7 resultados para Surface chemical composition

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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The essential oils isolated by hydrodistillation from trunk bark and leaves of Talauma ovata A. St. Hil. (Magnoliaceae), collected in four seasons, were analyzed by capillary GC and GC/MS. Altogether 52 components were identified, The oils were characterized by predominance of cyclic sesquiterpenes. The main components were linalool, trans-beta-guaiene, germaerene D, germacrene B, spathulenol, caryophyllene oxide, viridiflorol and alpha-endesmol. The content of individual components was variable during the year. All oils were screened against several strains of bacteria and yeasts, using the agar well-diffusion technique. The antimicrobial activity of oils showed strong dependence with the season. Significant activity was found for oils obtained in the spring and summer.

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The Pierre Auger Collaboration has reported. evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E > E(th) = 5.5 x 10(19) eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E > E(th) are heavy nuclei with charge Z, the proton component of the sources should lead to excesses in the same regions at energies E/Z. We here report the lack of anisotropies in these directions at energies above E(th)/Z (for illustrative values of Z = 6, 13, 26). If the anisotropies above E(th) are due to nuclei with charge Z, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.

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In this study, the isolation and characterization of chemical composition of C. langsdorffii (copaiba) fruit peel volatile oil from Alfenas - MG was carried out according to successive hydrodistillations, likewise the anti-inflammatory activity was evaluated by rat paw edema model. The chemical composition of the oil was determined by GC-MS analysis. The major components were (E)-caryophyllene, germacrene B, 1,5-epoxysalvial-4(14)-ene, caryophyllene oxide and isospathulenol. The inflammatory process was inhibited in 39 +/- 6 % (p<0.05, Tukey-Kramer) by one sample of essential oil. The C. langsdorffii fruit peel is a rich source of essential oil (3.8% w/w), and due to potential industrial interest of its components this ecotype presents feasible crop seeking productivity and it could constitutes in a good alternative to the sustainable use of this specie.

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Instrumental neutron activation analysis (INAA), have been used for the definition of compositional groups of potteries from Justino site, Brazil, according to the chemical similarities of ceramic paste. The outliers were identified by means of robust Mahalanobis distance. The temper effect in the ceramic paste was studied by means of modified Mahalanobis filter. The results were interpreted by means of cluster, principal components, and discriminant analyses. This work provides contributions for the reconstruction of the prehistory of baixo Sao Francisco region, and for the reconstitution of the Brazilian Northeast ceramist population of general frame.

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The chemical composition of the essential oil of Rollinia sericea (R.E.Fr.) R.E.Fr. leaves was determined by GC and GC/MS analysis. The analysis revealed the presence mainly of sesquiterpenes: beta-elemene (10%), beta-caryophyllene (10.0%), bicyclogermacrene (9.1%), germacrene-D (8.2%), bicycloelemene (6.2%) and (Z)-nerolidol (5.3%). Rollinia sericea oil was able to inhibit the growth of both fungi Aspergillus niger (16404) and Candida albicans (ATCC 10231) as well as the Gram-positive bacterium Staphyloccocus aureus (ATCC 6538) but it was inactive against the Gram-negative bacteria Escherichia coli (ATCC 8739) and Pseudomonas aeruginosa (ATCC 9027).

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The volatile Constituents of the fresh materials of Hypericum cordatum were isolated by hydrodistillation kind analyzed by CC and GC/MS. The leaves produced 0.04% of a yellowish essential oil and the flowers did not. The main components of the oil were myrcene (40.18%), alpha-pinene (16.40%), and limonene (12%). The antibacterial activities of the oil against Saccharomyces aureus and Escherichia coli and the anti-fungal activities of the oil against the fungi Cladosporium cladosporioides and C. sphaerospemum were evaluated. The oil showed an antibacterial activity against the bacteria S. aureus and anti-fungal activity against the two fungi.

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The chemical composition and the antimicrobial activity of the essential oil from Croton heterocalyx leaves were evaluated. The oil which was analyzed by GC and GUMS was found to contain germacrene D (12.5%), bicyclogermacrene (11.2%), delta-elemene (9.2%) beta-elemene (8.2%), spathulenol (6.9%), linalool (5.4%) and 1,8-cineole (3.7%) its major components. Croton. heterocalyx oil displayed a high inhibitory activity against the fungi Aspergillus niger (16404) and Candida albicans (ATCC 10231.) as well its the Gram-positive bacterium Staphylococcus aureus (ATCC 6538), hut a very weak activity was observed for the Gram-negative bacteria Escherichia coli (ATCC 8739) and Pseudomonas aeruginosa (ATCC 9027).