, College of Chemistry and Chemical Engineering (China)

    2015-07-15

    Nanoscale luminescent lanthanide-based metal–organic frameworks (NLLn-MOFs) possess superior optical and physical properties such as higher luminescent lifetime, quantum yield, high stability, high surface area, high agent loading, and intrinsic biodegradability, and therefore are regarded as a novel generation of luminescent material compared with bulk lanthanide-based metal–organic frameworks (Ln-MOFs). Traditional luminescent Ln-MOFs have been well studied; however, NLLn-MOFs taking the advantages of nanomaterials have attracted extensive investigations for applications in optical imaging in living cells, light-harvesting, and sensing. In this review, we provide a survey of the latest progresses made in developing NLLn-MOFs, which contains the fundamental optical features, synthesis, and their potential applications. Finally, the future prospects and challenges of the rapidly growing field are summarized.

  5. ROS-mediated abiotic stress-induced programmed cell death in plants

    NARCIS (Netherlands)

    Petrov, Veselin; Hille, Jacob; Mueller-Rober, Bernd; Gechev, Tsanko S.

    2015-01-01

    During the course of their ontogenesis plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms

  6. Synthesis of novel inorganic-organic hybrid materials for simultaneous adsorption of metal ions and organic molecules in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Xinliang [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China); Li, Yanfeng, E-mail: liyf@lzu.edu.cn [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China); Yu, Cui; Ma, Yingxia; Yang, Liuqing; Hu, Huaiyuan [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China)

    2011-12-30

    Highlights: Black-Right-Pointing-Pointer Novel hybrid materials were synthesized and employed in the absorption of heavy metal and organic pollutants. Black-Right-Pointing-Pointer A novel method for amphiphilic adsorbent material synthesis was first reported in this paper. Black-Right-Pointing-Pointer The adsorbent material showed excellent adsorption capacity to Pb(II) and phenol. - Abstract: In this paper, atom transfer radical polymerization (ATRP) and radical grafting polymerization were combined to synthesize a novel amphiphilic hybrid material, meanwhile, the amphiphilic hybrid material was employed in the absorption of heavy metal and organic pollutants. After the formation of attapulgite (ATP) ATRP initiator, ATRP block copolymers of styrene (St) and divinylbenzene (DVB) were grafted from it as ATP-P(S-b-DVB). Then radical polymerization of acrylonitrile (AN) was carried out with pendent double bonds in the DVD units successfully, finally we got the inorganic-organic hybrid materials ATP-P(S-b-DVB-g-AN). A novel amphiphilic hybrid material ATP-P(S-b-DVB-g-AO) (ASDO) was obtained after transforming acrylonitrile (AN) units into acrylamide oxime (AO) as hydrophilic segment. The adsorption capacity of ASDO for Pb(II) could achieve 131.6 mg/g, and the maximum removal capacity of ASDO towards phenol was found to be 18.18 mg/g in the case of monolayer adsorption at 30 Degree-Sign C. The optimum pH was 5 for both lead and phenol adsorption. The adsorption kinetic suited pseudo-second-order equation and the equilibrium fitted the Freundlich model very well under optimal conditions. At the same time FT-IR, TEM and TGA were also used to study its structure and property.

  7. Synthesis of Perylene Imide Diones as Platforms for the Development of Pyrazine Based Organic Semiconductors.

    Science.gov (United States)

    de Echegaray, Paula; Mancheño, María J; Arrechea-Marcos, Iratxe; Juárez, Rafael; López-Espejo, Guzmán; López Navarrete, J Teodomiro; Ramos, María Mar; Seoane, Carlos; Ortiz, Rocío Ponce; Segura, José L

    2016-11-18

    There is a great interest in peryleneimide (PI)-containing compounds given their unique combination of good electron accepting ability, high abosorption in the visible region, and outstanding chemical, thermal, and photochemical stabilities. Thus, herein we report the synthesis of perylene imide derivatives endowed with a 1,2-diketone functionality (PIDs) as efficient intermediates to easily access peryleneimide (PI)-containing organic semiconductors with enhanced absorption cross-section for the design of tunable semiconductor organic materials. Three processable organic molecular semiconductors containing thiophene and terthiophene moieties, PITa, PITb, and PITT, have been prepared from the novel PIDs. The tendency of these semiconductors for molecular aggregation have been investigated by NMR spectroscopy and supported by quantum chemical calculations. 2D NMR experiments and theoretical calculations point to an antiparallel π-stacking interaction as the most stable conformation in the aggregates. Investigation of the optical and electrochemical properties of the materials is also reported and analyzed in combination with DFT calculations. Although the derivatives presented here show modest electron mobilities of ∼10 -4 cm 2 V -1 s -1 , these preliminary studies of their performance in organic field effect transistors (OFETs) indicate the potential of these new building blocks as n-type semiconductors.

  8. Synthesis and Surface-Specific Analysis of Molecular Constituents Relevant to Biogenic Secondary Organic Aerosol Material

    Science.gov (United States)

    Be, A. G.; Upshur, M. A.; Chase, H. M.; Geiger, F.; Thomson, R. J.

    2017-12-01

    Secondary organic aerosol (SOA) particles formed from the oxidation of biogenic volatile organic compounds (BVOCs) remain a principal, yet elusive, class of airborne particulate matter that impacts the Earth's radiation budget. Given the characteristic molecular complexity comprising biogenic SOA particles, chemical information selective to the gas-aerosol interface may be valuable in the investigation of such systems, as surface considerations likely dictate the phenomena driving particle evolution mechanisms and climate effects. In particular, cloud activation processes may be parameterized using the surface tension depression that coincides with partitioning of surface-active organic species to the gas-droplet interface. However, the extent to which surface chemical processes, such as cloud droplet condensation, are influenced by the chemical structure and reactivity of individual surface-active molecules in SOA particles is largely unknown. We seek to study terpene-derived organic species relevant to the surfaces of biogenic SOA particles via synthesis of putative oxidation products followed by analysis using surface-selective physicochemical measurements. Using dynamic surface tension measurements, considerable differences are observed in the surface tension depression of aqueous pendant droplets that contain synthetically prepared ozonolysis products derived from abundant terpene precursors. Furthermore, sum frequency generation spectroscopy is utilized for comparison of the surface vibrational spectral responses of synthesized reference compounds with those observed for laboratory aerosol toward probing the surface composition of SOA material. Such ongoing findings highlight the underlying importance of molecular structure and reactivity when considering the surface chemistry of biogenic terpene-derived atmospheric aerosols.

  9. Progammed synthesis of magnetic mesoporous silica coated carbon nanotubes for organic pollutant adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Yue; Zhang, Min, E-mail: congmingyang123@163.com; Xia, Peixiong; Wang, Linlin; Zheng, Jing; Li, Weizhen; Xu, Jingli, E-mail: xujingli@sues.edu.cn

    2016-05-15

    Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis method and were characterized by TEM, XRD, FTIR, TGA, N{sub 2} adsorption–desorption and VSM. The well-designed mesoporous magnetic nanotubes had a large specific area, a highly open mesoporous structure and high magnetization. Firstly, SiO{sub 2}-coated maghemite/CNTs nanoparticles (CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites) were synthesized by the combination of high temperature decomposition process and an sol–gel method, in which the iron acetylacetonate as well as TEOS acted as the precursor for maghemite and SiO{sub 2}, respectively. The CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites revealed a core–shell structure, Then, CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was obtained by extracting cetyltrimethylammonium bromide (CTAB) via an ion-exchange procedure. The resulting composites show not only a magnetic response to an externally applied magnetic field, but also can be a good adsorbent for the organic pollutant in the ambient temperature. - Graphical abstract: Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis, which can be a good adsorbent for the organic pollutant in the ambient temperature. - Highlights: • The surface of CNTs/Fe{sub 3}O{sub 4} is hydrophilic, which facilitates the silica coating. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was synthesized by a facile method. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} can be a good adsorbent for the organic pollutant.

  10. Synthesis of organic liquids/geo-polymer composites for the immobilization of nuclear wastes

    International Nuclear Information System (INIS)

    Cantarel, Vincent

    2016-01-01

    This work is included in the management of radioactive organic liquids research field. The process is based on an emulsification of organic liquid in an alkali silicate solution allowing the synthesis of a geo-polymer matrix. The first part of this work consists in carrying out a screening on different organic liquids. A model system representative of the various oils and a geo-polymer reference formulation are then defined. The second part deals with the structuration of the organic liquid/geo-polymer structuration, from the mixture of the reactants to the final material. It aims at determining the phenomena allowing the synthesis of a homogeneous composite. The last two parts aim at characterizing the composite by studying its structure (chemical structure, porosity of the geo-polymer and dispersion of the oil) and its properties with respect to the application to the immobilization of radioactive waste. Unlike calcium silicate-based cementitious matrices, the structure of the geo-polymer is not affected by the chemical nature of the organic liquids. Only acid oils inhibit or slow down the geo-polymerization reaction. In order to obtain a homogeneous material, the presence of surfactant molecules is necessary. The emulsion stabilization mechanism at the base of the process is relying on a synergy between the surfactant molecules and the aluminosilicate particles present in the geo-polymer paste. The kinetics (chemical and mechanical) of the geo-polymerization are not impacted by the presence of oil or surfactants. Only an increase in the viscoelastic moduli and the elastic character of the pastes can be observed. This difference in rheological behavior is mainly due to the presence of surfactant. The structure of the matrix is identical to that of a pure geo-polymer of the same formulation. The organic liquid is dispersed in spherical inclusions whose radius is between 5 and 15 μm. These droplets are separated from each other, and from the environment by the

  11. Soft plasma processing of organic nanowires: a route for the fabrication of 1D organic heterostructures and the template synthesis of inorganic 1D nanostructures.

    Science.gov (United States)

    Alcaire, Maria; Sanchez-Valencia, Juan R; Aparicio, Francisco J; Saghi, Zineb; Gonzalez-Gonzalez, Juan C; Barranco, Angel; Zian, Youssef Oulad; Gonzalez-Elipe, Agustin R; Midgley, Paul; Espinos, Juan P; Groening, Pierangelo; Borras, Ana

    2011-11-01

    Hierarchical (branched) and hybrid metal-NPs/organic supported NWs are fabricated through controlled plasma processing of metalloporphyrin, metallophthalocyanine and perylene nanowires. The procedure is also applied for the development of a general template route for the synthesis of supported metal and metal oxide nanowires.

  12. Room-temperature sol–gel synthesis of organic ligand-capped ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zobel, Mirijam, E-mail: mirijam.zobel@fau.de; Chatterjee, Haimantee [Friedrich-Alexander University Erlangen-Nürnberg (FAU), Department of Physics, Lehrstuhl für Kristallographie und Strukturphysik (Germany); Matveeva, Galina; Kolb, Ute [Johannes Gutenberg-Universität, Institut für Physikalische Chemie (Germany); Neder, Reinhard B., E-mail: reinhard.neder@fau.de [Friedrich-Alexander University Erlangen-Nürnberg (FAU), Department of Physics, Lehrstuhl für Kristallographie und Strukturphysik (Germany)

    2015-05-15

    Powders of zinc oxide nanoparticles with individual particle sizes below 10 nm in diameter are readily produced in base-induced sol–gel processes from ethanolic solutions of zinc acetate dihydrate. These particles are covered with acetate molecules and without further stabilization, they grow when stored as a powder. Here, we present three organic ligands, which reproducibly stabilize individual particle sizes <5 nm within the agglomerated powders for extended periods of time, up to months. Citric acid and 1,5-diphenyl-1,3,5-pentanetrione result in average diameters of 3 nm, whereas dimethyl-L-tartrate stabilizes 2.1 nm. X-ray diffraction and pair distribution function analysis were used to investigate the structural properties of the particles. TEM data confirm the individual particle size and crystallinity and show that the particles are agglomerated without structural coherence. Besides the introduction of these novel ligands for ZnO nanoparticles, we investigated, in particular, the influence of each synthesis step onto the final nanoparticle size in the powder. Previous studies often reported the employed synthesis parameters, but did not motivate the reasoning for their choice based on detailed experimental observations. Herein, we regard separately the steps of (i) the synthesis of the colloids, (ii) their precipitation, and (iii) the drying of the resulting gel to understand the role of the ligands therein. ZnO particles only covered with acetate grow to 5 nm during the drying process, whereas particles with any of the additional ligands retain their colloidal size of 2–3 nm. This clearly shows the efficient binding and effect of the presented ligands.

  13. Indices, multispecies and synthesis descriptors in benthic assessments: Intertidal organic enrichment from oyster farming

    Science.gov (United States)

    Quintino, Victor; Azevedo, Ana; Magalhães, Luísa; Sampaio, Leandro; Freitas, Rosa; Rodrigues, Ana Maria; Elliott, Michael

    2012-09-01

    Intertidal off-bottom oyster culture is shown to cause organic enrichment of the shore and although there are two stressors of interest (the presence of a structure, the trestles, and also the sediment and organic waste from the oysters), these can be separated and their relative impacts determined using an appropriate nested experimental design and data treatments. Although no artificial food sources are involved, the oysters feeding activity and intensity of culture enhances biodeposition and significantly increases the sediment fines content and total organic matter. This in general impoverished the benthic community in culture areas rather than a species succession with the installation of opportunists or a resulting increase in the abundance and biomass of benthic species; the findings can be a direct consequence of the intertidal situation which is less-amenable recruitment of species more common to the subtidal environment. Thus the most appropriate biological descriptors to diagnose the effects associated with the organic enrichment were the multispecies abundance data as well as the primary biological variables species richness and abundance. The effects were however spatially and statistically significantly confined to the area located directly underneath the culture bags compared to the corridors located between the trestles, which do not show such enrichment effects. Synthesis biotic indices were much less effective to diagnose the benthic alterations associated with this organic enrichment. These results show that special attention must be paid when using indices in areas where the organic enrichment induces an impoverishment of the benthic community but not necessarily a species replacement with the installation of opportunists.

  14. Synthesis of NMP, a Fluoxetine (Prozac) Precursor, in the Introductory Organic Laboratory

    Science.gov (United States)

    Perrine, Daniel M.; Sabanayagam, Nathan R.; Reynolds, Kristy J.

    1998-10-01

    A synthesis of the immediate precursor of the widely used antidepressant fluoxetine (Prozac) is described. The procedure is short, safe, and simple enough to serve as a laboratory exercise for undergraduate students in the second semester of introductory organic chemistry and is one which will be particularly interesting to those planning a career in the health sciences. The compound synthesized is (°)-N,N-dimethyl-3-(p-trifluoromethylphenoxy)-3-phenylpropylamine, or "N-methyl Prozac" (NMP). The synthesis of NMP requires one two-hour period and a second three-hour period. In the first period, a common Mannich base, 3-dimethylaminopropiophenone, is reduced with sodium borohydride to form (°)-3-dimethylamino-1-phenylpropanol. In the second period, potassium t-butoxide is used to couple (°)-3-dimethylamino-1-phenylpropanol with p-chlorotrifluoromethylbenzene to form NMP, which is isolated as its oxalate salt. All processes use equipment and materials that are inexpensive and readily available in most undergraduate laboratories. Detailed physical data are given on NMP, including high-field DEPT 13C NMR.

  15. MICOS and phospholipid transfer by Ups2-Mdm35 organize membrane lipid synthesis in mitochondria.

    Science.gov (United States)

    Aaltonen, Mari J; Friedman, Jonathan R; Osman, Christof; Salin, Bénédicte; di Rago, Jean-Paul; Nunnari, Jodi; Langer, Thomas; Tatsuta, Takashi

    2016-06-06

    Mitochondria exert critical functions in cellular lipid metabolism and promote the synthesis of major constituents of cellular membranes, such as phosphatidylethanolamine (PE) and phosphatidylcholine. Here, we demonstrate that the phosphatidylserine decarboxylase Psd1, located in the inner mitochondrial membrane, promotes mitochondrial PE synthesis via two pathways. First, Ups2-Mdm35 complexes (SLMO2-TRIAP1 in humans) serve as phosphatidylserine (PS)-specific lipid transfer proteins in the mitochondrial intermembrane space, allowing formation of PE by Psd1 in the inner membrane. Second, Psd1 decarboxylates PS in the outer membrane in trans, independently of PS transfer by Ups2-Mdm35. This latter pathway requires close apposition between both mitochondrial membranes and the mitochondrial contact site and cristae organizing system (MICOS). In MICOS-deficient cells, limiting PS transfer by Ups2-Mdm35 and reducing mitochondrial PE accumulation preserves mitochondrial respiration and cristae formation. These results link mitochondrial PE metabolism to MICOS, combining functions in protein and lipid homeostasis to preserve mitochondrial structure and function. © 2016 Aaltonen et al.

  16. Synthesis and bioimaging of biodegradable red fluorescent organic nanoparticles with aggregation-induced emission characteristics.

    Science.gov (United States)

    Xu, Dazhuang; Zou, Hui; Liu, Meiying; Tian, Jianwen; Huang, Hongye; Wan, Qing; Dai, Yanfeng; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

    2017-12-15

    Fluorescent organic nanoparticles (FONs) with aggregation-induced emission (AIE) features have recently emerged as promising fluorescent probes for biomedical applications owing to their excellent optical properties, designability and biocompatibility. Significant progress has been made recently for synthesis and biomedical applications of these AIE-active FONs. However, only very limited reports have demonstrated the fabrication of biodegradable AIE-active FONs with red fluorescence emission. In this study, a novel strategy has been developed for the preparation of biodegradable AIE-active polyurethanes (PUs) through a two-step polymerization, in which the diisocyanate-terminated polyethylene glycol (NCO-PEG-NCO) was synthesized and subsequently conjugated with diamine-containing AIE dye (NH 2 -Phe-NH 2 ). The successful synthesis of AIE-active Phe-PEG 2000 PUs is evidenced by a series of characterization techniques. Because of the formation of AIE-active amphiphilic PUs, the final copolymers can self-assemble into spherical nanoparticles, which exhibit strong luminescence and high water dispersion. The biological evaluation results suggest that the AIE-active Phe-PEG 2000 FONs possess low toxicity and desirable cell permeability. Therefore, we anticipate that these AIE-active FONs with biodegradable potential will trigger much research enthusiasm and effort toward the creation of new AIE-active materials with improved properties for various biomedical applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Synthesis of metal-organic framework films by pore diffusion method

    Science.gov (United States)

    Murayama, Naohiro; Nishimura, Yuki; Kajiro, Hiroshi; Kishida, Satoru; Kinoshita, Kentaro; Tottori Univ Team; Nippon Steel; Sumitomo Metal Co. Collaboration; Tottori Integrated Frontier Resaerch Center (Tifrec) Collaboration; Tottori University Electronic Display Resaerch Center (Tedrec) Collaboration

    Metal-organic frameworks (MOFs) presents high controllability in designing the nano-scale pore, and this enable molecular storages, catalysts, gas sensors, gas separation membranes, and electronic devices for next-generation. Therefore, a simple method for film synthesis of MOFs compared with conventional methods [1] is strongly required. In this paper, we provide pore diffusion method, in which a substrate containing constituent metals of MOF is inserted in solution that includes only linker molecules of MOF. As a result, 2D growth of MOF was effectively enhanced, and the formation of flat and dense MOF films was attained. The growth time, t, dependence of film thickness, d, can be expressed by the relation of d = Aln(t + 1) + B, where A and B are constants. It means that ionized coppers diffuse through the pores of MOFs and the synthesis reaction proceeds at the MOF/solvent interface. We demonstrated the fabrication of a HKUST-1/Cu-TPA hetero structure by synthesizing a Cu-TPA film continuously after the growth of a HKUST-1 film on the CuOx substrate.

  18. Synthesis of Organic Matter of Prebiotic Chemistry at the Protoplanetary Disc

    Science.gov (United States)

    Snytnikov, Valeriy; Stoynovskaya, Olga; Rudina, Nina

    We have carried out scanning electron microscopic examination of CM carbonaceous chondrites meteorites Migey, Murchison, Staroe Boriskino aged more than 4.56 billion years (about 50 million years from the beginning of the formation of the Solar system). Our study confirmed the conclusion of Rozanov, Hoover and other researchers about the presence of microfossils of bacterial origin in the matrix of all these meteorites. Since the time of the Solar system formation is 60 - 100 million years, the primary biocenosis emerged in the protoplanetary disc of the Solar system before meteorites or simultaneously with them. It means that prebiological processes and RNA world appeared even earlier in the circumsolar protoplanetary disc. Most likely, this appearance of prebiotic chemistry takes place nowday in massive and medium-massive discs of the observed young stellar objects (YSO) class 0 and I. The timescale of the transition from chemical to biological evolution took less than 50 million years for the Solar system. Further evolution of individual biocenosis in a protoplanetary disc associated with varying physico-chemical conditions during the formation of the Solar system bodies. Biocenosis on these bodies could remove or develop under the influence of many cosmic factors and geological processes in the case of Earth. To complete the primary biosphere formation in short evolution time - millions of years - requires highly efficient chemical syntheses. In industrial chemistry for the efficient synthesis of ammonia, hydrogen cyanide, methanol and other organic species, that are the precursors to obtain prebiotic compounds, catalytic reactors of high pressure are used. Thus (1) necessary amount of the proper catalyst in (2) high pressure areas of the disc can trigger these intense syntheses. The disc contains the solids with the size from nanoparticle to pebble. Iron and magnesium is catalytically active ingredient for such solids. The puzzle is a way to provide hydrogen

  19. Abiotic drivers of Chihuahuan Desert plant communities

    Science.gov (United States)

    Laura Marie Ladwig

    2014-01-01

    Within grasslands, precipitation, fire, nitrogen (N) addition, and extreme temperatures influence community composition and ecosystem function. The differential influences of these abiotic factors on Chihuahuan Desert grassland communities was examined within the Sevilleta National Wildlife Refuge, located in central New Mexico, U.S.A. Although fire is a natural...

  20. Single step synthesis and organization of gold colloids assisted by copolymer templates

    International Nuclear Information System (INIS)

    Sarrazin, Aurélien; Gontier, Arthur; Plaud, Alexandre; Béal, Jérémie; Yockell-Lelièvre, Hélène; Bijeon, Jean-Louis; Plain, Jérôme; Adam, Pierre-Michel; Maurer, Thomas

    2014-01-01

    We report here an original single-step process for the synthesis and self-organization of gold colloids by simply incorporating gold salts into a solution prepared using polystyrene (PS)-polymethylmethacrylate copolymer and thiolated PS with propylene glycol methyl ether acetate as a solvent. The spin-coating and annealing of this solution then allows the formation of PS domains. Depending on the polymer concentration of the as-prepared solution, there can be either one or several gold nanoparticles (Au NPs) per PS domain. For high concentrations of Au NPs in PS domains, the coupling between plasmonic NPs leads to the observation of a second peak in the optical extinction spectrum. Such a collective effect could be relevant for the development of optical strain sensors in the near future. (papers)

  1. Single step synthesis and organization of gold colloids assisted by copolymer templates

    Science.gov (United States)

    Sarrazin, Aurélien; Gontier, Arthur; Plaud, Alexandre; Béal, Jérémie; Yockell-Lelièvre, Hélène; Bijeon, Jean-Louis; Plain, Jérôme; Adam, Pierre-Michel; Maurer, Thomas

    2014-06-01

    We report here an original single-step process for the synthesis and self-organization of gold colloids by simply incorporating gold salts into a solution prepared using polystyrene (PS)-polymethylmethacrylate copolymer and thiolated PS with propylene glycol methyl ether acetate as a solvent. The spin-coating and annealing of this solution then allows the formation of PS domains. Depending on the polymer concentration of the as-prepared solution, there can be either one or several gold nanoparticles (Au NPs) per PS domain. For high concentrations of Au NPs in PS domains, the coupling between plasmonic NPs leads to the observation of a second peak in the optical extinction spectrum. Such a collective effect could be relevant for the development of optical strain sensors in the near future.

  2. Improved synthesis and hydrogen storage of a microporous metal-organic framework material

    International Nuclear Information System (INIS)

    Cheng Shaojuan; Liu Shaobing; Zhao Qiang; Li Jinping

    2009-01-01

    A microporous metal-organic framework MOF-5 [Zn 4 O(BDC) 3 , BDC = 1,4-benzenedicarboxylic] was synthesized with and without H 2 O 2 by improved methods based on the previous studies. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy and nitrogen adsorption, and their hydrogen storage capacities were measured. The synthesis experiments showed that H 2 O 2 favored the growth of high quality sample, large pore volume and high specific surface area. The measurements of hydrogen storage indicated that the sample with higher specific surface area and large pore volume showed better hydrogen storage behavior than other samples. It was suggested that specific surface area and pore volume influenced the capacity of hydrogen storage for MOF-5 material.

  3. Synthesis and characterization of tunable coumarin- linked glasses as new class of organic/inorganic phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Luridiana, Alberto; Pretta, Gianluca; Secci, Francesco; Frongia, Angelo [Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Complesso universitario di Monserrato, SS 554, bivio per Sestu, Monserrato (Canada) (Italy); Chiriu, Daniele; Carbonaro, Carlo Maria; Corpino, Riccardo [Dipartimento di Fisica, Università degli Studi di Cagliari, Complesso universitario di Monserrato, SS 554, bivio per Sestu, Monserrato (Canada) (Italy); Ricci, Pier Carlo, E-mail: carlo.ricci@dsf.unica.it [Dipartimento di Fisica, Universitá degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, 09042 Monserrato (Canada) (Italy)

    2014-10-21

    It is well known that stilbene with a trans conformation is highly fluorescent. From the viewpoint of molecular structure, coumarins bear a carbon-carbon double bond which is fixed as trans conformation as in trans-stilbene through a lactone structure. This can help to avoid the trans-cis transformation of the double bond under ultraviolet (UV) irradiation as observed in stilbene compounds and results in strong fluorescence and high fluorescence quantum yield and photostability in most of coumarin derivatives. Herein we report some preliminary results about the synthesis and spectroscopic characterization of tunable coumarins and the development of a new linkage protocol for the obtainment of monolayer coumarin-covalently linked glasses. The resulting organic/inorganic coumarin/silica based Self-Assembled Monolayer (SMA) film is proposed as new phosphors for the substituting of critical raw materials, like rare earths, in photonics applications.

  4. Synthesis, functionalization, and applications of metal-organic frameworks in biomedicine.

    Science.gov (United States)

    Chen, Wei; Wu, Chunsheng

    2018-02-13

    Metal-organic frameworks (MOFs), also known as coordination polymers, have attracted extensive research interest in the past few decades due to their unique physical structures and potentially vast applications. In this review, we outline the recent progress in the synthesis, functionalization and applications of MOFs in biomedicine, mainly focusing on two promising, yet challenging areas, i.e., drug delivery and biosensing applications. A major challenge is the proper functionalization of MOFs with demanding properties suitable for biomedical applications. Extensive studies on MOFs in biomedicine have led to substantial progress in the control of key properties of MOFs such as toxicity, size and shape, and biological stability. Due to their flexible composition, pore size and easy functionalization properties, MOFs can be utilized as key components for the development of various functional systems, and their applications in drug delivery and biosensing are reviewed. Future trends and perspectives in these research areas are also outlined.

  5. Synthesis and physical properties of asymmetrical quaterthiophene derivatives as organic thin-film transistor materials

    Energy Technology Data Exchange (ETDEWEB)

    Shaik, Baji; Noh, Young Ri; Choi, Ho June; Yoon, Soon Byung; Lee, Sang Gyeong [Research Institute of Natura l Science, Gyeongsang National University, Jinju (Korea, Republic of); Yun, Myoung Hee; Kim, Jin Young [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2015-04-15

    We report here, synthesis, physical, thermal, and optoelectronic properties of compounds containing anthracene, anthraquinone, and 11,11,12,12-tetracyano-9,10-anthraquinodimethane units connected to quaterthiophene units. Three compounds, TQAO (6), TQAN (7), and TQAM (8) are synthesized by using Stille coupling, reduction, and Knoevenagel condensation reactions. These compounds were thermally stable and exhibited organic thin-film transistor (OTFT) properties. Among them, TQAM (8)-based OTFT has shown ambipolar mobility, both hole and electron mobility of 2.0 × 10{sup −6} and 2.43 × 10{sup −7} cm{sup 2}/Vs, respectively. TQAO (6) and TQAN (7) has shown low electron mobility of 5.58 × 10{sup −6} and 1.22 × 10{sup −5} cm{sup 2}/Vs, respectively.

  6. Sonochemical Synthesis of Photoluminescent Nanoscale Eu(III-Containing Metal-Organic Frameworks

    Directory of Open Access Journals (Sweden)

    Cheng-an TAO

    2015-11-01

    Full Text Available Nanoscale lanthanide-containing metal-organic frameworks (MOFs have more and more interest due to their great properties and potential applications, but how to construct them easily is still challenging. Here, we present a facile and rapid synthesis of Eu(III-containing Nanoscale MOF (denoted as NMOF under ultrasonic irradiation. The effect of the ratio and the addition order of metal ions and linkers on the morphology and size of MOFs was investigated. It is found that both of the ratio and the addition order can affect the morphology and size of 1.4-benzenedicarboxylic acid(H2BDC -based MOFs, but they show no evident influence on that of H2aBDC-based MOFs. The former exhibit typical emission bands of Eu(III ions, while the latter only show the photoluminescent properties of ligands.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9695

  7. Materials for n-type organic electronics: synthesis and properties of fluoroarene-thiophene semiconductors

    Science.gov (United States)

    Facchetti, Antonio; Yoon, Myung-Han; Katz, Howard E.; Marks, Tobin J.

    2003-11-01

    Recent progress in the field of organic electronics is due to a fruitful combination of both innovative molecular design and promising low-cost material/device assembly. Targeting the first strategy, we present here the general synthesis of fluoroarene-containing thiophene-based semiconductors and the study of their properties with respect to the corresponding fluorine-free hole-transporting analogues. The new compounds have been characterized by elemental analysis, mass spectrometry, and 1H- and 19F NMR. The dramatic influence of fluorine substitution and molecular architecture has been investigated by solution/film optical absorption, fluorescence emission, and cyclic voltammetry. Single crystal data for all of the oligomers have been obtained and will be presented. Film microstructure and morphology of this new class of materials have been studied by XRD and SEM. Particular emphasis will be posed on the solution-processable oligomers and polymers.

  8. Toward Developing Made-to-Order Metal-Organic Frameworks: Design, Synthesis and Applications

    KAUST Repository

    Ashri, Lubna Y.

    2016-05-26

    Synthesis of materials with certain properties for targeted applications is an ongoing challenge in materials science. One of the most interesting classes of solid-state materials that have been recently introduced with the potential to address this is metal-organic frameworks (MOFs). MOFs chemistry offers a higher degree of control over materials to be synthesized utilizing various new design strategies, such as the molecular building blocks (MBBs) and the supermolecular building layers (SBLs) approaches. Depending on using predetermined building blocks, these strategies permit the synthesis of MOFs with targeted topologies and enable fine tuning of their properties. This study examines a number of aspects of the design and synthesis of MOFs while exploring their possible utilization in two diverse fields related to energy and pharmaceutical applications. Concerning MOFs design and synthesis, the work presented here explores the rational design of various MOFs with predicted topologies and tunable cavities constructed by pillaring pre-targeted 2-periodic SBLs using the ligand-to-axial and six-connected axial-to-axial pillaring strategies. The effect of expanding the confined spaces in prepared MOFs or modifying their functionalities, while preserving the underlying network topology, was investigated. Additionally, The MBBs approach was employed to discover new modular polynuclear rare earth (RE)-MBBs in the presence of different angular polytopic ligands containing carboxylate and nitrogen moieties with the aid of a modulator. The goal was to assess the diverse possible coordination modes and construct highly-connected nets for utility in the design of new MOFs and enhance the predictability of structural outcomes. The effect of adjusting ligands’ length-to-width ratio on the prepared MOFs was also evaluated. As a result, the reaction conditions amenable for reliable formation of the unprecedented octadecanuclear, octanuclear and double tetranuclear RE-MBBs were

  9. Shape selectivity in organic synthesis; Selectividad de forma en sintesis organica

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Luenga, M.A.; Yates, M. [Instituto de Quimica-Fisica Rocasolano CSIC, Madrid (Spain)

    1995-12-31

    Heterogeneous catalysis is the most convenient method for many organic syntheses due mainly to the ease of experimental handling and the savings in costs, since finely divided catalysts suspended in the reaction medium (liquid in a high percentage of cases, due to the need for working at low temperatures to avoid undesired side reactions) can be easily recovered at the end of the reaction. Zeotypes are amongst the most important solid catalysts to be used in organic synthesis (1-5), due to their porous nature with controllable properties such as acidity,and molecular sized cavities where reactions take place in quasi-enzymatic conditions, since molecules of greater size than the pore opening are not able to enter react. This steric hindrance gives rise to the property defined as shape selectivity (2). Between the 1960`s and 1980`s catalysis with zeotypes was dedicated to petrochemical processes (refining and hydrotreating), due to the petroleum crises during that period. More recently their uses have been broadened to incorporate all types of organic syntheses, with appreciable advantages over more conventional catalysts in a number of processes. (Author)

  10. Synthesis of N,N-Bis(nonaflyl) Squaric Acid Diamide and its Application to Organic Reactions

    International Nuclear Information System (INIS)

    Cheon, Cheol Hong; Yamamoto, Hisashi

    2010-01-01

    We have developed a new strong Brφnsted acid bearing two nonaflyl groups based on the squaric acid scaffold. The Brφnsted acid 2 showed the almost same reactivity as bistriflyl squaramide 1 in Mukaiyama aldol and Michael reactions of benzaldehyde with silyl enol ether. Moreover, the utility of Brφnsted acid 2 could be expanded to carbonyl ene reaction of rac-citronellal. Further application of this new Brφnsted acid to organic reactions and to flow system reactors is currently underway in our laboratory. Brφnsted acid catalysis is one of the growing fields in modern organic synthesis.1 Although several Brφnsted acids, such as urea/thiourea, TADDOL, and phosphoric acid, have been applied to a variety of organic reactions, other Brφnsted acid scaffolds have been much less explored. Recently, Rawal et al have developed a Brφnsted acid catalyst based on squaric acid moiety and successfully applied it as a catalyst for conjugate addition of 1,3-dicarbonyl compounds to nitroolefins. More recently, we have developed a strong Brφnsted acid derived from squaric acid by introducing a strong electron withdrawing trifluoromethanesulfonyl (Tf) group and applied it to Mukaiyama aldol and Michael reaction of a variety of aldehydes, ketones, and α,β-unsaturated ketones. As a continuing effort to develop strong Brφnsted acids based on the squaric acid scaffold, it was expected that replacement of Tf group with a longer perfluoro-alkanesulfonyl group would be able to tune the physical properties, such as solubilities in organic solvents and fluoro-philicity, without loss of reactivity. Herein, we report the development of a new Brφnsted acid based on the squaric acid scaffold carrying two nonafluorobutanesulfonyl (Nf) groups and the preliminary results of its reactivity to various organic reactions

  11. Synthesis of a Parkinson's Disease Treatment Drug, the "R,R"-Tartrate Salt "of R"-Rasagiline: A Three Week Introductory Organic Chemistry Lab Sequence

    Science.gov (United States)

    Aguilar, Noberto; Garcia, Billy; Cunningham, Mark; David, Samuel

    2016-01-01

    A synthesis of the "R,R"-tartrate salt of the popular anti-Parkinson's drug "R"-rasagiline (Azilect) was adapted to introduce the organic laboratory student to a medically relevant synthesis. It makes use of concepts found in the undergraduate organic chemistry curriculum, appropriately fits into three approximately 4 h lab…

  12. Graphic organizers and their effects on the reading comprehension of students with LD: a synthesis of research.

    Science.gov (United States)

    Kim, Ae-Hwa; Vaughn, Sharon; Wanzek, Jeanne; Wei, Shangjin

    2004-01-01

    Previous research studies examining the effects of graphic organizers on reading comprehension for students with learning disabilities (LD) are reviewed. An extensive search of the professional literature between 1963 and June 2001 yielded a total of 21 group design intervention studies that met the criteria for inclusion in the synthesis. Using graphic organizers (i.e., semantic organizers, framed outlines, cognitive maps with and without a mnemonic) was associated with improved reading comprehension overall for students with LD. Compared to standardized reading measures, researcher-developed comprehension measures were associated with higher effect sizes. Initial gains demonstrated when using graphic organizers were not revealed during later comprehension tasks or on new comprehension tasks.

  13. Microwave-Enhanced Organic Syntheses for the Undergraduate Laboratory: Diels-Alder Cycloaddition, Wittig Reaction, and Williamson Ether Synthesis

    Science.gov (United States)

    Baar, Marsha R.; Falcone, Danielle; Gordon, Christopher

    2010-01-01

    Microwave heating enhanced the rate of three reactions typically performed in our undergraduate organic chemistry laboratory: a Diels-Alder cycloaddition, a Wittig salt formation, and a Williamson ether synthesis. Ninety-minute refluxes were shortened to 10 min using a laboratory-grade microwave oven. In addition, yields improved for the Wittig…

  14. The Cyclohexanol Cycle and Synthesis of Nylon 6,6: Green Chemistry in the Undergraduate Organic Laboratory

    Science.gov (United States)

    Dintzner, Matthew R.; Kinzie, Charles R.; Pulkrabek, Kimberly; Arena, Anthony F.

    2012-01-01

    A one-term synthesis project that incorporates many of the principles of green chemistry is presented for the undergraduate organic laboratory. In this multistep scheme of reactions, students react, recycle, and ultimately convert cyclohexanol to nylon 6,6. The individual reactions in the project employ environmentally friendly methodologies, and…

  15. Cerium-based metal organic frameworks with UiO-66 architecture: synthesis, properties and redox catalytic activity.

    Science.gov (United States)

    Lammert, Martin; Wharmby, Michael T; Smolders, Simon; Bueken, Bart; Lieb, Alexandra; Lomachenko, Kirill A; Vos, Dirk De; Stock, Norbert

    2015-08-14

    A series of nine Ce(iv)-based metal organic frameworks with the UiO-66 structure containing linker molecules of different sizes and functionalities were obtained under mild synthesis conditions and short reaction times. Thermal and chemical stabilities were determined and a Ce-UiO-66-BDC/TEMPO system was successfully employed for the aerobic oxidation of benzyl alcohol.

  16. Facile room-temperature solution-phase synthesis of a spherical covalent organic framework for high-resolution chromatographic separation.

    Science.gov (United States)

    Yang, Cheng-Xiong; Liu, Chang; Cao, Yi-Meng; Yan, Xiu-Ping

    2015-08-07

    A simple and facile room-temperature solution-phase synthesis was developed to fabricate a spherical covalent organic framework with large surface area, good solvent stability and high thermostability for high-resolution chromatographic separation of diverse important industrial analytes including alkanes, cyclohexane and benzene, α-pinene and β-pinene, and alcohols with high column efficiency and good precision.

  17. Synthesis of Sub-10 nm Two-Dimensional Covalent Organic Thin Film with Sharp Molecular Sieving Nanofiltration

    KAUST Repository

    Gadwal, Ikhlas; Sheng, Guan; Thankamony, Roshni Lilly; Liu, Yang; Li, Huifang; Lai, Zhiping

    2018-01-01

    We demonstrated here a novel and facile synthesis of two-dimensional (2D) covalent organic thin film with pore size around 1.5 nm using a planar, amphiphilic and substituted heptacyclic truxene based triamine and a simple dialdehyde as building

  18. The shock synthesis of complex organics from impacts into cometary analogue mixtures

    Science.gov (United States)

    Price, M.; Wozniakiewicz, P.; Cole, M.; Martins, Z.; Burchell, M.

    2014-07-01

    Introduction: If amino acids are required for the evolution of life, what was their source? Many different theories abound as to the source of amino acids on the early Earth including exogenous delivery from comets/asteroids (for example, glycine was found recently on comet Wild-2 [1]), formation in the protoplanetary nebula [2], or UV catalysed reactions of gases [3]. An alternative explanation is that amino acids can be shock-synthesised during the impact on an icy body onto a rocky body (or, equivalently, the impact of rocky body onto an icy surface). This theory is supported by computer simulations [4] and by very recent experimental data, which demonstrated the formation of simple (including abiotic) amino acids from shocks into ice mixtures mimicking the composition of comets and the surfaces of the icy Jovian and Saturnian satellites. Although the results from these experiments are fundamentally important, the yield of synthesised amino acids was low (nano-grams of material), complicating their detection and identification. In order to increase the collected yield of complex organics, and aid in their detection and identification, we have implemented a new collection technique within our hypervelocity impact facility. Experimental Methodology: Figure 1A) shows a low-resolution high-speed photograph of an impact plasma generated from an impact of a stainless-steel sphere into a mixture of water, CO_{2}, ammonia, and methanol ices. The plasma has an intense blue colour, and lasted for < 1 msec (the frame-rate of the camera). It is during and within this flash that complex organics are most likely synthesised, and thus to maximise the collection of these materials, we have implemented a new collection mechanism. Figure 1B) shows the prototype collection mechanism. Here an aluminium cold-plate (˜150 K) is placed in front of the target holder containing the ice mixtures. The plate has a central hole which allows the projectile to pass through to impact the ice

  19. Assessment of derelict soil quality: Abiotic, biotic and functional approaches.

    Science.gov (United States)

    Vincent, Quentin; Auclerc, Apolline; Beguiristain, Thierry; Leyval, Corinne

    2018-02-01

    The intensification and subsequent closing down of industrial activities during the last century has left behind large surfaces of derelict lands. Derelict soils have low fertility, can be contaminated, and many of them remain unused. However, with the increasing demand of soil surfaces, they might be considered as a resource, for example for non-food biomass production. The study of their physico-chemical properties and of their biodiversity and biological activity may provide indications for their potential re-use. The objective of our study was to investigate the quality of six derelict soils, considering abiotic, biotic, and functional parameters. We studied (i) the soil bacteria, fungi, meso- and macro-fauna and plant communities of six different derelict soils (two from coking plants, one from a settling pond, two constructed ones made from different substrates and remediated soil, and an inert waste storage one), and (ii) their decomposition function based on the decomposer trophic network, enzyme activities, mineralization activity, and organic pollutant degradation. Biodiversity levels in these soils were high, but all biotic parameters, except the mycorrhizal colonization level, discriminated them. Multivariate analysis showed that biotic parameters co-varied more with fertility proxies than with soil contamination parameters. Similarly, functional parameters significantly co-varied with abiotic parameters. Among functional parameters, macro-decomposer proportion, enzyme activity, average mineralization capacity, and microbial polycyclic aromatic hydrocarbon degraders were useful to discriminate the soils. We assessed their quality by combining abiotic, biotic, and functional parameters: the compost-amended constructed soil displayed the highest quality, while the settling pond soil and the contaminated constructed soil displayed the lowest. Although differences among the soils were highlighted, this study shows that derelict soils may provide a

  20. Resilience of cereal crops to abiotic stress: A review | Ahmad ...

    African Journals Online (AJOL)

    In the last century, conventional selection and breeding program proved to be highly effective in improving crops against abiotic stresses. Therefore, breeding for abiotic stress tolerance in crop plants should be given high research priority as abiotic stresses are the main factor negatively affecting crop growth and ...

  1. Safety aspects of genetically modified crops with abiotic stress tolerance

    NARCIS (Netherlands)

    Liang, C.; Prins, T.W.; Wiel, van de C.C.M.; Kok, E.J.

    2014-01-01

    Abiotic stress, such as drought, salinity, and temperature extremes, significantly reduce crop yields. Hence, development of abiotic stress-tolerant crops by modern biotechnology may contribute to global food security. Prior to introducing genetically modified crops with abiotic stress tolerance to

  2. Elucidating the Role of Carbon Sources on Abiotic and Biotic Release of Arsenic into Cambodian Aquifers

    Science.gov (United States)

    Koeneke, M.

    2017-12-01

    Arsenic (As) is a naturally occurring contaminant in Cambodia that has been contaminating well-water sources of millions of people. Commonly, studies look into the biotic factors that cause the arsenic to be released from aquifer sediments to groundwater. However, abiotic release of As from sediments, though little studied, may also play key roles in As contamination of well water. The goal of this research is to quantitatively compare organic-carbon mediated abiotic and biotic release of arsenic from sediments to groundwater. Batch anaerobic incubation experiments under abiotic (sodium azide used to immobilize microbes) and biotic conditions were conducted using Cambodian aquifer sediments, four different organic carbon sources (sodium lactate, sodium citrate, sodium oxalate, and humic acid), and six different carbon concentrations (0, 1, 2.5, 5, 10, 25mg C/L). Dissolved arsenic, iron(Fe), and manganese(Mn) concentrations in the treatments were measured 112 days . In addition, sediment and solution carbon solution was measured . Collectively, these show how different carbon sources, different carbon concentrations, and how abiotic and biotic factors impact the release of arsenic from Cambodian sediments into aquifers. Overall, an introduction of organic carbon to the soil increases the amount of As released from the sediment. The biotic + abiotic and abiotic conditions seemed to play a minimal role in the amount of As released. Dissolved species analysis showed us that 100% of the As was As(V), Our ICP-MS results vary due to the heterogeneity of samples, but when high levels are Fe are seen in solution, we also see high levels of As. We also see higher As concentrations when there is a smaller amount of Mn in solution.

