57 research outputs found

    Neogene Uplift and Magmatism of Anatolia: Insights from Drainage Analysis and Basaltic Geochemistry

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    It is generally agreed that mantle dynamics have played a significant role in generating and maintaining the elevated topography of Anatolia during Neogene times. However, there is much debate about the relative importance of subduction zone and asthenospheric processes. Key issues concern onset and cause of regional uplift, thickness of the lithospheric plate, and the presence or absence of temperature and/or compositional anomalies within the convecting mantle. Here, we tackle these interlinked issues by analyzing and modeling two disparate suites of observations. First, a drainage inventory of 1,844 longitudinal river profiles is assembled. This geomorphic database is inverted to calculate the variation of Neogene regional uplift through time and space by minimizing the misfit between observed and calculated river profiles subject to independent calibration. Our results suggest that regional uplift commenced in the east at 20 Ma and propagated westward. Secondly, we have assembled a database of geochemical analyses of basaltic rocks. Two different approaches have been used to quantitatively model this database with a view to determining the depth and degree of asthenospheric melting across Anatolia. Our results suggest that melting occurs at depths as shallow as 60 km in the presence of mantle potential temperatures as high as 1400°C. There is evidence that potential temperatures are higher in the east, consistent with the pattern of sub-plate shear wave velocity anomalies. Our combined results are consistent with isostatic and admittance analyses and suggest that elevated asthenospheric temperatures beneath thinned Anatolian lithosphere have played a first order role in generating and maintaining regional dynamic topography and basaltic magmatism

    Synthesis of methyl (E)-2?,4?-thiazachalcones and their N-alkyl derivatives, photochemistry with theoretical calculations and antimicrobial activities

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    A series of 9 new (E) -thiazachalcones (1-3), and their N -alkyl substituted derivatives (4-6), and stereoselective dimerization products (7-9) were synthesized, then tested for antimicrobial activity against all test microorganisms except Pseudomonas aeruginosa. The new compounds (1-6) without dimerization products (7-9) showed good antimicrobial property against Staphylococcus aureus, Listeria monocitogenes, and Enterococcus faecalis. The possible dimerization products of compounds (1-3) were calculated theoretically. Experimental and theoretical calculation showed that ? -truxinic type dimer is the most stable isomer. © TÜBİTAK

    Chemical constituents and antimicrobial activity of the essential oil from vicia dadianorum extracted by hydro and microwave distillations

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    The aim of this research was to investigate the influence of extraction methods on yield and chemical composition of the essential oil of Vicia dadianorum Somm. & Lev. The volatiles of V. dadianorum have been isolated by hydro and microwave distillations (HD and MD). The compositions of the essential oils were characterized by GC-FID and GC-MS. A total of seventy-six and fifty-six compounds were identified, constituting over 90.9%, and 80.1% of oil composition of V. dadianorum, respectively. Sesquiterpene hydrocarbons were shown to be the main group of volatiles (HD: 26.2% and MD: 15.9%). The major terpene constituent of the essential oils of V. dadianorum was ?-elemene (HD, 13.7% and MD, 8.4%). Comparative study showed that the amount of total volatiles (90.9%) and the major constituent (26.2%) were found to be better in HD of V. dadianorum. The antimicrobial activity of the isolated essential oils of the plant was also investigated, and it showed moderate antimicrobial and antifungal activities against Staphylococcus aureus, Enterococcus faecalis, Bacillus cereus, Mycobacterium smegmatis and Candida albicans

    Composition and antimicrobial activity of the essential oils from flowers of Senecio othonnae, S. racemosus, and S. nemorensis

