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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Caractérisation du bois de Mûrier blanc (Morus alba L.) en référence à son utilisation dans les luths Iraniens / Characterization of white Mulberry wood (Morus alba L.) considering its usage in Iranian lutes

Se Golpayegani Motamedi, Aida 18 November 2011 (has links)
L'objectif est de mieux connaître les diverses propriétés (physico-mécaniques, biologiques et chimiques) du bois de Mûrier blanc (Morus alba L.), en tant que matériau éminemment utilisé dans la fabrication de luths Iraniens. La différence de caractéristiques vibratoires de cette espèce a été mesurée en fonction de la présence d'extractibles, mais aussi pour trois traitements artisanaux qui ont été adaptés à l'échelle du laboratoire.Le bois Mûrier blanc est caractérisé par un module spécifique modéré, un amortissement plus bas que prévu et une anisotropie faible entre ses trois axes. Il est précisé que cette espèce ne peut pas être classifiée avec les mêmes normes que les autres bois utilisés pour les instruments classiques Européens. En utilisant les deux extractions indépendantes et successives, il est révélé que l'amortissement est régi par deux types d'extraits, certains l'abaissent et certains l'augmentent. Ces composés ne sont pas tous extractibles par les mêmes solvants. L'immersion de longue durée dans une eau à température ambiante ne modifie pas les propriétés mécaniques de l'espèce, toutefois, elle peut laisser le bois avec des défauts irréversibles. Un court traitement à l'eau chaude (70°C) entraîne l'augmentation de l'amortissement et la diminution du module spécifique. Dans ce dernier cas, des modifications sont presque progressives avec le temps.Le bois de Mûrier blanc semble être « très durable » par rapport à une attaque fongique, même dans des conditions extrêmes. Le délavage dans l'eau n'a pas d'effets sur la résistance de cette espèce contre basidiomycètes. Ce bois est classé « moyennement durable » contre l'attaque des termites et devient sensible après le délavage. Ses extractibles ont donc des effets toxique sur les termites. Les phénols, acides gras, stérols, hydrocarbures supérieurs, et composés aromatiques sont les composés présents dans les extraits de cette espèce. Le résorcinol, composé prédominant trouvé dans l'espèce, a été récemment rapporté comme la cause de plusieurs problèmes de santé, ce qui est aujourd'hui observé chez les artisans Iraniens. / This work aims at studying the several divers properties (Physico-mechanical, biological and chemical) of white Mulberry (Morus alba L.), as the leading material used in fabrication of Iranian lutes. The vibrational characteristic of this species is measured in relation with secondary metabolites (extractives) as well as three artisanal hygro-thermal treatments adapted to laboratory scale.White Mulberry wood is characterized with a moderate specific modulus, less than expected damping and a low anisotropy between three directions. It is specified that this species cannot be described with the same standards as other woods used in European classical instruments. Using independent and successive extractions reveal that two types of extraneous compounds govern the damping in this wood, some raising it, when the rest have a decreasing effect. These compounds are not all extractable by the same solvents.Long time immersion in water at ambient temperature hardly changes mechanical properties of the species, however, it can leave wood with irreversible defects. Hot water treatment at 70°C results for damping and moduli to be increased and decreased respectively. These changes are time related. Several mild desorption and adsorption cycles, seem to reduce damping without greatly endangering the moduli. White Mulberry wood is found to be very durable towards fungi, even in extreme conditions. Water leaching seems to be affectless on this species resistance towards basidiomycetes. This wood is rated moderately durable towards termites and becomes sensible after water leaching. Extractives seem to play important role in this wood natural resistance, as they are found to have toxic effect on termites. Resorcinol, a phenol, is the leading compound in the extractives of white Mulberry. Fatty acids, sterols, higher hydrocarbons, and aromatic compounds are also found as the constituents of secondary metabolites. Resorcinol is documented to cause irritations close to what is normally experienced by the fabricants working with white Mulberry for a long time.
22

Ekstrakti duda (Morus spp., Morasceae), sastav, delovanje i primena / Mulberry extracts (Morus spp., Morasceae), composition, activity and application