  3. Enhanced Enzymatic Synthesis of a Cephalosporin, Cefadroclor, in the Presence of Organic Co-solvents.

    Science.gov (United States)

    Liu, Kun; Li, Sha; Pang, Xiao; Xu, Zheng; Li, Dengchao; Xu, Hong

    2017-05-01

    In this study, we investigated the enzymatic synthesis of a semi-synthetic cephalosporin, cefadroclor, from 7-aminodesacetoxymethyl-3-chlorocephalosporanic acid (7-ACCA) and p-OH-phenylglycine methyl ester (D-HPGM) using immobilized penicillin G acylase (IPA) in organic co-solvents. Ethylene glycol (EG) was employed as a component of the reaction mixture to improve the yield of cefadroclor. EG was found to increase the yield of cefadroclor by 15-45%. An investigation of altered reaction parameters including type and concentration of organic solvents, pH of reaction media, reaction temperature, molar ratio of substrates, enzyme loading, and IPA recycling was carried out in the buffer mixture. The best result was a 76.5% conversion of 7-ACCA, which was obtained from the reaction containing 20% EG (v/v), D-HPGM to 7-ACCA molar ratio of 4:1 and pH 6.2, catalyzed by 16 IU mL -1 IPA at 20 °C for 10 h. Under the optimum conditions, no significant loss of IPA activity was found after seven repeated reaction cycles. In addition, cefadroclor exhibited strong inhibitory activity against yeast, Bacillus subtilis NX-2, and Escherichia coli and weaker activity against Staphylococcus aureus and Pseudomonas aeruginosa. Cefadroclor is a potential antibiotic with activity against common pathogenic microorganisms.

  4. Synthesis and studies of novel high metal content organic aerogels obtained from a polymerizable titanium complex

    International Nuclear Information System (INIS)

    Cadra, S.

    2010-01-01

    Inertial Confinement Fusion (ICF) is a technique widely studied by the French atomic commission (CEA). Experiments will be performed within the Laser Megajoule (LMJ). They require innovative materials like organic aerogels that constitute laser targets. Such polymeric material must provide both a high porosity and a significant titanium percentage (1 atom %). Moreover, the monomers developed must be compatible with the synthesis procedure already in use. According to these specifications, a new polymerizable titanium complex was synthesized and fully characterized. This air and moisture-stable monomer provides a high metal percentage. Its free-radical cross-linked copolymerization affords several titanium-containing polymers. These gels were dried under supercritical conditions and organic aerogels were obtained. The chemical compositions of these materials were investigated by NMR, IR and elemental analysis while their structure was characterized by MEB-EDS, MET, N 2 adsorption/desorption isotherms measurements and SAXS. The data collected fit the specification requirements. Moreover, the mechanisms responsible of the foam nano-structure formation were discussed. (author) [fr

  5. Microwave Assisted Organic Synthesis of Heterocycles in Aqueous Media: Recent Advances in Medicinal Chemistry.

    Science.gov (United States)

    Frecentese, Francesco; Saccone, Irene; Caliendo, Giuseppe; Corvino, Angela; Fiorino, Ferdinando; Magli, Elisa; Perissutti, Elisa; Severino, Beatrice; Santagada, Vincenzo

    2016-01-01

    Green chemistry is a discipline of great interest in medicinal chemistry. It involves all fields of chemistry and it is based on the principle to conduct chemical reactions protecting the environment at the same time, through the use of chemical procedures able to avoid pollution. In this context, water as solvent is a good choice because it is abundant, nontoxic, non-caustic, and non-combustible. Even if microwave assisted organic reactions in conventional solvents have quickly progressed, in the recent years medicinal chemists have focused their attention to processes deemed not dangerous for the environment, using nanotechnology and greener solvents as water. Several reports of reaction optimizations and selectivities, demonstrating the capability of microwave to allow the obtaining of increased yields have been recently published using water as solvent. In this review, we selected the available knowledge related to microwave assisted organic synthesis in aqueous medium, furnishing examples of the newest strategies to obtain useful scaffolds and novel derivatives for medicinal chemistry purposes. The intention of this review is to demonstrate the exclusive ability of MAOS in water as solvent or as co-solvent. For this purpose we report here the most representative applications of MAOS using water as solvent, focusing on medicinal chemistry processes leading to interesting nitrogen containing heterocycles with potential pharmaceutical applications.

  6. Geometric Shape Regulation and Noncovalent Synthesis of One-Dimensional Organic Luminescent Nano-/Micro-Materials.

    Science.gov (United States)

    Song, Xiaoxian; Zhang, Zuolun; Zhang, Shoufeng; Wei, Jinbei; Ye, Kaiqi; Liu, Yu; Marder, Todd B; Wang, Yue

    2017-08-03

    Noncovalent synthesis of one-dimensional (1D) organic nano-/micro-materials with controllable geometric shapes or morphologies and special luminescent and electronic properties is one of the greatest challenges in modern chemistry and material science. Control of noncovalent interactions is fundamental for realizing desired 1D structures and crucial for understanding the functions of these interactions. Here, a series of thiophene-fused phenazines composed of a halogen-substituted π-conjugated plate and a pair of flexible side chains is presented, which displays halogen-dependent 1D self-assemblies. Luminescent 1D twisted wires, straight rods, and zigzag wires, respectively, can be generated in sequence when the halogen atoms are varied from the lightest F to the heaviest I. It was demonstrated that halogen-dependent anisotropic noncovalent interactions and mirror-symmetrical crystallization dominated the 1D-assembly behaviors of this class of molecules. The methodology developed in this study provides a potential strategy for constructing 1D organic materials with unique optoelectronic functions.

  7. A New Energy Source for Organic Synthesis in Europa's Surface Ice

    Science.gov (United States)

    Borucki, Jerome G.; Khare, Bishun; Cruikshank, Dale P.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    Colored regions on Jupiter's satellite Europa and other icy bodies in the outer Solar System may be contaminated by organic macromolecular solid material that is produced when surface ices are exposed to electrical energy. Hypervelocity meteorite impacts and fracture release tidal and tectonic stresses in icy crusts in the form of electrical discharges, which provide the energy for in situ synthesis of the organic solids. We report measurements of electrical discharge, light emission, and magnetic phenomena in hypervelocity impacts into ice with projectiles with V approx. 5 km/s. Part of the projectile's kinetic energy is converted into electrical potential, while the mechanical disruption of the impact also releases stress energy as light, heat, electrical, and magnetic fields as secondary emissions. These newly recognized energy sources suggest that the dark material in the area of impact craters are tholins generated from the energy of the impacts and that well up from the fracture zone. Large pools of liquid water would persist under the meteorite crater for thousands of years, with the potential for prebiotic chemistry to take place at an accelerated rate due to energy pumped in from the secondary emissions.

  8. Organic luminescent materials. First results on synthesis and characterization of Alq{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Baldacchini, G.; Gagliardi, S.; Montereali, R.M.; Pace, A. [ENEA, Centro Ricerche Frascati, Frascati, RM (Italy). Div. Fisica Applicata; Balaji Pode, R. [Nagpur University, Nagpur (India). Dept. of Physics

    2000-07-01

    Inorganic semiconductor diodes brought a technological revolution in the field of efficient light and laser sources in the last 20 years. New development in this field are expected from organic compounds, thanks to their low cost of synthesis and the relative easiness of growth as thin films. In particular, electrically pumped luminescent devices based on organic thin layers are among the most promising systems for next generation flat panel displays and semiconductor lasers. The tris - (8-hydroxy quinoline)-aluminium complex-Alq{sub 3} - is one of the most studied electro luminescent materials. In this paper, after a short introduction regarding historical development in the field, are reported preliminary results on the growth of Alq{sub 3} films and on their optical and spectroscopic characterization. [Italian] Negli ultimi 20 anni i diodi semiconduttori hanno portato una rivoluzione tecnologica nel campo delle sorgenti luminose e laser. Un nuovo sviluppo possibile in questo campo sono i composti organici, grazie al basso costo di sintesi e la relativa facilita' di crescerli in forma di film sottile. In particolare, dispositivi luminescenti pompati elettricamente basati su film sottili di materiali organici sono promettenti per una nuova generazione di display per schermi piatti e laser a Alq{sub 3} e' uno dei materiali elettroluminescenti piu' studiati. In questo rapporto, dopo una breve introduzione sullo sviluppo storico in questo campo, presentiamo i nostri primi risultati sulla crescita e caratterizzazione ottica di film di Alq{sub 3}.

  9. Improving abiotic stress tolerance of quinoa

    DEFF Research Database (Denmark)

    Yang, Aizheng

    Global food security faces the challenges of rapid population growth and shortage of water resources. Drought, heat waves and soil salinity are becoming more frequent and extreme due to climatic changes in many regions of the world, and resulting in yield reduction of many crops. It is hypothesized...... that quinoa has the potential to grow under a range of abiotic stresses, tolerating levels regarded as stresses in other crop species. Therefore cultivation of quinoa (Chenopodium quinoa Willd.) could be an alternative option in such regions. Even though quinoa is more tolerant to abiotic stress than most...... other crops, its productivity declines under severe drought, high salt conditions and harsh climate conditions. Different management approaches including water-saving irrigation methods (such as deficit irrigation, DI and alternate root-zone drying irrigation, ARD), inoculating crop seeds with plant...

  10. Synthesis of Thin Film Composite Metal-Organic Frameworks Membranes on Polymer Supports

    KAUST Repository

    Barankova, Eva

    2017-06-01

    Since the discovery of size-selective metal-organic frameworks (MOF) researchers have tried to manufacture them into gas separation membranes. ZIF-8 became the most studied MOF for membrane applications mainly because of its simple synthesis, good chemical and thermal stability, recent commercial availability and attractive pore size. The aim of this work is to develop convenient methods for growing ZIF thin layers on polymer supports to obtain defect-free ZIF membranes with good gas separation properties. We present new approaches for ZIF membranes preparation on polymers. We introduce zinc oxide nanoparticles in the support as a secondary metal source for ZIF-8 growth. Initially the ZnO particles were incorporated into the polymer matrix and later on the surface of the polymer by magnetron sputtering. In both cases, the ZnO facilitated to create more nucleation opportunities and improved the ZIF-8 growth compared to the synthesis without using ZnO. By employing the secondary seeded growth method, we were able to obtain thin (900 nm) ZIF-8 layer with good gas separation performance. Next, we propose a metal-chelating polymer as a suitable support for growing ZIF layers. Defect-free ZIF-8 films with a thickness of 600 nm could be obtained by a contra-diffusion method. ZIF-8 membranes were tested for permeation of hydrogen and hydrocarbons, and one of the highest selectivities reported so far for hydrogen/propane, and propylene/propane was obtained. Another promising method to facilitate the growth of MOFs on polymeric supports is the chemical functionalization of the support surface with functional groups, which can complex metal ions and which can covalently bond the MOF crystals. We functionalized the surface of a common porous polymeric membrane with amine groups, which took part in the reaction to form ZIF-8 nanocrystals. We observed an enhancement in adhesion between the ZIF layer and the support. The effect of parameters of the contra-diffusion experiment

  11. Abiotic factors influencing tropical dry forests regeneration

    Directory of Open Access Journals (Sweden)

    Ceccon Eliane

    2006-01-01

    Full Text Available Tropical dry forests represent nearly half the tropical forests in the world and are the ecosystems registering the greatest deterioration from the anthropogenic exploitation of the land. This paper presents a review on the dynamics of tropical dry forests regeneration and the main abiotic factors influencing this regeneration, such as seasonal nature, soil fertility and humidity, and natural and anthropic disturbances. The main purpose is to clearly understand an important part of TDF succession dynamics.

  12. Cortex proliferation in the root is a protective mechanism against abiotic stress.

    Science.gov (United States)

    Cui, Hongchang

    2015-01-01

    Although as an organ the root plays a pivotal role in nutrient and water uptake as well anchorage, individual cell types function distinctly. Cortex is regarded as the least differentiated cell type in the root, but little is known about its role in plant growth and physiology. In recent studies, we found that cortex proliferation can be induced by oxidative stress. Since all types of abiotic stress lead to oxidative stress, this finding suggests a role for cortex in coping with abiotic stress. This hypothesis was tested in this study using the spy mutant, which has an extra layer of cortex in the root. Interestingly, the spy mutant was shown to be hypersensitive to salt and oxidizing reagent applied to the leaves, but it was as tolerant as the wild type to these compounds in the soil. This result lends support to the notion that cortex has a protective role against abiotic stress arising from the soil.

  13. One-pot green synthesis of zinc oxide nano rice and its application as sonocatalyst for degradation of organic dye and synthesis of 2-benzimidazole derivatives

    Science.gov (United States)

    Paul, Bappi; Vadivel, Sethumathavan; Dhar, Siddhartha Sankar; Debbarma, Shyama; Kumaravel, M.

    2017-05-01

    In this paper, we report novel and green approach for one-pot biosynthesis of zinc oxide (ZnO) nanoparticles (NPs). Highly stable and hexagonal phase ZnO nanoparticles were synthesized using seeds extract from the tender pods of Parkia roxburghii and characterized by XRD, FT-IR, EDX, TEM, and N2 adsorption-desorption (BET) studies. The present method of synthesis of ZnO NPs is very efficient and cost effective. The powder XRD pattern furnished evidence for the formation of hexagonal close packing structure of ZnO NPs having average crystallite size 25.6 nm. The TEM image reveals rice shapes ZnO NPs are with an average diameter of 40-60 nm. The as-synthesized ZnO NPs has proved to be an excellent sonocatalysts for degradation of organic dye and synthesis of 2-benzimidazole derivatives.

  14. Anchoring of Cu(II) onto surface of porous metal-organic framework through post-synthesis modification for the synthesis of benzimidazoles and benzothiazoles

    Science.gov (United States)

    Kardanpour, Reihaneh; Tangestaninejad, Shahram; Mirkhani, Valiollah; Moghadam, Majid; Mohammadpoor-Baltork, Iraj; Zadehahmadi, Farnaz

    2016-03-01

    Efficient synthesis of various benzimidazoles and benzothiazoles under mild conditions catalyzed by Cu(II) anchored onto UiO-66-NH2 metal organic framework is reported. In this manner, first, the aminated UiO-66 was modified with thiophene-2-carbaldehyde and then the prepared Schiff base was reacted with CuCl2. The prepared catalyst was characterized by FT-IR, UV-vis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption, inductively coupled plasma atomic emission spectroscopy (ICP-AES) and field emission scanning electron microscopy (FE-SEM). The UiO-66-NH2-TC-Cu was applied as a highly efficient catalyst for synthesis of benzimidazole and benzothiazole derivatives by the reaction of aldehydes with 1,2-diaminobenzene or 2-aminothiophenol. The Cu(II)-containing MOF was reused several times without any appreciable loss of its efficiency.

  15. Abiotic Formation of Methyl Halides in the Terrestrial Environment

    Science.gov (United States)

    Keppler, F.

    2011-12-01

    Methyl chloride and methyl bromide are the most abundant chlorine and bromine containing organic compounds in the atmosphere. Since both compounds have relatively long tropospheric lifetimes they can effectively transport halogen atoms from the Earth's surface, where they are released, to the stratosphere and following photolytic oxidation form reactive halogen gases that lead to the chemical destruction of ozone. Methyl chloride and methyl bromide account for more than 20% of the ozone-depleting halogens delivered to the stratosphere and are predicted to grow in importance as the chlorine contribution to the stratosphere from anthropogenic CFCs decline. Today methyl chloride and methyl bromide originate mainly from natural sources with only a minor fraction considered to be of anthropogenic origin. However, until as recently as 2000 most of the methyl chloride and methyl bromide input to the atmosphere was considered to originate from the oceans, but investigations in recent years have clearly demonstrated that terrestrial sources such as biomass burning, wood-rotting fungi, coastal salt marshes, tropical vegetation and organic matter degradation must dominate the atmospheric budgets of these trace gases. However, many uncertainties still exist regarding strengths of both sources and sinks, as well as the mechanisms of formation of these naturally occurring halogenated gases. A better understanding of the atmospheric budget of both methyl chloride and methyl bromide is therefore required for reliable prediction of future ozone depletion. Biotic and abiotic methylation processes of chloride and bromide ion are considered to be the dominant pathways of formation of these methyl halides in nature. In this presentation I will focus on abiotic formation processes in the terrestrial environment and the potential parameters that control their emissions. Recent advances in our understanding of the abiotic formation pathway of methyl halides will be discussed. This will

  16. Study of the Performance of the Organic Extracts of Chenopodium ambrosioides for Ag Nanoparticle Synthesis

    Directory of Open Access Journals (Sweden)

    Luis M. Carrillo-López

    2016-01-01

    Full Text Available There are many ways to obtain metal nanoparticles: biological, physical, and chemical ways and combinations of these approaches. Synthesis assisted with plant extracts has been widely documented. However, one issue that is under discussion refers to the metabolites responsible for reduction and stabilization that confine nanoparticle growth and prevent coalescence between nanoparticles in order to avoid agglomeration/precipitation. In this study, Ag nanoparticles were synthesized using organic extracts of Chenopodium ambrosioides with different polarities (hexane, dichloromethane, and methanol. Each extract was phytochemically characterized to identify the nature of the metabolites responsible for nanoparticle formation. With methanol extract, the compounds responsible for reducing and stabilizing silver nanoparticle were associated with the presence of phenolic compounds (flavonoids and tannins, while, with dichloromethane and hexane extracts, the responsible compounds were mainly terpenoids. Large part of the reducing activity of secondary metabolites in C. ambrosioides is closely related to compounds with antioxidant capacity, such as phenolic compounds (flavone glycoside and isorhamnetin, which are the main constituents of the methanol extracts. Otherwise, terpenoids (trans-diol, α-terpineol, monoterpene hydroperoxides, and apiole are the central metabolites present in dichloromethane and hexane extracts.

  17. Development and functionalization of magnetic nanoparticles as powerful and green catalysts for organic synthesis

    Directory of Open Access Journals (Sweden)

    Ahmed M. Abu-Dief

    2018-03-01

    Full Text Available Magnetic nanoparticles are a highly worthy reactant for the correlation of homogeneous inorganic and organic containing catalysts. This review deals with the very recent main advances in the development of various nano catalytic systems by the immobilization of homogeneous catalysts onto magnetic nanoparticles. Catalytic fields include the use of mainly cobalt, nickel, copper, and zinc ferrites, as well as their mixed-metal combinations with Cr, Cd, Mn and sometimes some lanthanides. The ferrite nanomaterials are obtained mainly by co-precipitation and hydrothermal methods, sometimes by the sonochemical technique, micro emulsion and flame spray synthesis route. Catalytic processes with application of ferrite nanoparticles include degradation (in particular photocatalytic, reactions of dehydrogenation, oxidation, alkylation, C–C coupling, among other processes. Ferrite nano catalysts can be easily recovered from reaction systems and reused up to several runs almost without loss of catalytic activity. Finally, we draw conclusions and present a futurity outlook for the further development of new catalytic systems which are immobilized onto magnetic nanoparticles.

  18. Electrochemical synthesis of self-organized TiO2 crystalline nanotubes without annealing

    Science.gov (United States)

    Giorgi, Leonardo; Dikonimos, Theodoros; Giorgi, Rossella; Buonocore, Francesco; Faggio, Giuliana; Messina, Giacomo; Lisi, Nicola

    2018-03-01

    This work demonstrates that upon anodic polarization in an aqueous fluoride-containing electrolyte, TiO2 nanotube array films can be formed with a well-defined crystalline phase, rather than an amorphous one. The crystalline phase was obtained avoiding any high temperature annealing. We studied the formation of nanotubes in an HF/H2O medium and the development of crystalline grains on the nanotube wall, and we found a facile way to achieve crystalline TiO2 nanotube arrays through a one-step anodization. The crystallinity of the film was influenced by the synthesis parameters, and the optimization of the electrolyte composition and anodization conditions (applied voltage and time) were carried out. For comparison purposes, crystalline anatase TiO2 nanotubes were also prepared by thermal treatment of amorphous nanotubes grown in an organic bath (ethylene glycol/NH4F/H2O). The morphology and the crystallinity of the nanotubes were studied by field emission gun-scanning electron microscopy (FEG-SEM) and Raman spectroscopy, whereas the electrochemical and semiconducting properties were analyzed by means of linear sweep voltammetry, impedance spectroscopy, and Mott-Schottky plots. X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) allowed us to determine the surface composition and the electronic structure of the samples and to correlate them with the electrochemical data. The optimal conditions to achieve a crystalline phase with high donor concentration are defined.

  19. Engymatic synthesis of aspartame precursor in organic solvent; Yuki yobaichu deno asuparutemu zenkutai no koso gosei

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, K. [Okayama Univ., Okayama (Japan). Faculty of Engineering

    1996-11-05

    Taking up the synthetic reaction of the precursor of artificial sweetener aspartame for which thermolysin is used as the catalyst, the features and problems of enzymatic reaction in organic solvent are discussed. It is found that immobilized enzyme which has high activity and stability can be prepared by adsorbing high concentration thermolysin in Amberlite XAD7 followed by bridge immobilization. The initial rate of the synthesis and the stability of immobilized enzyme depend on the types of solvents. Continuous reaction is attempted using a columnar ferment reactor (PFR) in ethyl acetate at the beginning, but the yield decreases in a short period because the immobilized enzyme lose its activity gradually from the upper area of the column where Z-Asp concentration is high. When CSTR (complete mixed type reactor) is used, deactivation of immobilized enzyme can be restricted because low Z-Asp concentration in the reactor can be maintained. It is demonstrated that continuous reaction of longer than 200 hours is possible although the reaction rate is as low as 90%. 4 refs., 3 figs., 1 tab.

  20. A study on metal organic framework (MOF-177) synthesis, characterization and hydrogen adsorption -desorption cycles

    Energy Technology Data Exchange (ETDEWEB)

    Viditha, V.; Venkateswer Rao, M.; Srilatha, K.; Himabindu, V. [Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Kukatpally, Hyderabad-500 085, A.P. (India); Yerramilli, Anjaneyulu [Director, TLGVRC, JSU Box 18739, JSU, Jackson, MS 32917-0939 (United States)

    2013-07-01

    Hydrogen has long been considered to be an ideal alternative to fossil-fuel systems and much work has now been done on its storage. There are four main methods of hydrogen storage: as a liquid; as compressed hydrogen; in the form of metal hydrides; and by physisorption. Among all the materials metal organic frameworks (MOFs) are considered to have desirable properties like high porosity, pore volume and high thermal stability. MOF-177 is considered to be an ideal storage material. In this paper we study about its synthesis and hydrogen storage capacities of MOF-177 at different pressures ranging from 25, 50, 75 and 100 bar respectively. The obtained samples are characterized by XRD, BET and SEM. The recorded results show that the obtained hydrogen capacity is 1.1, 2.20, 2.4 and 2.80 wt%. The desorption capacity is 0.9, 2.1, 2.37 and 2.7 wt% at certain temperatures like 373 K.

  1. Synthesis, characterization and application of metal organic frameworks in the adsorption of dimethylamine

    International Nuclear Information System (INIS)

    Sun-Kou, Maria del Rosario; Bravo Hualpa, Fabiola; Beltran Suito, Rodrigo; Samanamu, Christian; Picasso Escobar, Gino

    2014-01-01

    This study investigated the removal of dimethylamine (DMA) by an adsorption mechanism using metal-organic frameworks (MOFs). The synthesis of the MOFs was performed by solvothermal methods. The characterization of the MOF obtained was made by attenuated total reflectance spectroscopy (ATR), proton nuclear magnetic resonance spectroscopy ("1H-NMR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The XRD diffractograms allowed to identify the structure of MOF as Dashkovaite, which has the molecular formula Mg(HCOO)_2.2H_2O; while the ATR studies revealed the presence of carbonyl group as most important functional group in the MOF structure. The morphological analysis showed that the MOF crystalline particles had a hexagonal shape, formed from filaments of around 7,5-8 microns in length. Adsorption experiments showed that the MOF had a high adsorption capacity of DMA (q_e= 307,96 mg.g"-"1). The kinetic data were fitted to the pseudo second order equation and the Elovich equation, while the adsorption isotherm was fitted to the Temkin equation and the Dubinin - Radushkevich equation, processes related to chemisorptions preferably on a heterogeneous surface. (author)

  2. Synthesis, characterization, and applications of electroactive polymeric nanostructures for organic coatings

    Science.gov (United States)

    Suryawanshi, Abhijit Jagnnath

    Electroactive polymers (EAP) such as polypyrrole (PPy) and polyaniline (PANI) are being explored intensively in the scientific community. Nanostructures of EAPs have low dimensions and high surface area enabling them to be considered for various useful applications. These applications are in several fields including corrosion inhibition, capacitors, artificial muscles, solar cells, polymer light emitting diodes, and energy storage devices. Nanostructures of EAPs have been synthesized in different morphologies such as nanowires, nanorods, nanotubes, nanospheres, and nanocapsules. This variety in morphology is traditionally achieved using soft templates, such as surfactant micelles, or hard templates, such as anodized aluminum oxide (AAO). Templates provide stability and groundwork from which the polymer can grow, but the templates add undesirable expense to the process and can change the properties of the nanoparticles by integrating its own properties. In this study a template free method is introduced to synthesize EAP nanostructures of PPy and PANI utilizing ozone oxidation. The simple techniques involve ozone exposure to the monomer solution to produce aqueous dispersions of EAP nanostructures. The synthesized nanostructures exhibit uniform morphology, low particle size distribution, and stability against agglomeration. Ozone oxidation is further explored for the synthesis of silver-PPy (Ag-PPy) core-shell nanospheres (CSNs). Coatings containing PPy nanospheres were formulated to study the corrosion inhibition efficiency of PPy nanospheres. Investigation of the coatings using electrochemical techniques revealed that the PPy nanospheres may provide corrosion inhibition against filiform corrosion by oxygen scavenging mechanism. Finally, organic corrosion inhibitors were incorporated in PPy to develop efficient corrosion inhibiting systems, by using the synergistic effects from PPy and organic corrosion inhibitors.

  3. Enzymatic synthesis of tasty oligopeptide in organic solvent. Yuki yobaichu deno teimisei origo pepuchido no koso gosei

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.; Tomita, K.; Nakanishi, K. (Okayama Univ., Okayama (Japan). Faculty of Engineering)

    1991-10-01

    An introduction is made to examples of the latest researches on methods to manufacture oligopeptides by enzymatic synthesizing methods in regards to to various processes using reactions in organic solvents as a means to increase the yield, particularly on synthesis of one that have taste effects. To raise the yield of peptides that are produced by condensing amino acid and amino acid derivatives, it is necessary that an equilibrium control reaction is operated in such a way that the product concentration and product moisture concentration are reduced, and the concentration of substrates of non-dissociation type is raised. In the case ofamino acid reacting with amino acid ester or amide, a velocity control is carried out, in which the velocity to produce the peptides from the acyl intermediates is raised and the velocity of the ester hydrolysis is slowed down. Examples of synthesis of tasty oligopeptides include, for example, the precursor in manufacturing artificial sweetener, aspartyl-phenylalanine methyl, as well as synthesis in an aqueous solution using special enzymes or in an organic solvent, and synthesis of other acidic amino acid oligomers. 24 refs., 2 figs.

  4. Nitrile-converting enzymes as a tool to improve biocatalysis in organic synthesis: recent insights and promises.

    Science.gov (United States)

    Gong, Jin-Song; Shi, Jin-Song; Lu, Zhen-Ming; Li, Heng; Zhou, Zhe-Min; Xu, Zheng-Hong

    2017-02-01

    Nitrile-converting enzymes, including nitrilase and nitrile hydratase (NHase), have received increasing attention from researchers of industrial biocatalysis because of their critical role as a tool in organic synthesis of carboxylic acids and amides from nitriles. To date, these bioconversion approaches are considered as one of the most potential industrial processes using resting cells or purified enzymes as catalysts for production of food additives, pharmaceutical, and agrochemical precursors. This review focuses on the distribution and catalytic mechanism research of nitrile-converting enzymes in recent years. Molecular biology aspects to improve the biocatalytic performance of microbial nitrilase and NHase are demonstrated. The process developments of microbial nitrilase and NHase for organic synthesis are also discussed.

  5. Synthesis and characterization of bimetallic metal-organic framework Cu-Ru-BTC with HKUST-1 structure.

    Science.gov (United States)

    Gotthardt, Meike A; Schoch, Roland; Wolf, Silke; Bauer, Matthias; Kleist, Wolfgang

    2015-02-07

    The bimetallic metal-organic framework Cu-Ru-BTC with the stoichiometric formula Cu2.75Ru0.25(BTC)2·xH2O, which is isoreticular to HKUST-1, was successfully prepared in a direct synthesis using mild reaction conditions. The partial substitution of Cu(2+) by Ru(3+) centers in the paddlewheel structure and the absence of other Ru-containing phases was proven using X-ray absorption spectroscopy.

  6. Green Synthesis of Organics and Nanomaterials and Sustainable Applications of Nano-Catalysts

    Science.gov (United States)

    The presentation summarizes our green chemical synthesis activity involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a variety o...

  7. Greener Synthesis of Organics and Nanomaterials: Sustainable Applications of Nano-Catalysts

    Science.gov (United States)

    The presentation summarizes our recent activity in chemical synthesis involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a varie...

  8. Green Synthesis of Organics and Nanomaterials and Sustainable Applications of Nano-Catalysts- HESTEC

    Science.gov (United States)

    The presentation summarizes our green chemical synthesis activity involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a variety o...

  9. Eco-friendly Synthesis of Organics and Nanomaterials: Sustainable Applications of Nano-Catalysts

    Science.gov (United States)

    The presentation summarizes our recent activity in chemical synthesis involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a varie...

  10. Microwave-Assisted Eco-Friendly Synthesis of Organics and Nanomaterials

    Science.gov (United States)

    This presentation summarizes our recent activity in MW-assisted synthesis, which involves benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The greener synthesis of heterocyclic compounds, coupling reac...

  11. A Safer and Convenient Synthesis of Sulfathiazole for Undergraduate Organic and Medicinal Chemistry Classes

    Science.gov (United States)

    Boyle, Jeff; Otty, Sandra; Sarojini, Vijayalekshmi

    2012-01-01

    A safer method for the synthesis of the sulfonamide drug sulfathiazole, for undergraduate classes, is described. This method improves upon procedures currently followed in several undergraduate teaching laboratories for the synthesis of sulfathiazole. Key features of this procedure include the total exclusion of pyridine, which has potential…

  12. Hydrothermal Synthesis and Characterization of a Metal-Organic Framework by Thermogravimetric Analysis, Powder X-Ray Diffraction, and Infrared Spectroscopy: An Integrative Inorganic Chemistry Experiment

    Science.gov (United States)

    Crane, Johanna L.; Anderson, Kelly E.; Conway, Samantha G.

    2015-01-01

    This advanced undergraduate laboratory experiment involves the synthesis and characterization of a metal-organic framework with microporous channels that are held intact via hydrogen bonding of the coordinated water molecules. The hydrothermal synthesis of Co[subscript 3](BTC)[subscript 2]·12H[subscript 2]O (BTC = 1,3,5-benzene tricarboxylic acid)…

  13. Organic titanates: a model for activating rapid room-temperature synthesis of shape-controlled CsPbBr3 nanocrystals and their derivatives.

    Science.gov (United States)

    Fang, Shaofan; Li, Guangshe; Li, Huixia; Lu, Yantong; Li, Liping

    2018-04-12

    The application of lead halide perovskite nanocrystals is challenged by the lack of strategies in rapid room-temperature synthesis with controlled morphologies. Here, we report on an initial study of adopting organic titanates as a model activator that promotes rapid room-temperature synthesis of shape-controlled, highly luminescent CsPbBr3 nanocrystals and their derivatives.

  14. Reactions of homolytic addition of polyhalogenoalkanes to unsafurated tin-organic compounds and their application in organic synthesis

    International Nuclear Information System (INIS)

    Rakhlin, V.I.; Mirskov, R.G.; Voronkov, M.G.

    1996-01-01

    Reactions of homolytic addition of polyhalogenoalkanes; including iodine compounds, to tin trialkylalkenyl derivatives are considered. They may be used as convenient method for synthesis of various polyhalogenoalkylsubstituted alicycles and heterocycles: cyclopropane, 1.3-dioxocycloalkanes, thiacycloalkanes, various nitrogen-containing heterocycles. 27 refs

  15. Synthesis of liquid crystals derived from nitroazobenzene: a proposed multistep synthesis applied to organic chemistry laboratory classes

    International Nuclear Information System (INIS)

    Cristiano, Rodrigo; Cabral, Marilia Gabriela B.; Aquino, Rafael B. de; Cristiano, Claudia M.Z.

    2014-01-01

    We describe a synthetic route consisting of five steps from aniline to obtain liquid crystal compounds derived from nitroazobenzene. Syntheses were performed during the second half of the semester in organic chemistry laboratory classes. Students characterized the liquid crystal phase by the standard melting point techniques, differential scanning calorimetry and polarized optical microscopy. These experiments allow undergraduate students to explore fundamentally important reactions in Organic Chemistry, as well as modern concepts in Chemistry such as self-assembly and self-organization, nanostructured materials and molecular electronics. (author)

  16. Correction: An unsymmetrical non-fullerene acceptor: synthesis via direct heteroarylation, self-assembly, and utility as a low energy absorber in organic photovoltaic cells.

    Science.gov (United States)

    Payne, Abby-Jo; Li, Shi; Dayneko, Sergey V; Risko, Chad; Welch, Gregory C

    2017-09-21

    Correction for 'An unsymmetrical non-fullerene acceptor: synthesis via direct heteroarylation, self-assembly, and utility as a low energy absorber in organic photovoltaic cells' by Abby-Jo Payne et al., Chem. Commun., 2017, 53, 10168-10171.

  17. Evaluation of Abiotic Resource LCIA Methods

    Directory of Open Access Journals (Sweden)

    Rodrigo A. F. Alvarenga

    2016-02-01

    Full Text Available In a life cycle assessment (LCA, the impacts on resources are evaluated at the area of protection (AoP with the same name, through life cycle impact assessment (LCIA methods. There are different LCIA methods available in literature that assesses abiotic resources, and the goal of this study was to propose recommendations for that impact category. We evaluated 19 different LCIA methods, through two criteria (scientific robustness and scope, divided into three assessment levels, i.e., resource accounting methods (RAM, midpoint, and endpoint. In order to support the assessment, we applied some LCIA methods to a case study of ethylene production. For RAM, the most suitable LCIA method was CEENE (Cumulative Exergy Extraction from the Natural Environment (but SED (Solar Energy Demand and ICEC (Industrial Cumulative Exergy Consumption/ECEC (Ecological Cumulative Exergy Consumption may also be recommended, while the midpoint level was ADP (Abiotic Depletion Potential, and the endpoint level was both the Recipe Endpoint and EPS2000 (Environmental Priority Strategies. We could notice that the assessment for the AoP Resources is not yet well established in the LCA community, since new LCIA methods (with different approaches and assessment frameworks are showing up, and this trend may continue in the future.

  18. Abscisic Acid and abiotic stress signaling.

    Science.gov (United States)

    Tuteja, Narendra

    2007-05-01

    Abiotic stress is severe environmental stress, which impairs crop production on irrigated land worldwide. Overall, the susceptibility or tolerance to the stress in plants is a coordinated action of multiple stress responsive genes, which also cross-talk with other components of stress signal transduction pathways. Plant responses to abiotic stress can be determined by the severity of the stress and by the metabolic status of the plant. Abscisic acid (ABA) is a phytohormone critical for plant growth and development and plays an important role in integrating various stress signals and controlling downstream stress responses. Plants have to adjust ABA levels constantly in responce to changing physiological and environmental conditions. To date, the mechanisms for fine-tuning of ABA levels remain elusive. The mechanisms by which plants respond to stress include both ABA-dependent and ABA-independent processes. Various transcription factors such as DREB2A/2B, AREB1, RD22BP1 and MYC/MYB are known to regulate the ABA-responsive gene expression through interacting with their corrosponding cis-acting elements such as DRE/CRT, ABRE and MYCRS/MYBRS, respectively. Understanding these mechanisms is important to improve stress tolerance in crops plants. This article first describes the general pathway for plant stress response followed by roles of ABA and transcription factors in stress tolerance including the regulation of ABA biosynthesis.

  19. Metal-Organic Frameworks: Building Block Design Strategies for the Synthesis of MOFs.

    KAUST Repository

    Luebke, Ryan

    2014-09-01

    A significant and ongoing challenge in materials chemistry and furthermore solid state chemistry is to design materials with the desired properties and characteristics. The field of Metal-Organic Frameworks (MOFs) offers several strategies to address this challenge and has proven fruitful at allowing some degree of control over the resultant materials synthesized. Several methodologies for synthesis of MOFs have been developed which rely on use of predetermined building blocks. The work presented herein is focused on the utilization of two of these design principles, namely the use of molecular building blocks (MBBs) and supermolecular building blocks (SBBs) to target MOF materials having desired connectivities (topologies). These design strategies also permit the introduction of specific chemical moieties, allowing for modification of the MOFs properties. This research is predominantly focused on two platforms (rht-MOFs and ftw-MOFs) which topologically speaking are edge transitive binodal nets; ftw being a (4,12)-connected net and rht being a (3,24)-connected net. These highly connected nets (at least one node having connectivity greater than eight) have been purposefully targeted to increase the predictability of structural outcome. A general trend in topology is that there is an inverse relationship between the connectivity of the node(s) and the number of topological outcomes. Therefore the key to this research (and to effective use of the SBB and MBB approaches) is identification of conditions which allow for reliable formation of the targeted MBBs and SBBs. In the case of the research presented herein: a 12-connected Group IV or Rare Earth based hexanuclear MBB and a 24-connected transition metal based SBB were successfully targeted and synthesized. These two synthetic platforms will be presented and used as examples of how these design methods have been (and can be further) utilized to modify existing materials or develop new materials for gas storage and

  20. Post-Synthesis Functionalization of Porous Organic Polymers for CO2 Capture

    KAUST Repository

    Al Otaibi, Mona S.

    2014-07-01

    Solid porous materials are network materials that contain space void. Porous Organic Polymers (POPs) are porous materials, which are constructed from organic building blocks and exhibit large surface area with low densities. Due to these characteristics, POPs have attracted attentions because of their potential use in application such as gas storage and chemical separation. This thesis presents a study of the synthesis of novel POP being a network based on 2,5- dibromobenzaldehyde and 1,3,5-triethynylbenzene linked together via Sonogashira- Hagihara (SH) coupling. This network showed a relatively good surface area of 770 m2/g and total pore volume of 0.59 cc/g. In addition, it proved to be chemically and thermally stable, maintaining the thermal stability up to 350oC. In addition to synthesize novel aldehyde-POP network, it was also possible to post synthetically modify a network via one-step post synthetic functionalization by amine. Ethelynediamine (EDA), Diethylenetriamine (DETA), and Tris(2-aminoethyl)amine (Tris-amine) are three different amines used for aldehyde-POP functionalization. The produced networks were aminated via different amine species substitution the aldehyde group present within the network. Modification to these networks resulted in a decrease in surface area from 770 m2.g-1 to 333 m2.g-1, 162 m2.g-1, and 211 m2.g-1 in respective to EDA, DETA, and Tris-amine. Although the surface areas were decreased, the CO2 adsorption was enhanced as evidenced by the increase of Qst (i.e., from 25 to 45 kJ.mol-1 for DETA at low coverage). Our findings are expected to strengthen existing research areas of the influence of different type of amines (e.g aromatic amine) on CO2 adsorption. Although amine grafting has been studied in other systems (e.g., PAFs and MOFs), we are the first to reported amine functionalized POPs using a novel one-step amine grafting PSM procedure. Future research might extend to study the interaction between CO2 and amine species under

  1. Synthesis of Amino Acid Precursors with Organic Solids in Planetesimals with Liquid Water

    Science.gov (United States)

    Kebukawa, Y.; Chan, Q. H. S.; Misawa, S.; Matsukuma, J.; Tachibana, S.; Kobayashi, K.; Zolensky, M. E.

    2017-07-01

    We demonstrated synthesis of a complex suite of amino acids simultaneously with IOM via hydrothermal experiments starting from formaldehyde, glycolaldehyde and ammonia, simulating the aqueous processing in the planetesimals.

  2. Synthesis of uniformly labelled organic compounds by polymerization of 14C ethylene

    International Nuclear Information System (INIS)

    Dauphin, J.-F.

    1972-01-01

    The synthesis of 14 C uniformly labelled compounds is described. By polymerization of 14 C ethylene, linear olefins with a double bond at α position were obtained. From these olefins, uniformly labelled alkanes, alcohols and acids were prepared [fr

  3. Electrochemical Synthesis of a Microporous Conductive Polymer Based on a Metal-Organic Framework Thin Film

    KAUST Repository

    Lu, Chunjing; Ben, Teng; Xu, Shixian; Qiu, Shilun

    2014-01-01

    A new approach to preparing 3D microporous conductive polymer has been demonstrated in the electrochemical synthesis of a porous polyaniline network with the utilization of a MOF thin film supported on a conducting substrate. The prepared porous

  4. Generation of RNA in abiotic conditions.

    Science.gov (United States)

    di Mauro, Ernesto

    Generation of RNA in abiotic conditions. Ernesto Di Mauro Dipartimento di Genetica Bi-ologia Molecolare, Universit` "Sapienza" Roma, Italy. a At least four conditions must be satisfied for the spontaneous generation of (pre)-genetic poly-mers: 1) availability of precursors that are activated enough to spontaneously polymerize. Preliminary studies showed that (a) nucleic bases and acyclonucleosides can be synthesized from formamide H2NCOH by simply heating with prebiotically available mineral catalysts [last reviewed in (1)], and that b) nucleic bases can be phosphorylated in every possible posi-tion [2'; 3'; 5'; cyclic 2',3'; cyclic 3',5' (2)]. The higher stability of the cyclic forms allows their accumulation. 2) A polymerization mechanism. A reaction showing the formation of RNA polymers starting from prebiotically plausible precursors (3',5' cyclic GMP and 3', 5'cyclic AMP) was recently reported (3). Polymerization in these conditions is thermodynamically up-hill and an equilibrium is attained that limits the maximum length of the polymer produced to about 40 nucleotides for polyG and 100 nucleotides for polyA. 3) Ligation of the synthesized oligomers. If this type of reaction could occur according to a terminal-joining mechanism and could generate canonical 3',5' phosphodiester bonds, exponential growth would be obtained of the generated oligomers. This type of reaction has been reported (4) , limited to homogeneous polyA sequences and leading to the production of polyA dimers and tetramers. What is still missing are: 4) mechanisms that provide the proof of principle for the generation of sequence complexity. We will show evidence for two mechanisms providing this proof of principle for simple complementary sequences. Namely: abiotic sequence complementary-driven terminal ligation and sequence-complementary terminal growth. In conclusion: all the steps leading to the generation of RNA in abiotic conditions are satisfied. (1) R Saladino, C Crestini, F

  5. Layer-by-Layer Method for the Synthesis and Growth of Surface Mounted Metal-Organic Frameworks (SURMOFs

    Directory of Open Access Journals (Sweden)

    Osama Shekhah

    2010-02-01

    Full Text Available A layer-by-layer method has been developed for the synthesis of metal-organic frameworks (MOFs and their deposition on functionalized organic surfaces. The approach is based on the sequential immersion of functionalized organic surfaces into solutions of the building blocks of the MOF, i.e., the organic ligand and the inorganic unit. The synthesis and growth of different types of MOFs on substrates with different functionalization, like COOH, OH and pyridine terminated surfaces, were studied and characterized with different surface characterization techniques. A controlled and highly oriented growth of very homogenous films was obtained using this method. The layer-by-layer method offered also the possibility to study the kinetics of film formation in more detail using surface plasmon resonance and quartz crystal microbalance. In addition, this method demonstrates the potential to synthesize new classes of MOFs not accessible by conventional methods. Finally, the controlled growth of MOF thin films is important for many applications like chemical sensors, membranes and related electrodes.