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    PubMed: 20521557The chemical composition of the essential oils of Senecio othonnae, S. racemosus, and S. nemorensis obtained by hydrodistillation of fresh flowers were analysed by GC-FID and GC-MS. A total of seventy-six compounds were identified, constituting over 83.1%, 97.7% and 86.8% of the total oil composition of the flowers of S. othonnae, S. racemosus, and S. nemorensis. The main components of the oils were caryophyllene oxide (18.6%), (E)-?-farnesene (21.6%), and ?-curcumene (42.8%), respectively. Sesquiterpene hydrocarbons were the main group of constituents of all three species, forming 34.6%, 73.2%, and 81.8% of the oils, respectively. The oils of S. othonnae, and S. nemorensis showed antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, and Candida tropicalis, but that of S. racemosus was only active against Candida tropicalis

    Chemical composition and antimicrobial activity of the essential oils from the flower, leaf, and stem of Senecio pandurifolius

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    The essential oils from the fresh flower, leaf, and stem of Senecio pandurifolius (Asteraceae) were isolated by hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. A total of forty-five, sixty, and forty-two compounds were identified, constituting over 90.1%, 88.0%, and 89.0% of oil composition of the flower, leaf, and stem of S. pandurifolius, respectively. The chemical profile reveals the dominance of sesquiterpene hydrocarbons (flower: 42.4%, leaf: 43.4%, stem: 52.3%). The main components of essential oils own to S. pandurifolius were ?-cuprenene (30.7%) in flower, ?-zingiberene (16.1%) in leaf and ?- curcumene (14.9%) in stem. Terpene related compounds were in minor amounts in all parts (flower: 1.4%, leaf: 1.5%, stem: 1.9%) of the S. pandurifolius. Also there was no monoterpene hydrocarbons and oxygenated monoterpenes in the essential oil of the stem. In addition, antimicrobial activities of the essential oils of S. pandurifolius were investigated. The oils showed activity against Gram positive bacteria, mycobacterium and fungi, but not Gram negative bacteria. A high antimycobacterial activity was observed with leaf essential oil, which deserves further investigation to determine its active components. © 2011 Reproduction is free for scientific studies

    Lactobacillus

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    Antimicrobial activity and a comparative essential oil analysis of Centaurea pulcherrima Willd. var. pulcherrima extracted by hydrodistillation and microwave distillation

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    PubMed: 21902569The essential oils of Centaurea pulcherrima Willd. var. pulcherrima (Asteraceae) were isolated by hydrodistillation (HD) and a microwave distillation (MD), than characterised by GC-FID and GC-MS. A total of 58 and 57 compounds were identified, constituting over 93.7%, and 91.6% of volatile oil composition of C. pulcherrima var. pulcherrima, respectively. Sesquiterpene hydrocarbons were shown to be the main group of constituents (HD: 42.4% versus MD: 51.5%). The major component of the oils of C. pulcherrima var. pulcherrima was germacrene D (HD, 17.8% versus MD, 23.2%). The antimicrobial activity of the isolated essential oils of the plant was also investigated, and they showed good antibacterial activity against to tested Gram-positive bacteria, especially to M. smegmatis and a yeast-like fungus C. albicans. © 2011 Taylor & Francis.This work was supported by grants from Karadeniz Technical University Research Fund and State Planning Agency (DPT) of Turkey. We thank to Prof S. Terziog? lu for identification of the plant

    Synthesis and antimicrobial activity of methoxy azachalcones and N-Alkyl substituted methoxy azachalconium bromides