Radojković Marija 09 November 2012 (has links)
<p>&nbsp;Upotrebom različitih ekstragenasa izvr&scaron;ena je ekstrakcija ploda, lista i korena belog (<em>Morus alba</em> L.) i crnog duda (<em>Morus nigra</em> L. ). Ekstrakcija etanolom je izvr&scaron;ena pri predhodno određenim optimalnim uslovima ekstrakcije (70% koncentracija etanola, temperatura 60&deg;C i odnos rastvarač:droga 20 ml/g). Ispitan je hemijski sastav ekstrakata različitih delova duda. Ispitivanja hemijskog sastava etanolnih ekstrakata obuhvatala su određivanje sadržaja ukupnih fenola, ukupnih flavonoida, ukupnih i monomernih antocijana, kvalitativni i kvantitativni sastav polifenolnih komponenata, kao i sadržaj mikro-, makro- i toksičnih elemenata. Najvedi sadržaj ukupnih fenolnih jedinjenja određen je u ekstraktu korena <em>M. nigra</em> (186 mg EHK/g), a najvedi sadržaj flavonoidnih jedinjenja u ekstraktu lista <em>M. nigra</em> (67 mg ER/g). U ekstraktima lista duda po svom sadržaju u odnosu na ukupan sadržaj polifenolnih jedinjenja ističe se kafena kiselina (od 53,34 do 62,11%), dok se u ekstraktima korena izdvaja hlorogenska kiselina (udeo vedi od 74%). U pogledu mineralnog sastava ekstrakata relativno veliki sadržaj Ca i Mg je karakterističan za obe vrste ekstrakata (vedi od 1.400 &mu;g/g). Mikroelementi u svim ispitanim uzorcima duda po opadajudem nivou, su Fe, B, Zn, Cu i Mn. U ekstraktima dobijenim superkritičnim CO<sub>2 </sub>određen je sadržaj masnih kiselina i ukupnih karotenoida. U ispitivanim ekstraktima dominante su nezasidene masne kiseline, linolna i linolenska kiselina, a značajan je udeo i zasidene masne kiseline (palmitinske kiseline).</p><p>Ispitivanje delovanja ekstrakata obuhvatalo je evaluaciju antioksidativne aktivnosti pradenjem sposobnosti neutralizacije slobodnih radikala, redukcionog potencijala i inhibicije lipidne peroksidacije. Po svim primenjenim metodama najvedu aktivnost je pokazao ekstrakt lista crnog duda. U zavr&scaron;noj fazi rada ispitana je in vitro citotoksična aktivnost ekstrakata duda, njihovim delovanjem na rast tri delijske linije: Hep2, RD i L2OB. Ekstrakti lista <em>M. nigra</em> su se pokazali kao najpotentniji inhibitori&nbsp;rasta na sve tri delijske linije (IC<sub>50</sub>&lt;30 &mu;g/g). Na osnovu svih sprovedenih ispitivanja kao proizvod sa najboljim karakteristikama pokazao se ekstrakti lista <em>M. nigra</em>.</p> / <p>Using different extraction solvents extracts of fruit, leaves and roots of white (<em>Morus alba</em> L.) and black mulberry (<em>Morus nigra</em> L.) were prepared. Extraction by ethanol was carried out at the previously determined optimal extraction conditions (70% ethanol concentration, temperature 60&deg;C and the ratio of solvent: drug 20 ml/g). The chemical composition of extracts obtained from different parts of the mulberry were analysed. These analyses included the determination of total phenols, total flavonoids, monomeric and total anthocyanins, qualitative and quantitative composition of polyphenolic components, and the content of micro-, macro- and toxic elements. The highest phenolic content was determined in the extract of <em>M. nigra</em> root (186 mg ECA/ g), while the highest content of flavonoid compounds was determined in the extract of <em>M. nigra</em> leaves (67 mg ER/g). In the case of mulberry leaf extracts dominant phenolic compound, in relation to the total phenolic content, was caffeic acid (with contribution from 53.34 to 62.11%), while in the extracts of root extracts dominant phenolic compounds was chlorogenic acid (a higher proportion of 74%). In terms of mineral composition of the extracts relatively high content of Ca and Mg was characteristic of both types of extracts (greater than 1,400 mg/g). Measured content of trace elements in mulberry extracts decrease in the next order: Fe&gt; B&gt; Zn&gt; Cu&gt; Mn. In the extracts obtained by supercritical CO<sub>2</sub> fatty acids and total carotenoids were determined. In these extracts dominant unsaturated fatty acids were linoleic and linolenic acid. Also, significant proportion of saturated fatty acid (palmitic acid) has been detected.</p><p>Testing of extracts activity included the evaluation of antioxidant activity applying the methods based on: neutralize free radicals, reducing power potential and the inhibition of lipid peroxidation. All applied methods showed the highest activity of black mulberry leaf extract. In the final phase of work in vitro cytotoxic activity of mulberry extracts was examined. Their effect on growth of three cell lines: Hep2, RD, and L2OB were analysed. Extracts of <em>M. nigra</em> proved to be the most potent inhibitors of growth in all three cell lines (IC<sub>50</sub>&lt;30 mg/g). On the basis of all conducted tests it has been proven that <em>M. nigra</em> extracts are products with the best characteristics.</p>
23

The Diary from Qutang Gorge and the letters about Donner Lake : A literary study of Mulberry and Peach by Nie Hualing

Jiang Nyfelt, Ling January 2022 (has links)
Mulberry and Peach is a novel written in the 1970s by a Chinese American writer named Nie Hualing (1925- ). It contains overlapping letters and diaries with flashbacks and flashforwards in first-person narration. Taohong is the new identity after Sangqing’s schizophrenia in the USA in 1969-1970. The book starts with Taohong’s letter, which introduces the main female character Sangqing´s life stories, told through her diaries between 1945-the 1970s in four places of her diasporic lives from mainland China to Taiwan, then the USA. The aim of this thesis is to explore the title of the book, the prologue and the epilogue, Sangqing’s first Dairy on Qutang Gorge (1945), and the four letters from Taohong, using the close reading method and combining the theories and concepts of characterization and symbolism, impressionistic, female aesthetic, intertextuality in literature and the cultural symbols for a deep and detailed text reading analysis.

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