  6. Water/ionic liquid/organic three-phase interfacial synthesis of coral-like polypyrrole toward enhanced electrochemical capacitance

    International Nuclear Information System (INIS)

    Hou Linrui; Yuan Changzhou; Li Diankai; Yang Long; Shen Laifa; Zhang Fang; Zhang Xiaogang

    2011-01-01

    Highlights: → Interfacial synthesis strategies are proposed to synthesize PPy samples. → Water/ionic liquid /organic three-phase interface for preparing coral-like PPy. → Coral-like PPy with more ordered structure and better electronic conductivity. → Coral-like PPy owns higher rate performance and better electrochemical stability. - Abstract: Two interfacial synthesis strategies are proposed to synthesize polypyrrole samples for electrochemical capacitors (ECs). In contrast to water/organic two-phase route, unique water/ionic liquid (IL)/organic three-phase interface strategy is first performed to prepare coral-like polypyrrole with even better electrochemical capacitance, where 1-Ethyl-3-methylimidazolium tetrafluoroborate IL, as a 'buffering zone', is set between the water and organic phases to control the morphology and micro-structure of the polypyrrole phase during polymerization. The polypyrrole synthesized by three-phase interfacial route owns more ordered structure, less charge transfer resistance and better electronic conductivity, compared with two-phase method, and delivers larger specific capacitance, higher rate performance and better electrochemical stability at large current densities in 3 M KCl aqueous electrolyte.

  7. Bringing the science of proteins into the realm of organic chemistry: total chemical synthesis of SEP (synthetic erythropoiesis protein).

    Science.gov (United States)

    Kent, Stephen B H

    2013-11-11

    Erythropoietin, commonly known as EPO, is a glycoprotein hormone that stimulates the production of red blood cells. Recombinant EPO has been described as "arguably the most successful drug spawned by the revolution in recombinant DNA technology". Recently, the EPO glycoprotein molecule has re-emerged as a major target of synthetic organic chemistry. In this article I will give an account of an important body of earlier work on the chemical synthesis of a designed EPO analogue that had full biological activity and improved pharmacokinetic properties. The design and synthesis of this "synthetic erythropoiesis protein" was ahead of its time, but has gained new relevance in recent months. Here I will document the story of one of the major accomplishments of synthetic chemistry in a more complete way than is possible in the primary literature, and put the work in its contemporaneous context. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Two-dimensional parallel array technology as a new approach to automated combinatorial solid-phase organic synthesis

    Science.gov (United States)

    Brennan; Biddison; Frauendorf; Schwarcz; Keen; Ecker; Davis; Tinder; Swayze

    1998-01-01

    An automated, 96-well parallel array synthesizer for solid-phase organic synthesis has been designed and constructed. The instrument employs a unique reagent array delivery format, in which each reagent utilized has a dedicated plumbing system. An inert atmosphere is maintained during all phases of a synthesis, and temperature can be controlled via a thermal transfer plate which holds the injection molded reaction block. The reaction plate assembly slides in the X-axis direction, while eight nozzle blocks holding the reagent lines slide in the Y-axis direction, allowing for the extremely rapid delivery of any of 64 reagents to 96 wells. In addition, there are six banks of fixed nozzle blocks, which deliver the same reagent or solvent to eight wells at once, for a total of 72 possible reagents. The instrument is controlled by software which allows the straightforward programming of the synthesis of a larger number of compounds. This is accomplished by supplying a general synthetic procedure in the form of a command file, which calls upon certain reagents to be added to specific wells via lookup in a sequence file. The bottle position, flow rate, and concentration of each reagent is stored in a separate reagent table file. To demonstrate the utility of the parallel array synthesizer, a small combinatorial library of hydroxamic acids was prepared in high throughput mode for biological screening. Approximately 1300 compounds were prepared on a 10 μmole scale (3-5 mg) in a few weeks. The resulting crude compounds were generally >80% pure, and were utilized directly for high throughput screening in antibacterial assays. Several active wells were found, and the activity was verified by solution-phase synthesis of analytically pure material, indicating that the system described herein is an efficient means for the parallel synthesis of compounds for lead discovery. Copyright 1998 John Wiley & Sons, Inc.

  9. Alternative Splicing Control of Abiotic Stress Responses.

    Science.gov (United States)

    Laloum, Tom; Martín, Guiomar; Duque, Paula

    2018-02-01

    Alternative splicing, which generates multiple transcripts from the same gene, is an important modulator of gene expression that can increase proteome diversity and regulate mRNA levels. In plants, this post-transcriptional mechanism is markedly induced in response to environmental stress, and recent studies have identified alternative splicing events that allow rapid adjustment of the abundance and function of key stress-response components. In agreement, plant mutants defective in splicing factors are severely impaired in their response to abiotic stress. Notably, mounting evidence indicates that alternative splicing regulates stress responses largely by targeting the abscisic acid (ABA) pathway. We review here current understanding of post-transcriptional control of plant stress tolerance via alternative splicing and discuss research challenges for the near future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Additional insights into the adaptation of cotton plants under abiotic ...

    African Journals Online (AJOL)

    Abiotic stress is the primary cause of crop losses worldwide. In addition to protein coding genes, microRNAs (miRNAs) have emerged as important players in plant stress responses. Though miRNAs are key in regulating many aspects of plant developmental plasticity under abiotic stresses, very few information are available ...

  11. A significant abiotic pathway for the formation of unknown nitrogen in nature

    Science.gov (United States)

    Jokic, A.; Schulten, H.-R.; Cutler, J. N.; Schnitzer, M.; Huang, P. M.

    2004-03-01

    The global nitrogen cycle is of prime importance in natural ecosystems. However, the origin and nature of up to one-half of total soil N remains obscure despite all attempts at elucidation. Our data provide, for the first time, unequivocal evidence that the promoting action of Mn (IV) oxide on the Maillard reaction (sugar-amino acid condensation) under ambient conditions results in the abiotic formation of heterocyclic N compounds, which are often referred to as unknown nitrogen, and of amides which are apparently the dominant N moieties in nature. The information presented is of fundamental significance in understanding the role of mineral colloids in abiotic transformations of organic N moieties, the incorporation of N in the organic matrix of fossil fuels, and the global N cycle.

  12. Synthesis and Characterization of Metal-Organic Frameworks (MOFs) for Photon Collection and Energy Transfer

    Science.gov (United States)

    So, Monica C.

    Projected global energy demand is widely believed to reach 30 TW by 2050. Currently, fossil fuels collectively represent over 80% of our total energy supply, while only 10% come from renewable sources. To meet future demands, however, we must maximize our use of renewable resources while minimizing our dependence on fossil fuels. While there are many sources of renewable energy, solar energy is one of the most abundant; in fact, the sun delivers up to 67 TW of power annually, which exceeds the projected energy demand in 2050. While there are multiple ways to convert sunlight to electricity, organic photovoltaics (OPVs) has the shortest energy payback time; this is the time required for the PV module to generate the equivalent amount of energy that originally was used to manufacture the PV module. OPVs show promise for light-to-electrical energy conversion with the best performing cells having power conversion efficiencies of 8%, but the theoretical maximum is at 32%. If efficiencies can be increased to even a fraction of the way to ˜16%, OPVs would be more cost-competitive with their inorganic counterparts. However, there are four major challenges in improving OPV performance. These include (a) poor light harvesting, due to a limited range of absorbance of visible light, (b) inefficient exciton splitting into holes and electrons, due to the limited diffusion length of excitons (typically ca. 10 nm), (c) increased recombination of separated charges at the donor/acceptor interface, and (d) inefficient collection of charges at the active layer/electrode interface (i.e. partial electrical shorting). OPVs constructed from conventional materials and architectures involve conflicting design requirements; this makes it impossible to address all four problems simultaneously. The projects described in this dissertation involve the design, synthesis, and characterization of a new class of OPV materials that have the potential to overcome the problems with conventional cells

  13. Low Band Gap Polymers for Roll-to-Roll Coated Organic Photovoltaics – Design, Synthesis and Characterization

    DEFF Research Database (Denmark)

    Bundgaard, Eva; Hagemann, Ole; Jørgensen, Mikkel

    2011-01-01

    In this paper we present the design and synthesis of 25 new low band gap polymers. The polymers were characterized by UV-vis spectroscopy which showed optical band gaps of 2.0–0.9 eV. The polymers which were soluble enough were applied in organic photovoltaics, both small area devices with a spin...... coated active layer and in large area modules where all layers including the active layer were either roll-to-roll coated or printed. These experiments showed that the design of polymers compatible with roll-toroll coating is not straightforward and that there are various issues such as donor...

  14. Novel Easy Preparations of Some Aromatic Iodine(I, III, and V Reagents, Widely Applied in Modern Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Lech Skulski

    2003-01-01

    Full Text Available We report our novel (or considerably improved methods for the synthesis of aromatic iodides, (dichloroiodoarenes, (diacetoxyiodoarenes, [bis(trifluoroacetoxy-iodo]arenes, iodylarenes and diaryliodonium salts, as well as some facile, oxidative anion metatheses in crude diaryliodonium or tetraalkylammonium halides and, for comparison, potassium halides. All our formerly published papers were discussed and explained in our review “Organic Iodine(I, III, and V Chemistry: 10 Years of Development at the Medical University of Warsaw, Poland” (1990-2000 [1]. Our newest results are discussed below.

  15. Transforming growth factor-beta 1 stimulates synthesis of proteoglycan aggregates in calf articular cartilage organ cultures

    International Nuclear Information System (INIS)

    Morales, T.I.

    1991-01-01

    Previous work showed that transforming growth factor-beta 1 (TGF-beta 1), added alone to bovine cartilage organ cultures, stimulated [35S]sulfate incorporation into macromolecular material but did not investigate the fidelity of the stimulated system to maintain synthesis of cartilage-type proteoglycans. This paper provides evidence that chondrocytes synthesize the appropriate proteoglycan matrix under TGF-beta 1 stimulation: (1) there is a coordinated increase in hyaluronic acid and proteoglycan monomer synthesis, (2) link-stable proteoglycan aggregates are assembled, (3) the hybrid chondroitin sulfate/keratan sulfate monomeric species is synthesized, and (4) there is an increase in protein core synthesis. Some variation in glycosylation patterns was observed when proteoglycans synthesized under TGF-beta 1 stimulation were compared to those synthesized under basal conditions. Thus comparing TGF-beta 1 to basal samples respectively, the monomers were larger (Kav on Sepharose CL-2B = 0.29 vs 0.41), the chondroitin sulfate chains were longer by approximately 3.5 kDa, the percentage of total glycosaminoglycan in keratan sulfate increased slightly from approximately 4% (basal) to approximately 6%, and the unsulfated disaccharide decreased from 28% (basal) to 12%. All of these variations are in the direction of a more anionic proteoglycan. Since the ability of proteoglycans to confer resiliency to the cartilage matrix is directly related to their anionic nature, these changes would presumably have a beneficial effect on tissue function

  16. ROS-mediated abiotic stress-induced programmed cell death in plants

    Directory of Open Access Journals (Sweden)

    Veselin ePetrov

    2015-02-01

    Full Text Available During the course of their ontogenesis, plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms have developed complex strategies to withstand them. When the intensity of a detrimental factor is high, one of the defense programs employed by plants is the induction of programmed cell death (PCD. This is an active, genetically controlled process which is initiated to isolate and remove damaged tissues thereby ensuring the survival of the organism. The mechanism of PCD induction usually includes an increase in the levels of reactive oxygen species (ROS which are utilized as mediators of the stress signal. Abiotic stress-induced PCD is not only a process of fundamental biological importance, but also of considerable interest to agricultural practice as it has the potential to significantly influence crop yield. Therefore, numerous scientific enterprises have focused on elucidating the mechanisms leading to and controlling PCD in response to adverse conditions in plants. This knowledge may help to develop novel strategies to obtain more resilient crop varieties with improved tolerance and enhanced productivity. The aim of the present review is to summarize the recent advances in research on ROS-induced PCD related to abiotic stress and the role of the organelles in the process.

  17. Use of organic precursors and graphenes in the controlled synthesis of carbon-containing nanomaterials for energy storage and conversion.

    Science.gov (United States)

    Yang, Shubin; Bachman, Robert E; Feng, Xinliang; Müllen, Klaus

    2013-01-15

    The development of high-performance electrochemical energy storage and conversion devices, including supercapacitors, lithium-ion batteries, and fuel cells, is an important step on the road to alternative energy technologies. Carbon-containing nanomaterials (CCNMs), defined here as pure carbon materials and carbon/metal (oxide, hydroxide) hybrids with structural features on the nanometer scale, show potential application in such devices. Because of their pronounced electrochemical activity, high chemical and thermal stability and low cost, researchers are interested in CCNMs to serve as electrodes in energy-related devices. Various all-carbon materials are candidates for electrochemical energy storage and conversion devices. Furthermore, carbon-based hybrid materials, which consist of a carbon component with metal oxide- or metal hydroxide-based nanostructures, offer the opportunity to combine the attractive properties of these two components and tune the behavior of the resulting materials. As such, the design and synthesis of CCNMs provide an attractive route for the construction of high-performance electrode materials. Studies in these areas have revealed that both the composition and the fabrication protocol employed in preparing CCNMs influence the morphology and microstructure of the resulting material and its electrochemical performance. Consequently, researchers have developed several synthesis strategies, including hard-templated, soft-templated, and template-free synthesis of CCNMs. In this Account, we focus on recent advances in the controlled synthesis of such CCNMs and the potential of the resulting materials for energy storage or conversion applications. The Account is divided into four major categories based on the carbon precursor employed in the synthesis: low molecular weight organic or organometallic molecules, hyperbranched or cross-linked polymers consisting of aromatic subunits, self-assembling discotic molecules, and graphenes. In each case

  18. BASIC SYNTHESIS AND BIOLOGICAL ACTIVITY OF SOME PHOSPHORCONTATNING ORGANIC COMPOUNDS CONTAINING FRAGMENTS OF UREA AND TRYHLORETILAMID

    OpenAIRE

    Gushylyk B.

    2013-01-01

    Data about directions of synthesis and use of the phosphororganic compounds in technics, biology and medicine is presented in the paper. Antimicrobial activity of 51 phosphororganic salts and ilides containing urine and threechlor ethylenamide has been studied. Perspective of the development of effective antimicrobial substances has been determined

  19. BASIC SYNTHESIS AND BIOLOGICAL ACTIVITY OF SOME PHOSPHORCONTATNING ORGANIC COMPOUNDS CONTAINING FRAGMENTS OF UREA AND TRYHLORETILAMID

    Directory of Open Access Journals (Sweden)

    Gushylyk B.

    2013-10-01

    Full Text Available Data about directions of synthesis and use of the phosphororganic compounds in technics, biology and medicine is presented in the paper. Antimicrobial activity of 51 phosphororganic salts and ilides containing urine and threechlor ethylenamide has been studied. Perspective of the development of effective antimicrobial substances has been determined

  20. In situ synthesis of fluorescent magnetosomes using an organic membrane as a soft template.

    Science.gov (United States)

    Ke, Wenjing; Zhang, Juhua; An, Xueqin; Zhang, Bo

    2017-05-04

    A novel approach was presented for the in situ synthesis of fluorescent magnetosomes by biological mineralization and carbonization processes for the first time. The surface structures, magnetism and fluorescence were studied, and the cytotoxicity tests and fluorescent trace in liposomes were probed. The fluorescent magnetosomes exhibit not only unique fluorescence and ferromagnetic properties but also low toxicity and superior imaging capability.

  1. Assembly-Disassembly-Organization-Reassembly Synthesis of Zeolites Based on cfi-Type Layers

    Czech Academy of Sciences Publication Activity Database

    Firth, D. S.; Morris, S. A.; Wheatley, P. S.; Russell, S. E.; Slawin, A. M. Z.; Dawson, D. M.; Mayoral, A.; Opanasenko, Maksym; Položij, M.; Čejka, Jiří; Nachtigall, P.; Morris, R. E.

    2017-01-01

    Roč. 29, č. 13 (2017), s. 5605-5611 ISSN 0897-4756 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : large-pore zeolite * hydrothermal synthesis * preferential location Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 9.466, year: 2016

  2. Enzymatic synthesis of polyol seters in aqueous - organic two-phase systems

    NARCIS (Netherlands)

    Janssen, A.

    1993-01-01

    The last decade increasingly attention is paid to lipases as catalysts for synthesis of components, such as fatty acid-based surfactants, flavors, edible oil equivalents, monomers and polymers, and amides. In this thesis, the lipase-catalyzed esterification of polyols and fatty acids is

  3. Enzymatic synthesis of pyrene-labeled polyphosphoinositides and their behavior in organic solvents and phosphatidylcholine bilayers

    NARCIS (Netherlands)

    Gadella, Th.W.J.; Moritz, A.; Westerman, J.; Wirtz, K.W.A.

    1990-01-01

    A method is reported for the synthesis of pyrene-labeled analogues of phosphatidylinositol 4-phosphate (Pyr-PIP) and phosphatidylinositol 4,5-bisphosphate (Pyr-PIP,) from sn-2-(pyrenyl-decanoy1)phosphatidylinositol (Pyr-PI) using partially purified PI and PIP kinase preparations. Phos-phorylation of

  4. Student-Fabricated Microfluidic Devices as Flow Reactors for Organic and Inorganic Synthesis

    Science.gov (United States)

    Feng, Z. Vivian; Edelman, Kate R.; Swanson, Benjamin P.

    2015-01-01

    Flow synthesis in microfluidic devices has been rapidly adapted in the pharmaceutical industry and in many research laboratories. Yet, the cost of commercial flow reactors is a major factor limiting the dissemination of this technology in the undergraduate curriculum. Here, we present a laboratory activity where students design and fabricate…

  5. A Multistep Synthesis Featuring Classic Carbonyl Chemistry for the Advanced Organic Chemistry Laboratory

    Science.gov (United States)

    Duff, David B.; Abbe, Tyler G.; Goess, Brian C.

    2012-01-01

    A multistep synthesis of 5-isopropyl-1,3-cyclohexanedione is carried out from three commodity chemicals. The sequence involves an aldol condensation, Dieckmann-type annulation, ester hydrolysis, and decarboxylation. No purification is required until after the final step, at which point gravity column chromatography provides the desired product in…

  6. Modulated synthesis of chromium-based metal-organic framework (MIL-101) with enhanced hydrogen uptake

    CSIR Research Space (South Africa)

    Ren, Jianwei

    2014-08-01

    Full Text Available Modulated synthesis of MIL-101(Cr) in high yield and with good reproducibility using formic acid as a modulator is reported. Higher molar ratio of formic acid/CrCl(sub3) was found to form better shape-defined MIL-101(Cr) crystals with higher surface...

  7. A Green, Enantioselective Synthesis of Warfarin for the Undergraduate Organic Laboratory

    Science.gov (United States)

    Wong, Terence C.; Sultana, Camille M.; Vosburg, David A.

    2010-01-01

    The enantioselective synthesis of drugs is of fundamental importance in the pharmaceutical industry. In this experiment, students synthesize either enantiomer of warfarin, a widely used anticoagulant, in a single step from inexpensive starting materials. Stereoselectivity is induced by a commercial organocatalyst, ("R","R")- or…

  8. The synthesis and chemiluminescence of a stable 1,2-dioxetane : an organic chemistry laboratory experiment

    NARCIS (Netherlands)

    Meijer, E.W.; Wynberg, H.

    1982-01-01

    An expt. for the synthesis of adamantylideneadamantane-1,2-dioxetane illustrating the concepts of the singlet O reaction and chemiluminescence, is described. All intermediates and products can be identified by undergraduate students using routine spectroscopic anal. [on SciFinder (R)

  9. Soft templating strategies for the synthesis of mesoporous materials: inorganic, organic-inorganic hybrid and purely organic solids.

    Science.gov (United States)

    Pal, Nabanita; Bhaumik, Asim

    2013-03-01

    With the discovery of MCM-41 by Mobil researchers in 1992 the journey of the research on mesoporous materials started and in the 21st century this area of scientific investigation have extended into numerous branches, many of which contribute significantly in emerging areas like catalysis, energy, environment and biomedical research. As a consequence thousands of publications came out in large varieties of national and international journals. In this review, we have tried to summarize the published works on various synthetic pathways and formation mechanisms of different mesoporous materials viz. inorganic, organic-inorganic hybrid and purely organic solids via soft templating pathways. Generation of nanoscale porosity in a solid material usually requires participation of organic template (more specifically surfactants and their supramolecular assemblies) called structure-directing agent (SDA) in the bottom-up chemical reaction process. Different techniques employed for the syntheses of inorganic mesoporous solids, like silicas, metal doped silicas, transition and non-transition metal oxides, mixed oxides, metallophosphates, organic-inorganic hybrids as well as purely organic mesoporous materials like carbons, polymers etc. using surfactants are depicted schematically and elaborately in this paper. Moreover, some of the frontline applications of these mesoporous solids, which are directly related to their functionality, composition and surface properties are discussed at the appropriate places. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Lifetimes of organic photovoltaics: Design and synthesis of single oligomer molecules in order to study chemical degradation mechanisms

    DEFF Research Database (Denmark)

    Alstrup, J.; Norrman, K.; Jørgensen, M.

    2006-01-01

    Degradation mechanisms in organic and polymer photovoltaics are addressed through the study of an organic photovoltaic molecule based on a single phenylene-vinylene-type oligomer molecule. The synthesis of such a model compound with different end-groups is presented that allows for assignment...... of degradation products from different parts of the molecule. Photovoltaic devices with and without C(60) have been prepared and their characteristics under AM1.5 conditions are reported. The degradation of the active phenylene-vinylene compound in darkness and after 20h of illumination were investigated using...... a mass spectrometric technique (time-of-flight secondary ion mass spectrometry) allowing elucidation of the oxidative degradation pathways. (c) 2006 Elsevier B.V. All rights reserved....

  11. Particle size studies to reveal crystallization mechanisms of the metal organic framework HKUST-1 during sonochemical synthesis.

    Science.gov (United States)

    Armstrong, Mitchell R; Senthilnathan, Sethuraman; Balzer, Christopher J; Shan, Bohan; Chen, Liang; Mu, Bin

    2017-01-01

    Systematic studies of key operating parameters for the sonochemical synthesis of the metal organic framework (MOF) HKUST-1(also called CuBTC) were performed including reaction time, reactor volume, sonication amplitude, sonication tip size, solvent composition, and reactant concentrations analyzed through SEM particle size analysis. Trends in the particle size and size distributions show reproducible control of average particle sizes between 1 and 4μm. These results along with complementary studies in sonofragmentation and temperature control were conducted to compare these results to kinetic crystal growth models found in literature to develop a plausible hypothetical mechanism for ultrasound-assisted growth of metal-organic-frameworks composed of a competitive mechanism including constructive solid-on-solid (SOS) crystal growth and a deconstructive sonofragmentation. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Synthesis of Sub-10 nm Two-Dimensional Covalent Organic Thin Film with Sharp Molecular Sieving Nanofiltration

    KAUST Repository

    Gadwal, Ikhlas

    2018-04-06

    We demonstrated here a novel and facile synthesis of two-dimensional (2D) covalent organic thin film with pore size around 1.5 nm using a planar, amphiphilic and substituted heptacyclic truxene based triamine and a simple dialdehyde as building blocks by dynamic imine bond formation at the air/water interface using Langmuir–Blodgett (LB) method. Optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM), all unanimously showed the formation of large, molecularly thin and free-standing membrane that can be easily transferred on different substrate surfaces. The 2D membrane supported on a porous polysulfone showed a rejection rate of 64 and 71% for NaCl and MgSO4, respectively, and a clear molecular sieving at molecular size around 1.3 nm, which demonstrated a great potential in the application of pretreatment of seawater desalination and separation of organic molecules.

  13. Chemical Priming of Plants Against Multiple Abiotic Stresses: Mission Possible?

    KAUST Repository

    Savvides, Andreas

    2015-12-15

    Crop plants are subjected to multiple abiotic stresses during their lifespan that greatly reduce productivity and threaten global food security. Recent research suggests that plants can be primed by chemical compounds to better tolerate different abiotic stresses. Chemical priming is a promising field in plant stress physiology and crop stress management. We review here promising chemical agents such as sodium nitroprusside, hydrogen peroxide, sodium hydrosulfide, melatonin, and polyamines that can potentially confer enhanced tolerance when plants are exposed to multiple abiotic stresses. The challenges and opportunities of chemical priming are addressed, with the aim to boost future research towards effective application in crop stress management.

  14. Chemical Priming of Plants Against Multiple Abiotic Stresses: Mission Possible?

    KAUST Repository

    Savvides, Andreas; Ali, Shawkat; Tester, Mark A.; Fotopoulos, Vasileios

    2015-01-01

    Crop plants are subjected to multiple abiotic stresses during their lifespan that greatly reduce productivity and threaten global food security. Recent research suggests that plants can be primed by chemical compounds to better tolerate different abiotic stresses. Chemical priming is a promising field in plant stress physiology and crop stress management. We review here promising chemical agents such as sodium nitroprusside, hydrogen peroxide, sodium hydrosulfide, melatonin, and polyamines that can potentially confer enhanced tolerance when plants are exposed to multiple abiotic stresses. The challenges and opportunities of chemical priming are addressed, with the aim to boost future research towards effective application in crop stress management.

  15. Recent Molecular Advances on Downstream Plant Responses to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Cláudia Regina Batista de Souza

    2012-07-01

    Full Text Available Abiotic stresses such as extremes of temperature and pH, high salinity and drought, comprise some of the major factors causing extensive losses to crop production worldwide. Understanding how plants respond and adapt at cellular and molecular levels to continuous environmental changes is a pre-requisite for the generation of resistant or tolerant plants to abiotic stresses. In this review we aimed to present the recent advances on mechanisms of downstream plant responses to abiotic stresses and the use of stress-related genes in the development of genetically engineered crops.

  16. Design, Synthesis and Characterization of Functional Metal-Organic Framework Materials

    KAUST Repository

    Alamer, Badriah

    2015-01-01

    are known as Metal Organic Framework (MOFs). This exceptional new family of porous materials is fabricated by linkage of metal ions or clusters and organic linkers via strong bonds. MOFs have been awarded with remarkable interest and widely studied due

  17. An Introduction to Zeolite Synthesis Using Imidazolium-Based Cations as Organic Structure-Directing Agents.

    Science.gov (United States)

    Vinaches, Paloma; Bernardo-Gusmão, Katia; Pergher, Sibele B C

    2017-08-06

    Zeolite synthesis is a wide area of study with increasing popularity. Several general reviews have already been published, but they did not summarize the study of imidazolium species in zeolite synthesis. Imidazolium derivatives are promising compounds in the search for new zeolites and can be used to help understand the structure-directing role. Nearly 50 different imidazolium cations have already been used, resulting in a variety of zeolitic types, but there are still many derivatives to be studied. In this context, the purpose of this short review is to help researchers starting in this area by summarizing the most important concepts related to imidazolium-based zeolite studies and by presenting a table of recent imidazolium derivatives that have been recently studied to facilitate filling in the knowledge gaps.

  18. Synthesis of organic substances labelled with 14C and 35S

    International Nuclear Information System (INIS)

    Pichat, L.

    1958-01-01

    After a brief history of the development of the Section des Molecules marquees of the French Atomic Energy Commission, the author gives an outline of the synthesis of the following labelled compounds: benzene 14 C-6; phenyl-p-fluorophenyl, thienyl-2 β alanines β 14 C; noradrenaline β 14 C (arterenol β 14 C), dotriacontane 14 C-16-17, aminoethane sulfinic acid (hypotaurine 35 S). (author) [fr

  19. Synthesis of Zeolites Using the ADOR (Assembly-Disassembly-Organization-Reassembly) Route

    Czech Academy of Sciences Publication Activity Database

    Wheatley, P. S.; Čejka, Jiří; Morris, R. E.

    2016-01-01

    Roč. 2016, č. 110 (2016), č. článku e53463. ISSN 1940-087X R&D Projects: GA ČR GBP106/12/G015 EU Projects: European Commission(XE) 604307 - CASCATBEL Institutional support: RVO:61388955 Keywords : Chemistry * zeolites * synthesis * ADOR mechanism Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.232, year: 2016

  20. Use of protein cages as a template for confined synthesis of inorganic and organic nanoparticles.

    Science.gov (United States)

    Uchida, Masaki; Qazi, Shefah; Edwards, Ethan; Douglas, Trevor

    2015-01-01

    Protein cages are hollow spherical proteins assembled from a defined number of subunits. Because they are extremely homogeneous in size and structure, their interior cavities can serve as ideal templates to encapsulate and synthesize well-defined nanoparticles. Here, we describe the exemplary synthesis of a hard and a soft material in two representative protein cages, i.e., magnetite nanoparticles in ferritin and a poly(2-aminoethyl)methacrylate inside a viral capsid derived from the bacteriophage P22.

  1. Ecology man as an interdisciplsnary perspective directions synthesis and organization of scientific knowledge

    OpenAIRE

    Дуднікова, І. І.

    2015-01-01

    The paper analyzes the theoretical and methodological foundations of human ecology is an interdisciplinary perspective direction and synthesis of scientific knowledge in the context of which analyzes the problems of man and nature, man and society, global issues lyudstva. Meta research - to analyze human ecology as a new research direction for what roanalizovano conditions of human ecology and the problems that it rozlyadaye; The main problems of human ecology; uncover ways and ways to increa...

  2. Primordial soup was edible: abiotically produced Miller-Urey mixture supports bacterial growth.

    Science.gov (United States)

    Xie, Xueshu; Backman, Daniel; Lebedev, Albert T; Artaev, Viatcheslav B; Jiang, Liying; Ilag, Leopold L; Zubarev, Roman A

    2015-09-28

    Sixty years after the seminal Miller-Urey experiment that abiotically produced a mixture of racemized amino acids, we provide a definite proof that this primordial soup, when properly cooked, was edible for primitive organisms. Direct admixture of even small amounts of Miller-Urey mixture strongly inhibits E. coli bacteria growth due to the toxicity of abundant components, such as cyanides. However, these toxic compounds are both volatile and extremely reactive, while bacteria are highly capable of adaptation. Consequently, after bacterial adaptation to a mixture of the two most abundant abiotic amino acids, glycine and racemized alanine, dried and reconstituted MU soup was found to support bacterial growth and even accelerate it compared to a simple mixture of the two amino acids. Therefore, primordial Miller-Urey soup was perfectly suitable as a growth media for early life forms.

  3. Evolution and Adaptation of Wild Emmer Wheat Populations to Biotic and Abiotic Stresses.

    Science.gov (United States)

    Huang, Lin; Raats, Dina; Sela, Hanan; Klymiuk, Valentina; Lidzbarsky, Gabriel; Feng, Lihua; Krugman, Tamar; Fahima, Tzion

    2016-08-04

    The genetic bottlenecks associated with plant domestication and subsequent selection in man-made agroecosystems have limited the genetic diversity of modern crops and increased their vulnerability to environmental stresses. Wild emmer wheat, the tetraploid progenitor of domesticated wheat, distributed along a wide range of ecogeographical conditions in the Fertile Crescent, has valuable "left behind" adaptive diversity to multiple diseases and environmental stresses. The biotic and abiotic stress responses are conferred by series of genes and quantitative trait loci (QTLs) that control complex resistance pathways. The study of genetic diversity, genomic organization, expression profiles, protein structure and function of biotic and abiotic stress-resistance genes, and QTLs could shed light on the evolutionary history and adaptation mechanisms of wild emmer populations for their natural habitats. The continuous evolution and adaptation of wild emmer to the changing environment provide novel solutions that can contribute to safeguarding food for the rapidly growing human population.

  4. daf-16/FoxO promotes gluconeogenesis and trehalose synthesis during starvation to support survival.

    Science.gov (United States)

    Hibshman, Jonathan D; Doan, Alexander E; Moore, Brad T; Kaplan, Rebecca Ew; Hung, Anthony; Webster, Amy K; Bhatt, Dhaval P; Chitrakar, Rojin; Hirschey, Matthew D; Baugh, L Ryan

    2017-10-24

    daf-16 /FoxO is required to survive starvation in Caenorhabditis elegans , but how daf-16I FoxO promotes starvation resistance is unclear. We show that daf-16 /FoxO restructures carbohydrate metabolism by driving carbon flux through the glyoxylate shunt and gluconeogenesis and into synthesis of trehalose, a disaccharide of glucose. Trehalose is a well-known stress protectant, capable of preserving membrane organization and protein structure during abiotic stress. Metabolomic, genetic, and pharmacological analyses confirm increased trehalose synthesis and further show that trehalose not only supports survival as a stress protectant but also serves as a glycolytic input. Furthermore, we provide evidence that metabolic cycling between trehalose and glucose is necessary for this dual function of trehalose. This work demonstrates that daf-16 /FoxO promotes starvation resistance by shifting carbon metabolism to drive trehalose synthesis, which in turn supports survival by providing an energy source and acting as a stress protectant.

  5. daf-16/FoxO promotes gluconeogenesis and trehalose synthesis during starvation to support survival

    Science.gov (United States)

    Hibshman, Jonathan D; Doan, Alexander E; Moore, Brad T; Kaplan, Rebecca EW; Hung, Anthony; Webster, Amy K; Bhatt, Dhaval P; Chitrakar, Rojin; Hirschey, Matthew D

    2017-01-01

    daf-16/FoxO is required to survive starvation in Caenorhabditis elegans, but how daf-16IFoxO promotes starvation resistance is unclear. We show that daf-16/FoxO restructures carbohydrate metabolism by driving carbon flux through the glyoxylate shunt and gluconeogenesis and into synthesis of trehalose, a disaccharide of glucose. Trehalose is a well-known stress protectant, capable of preserving membrane organization and protein structure during abiotic stress. Metabolomic, genetic, and pharmacological analyses confirm increased trehalose synthesis and further show that trehalose not only supports survival as a stress protectant but also serves as a glycolytic input. Furthermore, we provide evidence that metabolic cycling between trehalose and glucose is necessary for this dual function of trehalose. This work demonstrates that daf-16/FoxO promotes starvation resistance by shifting carbon metabolism to drive trehalose synthesis, which in turn supports survival by providing an energy source and acting as a stress protectant. PMID:29063832

  6. Understanding the Posttranscriptional Regulation of Plant Responses to Abiotic Stress

    KAUST Repository

    Alshareef, Sahar

    2017-01-01

    Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and biotic and abiotic stresses

  7. Origin of Abiotic Methane in Submarine Hydrothermal Systems

    Science.gov (United States)

    Seewald, J. S.; German, C. R.; Grozeva, N. G.; Klein, F.; McDermott, J. M.; Ono, S.; Reeves, E. P.; Wang, D. T.

    2018-05-01

    Results of recent investigations into the chemical and isotopic composition of actively venting submarine hydrothermal fluids and volatile species trapped in fluid inclusions will be discussed in the context of processes responsible for abiotic CH4 formation.

  8. The Abiotic Depletion Potential: Background, Updates, and Future

    Directory of Open Access Journals (Sweden)

    Lauran van Oers

    2016-03-01

    Full Text Available Depletion of abiotic resources is a much disputed impact category in life cycle assessment (LCA. The reason is that the problem can be defined in different ways. Furthermore, within a specified problem definition, many choices can still be made regarding which parameters to include in the characterization model and which data to use. This article gives an overview of the problem definition and the choices that have been made when defining the abiotic depletion potentials (ADPs for a characterization model for abiotic resource depletion in LCA. Updates of the ADPs since 2002 are also briefly discussed. Finally, some possible new developments of the impact category of abiotic resource depletion are suggested, such as redefining the depletion problem as a dilution problem. This means taking the reserves in the environment and the economy into account in the reserve parameter and using leakage from the economy, instead of extraction rate, as a dilution parameter.

  9. [Inhibitors of proteolytic enzymes under abiotic stresses in plants (review)].

    Science.gov (United States)

    Mosolov, V V; Valueva, T A

    2011-01-01

    Data on the role of proteolytic enzyme inhibitors in plant adaptation to various unfavorable environmental abiotic factors--water deficiency, salinization of soil, extreme temperatures, etc.--and also probable functions of proteinases inhibitors in natural plant senescense are considered.

  10. Nucleotide Selectivity in Abiotic RNA Polymerization Reactions

    Science.gov (United States)

    Coari, Kristin M.; Martin, Rebecca C.; Jain, Kopal; McGown, Linda B.

    2017-09-01

    In order to establish an RNA world on early Earth, the nucleotides must form polymers through chemical rather than biochemical reactions. The polymerization products must be long enough to perform catalytic functions, including self-replication, and to preserve genetic information. These functions depend not only on the length of the polymers, but also on their sequences. To date, studies of abiotic RNA polymerization generally have focused on routes to polymerization of a single nucleotide and lengths of the homopolymer products. Less work has been done the selectivity of the reaction toward incorporation of some nucleotides over others in nucleotide mixtures. Such information is an essential step toward understanding the chemical evolution of RNA. To address this question, in the present work RNA polymerization reactions were performed in the presence of montmorillonite clay catalyst. The nucleotides included the monophosphates of adenosine, cytosine, guanosine, uridine and inosine. Experiments included reactions of mixtures of an imidazole-activated nucleotide (ImpX) with one or more unactivated nucleotides (XMP), of two or more ImpX, and of XMP that were activated in situ in the polymerization reaction itself. The reaction products were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the lengths and nucleotide compositions of the polymerization products. The results show that the extent of polymerization, the degree of heteropolymerization vs. homopolymerization, and the composition of the polymeric products all vary among the different nucleotides and depend upon which nucleotides and how many different nucleotides are present in the mixture.

  11. Nucleotide Selectivity in Abiotic RNA Polymerization Reactions.

    Science.gov (United States)

    Coari, Kristin M; Martin, Rebecca C; Jain, Kopal; McGown, Linda B

    2017-09-01

    In order to establish an RNA world on early Earth, the nucleotides must form polymers through chemical rather than biochemical reactions. The polymerization products must be long enough to perform catalytic functions, including self-replication, and to preserve genetic information. These functions depend not only on the length of the polymers, but also on their sequences. To date, studies of abiotic RNA polymerization generally have focused on routes to polymerization of a single nucleotide and lengths of the homopolymer products. Less work has been done the selectivity of the reaction toward incorporation of some nucleotides over others in nucleotide mixtures. Such information is an essential step toward understanding the chemical evolution of RNA. To address this question, in the present work RNA polymerization reactions were performed in the presence of montmorillonite clay catalyst. The nucleotides included the monophosphates of adenosine, cytosine, guanosine, uridine and inosine. Experiments included reactions of mixtures of an imidazole-activated nucleotide (ImpX) with one or more unactivated nucleotides (XMP), of two or more ImpX, and of XMP that were activated in situ in the polymerization reaction itself. The reaction products were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the lengths and nucleotide compositions of the polymerization products. The results show that the extent of polymerization, the degree of heteropolymerization vs. homopolymerization, and the composition of the polymeric products all vary among the different nucleotides and depend upon which nucleotides and how many different nucleotides are present in the mixture.

  12. Abiotic stress miRNomes in the Triticeae

    OpenAIRE

    Alptekin, Burcu; Langridge, Peter; Budak, Hikmet

    2016-01-01

    The continued growth in world population necessitates increases in both the quantity and quality of agricultural production. Triticeae members, particularly wheat and barley, make an important contribution to world food reserves by providing rich sources of carbohydrate and protein. These crops are grown over diverse production environments that are characterized by a range of environmental or abiotic stresses. Abiotic stresses such as drought, heat, salinity, or nutrient deficiencies and tox...

  13. Atmospheric Prebiotic Chemistry and Organic Hazes

    Science.gov (United States)

    Trainer, Melissa G.

    2012-01-01

    Earth's atmospheric composition at the time of the origin of life is not known, but it has often been suggested that chemical transformation of reactive species in the atmosphere was a significant source of pre biotic organic molecules. Experimental and theoretical studies over the past half century have shown that atmospheric synthesis can yield molecules such as amino acids and nucleobases, but these processes are very sensitive to gas composition and energy source. Abiotic synthesis of organic molecules is more productive in reduced atmospheres, yet the primitive Earth may not have been as reducing as earlier workers assumed, and recent research has reflected this shift in thinking. This work provides a survey of the range of chemical products that can be produced given a set of atmospheric conditions, with a particular focus on recent reports. Intertwined with the discussion of atmospheric synthesis is the consideration of an organic haze layer, which has been suggested as a possible ultraviolet shield on the anoxic early Earth. Since such a haze layer - if formed - would serve as a reservoir for organic molecules, the chemical composition of the aerosol should be closely examined. The results highlighted here show that a variety of products can be formed in mildly reducing or even neutral atmospheres, demonstrating that contributions of atmospheric synthesis to the organic inventory on early Earth should not be discounted. This review intends to bridge current knowledge of the range of possible atmospheric conditions in the prebiotic environment and pathways for synthesis under such conditions by examining the possible products of organic chemistry in the early atmosphere.

  14. How to prevent dimerization of laser dyes in water? Simulation and organic synthesis

    International Nuclear Information System (INIS)

    Dare-Doyen, S.

    2000-01-01

    Xanthenes are widely used as laser dyes in ethanol medium because their photophysical properties there are excellent. On the other hand, when they are dissolved in water, their fluorescence is almost zero on account of the dimerization phenomenon (aggregation of two molecules) which is specific in water although the interaction between the two molecules (these dyes are mainly cations) be repulsive. The first part of this work deals with the dimerization study of two dyes, the 6G rhodamine and the 6G pyronine. Molecular dynamics simulation results (AMBER software) have been compared with those of the NMR; thus it has been possible to describe the geometry of the 6G rhodamine dimer and to identify two structures present in equal quantities for the 6G pyronine dimer. It has been demonstrated that the role of water is essential in the aggregation mechanism; this role can be understood as resulting of the hydrophobic effect. The second part of this work concerns the synthesis of rhodamines which are soluble but not able to dimerize in water at the running concentrations of the laser dyes. At first, aminophenol precursors having hydrophilic ionic groups on modifiable sites have been synthesized without changing their photophysical properties. The synthesis sequence of the 3-(2-alkylamino-4-hydroxyphenyl)propionic acids has not given the waited products but N-(3'-hydroxyphenyl)amino-alkylsulfonic acids have been obtained. Their condensation with the phthalic anhydride has led to dyes of a charge -2 at a pH of 5 in water and which have photophysical properties similar to those of the rhodamine 575 in ethanol and laser emission properties in the emission spectral range of the rhodamine 6G in ethanol. This synthesis work has then led to the preparation of two laser dyes usable in water. (author) [fr

  15. Organotrichlorogermane synthesis by the reaction of elemental germanium, tetrachlorogermane and organic chloride via dichlorogermylene intermediate.

    Science.gov (United States)

    Okamoto, Masaki; Asano, Takuya; Suzuki, Eiichi

    2004-08-07

    Organotrichlorogermanes were synthesized by the reaction of elemental germanium, tetrachlorogermane and organic chlorides, methyl, propyl, isopropyl and allyl chlorides. Dichlorogermylene formed by the reaction of elemental germanium with tetrachlorogermane was the reaction intermediate, which was inserted into the carbon-chlorine bond of the organic chloride to give organotrichlorogermane. When isopropyl or allyl chloride was used as an organic chloride, organotrichlorogermane was formed also in the absence of tetrachlorogermane. These chlorides were converted to hydrogen chloride, which subsequently reacted with elemental germanium to give the dichlorogermylene intermediate. The reaction of elemental germanium, tetrachlorogermane and organic chlorides provides a simple and easy method for synthesizing organotrichlorogermanes, and all the raw materials are easily available.

  16. Electrochemical Synthesis of a Microporous Conductive Polymer Based on a Metal-Organic Framework Thin Film

    KAUST Repository

    Lu, Chunjing

    2014-05-22

    A new approach to preparing 3D microporous conductive polymer has been demonstrated in the electrochemical synthesis of a porous polyaniline network with the utilization of a MOF thin film supported on a conducting substrate. The prepared porous polyaniline with well-defined uniform micropores of 0.84 nm exhibits a high BET surface area of 986 m2 g−1 and a high electric conductivity of 0.125 S cm−1 when doped with I2, which is superior to existing porous conducting materials of porous MOFs, CMPs, and COFs.