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    In this study, 18 new N-octyl, N-decyl, and N-dodecyl substituted o-, m-, and p-methoxy (E)-3-and 4-azachalcones, {4-or 3-[(1E)-3-(4-, 3-, or 2-methoxyphenyl)-3-oxoprop-1-en-1-yl]-1-alkyl (C8,10,12) pyridinium bromides} (1a-6a, 1b-1b, and 1c-6c), and 4 new o-, and m-methoxy (E)-3-and 4-azachalcones (2, 3, 5, and 6) were synthesized and tested for antimicrobial activities against Escherichia coli, Yersinia pseudotuberculosis, Enterobacter aerogenes, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Bacillus cereus, and Candida albicans. N-Alkyl substituted azachalconium bromides showed good antimicrobial activity against all tested microorganisms with minimal inhibitory concentration (MIC) values in the range of 0.42-58.7 ?g/mL in most cases. Nonalkylated compounds 1-9 were not as effective as the alkylated compounds. They showed only antimicrobial activity against gram-positive bacteria and yeast in the range of 1.77-123.7 ?g/mL. The optimum length of the alkyl chain for better activity is situated with 12 carbon atoms in the series of compounds 1a-c, 2a-c, 3a-c, 4a-c, 5a-c, and 6a-c. N-Alkyl derivatives of m-methoxy (E)-3-azachalcone (4a-c, 5a-c, and 6a-c) showed better activity in comparison to those of oand p-methoxy (E)-4-azachalcones (1a-c, 2a-c, and 3a-c). © TÜBİTAK

    Synthesis, configuration, and antimicrobial properties of novel substituted and cyclized '2?,3?-thiazachalcones'

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    Nine new thiazachalcone-based drugs, compounds 1-9, were prepared and fully characterized. The configurations of the photochemical-dimerization products 7-9 were rationalized by semi-empirical calculations. Both the experimental data and the theoretical calculations showed that the ?-truxinic acid type dimer is the most stable isomer of all. All compounds were tested for their antibacterial and antifungal activities. The N-alkylated congeners 4-6 showed strong antimicrobial activities against various bacteria and a yeast-like fungus. The MIC and MBC values were as low as 0.1 ?g/ml. All the compounds were active against the Gram-positive bacterium Staphylococcus aureus. © 2007 Verlag Helvetica Chimica Acta AG

    Chemical composition and antimicrobial activity of the essential oils from the aerial parts of Astragalus hamzaoglui extracted by hydrodistillation and microwave distillation

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    The essential oils from the areal parts (flower, leaf and stem) of Astragalus hamzaoglui were isolated by hydrodistillation (HD) and a microwave distillation (MD) process. The composition of the volatiles was analysed by GC-FID and GC-MS and screened for their in vitro antimicrobial activity. Totals of 68/64, 65/64, and 68/67 compounds were identified in the flower, leaf, and stem oils of A. hamzaoglui accounting for 92.9- 95.0% in HD and 87.4-90.7% in MD, respectively. The essential oils consisted mainly of oxygenated monoterpenes (flower, HD: 33.3% vs. MD: 2.3%, leaf, HD: 8.0% vs. MD: 2.7%, stem, HD: 10.8% vs. MD: 4.7%), alcohols (flower, HD: 13.6% vs. MD: 10.4%, leaf, HD: 51.6% vs. MD: 3.6%, stem, HD: 35.4% vs. MD: 7.6%) and aldehydes (flower, HD: 15.5% vs. MD: 27.9%, leaf, HD: 10.0% vs. MD: 14.8%, stem, HD: 17.2% vs. MD: 24.5%). The major component of the oils of A. hamzaoglui was 1-octene-3-ol (flower, HD: 11.3% vs. MD: 8.8%, leaf, HD: 45.50% vs. MD: 3.3%, stem, HD: 32.6% vs. MD: 6.9%). Oxygenated sesquiterpenes were the minor constituents in all parts (flower, HD: 0.8% vs. MD: 0.4%, leaf, HD: 0.2% vs. MD: 0.4%, stem, HD: 0.4% vs. MD: 0.4%). of the A. hamzaoglui. Comparative study showed that the amount of total volatiles (flower, 95.0%, leaf, 92.9%, and stem, 95.0%) and the major constituent for the low molecular weight of essential oils were found to be better in HD of A. hamzaoglui. The oils were screened for antimicrobial activity against 12 microorganisms and showed antibacterial and antifungal activities against Escherichia coli, Staphylococcus aureus, Bacillus cereus 702 Roma, Mycobacterium smegmatis, and Saccharomyces cerevisiae. The antifungal activity was observed for the all tested oils against S. cerevisiae except stem oil of HD
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