1,721,030 research outputs found
Calorimetric study of nitro group/solvent interactions. Comparison with DISQUAC predictions
No full textA flow microcalorimeter, model 2277-LKB, has been used to determine excess enthalpies, H(E), at 298.15 K, for liquid mixtures containing ethanenitrile, propanenitrile, butanentrile, or pentanenitrile + benzene or tetrachloromethane. These experimental results together with the literature data on thermodynamic properties of alkanenitrile + benzene or tetrachloromethane mixtures have been interpreted in terms of the dispersive quasi-chemical (DISQUAC) group contribution model. Two sets of structure-dependent interaction parameters, for the nitrile group/aromatic and for the nitrite group/tetrachloromethane contacts, have been obtained. The model provides a fairly consistent description of the excess Gibbs energy, G(E), excess enthalpy, H(E), and of activity coefficients at infinite dilution, gamma(infinity)(i), of the considered mixtures
Essential oil of Myrtus communis inhibits inflammation in rats by reducing serum IL-6 and TNF-α
No full textThe topical antiinflammatory activity of the essential oil of Myrtus communis L. was studied using croton oil induced ear edema and myeloperoxidase (MPO) activity in mice, and cotton pellet induced granuloma, and serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in rats. On topical application, the oil exhibited a significant decrease in the ear edema as well as MPO activity. The oil also inhibited cotton pellet-induced granuloma and serum TNF-α and IL-6. It can be concluded that the essential oil of Myrtus communis reduces leukocyte migration to the damaged tissue and exhibits antiinflammatory activity
Thermodynamic properties of binary mixtures containing oxaalkanes. Part VI. Monoethers, acetals, diethers, cyclic mono- and di-ethers +tetrachloromethane
No full textThe data available in the literature on thermodynamic properties concerning different oxaalkanes + tetrachloromethane mixtures are examined on the basis of the DISQUAC group contribution model. The obtained interaction parameters, dispersive and quasichemical, depend on the intramolecular environment of the O atom. The steric effect results in a regular decrease of the quasichemical interaction parameters of the oxygen/tetrachloromethane (e,d)-contact in linear ethers. The proximity effect of the O atoms generates lower coefficients in dioxaalkanes with respect to monooxaalkanes and because of the ring strain, being the quasichemical coefficients constant, the dispersive parameters in cyclic molecule are higher than in linear ethers
Bioactive extracts, obtained by supercritical CO2 extraction, from Citrus processing wastes
No full textCitrus plants belong to the Rutaceae family and include Citrus reticulata (sweet mandarin), Citrus paradisi (grapefruit), and Citrus limon (lemon); all of which are among the most popular fruits in the world. The main use of citrus fruits is to produce citrus juice, however, the processing waste of the citrus industry such as peel, pulp and seeds are also a potential source of valuable by-products. Citrus seeds are also used in the food, cosmetics and pharmaceutical industry. This study investigates the fixed oil obtained by supercritical CO2 extraction (SFE), at 250 bar and 40 °C, and by n-hexane in a Soxhlet apparatus (SE) from seeds of mandarin, lemon and grapefruit waste discarded by a local industry in Sardinia (Italy). High percentages of linoleic, from (35 to 42) %; oleic, (22 to 28) %; palmitic, (21 to 25) %; linolenic, (4 to 10) % and stearic, (4 to 7) % acids were observed in SFE Citrus seed oils. The fatty acid profiles of the three oils were similar; linoleic acid was the major fatty acid. The content of linolenic acid was higher in the lemon oil than in the mandarin and grapefruit seed SFE oils; 10 % with respect to 4 %. Citrus SFE oils were also evaluated for their attractant effect on the Mediterranean fruit fly Ceratitis capitata by behavioral assays. The three oils obtained by solvent extraction were identical to the ones obtained by means of SFE but without the additional benefit of not having unwanted traces of solvent
Influence of extraction methods on the composition of essential oils of Achillea millefolium L. from Lithuania
Full text linkIn this study, flowering aerial parts of Achillea millefolium were used as a matrix for supercritical CO2 extraction (SFE) of volatile oil. The collected extracts were analyzed by GC-FID and GC-MS methods and their composition were compared with that of the essential oil isolated by hydrodistillation (HD). The composition of the essential oil obtained by hydrodistillation and SFE methods is widely different. Indeed, the SFE volatile oil had a pale yellow color whereas the HD oil had a blue color due to the presence of chamazulene (48.0% vs. 4.3%). Other important constituents of HD oil were (E)- caryophyllene (19.5 %) and γ-muurolene (13.1%). The CO2 supercritical extract was dominated by (E)-caryophyllene (26.0%), γ-muurolene (22.0%), and caryophyllene oxide (8.1%)
Chemical composition of essential oils from needles of Pinus pinaster from Italy and from Tunisia
No full textThe chemical composition of the essential oil obtained from the needles of Pinus pinaster by hydrodistillation was analyzed by gas chromatography-mass spectrometry. Fifty components were detected, of which 41 were identified for a total percentage of about 98 %. The main components of the essential oil of needles from Tunisia were abietadiene (25.4 %), 13-epi-manoyl oxide (16.6 %), abietatriene (10.2 %), β-caryophyllene (11.1 %), 13(16), 14-labdien-8-ol (5.9 %) and α-pinene (5.3 %) whereas the oil from Italy was predominantly composed of limonene (36.7 %), abienol (13.4 %), manoyl oxide (6.5 %) and β-caryophyllene (5.8 %)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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