  17. Synthesis, crystal growth, structural and physicochemical studies of novel binary organic complex: 4-chloroaniline-3-hydroxy-4-methoxybenzaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, K.P.; Reddi, R.S.B.; Bhattacharya, S. [Department of Chemistry, Centre of Advance Study, Banaras Hindu University, Varanasi-221005 (India); Rai, R.N., E-mail: rn_rai@yahoo.co.in [Department of Chemistry, Centre of Advance Study, Banaras Hindu University, Varanasi-221005 (India)

    2012-06-15

    The solid-state reaction, which is solvent free and green synthesis, has been adopted to explore the novel compound. The phase diagram of 4-chloroaniline (CA) and 3-hydroxy-4-methoxybenzaldehyde (HMB) system shows the formation of a novel 1:1 molecular complex, and two eutectics on either sides of complex. Thermochemical studies of complex and eutectics have been carried out for various properties such as heat of fusion, entropy of fusion, Jackson's parameters, interfacial energy and excess thermodynamic functions. The formation of molecular complex was also studied by IR, NMR, elemental analysis and UV-Vis absorption spectra. The single crystal of molecular complex was grown and its XRD study confirms the formation of complex and identifies the crystal structure and atomic packing of crystal of complex. Transmission spectra of grown crystal of the complex show 70% transmittance efficiency with cut off wavelength 412 nm. The band gap and refractive index of the crystal of complex have also been studied. - Graphical abstarct: Exploiting phase diagram study and solvent free synthesis a novel compound was synthesized and its single crystal growth, atomic packing, energy band gap and refractive index were studied. Highlights: Black-Right-Pointing-Pointer Novel organic complex was synthesized using Green or solvent free synthesis. Black-Right-Pointing-Pointer Phase diagram study provided the information to identify the worthy composition of novel complex. Black-Right-Pointing-Pointer The single crystal of the sufficient size was grown from the ethanol solution. Black-Right-Pointing-Pointer Crystal analysis suggested that the covalent bond is formed between the two parent compounds. Black-Right-Pointing-Pointer The transmittance of the crystal was found to be 70% and it was transparent from 412 to 850 nm.

  18. Synthesis, crystal growth, structural and physicochemical studies of novel binary organic complex: 4-chloroaniline–3-hydroxy-4-methoxybenzaldehyde

    International Nuclear Information System (INIS)

    Sharma, K.P.; Reddi, R.S.B.; Bhattacharya, S.; Rai, R.N.

    2012-01-01

    The solid-state reaction, which is solvent free and green synthesis, has been adopted to explore the novel compound. The phase diagram of 4-chloroaniline (CA) and 3-hydroxy-4-methoxybenzaldehyde (HMB) system shows the formation of a novel 1:1 molecular complex, and two eutectics on either sides of complex. Thermochemical studies of complex and eutectics have been carried out for various properties such as heat of fusion, entropy of fusion, Jackson's parameters, interfacial energy and excess thermodynamic functions. The formation of molecular complex was also studied by IR, NMR, elemental analysis and UV–Vis absorption spectra. The single crystal of molecular complex was grown and its XRD study confirms the formation of complex and identifies the crystal structure and atomic packing of crystal of complex. Transmission spectra of grown crystal of the complex show 70% transmittance efficiency with cut off wavelength 412 nm. The band gap and refractive index of the crystal of complex have also been studied. - Graphical abstarct: Exploiting phase diagram study and solvent free synthesis a novel compound was synthesized and its single crystal growth, atomic packing, energy band gap and refractive index were studied. Highlights: ► Novel organic complex was synthesized using Green or solvent free synthesis. ► Phase diagram study provided the information to identify the worthy composition of novel complex. ► The single crystal of the sufficient size was grown from the ethanol solution. ► Crystal analysis suggested that the covalent bond is formed between the two parent compounds. ► The transmittance of the crystal was found to be 70% and it was transparent from 412 to 850 nm.

  19. Abiotic and microbial interactions during anaerobic transformations of Fe(II and NOx-

    Directory of Open Access Journals (Sweden)

    Flynn ePicardal

    2012-03-01

    Full Text Available Microbial Fe(II oxidation using NO3- as the terminal electron acceptor (nitrate-dependent Fe(II oxidation; NDFO has been studied for over 15 years. Although there are reports of autotrophic isolates and stable enrichments, many of the bacteria capable of NDFO are known organotrophic NO3- -reducers that require the presence of an organic, primary substrate, e.g., acetate, for significant amounts of Fe(II oxidation. Although the thermodynamics of Fe(II oxidation are favorable when coupled to either NO3- or NO2- reduction, the kinetics of abiotic Fe(II oxidation by NO3- are relatively slow except under special conditions. NDFO is typically studied in batch cultures containing millimolar concentrations of Fe(II, NO3-, and the primary substrate. In such systems, NO2- is often observed to accumulate in culture media during Fe(II oxidation. Compared to NO3-, abiotic reactions of biogenic NO2- and Fe(II are relatively rapid. The kinetics and reaction pathways of Fe(II oxidation by NO2- are strongly affected by medium composition and pH, reactant concentration, and the presence of Fe(II-sorptive surfaces, e.g., Fe(III oxyhydroxides and cellular surfaces. In batch cultures, the combination of abiotic and microbial Fe(II oxidation can alter product distribution and, more importantly, results in the formation of intracellular precipitates and extracellular Fe(III oxyhydroxide encrustations that apparently limit further cell growth and Fe(II oxidation. Unless steps are taken to minimize or account for potential abiotic reactions, results of microbial NDFO studies can be obfuscated by artifacts of the chosen experimental conditions, the use of inappropriate analytical methods, and the resulting uncertainties about the relative importance of abiotic and microbial reactions.In this manuscript, abiotic reactions of NO3- and NO2- with aqueous Fe2+, chelated Fe(II, and solid-phase Fe(II are reviewed along with factors that can influence overall NDFO reac

  20. Ultrasound-assisted synthesis of nano-structured Zinc(II)-based metal-organic frameworks as precursors for the synthesis of ZnO nano-structures.

    Science.gov (United States)

    Bigdeli, Fahime; Ghasempour, Hosein; Azhdari Tehrani, Alireza; Morsali, Ali; Hosseini-Monfared, Hassan

    2017-07-01

    A 3D, porous Zn(II)-based metal-organic framework {[Zn 2 (oba) 2 (4-bpmn)]·(DMF) 1.5 } n (TMU-21), (4-bpmn=N,N'-Bis-pyridin-4-ylmethylene-naphtalene-1,5-diamine, H 2 oba=4,4'-oxybis(benzoic acid)) with nano-rods morphology under ultrasonic irradiation at ambient temperature and atmospheric pressure was prepared and characterized by scanning electron microscopy. Sonication time and concentration of initial reagents effects on the size and morphology of nano-structured MOFs were studied. Also {[Zn 2 (oba) 2 (4-bpmn)] (TMU-21) and {[Zn 2 (oba) 2 (4-bpmb)] (TMU-6), 4-bpmb=N,N'-(1,4-phenylene)bis(1-(pyridin-4-yl)methanimine) were easily prepared by mechanochemical synthesis. Nanostructures of Zinc(II) oxide were obtained by calcination of these compounds and their de-solvated analogue as activated MOFs, at 550°C under air atmosphere. As a result of that, different Nanostructures of Zinc(II) oxide were obtained. The ZnO nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Synthesis and characterization of [BMIM]bromide using microwave-assisted organic synthesis method and its application for dissolution of palm empty fruit bunch

    International Nuclear Information System (INIS)

    Arianie, Lucy; Wahyuningrum, Deana; Nurrachman, Zeily; Natalia, Dessy

    2014-01-01

    The decrease of cellulose crystallinity index of palm empty fruit bunch is crucial for the next application of cellulose as raw material for various biofuel and its derivatives. The aim of this research is to decrease the cellulose crystallinity index of palm empty fruit bunch using 1-butyl-3-methylimidazoliumbromide or [BMIM] bromide which has been synthesized using Microwave-Assisted Organic Synthesis (MAOS) method. Conventional reaction method has also been carried out to synthesize [BMIM]bromide for comparison as well. The characterization of synthesized product using FTIR, 1 H-NMR, 13 C-NMR and LC-MS showed that these reactions have been carried out successfully. The results showed that MAOS method is up to 90% faster in producing [BMIM]bromide compare to the conventional method. The application of [BMIM]bromide for dissolution of palm empty fruit bunch showed that cellulose and lignin could be extracted using stirring process for 20 hours. The decrease of cellulose crystallinity index and its morphology changes were identified using FTIR and Scanning Electron Microscope

  2. Synthesis and characterization of [BMIM]bromide using microwave-assisted organic synthesis method and its application for dissolution of palm empty fruit bunch

    Energy Technology Data Exchange (ETDEWEB)

    Arianie, Lucy, E-mail: lucy205@yahoo.com [Department of Chemistry, Faculty of Mathematics and Natural Science, Universitas Tanjungpura, Jl. A.Yani, 73 Pontianak 78124 (Indonesia); Wahyuningrum, Deana, E-mail: deana@chem.itb.ac.id; Nurrachman, Zeily, E-mail: deana@chem.itb.ac.id; Natalia, Dessy, E-mail: deana@chem.itb.ac.id [Department of Chemistry, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132 (Indonesia)

    2014-03-24

    The decrease of cellulose crystallinity index of palm empty fruit bunch is crucial for the next application of cellulose as raw material for various biofuel and its derivatives. The aim of this research is to decrease the cellulose crystallinity index of palm empty fruit bunch using 1-butyl-3-methylimidazoliumbromide or [BMIM] bromide which has been synthesized using Microwave-Assisted Organic Synthesis (MAOS) method. Conventional reaction method has also been carried out to synthesize [BMIM]bromide for comparison as well. The characterization of synthesized product using FTIR, {sup 1}H-NMR, {sup 13}C-NMR and LC-MS showed that these reactions have been carried out successfully. The results showed that MAOS method is up to 90% faster in producing [BMIM]bromide compare to the conventional method. The application of [BMIM]bromide for dissolution of palm empty fruit bunch showed that cellulose and lignin could be extracted using stirring process for 20 hours. The decrease of cellulose crystallinity index and its morphology changes were identified using FTIR and Scanning Electron Microscope.

  3. Organic Materials in the Undergraduate Laboratory: Microscale Synthesis and Investigation of a Donor-Acceptor Molecule

    Science.gov (United States)

    Pappenfus, Ted M.; Schliep, Karl B.; Dissanayake, Anudaththa; Ludden, Trevor; Nieto-Ortega, Belen; Lopez Navarrete, Juan T.; Ruiz Delgado, M. Carmen; Casado, Juan

    2012-01-01

    A series of experiments for undergraduate courses (e.g., organic, physical) have been developed in the area of small molecule organic materials. These experiments focus on understanding the electronic and redox properties of a donor-acceptor molecule that is prepared in a convenient one-step microscale reaction. The resulting intensely colored…

  4. Synthesis, Processing, and Characterization of Inorganic-Organic Hybrid Cross-Linked Silica, Organic Polyimide, and Inorganic Aluminosilicate Aerogels

    Science.gov (United States)

    Nguyen, Baochau N.; Guo, Haiquan N.; McCorkle, Linda S.

    2014-01-01

    As aerospace applications become ever more demanding, novel insulation materials with lower thermal conductivity, lighter weight and higher use temperature are required to fit the aerospace application needs. Having nanopores and high porosity, aerogels are superior thermal insulators, among other things. The use of silica aerogels in general is quite restricted due to their inherent fragility, hygroscopic nature, and poor mechanical properties, especially in extereme aerospace environments. Our research goal is to develop aerogels with better mechanical and environmental stability for a variety of aeronautic and space applications including space suit insulation for planetary surface missions, insulation for inflatable structures for habitats, inflatable aerodynamic decelerators for entry, descent and landing (EDL) operations, and cryotank insulation for advance space propulsion systems. Different type of aerogels including organic-inorganic polymer reinforced (hybrid) silica-based aerogels, polyimide aerogels and inorganic aluminosilicate aerogels have been developed and examined.

  5. Microwave-assisted synthesis of iron oxide nanoparticles in biocompatible organic environment

    Directory of Open Access Journals (Sweden)

    E. Aivazoglou

    2018-04-01

    Full Text Available The development of magnetite and maghemite particles in uniform nanometer size has triggered the interest of the research community due to their many interesting properties leading to a wide range of applications, such as catalysis, nanomedicine-nanobiology and other engineering applications. In this study, a simple, time-saving and low energy-consuming, microwave-assisted synthesis of iron oxide nanoparticles, is presented. The nanoparticles were prepared by microwave-assisted synthesis using polyethylene glycol (PEG or PEG and β-cyclodextrin (β-CD/water solutions of chloride salts of iron in the presence of ammonia solution. The prepared nano-powders were characterized using X-Ray Diffraction (XRD, Transition Electron Microscopy (TEM, Fourier-transform Infrared Spectroscopy (FTIR, Raman Spectroscopy, Vibrating Sample Magnetometer (VSM, X-Ray Photoelectron Spectroscopy (XPS and Thermal analysis (TG/DSC. The produced nanoparticles are crystallized mostly in the magnetite and maghemite lattice exhibiting very similar shape and size, with indications of partial PEG coating. Heating time, microwave power and presence of PEG, are the key factors shaping the size properties of nanoparticles. The average size of particles ranges from 10.3 to 19.2 nm. The nanoparticles exhibit a faceted morphology, with zero contamination levels. The magnetic measurements indicate that the powders are soft magnetic materials with negligible coercivity and remanence, illustrating super-paramagnetic behavior.

  6. Microwave-assisted synthesis of iron oxide nanoparticles in biocompatible organic environment

    Science.gov (United States)

    Aivazoglou, E.; Metaxa, E.; Hristoforou, E.

    2018-04-01

    The development of magnetite and maghemite particles in uniform nanometer size has triggered the interest of the research community due to their many interesting properties leading to a wide range of applications, such as catalysis, nanomedicine-nanobiology and other engineering applications. In this study, a simple, time-saving and low energy-consuming, microwave-assisted synthesis of iron oxide nanoparticles, is presented. The nanoparticles were prepared by microwave-assisted synthesis using polyethylene glycol (PEG) or PEG and β-cyclodextrin (β-CD)/water solutions of chloride salts of iron in the presence of ammonia solution. The prepared nano-powders were characterized using X-Ray Diffraction (XRD), Transition Electron Microscopy (TEM), Fourier-transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, Vibrating Sample Magnetometer (VSM), X-Ray Photoelectron Spectroscopy (XPS) and Thermal analysis (TG/DSC). The produced nanoparticles are crystallized mostly in the magnetite and maghemite lattice exhibiting very similar shape and size, with indications of partial PEG coating. Heating time, microwave power and presence of PEG, are the key factors shaping the size properties of nanoparticles. The average size of particles ranges from 10.3 to 19.2 nm. The nanoparticles exhibit a faceted morphology, with zero contamination levels. The magnetic measurements indicate that the powders are soft magnetic materials with negligible coercivity and remanence, illustrating super-paramagnetic behavior.

  7. Synthesis and Electrospraying of Nanoscale MOF (Metal Organic Framework) for High-Performance CO2 Adsorption Membrane

    Science.gov (United States)

    Wahiduzzaman; Allmond, Kelsey; Stone, John; Harp, Spencer; Mujibur, Khan

    2017-01-01

    We report the sonochemical synthesis of MOF (metal organic framework) nanoparticles of 30-200 nm in size and electrospraying of those particles on electrospun nanofibers to process a MOF-attached nanofibrous membrane. This membrane displayed significant selectivity towards CO2 and capacity of adsorbing with 4000-5000 ppm difference from a mixed gas flow of 1% CO2 and 99% N2. Applying ultrasonic waves during the MOF synthesis offered rapid dispersion and formation of crystalline MOF nanoparticles in room temperature. The MOF nanoparticles of 100-200 nm in size displayed higher surface area and adsorption capacity comparing to that of 30-60 nm in size. Nanofibrous membrane was produced by electrospinning of MOF blended PAN solution followed by electrospraying of additional MOF nanoparticles. This yielded uniform MOF deposition on nanofibers, occurred due to electrostatic attraction between highly charged nanoparticles and conductive nanofibers. A test bench for real-time CO2 adsorption at room temperature was built with non-dispersive Infrared (NDIR) CO2 sensors. Comparative tests were performed on the membrane to investigate its enhanced adsorption capacity. Three layers of the as-produced membranes displayed CO2 adsorption for approximately 2 h. Thermogravimetric analysis (TGA) of the membrane showed the thermal stability of the MOF and PAN up to 290 and 425 °C, respectively.

  8. Mild Conditions for Deuteration of Primary and Secondary Arylamines for the Synthesis of Deuterated Optoelectronic Organic Molecules

    Directory of Open Access Journals (Sweden)

    Anwen M. Krause-Heuer

    2014-11-01

    Full Text Available Deuterated arylamines demonstrate great potential for use in optoelectronic devices, but their widespread utility requires a method for large-scale synthesis. The incorporation of these deuterated materials into optoelectronic devices also provides the opportunity for studies of the functioning device using neutron reflectometry based on the difference in the scattering length density between protonated and deuterated compounds. Here we report mild deuteration conditions utilising standard laboratory glassware for the deuteration of: diphenylamine, N-phenylnaphthylamine, N-phenyl-o-phenylenediamine and 1-naphthylamine (via H/D exchange in D2O at 80 °C, catalysed by Pt/C and Pd/C. These conditions were not successful in the deuteration of triphenylamine or N,N-dimethylaniline, suggesting that these mild conditions are not suitable for the deuteration of tertiary arylamines, but are likely to be applicable for the deuteration of other primary and secondary arylamines. The deuterated arylamines can then be used for synthesis of larger organic molecules or polymers with optoelectronic applications.

  9. Synthesis, growth and characterization of organic nonlinear optical material: N-benzyl-2-methyl-4-nitroaniline (BNA)

    Science.gov (United States)

    Kalaivanan, R.; Srinivasan, K.

    2017-05-01

    Synthesis of the organic nonlinear optical compound N-benzyl-2-methyl-4-nitroaniline (BNA) was carried out in a newer chemical environment using the mixture of benzyl chloride and 2-methl-4-nitroaniline by a preferred laboratory synthesis process. The synthesized BNA compound was separated by column chromatography (CC) with low pressure silica gell using petrollium benzine and purity of the separated resultant product was confirmed by thin layer chromatography (TLC). Further, the material was recrystallized atleast four times in methanol and the highly purified BNA was used for the growth of single crystals from solutions with selected solvents by slow evaporation method at room temperature. Single crystals having natural growth morphology were harvested and their different growth faces were identified by optical goniometry. The grown crystals were subjected to different characterization techniques such as powder x-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and UV-vis-Near IR spectroscopy. Further, the second harmonic generation (SHG) efficiency of the grown BNA crystal was studied by Kurtz and Perry powder technique using Nd:YAG laser as fundamental source and found to be twice that of inorganic standard KDP.

  10. Diffusion Control in the in Situ Synthesis of Iconic Metal-Organic Frameworks within an Ionic Polymer Matrix.

    Science.gov (United States)

    Lim, Jungho; Lee, Eun Ji; Choi, Jae Sun; Jeong, Nak Cheon

    2018-01-31

    Ionic polymers that possess ion-exchangeable sites have been shown to be a greatly useful platform to fabricate mixed matrices (MMs) where metal-organic frameworks (MOFs) can be in situ synthesized, although the in situ synthesis of MOF has been rarely studied. In this study, alginate (ALG), an anionic green polymer that possesses metal-ion-exchangeable sites, is employed as a platform of MMs for the in situ synthesis of iconic MOFs, HKUST-1, and MOF-74(Zn). We demonstrate for the first time that the sequential order of supplying MOF ingredients (metal ion and deprotonated ligand) into the alginate matrix leads to substantially different results because of a difference in the diffusion of the MOF components. For the examples examined, whereas the infusion of BTC 3- ligand into Cu 2+ -exchanged ALG engendered the eggshell-shaped HKUST-1 layers on the surface of MM spheres, the infusion of Cu 2+ ions into BTC 3- -included alginate engendered the high dispersivity and junction contact of HKUST-1 crystals in the alginate matrix. This fundamental property has been exploited to fabricate a flexible MOF-containing mixed matrix membrane by coincorporating poly(vinyl alcohol). Using two molecular dyes, namely, methylene blue and rhodamine 6G, further, we show that this in situ strategy is suitable for fabricating an MOF-MM that exhibits size-selective molecular uptake.

  11. Strategies for Distinguishing Abiotic Chemistry from Martian Biochemistry in Samples Returned from Mars

    Science.gov (United States)

    Glavin, D. P.; Burton, A. S.; Callahan, M. P.; Elsila, J. E.; Stern, J. C.; Dworkin, J. P.

    2012-01-01

    A key goal in the search for evidence of extinct or extant life on Mars will be the identification of chemical biosignatures including complex organic molecules common to all life on Earth. These include amino acids, the monomer building blocks of proteins and enzymes, and nucleobases, which serve as the structural basis of information storage in DNA and RNA. However, many of these organic compounds can also be formed abiotically as demonstrated by their prevalence in carbonaceous meteorites [1]. Therefore, an important challenge in the search for evidence of life on Mars will be distinguishing between abiotic chemistry of either meteoritic or martian origin from any chemical biosignatures from an extinct or extant martian biota. Although current robotic missions to Mars, including the 2011 Mars Science Laboratory (MSL) and the planned 2018 ExoMars rovers, will have the analytical capability needed to identify these key classes of organic molecules if present [2,3], return of a diverse suite of martian samples to Earth would allow for much more intensive laboratory studies using a broad array of extraction protocols and state-of-theart analytical techniques for bulk and spatially resolved characterization, molecular detection, and isotopic and enantiomeric compositions that may be required for unambiguous confirmation of martian life. Here we will describe current state-of-the-art laboratory analytical techniques that have been used to characterize the abundance and distribution of amino acids and nucleobases in meteorites, Apollo samples, and comet- exposed materials returned by the Stardust mission with an emphasis on their molecular characteristics that can be used to distinguish abiotic chemistry from biochemistry as we know it. The study of organic compounds in carbonaceous meteorites is highly relevant to Mars sample return analysis, since exogenous organic matter should have accumulated in the martian regolith over the last several billion years and the

  12. Quantifying the degradation of organic matter in marine sediments: A review and synthesis

    Science.gov (United States)

    Arndt, Sandra; Jørgensen, B. B.; LaRowe, D. E.; Middelburg, J. J.; Pancost, R. D.; Regnier, P.

    2013-08-01

    Quantifying the rates of biogeochemical processes in marine sediments is essential for understanding global element cycles and climate change. Because organic matter degradation is the engine behind benthic dynamics, deciphering the impact that various forces have on this process is central to determining the evolution of the Earth system. Therefore, recent developments in the quantitative modeling of organic matter degradation in marine sediments are critically reviewed. The first part of the review synthesizes the main chemical, biological and physical factors that control organic matter degradation in sediments while the second part provides a general review of the mathematical formulations used to model these processes and the third part evaluates their application over different spatial and temporal scales. Key transport mechanisms in sedimentary environments are summarized and the mathematical formulation of the organic matter degradation rate law is described in detail. The roles of enzyme kinetics, bioenergetics, temperature and biomass growth in particular are highlighted. Alternative model approaches that quantify the degradation rate constant are also critically compared. In the third part of the review, the capability of different model approaches to extrapolate organic matter degradation rates over a broad range of temporal and spatial scales is assessed. In addition, the structure, functions and parameterization of more than 250 published models of organic matter degradation in marine sediments are analyzed. The large range of published model parameters illustrates the complex nature of organic matter dynamics, and, thus, the limited transferability of these parameters from one site to another. Compiled model parameters do not reveal a statistically significant correlation with single environmental characteristics such as water depth, deposition rate or organic matter flux. The lack of a generic framework that allows for model parameters to be

  13. Synthesis of a conjugated pyrrolopyridazinedione-benzodithiophene (PPD-BDT) copolymer and its application in organic and hybrid solar cells.

    Science.gov (United States)

    Knall, Astrid-Caroline; Jones, Andrew O F; Kunert, Birgit; Resel, Roland; Reishofer, David; Zach, Peter W; Kirkus, Mindaugas; McCulloch, Iain; Rath, Thomas

    2017-01-01

    Herein, we describe the synthesis and characterization of a conjugated donor-acceptor copolymer consisting of a pyrrolopyridazinedione (PPD) acceptor unit, and a benzodithiophene (BDT) donor unit. The polymerization was done via a Stille cross-coupling polycondensation. The resulting PPD-BDT copolymer revealed an optical bandgap of 1.8 eV and good processability from chlorobenzene solutions. In an organic solar cell in combination with PC 70 BM, the polymer led to a power conversion efficiency of 4.5%. Moreover, the performance of the copolymer was evaluated in polymer/nanocrystal hybrid solar cells using non-toxic CuInS 2 nanocrystals as inorganic phase, which were prepared from precursors directly in the polymer matrix without using additional capping ligands. The PPD-BDT/CuInS 2 hybrid solar cells showed comparably high photovoltages and a power conversion efficiency of 2.2%.

  14. Synthesis of a conjugated pyrrolopyridazinedione–benzodithiophene (PPD–BDT) copolymer and its application in organic and hybrid solar cells

    KAUST Repository

    Knall, Astrid-Caroline

    2017-03-30

    Herein, we describe the synthesis and characterization of a conjugated donor–acceptor copolymer consisting of a pyrrolopyridazinedione (PPD) acceptor unit, and a benzodithiophene (BDT) donor unit. The polymerization was done via a Stille cross-coupling polycondensation. The resulting PPD–BDT copolymer revealed an optical bandgap of 1.8 eV and good processability from chlorobenzene solutions. In an organic solar cell in combination with PC70BM, the polymer led to a power conversion efficiency of 4.5%. Moreover, the performance of the copolymer was evaluated in polymer/nanocrystal hybrid solar cells using non-toxic CuInS2 nanocrystals as inorganic phase, which were prepared from precursors directly in the polymer matrix without using additional capping ligands. The PPD–BDT/CuInS2 hybrid solar cells showed comparably high photovoltages and a power conversion efficiency of 2.2%.Graphical abstract

  15. Synthesis and characterization of a helicene-based imidazolium salt and its application in organic molecular electronics.

    Science.gov (United States)

    Storch, Jan; Zadny, Jaroslav; Strasak, Tomas; Kubala, Martin; Sykora, Jan; Dusek, Michal; Cirkva, Vladimir; Matejka, Pavel; Krbal, Milos; Vacek, Jan

    2015-02-02

    Herein we demonstrate the synthesis of a helicene-based imidazolium salt. The salt was prepared by starting from racemic 2-methyl[6]helicene, which undergoes radical bromination to yield 2-(bromomethyl)[6]helicene. Subsequent treatment with 1-butylimidazole leads to the corresponding salt 1-butyl-3-(2-methyl[6]helicenyl)-imidazolium bromide. The prepared salt was subsequently characterized by using NMR spectroscopy and X-ray analysis, various optical spectrometric techniques, and computational chemistry tools. Finally, the imidazolium salt was immobilized onto a SiO2 substrate as a crystalline or amorphous deposit. The deposited layers were used for the development of organic molecular semiconductor devices and the construction of a fully reversible humidity sensor. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Synthesis and evaluation of new organic and phosphorous derivatives against ionizing radiation: study of the in vitro mechanism of action

    International Nuclear Information System (INIS)

    Prouillac, C.

    2006-10-01

    This work falls under a research program. The aim was to synthesize new organic phosphorylated compounds having an interesting radio pharmacological activity without toxicity. That is why, we carried out the synthesis of new benzothiazole and thiadiazole N-substituted derivatives as thiols, amino thiols, acids thio-sulfonic and phosphoro thioates. All these compounds were characterized by NMR (proton, carbon, phosphorus, 2D), by mass spectrometry, elementary analyzes and for some of them by diffraction of x-rays. The activity of the majority of them was evaluated by in vitro tests. The experimental results were confirmed by theoretical study: the aim of D.F.T. calculation was the study of the mechanism of capture of the free radicals by our compounds. In addition, a study of relation structure activity (Q.S.A.R.) was carried out. Our results allow us to create a model making it possible to establish structure-activity relationship. (author)

  17. Autoradiographic demonstration of unscheduled DNA synthesis in oral tissues treated with chemical carcinogens in short-term organ culture

    International Nuclear Information System (INIS)

    Ide, F.; Umemura, S.; Ishikawa, T.; Takayama, S.

    1981-01-01

    A system in which oral tissues of inbred F344 adult rats and Syrian golden hamster embryos were used in combination with autoradiography was developed for measurement of unscheduled DNA synthesis (UDS). For this, oral mucosa, submandibular gland, tooth germ and mandible in short-term organ cultures were treated with 4-nitroquinoline l-oxide or N-methyl-N-nitrosourea plus (methyl- 3 H)thymidine. Significant numbers of silver grains, indicating UDS, were detected over the nuclei of cells of all these tissues except rat salivary gland after treatment with carcinogens. This autoradiographic method is suitable for detection of UDS in oral tissues in conditions mimicking those in vivo. Results obtained in this study indicated a potential use of this system for studies on the mechanism of carcinogenesis at a cellular level comparable to in vivo carcinogenesis studies on oral tissues. (author)

  18. Synthesis and characterization of a novel organic corrosion inhibitor for mild steel in 1 M hydrochloric acid

    Science.gov (United States)

    Ahmed, Mohammed H. Othman; Al-Amiery, Ahmed A.; Al-Majedy, Yasmin K.; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar; Gaaz, Tayser Sumer

    2018-03-01

    The synthesis and characterization of a novel organic corrosion inhibitor (4-(3-mercapto-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazin-6-yl)phenol), for mild steel in 1 M hydrochloric acid (HCl) has been successfully reported for the first time. The inhibitor evaluated as corrosion inhibitor for mild steel in 1 M of Hydrochloric acid solution using electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) measurement techniques. Changes in the impedance parameters suggested an adsorption of the inhibitor onto the mild steel surface, leading to the formation of protective films. The results show that the inhibition efficiencies increased with increasing the concentrations of the inhibitors and decreased with increasing temperature. The maximum inhibition efficiency up to 67% at the maximum concentration 0.5 mM. This shows that those inhibitors are effective in helping to reduce and slowing down the corrosion process that occurs to mild steel with a hydrochloric acid solution by providing an organic inhibitor for the mild steel that can be weakened by increasing the temperature. The adsorption process of the synthesized organic inhibitor depends on its electronic characteristics in addition to steric effects and the nature of metal surface, temperature degree and the varying degrees of surface-site activity. The synthesized inhibitor molecules were absorbed by metal surface and follow Langmuir isotherms.

  19. Synthesis and characterization of a novel organic corrosion inhibitor for mild steel in 1 M hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Mohammed H. Othman Ahmed

    2018-03-01

    Full Text Available The synthesis and characterization of a novel organic corrosion inhibitor (4-(3-mercapto-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazin-6-ylphenol, for mild steel in 1 M hydrochloric acid (HCl has been successfully reported for the first time. The inhibitor evaluated as corrosion inhibitor for mild steel in 1 M of Hydrochloric acid solution using electrochemical impedance spectroscopy (EIS, and electrochemical frequency modulation (EFM measurement techniques. Changes in the impedance parameters suggested an adsorption of the inhibitor onto the mild steel surface, leading to the formation of protective films. The results show that the inhibition efficiencies increased with increasing the concentrations of the inhibitors and decreased with increasing temperature. The maximum inhibition efficiency up to 67% at the maximum concentration 0.5 mM. This shows that those inhibitors are effective in helping to reduce and slowing down the corrosion process that occurs to mild steel with a hydrochloric acid solution by providing an organic inhibitor for the mild steel that can be weakened by increasing the temperature. The adsorption process of the synthesized organic inhibitor depends on its electronic characteristics in addition to steric effects and the nature of metal surface, temperature degree and the varying degrees of surface-site activity. The synthesized inhibitor molecules were absorbed by metal surface and follow Langmuir isotherms. Keywords: Corrosion, Inhibitor, Mild steel, EIS spectroscopy

  20. Bringing research into a first semester organic chemistry laboratory with the multistep synthesis of carbohydrate-based HIV inhibitor mimics.

    Science.gov (United States)

    Pontrello, Jason K

    2015-01-01

    Benefits of incorporating research experiences into laboratory courses have been well documented, yet examples of research projects designed for the first semester introductory organic chemistry lab course are extremely rare. To address this deficiency, a Carbohydrate-Based human immunodeficiency virus (HIV) Inhibitor project consisting of a synthetic scheme of four reactions was developed for and implemented in the first semester organic lab. Students carried out the synthetic reactions during the last 6 of 10 total labs in the course, generating carbohydrate-based dimeric target molecules modeled after published dimers with application in HIV therapy. The project was designed to provide a research experience through use of literature procedures for reactions performed, exploration of variation in linker length in the target structure, and synthesis of compounds not previously reported in the scientific literature. Project assessment revealed strong student support, indicating enhanced engagement and interest in the course as a direct result of the use of scientific literature and the applications of the synthesized carbohydrate-based molecules. Regardless of discussed challenges in designing a research project for the first semester lab course, the finding from data analysis that a project implemented in the first semester lab had significantly greater student impact than a second semester project should provide motivation for development of additional research projects for a first semester organic course. © 2015 The International Union of Biochemistry and Molecular Biology.

  1. Italian Chemists’ Contributions to Named Reactions in Organic Synthesis: An Historical Perspective

    Directory of Open Access Journals (Sweden)

    Gianluca Papeo

    2013-09-01

    Full Text Available From the second half of the 19th century up to modern times, the tremendous contribution of Italian chemists to the development of science resulted in the discovery of a number of innovative chemical transformations. These reactions were subsequently christened according to their inventors’ name and so entered into the organic chemistry portfolio of “named organic reactions”. As these discoveries were being conceived, massive social, political and geographical changes in these chemists’ homeland were also occurring. In this review, a brief survey of known (and some lesser known named organic reactions discovered by Italian chemists, along with their historical contextualization, is presented.

  2. Italian chemists' contributions to named reactions in organic synthesis: an historical perspective.

    Science.gov (United States)

    Papeo, Gianluca; Pulici, Maurizio

    2013-09-04

    From the second half of the 19th century up to modern times, the tremendous contribution of Italian chemists to the development of science resulted in the discovery of a number of innovative chemical transformations. These reactions were subsequently christened according to their inventors' name and so entered into the organic chemistry portfolio of "named organic reactions". As these discoveries were being conceived, massive social, political and geographical changes in these chemists' homeland were also occurring. In this review, a brief survey of known (and some lesser known) named organic reactions discovered by Italian chemists, along with their historical contextualization, is presented.

  3. Environmentally friendly synthesis of organic-soluble silver nanoparticles for printed electronics

    International Nuclear Information System (INIS)

    Lee, Kwi Jong; Jun, Byung Ho; Choi, Junrak; Lee, Young Il; Joung, Jaewoo; Oh, Yong Soo

    2007-01-01

    In this study, we attempted to synthesize organic-soluble silver nanoparticles in the concentrated organic phase with an environmentally friendly method. The fully organic phase system contains silver acetate as a silver precursor, oleic acid as both a medium and a capping molecule, and tin acetate as a reducing agent. Monodisperse silver nanoparticles with average diameters of ca. 5 nm can be easily synthesized at large scale. Only a small usage of tin acetate ( 90%). Also, it was investigated that the residual tin atom does not exist in the synthesized silver nanoparticles. This implied that tin acetate acts as a reducing catalyst

  4. MICROSCALE METABOLIC, REDOX AND ABIOTIC REACTIONS IN HANFORD 300 AREA SUBSURFACE SEDIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Beyenal, Haluk [WSU; McLEan, Jeff [JCVI; Majors, Paul [PNNL; Fredrickson, Jim [PNNL

    2013-11-14

    The Hanford 300 Area is a unique site due to periodic hydrologic influence of river water resulting in changes in groundwater elevation and flow direction. This area is also highly subject to uranium remobilization, the source of which is currently believed to be the region at the base of the vadose zone that is subject to period saturation due to the changes in the water levels in the Columbia River. We found that microbial processes and redox and abiotic reactions which operate at the microscale were critical to understanding factors controlling the macroscopic fate and transport of contaminants in the subsurface. The combined laboratory and field research showed how microscale conditions control uranium mobility and how biotic, abiotic and redox reactions relate to each other. Our findings extended the current knowledge to examine U(VI) reduction and immobilization using natural 300 Area communities as well as selected model organisms on redox-sensitive and redox-insensitive minerals. Using innovative techniques developed specifically to probe biogeochemical processes at the microscale, our research expanded our current understanding of the roles played by mineral surfaces, bacterial competition, and local biotic, abiotic and redox reaction rates on the reduction and immobilization of uranium.

  5. Metabolomics as a Tool to Investigate Abiotic Stress Tolerance in Plants

    Directory of Open Access Journals (Sweden)

    Aurelio Gómez-Cadenas

    2013-03-01

    Full Text Available Metabolites reflect the integration of gene expression, protein interaction and other different regulatory processes and are therefore closer to the phenotype than mRNA transcripts or proteins alone. Amongst all –omics technologies, metabolomics is the most transversal and can be applied to different organisms with little or no modifications. It has been successfully applied to the study of molecular phenotypes of plants in response to abiotic stress in order to find particular patterns associated to stress tolerance. These studies have highlighted the essential involvement of primary metabolites: sugars, amino acids and Krebs cycle intermediates as direct markers of photosynthetic dysfunction as well as effectors of osmotic readjustment. On the contrary, secondary metabolites are more specific of genera and species and respond to particular stress conditions as antioxidants, Reactive Oxygen Species (ROS scavengers, coenzymes, UV and excess radiation screen and also as regulatory molecules. In addition, the induction of secondary metabolites by several abiotic stress conditions could also be an effective mechanism of cross-protection against biotic threats, providing a link between abiotic and biotic stress responses. Moreover, the presence/absence and relative accumulation of certain metabolites along with gene expression data provides accurate markers (mQTL or MWAS for tolerant crop selection in breeding programs.

  6. Metal-Organic Frameworks: Building Block Design Strategies for the Synthesis of MOFs.

    KAUST Repository

    Luebke, Ryan

    2014-01-01

    A significant and ongoing challenge in materials chemistry and furthermore solid state chemistry is to design materials with the desired properties and characteristics. The field of Metal-Organic Frameworks (MOFs) offers several strategies

  7. Abstracts of the papers presented at the workshop 'synthesis and application of radioactively labelled organic compounds'

    International Nuclear Information System (INIS)

    1988-10-01

    The abstracts of the 12 papers read at the Rossendorf workshop comprise syntheses and radioactive labelling of organic compounds such as herbicides, steroids, peptides and others and their application as tracers, above all in kinetic studies

  8. Size controlled synthesis of Co nanoparticles by combination of organic solvent and surfactant

    International Nuclear Information System (INIS)

    Chen Yong; Liew, K.Y.; Li Jinlin

    2009-01-01

    Co particles were synthesized with mean particle sizes in the range of 3.2-171.4 nm in ambient atmosphere by reduction of cobalt salt with sodium borohydride as the reducing reagent, a combination of alcohols as solvents and a triblock copolymer P123 (EO 20 PO 70 EO 20 ) as the surfactant. The particle size and its distribution were controlled by varying the synthesis parameters such as the viscosity of the medium, the amount of alcohols or P123 in the reaction system. FT-IR and X-ray photoelectron spectroscopy (XPS) measurements confirmed the interaction between the oxygen atoms of P123 and Co 2+ or Co 0 . Detailed surface analyses by XPS and HRTEM revealed that the synthesized particles consisted of Co 0 metal surrounded by amorphous CoO, Co 2 B and chemisorbed P123.

  9. Synthesis and Identification of the Organic Reagent Ereochrom Black T and its Complex with Cobalt (lll

    Directory of Open Access Journals (Sweden)

    Jassem M. Abd Al Hassein

    2017-02-01

    Full Text Available The ligand 1–(4–Hydroxy –3–Naphthalene Azo–4–Nitro–8–Hydroxy–6–Sulfonic Naphthalene Acid Sodium Salt was synthesized (by the reaction between 3–amino–4– hydroxyl naphthalene and 3 – nitro – 7 – hydroxyl –5– sulfonic naphthalene acid sodium salt and characterized by FTIR technique, its ionization constants (PKs were determined. Synthesis and spectroscopic investigations of its complex with Co (III in aqueous solution revealed the sole formation of (1: 2 (metal: ligand complex. Specral and magnatic studies of the isolated complex indicates octahedral coordination via the N atoms of the azo groups and the O atoms of the hydroxyl groups. The molar conductivity of the complex was determined in an alcoholic solutions indicates that the complex has high molar conductivity. The magnetic properties were determined by using Gouy balance which indicates diamagnetic complex.

  10. Combinatorial synthesis by nature: volatile organic sulfur-containing constituents of Ruta chalepensis L.

    Science.gov (United States)

    Escher, Sina; Niclass, Yvan; van de Waal, Matthijs; Starkenmann, Christian

    2006-09-01

    Ongoing interest in discovering new natural fragrance and flavor ingredients prompted us to examine a solvent extract of sulfurous-sweaty smelling Ruta chalepensis L. (Rutaceae) plant material more closely. Twenty-one sulfur-containing constituents of similar structures were identified by GC/MS techniques. Amongst them, 14 have never been described to occur in nature. The compounds 1-18 belong to a family of natural flavor and fragrance molecules having a 1,3-positioned O,S moiety in common. The identities of the natural constituents were confirmed by comparison with synthetic reference samples, and the organoleptic properties of the latter were studied. The relative and absolute configurations of the four stereoisomers of 4-methyl-3-sulfanylhexan-1-ol (5) were established by stereoselective synthesis. The natural isomers consisted of a 65 : 35 mixture of (3R,4S)-5 and (3S,4S)-5.

  11. Synthesis and Evaluation of Porous Semiconductor Hexaniobate Nanotubes for Photolysis of Organic Dyes in Wastewater

    Directory of Open Access Journals (Sweden)

    Maryam Zarei-Chaleshtori

    2014-10-01

    Full Text Available We present the chemical synthesis of hexaniobate nanotubes using two routes, (1 starting material K4Nb6O17 and (2 parent material of H4Nb6O17 via ion exchange. The as-synthesized materials were exfoliated by adjusting the pH to 9–10 using tetra-n-butylammonioum hydroxide (TBA+OH−, leading to a formation of hexaniobate nanotubes. In order to understand morphology a full characterization was conducted using SEM, HRTEM, BET and powder-XRD. The photocatalytic activity was evaluated using photolysis method using Bromocresol Green (BG and Methyl Orange (MO as model contaminants. Results indicate a nanotube porous oxide with large porous and surface area; the photocatalytic activity is about 95% efficient when comparing with commercial TiO2.

  12. Digitization of multistep organic synthesis in reactionware for on-demand pharmaceuticals.

    Science.gov (United States)

    Kitson, Philip J; Marie, Guillaume; Francoia, Jean-Patrick; Zalesskiy, Sergey S; Sigerson, Ralph C; Mathieson, Jennifer S; Cronin, Leroy

    2018-01-19

    Chemical manufacturing is often done at large facilities that require a sizable capital investment and then produce key compounds for a finite period. We present an approach to the manufacturing of fine chemicals and pharmaceuticals in a self-contained plastic reactionware device. The device was designed and constructed by using a chemical to computer-automated design (ChemCAD) approach that enables the translation of traditional bench-scale synthesis into a platform-independent digital code. This in turn guides production of a three-dimensional printed device that encloses the entire synthetic route internally via simple operations. We demonstrate the approach for the γ-aminobutyric acid receptor agonist, (±)-baclofen, establishing a concept that paves the way for the local manufacture of drugs outside of specialist facilities. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  13. Coordinated Actions of Glyoxalase and Antioxidant Defense Systems in Conferring Abiotic Stress Tolerance in Plants

    Directory of Open Access Journals (Sweden)

    Mirza Hasanuzzaman

    2017-01-01

    Full Text Available Being sessile organisms, plants are frequently exposed to various environmental stresses that cause several physiological disorders and even death. Oxidative stress is one of the common consequences of abiotic stress in plants, which is caused by excess generation of reactive oxygen species (ROS. Sometimes ROS production exceeds the capacity of antioxidant defense systems, which leads to oxidative stress. In line with ROS, plants also produce a high amount of methylglyoxal (MG, which is an α-oxoaldehyde compound, highly reactive, cytotoxic, and produced via different enzymatic and non-enzymatic reactions. This MG can impair cells or cell components and can even destroy DNA or cause mutation. Under stress conditions, MG concentration in plants can be increased 2- to 6-fold compared with normal conditions depending on the plant species. However, plants have a system developed to detoxify this MG consisting of two major enzymes: glyoxalase I (Gly I and glyoxalase II (Gly II, and hence known as the glyoxalase system. Recently, a novel glyoxalase enzyme, named glyoxalase III (Gly III, has been detected in plants, providing a shorter pathway for MG detoxification, which is also a signpost in the research of abiotic stress tolerance. Glutathione (GSH acts as a co-factor for this system. Therefore, this system not only detoxifies MG but also plays a role in maintaining GSH homeostasis and subsequent ROS detoxification. Upregulation of both Gly I and Gly II as well as their overexpression in plant species showed enhanced tolerance to various abiotic stresses including salinity, drought, metal toxicity, and extreme temperature. In the past few decades, a considerable amount of reports have indicated that both antioxidant defense and glyoxalase systems have strong interactions in conferring abiotic stress tolerance in plants through the detoxification of ROS and MG. In this review, we will focus on the mechanisms of these interactions and the coordinated

  14. Coordinated Actions of Glyoxalase and Antioxidant Defense Systems in Conferring Abiotic Stress Tolerance in Plants

    Science.gov (United States)

    Hasanuzzaman, Mirza; Nahar, Kamrun; Hossain, Md. Shahadat; Mahmud, Jubayer Al; Rahman, Anisur; Inafuku, Masashi; Oku, Hirosuke; Fujita, Masayuki

    2017-01-01

    Being sessile organisms, plants are frequently exposed to various environmental stresses that cause several physiological disorders and even death. Oxidative stress is one of the common consequences of abiotic stress in plants, which is caused by excess generation of reactive oxygen species (ROS). Sometimes ROS production exceeds the capacity of antioxidant defense systems, which leads to oxidative stress. In line with ROS, plants also produce a high amount of methylglyoxal (MG), which is an α-oxoaldehyde compound, highly reactive, cytotoxic, and produced via different enzymatic and non-enzymatic reactions. This MG can impair cells or cell components and can even destroy DNA or cause mutation. Under stress conditions, MG concentration in plants can be increased 2- to 6-fold compared with normal conditions depending on the plant species. However, plants have a system developed to detoxify this MG consisting of two major enzymes: glyoxalase I (Gly I) and glyoxalase II (Gly II), and hence known as the glyoxalase system. Recently, a novel glyoxalase enzyme, named glyoxalase III (Gly III), has been detected in plants, providing a shorter pathway for MG detoxification, which is also a signpost in the research of abiotic stress tolerance. Glutathione (GSH) acts as a co-factor for this system. Therefore, this system not only detoxifies MG but also plays a role in maintaining GSH homeostasis and subsequent ROS detoxification. Upregulation of both Gly I and Gly II as well as their overexpression in plant species showed enhanced tolerance to various abiotic stresses including salinity, drought, metal toxicity, and extreme temperature. In the past few decades, a considerable amount of reports have indicated that both antioxidant defense and glyoxalase systems have strong interactions in conferring abiotic stress tolerance in plants through the detoxification of ROS and MG. In this review, we will focus on the mechanisms of these interactions and the coordinated action of

  15. The Future of Organization Design: An Interpretative Synthesis in Three Themes

    Directory of Open Access Journals (Sweden)

    Richard M. Burton

    2013-04-01

    Full Text Available In the inaugural issue of the Journal of Organization Design (Vol. 1, #1, 2012, noted scholars and experienced practitioners presented their views on the future of organization design. The seven wise and provocative statements were subsequently discussed by members of the Organizational Design Community at a conference held at Harvard University on August 3, 2012. I was asked by JOD to monitor the discussion and identify the broad organization design themes that emerged. Although the discussion was wide ranging, three themes were noticeable. The first theme is that there are fundamentals of organization design, and all agreed that design involves creating a cohesive socio-technical system from a number of constituent elements. The second theme is that the boundaries of many newer organizational forms extend beyond that of the single firm, so the scope of organization design needs to expand to include ecosystems, collaborative communities, industries, and other supra-firm architectures. The third theme involves time and change, requiring a shift in focus from how organizations become stable and predictable to how they can become more agile.

  16. Polyamines and abiotic stress in plants: A complex relationship

    Directory of Open Access Journals (Sweden)

    Rakesh eMinocha

    2014-05-01

    Full Text Available The physiological relationship between abiotic stress in plants and polyamines was reported more than 40 years ago. Ever since there has been a debate as to whether increased polyamines protect plants against abiotic stress (e.g. due to their ability to deal with oxidative radicals or cause damage to them (perhaps due to hydrogen peroxide produced by their catabolism. The observation that cellular polyamines are typically elevated in plants under both short-term as well as long-term abiotic stress conditions is consistent with the possibility of their dual effects, i.e. being a protector as well as a perpetrator of stress damage to the cells. The observed increase in tolerance of plants to abiotic stress when their cellular contents are elevated by either exogenous treatment with polyamines or through genetic engineering with genes encoding polyamine biosynthetic enzymes is indicative of a protective role for them. However, through their catabolic production of hydrogen peroxide and acrolein, both strong oxidizers, they can potentially be the cause of cellular harm during stress. In fact, somewhat enigmatic but strong positive relationship between abiotic stress and foliar polyamines has been proposed as a potential biochemical marker of persistent environmental stress in forest trees in which phenotypic symptoms of stress are not yet visible. Such markers may help forewarn forest managers to undertake amelioration strategies before the appearance of visual symptoms of stress and damage at which stage it is often too late for implementing strategies for stress remediation and reversal of damage. This review provides a comprehensive and critical evaluation of the published literature on interactions between abiotic stress and polyamines in plants, and examines the experimental strategies used to understand the functional significance of this relationship with the aim of improving plant productivity, especially under conditions of abiotic stress.

  17. The Promoter of AtUSP Is Co-regulated by Phytohormones and Abiotic Stresses in Arabidopsis thaliana.

    Science.gov (United States)

    Bhuria, Monika; Goel, Parul; Kumar, Sanjay; Singh, Anil K

    2016-01-01

    Universal stress proteins (USPs) are known to be expressed in response to various abiotic stresses in a wide variety of organisms, such as bacteria, archaebacteria, protists, algae, fungi, plants, and animals. However, in plants, biological function of most of the USPs still remains obscure. In the present study, Arabidopsis USP gene ( AtUSP ) showed induction in response to abscisic acid (ABA) and various abiotic stresses viz . heat, dehydration, salt, osmotic, and cold stresses. Additionally, in silico analysis of AtUSP promoter identified several cis -elements responsive to phytohormones and abiotic stresses such as ABRE, ERE, DRE, and HSE, etc. To functionally validate the AtUSP promoter, the 1115 bp region of promoter was characterized under phytohormone and abiotic stress treatments. Deletion analysis of promoter was carried out by cloning the full length promoter (D0) and its three 5' deletion derivatives, D1 (964 bp), D2 (660 bp), and D3 (503 bp) upstream of the β-glucuronidase (GUS) reporter gene, which were then stably transformed in Arabidopsis plants. The AtUSP promoter (D0) showed minimal activity under non-stress conditions which was enhanced in response to phytohormone treatments (ABA and ACC) and abiotic stresses such as dehydration, heat, cold, salt, and osmotic stresses. The seedlings harboring D1 and D2 deletion fragments showed constitutive GUS expression even under control condition with increased activity almost under all the treatments. However, D3 seedlings exhibited complete loss of activity under control condition with induction under ACC treatment, dehydration, heat, oxidative, salt, and osmotic stresses. Thus, present study clearly showed that AtUSP promoter is highly inducible by phytohormones and multiple abiotic stresses and it can be exploited as stress inducible promoter to generate multi-stress tolerant crops with minimal effects on their other important traits.

  18. Aquatic organism passage at road-stream crossings—synthesis and guidelines for effectiveness monitoring

    Science.gov (United States)

    Hoffman, Robert L.; Dunham, Jason B.; Hansen, Bruce P.

    2012-01-01

    Restoration and maintenance of passage for aquatic organisms at road-stream crossings represents a major management priority, involving an investment of hundreds of millions of dollars (for example, U.S. Government Accounting Office, 2001). In recent years, passage at hundreds of crossings has been restored, primarily by replacing barrier road culverts with bridges or stream simulation culverts designed to pass all species and all life stages of aquatic life and simulate natural hydro-geomorphic processes (U.S. Forest Service, 2008). The current situation has motivated two general questions: 1. Are current design standards for stream simulation culverts adequately re-establishing passage for aquatic biota? and 2. How do we monitor and evaluate effectiveness of passage restoration? To address the latter question, a national workshop was held in March 2010, in Portland, Oregon. The workshop included experts on aquatic organism passage from across the nation (see table of participants, APPENDIX) who addressed four classes of methods for monitoring effectiveness of aquatic organism passage—individual movement, occupancy, demography, and genetics. This report has been written, in part, for field biologists who will be undertaking and evaluating the effectiveness of aquatic organism passage restoration projects at road-stream crossings. The report outlines basic methods for evaluating road-stream crossing passage impairment and restoration and discusses under what circumstances and conditions each method will be useful; what questions each method can potentially answer; how to design and implement an evaluation study; and points out the fundamental reality that most evaluation projects will require special funding and partnerships among researchers and resource managers. The report is organized into the following sections, which can be read independently: 1. Historical context: In this section, we provide a brief history of events leading up to the present situation

  19. Hybrid inorganic-organic adsorbents Part 1: Synthesis and characterization of mesoporous zirconium titanate frameworks containing coordinating organic functionalities.

    Science.gov (United States)

    Griffith, Christopher S; De Los Reyes, Massey; Scales, Nicholas; Hanna, John V; Luca, Vittorio

    2010-12-01

    A series of functional hybrid inorganic-organic adsorbent materials have been prepared through postsynthetic grafting of mesoporous zirconium titanate xerogel powders using a range of synthesized and commercial mono-, bis-, and tris-phosphonic acids, many of which have never before been investigated for the preparation of hybrid phases. The hybrid materials have been characterized using thermogravimetric analysis, diffuse reflectance infrared (DRIFT) and 31P MAS NMR spectroscopic techniques and their adsorption properties studied using a 153Gd radiotracer. The highest level of surface functionalization (molecules/nm2) was observed for methylphosphonic acid (∼3 molecules/nm2). The level of functionalization decreased with an increase in the number of potential surface coordinating groups of the phosphonic acids. Spectral decomposition of the DRIFT and 31P MAS NMR spectra showed that each of the phosphonic acid molecules coordinated strongly to the metal oxide surface but that for the 1,1-bis-phosphonic acids and tris-phosphonic acids the coordination was highly variable resulting in a proportion of free or loosely coordinated phosphonic acid groups. Functionalization of a porous mixed metal oxide framework with the tris-methylenephosphonic acid (ATMP-ZrTi-0.33) resulted in a hybrid with the highest affinity for 153Gd3+ in nitric acid solutions across a wide range of acid concentrations. The ATMP-ZrTi-0.33 hybrid material extracted 153Gd3+ with a Kd value of 1×10(4) in 0.01 M HNO3 far exceeding that of the other hybrid phases. The unfunctionalized mesoporous mixed metal oxide had negligible affinity for Gd3+ (KdATMP-ZrTi-0.33 hybrid phase for Gd3+ has been determined to be about 0.005 mmol/g in 0.01 M HNO3. This behavior and that of the other hybrid phases suggests that the surface-bound ATMP ligand functions as a chelating ligand toward 153Gd3+ under these acidic conditions.

  20. Synthesis of organosilicon derivatives of [1]benzothieno[3,2-b][1]-benzothiophene for efficient monolayer Langmuir-Blodgett organic field effect transistors.

    Science.gov (United States)

    Borshchev, O V; Sizov, A S; Agina, E V; Bessonov, A A; Ponomarenko, S A

    2017-01-16

    For the first time, the synthesis of organosilicon derivatives of dialkyl[1]benzothieno[3,2-b][1]-benzothiophene (BTBT) capable of forming a semiconducting monolayer at the water-air interface is reported. Self-assembled monolayer organic field-effect transistors prepared from these materials using the Langmuir-Blodgett technique showed high hole mobilities and excellent air stability.

  1. Continuing Education and Training and the Labour Market. Synthesis Report on a Conference Organized by CEDEFOP (Berlin, West Germany, March 8-9, 1984).

    Science.gov (United States)

    Hege, Adelheid

    This synthesis report summarizes a conference organized to examine the current situation regarding the continuing education and training of adults in the European Community and to formulate proposals for action. Some 60 conference participants examined various research reports, conducted discussions, and presented papers on three major topics:…

  2. An unsymmetrical non-fullerene acceptor: synthesis via direct heteroarylation, self-assembly, and utility as a low energy absorber in organic photovoltaic cells.

    Science.gov (United States)

    Payne, Abby-Jo; Li, Shi; Dayneko, Sergey V; Risko, Chad; Welch, Gregory C

    2017-09-12

    This study reports on the design and synthesis of an unsymmetrical π-conjugated organic molecule composed of perylene diimide, thienyl diketopyrrolopyrrole, and indoloquinoxaline pieced together using direct heteroarylation. This material demonstrates unprecedented response in the thin-film upon post-deposition solvent vapor annealing, resulting in dramatic red-shifts in optical absorption. Such changes were utilized to enhance photocurrent generation in P3HT based organic solar cells.

  3. Contributions of Fe Minerals to Abiotic Dechlorination

    Science.gov (United States)

    Most applications of enhanced in situ bioremediation are based on biological reductive dechlorination. Anaerobic metabolism can also produce reactive minerals that allow for in situ biogeochemical transformation of chlorinated organic contaminants such as PCE, TCE, and cis-DCE. ...

  4. Organic synthesis via irradiation and warming of ice grains in the solar nebula.

    Science.gov (United States)

    Ciesla, Fred J; Sandford, Scott A

    2012-04-27

    Complex organic compounds, including many important to life on Earth, are commonly found in meteoritic and cometary samples, though their origins remain a mystery. We examined whether such molecules could be produced within the solar nebula by tracking the dynamical evolution of ice grains in the nebula and recording the environments to which they were exposed. We found that icy grains originating in the outer disk, where temperatures were less than 30 kelvin, experienced ultraviolet irradiation exposures and thermal warming similar to that which has been shown to produce complex organics in laboratory experiments. These results imply that organic compounds are natural by-products of protoplanetary disk evolution and should be important ingredients in the formation of all planetary systems, including our own.

  5. Designing Multidimensional Policing Strategy And Organization: Towards A Synthesis Of Professional And Community Police Models

    Directory of Open Access Journals (Sweden)

    Suve Priit

    2015-06-01

    Full Text Available In this article we analyse professional police and community policing in view of professionalism, strategy and structures. We aim to find ways for synthesizing these models that are usually seen as incompatible. Unlike many earlier studies of police organizations or strategies, we view strategies in the organization at the corporate, functional and operational levels, and argue that by combining them with functional and divisional principles of structuring, it is possible to place professional strategy at the core of policing, while using the community policing strategy mainly as a component part of the strategy in the framework of divisional organization. This way it is possible to avoid the risk of alienating police from the community and to ensure the successful implementation of corporate strategy through providing professional police units that perform the narrow functions, with quick and adequate information from the community.

  6. Organic Synthesis via Irradiation and Warming of Ice Grains in the Solar Nebula

    Science.gov (United States)

    Ciesla, Fred J.; Sanford, Scott A.

    2012-01-01

    Complex organic compounds, including many important to life on Earth, are commonly found in meteoritic and cometary samples, though their origins remain a mystery. We examined whether such molecules could be produced within the solar nebula by tracking the dynamical evolution of ice grains in the nebula and recording the environments they were exposed to. We found that icy grains originating in the outer disk, where temperatures were less than 30 K, experienced UV irradiation exposures and thermal warming similar to that which has been shown to produce complex organics in laboratory experiments. These results imply that organic compounds are natural byproducts of protoplanetary disk evolution and should be important ingredients in the formation of all planetary systems, including our own.

  7. Organic-inorganic hybrid polymer electrolytes based on polyether diamine, alkoxysilane, and trichlorotriazine: Synthesis, characterization, and electrochemical applications

    Science.gov (United States)

    Saikia, Diganta; Wu, Cheng-Gang; Fang, Jason; Tsai, Li-Duan; Kao, Hsien-Ming

    2014-12-01

    A new type of highly conductive organic-inorganic hybrid polymer electrolytes has been synthesized by the reaction of poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether), 2,4,6-trichloro-1,3,5-triazine and alkoxysilane precursor 3-(glycidyloxypropyl)trimethoxysilane, followed by doping of LiClO4. The 13C and 29Si solid-sate NMR results confirm the successful synthesis of the organic-inorganic hybrid structure. The solid hybrid electrolyte thus obtained exhibits a maximum ionic conductivity of 1.6 × 10-4 S cm-1 at 30 °C, which is the highest among the organic-inorganic hybrid electrolytes. The hybrid electrolytes are electrochemically stable up to 4.2 V. The prototype electrochromic device with such a solid hybrid electrolyte demonstrates a good coloration efficiency value of 183 cm2 C-1 with a cycle life over 200 cycles. For the lithium-ion battery test, the salt free solid hybrid membrane is swelled with a LiPF6-containing electrolyte solution to reach an acceptable ionic conductivity value of 6.5 × 10-3 S cm-1 at 30 °C. The battery cell carries an initial discharge capacity of 100 mAh g-1 at 0.2C-rate and a coulombic efficiency of about 95% up to 30 cycles without the sign of cell failure. The present organic-inorganic hybrid electrolytes hold promise for applications in electrochromic devices and lithium ion batteries.

  8. Before the Ring: synthesis of linear organic molecules in astrophysical ices by low energy electron impact

    Science.gov (United States)

    Huels, Michael A.; Bass Andrew, D.; Mirsaleh-Kohan, Nasrin; Sanche, Leon

    The question of the origin for the building blocks of life, either synthesized here on earth, or in space [1], has been the subject of much debate, experimental investigation, or astronomical observation, much of it stimulated by the early experiments of Miller [2], and subsequent space radiation related variations thereof [3-5]. And while the precise details of the formation of even the simplest biomolecules that make up life on earth still remain shrouded inmystery, one of the notions that persist throughout the debate is that the building blocks of life, such as amino-acids, or even the cyclic components of RNA and DNA, or other cyclic hydrocarbons (e.g. PHAs), where synthesized via radiolysis [6] either in the earths proto-atmosphere, its early oceans, or in the near interstellar space surrounding the early earth. Here we provide experimental evidence for the hypothesis that interactions of low energy secondary electrons and ions, formed during the radiolysis of matter, with atoms and molecules in the medium, may have played, and may still play an important role in the chemical transformation of astrophysical or planetary surface ices [7], where they lead to the synthesis of more complex chemical species from less complex, naturally occurring components. We report the synthesis and desorption of new chemical species from simple molecular surface ices, containing CH4 / CD4 , C2 D2 , O2 , CO, CO2 , or N2 in various combination mixtures, irradiated by low energy (CO+ (n = 1-3), among others. The formation of all these linear, pre-biotic molecular species, produced here by electron initiated cation-reactions in simple molecular films, suggests that similar mechanisms likely precede the synthesis of life's most basic cyclic molecular components in planetary, or astrophysical surface ices that are continuously subjected to the types of space radiations (UV, X-or -ray, or heavy ions) that can generate such low energy secondary electrons. [Funded by NSERC and Canadian

  9. Total observed organic carbon (TOOC in the atmosphere: a synthesis of North American observations

    Directory of Open Access Journals (Sweden)

    C. L. Heald

    2008-04-01

    Full Text Available Measurements of organic carbon compounds in both the gas and particle phases made upwind, over and downwind of North America are synthesized to examine the total observed organic carbon (TOOC in the atmosphere over this region. These include measurements made aboard the NOAA WP-3 and BAe-146 aircraft, the NOAA research vessel Ronald H. Brown, and at the Thompson Farm and Chebogue Point surface sites during the summer 2004 ICARTT campaign. Both winter and summer 2002 measurements during the Pittsburgh Air Quality Study are also included. Lastly, the spring 2002 observations at Trinidad Head, CA, surface measurements made in March 2006 in Mexico City and coincidentally aboard the C-130 aircraft during the MILAGRO campaign and later during the IMPEX campaign off the northwestern United States are incorporated. Concentrations of TOOC in these datasets span more than two orders of magnitude. The daytime mean TOOC ranges from 4.0 to 456 μgC m−3 from the cleanest site (Trinidad Head to the most polluted (Mexico City. Organic aerosol makes up 3–17% of this mean TOOC, with highest fractions reported over the northeastern United States, where organic aerosol can comprise up to 50% of TOOC. Carbon monoxide concentrations explain 46 to 86% of the variability in TOOC, with highest TOOC/CO slopes in regions with fresh anthropogenic influence, where we also expect the highest degree of mass closure for TOOC. Correlation with isoprene, formaldehyde, methyl vinyl ketone and methacrolein also indicates that biogenic activity contributes substantially to the variability of TOOC, yet these tracers of biogenic oxidation sources do not explain the variability in organic aerosol observed over North America. We highlight the critical need to develop measurement techniques to routinely detect total gas phase VOCs, and to deploy comprehensive suites of TOOC instruments in diverse environments to quantify the ambient evolution of organic carbon from source

  10. Ferrocenyl and organic novobiocin derivatives: Synthesis and their in vitro biological activity.

    Science.gov (United States)

    Mbaba, Mziyanda; Mabhula, Amanda N; Boel, Natasha; Edkins, Adrienne L; Isaacs, Michelle; Hoppe, Heinrich C; Khanye, Setshaba D

    2017-07-01

    A focused series of novobiocin derivatives containing a ferrocene unit together with their corresponding organic novobiocin analogues have been synthesized in modest to good yields. These compounds were screened for biological activity against a chloroquine-sensitive strain of Plasmodium falciparum (3D7) and human breast cancer cell line (HCC38). With the exception of compounds 5c and 5d, the general trend observed is that incorporation of the ferrocene moiety into novobiocin scaffold resulted in compounds 6a-d/6f showing enhanced activity compared to organic analogues 5a-b and 5e-f. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Enzymatic Synthesis of Esculin Ester in Ionic Liquids Buffered with Organic Solvents

    DEFF Research Database (Denmark)

    Hu, Yifan; Guo, Zheng; Lue, Bena-Marie

    2009-01-01

    The enzymatic esterification of esculin catalyzed by Candida antarctica lipase B (Novozym 435) was carried out in ionic liquid (IL)-organic solvent mixed systems in comparison with individual systems. The reaction behaviors in IL-organic solvents were systemically evaluated using acetone as a model...... in IL-acetone mixtures made it possible to improve the solubility of esculin while the effects of ILs on lipase activity were minimized. Following the benignity of ILs to lipase activity, the anions of ILs were ranked in the order as [Tf2N](-) > [PF6](-) > [BF4](-) > [CF3SO3](-) > [C4F9SO3](-) > [TAF...

  12. Determination of Innovation Capability of Organizations: Qualitative Meta Synthesis and Delphi Method

    DEFF Research Database (Denmark)

    Momeni, Mostafa; Nielsen, Susanne Balslev; Kafash, Mahdi Haghighi

    2015-01-01

    . The innovation capability is associated with other organizational capabilities. So, many organizations have focused on the need to identify innovation capabilities and resources or strengths in relation to external opportunities and threats according to inside-out view because innovation capability has...... capability in the organizations and this paper includes an expert based validation in three rounds of the Delphi method. This research proposed a direct relationship between Innovation Capability and three main capabilities that is called Structural Capability, Personnel Capability and Operational Capability...

  13. Synthesis, characterization and crystal structures of new organic compounds containing cyanoacrylic acid

    Czech Academy of Sciences Publication Activity Database

    Khalaji, A.D.; Mogheiseh, M.; Eigner, Václav; Dušek, Michal; Chow, T.J.; Maddahi, E.

    2015-01-01

    Roč. 1098, Oct (2015), s. 318-323 ISSN 0022-2860 R&D Projects: GA ČR(CZ) GA14-03276S Institutional support: RVO:68378271 Keywords : organic compounds * cyanoacrylic acid * single-crystal structure analysis * dye-sensitized solar cells * density functional theory Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.780, year: 2015

  14. Lipase-supported metal-organic framework bioreactor catalyzes warfarin synthesis.

    Science.gov (United States)

    Liu, Wan-Ling; Yang, Ni-Shin; Chen, Ya-Ting; Lirio, Stephen; Wu, Cheng-You; Lin, Chia-Her; Huang, Hsi-Ya

    2015-01-02

    A green and sustainable strategy synthesizes clinical medicine warfarin anticoagulant by using lipase-supported metal-organic framework (MOF) bioreactors (see scheme). These findings may be beneficial for future studies in the industrial production of chemical, pharmaceutical, and agrochemical precursors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

    Directory of Open Access Journals (Sweden)

    Sebastian Krüger

    2014-01-01

    Full Text Available This review summarizes the application of the divinylcyclopropane–cycloheptadiene rearrangement in synthetic organic chemistry. A brief overview of the new mechanistic insights concerning the title reaction is provided as well as a condensed account on the biological relevance of the topic. Heteroatom variants of this rearrangement are covered briefly.

  16. Aerosol-assisted synthesis of mesoporous organosilica microspheres with controlled organic contents

    Directory of Open Access Journals (Sweden)

    Yusuke Yamauchi, Norihiro Suzuki, Prashant Gupta, Keisuke Sato, Naoki Fukata, Miwa Murakami, Tadashi Shimizu, Satoru Inoue and Tatsuo Kimura

    2009-01-01

    Full Text Available Periodic mesoporous organosilica (PMO spherical particles with different organic contents were synthesized in one pot by reacting 1,2-bis(triethoxysilylethane (BTSE with tetraethylorthosilicate (TEOS using a spray-drying technique. The scanning electron microscopy observation of spray-dried products clearly showed the formation of spherical particles. The 29Si magic angle spinning nuclear magnetic resonance data revealed that the organic contents due to ethane fragments embedded in the frameworks were controllable and consistent with the BTSE/TEOS molar ratios of precursor solutions. Transmission electron microscopy, small-angle x-ray scattering, and N2 adsorption data of PMO with controlled organic contents indicated that the ethane fragments were embedded in the frameworks with the formation of ordered mesostructures. PMO with a high organic content (BTSE/TEOS=0.50 only showed a hydrophobic property. According to the same procedure, benzene groups were also integrated to a similar degree in the frameworks by using 1,4-bis(triethoxysilylbenzene.

  17. Novel approaches for using dehydrogenases and ene-reductases for organic synthesis

    NARCIS (Netherlands)

    Gargiulo, S.

    2015-01-01

    Oxidation of alcohols is a reaction of major interest for organic chemistry. However, the most common chemical routes developed so far involve the use of toxic or hazardous reagents or catalysts that often lack good chemoselectivity. In this respect, alcohol dehydrogenases (ADHs) represent a very

  18. Independent Synthesis Projects in the Organic Chemistry Teaching Laboratories: Bridging the Gap between Student and Researcher

    Science.gov (United States)

    Keller, Valerie A.; Kendall, Beatrice Lin

    2017-01-01

    Science educators strive to teach students how to be well-rounded scientists with the ability to problem solve, anticipate errors, and adapt to unexpected roadblocks. Traditional organic chemistry experiments seldom teach these skills, no matter how novel or contemporary the subject material. This paper reports on the success of a quarter-long…

  19. Synthesis and Characterization of Calixarene Tetraethers: An Exercise in Supramolecular Chemistry for the Undergraduate Organic Laboratory

    Science.gov (United States)

    Debbert, Stefan L.; Hoh, Bradley D.; Dulak, David J.

    2016-01-01

    In this experiment for an introductory undergraduate organic chemistry lab, students tetraalkylate tertbutylcalix[4]arene, a bowl-shaped macrocyclic oligophenol, and examine the supramolecular chemistry of the tetraether product by proton nuclear magnetic resonance (NMR) spectroscopy. Complexation with a sodium ion reduces the conformational…

  20. Enhancement and assessment of students’ systems thinking skills by application of systemic synthesis questions in the organic chemistry course

    Directory of Open Access Journals (Sweden)

    Hrin Tamara N.

    2016-01-01

    Full Text Available Many studies in the field of science education have emphasized the fact that systems thinking is a very important higher-order thinking skill which should be fostered during classes. However, more attention has been dedicated to the different ways of systems thinking skills assessment, and less to their enhancement. Taking this into consideration, the goal of our study was not only to validate secondary school students’ systems thinking skills, but also to help students in the complex process of their development. With this goal, new instructional and assessment tools - systemic synthesis questions [SSynQs], were constructed, and an experiment with one experimental (E and one control (C group was conducted during organic chemistry classes. Namely, the instructional teaching/learning method for both E and C groups was the same in processing the new contents, but different on classes for the revision of the selected organic chemistry contents. The results showed that students exposed to the new instructional method (E group achieved higher performance scores on three different types of systems thinking than students from the C group, who were taught by the traditional method. The greatest difference between the groups was found in the most complex dimension of systems thinking construct - in the II level of procedural systems thinking. Along with this dimension, structural systems thinking and I level of procedural systems thinking were also observed. [Projekat Ministarstva nauke Republike Srbije, br. 179010

  1. Synthesis of carbon quantum dots and zinc oxide nanosheets by pyrolysis of novel metal–organic framework compounds

    International Nuclear Information System (INIS)

    Ma, Qiliang; Zhang, Zhaochun; Yu, Zhenwei

    2015-01-01

    Highlights: • Thermodynamic and kinetic analysis of porous MOFs. • One step synthesis of CQDs and ZnO nanosheets. • The coexistence of CQDs and ZnO nanosheets show strong ultraviolet emission. - Abstract: Here, the carbon quantum dots and zinc oxide nanosheets with novel superstructures are successfully synthesized simultaneously from a hydrothermal preparation and thermal decomposition of a porous precursor of metal–organic frameworks. Porous metal–organic frameworks are prepared by the hydrothermal process by using zinc nitrate hexahydrate, 4,4′-oxybisbenzoic acid and 4,4′-bipyridine as the starting materials. Fluorescence spectrophotometer, X-ray powder diffraction, transmission electron microscopy and high-resolution transmission electron microscopy were used to characterize the structure and property. The results show the coexistence of carbon quantum dots and zinc oxide nanosheets. The carbon quantum dots size is about 4 nm. Particularly, zinc oxide nanosheets show a new triangular sheet structure that has almost the same size. Strong ultraviolet emission of this coexistence system should be useful in developing visible light-emitting and nanophotonic devices

  2. Self-Templated Stepwise Synthesis of Monodispersed Nanoscale Metalated Covalent Organic Polymers for In Vivo Bioimaging and Photothermal Therapy.

    Science.gov (United States)

    Shi, Yanshu; Deng, Xiaoran; Bao, Shouxin; Liu, Bei; Liu, Bin; Ma, Ping'an; Cheng, Ziyong; Pang, Maolin; Lin, Jun

    2017-09-05

    Size- and shape-controlled growth of nanoscale microporous organic polymers (MOPs) is a big challenge scientists are confronted with; meanwhile, rendering these materials for in vivo biomedical applications is still scarce. In this study, a monodispersed nanometalated covalent organic polymer (MCOP, M=Fe, Gd) with sizes around 120 nm was prepared by a self-templated two-step solution-phase synthesis method. The metal ions (Fe 3+ , Gd 3+ ) played important roles in generating a small particle size and in the functionalization of the products during the reaction with p-phenylenediamine (Pa). The resultant Fe-Pa complex was used as a template for the subsequent formation of MCOP following the Schiff base reaction with 1,3,5-triformylphloroglucinol (Tp). A high tumor suppression efficiency for this Pa-based COP is reported for the first time. This study demonstrates the potential use of MCOP as a photothermal agent for photothermal therapy (PTT) and also provides an alternative route to fabricate nano-sized MCOPs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Synthesis of carbon quantum dots and zinc oxide nanosheets by pyrolysis of novel metal–organic framework compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qiliang; Zhang, Zhaochun, E-mail: zhangzhaochun@shu.edu.cn; Yu, Zhenwei

    2015-09-05

    Highlights: • Thermodynamic and kinetic analysis of porous MOFs. • One step synthesis of CQDs and ZnO nanosheets. • The coexistence of CQDs and ZnO nanosheets show strong ultraviolet emission. - Abstract: Here, the carbon quantum dots and zinc oxide nanosheets with novel superstructures are successfully synthesized simultaneously from a hydrothermal preparation and thermal decomposition of a porous precursor of metal–organic frameworks. Porous metal–organic frameworks are prepared by the hydrothermal process by using zinc nitrate hexahydrate, 4,4′-oxybisbenzoic acid and 4,4′-bipyridine as the starting materials. Fluorescence spectrophotometer, X-ray powder diffraction, transmission electron microscopy and high-resolution transmission electron microscopy were used to characterize the structure and property. The results show the coexistence of carbon quantum dots and zinc oxide nanosheets. The carbon quantum dots size is about 4 nm. Particularly, zinc oxide nanosheets show a new triangular sheet structure that has almost the same size. Strong ultraviolet emission of this coexistence system should be useful in developing visible light-emitting and nanophotonic devices.

  4. Synthesis of Conjugated Small Molecules and Polymers by a Palladium Catalyzed Cyclopentannulation Strategy: Towards New Organic Semiconductors

    Science.gov (United States)

    Bheemireddy, Sambasiva Reddy

    The utility of conjugated small molecules and polymers as organic semiconductors have seen a tremendous growth in research and development in academia as well as industry because of their processability and flexibility advantages in comparison to inorganic semiconductors. The extensive research over the years has produced a large number of p-type (hole conducting) and n-type (electron conducting) semiconductors that can be used to construct organic electronic devices. Of these materials, p-type semiconductors are more established and extensively studied because of the ease of preparation as well as their better general stability in comparison to n-type materials. Despite recent research into the development of n-type materials, fullerene (C60 and C 70) and its derivatives are still the predominant materials used as electron acceptors for OPV applications. By taking advantage of the electron accepting behavior of cyclopenta[hi]aceanthrylene fragment of C70, we have designed and synthesized new materials based on cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs). By using a newly developed palladium catalyzed cyclopentannulation methodology, 1,2,6,7- tetraarylcyclopenta[hi]aceanthrylenes were prepared by treating diarylethynylenes with 9,10-dibromoanthracene. Scholl cyclodehydrogenation was used to close the externally fused aryl groups to provide access to contorted 2,7,13,18- tetraalkoxytetrabenzo[f,h,r,t]rubicenes. The contortion provides access to more soluble materials than their planar counterparts but still ii allows significant pi-pi stacking between molecules. Using a modified palladium catalyzed cyclopentannulation polymerization followed by a cyclodehydrogenation reaction, a nonconventional synthesis of CP-PAH embedded ladder polymers was also achieved. These ladder polymers possess broad UV-Vis absorptions and narrow optical gaps of 1.17-1.29 eV. The synthesis of new donor-acceptor copolymers incorporating electron accepting 1,2,6,7- tetra(4

  5. The Role of Silicon under Biotic and Abiotic Stress Conditions

    Directory of Open Access Journals (Sweden)

    İlkay YAVAŞ

    2017-06-01

    Full Text Available Biotic and abiotic stress factors can adversely affect the agricultural productivity leading to physiological and biochemical damage to crops. Therefore, the most effective way is to increase the resistance to stresses. Silicon plays a ro le in reducing the effects of abiotic and biotic stresses (drought, salt stress, disease and insect stress etc. on plants. Silicon is accumulated in the cell walls and intercellular spaces and thus it has beneficial effects on disease infestations in especially small grains. The application of silicon may reduce the effects of environmental stresses on plants while making effective use of plant nutrients such as nitrogen and phosphorous. Also, silicon may reduce the toxic effects of heavy metals in soil. I t may protect the foliage and increase light uptake and reduce respiration. Therefore, in this review, we discussed the effects of silicon on abiotic and biotic stresses in especially field crops.

  6. Current perspectives in proteomic analysis of abiotic stress in Grapevines

    Directory of Open Access Journals (Sweden)

    Iniga Seraphina George

    2014-12-01

    Full Text Available Grapes are an important crop plant which forms the basis of a globally important industry. Grape and wine production is particularly vulnerable to environmental and climatic fluctuations, which makes it essential for us to develop a greater understanding of the molecular level responses of grape plants to various abiotic stresses. The completion of the initial grape genome sequence in 2007 has led to a significant increase in research on grapes using proteomics approaches. In this article, we discuss some of the current research on abiotic stress in grapevines, in the context of abiotic stress research in other plant species. We also highlight some of the current limitations in grapevine proteomics and identify areas with promising scope for potential future research.

  7. Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Castillo, Alfredo Santiago [Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France); Université européenne de Bretagne (France); Guihéneuf, Solène, E-mail: solene.guiheneuf@wanadoo.fr [Université européenne de Bretagne, Université de Rennes 1, Sciences Chimiques de Rennes, UMR, CNRS 6226, Groupe Ingénierie Chimique & Molécules Pour le Vivant (ICMV), Bât. 10A, Campus de Beaulieu, Avenue du Général Leclerc, CS 74205, 35042 Rennes cedex (France); Le Guével, Rémy [Plate-forme ImPACcell Structure Fédérative de Recherche BIOSIT Université de Rennes 1, Bat. 8, Campus de Villejean, 2 Avenue du Pr. Leon Bernard, CS 34317, 35043 Rennes Cedex (France); Biard, Pierre-François [Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France); Université européenne de Bretagne (France); and others

    2016-04-15

    Highlights: • Description of a VOC depollution system suitable with industrial processes, TPPB. • Novel association of TPPB and hydrophobic ionic liquids. • Synthesis of several hydrophobic ionic liquids designed to fit desired properties. • Toxicity evaluation of these ILs towards cells, animals and bacteria. - Abstract: Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF{sub 6}{sup −}, NTf{sub 2}{sup −} and NfO{sup −}. Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD{sub 28} of aqueous samples (compound concentration,1 mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation.

  8. Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor

    International Nuclear Information System (INIS)

    Rodriguez Castillo, Alfredo Santiago; Guihéneuf, Solène; Le Guével, Rémy; Biard, Pierre-François

    2016-01-01

    Highlights: • Description of a VOC depollution system suitable with industrial processes, TPPB. • Novel association of TPPB and hydrophobic ionic liquids. • Synthesis of several hydrophobic ionic liquids designed to fit desired properties. • Toxicity evaluation of these ILs towards cells, animals and bacteria. - Abstract: Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF_6"−, NTf_2"− and NfO"−. Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD_2_8 of aqueous samples (compound concentration,1 mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation.

  9. Synthesis of novel cellulose- based antibacterial composites of Ag nanoparticles@ metal-organic frameworks@ carboxymethylated fibers.

    Science.gov (United States)

    Duan, Chao; Meng, Jingru; Wang, Xinqi; Meng, Xin; Sun, Xiaole; Xu, Yongjian; Zhao, Wei; Ni, Yonghao

    2018-08-01

    A novel cellulose-based antibacterial material, namely silver nanoparticles@ metal-organic frameworks@ carboxymethylated fibers composites (Ag NPs@ HKUST-1@ CFs), was synthesized. The results showed that the metal-organic frameworks (HKUST-1) were uniformly anchored on the fiber's surfaces by virtue of complexation between copper ions in HKUST-1 and carboxyl groups on the carboxymethylated fibers (CFs). The silver nanoparticles (Ag NPs) were immobilized and well-dispersed into the pores and/or onto the surfaces of HKUST-1 via in situ microwave reduction, resulting in the formation of novel Ag NPs@ HKUST-1@ CFs composites. The antibacterial assays showed that the as-prepared composites exhibited a much higher antibacterial activity than Ag NPs@ CFs or HKUST-1@ CFs samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Synthesis and adsorption behaviour of some organic and inorganic sorbents for some hazardous toxic elements

    International Nuclear Information System (INIS)

    El-Naggar, I.M.; Abou-Mesalam, M.M.; Abdel-Hamid, M.M.; Shady, S.A.; Aly, H.F.

    2000-01-01

    Poly (acrylamide-acrylic acid ) -zirconium phosphate p(AM-AA) -Zr p is a new organic resin and can be synthesized by gamma radiation induced polymerization of acrylic acid (AA) in the presence of poly acrylamide (PAM) using a template polymerization technique in the presence of zirconium oxychloride and then soaking in phosphoric acid. The obtained polymer shows an excellent thermal and chemical stabilities, high capacities measurements in addition to high selectivity behaviour to some hazardous heavy metals. In a comparative study for the previous organic resin, P(AM-AA)-Zr P with cerium(IV) antimonate (Ce Sb) and titanium (IV) antimonate (Ti Sb) as inorganic ion exchangers we can concluded that both of Ce Sb and Ti Sb have a greater selectivities to the hazardous heavy metals as compared with p(AM-AA) Zr P whereas the later has a higher capacity than Ce Sb and Ti Sb

  11. Synthesis, characterization and nano-structuration of poly-thiophene derivatives for organic photovoltaic solar cells

    International Nuclear Information System (INIS)

    Berson, S.

    2007-10-01

    This work is devoted to the synthesis of poly-thiophene derivatives with low bandgap and preserving high oxidation potential. Disubstituted thiophenes and 'Donor-Acceptor' bi-thiophenes were synthesized and then polymerized. The side chains of these polymers, donor or acceptor, were modified in order to tune the properties of material as well from the optical point of view as electrochemical. These polymers were also tested in blend with PCBM in bulk-heterojunction photovoltaic cells. Voc delivered by the devices showed a linear dependence according to the potential of oxidation of the polymers. Copolymers containing cyano-thiophene and alkyl- or alkoxy-thiophene showed values of 0.8 V. However, in spite of power conversion efficiency of 1 %, these performances remain lower than the one obtained with the P3HT. Optimizations in terms of morphology are certainly necessary. Indeed, the morphology of the active layer plays a key role in obtaining high power conversion efficiency. An original technique of nano-structuration of the polymer on a nano-metric scale was developed during this work, leading to the development of fibrillar P3HT. These nano-structures, presenting an important degree of order, are formed spontaneously in solution. Their rate compared to amorphous material is perfectly controllable and adjustable in solution and in solid state. Measurements of mobilities show a strong improvement of the transport of load within these fibrillar layers compared to a traditional film of P3HT obtained without annealing. Power conversion efficiencies of 3.6% on glass and 3.3 % on plastic were reached without annealing. (author)

  12. Synthesis, characterization and nano-structuration of poly-thiophene derivatives for organic photovoltaic solar cells

    International Nuclear Information System (INIS)

    Berson, S.

    2007-10-01

    This work is devoted to the synthesis of poly-thiophene derivatives with low bandgap and preserving high oxidation potential. Di-substituted thiophenes and 'Donor-Acceptor' bi-thiophenes were synthesized and then polymerized. The side chains of these polymers, donor or acceptor, were modified in order to tune the properties of material as well from the optical point of view as electrochemical. These polymers were also tested in blend with PCBM in bulk-heterojunction photovoltaic cells. Voc delivered by the devices showed a linear dependence according to the potential of oxidation of the polymers. Copolymers containing cyano-thiophene and alkyl- or alkoxy-thiophene showed values of 0.8 V. However, in spite of power conversion efficiency of 1 %, these performances remain lower than the one obtained with the P3HT. Optimizations in terms of morphology are certainly necessary. Indeed, the morphology of the active layer plays a key role in obtaining high power conversion efficiency. An original technique of nano-structuration of the polymer on a nano-metric scale was developed during this work, leading to the development of fibrillary P3HT. These nano-structures, presenting an important degree of order, are formed spontaneously in solution. Their rate compared to amorphous material is perfectly controllable and adjustable in solution and in solid state. Measurements of mobilities show a strong improvement of the transport of load within these fibrillary layers compared to a traditional film of P3HT obtained without annealing. Power conversion efficiencies of 3.6 % on glass and 3.3 % on plastic were reached without annealing. (author)

  13. Synthesis and characterization of the removal of organic pollutants in effluents.

    Science.gov (United States)

    Bakayoko, Moussa; Kalakodio, Loissi; Kalagodio, Adiara; Abo, Bodjui Olivier; Muhoza, Jean Pierre; Ismaila, El Moctar

    2018-04-25

    The use of a large number of organic pollutants results in the accumulation of effluents at the places of production and the environment. These substances are, therefore, dangerous for living organisms and can cause heavy environmental damage. Hence, to cure these problems certain methods were used for the elimination of organic effluents. Indeed, the methods of elimination through magnetic adsorption and/or separation prove to be effective in the treatment of certain wastes, but the effectiveness of each one of these methods depends on several characteristics and also present limitations according to the pollutants they adsorb. This review examines on the one hand the capacity of certain elements of these methods in the elimination of certain pollutants and on the other hand the advantages and limits of these methods. Elements like biochars, biosorbents and composite materials are used due to their very strong porosity which makes it possible for them to develop an important contact surface with the external medium, at low costs, and the possibility of producing them from renewable sources. The latter still run up however against the problems of formation of mud and regeneration. Depollution by magnetic separation is also used due to its capacity to mitigate the disadvantages of certain methods which generally lead to the formation of mud and overcoming also the difficulties like obtaining an active material and at the same time being able to fix the pollutants present in the effluents to treat and sensitize them to external magnetic fields.

  14. Nanoarmored Enzymes for Organic Enzymology: Synthesis and Characterization of Poly(2-Alkyloxazoline)-Enzyme Conjugates.

    Science.gov (United States)

    Leurs, Melanie; Tiller, Joerg C

    2017-01-01

    The properties of enzymes can be altered significantly by modification with polymers. Numerous different methods are known to obtain such polymer-enzyme conjugates (PECs). However, there is no universal method to render enzymes into PECs that are fully soluble in organic solvents. Here, we present a method, which achieves such high degree of modification of proteins that the majority of modified enzymes will be soluble in organic solvents. This is achieved by preparing poly(2-alkyloxazoline)s (POx) with an NH 2 end group and coupling this functional polymer via pyromellitic acid dianhydride onto the amino groups of the respective protein. The resulting PECs are capable of serving as surfactants for unmodified proteins, rendering the whole mixture organosoluble. Depending on the nature of the POx and the molecular weight and the nature of the enzyme, the PECs are soluble in chloroform or even toluene. Another advantage of this method is that the poly(2-alkyloxazoline) can be activated with the coupling agent and used for the enzyme conjugation without further purification. The POx-enzyme conjugates generated by this modification strategy show modulated catalytic activity in both, aqueous and organic, systems. © 2017 Elsevier Inc. All rights reserved.

  15. Templated synthesis, postsynthetic metal exchange, and properties of a porphyrin-encapsulating metal-organic material

    KAUST Repository

    Zhang, ZhenJie

    2012-01-18

    Reaction of biphenyl-3,4′,5-tricarboxylate (H 3BPT) and CdCl 2 in the presence of meso-tetra(N-methyl-4-pyridyl)porphine tetratosylate (TMPyP) afforded porph@MOM-10, a microporous metal-organic material containing CdTMPyP cations encapsulated in an anionic Cd(II) carboxylate framework, [Cd 6(BPT) 4Cl 4(H 2O) 4]. Porph@MOM-10 is a versatile platform that undergoes exchange to serve as the parent of a series of porph@MOMs that exhibit permanent porosity and heterogeneous catalytic activity. © 2011 American Chemical Society.

  16. SYNTHESIS AND CHARACTERIZATION OF CdSe COLLOIDAL QUANTUM DOTS IN ORGANIC SOLVENT

    Directory of Open Access Journals (Sweden)

    Ion Geru

    2014-06-01

    Full Text Available In this paper we present experimental results on preparation and characterization of colloidal CdSe quantum dots in organic solvent. CdSe QDs were synthesized following a modified literature method. CdSe QDs were isolated by adding acetone to the cooled solution followed by centrifugation. CdSe QDs have been characterized by UV-Vis absorption and photoluminescent (PL spectroscopy. The average CdSe particles size estimated from the UV-Vis absorption spectra was found to be in the range 2.28-2.92 nm which is in good agreement with PL measurements.

  17. Self-organized synthesis of silver dendritic nanostructures via an electroless metal deposition method

    Science.gov (United States)

    Qiu, T.; Wu, X. L.; Mei, Y. F.; Chu, P. K.; Siu, G. G.

    2005-09-01

    Unique silver dendritic nanostructures, with stems, branches, and leaves, were synthesized with self-organization via a simple electroless metal deposition method in a conventional autoclave containing aqueous HF and AgNO3 solution. Their growth mechanisms are discussed in detail on the basis of a self-assembled localized microscopic electrochemical cell model. A process of diffusion-limited aggregation is suggested for the formation of the silver dendritic nanostructures. This nanostructured material is of great potential to be building blocks for assembling mini-functional devices of the next generation.

  18. Differential contributions to the transcriptome of duplicated genes in response to abiotic stresses in natural and synthetic polyploids.

    Science.gov (United States)

    Dong, Shaowei; Adams, Keith L

    2011-06-01

    Polyploidy has occurred throughout plant evolution and can result in considerable changes to gene expression when it takes place and over evolutionary time. Little is known about the effects of abiotic stress conditions on duplicate gene expression patterns in polyploid plants. We examined the expression patterns of 60 duplicated genes in leaves, roots and cotyledons of allotetraploid Gossypium hirsutum in response to five abiotic stress treatments (heat, cold, drought, high salt and water submersion) using single-strand conformation polymorphism assays, and 20 genes in a synthetic allotetraploid. Over 70% of the genes showed stress-induced changes in the relative expression levels of the duplicates under one or more stress treatments with frequent variability among treatments. Twelve pairs showed opposite changes in expression levels in response to different abiotic stress treatments. Stress-induced expression changes occurred in the synthetic allopolyploid, but there was little correspondence in patterns between the natural and synthetic polyploids. Our results indicate that abiotic stress conditions can have considerable effects on duplicate gene expression in a polyploid, with the effects varying by gene, stress and organ type. Differential expression in response to environmental stresses may be a factor in the preservation of some duplicated genes in polyploids. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  19. Correlation between macrobenthic structure (biotic) and water-sediment characteristics (abiotic) adjacent aquaculture areas at Tembelas Island, indonesia

    Science.gov (United States)

    Sharani, Jeanny; Hidayat, Jafron W.; Putro, Sapto P.

    2018-05-01

    Macrobenthic community play important role in sedimentary habitats as a part of food chain. Their structure may be influenced by environmental characteristic spatially and temporally. The purpose of this study is to access the correlation between macrobenthic structure (biotic) and water-sediment characteristics (abiotic) adjacent aquaculture areas at Tembelas Island, Indonesia. Water and sediments samples were taken twice, where the first and second sampling time were taken in June and October 2016, respectively. Samples were taken in the area of fish farming at coastal area of policulture/IMTA (as Location I), site of 1 km away from fish farming area as a reference site (as Location II), and monoculture sites (as Location III), with three stations for each location. Data of abiotic parameters included the composition of sediment substrate and DO, pH, salinity, temperature, and. Sediment samples were taken using Ekman grab. The organisms were 1 mm -size sieved and fixed using 10% formalin for further analysis, i.e. sorting, preserving, enumerating, identifying, and grouping. The relationship between biotics (macrobentos) and abiotics (physical-chemical factors) was assessed using a non-parametric multivariate procedure (BIOENV). This study found 61 species consisting of 46 families and 5 classes of macrobenthos. The most common classes were member of Mollusca and Polychaeta. Total nitrogen, silt, and clay were the abiotic factors most influencing macrobenthic structure (BIO-ENV; r = 0.46; R2 = 21.16%).

  20. Organic compounds containing methoxy and cyanoacrylic acid: Synthesis, characterization, crystal structures, and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Khalaji, A. D., E-mail: alidkhalaji@yahoo.com [Golestan University, Department of Chemistry, Faculty of Science (Iran, Islamic Republic of); Maddahi, E. [Iran University of Science & Technology, Ms.C Educated, Department of Chemistry (Iran, Islamic Republic of); Dusek, M.; Fejfarova, K. [Institute of Physics of the ASCR, v.v.i. (Czech Republic); Chow, T. J. [Academia Sinica, Institute of Chemistry (China)

    2015-12-15

    Metal-free organic compounds 24-SC ((E)-2-cyano-3-(2,4-dimethoxyphenyl)acrylic acid) and 34-SC ((E)-2-cyano-3-(3,4-dimethoxyphenyl)acrylic acid), containing methoxy groups as a donor and the acrylic acid as an acceptor were synthesized and characterized by CHN, FT-IR, UV-Vis, {sup 1}H-NMR and single crystal X-ray diffraction and used as photosensitizers for the application of dye-sensitized solar cells (DSSC). The sensitizing characteristics of them were evaluated. Both compounds contain the natural molecule, its anionic form and the piperidinium cation and they differ by number of these molecules in the asymmetric unit. To get further insight into the effect of molecular structure on the performance of DSSC, their geometry and energies of HOMO and LUMO were optimized by density functional theory calculation at the B3LYP/6-31G(d) level with Gaussian 03. Overall conversion efficiencies of 0.78 under full sunlight irradiation are obtained for DSSCs based on the new metal-free organic dyes 24-SC and 34-SC.

  1. Synthesis of Amphiphilic Hyperbranched AIE-active Fluorescent Organic Nanoparticles and Their Application in Biological Application.

    Science.gov (United States)

    Lv, Qiulan; Wang, Ke; Xu, Dazhuang; Liu, Meiying; Wan, Qing; Huang, Hongye; Liang, Shangdong; Zhang, Xiaoyong; Wei, Yen

    2016-02-01

    Aggregation-induced emission (AIE) dyes have recently attracted much attention for biomedical applications for their remarkable AIE properties. However, the hydrophobic nature of AIE dyes made them difficult to be dispersed in physiological solution and problematic for biomedical application directly. Great efforts have been made to overcome this problem, and different strategies for preparation of water dispersible AIE based nanoprobes had been explored previously. However, a facile and effective strategy is still highly desirable and of great importance for the biomedical applications of AIE dye based on nanoprobes. In this work, the fabrication of amphiphilic hyperbranched fluorescent organic nanoparticles with a core-shell structure based on an AIE dye [tetraphenylethene acrylate (TPE-O-E)] and a hyperbranched polyamino compound [polyethylene imine (PEI)] through Michael addition reaction is described for the first time. The AIE dye as well as the final product PEI-TPE-O-E was characterized in detail by a number of techniques. To test their biomedical application potential, the cell viability as well as cell imaging properties of the PEI-TPE-O-E was also examined. The results showed that the PEI-TPE-O-E organic nanoparticles presented high water dispersiblity, ultrabright fluroerescence, low cytotoxicity and excellent biocompatibility, making them promising for biological imaging and gene delivery applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. SnO2 thin film synthesis for organic vapors sensing at ambient temperature

    Directory of Open Access Journals (Sweden)

    N.H. Touidjen

    2016-12-01

    Full Text Available The present work is a study of tin dioxide (SnO2 based thin sensitive layer dedicated to organic vapors detection at ambient temperature. SnO2 thin film was deposited by chemical spray pyrolysis technique. The glass substrate temperature was kept to 400 °C, using a starting solution of 0.1 M tin (II dichloride dihydrate (SnCl2, 2H2O. Films structural and morphological properties were characterized using X-ray diffraction (XRD, scanning electron microscopy (SEM and atomic force microscope (AFM respectively. Films optical characteristics were studied using UV-VIS spectrophotometer. XRD revealed the presence of pure SnO2 polycrystalline thin film with a tetragonal rutile structure. The SEM and AFM observations confirmed the granular morphology with presence of pores in the film surface. The prepared film was tested in various organic vapors (ethanol, methanol and acetone at ambient operating temperature (25 °C ± 2 °C. The obtained results suggested that SnO2 is more sensitive to ethanol vapor with a maximum sensitivity of 35% higher than to methanol and acetone vapors (1% and 3%. The realized SnO2 based sensor demonstrated fast response and recovery times as revealed by the values of 2 s to 3 s towards 47 ppm of ethanol vapor. Keywords: SnO2 thin film, Sensitivity, XRD, SEM, AFM, UV–visible

  3. Chirality of meteoritic free and IOM-derived monocarboxylic acids and implications for prebiotic organic synthesis

    Science.gov (United States)

    Aponte, José C.; Tarozo, Rafael; Alexandre, Marcelo R.; Alexander, Conel M. O.'D.; Charnley, Steven B.; Hallmann, Christian; Summons, Roger E.; Huang, Yongsong

    2014-04-01

    The origin of homochirality and its role in the development of life on Earth are among the most intriguing questions in science. It has been suggested that carbonaceous chondrites seeded primitive Earth with the initial organic compounds necessary for the origin of life. One of the strongest pieces of evidence supporting this theory is that certain amino acids in carbonaceous chondrites display a significant L-enantiomeric excess (ee), similar to those use by terrestrial life. Analyses of ee in meteoritic molecules other than amino acids would shed more light on the origins of homochirality. In this study we investigated the stereochemistry of two groups of compounds: (1) free monocarboxylic acids (MCAs) from CM2 meteorites LON 94101 and Murchison; and (2) the aliphatic side chains present in the insoluble organic matter (IOM) and extracted in the form of monocarboxylic acids (MCAs) from EET 87770 (CR2) and Orgueil (CI1). Contrary to the well-known ee observed for amino acids in meteorites, we found that meteoritic branched free and IOM-derived MCAs with 5-8 carbon atoms are essentially racemic. The racemic nature of these compounds is used to discuss the possible influence of ultraviolet circularly polarized light (UVCPL) and aqueous alterations on the parent body on chirality observed in in carbonaceous chondrites.

  4. Synthesis and functionalization of gold nanorods for probing plasmonic enhancement mechanisms in organic photovoltaic active layers

    Science.gov (United States)

    Wadams, Robert Christopher

    DNA nanotechnology is one of the most flourishing interdisciplinary research fields. Through the features of programmability and predictability, DNA nanostructures can be designed to self-assemble into a variety of periodic or aperiodic patterns of different shapes and length scales, and more importantly, they can be used as scaffolds for organizing other nanoparticles, proteins and chemical groups. By leveraging these molecules, DNA nanostructures can be used to direct the organization of complex bio-inspired materials that may serve as smart drug delivery systems and in vitro or in vivo bio-molecular computing and diagnostic devices. In this dissertation I describe a systematic study of the thermodynamic properties of complex DNA nanostructures, including 2D and 3D DNA origami, in order to understand their assembly, stability and functionality and inform future design endeavors. It is conceivable that a more thorough understanding of DNA self-assembly can be used to guide the structural design process and optimize the conditions for assembly, manipulation, and functionalization, thus benefiting both upstream design and downstream applications. As a biocompatible nanoscale motif, the successful integration, stabilization and separation of DNA nanostructures from cells/cell lysate suggests its potential to serve as a diagnostic platform at the cellular level. Here, DNA origami was used to capture and identify multiple T cell receptor mRNA species from single cells within a mixed cell population. This demonstrates the potential of DNA nanostructure as an ideal nano scale tool for biological applications.

  5. Synthesis of nanoporous carbohydrate metal-organic framework and encapsulation of acetaldehyde

    Science.gov (United States)

    Al-Ghamdi, Saleh; Kathuria, Ajay; Abiad, Mohamad; Auras, Rafael

    2016-10-01

    Gamma cyclodextrin (γ-CD) metal organic frameworks (CDMOFs) were synthesized by coordinating γ-CDs with potassium hydroxide (KOH), referred hereafter as CDMOF-a, and potassium benzoate (C7H5KO2), denoted as CDMOF-b. The obtained CDMOF structures were characterized using nitrogen sorption isotherm, thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). High surface areas were achieved by the γ-CD based MOF structures where the Langmuir specific surface areas (SSA) of CDMOF-a and CDMOF-b were determined as 1376 m2 g-1 and 607 m2 g-1; respectively. The dehydrated CDMOF structures demonstrated good thermal stability up to 250 °C as observed by the TGA studies. XRD results for CDMOF-a and CDMOF-b reveal a body centered-cubic (BCC) and trigonal crystal system; respectively. Due to its accessible porous structure and high surface area, acetaldehyde was successfully encapsulated in CDMOF-b. During the release kinetic studies, we observed peak release of 53 μg of acetaldehyde per g of CDMOF-b, which was 100 times greater than previously reported encapsulation in β-CD. However, aldol condensation reaction occurred during encapsulation of acetaldehyde into CDMOF-a. This research work demonstrates the potential to encapsulate volatile organic compounds in CDMOF-b, and their associated release for applications including food, pharmaceuticals and packaging.

  6. Synthesis and properties of imidazole-grafted hybrid inorganic-organic polymer membranes

    International Nuclear Information System (INIS)

    Li Siwen; Zhou Zhen; Liu Meilin; Li Wen; Ukai, Junzo; Hase, Kohei; Nakanishi, Masatsugu

    2006-01-01

    Imidazole rings were grafted on alkoxysilane with a simple nucleophilic substitute reaction to form hybrid inorganic-organic polymers with imidazole rings. Proton exchange membranes (PEM) based on these hybrid inorganic-organic polymers and H 3 PO 4 exhibit high proton conductivity and high thermal stability in an atmosphere of low relative humidity. The grafted imidazole rings improved the proton conductivity of the membranes in the high temperature range. It is found that the proton conductivities increase with H 3 PO 4 content and temperature, reaching 3.2 x 10 -3 S/cm at 110 deg. C in a dry atmosphere for a membrane with 1 mole of imidazole ring and 7 moles of H 3 PO 4 . The proton conductivity increases with relative humidity (RH) as well, reaching 4.3 x 10 -2 S/cm at 110 deg. C when the RH is increased to about 20%. Thermogravimetric analysis (TGA) indicates that these membranes are thermally stable up to 250 deg. C in dry air, implying that they have a good potential to be used as the membranes for high-temperature PEM fuel cells

  7. Effects of chemical structure on the thermodynamic efficiency of radical chain carriers for organic synthesis.

    Science.gov (United States)

    Lin, Ching Yeh; Peh, Jessie; Coote, Michelle L

    2011-03-18

    The chain carrier index (CCI), defined as the ratio of the bond dissociation free energies (BDFE) of corresponding chain carrier halides and hydrides, is proposed as a measure of the thermodynamic efficiency of chain carriers for radical dehalogenation. The larger this value is relative to the corresponding value of the organic substrate, the more thermodynamically efficient the process. The chloride and bromide CCIs were evaluated at the G3(MP2)-RAD(+) level of theory for 120 different R-groups, covering a broad range of carbon-centered and noncarbon-centered species; the effects of solvent and temperature have also been studied. The broad finding from this work is that successful chain carriers generally maximize the strength of their halide (versus hydride bonds) through charge-shift bonding. As a result, the thermodynamic efficiency of a chain carrier tends to increase down the periodic table, and also with the inclusion of stronger electron donating substituents. The CCIs of carbon-centered species fall into a relatively narrow range so that, even when the CCI is maximized through inclusion of lone pair donor OMe or NMe(2) groups, the thermodynamic driving force for dehalogenation of other organic substrates is modest at best, and the process is likely to be kinetically hampered. Among the noncarbon-centered species studied, bismuth- and borane-centered compounds have some of the highest CCI values and, although their kinetics requires further optimization, these classes of compounds would be worth further investigation as tin-free radical reducing agents.

  8. Design and Synthesis of Novel Porous Metal-Organic Frameworks (MOFs) Toward High Hydrogen Storage Capacity

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Eddaoudi [USF; Zaworotko, Michael [USF; Space, Brian [USF; Eckert, Juergen [USF

    2013-05-08

    Statement of Objectives: 1. Synthesize viable porous MOFs for high H2 storage at ambient conditions to be assessed by measuring H2 uptake. 2. Develop a better understanding of the operative interactions of the sorbed H2 with the organic and inorganic constituents of the sorbent MOF by means of inelastic neutron scattering (INS, to characterize the H2-MOF interactions) and computational studies (to interpret the data and predict novel materials suitable for high H2 uptake at moderate temperatures and relatively low pressures). 3. Synergistically combine the outcomes of objectives 1 and 2 to construct a made-to-order inexpensive MOF that is suitable for super H2 storage and meets the DOE targets - 6% H2 per weight (2kWh/kg) by 2010 and 9% H2 per weight (3kWh/kg) by 2015. The ongoing research is a collaborative experimental and computational effort focused on assessing H2 storage and interactions with pre-selected metal-organic frameworks (MOFs) and zeolite-like MOFs (ZMOFs), with the eventual goal of synthesizing made-to-order high H2 storage materials to achieve the DOE targets for mobile applications. We proposed in this funded research to increase the amount of H2 uptake, as well as tune the interactions (i.e. isosteric heats of adsorption), by targeting readily tunable MOFs:

  9. Controllable synthesis of organic-inorganic hybrid MoOx/polyaniline nanowires and nanotubes.

    Science.gov (United States)

    Wang, Sinong; Gao, Qingsheng; Zhang, Yahong; Gao, Jing; Sun, Xuhui; Tang, Yi

    2011-02-01

    A novel chemical oxidative polymerization approach has been proposed for the controllable preparation of organic-inorganic hybrid MoO(x)/polyaniline (PANI) nanocomposites based on the nanowire precursor of Mo(3)O(10)(C(6)H(8)N)(2)·2H(2)O with sub-nanometer periodic structures. The nanotubes, nanowires, and rambutan-like nanoparticles of MoO(x)/PANI were successfully obtained through simply modulating the pH values to 2.5-3.5, ≈2.0 and ≈1.0, respectively. Through systematic physicochemical characterization, such as scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and so forth, the composition and structure of MoO(x)/PANI hybrid nanocomposites are well confirmed. It is found that the nanowire morphology of the precursor is the key to achieve the one-dimensional (1D) structures of final products. A new polymerization-dissolution mechanism is proposed to explain the formation of such products with different morphologies, in which the match between polymerization and dissolution processes of the precursor plays the important role. This approach will find a new way to controllably prepare various organic-inorganic hybrid 1D nanomaterials especially for polymer-hybrid nanostructures. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Mesoporous stilbene-based lanthanide metal organic frameworks: synthesis, photoluminescence and radioluminescence characteristics.

    Science.gov (United States)

    Mathis Ii, Stephan R; Golafale, Saki T; Bacsa, John; Steiner, Alexander; Ingram, Conrad W; Doty, F Patrick; Auden, Elizabeth; Hattar, Khalid

    2017-01-03

    Ultra large pore isostructural metal organic frameworks (MOFs) which exhibit both photoluminescence and scintillation properties, were synthesized from trans-4,4'-stilbenedicarboxylic acid (H 2 L) and trivalent lanthanide (Ln) metal salts under solvothermal conditions (Ln = Er 3+ (1) and Tm 3+ (2)). This new class of mesoporous materials is a non-interpenetrating network that features ultra-large diamond shaped pores of dimensions with approximate cross-sectional dimensions of 28 Å × 12 Å. The fully deprotonated ligand, L, is isolated and rigidified as it serves as the organic linker component of the MOF structure. Its low density unit cells possess asymmetric units with two crystallographically independent Ln 3+ ions in seven coordinate arrangements. A distinct feature of the structure is the bis-bidentate carboxylate groups. They serve as a ligand that coordinates two Ln(iii) ions while each L connects four Ln(iii) ions yielding an exceptionally large diamond-shaped rectangular network. The structure exhibits ligand-based photoluminescence with increased lifetime compared to free stilbene molecules on exposure to UV radiation, and also exhibits strong scintillation characteristics, comprising of both prompt and delayed radioluminescence features, on exposure to ionizing radiation.

  11. Osmolarity affects matrix synthesis in the nucleus pulposus associated with the involvement of MAPK pathways: A study of ex vivo disc organ culture system.

    Science.gov (United States)

    Li, Pei; Gan, Yibo; Xu, Yuan; Li, Songtao; Song, Lei; Li, Sukai; Li, Huijuan; Zhou, Qiang

    2016-06-01

    Matrix homeostasis within the nucleus pulposus (NP) is important for disc function. Unfortunately, the effects of osmolarity on NP matrix synthesis in a disc organ culture system and the underlying mechanisms are largely unknown. The present study was to investigate the effects of different osmolarity modes (constant and cyclic) and osmolarity levels (hypo-, iso-, and hyper-) on NP matrix synthesis using a disc organ culture system and determine whether ERK1/2 or p38MAPK pathway has a role in this process. Porcine discs were cultured for 7 days in various osmotic media, including constant hypo-, iso-, hyper-osmolarity (330, 430, and 550 mOsm/kg, respectively) and cyclic-osmolarity (430 mOsm/kg for 8 h, followed by 550 mOsm/kg for 16 h). The role of ERK1/2 and p38MAPK pathways were determined by their inhibitors U0126 and SB202190 respectively. The expression of SOX9 and downstream aggrecan and collagen II, biochemical content, and histology were used to assess NP matrix synthesis. The findings revealed that NP matrix synthesis was promoted in iso- and cyclic-osmolarity cultures compared to hypo- or hyper-osmolarity culture although the level of matrix synthesis in cyclic-osmolarity culture did not reach that in iso-osmolarity culture. Further analysis suggested that inhibition of the ERK1/2 or p38MAPK pathway in iso- and cyclic-osmolarity cultures reduced NP matrix production. Therefore, we concluded that the effects of osmolarity on NP matrix synthesis depend on osmolarity level (hypo-, iso-, or hyper-) and osmolarity mode (constant or cyclic), and the ERK1/2 and p38MAPK pathways may participate in this process. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1092-1100, 2016. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  12. Hydrothermal synthesis, crystal structures and photoluminescence properties of mixed europium–yttrium organic frameworks

    International Nuclear Information System (INIS)

    Han Yinfeng; Fu Lianshe; Mafra, Luís; Shi, Fa-Nian

    2012-01-01

    Three mixed europium–yttrium organic frameworks: Eu 2−x Y x (Mel)(H 2 O) 6 (Mel=mellitic acid or benzene-1,2,3,4,5,6-hexacarboxylic acid, x=0.38 1, 0.74 2, and 0.86 3) have been synthesized and characterized. All the compounds contain a 3-D net with (4, 8)-flu topology. The study indicates that the photoluminescence properties are effectively affected by the different ratios of europium and yttrium ions, the quantum efficiency is increased and the Eu 3+ lifetime becomes longer in these MOFs than those of the Eu analog. - Graphical abstract: Three mixed europium and yttrium organic frameworks: Eu 2−x Y x (Mel)(H 2 O) 6 (Mel=mellitic acid) have been synthesized and characterized. All the compounds contain a 3-D net with (4, 8)-flu topology. The study indicates that the photoluminescence properties are effectively affected by the different ratios of europium and yttrium ions, the quantum efficiency is increased and the Eu 3+ lifetime becomes longer in these MOFs than those of the Eu analog. Highlights: ► Three (4, 8)-flu topological mixed Eu and Y MOFs were synthesized under mild conditions. ► Metal ratios were refined by the single crystal data consistent with the EDS analysis. ► Mixed Eu and Y MOFs show longer lifetime and higher quantum efficiency than the Eu analog. ► Adding inert lanthanide into luminescent MOFs enlarges the field of luminescent MOFs.

  13. Non-hydrolytic sol-gel synthesis of epoxysilane-based inorganic-organic hybrid resins

    International Nuclear Information System (INIS)

    Jana, Sunirmal; Lim, Mi Ae; Baek, In Chan; Kim, Chang Hae; Seok, Sang Il

    2008-01-01

    A silica-based inorganic-organic hybrid resins (IOHR) were synthesized by non-hydrolytic sol-gel process from 3-glycidoxypropyltrimethoxysilane (GLYMO) and diphenylsilanediol (DPSD) at a fixed amount of (20 mol%) phenyltrimethoxysilane using barium hydroxide as a catalyst. The confirmation of condensation reaction in the IOHR was done by liquid state 29 Si NMR (Nuclear Magnetic Resonance) spectroscopy, measurement of viscosity as well as weight average molecular weight (W m ) of the IOHR. The W m of the IOHR was varied from 1091 to 2151, depending upon the DPSD content. Fourier transform infrared (FTIR) spectroscopic measurements were performed to investigate the details of vibrational absorption bands in the IOHR. It was seen that up to 50 mol% of DPSD there were no absorption peaks in the region of 3000-3600 cm -1 responsible for O-H groups and it reappeared at 60 mol% of DPSD due to some unreacted OH groups present in the resin. The IOHR at all the compositions was oily transparent liquid, miscible with various organic solvents like toluene, cyclohexanone, chloroform, tehrahydrofuran (THF), etc., and also commercial epoxy resins but immiscible with water. The color of the IOHR was pale yellow, which lightened with increasing DPSD content. The IOHR having 40-50 mol% of DPSD were storable. The refractive index at 632.8 nm of the resin films varied from 1.556 to 1.588, depending upon the resin composition. Physico-chemical properties such as the thermal stability, visible transparency, etc. after curing were investigated as a function of the chemical composition

  14. Microbial synthesis of a branched-chain ester platform from organic waste carboxylates

    Directory of Open Access Journals (Sweden)

    Donovan S. Layton

    2016-12-01

    Full Text Available Processing of lignocellulosic biomass or organic wastes produces a plethora of chemicals such as short, linear carboxylic acids, known as carboxylates, derived from anaerobic digestion. While these carboxylates have low values and are inhibitory to microbes during fermentation, they can be biologically upgraded to high-value products. In this study, we expanded our general framework for biological upgrading of carboxylates to branched-chain esters by using three highly active alcohol acyltransferases (AATs for alcohol and acyl CoA condensation and modulating the alcohol moiety from ethanol to isobutanol in the modular chassis cell. With this framework, we demonstrated the production of an ester library comprised of 16 out of all 18 potential esters, including acetate, propionate, butanoate, pentanoate, and hexanoate esters, from the 5 linear, saturated C2-C6 carboxylic acids. Among these esters, 5 new branched-chain esters, including isobutyl acetate, isobutyl propionate, isobutyl butyrate, isobutyl pentanoate, and isobutyl hexanoate were synthesized in vivo. During 24 h in situ fermentation and extraction, one of the engineered strains, EcDL208 harnessing the SAAT of Fragaria ananassa produced ~63 mg/L of a mixture of butyl and isobutyl butyrates from glucose and butyrate co-fermentation and ~127 mg/L of a mixture of isobutyl and pentyl pentanoates from glucose and pentanoate co-fermentation, with high specificity. These butyrate and pentanoate esters are potential drop-in liquid fuels. This study provides better understanding of functional roles of AATs for microbial biosynthesis of branched-chain esters and expands the potential use of these esters as drop-in biofuels beyond their conventional flavor, fragrance, and solvent applications. Keywords: Carboxylate platform, Ester platform, Branched-chain ester, Modular cell, Biological upgrading, Organic waste, Lignocellulosic biomass, Isobutyl esters

  15. Synthesis and characterization of the europium (III) complex as an organic luminescent material

    International Nuclear Information System (INIS)

    Zhuo Zuliang; Zhang Fujun; Xu Zheng; Lu Lifang; Li Junming; Wang Yongsheng; Lv Yuguang

    2010-01-01

    The red emission organic material Eu(coumarin) 3 ·2H 2 O complex was synthesized and its morphology, energy level alignment and luminescence characteristics were studied by using scanning electron microscopy, Fourier transform infrared spectra, cyclic voltammetry and ultraviolet-visible absorption spectra and fluorescence spectra. Eu(coumarin) 3 ·2H 2 O shows bright red emission originating from Eu 3+ ions under 345 nm light excitation. The luminescence lifetime of Eu 3+ in this complex is about 580 μs. To improve the quality of Eu(coumarin) 3 ·2H 2 O thin films, Eu(coumarin) 3 ·2H 2 O was doped with a poly(N-vinylcarbazole) (PVK) solution. The organic materials 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and aluminum quinoline (Alq 3 ) were used as hole-blocking and electron-transporting layers in our fabricated electroluminescence (EL) devices on indium tin oxide (ITO) substrates, respectively. The EL devices ITO/poly-(3,4-ethylenedioxythiophene):poly-(styrenesulphonic acid) (PEDOT:PSS)/emitting layer (PVK:Eu)/BCP/Alq 3 /Al were fabricated, and EL spectra were measured under different driving voltages. There is one emission peaking at 490 nm in addition to the characteristic emission peaks of Eu 3+ , which should be attributed to the spectral overlap between the PVK emission and electroplex emission originating from PVK and BCP interfaces. This explanation can be positively supported by the dependence of the EL spectral variation of ITO/ PVK/BCP/Alq 3 /Al devices on the driving voltage.

  16. Synthesis and characterization of the europium (III) complex as an organic luminescent material

    Science.gov (United States)

    Zhuo, Zuliang; Zhang, Fujun; Lv, Yuguang; Xu, Zheng; Lu, Lifang; Li, Junming; Wang, Yongsheng

    2010-11-01

    The red emission organic material Eu(coumarin)3·2H2O complex was synthesized and its morphology, energy level alignment and luminescence characteristics were studied by using scanning electron microscopy, Fourier transform infrared spectra, cyclic voltammetry and ultraviolet-visible absorption spectra and fluorescence spectra. Eu(coumarin)3·2H2O shows bright red emission originating from Eu3+ ions under 345 nm light excitation. The luminescence lifetime of Eu3+ in this complex is about 580 μs. To improve the quality of Eu(coumarin)3·2H2O thin films, Eu(coumarin)3·2H2O was doped with a poly(N-vinylcarbazole) (PVK) solution. The organic materials 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and aluminum quinoline (Alq3) were used as hole-blocking and electron-transporting layers in our fabricated electroluminescence (EL) devices on indium tin oxide (ITO) substrates, respectively. The EL devices ITO/poly-(3,4-ethylenedioxythiophene):poly-(styrenesulphonic acid) (PEDOT:PSS)/emitting layer (PVK:Eu)/BCP/Alq3/Al were fabricated, and EL spectra were measured under different driving voltages. There is one emission peaking at 490 nm in addition to the characteristic emission peaks of Eu3+, which should be attributed to the spectral overlap between the PVK emission and electroplex emission originating from PVK and BCP interfaces. This explanation can be positively supported by the dependence of the EL spectral variation of ITO/ PVK/BCP/Alq3/Al devices on the driving voltage.

  17. Synthesis and characterization of the europium (III) complex as an organic luminescent material

    Energy Technology Data Exchange (ETDEWEB)

    Zhuo Zuliang; Zhang Fujun; Xu Zheng; Lu Lifang; Li Junming; Wang Yongsheng [Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University), Ministry of Education, Beijing 100044 (China); Lv Yuguang, E-mail: fjzhang@bjtu.edu.c [The Provincial Key Laboratory of Biomaterials, College of Chemistry and Pharmacy, Jiamusi University, Jiamusi 154007 (China)

    2010-11-15

    The red emission organic material Eu(coumarin){sub 3{center_dot}}2H{sub 2}O complex was synthesized and its morphology, energy level alignment and luminescence characteristics were studied by using scanning electron microscopy, Fourier transform infrared spectra, cyclic voltammetry and ultraviolet-visible absorption spectra and fluorescence spectra. Eu(coumarin){sub 3{center_dot}}2H{sub 2}O shows bright red emission originating from Eu{sup 3+} ions under 345 nm light excitation. The luminescence lifetime of Eu{sup 3+} in this complex is about 580 {mu}s. To improve the quality of Eu(coumarin){sub 3{center_dot}}2H{sub 2}O thin films, Eu(coumarin){sub 3{center_dot}}2H{sub 2}O was doped with a poly(N-vinylcarbazole) (PVK) solution. The organic materials 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and aluminum quinoline (Alq{sub 3}) were used as hole-blocking and electron-transporting layers in our fabricated electroluminescence (EL) devices on indium tin oxide (ITO) substrates, respectively. The EL devices ITO/poly-(3,4-ethylenedioxythiophene):poly-(styrenesulphonic acid) (PEDOT:PSS)/emitting layer (PVK:Eu)/BCP/Alq{sub 3}/Al were fabricated, and EL spectra were measured under different driving voltages. There is one emission peaking at 490 nm in addition to the characteristic emission peaks of Eu{sup 3+}, which should be attributed to the spectral overlap between the PVK emission and electroplex emission originating from PVK and BCP interfaces. This explanation can be positively supported by the dependence of the EL spectral variation of ITO/ PVK/BCP/Alq{sub 3}/Al devices on the driving voltage.

  18. Current trends in genetic manipulations to enhance abiotic and ...

    African Journals Online (AJOL)

    Hitherto, tolerant plants were mainly produced by classical breeding techniques. Success in breeding for better adapted varieties to abiotic and biotic stresses depends on the concerted efforts of various research domains including plant and cell physiology, molecular biology, genetics and breeding. However, such process ...

  19. Effect of plant growth hormones and abiotic stresses on germination ...

    African Journals Online (AJOL)

    Phosphatases are widely found in plants having intracellular and extracellular activities. Phosphatases are believed to be important for phosphorous scavenging and remobilization in plants, but its role in adaptation to abiotic stresses and growth hormones at germination level has not been critically evaluated. To address ...

  20. STRESS ECOLOGY IN FUCUS : ABIOTIC, BIOTIC AND GENETIC INTERACTIONS

    NARCIS (Netherlands)

    Wahl, Martin; Jormalainen, Veijo; Eriksson, Britas Klemens; Coyer, James A.; Molis, Markus; Schubert, Hendrik; Dethier, Megan; Karez, Rolf; Kruse, Inken; Lenz, Mark; Pearson, Gareth; Rohde, Sven; Wikstrom, Sofia A.; Olsen, Jeanine L.; Lesser, M

    2011-01-01

    Stress regimes defined as the synchronous or sequential action of abiotic and biotic stresses determine the performance and distribution of species. The natural patterns of stress to which species are more or less well adapted have recently started to shift and alter under the influence of global

  1. Resilience of cereal crops to abiotic stress: A review

    African Journals Online (AJOL)

    SAM

    2014-07-16

    Jul 16, 2014 ... Key words: Cereal crops, abiotic stresses, food insecurity, molecular breeding, quantitative trait loci (QTLs), salinity, water stress. ... production of genetically modified (GM) crops, exo- genous use of osmo protectants etc. ... stressful environments is important to fulfill food demand of the ever-increasing world ...

  2. Understanding the Posttranscriptional Regulation of Plant Responses to Abiotic Stress

    KAUST Repository

    AlShareef, Sahar A.

    2017-06-01

    Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and biotic and abiotic stresses. Recent work showed that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various AS small-molecule inhibitors that perturb splicing and thereby provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Here, I show that the macrolide Pladienolide B (PB) and herboxidiene (GEX1A) inhibits both constitutive and alternative splicing, mimics an abiotic stress signal, and activates the abscisic acid (ABA) pathway in plants. Moreover, PB and GEX1A activate genome-wide transcriptional patterns involved in abiotic stress responses in plants. PB and GEX1A treatment triggered the ABA signaling pathway, activated ABA-inducible promoters, and led to stomatal closure. Interestingly, PB and GEX1A elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. This work establishes PB and GEX1A as potent splicing inhibitors in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

  3. Enzymatic synthesis of 6-O-glucosyl-poly(3-hydroxyalkanoate) in organic solvents and their binary mixture.

    Science.gov (United States)

    Gumel, A M; Annuar, M S M; Heidelberg, T

    2013-04-01

    The effects of organic solvents and their binary mixture in the glucose functionalization of bacterial poly-3-hydroxyalkanoates catalyzed by Lecitase™ Ultra were studied. Equal volume binary mixture of DMSO and chloroform with moderate polarity was more effective for the enzyme catalyzed synthesis of the carbohydrate polymer at ≈38.2 (±0.8)% reactant conversion as compared to the mono-phasic and other binary solvents studied. The apparent reaction rate constant as a function of medium water activity (aw) was observed to increase with increasing solvent polarity, with optimum aw of 0.2, 0.4 and 0.7 (±0.1) observed in hydrophilic DMSO, binary mixture DMSO:isooctane and hydrophobic isooctane, respectively. Molecular sieve loading between 13 to 15gL(-1) (±0.2) and reaction temperature between 40 to 50°C were found optimal. Functionalized PHA polymer showed potential characteristics and biodegradability. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. One step approach towards the green synthesis of silver decorated graphene nanocomposites for the degradation of organic dyes in water

    Science.gov (United States)

    Karthik, Gopakumar; Harith, A.; Nazrin Thazleema, N.; Vishal, Shaji; Jayan Jitha, S.; Saritha, Appukuttan

    2018-02-01

    Recently the decoration of graphene with metallic nanoparticles by a one pot reduction of graphene oxide (GO) coupled with the synthesis of metallic nanoparticles has gained momentum. Graphene and GO have been proved to exhibit excellent biocompatibility and high antibacterial activity and hence a vast possibility lies in the utilization of GO as an antibacterial reinforcement in biomaterials and exploration of the antiseptic properties as well as the cytotoxicity of GO-containing composites. Moreover GO decorated with metal / metal oxide paves way towards an inevitable role in water purification. The use of graphene oxide as the nano scale substrates for the development of nanocomposites with metal oxides is a novel idea to obtain a hybrid which would exhibit both the properties of GO as a enthralling paper-shape material and the quality of single nano-sized metal particles. The heavy metal ions and pollutants are considered as a major problem in environmental contamination. Hence detection of trace level pollutant has become a hot topic in the present research scenario. Modified graphene oxide nanocomposites prepared using a green approach has the capacity of absorbing pollutant material ions in high efficiency and selectivity. The green synthesized nanocomposites were characterized using FTIR and UV spectroscopy and the consequence of pH and concentration on the preparation of the nanocomposites was evaluated. The efficiency of these nanocomposites towards degradation of organic dyes like methylene blue has been evaluated.

  5. Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth

    International Nuclear Information System (INIS)

    Domagal-Goldman, Shawn D.; Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S.

    2014-01-01

    The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O 2 ) or ozone (O 3 ) simultaneous to methane (CH 4 ) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O 2 and O 3 production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O 2 and O 3 buildup, caused by fast chemical production of these gases. This results in detectable abiotic O 3 and CH 4 features in the UV-visible, but no detectable abiotic O 2 features. Thus, simultaneous detection of O 3 and CH 4 by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O 2 and O 3 is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.

  6. Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth

    Energy Technology Data Exchange (ETDEWEB)

    Domagal-Goldman, Shawn D. [Planetary Environments Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S., E-mail: shawn.goldman@nasa.gov [NASA Astrobiology Institute—Virtual Planetary Laboratory (United States)

    2014-09-10

    The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O{sub 2}) or ozone (O{sub 3}) simultaneous to methane (CH{sub 4}) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O{sub 2} and O{sub 3} production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O{sub 2} and O{sub 3} buildup, caused by fast chemical production of these gases. This results in detectable abiotic O{sub 3} and CH{sub 4} features in the UV-visible, but no detectable abiotic O{sub 2} features. Thus, simultaneous detection of O{sub 3} and CH{sub 4} by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O{sub 2} and O{sub 3} is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.

  7. Synthesis of organic nitrates of luteolin as a novel class of potent aldose reductase inhibitors.

    Science.gov (United States)

    Wang, Qi-Qin; Cheng, Ning; Zheng, Xiao-Wei; Peng, Sheng-Ming; Zou, Xiao-Qing

    2013-07-15

    Aldose reductase (AR) plays an important role in the design of drugs that prevent and treat diabetic complications. Aldose reductase inhibitors (ARIs) have received significant attentions as potent therapeutic drugs. Based on combination principles, three series of luteolin derivatives were synthesised and evaluated for their AR inhibitory activity and nitric oxide (NO)-releasing capacity in vitro. Eighteen compounds were found to be potent ARIs with IC50 values ranging from (0.099±0.008) μM to (2.833±0.102) μM. O(7)-Nitrooxyethyl-O(3'),O(4')-ethylidene luteolin (La1) showed the most potent AR inhibitory activity [IC50=(0.099±0.008) μM]. All organic nitrate derivatives released low concentrations of NO in the presence of l-cysteine. Structure-activity relationship studies suggested that introduction of an NO donor, protection of the catechol structure, and the ether chain of a 2-carbon spacer as a coupling chain on the luteolin scaffold all help increase the AR inhibitory activity of the resulting compound. This class of NO-donor luteolin derivatives as efficient ARIs offer a new concept for the development and design of new drug for preventive and therapeutic drugs for diabetic complications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Ionic Liquid/Metal-Organic Framework Composites: From Synthesis to Applications.

    Science.gov (United States)

    Kinik, Fatma Pelin; Uzun, Alper; Keskin, Seda

    2017-07-21

    Metal-organic frameworks (MOFs) have been widely studied for different applications owing to their fascinating properties such as large surface areas, high porosities, tunable pore sizes, and acceptable thermal and chemical stabilities. Ionic liquids (ILs) have been recently incorporated into the pores of MOFs as cavity occupants to change the physicochemical properties and gas affinities of MOFs. Several recent studies have shown that IL/MOF composites show superior performances compared with pristine MOFs in various fields, such as gas storage, adsorption and membrane-based gas separation, catalysis, and ionic conductivity. In this review, we address the recent advances in syntheses of IL/MOF composites and provide a comprehensive overview of their applications. Opportunities and challenges of using IL/MOF composites in many applications are reviewed and the requirements for the utilization of these composite materials in real industrial processes are discussed to define the future directions in this field. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Synthesis, structure, and photoluminescence properties of an organically-templated uranyl selenite

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dong-Sheng; Kuang, Han-Mao; Chen, Wen-Tong; Luo, Qiu-Yan; Sui, Yan [Institute of Applied Chemistry, School of Chemistry and Chemical Engineering, Jinggangshan University, Ji' an, Jiangxi 343009 (China)

    2015-09-15

    The organically-templated uranyl selenite, (H{sub 2}en)[(UO{sub 2})(SeO{sub 3})(HSeO{sub 3})](NO{sub 3}).0.5H{sub 2}O (1) (en = 1,2-ethylenediamine) was synthesized and characterized by elemental analyses, IR spectroscopy, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic system, space group Pbca, with a = 13.170(3) Aa, b = 11.055(2) Aa, c = 18.009(4) Aa, V = 2621.8(9) Aa{sup 3}, M = 1316.19, Z = 4, D{sub cal} = 3.334 g.cm{sup -3}, μ(Mo-K{sub α}) = 17.998 mm{sup -1}, GOF = 1.059, R{sub 1} = 0.0263, wR{sub 2} = 0.0532 [I>2σ(I)]. The X-ray diffraction analysis reveals that compound 1 has a three-dimensional (3D) supramolecular structure. It contains negatively charged [UO{sub 2}(HSeO{sub 3})(SeO{sub 3})]{sup -} inorganic anion layers and is balanced by [H{sub 2}en]{sup 2+} cations and NO{sub 3}{sup -} anions located in the interlayers. Furthermore, the photoluminescence properties of 1 were investigated. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Synthesis and characterization of cobalt ferrocyanides loaded on organic anion exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Valsala, T.P. [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India)], E-mail: tpvalsala@yahoo.co.in; Joseph, Annie [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Shah, J.G. [Back End Technology Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Raj, Kanwar [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Venugopal, V. [Radiochemistry and Isotope Group, Bhabha Atomic Research Centre, Trombay 400 085 (India)

    2009-02-15

    Transition metal ferrocyanides have important applications in the selective removal of radioactive caesium from low level and intermediate level radioactive liquid waste streams. The microcrystalline nature of these materials renders them useless for application in column mode operations. Special preparation procedures have been developed to prepare granular solids by in situ precipitation of metal ferrocyanides on organic anion exchangers, which is suitable for column mode operations. The elemental compositions of the metal ferrocyanides precipitated inside the pores of anion exchanger were determined by analysing the dissolved samples using ICP-AES system and flame photometer. From the XRD and EDX analyses and the elemental composition of the synthesized materials, the nature of the compound formed inside the anion exchanger was found to be cobalt ferrocyanide. From SEM analysis of the samples, the particle size of the cobalt ferrocyanide precipitated inside the anion exchanger was found to be much less than that of cobalt ferrocyanide precipitated outside. The efficiency of these materials for removal of Cs was evaluated by measuring the distribution coefficient (Kd), ion exchange capacity and kinetics of Cs uptake. The Kd of the materials loaded on anion exchanger was found to be of the order of 10{sup 5} ml/g. The Cs uptake kinetics of the materials loaded on anion exchanger was slower than that of precipitated materials. The ion exchange capacity of the cobalt ferrocyanide loaded on anion exchanger was found to be much higher than that of the precipitated cobalt ferrocyanide.

  11. Synthesis of ZnO-CuO/MCM-48 photocatalyst for the degradation of organic pollutions.

    Science.gov (United States)

    Duan, Yongzheng; Shen, Yulian

    2017-07-01

    The photocatalytic properties of ZnO-CuO catalysts supported on siliceous MCM-48 (Mobil Composition of Matter No. 48) for the degradation of organic pollutions such as methylene blue and salicylic acid under UV light irradiation were investigated. These catalysts were prepared by impregnation of MCM-48 with a mixed aqueous solution of copper acetate and zinc acetate. X-ray diffraction, N 2 -physisorption, high resolution transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and photoluminescence were used to characterize these samples. Results from characterizations showed that the addition of ZnO to CuO/MCM-48 could markedly improve the photocatalytic degradation properties. The enhanced photocatalytic behaviors of ZnO-CuO/MCM-48 may be due to the formation of p-n heterojunctions between ZnO and CuO, resulting in the effective separation of photogenerated electron-hole pairs. Moreover, the photocatalysts were easily recovered and reused for five cycles without considerable loss of activity.

  12. Synthesis, growth, structural, optical and thermal properties of a new organic salt crystal: 3-nitroanilinium trichloroacetate

    Science.gov (United States)

    Selvakumar, E.; Chandramohan, A.; Anandha Babu, G.; Ramasamy, P.

    2014-09-01

    A new organic non-linear optical salt 3-nitroanilinium trichloroacetate has been synthesized and single crystals grown by slow solvent evaporation solution growth technique at room temperature using methanol as the solvent. The 1H and 13C Nuclear magnetic resonance spectra were recorded to establish the molecular structure of the title salt. The crystal structure of the title crystal has been determined by single crystal X-ray diffraction analysis and it belongs to monoclinic crystal system with non-centrosymmetric space group P21. Fourier transform infrared spectral study has been carried out to confirm the presence of various functional groups. The optical transmittance spectrum was recorded in the range 200-2500 nm, to find the optical transmittance window and lower cut off wavelength. The thermo gravimetric and differential thermal analyses were carried out to establish the thermal stability of the title crystal. The second harmonic generation in the title crystal was confirmed by the modified Kurtz-Perry powder test employing the Nd: YAG laser as the source for infrared radiation.

  13. Synthesis, characterization and electrochemical investigations of mixed-ligand copper(II)-organic supramolecular frameworks

    Science.gov (United States)

    Singh, Sandeep K.; Srivastava, Ashish Kumar; Srivastava, Krishna; Banerjee, Rahul; Prasad, Jagdish

    2017-11-01

    Two mixed-ligand copper(II)-organic coordination compounds with 5,5‧-dimethyl-2,2‧-bipyridine (5,5‧-Me2bpy) as a primary ligand while aliphatic malonate (Hmal) and aromatic 2-hydroxynicotinate (2-OHNA) as secondary ligands, were synthesized. These complexes are formulated as: [Cu(Hmal)(5,5‧-Me2bpy)(H2O)](ClO4) 1 and [Cu2(2-OHNA)2(5,5‧-Me2bpy)2(NO3)](NO3) 2. These two complexes were structurally characterized by single crystal X-ray diffraction analysis. Characterization was further supported by powder X-ray diffraction analysis, elemental analyses, FT-IR, FAB-MASS and TGA, DSC studies. Cyclic voltammetric and UV-visible spectral studies of these two complexes have also been done. The electrochemical studies of complex 1 in DMSO and DMF have shown that this complex undergoes quasi-reversible diffusion-controlled one-electron transfer reaction without any chemical complication while complex 2 in DMSO undergoes quasi-reversible diffusion-controlled one electron transfer reaction, following EC mechanism. The electrochemical behaviour of complex 2 in DMF is complicated probably due to presence of more than one species in solution phase.

  14. Graphene-Templated Synthesis of Magnetic Metal Organic Framework Nanocomposites for Selective Enrichment of Biomolecules.

    Science.gov (United States)

    Cheng, Gong; Wang, Zhi-Gang; Denagamage, Sachira; Zheng, Si-Yang

    2016-04-27

    Successful control of homogeneous and complete coating of graphene or graphene-based composites with well-defined metal organic framework (MOF) layers is a great challenge. Herein, novel magnetic graphene MOF composites were constructed via a simple strategy for self-assembly of well-distributed, dense, and highly porous MOFs on both sides of graphene nanosheets. Graphene functionalized with magnetic nanoparticles and carboxylic groups on both sides was explored as the backbone and template to direct the controllable self-assembly of MOFs. The prepared composite materials have a relatively high specific surface area (345.4 m(2) g(-1)), and their average pore size is measured to be 3.2 nm. Their relatively high saturation magnetization (23.8 emu g(-1)) indicates their strong magnetism at room temperature. Moreover, the multifunctional composite was demonstrated to be a highly effective affinity material in selective extraction and separation of low-concentration biomolecules from biological samples, in virtue of the size-selection property of the unique porous structure and the excellent affinity of the composite materials. Besides providing a solution for the construction of well-defined functional graphene-based MOFs, this work could also contribute to selective extraction of biomolecules, in virtue of the universal affinity between immobilized metal ions and biomolecules.

  15. Synthesis and Electroluminescent Property of New Orange Iridium Compounds for Flexible White Organic Light Emitting Diodes.

    Science.gov (United States)

    Lee, Ho Won; Jeong, Hyunjin; Kim, Young Kwan; Ha, Yunkyoung

    2015-10-01

    Recently, white organic light-emitting diodes (OLEDs) have aroused considerable attention because they have the potential of next-generation flexible displays and white illuminated applications. White OLED applications are particularly heading to the industry but they have still many problems both materials and manufacturing. Therefore, we proposed that the new iridium compounds of orange emitters could be demonstrated and also applied to flexible white OLEDs for verification of potential. First, we demonstrated the chemical properties of new orange iridium compounds. Secondly, conventional two kinds of white phosphorescent OLEDs were fabricated by following devices; indium-tin oxide coated glass substrate/4,4'-bis[N-(napthyl)-N-phenylamino]biphenyl/N,N'-dicarbazolyl-3,5-benzene doped with blue and new iridium compounds for orange emitting 8 wt%/1,3,5-tris[N-phenylbenzimidazole-2-yl]benzene/lithium quinolate/aluminum. In addition, we fabricated white OLEDs using these emitters to verify the potential on flexible substrate. Therefore, this work could be proposed that white light applications can be applied and could be extended to additional research on flexible applications.

  16. Anthracene-Based Lanthanide Metal-Organic Frameworks: Synthesis, Structure, Photoluminescence, and Radioluminescence Properties

    Directory of Open Access Journals (Sweden)

    Stephan R. Mathis

    2018-01-01

    Full Text Available Four anthracene-based lanthanide metal-organic framework structures (MOFs were synthesized from the combination of the lanthanide ions, Eu3+, Tb3+, Er3+, and Tm3+, with 9,10-anthracenedicarboxylic acid (H2ADC in dimethylformamide (DMF under hydrothermal conditions. The 3-D networks crystalize in the triclinic system with P-1 space group with the following compositions: (i {{[Ln2(ADC3(DMF4·DMF]}n, Ln = Eu (1 and Tb (2} and (ii {{[Ln2(ADC3(DMF2(OH22·2DMF·H2O]}n, Ln = Er (3 and Tm (4}. The metal centers exist in various coordination environments; nine coordinate in (i, while seven and eight coordinate in (ii. The deprotonated ligand, ADC, assumes multiple coordination modes, with its carboxylate functional groups severely twisted away from the plane of the anthracene moiety. The structures show ligand-based photoluminescence, which appears to be significantly quenched when compared with that of the parent H2ADC solid powder. Structure 2 is the least quenched and showed an average photoluminescence lifetime from bi-exponential decay of 0.3 ns. On exposure to ionizing radiation, the structures show radioluminescence spectral features that are consistent with the isolation of the ligand units in its 3-D network. The spectral features vary among the 3-D networks and appear to suggest that the latter undergo significant changes in their molecular and/or electronic structure in the presence of the ionizing radiation.

  17. Changes in plasma melatonin levels and pineal organ melatonin synthesis following acclimation of rainbow trout (Oncorhynchus mykiss) to different water salinities.

    Science.gov (United States)

    López-Patiño, Marcos A; Rodríguez-Illamola, Arnau; Gesto, Manuel; Soengas, José L; Míguez, Jesús M

    2011-03-15

    Melatonin has been suggested to play a role in fish osmoregulation, and in salmonids has been related to the timing of adaptive mechanisms during smolting. It has been described that acclimation to different environmental salinities alters levels of circulating melatonin in a number of fish species, including rainbow trout. However, nothing is known regarding salinity effects on melatonin synthesis in the pineal organ, which is the main source of rhythmically produced and secreted melatonin in blood. In the present study we have evaluated, in rainbow trout, the effects of acclimation to different salinities on day and night plasma melatonin values and pineal organ melatonin synthesis. Groups of freshwater (FW)-adapted rainbow trout were placed in tanks with four different levels of water salinity (FW, 6, 12, 18 p.p.t.; parts per thousand) and maintained for 6 h or 5 days. Melatonin content in plasma and pineal organs, as well as the pineal content of serotonin (5-HT) and its main oxidative metabolite (5-hydroxyindole-3-acetic acid; 5-HIAA) were measured by high performance liquid chromatography. In addition, day-night changes in pineal organ arylalkylamine N-acetyltransferase (AANAT2) activity and aanat2 gene expression were studied. Plasma osmolalities were found to be higher in rainbow trout exposed to all salinity levels compared with the control FW groups. A salinity-dependent increase in melatonin content was found in both plasma and pineal organs. This effect was observed during the night, and was related to an increase in aanat2 mRNA abundance and AANAT2 enzyme activity, both of which also occurred during the day. Also, the levels of indoles (5-HT, 5-HIAA) in the pineal organ were negatively affected by increasing water salinity, which seems to be related to the higher recruitment of 5-HT as a substrate for the increased melatonin synthesis. A stimulatory effect of salinity on pineal aanat2 mRNA expression was also identified. These results indicate that

  18. Detection of Abiotic Methane in Terrestrial Continental Hydrothermal Systems: Implications for Methane on Mars

    Science.gov (United States)

    Socki, Richard A.; Niles, Paul B.; Gibson, Everett K., Jr.; Romanek, Christopher S.; Zhang, Chuanlun L.; Bissada, Kadry K.

    2008-01-01

    The recent detection of methane in the Martian atmosphere and the possibility that its origin could be attributed to biological activity, have highlighted the importance of understanding the mechanisms of methane formation and its usefulness as a biomarker. Much debate has centered on the source of the methane in hydrothermal fluids, whether it is formed biologically by microorganisms, diagenetically through the decomposition of sedimentary organic matter, or inorganically via reduction of CO2 at high temperatures. Ongoing research has now shown that much of the methane present in sea-floor hydrothermal systems is probably formed through inorganic CO2 reduction processes at very high temperatures (greater than 400 C). Experimental results have indicated that methane might form inorganically at temperatures lower still, however these results remain controversial. Currently, methane in continental hydrothermal systems is thought to be formed mainly through the breakdown of sedimentary organic matter and carbon isotope equilibrium between CO2 and CH4 is thought to be rarely present if at all. Based on isotopic measurements of CO2 and CH4 in two continental hydrothermal systems, we suggest that carbon isotope equilibration exists at temperatures as low as 155 C. This would indicate that methane is forming through abiotic CO2 reduction at lower temperatures than previously thought and could bolster arguments for an abiotic origin of the methane detected in the martian atmosphere.

  19. Mediterranean coastal dune systems: Which abiotic factors have the most influence on plant communities?

    Science.gov (United States)

    Ruocco, Matteo; Bertoni, Duccio; Sarti, Giovanni; Ciccarelli, Daniela

    2014-08-01

    Mediterranean coastal dunes are dynamic and heterogeneous ecosystems characterised by a strong interaction between abiotic and biotic factors. The present study aimed to adopt a multidisciplinary approach - integrating data on dune morphology, sediment texture and soil parameters as well as shoreline trend - in order to define which are the abiotic factors that most affect the distribution and composition of Mediterranean plant dune communities. The study was carried out in two protected areas, located in central Italy, subjected to different shoreline trends in recent years. 75 plots were identified along eleven randomly positioned cross-shore transects, starting from the beach continuing up to the plant communities of the backdunes. In each plot floristic and environmental data - such as distance to the coastline, plot altitude, inclination, shoreline trend, mean grain-size, sorting, pH, conductivity and organic matter concentration - were collected. The analyses revealed significant changes of vegetational cover, dune morphology and geopedological features along the coast-to-inland gradient. Relationships between vegetation composition and environmental factors were investigated through Canonical Correspondence Analysis (CCA). Four factors - distance to the coastline, mean grain-size, shoreline trend and organic matter - were found to be closely correlated with the floristic composition of plant communities. Finally, soil properties were highlighted as the most determinant factors of community zonation in these Mediterranean coastal dune ecosystems. These results could be taken into account by local managers in conservation actions such as protecting the eroding foredunes as well as in artificial dune reconstructions.

  20. Synthesis and self-organization of zinc β-(dialkoxyphosphoryl)porphyrins in the solid state and in solution.

    Science.gov (United States)

    Vinogradova, Ekaterina V; Enakieva, Yulia Y; Nefedov, Sergey E; Birin, Kirill P; Tsivadze, Aslan Y; Gorbunova, Yulia G; Bessmertnykh Lemeune, Alla G; Stern, Christine; Guilard, Roger

    2012-11-19

    The first synthesis and self-organization of zinc β-phosphorylporphyrins in the solid state and in solution are reported. β-Dialkoxyphosphoryl-5,10,15,20-tetraphenylporphyrins and their Zn(II) complexes have been synthesized in good yields by using Pd- and Cu-mediated carbon-phosphorous bond-forming reactions. The Cu-mediated reaction allowed to prepare the mono-β-(dialkoxyphosphoryl)porphyrins 1 Zn-3 Zn starting from the β-bromo-substituted zinc porphyrinate ZnTPPBr (TPP = tetraphenylporphyrin) and dialkyl phosphites HP(O)(OR)(2) (R = Et, iPr, nBu). The derivatives 1 Zn-3 Zn were obtained in good yields by using one to three equivalents of CuI. When the reaction was carried out in the presence of catalytic amounts of palladium complexes in toluene, the desired zinc derivative 1 Zn was obtained in up to 72% yield. The use of a Pd-catalyzed C-P bond-forming reaction was further extended to the synthesis of β-poly(dialkoxyphosphoryl)porphyrins. An unprecedented one-pot sequence involving consecutive reduction and phosphorylation of H(2)TPPBr(4) led to the formation of a mixture of the 2,12- and 2,13-bis(dialkoxy)phosphorylporphyrins 5 H(2) and 6 H(2) in 81% total yield. According to the X-ray diffraction studies, 1 Zn and 3 Zn are partially overlapped cofacial dimers formed through the coordination of two Zn centers by two phosphoryl groups belonging to the adjacent molecules. The equilibrium between the monomeric and the dimeric species exists in solutions of 1 Zn and 3 Zn in weakly polar solvents according to spectroscopic data (UV/Vis absorption and NMR spectroscopy). The ratio of each form is dependent on the concentration, temperature, and traces of water or methanol. These features demonstrated that zinc β-phosphorylporphyrins can be regarded as new model compounds for the weakly coupled chlorophyll pair in the photosynthesis process. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Mechanism for the Coupled Photochemistry of Ammonia and Acetylene: Implications for Giant Planets, Comets and Interstellar Organic Synthesis

    Science.gov (United States)

    Keane, Thomas C.

    2017-09-01

    Laboratory studies provide a fundamental understanding of photochemical processes in planetary atmospheres. Photochemical reactions taking place on giant planets like Jupiter and possibly comets and the interstellar medium are the subject of this research. Reaction pathways are proposed for the coupled photochemistry of NH3 (ammonia) and C2H2 (acetylene) within the context Jupiter's atmosphere. We then extend the discussion to the Great Red Spot, Extra-Solar Giant Planets, Comets and Interstellar Organic Synthesis. Reaction rates in the form of quantum yields were measured for the decomposition of reactants and the formation of products and stable intermediates: HCN (hydrogen cyanide), CH3CN (acetonitrile), CH3CH = N-N = CHCH3 (acetaldazine), CH3CH = N-NH2 (acetaldehyde hydrazone), C2H5NH2 (ethylamine), CH3NH2 (methylamine) and C2H4 (ethene) in the photolysis of NH3/C2H2 mixtures. Some of these compounds, formed in our investigation of pathways for HCN synthesis, were not encountered previously in observational, theoretical or laboratory photochemical studies. The quantum yields obtained allowed for the formulation of a reaction mechanism that attempts to explain the observed results under varying experimental conditions. In general, the results of this work are consistent with the initial observations of Ferris and Ishikawa (1988). However, their proposed reaction pathway which centers on the photolysis of CH3CH = N-N = CHCH3 does not explain all of the results obtained in this study. The formation of CH3CH = N-N = CHCH3 by a radical combination reaction of CH3CH = N• was shown in this work to be inconsistent with other experiments where the CH3CH = N• radical is thought to form but where no CH3CH = N-N = CHCH3 was detected. The importance of the role of H atom abstraction reactions was demonstrated and an alternative pathway for CH3CH = N-N = CHCH3 formation involving nucleophilic reaction between N2H4 and CH3CH = NH is advanced.

  2. Mechanism for the Coupled Photochemistry of Ammonia and Acetylene: Implications for Giant Planets, Comets and Interstellar Organic Synthesis.

    Science.gov (United States)

    Keane, Thomas C

    2017-09-01

    Laboratory studies provide a fundamental understanding of photochemical processes in planetary atmospheres. Photochemical reactions taking place on giant planets like Jupiter and possibly comets and the interstellar medium are the subject of this research. Reaction pathways are proposed for the coupled photochemistry of NH 3 (ammonia) and C 2 H 2 (acetylene) within the context Jupiter's atmosphere. We then extend the discussion to the Great Red Spot, Extra-Solar Giant Planets, Comets and Interstellar Organic Synthesis. Reaction rates in the form of quantum yields were measured for the decomposition of reactants and the formation of products and stable intermediates: HCN (hydrogen cyanide), CH 3 CN (acetonitrile), CH 3 CH = N-N = CHCH 3 (acetaldazine), CH 3 CH = N-NH 2 (acetaldehyde hydrazone), C 2 H 5 NH 2 (ethylamine), CH 3 NH 2 (methylamine) and C 2 H 4 (ethene) in the photolysis of NH 3 /C 2 H 2 mixtures. Some of these compounds, formed in our investigation of pathways for HCN synthesis, were not encountered previously in observational, theoretical or laboratory photochemical studies. The quantum yields obtained allowed for the formulation of a reaction mechanism that attempts to explain the observed results under varying experimental conditions. In general, the results of this work are consistent with the initial observations of Ferris and Ishikawa (1988). However, their proposed reaction pathway which centers on the photolysis of CH 3 CH = N-N = CHCH 3 does not explain all of the results obtained in this study. The formation of CH 3 CH = N-N = CHCH 3 by a radical combination reaction of CH 3 CH = N• was shown in this work to be inconsistent with other experiments where the CH 3 CH = N• radical is thought to form but where no CH 3 CH = N-N = CHCH 3 was detected. The importance of the role of H atom abstraction reactions was demonstrated and an alternative pathway for CH 3 CH = N-N = CHCH 3 formation involving nucleophilic reaction

  3. Two novel metal–organic coordination polymers based on diphosphonate and oxalate: Synthesis, structures and properties

    International Nuclear Information System (INIS)

    Niu, Qing-Jun; Zheng, Yue-Qing; Zhou, Lin-Xia; Zhu, Hong-Lin

    2015-01-01

    Two 2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonato and oxalic acid bridged coordination polymers (H 2 en)[Co 3 (H 2 zdn) 2 (ox)(H 2 O) 2 ] (1) and Cd 2 (H 2 zdn)(ox) 0.5 (H 2 O) (2) (2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonic acid=H 5 zdn; oxalic acid=H 2 ox) were synthesized under hydrothermal conditions and characterized by the infrared (IR), thermogravimetric analyses (TGA), elemental analyses (EA) and X-ray diffraction (XRD). Compound 1 is bridged by phosphonate anions to 1D chain, and further linked by oxalate anions to 2D layer. Compound 2 is bridged by O–P–O units of H 5 zdn to the layer, and then pillared by oxalate anions to generate 3D frameworks. Compound 1 shows anti-ferromagnetic behaviors analyzed with the temperature-dependent zero-field ac magnetic susceptibilities, while compound 2 exhibits an influence on the luminescent property. - Graphical abstract: Linked by oxalate, two zoledronate-based metal–organic frameworks are synthesized, which exhibits the different frameworks. Magnetism and luminescent properties have been studied. The weak antiferromagnetic coupling is conducted in 1. - Highlights: • Compound 1 and 2 are first linked by oxalate anion based on zoledronic acid. • Compound 1 generates a classic “dia Diamond” (6 6 ) topology. • Compound 2 exhibits a (4 4 ·6 2 )(4 4 ·6 6 ) topology. • Magnetism and luminescent properties of 1 and 2 have been studied, respectively

  4. The Role of MAPK Modules and ABA during Abiotic Stress Signaling

    KAUST Repository

    Zé licourt, Axel de; Colcombet, Jean; Hirt, Heribert

    2016-01-01

    To respond to abiotic stresses, plants have developed specific mechanisms that allow them to rapidly perceive and respond to environmental changes. The phytohormone abscisic acid (ABA) was shown to be a pivotal regulator of abiotic stress responses

  5. The Synthesis of "N"-Benzyl-2-Azanorbornene via Aqueous Hetero Diels-Alder Reaction: An Undergraduate Project in Organic Synthesis and Structural Analysis

    Science.gov (United States)

    Sauvage, Xavier; Delaude, Lionel

    2008-01-01

    The synthesis of "N"-benzyl-2-azanorbornene via aqueous hetero Diels-Alder reaction of cyclopentadiene and benzyliminium chloride formed in situ from benzylamine hydrochloride and formaldehyde is described. Characterization of the product was achieved by IR and NMR spectroscopies. The spectral data acquired are thoroughly discussed. Numerous…

  6. The impacts of prescribed moorland burning on water colour and dissolved organic carbon: a critical synthesis.

    Science.gov (United States)

    Holden, J; Chapman, P J; Palmer, S M; Kay, P; Grayson, R

    2012-06-30

    Discolouration of natural surface waters due to the humic component of dissolved organic carbon (DOC) is a costly problem for water supply companies. This paper reviews what is known about the impacts of prescribed moorland vegetation burning on water colour. Relevant research has taken place at three scales: laboratory experiments on peat cores, plot scale sampling of soil waters and catchment scale sampling of stream waters. While laboratory studies suggest burning increases colour production, the evidence from catchment and plot studies is contradictory. Plot studies suggest colour production may decrease or remain unchanged following burning although there is evidence for some transient changes. Catchment studies suggest prescribed moorland burning causes stream water colour to increase, although in most cases the evidence is not clear cut since most studies could not clearly disentangle the effects of burning from those of vegetation cover. The differences in findings between plot and catchment studies may be explained by: i) the short-term nature of some studies which do not measure long-term response and recovery times to burning; ii) the lack of colour measurements from shallow soil depths which contribute more to streamflow than soil water from deeper in the peat; and iii) the possibility of hydrological interactions occurring between different experimental plots at some sites. Additionally, the increase in recent patch burning in some catchments that has been statistically attributed by some authors to increases in stream water colour cannot be reconciled with theoretical calculations. When dilution with waters derived from other parts of the catchment are taken into account, large values of colour have to be theoretically derived from those recently burnt areas that occupy a small proportion of the catchment area in order to balance the change in stream water colour observed in recent years. Therefore, much further process-based work is required to

  7. Soil respiration in the cold desert environment of the Colorado Plateau (USA): Abiotic regulators and thresholds

    Science.gov (United States)

    Fernandez, D.P.; Neff, J.C.; Belnap, J.; Reynolds, R.L.

    2006-01-01

    Decomposition is central to understanding ecosystem carbon exchange and nutrient-release processes. Unlike mesic ecosystems, which have been extensively studied, xeric landscapes have received little attention; as a result, abiotic soil-respiration regulatory processes are poorly understood in xeric environments. To provide a more complete and quantitative understanding about how abiotic factors influence soil respiration in xeric ecosystems, we conducted soil- respiration and decomposition-cloth measurements in the cold desert of southeast Utah. Our study evaluated when and to what extent soil texture, moisture, temperature, organic carbon, and nitrogen influence soil respiration and examined whether the inverse-texture hypothesis applies to decomposition. Within our study site, the effect of texture on moisture, as described by the inverse texture hypothesis, was evident, but its effect on decomposition was not. Our results show temperature and moisture to be the dominant abiotic controls of soil respiration. Specifically, temporal offsets in temperature and moisture conditions appear to have a strong control on soil respiration, with the highest fluxes occurring in spring when temperature and moisture were favorable. These temporal offsets resulted in decomposition rates that were controlled by soil moisture and temperature thresholds. The highest fluxes of CO2 occurred when soil temperature was between 10 and 16??C and volumetric soil moisture was greater than 10%. Decomposition-cloth results, which integrate decomposition processes across several months, support the soil-respiration results and further illustrate the seasonal patterns of high respiration rates during spring and low rates during summer and fall. Results from this study suggest that the parameters used to predict soil respiration in mesic ecosystems likely do not apply in cold-desert environments. ?? Springer 2006.

  8. Effects of solar radiation on the abiotic and bacterially mediated carbon flux in aquatic ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Anesio, A.M.

    2000-05-01

    In this thesis, I studied some of the current aspects of organic matter photochemistry. I analyzed abiotic photo transformations of several types of dissolved (DOM) and particulate organic matter (POM). I also evaluated the effects of photo transformation of several types of DOM on bacteria. Finally, in a field experiment, I analyzed net effects of solar radiation on organic matter decomposition. DOM undergoes several transformations due to solar irradiation. One such transformation is photooxidation of organic matter into inorganic carbon. Results of this Thesis show that photooxidation is ubiquitous to all kinds of organic matter in both dissolved and particulate forms. The intensity of this process depends on several factors, including DOM composition, radiation type and time of exposure. Besides mineralization to inorganic carbon, DOM undergoes other chemical transformations due to UV radiation, with profound consequences to DOM availability for bacteria. Bioavailability was tested by measuring bacterial growth and respiration on irradiated and nonirradiated DOM from several types of humic matter and plant leachates. Irradiation of freshly-leached DOM often produced negative effects on bacteria, whereas irradiation of humic material was followed by stimulation of bacterial growth. The degree of stimulation seems to be related to the initial bioavailability of the DOM and to the capability of the DOM to produce hydrogen peroxide upon irradiation. Other factors also accounted for differences in bacterial response to photochemical modification of DOM, including length and type of irradiation exposure. The effects of solar radiation on litter decomposition were also evaluated using experiments that more closely mimic natural conditions. I could not observe differences between dry weight loss of leaves and culms exposed to solar radiation or kept in darkness, which may be explained by the fact that abiotic decomposition under solar radiation is counterbalanced by

  9. The shifting influence of abiotic drivers during landslide succession in Puerto Rico

    Science.gov (United States)

    L. R. Walker; A. B. Shiels; P. J. Bellingham; A. D. Sparrow; N. Fetcher; F. H. Landau; D. J. Lodge

    2013-01-01

    Summary 1. Abiotic variables are critical drivers of succession in most primary seres, but how their influence on biota changes over time is rarely examined. Landslides provide good model systems for examining abiotic influences because they are spatially and temporally heterogeneous habitats with distinct abiotic and biotic gradients and post-landslide erosion. 2. In...

  10. Organo catalysis reactions with chiral amines: mechanistic aspects and uses on organic synthesis; Reacoes de organocatalise com aminas quirais: aspectos mecanisticos e aplicacoes em sintese organica

    Energy Technology Data Exchange (ETDEWEB)

    Amarante, Giovanni W.; Coelho, Fernando [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica]. E-mail: coelho@iqm.unicamp.br

    2009-07-01

    The philosophy of organocatalysis is based on the utilization of organic compounds to catalyze organic transformations without the intervention of metals. This area has attracted much attention of the synthetic chemistry community on the last years, which can be confirmed by the explosion of published papers dealing with this subject. Phosphorus compounds, urea and thiourea derivatives, alkaloids, guanidine derivatives, for example, have already been used as organocatalysts. In this review we have focused on the use of chiral amines as organocatalyst. We have also chosen some outstanding examples to demonstrate the potentiality of this strategy in the synthesis of natural products and biologically active compounds. (author)

  11. Compostos alfa-diazo carbonílicos: uma estratégia atraente para a síntese orgânica alpha-diazo carbonyl compounds: an atractive estrategy in organic synthesis

    Directory of Open Access Journals (Sweden)

    Vítor F. Ferreira

    2001-08-01

    Full Text Available Diazocarbonyl compounds are a very important class of organic substances which have a long history of useful aplications in organic chemistry. The focus of this report deals with the use of diazocarbonyl compounds in a ariety of important reactions and their application in organic synthesis. These reactions are briefly summarized showing their broad scope.

  12. Abiotic/biotic coupling in the rhizosphere: a reactive transport modeling analysis

    Science.gov (United States)

    Lawrence, Corey R.; Steefel, Carl; Maher, Kate

    2014-01-01

    A new generation of models is needed to adequately simulate patterns of soil biogeochemical cycling in response changing global environmental drivers. For example, predicting the influence of climate change on soil organic matter storage and stability requires models capable of addressing complex biotic/abiotic interactions of rhizosphere and weathering processes. Reactive transport modeling provides a powerful framework simulating these interactions and the resulting influence on soil physical and chemical characteristics. Incorporation of organic reactions in an existing reactive transport model framework has yielded novel insights into soil weathering and development but much more work is required to adequately capture root and microbial dynamics in the rhizosphere. This endeavor provides many advantages over traditional soil biogeochemical models but also many challenges.

  13. Biomolecule-assisted synthesis of In(OH)₃ nanocubes and In₂O₃ nanoparticles: photocatalytic degradation of organic contaminants and CO oxidation.

    Science.gov (United States)

    Nayak, Arpan Kumar; Lee, Seungwon; Sohn, Youngku; Pradhan, Debabrata

    2015-12-04

    The synthesis of nanostructured materials without any hazardous organic chemicals and expensive capping reagents is one of the challenges in nanotechnology. Here we report on the L-arginine (a biomolecule)-assisted synthesis of single crystalline cubic In(OH)3 nanocubes of a size in the range of 30-60 nm along the diagonal using hydrothermal methods. Upon calcining at 750 °C for 1 h in air, In(OH)3 nanocubes are transformed into In2O3 nanoparticles (NPs) with voids. The morphology transformation and formation of voids with the increase of the calcination temperature is studied in detail. The possible mechanism of the voids' formation is discussed on the basis of the Kirkendall effect. The photocatalytic properties of In(OH)3 nanocubes and In2O3 NPs are studied for the degradation of rhodamin B and alizarin red S. Furthermore, the CO oxidation activity of In(OH)3 nanocubes and In2O3 NPs is examined. The photocatalytic and CO oxidation activity are measured to be higher for In2O3 NPs than for In(OH)3 nanocubes. This is attributed to the lower energy gap and higher specific surface area of the former. The present green synthesis has potential for the synthesis of other inorganic nanomaterials.

  14. B cells in the appendix and other lymphoid organs of the rabbit: stimulation of DNA synthesis by anti-immunoglobulin

    International Nuclear Information System (INIS)

    Calkins, C.E.; Ozer, H.; Waksman, B.H.

    1975-01-01

    Lymphocytes from rabbit lymphoid organs were cultured in the presence of class specific anti-immunoglobulin sera and of anti-allotype sera. Stimulation of tritiated thymidine uptake into DNA was taken to indicate the presence of the corresponding immunoglobulins on the cell surfaces. Thymus and bone marrow lymphocytes were unresponsive to all reagents tested. Popliteal lymph node contained cells responsive to anti-μ, anti-γ, and anti-α and therefore presumably bearing IgM, IgG, and IgA. Spleen had only IgM- and IgG-bearing cells, and the appendix contained cells with IgM and IgA receptors only. The lymph node, spleen, and appendix cells of rabbits depleted of B lymphocytes by irradiation (900 R) and injection of thymocytes were unresponsive to anti-immunoglobulin but were stimulated at almost normal levels by PHA and Con A. T cell-depleted animals (thymectomy, irradiation with three divided doses of 450 R and bone marrow shielding) had immunoglobulin-bearing lymphocytes but were unresponsive to the mitogens. However a moderate level of mitogen-responsiveness reappeared by 3 to 4 wk after irradiation. Cells of morphologically distinct regions of the appendix, separated manually, showed different responses corresponding to the inferred origins of these anatomic areas. The ''dome'' and ''corona'' contained functional IgM- and IgA-bearing cells. The ''TDA'' reacted well to PHA, Con A, and PWM, but was depleted of immunoglobulin-bearing cells. The ''follicle'' cells, which are almost all in active DNA synthesis or mitosis, were relatively unresponsive to either T or B cell stimuli. Anti-allotype serum stimulated the same populations which responded to class-specific heteroantisera but at a slightly lower level. It was inferred that gut-associated lymphoid tissues like the appendix may play a special role as an amplification site for B-cells destined to produce IgM and IgA elsewhere in the organism

  15. Plant Responses to Abiotic Stress Regulated by Histone Deacetylases

    Directory of Open Access Journals (Sweden)

    Ming Luo

    2017-12-01

    Full Text Available In eukaryotic cells, histone acetylation and deacetylation play an important role in the regulation of gene expression. Histone acetylation levels are modulated by histone acetyltransferases and histone deacetylases (HDACs. Recent studies indicate that HDACs play essential roles in the regulation of gene expression in plant response to environmental stress. In this review, we discussed the recent advance regarding the plant HDACs and their functions in the regulation of abiotic stress responses. The role of HDACs in autophagy was also discussed.

  16. Energy harvesting by implantable abiotically catalyzed glucose fuel cells

    Science.gov (United States)

    Kerzenmacher, S.; Ducrée, J.; Zengerle, R.; von Stetten, F.

    Implantable glucose fuel cells are a promising approach to realize an autonomous energy supply for medical implants that solely relies on the electrochemical reaction of oxygen and glucose. Key advantage over conventional batteries is the abundant availability of both reactants in body fluids, rendering the need for regular replacement or external recharging mechanisms obsolete. Implantable glucose fuel cells, based on abiotic catalysts such as noble metals and activated carbon, have already been developed as power supply for cardiac pacemakers in the late-1960s. Whereas, in vitro and preliminary in vivo studies demonstrated their long-term stability, the performance of these fuel cells is limited to the μW-range. Consequently, no further developments have been reported since high-capacity lithium iodine batteries for cardiac pacemakers became available in the mid-1970s. In recent years research has been focused on enzymatically catalyzed glucose fuel cells. They offer higher power densities than their abiotically catalyzed counterparts, but the limited enzyme stability impedes long-term application. In this context, the trend towards increasingly energy-efficient low power MEMS (micro-electro-mechanical systems) implants has revived the interest in abiotic catalysts as a long-term stable alternative. This review covers the state-of-the-art in implantable abiotically catalyzed glucose fuel cells and their development since the 1960s. Different embodiment concepts are presented and the historical achievements of academic and industrial research groups are critically reviewed. Special regard is given to the applicability of the concept as sustainable micro-power generator for implantable devices.

  17. Wheat EST resources for functional genomics of abiotic stress

    Directory of Open Access Journals (Sweden)

    Links Matthew G

    2006-06-01

    Full Text Available Abstract Background Wheat is an excellent species to study freezing tolerance and other abiotic stresses. However, the sequence of the wheat genome has not been completely characterized due to its complexity and large size. To circumvent this obstacle and identify genes involved in cold acclimation and associated stresses, a large scale EST sequencing approach was undertaken by the Functional Genomics of Abiotic Stress (FGAS project. Results We generated 73,521 quality-filtered ESTs from eleven cDNA libraries constructed from wheat plants exposed to various abiotic stresses and at different developmental stages. In addition, 196,041 ESTs for which tracefiles were available from the National Science Foundation wheat EST sequencing program and DuPont were also quality-filtered and used in the analysis. Clustering of the combined ESTs with d2_cluster and TGICL yielded a few large clusters containing several thousand ESTs that were refractory to routine clustering techniques. To resolve this problem, the sequence proximity and "bridges" were identified by an e-value distance graph to manually break clusters into smaller groups. Assembly of the resolved ESTs generated a 75,488 unique sequence set (31,580 contigs and 43,908 singletons/singlets. Digital expression analyses indicated that the FGAS dataset is enriched in stress-regulated genes compared to the other public datasets. Over 43% of the unique sequence set was annotated and classified into functional categories according to Gene Ontology. Conclusion We have annotated 29,556 different sequences, an almost 5-fold increase in annotated sequences compared to the available wheat public databases. Digital expression analysis combined with gene annotation helped in the identification of several pathways associated with abiotic stress. The genomic resources and knowledge developed by this project will contribute to a better understanding of the different mechanisms that govern stress tolerance in

  18. Abscisic Acid and Abiotic Stress Tolerance in Crop Plants

    Science.gov (United States)

    Sah, Saroj K.; Reddy, Kambham R.; Li, Jiaxu

    2016-01-01

    Abiotic stress is a primary threat to fulfill the demand of agricultural production to feed the world in coming decades. Plants reduce growth and development process during stress conditions, which ultimately affect the yield. In stress conditions, plants develop various stress mechanism to face the magnitude of stress challenges, although that is not enough to protect them. Therefore, many strategies have been used to produce abiotic stress tolerance crop plants, among them, abscisic acid (ABA) phytohormone engineering could be one of the methods of choice. ABA is an isoprenoid phytohormone, which regulates various physiological processes ranging from stomatal opening to protein storage and provides adaptation to many stresses like drought, salt, and cold stresses. ABA is also called an important messenger that acts as the signaling mediator for regulating the adaptive response of plants to different environmental stress conditions. In this review, we will discuss the role of ABA in response to abiotic stress at the molecular level and ABA signaling. The review also deals with the effect of ABA in respect to gene expression. PMID:27200044

  19. Cell Wall Metabolism in Response to Abiotic Stress

    Science.gov (United States)

    Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

    2015-01-01

    This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320

  20. Post-synthesis amine borane functionalization of metal-organic framework and its unusual chemical hydrogen release phenomenon

    KAUST Repository

    Berke, Heinz; Barman, Smair; Remhof, Arndt; Koitz, Ralph; Iannuzzi, Marcella; Blacque, Olivier; Yan, Yigang; Fox, Thomas; Hutter, Jü rg; Zü ttel, Andreas

    2017-01-01

    We report a novel strategy for post-synthesis amine borane functionalization of MOFs under gas-solid phase transformation utilizing gaseous diborane. The covalently confined amine borane derivative decorated on the framework backbone is stable when

  1. Life without water: cross-resistance of anhydrobiotic cell line to abiotic stresses

    Science.gov (United States)

    Gusev, Oleg

    2016-07-01

    Anhydrobiosis is an intriguing phenomenon of natural ability of some organisms to resist water loss. The larvae of Polypedilum vanderplanki, the sleeping chironomid is the largest and most complex anhydrobionts known to date. The larvae showed ability to survive variety of abiotic stresses, including outer space environment. Recently cell line (Pv11) derived from the embryonic mass of the chironomid was established. Initially sensitive to desiccation cells, are capable to "induced" anhydrobiosis, when the resistance to desiccation can be developed by pre-treatment of the cells with trehalose followed by quick desiccation. We have further conducted complex analysis of the whole genome transcription response of Pv11 cells to different abiotic stresses, including oxidative stress and irradiation. Comparative analysis showed that the gene set, responsible for formation of desiccation resistance (ARID regions in the genome) is also activated in response to other types of stresses and likely to contribute to general enhancing of the resistance of the cells to harsh environment. We have further demonstrated that the cells are able to protect recombinant proteins from harmful effect of desiccation

  2. Different effects of inorganic and dimethylated arsenic compounds on cell morphology, cytoskeletal organization, and DNA synthesis in cultured Chinese hamster V79 cells

    Energy Technology Data Exchange (ETDEWEB)

    Ochi, Takafumi; Nakajima, Fumie [Department of Environmental Toxicology, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa (Japan); Fukumori, Nobutaka [Department of Toxicology, Tokyo Metropolitan Research Laboratory of Public Health, Hyakuninchou, Shinjyuku (Japan)

    1998-09-01

    Changes in cytoskeletal organization of cultured V79 cells exposed to arsenite and dimethylarsinic acid (DMAA), a methylated derivative of inorganic arsenics, and related changes, such as mitotic arrest and induction of multinucleated cells, were investigated in comparison with their effects on DNA synthesis. DMAA caused mitotic arrest and induction of multinucleated cells with a delay of 12 h relative to the mitotic arrest. By contrast, arsenite at equitoxic concentrations to DMAA was less effective than DMAA in causing mitotic arrest and in inducing multinucleated cells. Post-mitotic incubation of cells arrested in metaphase by 6 h incubation with 10 mM DMAA showed that the incidence of multinucleated cells increased conversely with a rapid decrease in metaphase cells. This suggests that metaphase-arrested cells can escape from metaphase, resulting in the appearance of multinucleated cells. The mitotic arrest caused by DMAA was accompanied by disruption of the microtubule network. By contrast, both arsenite and DMAA did not cause disorganization of actin stress fibers even when incubated at concentrations that caused a marked retardation of cell growth. Cells exposed to arsenite for 6 h showed marked inhibition of DNA synthesis, whereas inhibition by DMAA was not observed. When incubation was prolonged by 18 h, the arsenite-induced inhibition of DNA synthesis was mitigated. By contrast, inhibition of DNA synthesis by DMAA occurred in parallel with an increase in the population of mitotic cells. These results suggest that DMAA caused growth retardation and morphological changes via disruption of the microtubule network, and that arsenite-induced retardation of cell growth and inhibition of DNA synthesis were not attributable to the cytoskeletal changes. (orig.) (orig.) With 7 figs., 31 refs.

  3. Evidence-informed health policy 1 - synthesis of findings from a multi-method study of organizations that support the use of research evidence.

    Science.gov (United States)

    Lavis, John N; Oxman, Andrew D; Moynihan, Ray; Paulsen, Elizabeth J

    2008-12-17

    Organizations have been established in many countries and internationally to support the use of research evidence by producing clinical practice guidelines, undertaking health technology assessments, and/or directly supporting the use of research evidence in developing health policy on an international, national, and state or provincial level. Learning from these organizations can reduce the need to 'reinvent the wheel' and inform decisions about how best to organize support for such organizations, particularly in low- and middle-income countries (LMICs). We undertook a multi-method study in three phases - a survey, interviews, and case descriptions that drew on site visits - and in each of the second and third phases we focused on a purposive sample of those involved in the previous phase. We used the seven main recommendations that emerged from the advice offered in the interviews to organize much of the synthesis of findings across phases and methods. We used a constant comparative method to identify themes from across phases and methods. Seven recommendations emerged for those involved in establishing or leading organizations that support the use of research evidence in developing health policy: 1) collaborate with other organizations; 2) establish strong links with policymakers and involve stakeholders in the work; 3) be independent and manage conflicts of interest among those involved in the work; 4) build capacity among those working in the organization; 5) use good methods and be transparent in the work; 6) start small, have a clear audience and scope, and address important questions; and 7) be attentive to implementation considerations, even if implementation is not a remit. Four recommendations emerged for the World Health Organization (WHO) and other international organizations and networks: 1) support collaborations among organizations; 2) support local adaptation efforts; 3) mobilize support; and 4) create global public goods. This synthesis of

  4. Evidence-informed health policy 1 – Synthesis of findings from a multi-method study of organizations that support the use of research evidence

    Directory of Open Access Journals (Sweden)

    Moynihan Ray

    2008-12-01

    Full Text Available Abstract Background Organizations have been established in many countries and internationally to support the use of research evidence by producing clinical practice guidelines, undertaking health technology assessments, and/or directly supporting the use of research evidence in developing health policy on an international, national, and state or provincial level. Learning from these organizations can reduce the need to 'reinvent the wheel' and inform decisions about how best to organize support for such organizations, particularly in low- and middle-income countries (LMICs. Methods We undertook a multi-method study in three phases – a survey, interviews, and case descriptions that drew on site visits – and in each of the second and third phases we focused on a purposive sample of those involved in the previous phase. We used the seven main recommendations that emerged from the advice offered in the interviews to organize much of the synthesis of findings across phases and methods. We used a constant comparative method to identify themes from across phases and methods. Results Seven recommendations emerged for those involved in establishing or leading organizations that support the use of research evidence in developing health policy: 1 collaborate with other organizations; 2 establish strong links with policymakers and involve stakeholders in the work; 3 be independent and manage conflicts of interest among those involved in the work; 4 build capacity among those working in the organization; 5 use good methods and be transparent in the work; 6 start small, have a clear audience and scope, and address important questions; and 7 be attentive to implementation considerations, even if implementation is not a remit. Four recommendations emerged for the World Health Organization (WHO and other international organizations and networks: 1 support collaborations among organizations; 2 support local adaptation efforts; 3 mobilize support; and 4 create

  5. Organics.

    Science.gov (United States)

    Chian, Edward S. K.; DeWalle, Foppe B.

    1978-01-01

    Presents water analysis literature for 1978. This review is concerned with organics, and it covers: (1) detergents and surfactants; (2) aliphatic and aromatic hydrocarbons; (3) pesticides and chlorinated hydrocarbons; and (4) naturally occurring organics. A list of 208 references is also presented. (HM)

  6. Organizers.

    Science.gov (United States)

    Callison, Daniel

    2000-01-01

    Focuses on "organizers," tools or techniques that provide identification and classification along with possible relationships or connections among ideas, concepts, and issues. Discusses David Ausubel's research and ideas concerning advance organizers; the implications of Ausubel's theory to curriculum and teaching; "webbing," a…

  7. Chemical behavior of phthalates under abiotic conditions in landfills.

    Science.gov (United States)

    Huang, Jingyu; Nkrumah, Philip N; Li, Yi; Appiah-Sefah, Gloria

    2013-01-01

    The phthalates comprise a family of phthalic acid esters that are used primarily as plasticizers in polymeric materials to impart flexibility during the manufacturing process and to the end product. It is estimated that the annual worldwide production of phthalate esters exceeds five million tons. Plasticizers are one of the most prominent classes of chemicals, but unfortunately, they possess endocrine-disrupting chemical properties. As endocrine-disrupting chemicals, plasticizers have produced adverse developmental and reproductive effects in mammalian animal models.Phthalates are easily transported into the environment during manufacture, disposal,and leaching from plastic materials, because they are not covalently bound to the plastics of which they are a component. Because of their fugitive nature and widespread use, the phthalates are commonly detected in air, water, sediment/soil, and biota, including human tissue. Large amounts of phthalic acid esters are often leached from the plastics that are dumped at municipal landfills.Phthalate esters undergo chemical changes when released into the environment.The primary processes by which they are transformed include hydrolysis, photolysis,and biodegradation. It is noteworthy that all of these degradation processes are greatly influenced by the local physical and chemical conditions. Hence, in the present review, we have sought to ascertain from the literature how the phthalate esters undergo transformation when they are released into lower landfill layers.Within the upper landfill layers, biodegradation prevails as the major degradation mechanism by which the phthalates are dissipated. Generally, biodegradation pathways for the phthalates consist of primary biodegradation from phthalate diesters to phthalate monoesters, then to phthalic acid, and ultimately biodegradation of phthalic acid to form C02 and/or CH4• We have noted that the phthalate esters are also degraded through abiotic means,which proceeds via

  8. Novel synthesis of magnesium hydroxide nanoparticles modified with organic phosphate and their effect on the flammability of acrylonitrile-butadiene styrene nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Attia, Nour F., E-mail: drnour2005@yahoo.com [Fire Protection Laboratory, Chemistry Division, National Institute of Standards, 136, Giza 12211 (Egypt); Goda, Emad S.; Nour, M.A. [Fire Protection Laboratory, Chemistry Division, National Institute of Standards, 136, Giza 12211 (Egypt); Sabaa, M.W. [Chemistry Department, Faculty of Science, Cairo University, NahdetMisr Street, Giza 12613 (Egypt); Hassan, M.A., E-mail: Mohamed_a_hassan@hotmail.com [Fire Protection Laboratory, Chemistry Division, National Institute of Standards, 136, Giza 12211 (Egypt)

    2015-11-15

    New and facile method for the synthesis and modification of magnesium hydroxide nanoparticles has been developed. The organic phosphate was used to facilitate the synthesis and wrapping of magnesium hydroxide nanoparticles with organic phosphate shell. The size of the nanoparticles wrapped with phosphate has an average diameter range from 46 to 125 nm. The preparation method has governed the nanoparticles diameter based on reaction time. Thermal stability and morphological properties of the new nanoparticles coated phosphates were investigated. The developed magnesium hydroxide nanoparticles-organic phosphate achieved a very good compatibility when dispersed in acrylonitrile-butadiene styrene polymer (ABS) produced dispersed nanocomposites. The flammability and thermal properties of the new polymer nanocomposites were studied. The rate of burning of the nanocomposites was reduced to 9.8 mm/min compared to 15, 21.9 and 42.5 mm/min for polymer-conventional magnesium hydroxide composite, polymer-conventional magnesium hydroxide-organic phosphate composite and virgin polymer, respectively. The peak heat release rate (PHRR) and total heat release (THR) of the new nanocomposites were recorded as 243.4 kW/m{sup 2} and 19.2 MJ/m{sup 2}, respectively, achieved 71% reduction for PHRR and 55% for THR. The synergism between magnesium hydroxide nanoparticles and organic phosphates shell was also studied. The developed nanoparticles suppressed the emission of toxic gases. The different materials were characterized using thermal gravimetric analysis, fourier transform infrared spectroscopy, transmission electron microscopy. The flammability properties were evaluated using UL94 horizontal method and cone calorimeter. The dispersion of magnesium hydroxide nanoparticles-organic phosphate in ABS was studied using scanning electron microscope. - Highlights: • Novel and facile nanoparticles synthesis and modification have developed. • Magnesium hydroxide nanoparticles size has

  9. Metal-organic framework templated synthesis of Fe{sub 2}O{sub 3}/TiO{sub 2} nanocomposite for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Krafft, Kathryn E. de; Wang, Cheng; Lin, Wenbin [University of North Carolina, Chapel Hill, NC (United States). Department of Chemistry

    2012-04-17

    A new metal-organic framework (MOF)-templated method has been developed for the synthesis of a metal oxide nanocomposite with interesting photophysical properties. Fe-containing nanoscale MOFs are coated with amorphous titania, then calcined to produce crystalline Fe{sub 2}O{sub 3}/TiO{sub 2} composite nanoparticles. This material enables photocatalytic hydrogen production from water using visible light, which cannot be achieved by either Fe{sub 2}O{sub 3} or TiO{sub 2} alone or a mixture of the two. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Cloning and expression analysis of 14 lipid transfer protein genes from Tamarix hispida responding to different abiotic stresses.

    Science.gov (United States)

    Wang, Chao; Yang, Chuanping; Gao, Caiqiu; Wang, Yucheng

    2009-12-01

    Plant lipid transfer proteins (LTPs) are ubiquitous lipid-binding proteins that are involved in various stress responses. In this study, we cloned 14 unique LTP genes (ThLTP 1-14) from Tamarix hispida Willd. (Tamaricaceae) to investigate their roles under various abiotic stress conditions. The expression profiles of the 14 ThLTPs in response to NaCl, polyethylene glycol (PEG), NaHCO(3), CdCl(2) and abscisic acid (ABA) exposure in root, stem and leaf tissues were investigated using real-time RT-PCR. The results showed that all 14 ThLTPs were expressed in root, stem and leaf tissues under normal growth conditions. However, under normal growth conditions, ThLTP abundance varied in each organ, with expression differences of 9000-fold in leaves, 540-fold in stems and 3700-fold in roots. These results indicated that activity and/or physiological importance of these ThLTPs are quite different. Differential expression of the 14 ThLTPs was observed (> 2-fold) for NaCl, PEG, NaHCO(3) and CdCl(2) in at least one tissue indicating that they were all involved in abiotic stress responses. All ThLTP genes were highly induced (> 2-fold) under ABA treatment in roots, stems and/or leaves, and particularly in roots, suggesting that ABA-dependent signaling pathways regulated ThLTPs. We hypothesize that ThLTP expression constitutes an adaptive response to abiotic stresses in T. hispida and plays an important role in abiotic stress tolerance.

  11. Overexpression of GmHsp90s, a heat shock protein 90 (Hsp90 gene family cloning from soybean, decrease damage of abiotic stresses in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Jinyan Xu

    Full Text Available Hsp90 is one of the most conserved and abundant molecular chaperones and is an essential component of the protective stress response; however, its roles in abiotic stress responses in soybean (Glycine max remain obscure. Here, 12 GmHsp90 genes from soybean were identified and found to be expressed and to function differentially under abiotic stresses. The 12 GmHsp90 genes were isolated and named GmHsp90A1-GmHsp90A6, GmHsp90B1, GmHsp90B2, GmHsp90C1.1, GmHsp90C1.2, GmHsp90C2.1 and GmHsp90C2.2 based on their characteristics and high homology to other Hsp90s according to a new nomenclature system. Quantitative real-time PCR expression data revealed that all the genes exhibited higher transcript levels in leaves and could be strongly induced under heat, osmotic and salt stress but not cold stress. Overexpression of five typical genes (GmHsp90A2, GmHsp90A4, GmHsp90B1, GmHsp90C1.1 and GmHsp90C2.1 in Arabidopsis thaliana provided useful evidences that GmHsp90 genes can decrease damage of abiotic stresses. In addition, an abnormal accumulation of proline was detected in some transgenic Arabidopsis plants suggested overexpressing GmHsp90s may affect the synthesis and response system of proline. Our work represents a systematic determination of soybean genes encoding Hsp90s, and provides useful evidence that GmHsp90 genes function differently in response to abiotic stresses and may affect the synthesis and response system of proline.

  12. Regulation of abiotic and biotic stress responses by plant hormones

    DEFF Research Database (Denmark)

    Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

    2016-01-01

    Plant hormones (phytohormones) are signal molecules produced within the plant, and occur in very low concentrations. In the present chapter, the current knowledge on the regulation of biotic and biotic stress responses by plant hormones is summarized with special focus on the novel insights...... into the complex hormonal crosstalk of classical growth stimulating plant hormones within the naturally occurring biotic and abiotic multistress environment of higher plants. The MAPK- and phytohormone-cascades which comprise a multitude of single molecules on different signalling levels, as well as interactions...

  13. Organizations

    DEFF Research Database (Denmark)

    Hatch, Mary Jo

    and considers many more. Mary Jo Hatch introduces the concept of organizations by presenting definitions and ideas drawn from the a variety of subject areas including the physical sciences, economics, sociology, psychology, anthropology, literature, and the visual and performing arts. Drawing on examples from......Most of us recognize that organizations are everywhere. You meet them on every street corner in the form of families and shops, study in them, work for them, buy from them, pay taxes to them. But have you given much thought to where they came from, what they are today, and what they might become...... prehistory and everyday life, from the animal kingdom as well as from business, government, and other formal organizations, Hatch provides a lively and thought provoking introduction to the process of organization....

  14. Comprehensive expression profiling of rice tetraspanin genes reveals diverse roles during development and abiotic stress

    Directory of Open Access Journals (Sweden)

    Balaji eM

    2015-12-01

    Full Text Available Tetraspanin family is comprised of evolutionarily conserved integral membrane proteins. The incredible ability of tetraspanins to form ‘micro domain complexes’ and their preferential targeting to membranes emphasizes their active association with signal recognition and communication with neighboring cells, thus acting as key modulators of signaling cascades. In animals, tetraspanins are associated with multitude of cellular processes. Unlike animals, the biological relevance of tetraspanins in plants has not been well investigated. In Arabidopsis tetraspanins are known to contribute in important plant development processes such as leaf morphogenesis, root and floral organ formation. In the present study we investigated the genomic organization, chromosomal distribution, phylogeny and domain structure of 15 rice tetraspanin proteins (OsTETs. OsTET proteins had similar domain structure and signature ‘GCCK/R’ motif as reported in Arabidopsis. Comprehensive expression profiling of OsTET genes suggested their possible involvement during rice development. While OsTET9 and 10 accumulated predominantly in flowers, OsTET5, 8 and 12 were preferentially expressed in root tissues. Noticeably, seven OsTETs exhibited more than 2-fold up regulation at early stages of flag leaf senescence in rice. Furthermore, several OsTETs were differentially regulated in rice seedlings exposed to abiotic stresses, exogenous treatment of hormones and nutrient deprivation. Transient subcellular localization studies of eight OsTET proteins in tobacco epidermal cells showed that these proteins localized in plasma membrane. The present study provides valuable insights into the possible roles of tetraspanins in regulating development and defining response to abiotic stresses in rice. Targeted proteomic studies would be useful in identification of their interacting partners under different conditions and ultimately their biological function in plants

  15. Mass Spectrometry in Organic Synthesis: Claisen-Schmidt Base-Catalyzed Condensation and Hammett Correlation of Substituent Effects

    Science.gov (United States)

    Bain, Ryan M.; Pulliam, Christopher J.; Yan, Xin; Moore, Kassandra F.; Mu¨ller, Thomas; Cooks, R. Graham

    2014-01-01

    Undergraduate laboratories generally teach an understanding of chemical reactivity using bulk or semimicroscale experiments with product isolation and subsequent chemical and spectroscopic analysis. In this study students were exposed to mass spectrometry as a means of chemical synthesis as well as analysis. The ionization method used, paper…

  16. Pig Liver Esterase (PLE) as Biocatalyst in Organic Synthesis: From Nature to Cloning and to Practical Applications

    NARCIS (Netherlands)

    Dominguez de Maria, Pablo; Garcia-Burgos, Carlos A.; Bargeman, Gerrald; van Gemert, Robert W.

    2007-01-01

    Pig liver esterase (PLE, EC 3.1.1.1) has been employed extensively for research purposes during the last three decades, especially in kinetic resolutions, in desymmetrizations of prochiral substrates, and in the synthesis of nucleosides. Its practical use, however, has been traditionally hampered

  17. Organ-Specific Alterations in Fatty Acid De Novo Synthesis and Desaturation in a Rat Model of Programmed Obesity

    Directory of Open Access Journals (Sweden)

    Desai Mina

    2011-05-01

    Full Text Available Abstract Background Small for gestational age (SGA leads to increased risk of adult obesity and metabolic syndrome. Offspring exposed to 50% maternal food restriction in utero are born smaller than Controls (FR, catch-up in growth by the end of the nursing period, and become obese adults. The objective of the study was to determine stearoyl-CoA desaturase activity (SCD1 and rates of de novo fatty acid synthesis in young FR and Control offspring tissues at the end of the nursing period, as possible contributors to catch-up growth. Methods From gestational day 10 to term, dams fed ad libitum (Control or were 50% food-restricted to produce small FR pups. Control dams nursed all pups. At postnatal day 1 (p1 and p21, offspring body tissues were analyzed by GC/MS, and desaturation indices of palmitoleate/palmitate and oleate/stearate were calculated. SCD1 gene expression was determined by real-time PCR on adipose and liver. Offspring were enriched with deuterium that was given to dams in drinking water during lactation and de novo synthesis of offspring body tissues was determined at p21. Primary adipocyte cell cultures were established at p21 and exposed to U13C-glucose. Results FR offspring exhibited higher desaturation index in p1 and p21 adipose tissue, but decreased desaturation index in liver at p21. SCD1 gene expression at p21 was correspondingly increased in adipose and decreased in liver. FR subcutaneous fat demonstrated increased de novo synthesis at p21. Primary cell cultures exhibited increased de novo synthesis in FR. Conclusions Adipose tissue is the first site to exhibit increased de novo synthesis and desaturase activity in FR. Therefore, abnormal lipogenesis is already present prior to onset of obesity during the period of catch-up growth. These abnormalities may contribute to future obesity development.

  18. Hydroxylated PCBs in abiotic environmental matrices. Precipitation and surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Darling, C.; Alaee, M.; Campbell, L.; Pacepavicius, G.; Ueno, D.; Muir, D. [National Water Research Institute, Burlington, ON (Canada)

    2004-09-15

    Hydroxylated PCBs (OH-PCBs) are of great interest environmentally because of their potential thyroidogenic effects. OH-PCBs can compete with thyroxine for binding sites on transthyretin, one of the three main thyroid hormone transport proteins in mammals1. The chemical structures of some OH-PCBs with a para OH group and adjacent chlorine atoms, particularly 4-OH-CB109, 4- OH-CB146, and 4-OH-CB187, share a similar structure to the thyroid hormones (T3 and T4), which have a para OH with adjacent iodine atoms. A number of OH-PCBs have been identified in the blood of humans and biota during the last 5 to 10 years, however, reports on the identity, presence and levels of OH-PCBs are limited. This presentation describes preliminary studies on the presence of OH-PCBs in abiotic samples and comparisons of congener patterns with biological samples. We have previously shown that OHPCBs were present in lake trout from the Great Lakes and nearby large lakes as well as in nearshore environments. We hypothesized that some of the OH-PCB present in fish might be from abiotic formation in water or the atmosphere, or from microbial oxidation of PCBs and/or deconjugation of PCB metabolites in waste treatment plants.

  19. Progress and challenges for abiotic stress proteomics of crop plants.

    Science.gov (United States)

    Barkla, Bronwyn J; Vera-Estrella, Rosario; Pantoja, Omar

    2013-06-01

    Plants are continually challenged to recognize and respond to adverse changes in their environment to avoid detrimental effects on growth and development. Understanding the mechanisms that crop plants employ to resist and tolerate abiotic stress is of considerable interest for designing agriculture breeding strategies to ensure sustainable productivity. The application of proteomics technologies to advance our knowledge in crop plant abiotic stress tolerance has increased dramatically in the past few years as evidenced by the large amount of publications in this area. This is attributed to advances in various technology platforms associated with MS-based techniques as well as the accessibility of proteomics units to a wider plant research community. This review summarizes the work which has been reported for major crop plants and evaluates the findings in context of the approaches that are widely employed with the aim to encourage broadening the strategies used to increase coverage of the proteome. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Regulation of Translation Initiation under Biotic and Abiotic Stresses

    Directory of Open Access Journals (Sweden)

    Ana B. Castro-Sanz

    2013-02-01

    Full Text Available Plants have developed versatile strategies to deal with the great variety of challenging conditions they are exposed to. Among them, the regulation of translation is a common target to finely modulate gene expression both under biotic and abiotic stress situations. Upon environmental challenges, translation is regulated to reduce the consumption of energy and to selectively synthesize proteins involved in the proper establishment of the tolerance response. In the case of viral infections, the situation is more complex, as viruses have evolved unconventional mechanisms to regulate translation in order to ensure the production of the viral encoded proteins using the plant machinery. Although the final purpose is different, in some cases, both plants and viruses share common mechanisms to modulate translation. In others, the mechanisms leading to the control of translation are viral- or stress-specific. In this paper, we review the different mechanisms involved in the regulation of translation initiation under virus infection and under environmental stress in plants. In addition, we describe the main features within the viral RNAs and the cellular mRNAs that promote their selective translation in plants undergoing biotic and abiotic stress situations.

  1. Herboxidiene triggers splicing repression and abiotic stress responses in plants

    KAUST Repository

    Alshareef, Sahar

    2017-03-27

    Background Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and stresses. Small-molecule inhibitors that perturb splicing provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Results Here, we show that herboxidiene (GEX1A) inhibits both constitutive and alternative splicing. Moreover, GEX1A activates genome-wide transcriptional patterns involved in abiotic stress responses in plants. GEX1A treatment -activated ABA-inducible promoters, and led to stomatal closure. Interestingly, GEX1A and pladienolide B (PB) elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. Conclusions Our study establishes GEX1A as a potent splicing inhibitor in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

  2. Paper-Based Heavy Metal Sensors from the Concise Synthesis of an Anionic Porphyrin: A Practical Application of Organic Synthesis to Environmental Chemistry

    Science.gov (United States)

    Prabpal, Jutamat; Vilaivan, Tirayut; Praneenararat, Thanit

    2017-01-01

    Tetrakis(4-sulfonatophenyl)porphyrin (TSPP) was immobilized on patterned paper and used as a sensor for heavy metal ions in an advanced organic chemistry course. The resulting sensor could detect Hg[superscript 2+] and Cd[superscript 2+] ions colorimetrically, while Cu[superscript 2+] ion resulted in fluorescence quenching, thus demonstrating a…

  3. Induction of metallothionein(s) in organ-cultured duodenum: relationship to 1α,25-(OH)2-D3-induced CaBP synthesis

    International Nuclear Information System (INIS)

    Corradino, R.A.; Fullmer, C.S.; Frelier, E.; Maxwell, S.

    1979-01-01

    The embryonic chick duodenum contains no vitamin D-induced, calcium-binding protein (CaBP). However, when maintained in organ culture, the duodenum responds to 1α,25-(OH) 2 -D 3 in the culture medium by de novo synthesis of CaBP. Studies with this system have provided evidence that CaBP is directly involved in calcium transport at least at the mucosal surface. The present paper extends previous observations on the effects of the extremely toxic environmental pollutant, cadmium. Cadmium was found to inhibit 1α,25-(OH) 2 -D 3 -mediated responses in the organ-cultured duodenum, i.e., CaBP biosynthesis and 45 Ca uptake at the mucosal surface. Cadmium also stimulated concomitent production of a specific metallothionein (MT). Zinc had similar actions in inhibiting CaBP and stimulating Mt biosynthesis

  4. A rapid microwave-assisted synthesis of a sodium-cadmium metal-organic framework having improved performance as a CO2 adsorbent for CCS.

    Science.gov (United States)

    Palomino Cabello, Carlos; Arean, Carlos Otero; Parra, José B; Ania, Conchi O; Rumori, P; Turnes Palomino, G

    2015-06-07

    We report on a facile and rapid microwave-assisted method for preparing a sodium-cadmium metal-organic framework (having coordinatively unsaturated sodium ions) that considerably shortens the conventional synthesis time from 5 days to 1 hour. The obtained (Na,Cd)-MOF showed an excellent volumetric CO2 adsorption capacity (5.2 mmol cm(-3) at 298 K and 1 bar) and better CO2 adsorption properties than those shown by the same metal-organic framework when synthesized following a more conventional procedure. Moreover, the newly prepared material was found to display high selectivity for adsorption of carbon dioxide over nitrogen, and good regenerability and stability during repeated CO2 adsorption-desorption cycles, which are the required properties for any adsorbent intended for carbon dioxide capture and sequestration (CSS) from the post-combustion flue gas of fossil fuelled power stations.

  5. Design and synthesis of a water-stable anionic uranium-based metal-organic framework (MOF) with ultra large pores

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng; Vermeulen, Nicolaas A.; Gong, Xirui; Malliakas, Christos D.; Stoddart, J. Fraser; Hupp, Joseph T. [Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Farha, Omar K. [Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; King Abdulaziz Univ., Jeddah (Saudi Arabia). Dept. of Chemistry

    2016-08-22

    Ionic metal-organic frameworks (MOFs) are a subclass of porous materials that have the ability to incorporate different charged species in confined nanospace by ion-exchange. To date, however, very few examples combining mesoporosity and water stability have been realized in ionic MOF chemistry. Herein, we report the rational design and synthesis of a water-stable anionic mesoporous MOF based on uranium and featuring tbo-type topology. The resulting tbo MOF exhibits exceptionally large open cavities (3.9 nm) exceeding those of all known anionic MOFs. By supercritical CO{sub 2} activation, a record-high Brunauer-Emmett-Teller (BET) surface area (2100 m{sup 2} g{sup -1}) for actinide-based MOFs has been obtained. Most importantly, however, this new uranium-based MOF is water-stable and able to absorb positively charged ions selectively over negatively charged ones, enabling the efficient separation of organic dyes and biomolecules.

  6. Differential expression of poplar sucrose nonfermenting1-related protein kinase 2 genes in response to abiotic stress and abscisic acid.

    Science.gov (United States)

    Yu, Xiang; Takebayashi, Arika; Demura, Taku; Ohtani, Misato

    2017-09-01

    Knowledge on the responses of woody plants to abiotic stress can inform strategies to breed improved tree varieties and to manage tree species for environmental conservation and the production of lignocellulosic biomass. In this study, we examined the expression patterns of poplar (Populus trichocarpa) genes encoding members of the sucrose nonfermenting1-related protein kinase 2 (SnRK2) family, which are core components of the abiotic stress response. The P. trichocarpa genome contains twelve SnRK2 genes (PtSnRK2.1- PtSnRK2.12) that can be divided into three subclasses (I-III) based on the structures of their encoded kinase domains. We found that PtSnRK2s are differentially expressed in various organs. In MS medium-grown plants, all of the PtSnRK2 genes were significantly upregulated in response to abscisic acid (ABA) treatment, whereas osmotic and salt stress treatments induced only some (four and seven, respectively) of the PtSnRK2 genes. By contrast, soil-grown plants showed increased expression of most PtSnRK2 genes under drought and salt treatments, but not under ABA treatment. In soil-grown plants, drought stress induced SnRK2 subclass II genes in all tested organs (leaves, stems, and roots), whereas subclass III genes tended to be upregulated in leaves only. These results suggest that the PtSnRK2 genes are involved in abiotic stress responses, are at least partially activated by ABA, and show organ-specific responses.

  7. Effect of organic materials used in the synthesis on the emission from CdSe quantum dots

    Science.gov (United States)

    Lee, Jae-Won; Yang, Ho-Soon; Hong, K. S.; Kim, S. M.

    2013-12-01

    Quantum-dot nanocrystals have particular optical properties due to the quantum confinement effect and the surface effect. This study focuses on the effect of surface conditions on the emission from quantum dots. The quantum dots prepared with 1-hexadecylamine (HDA) in the synthesis show strong emission while the quantum dots prepared without HDA show weak emission, as well as emission from surface energy traps. The comparison of the X-ray patterns of these two sets of quantum dots reveals that HDA forms a layer on the surface of quantum dot during the synthesis. This surface passivation with a layer of HDA reduces surface energy traps, therefore the emission from surface trap levels is suppressed in the quantum dots synthesized with HDA.

  8. Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules - An inventory for the origins of life

    Science.gov (United States)

    Chyba, Christopher; Sagan, Carl

    1992-01-01

    The contribution of organic-rich comets, carbonaceous asteroids, and interplanetary dust particles and of impact shock-synthesized organics in the atmosphere to the origin of life on earth is studied and quantitatively compared with the principal non-heavy-bombardment sources of prebiotic organics. The results suggest that heavy bombardment before 3.5 Gyr ago either produced or delivered quantities of organics comparable to those produced by other energy sources.

  9. Exploring biotic vs. abiotic controls on syngenetic carbonate and clay mineral precipitation

    Science.gov (United States)

    Nascimento, Gabriela S.; McKenzie, Judith A.; Martinez Ruiz, Francisca; Bontognali, Tomaso R. R.; Vasconcelos, Crisogono

    2016-04-01

    A possible syngenetic relationship between carbonate and clay mineral precipitation has been reported for sedimentary rocks deposited in both lacustrine and marine sedimentary environments throughout the geological record. In particular, the mineral dolomite is often found associated with Mg-rich clays, such as stevensite. It is notable that this carbonate/clay association has been recorded in numerous samples taken from modern dolomite precipitating environments; for example, the Coorong lakes, South Australia, coastal sabkhas, Abu Dhabi, UAE and coastal hypersaline lagoons (Lagoa Vermelha and Brejo do Espinho) east of Rio de Janeiro, Brazil. An HRTEM study of samples from these three locations indicates a possible physical/chemical association between the Ca-dolomite and Mg-rich clays, demonstrating a probable co-precipitation. To test this hypothesis, we have conducted a series of biotic and abiotic laboratory experiments. If this syngenesis actually occurs in nature, what, if any, are the biogeochemical processes controlling these precipitation reactions? Our experiments were designed to determine the extent of the biotic versus abiotic component influencing the mineral precipitation and, in the case of a biotic influence, to understand the mechanism through which microorganisms might mediate the formation of clay minerals. The experiments were carried out in the Geomicrobiology Laboratory of ETH Zürich using cultures of living microbes and artificial organic compounds that simulate functional groups present in natural biofilms formed under both aerobic and anaerobic conditions. In addition, pure inorganic experiments were designed to understand possible physico-chemical conditions for diagenetic processes that could induce dissolution of Mg-carbonates and precipitation of Mg-rich clays. Our results show a remarkable biotic influence during the formation of clay minerals. Specifically, extracellular polymeric substances (EPS), released by microbes in their

  10. The Role of Template Structure and Synergism between Inorganic and Organic Structure Directing Agents in the Synthesis of UTL Zeolite

    Czech Academy of Sciences Publication Activity Database

    Shvets, O. V.; Kasian, N.; Zukal, Arnošt; Pinkas, Jiří; Čejka, Jiří

    2010-01-01

    Roč. 22, č. 11 (2010), s. 3482-3495 ISSN 0897-4756 R&D Projects: GA ČR GA203/08/0604; GA ČR GA104/07/0383 Institutional research plan: CEZ:AV0Z40400503 Keywords : UTL zeolite * synthesis * zeolite molecular sietes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 6.400, year: 2010

  11. Highly effective synthesis of a cobalt(ii) metal-organic coordination polymer by using continuous flow chemistry.

    Science.gov (United States)

    Gong, Chunhua; Zhang, Junyong; Zeng, Xianghua; Xie, Jingli

    2016-12-20

    The coordination polymer [Co 2 L 4 (H 2 O) 2 ]·CH 3 CN·H 2 O (HL = (E)-2-[2-(4-chlorophenyl)vinyl]-8-hydroxyquinoline) has been achieved with 95% yield by using an Asia flow synthesis system (chip reactor). Compared with the conventional batch-type methods such as diffusion, reflux and solvothermal reactions, higher yielding reactions carried out in a flow reactor have demonstrated that this technique is a powerful strategy to obtain coordination compounds.

  12. Solvent-Free Synthesis of 2,20'-Dinitrobiphenyl: An Ullmann Coupling in the Introductory Organic Laboratory

    Science.gov (United States)

    Gregor, Richard W.; Goj, Laurel A.

    2011-01-01

    The formation of carbon-carbon bonds is an essential theme throughout organic chemistry. The use of transition-metal catalysts to form carbon-carbon bonds, once relegated to more advanced texts, is now commonly found in introductory organic textbooks. However, commensurate laboratory experiments for first-year organic students are more limited.…

  13. A phenomics approach to the analysis of the influence of glutathione on leaf area and abiotic stress tolerance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Daniel eSchnaubelt

    2013-11-01

    Full Text Available Reduced glutathione (GSH is an abundant low molecular weight plant thiol. It fulfils multiple functions in plant biology, many of which remain poorly characterised. A phenomics approach was therefore used to investigate the effects of glutathione homeostasis on growth and stress tolerance in Arabidopsis thaliana. Rosette leaf area was compared in mutants that are either defective in GSH synthesis (cad2, pad2 and rax1 or the export of γ-glutamyl cysteine and GSH from the chloroplast (clt and in wild type plants under standard growth conditions and following exposure to a range of abiotic stress treatments, including oxidative stress, water stress and high salt. In the absence of stress, the GSH synthesis mutants had a significantly lower leaf area than the wild type. Conversely, the clt mutant has a greater leaf area and a significantly reduced lateral root density than the wild type. These findings demonstrate that cellular glutathione homeostasis exerts an influence on root architecture and on rosette area. An impaired capacity to synthesise GSH or a specific depletion of the cytosolic GSH pool did not adversely affect leaf area in plants exposed to short term abiotic stress. However, the negative effects of long term exposure to oxidative stress and high salt on leaf area were less marked in the GSH synthesis mutants than the wild type. These findings demonstrate the importance of cellular glutathione homeostasis in the regulation of plant growth under optimal and stress conditions.

  14. A phenomics approach to the analysis of the influence of glutathione on leaf area and abiotic stress tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Schnaubelt, Daniel; Schulz, Philipp; Hannah, Matthew A; Yocgo, Rosita E; Foyer, Christine H

    2013-01-01

    Reduced glutathione (GSH) is an abundant low molecular weight plant thiol. It fulfills multiple functions in plant biology, many of which remain poorly characterized. A phenomics approach was therefore used to investigate the effects of glutathione homeostasis on growth and stress tolerance in Arabidopsis thaliana. Rosette leaf area was compared in mutants that are either defective in GSH synthesis (cad2, pad2, and rax1) or the export of γ-glutamylcysteine and GSH from the chloroplast (clt) and in wild-type plants under standard growth conditions and following exposure to a range of abiotic stress treatments, including oxidative stress, water stress, and high salt. In the absence of stress, the GSH synthesis mutants had a significantly lower leaf area than the wild type. Conversely, the clt mutant has a greater leaf area and a significantly reduced lateral root density than the wild type. These findings demonstrate that cellular glutathione homeostasis exerts an influence on root architecture and on rosette area. An impaired capacity to synthesize GSH or a specific depletion of the cytosolic GSH pool did not adversely affect leaf area in plants exposed to short-term abiotic stress. However, the negative effects of long-term exposure to oxidative stress and high salt on leaf area were less marked in the GSH synthesis mutants than the wild type. These findings demonstrate the importance of cellular glutathione homeostasis in the regulation of plant growth under optimal and stress conditions.

  15. Fe(II-III) Hydroxysalt Green Rusts; from Corrosion to Mineralogy and Abiotic to Biotic Reactions by Moessbauer Spectroscopy

    International Nuclear Information System (INIS)

    Genin, J.-M. R.

    2004-01-01

    Fe(II)-Fe(III) hydroxysalts commonly called green rusts are layered double hydroxides of formula [Fe II (1-x) Fe III x (OH) 2 ] x+ .[(x/n)A n- .(m/n)H 2 O] x- constituted of brucite-like layers containing Fe cations in the centres of OH - octahedrons and interlayers, which anions and water molecules belong to. They play a key role in corrosion and environmental sciences as well as mineralogy since they are, on the one hand, intermediate products between Fe(II) and Fe(III) states and, on the other hand, can be the major iron-bearing mineral in hydromorphic gley soils. Their crystal structure, Moessbauer spectra, methods of synthesis, abiotic as well as biotic, and some applications are presented here.

  16. Abiotic nitrate reduction in the presence of steel material and hydrogen in cementitious environments

    International Nuclear Information System (INIS)

    Truche, L.; Berger, G.; Albrecht, A.

    2012-01-01

    Document available in extended abstract form only. Abiotic nitrate reduction induced by different electron donors represents a major reaction of interest in the context of disposal of nuclear waste containing such oxyanions (Honda et al., 2006; Katsounaros et al., 2009). These wastes are characterized, amongst others by the coexistence of oxyanions (nitrate, phosphate, sulfate...) and potentially reducing agents such as organic matter, native metals and hydrogen gas formed or from package material via radiolysis or anaerobic corrosion. In addition to the large number of reactants present in the waste itself, the medium-level long-lived (MAVL) waste concept is based on large masses of concrete and steel in part used for primary waste containers as well as armored cement over pack and engineered barrier; a concept that guarantees the mechanical stability of both the waste container and the waste cell. In this experimental study we evaluate the consequences of steel material (carbon steel and 316L stainless steel) from waste canisters and construction material (concrete and Callovo- Oxfordian argillite), as well as magnetite as their possible corrosion by-products, on the reduction of aqueous nitrate in the presence of hydrogen. A parametric study (0 2 ) - ] 2+ , Fe 2+ ) that can act as electron donors. This experimental study demonstrates that abiotic nitrate reduction induced by the combination of steel materials and hydrogen is a likely process under waste cell conditions, thus applicable to cases where nitrate-bearing waste (i.e. nuclear) is disposed in near-surface or in deep geological settings. Depending on the nature of the steel, the reaction may exhibit different kinetic features that would require dedicated assessment. An increase in nitrate concentrat ions above the steel saturation level of 10 mM (Fig. 1; beyond the range of the current study) may also have an influence on reaction processes and kinetics and thus influence nitrate reactivity. (authors)

  17. Characterization of a eukaryotic translation initiation factor 5A homolog from Tamarix androssowii involved in plant abiotic stress tolerance

    Directory of Open Access Journals (Sweden)

    Wang Liuqiang

    2012-07-01

    Full Text Available Abstract Background The eukaryotic translation initiation factor 5A (eIF5A promotes formation of the first peptide bond at the onset of protein synthesis. However, the function of eIF5A in plants is not well understood. Results In this study, we characterized the function of eIF5A (TaeIF5A1 from Tamarix androssowii. The promoter of TaeIF5A1 with 1,486 bp in length was isolated, and the cis-elements in the promoter were identified. A WRKY (TaWRKY and RAV (TaRAV protein can specifically bind to a W-box motif in the promoter of TaeIF5A1 and activate the expression of TaeIF5A1. Furthermore, TaeIF5A1, TaWRKY and TaRAV share very similar expression pattern and are all stress-responsive gene that functions in the abscisic acid (ABA signaling pathway, indicating that they are components of a single regulatory pathway. Transgenic yeast and poplar expressing TaeIF5A1 showed elevated protein levels combined with improved abiotic stresses tolerance. Furthermore, TaeIF5A1-transformed plants exhibited enhanced superoxide dismutase (SOD and peroxidase (POD activities, lower electrolyte leakage and higher chlorophyll content under salt stress. Conclusions These results suggested that TaeIF5A1 is involved in abiotic stress tolerance, and is likely regulated by transcription factors TaWRKY and TaRAV both of which can bind to the W-box motif. In addition, TaeIF5A1 may mediate stress tolerance by increasing protein synthesis, enhancing ROS scavenging by improving SOD and POD activities, and preventing chlorophyll loss and membrane damage. Therefore, eIF5A may play an important role in plant adaptation to changing environmental conditions.

  18. Characterization of a eukaryotic translation initiation factor 5A homolog from Tamarix androssowii involved in plant abiotic stress tolerance.

    Science.gov (United States)

    Wang, Liuqiang; Xu, Chenxi; Wang, Chao; Wang, Yucheng

    2012-07-26

    The eukaryotic translation initiation factor 5A (eIF5A) promotes formation of the first peptide bond at the onset of protein synthesis. However, the function of eIF5A in plants is not well understood. In this study, we characterized the function of eIF5A (TaeIF5A1) from Tamarix androssowii. The promoter of TaeIF5A1 with 1,486 bp in length was isolated, and the cis-elements in the promoter were identified. A WRKY (TaWRKY) and RAV (TaRAV) protein can specifically bind to a W-box motif in the promoter of TaeIF5A1 and activate the expression of TaeIF5A1. Furthermore, TaeIF5A1, TaWRKY and TaRAV share very similar expression pattern and are all stress-responsive gene that functions in the abscisic acid (ABA) signaling pathway, indicating that they are components of a single regulatory pathway. Transgenic yeast and poplar expressing TaeIF5A1 showed elevated protein levels combined with improved abiotic stresses tolerance. Furthermore, TaeIF5A1-transformed plants exhibited enhanced superoxide dismutase (SOD) and peroxidase (POD) activities, lower electrolyte leakage and higher chlorophyll content under salt stress. These results suggested that TaeIF5A1 is involved in abiotic stress tolerance, and is likely regulated by transcription factors TaWRKY and TaRAV both of which can bind to the W-box motif. In addition, TaeIF5A1 may mediate stress tolerance by increasing protein synthesis, enhancing ROS scavenging by improving SOD and POD activities, and preventing chlorophyll loss and membrane damage. Therefore, eIF5A may play an important role in plant adaptation to changing environmental conditions.

  19. Comparative physiological, metabolomic, and transcriptomic analyses reveal mechanisms of improved abiotic stress resistance in bermudagrass [Cynodon dactylon (L). Pers.] by exogenous melatonin

    Science.gov (United States)

    Shi, Haitao; Jiang, Chuan; Ye, Tiantian; Tan, Dun-xian; Reiter, Russel J.; Zhang, Heng; Liu, Renyi; Chan, Zhulong

    2015-01-01

    Melatonin (N-acetyl-5-methoxytryptamine), a well-known animal hormone, is also involved in plant development and abiotic stress responses. In this study, it is shown that exogenous application of melatonin conferred improved salt, drought, and cold stress resistances in bermudagrass. Moreover, exogenous melatonin treatment alleviated reactive oxygen species (ROS) burst and cell damage induced by abiotic stress; this involved activation of several antioxidants. Additionally, melatonin-pre-treated plants exhibited higher concentrations of 54 metabolites, including amino acids, organic acids, sugars, and sugar alcohols, than non-treated plants under abiotic stress conditions. Genome-wide transcriptomic profiling identified 3933 transcripts (2361 up-regulated and 1572 down-regulated) that were differentially expressed in melatonin-treated plants versus controls. Pathway and gene ontology (GO) term enrichment analyses revealed that genes involved in nitrogen metabolism, major carbohydrate metabolism, tricarboxylic acid (TCA)/org transformation, transport, hormone metabolism, metal handling, redox, and secondary metabolism were over-represented after melatonin pre-treatment. Taken together, this study provides the first evidence of the protective roles of exogenous melatonin in the bermudagrass response to abiotic stresses, partially via activation of antioxidants and modulation of metabolic homeostasis. Notably, metabolic and transcriptomic analyses showed that the underlying mechanisms of melatonin could involve major reorientation of photorespiratory and carbohydrate and nitrogen metabolism. PMID:25225478

  20. Comparative physiological, metabolomic, and transcriptomic analyses reveal mechanisms of improved abiotic stress resistance in bermudagrass [Cynodon dactylon (L). Pers.] by exogenous melatonin.

    Science.gov (United States)

    Shi, Haitao; Jiang, Chuan; Ye, Tiantian; Tan, Dun-Xian; Reiter, Russel J; Zhang, Heng; Liu, Renyi; Chan, Zhulong

    2015-02-01

    Melatonin (N-acetyl-5-methoxytryptamine), a well-known animal hormone, is also involved in plant development and abiotic stress responses. In this study, it is shown that exogenous application of melatonin conferred improved salt, drought, and cold stress resistances in bermudagrass. Moreover, exogenous melatonin treatment alleviated reactive oxygen species (ROS) burst and cell damage induced by abiotic stress; this involved activation of several antioxidants. Additionally, melatonin-pre-treated plants exhibited higher concentrations of 54 metabolites, including amino acids, organic acids, sugars, and sugar alcohols, than non-treated plants under abiotic stress conditions. Genome-wide transcriptomic profiling identified 3933 transcripts (2361 up-regulated and 1572 down-regulated) that were differentially expressed in melatonin-treated plants versus controls. Pathway and gene ontology (GO) term enrichment analyses revealed that genes involved in nitrogen metabolism, major carbohydrate metabolism, tricarboxylic acid (TCA)/org transformation, transport, hormone metabolism, metal handling, redox, and secondary metabolism were over-represented after melatonin pre-treatment. Taken together, this study provides the first evidence of the protective roles of exogenous melatonin in the bermudagrass response to abiotic stresses, partially via activation of antioxidants and modulation of metabolic homeostasis. Notably, metabolic and transcriptomic analyses showed that the underlying mechanisms of melatonin could involve major reorientation of photorespiratory and carbohydrate and nitrogen metabolism. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.