Dissertations / Theses on the topic 'Aromatico'
To see the other types of publications on this topic, follow the link: Aromatico.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Aromatico.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Oliveira, Alessandra Lopes de. "Extração supercritica de oleo aromatico de cafe torrado." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256375.
Full textAbstract:
Orientadores : Fernando Antonio Cabral, Marcos Nogueira EberlinTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-07-29T03:10:32Z (GMT). No. of bitstreams: 1 Oliveira_AlessandraLopesde_D.pdf: 61103342 bytes, checksum: 7e04e9a66bb59e984b7d5e3b8089ecf5 (MD5) Previous issue date: 2001
Resumo: O resumo podera ser visualizado no texto completo da tese digital
Abstract: The abstract is available with the full electronic digital document
Doutorado
Doutor em Engenharia de Alimentos
2
Carrero, Diego Alejandro Silva. "Prospesçao química e farmacológica das folhas de Nicandra physalodes Garent (L)." reponame:Repositório Institucional da UFC, 2016. http://www.repositorio.ufc.br/handle/riufc/22398.
Full textAbstract:
CARRERO, Diego Alejandro Silva. Prospesçao química e farmacológica das folhas de Nicandra physalodes Garent (L). 2016. 155 f. Dissertação (Mestrado em Química)-Universidade Federal do Ceará, Fortaleza, 2016.Submitted by Anderson Silva Pereira (anderson.pereiraaa@gmail.com) on 2017-03-21T19:08:07Z No. of bitstreams: 1 2016_dis_dascarrero.pdf: 4384524 bytes, checksum: b9a46b19cd27eb3f35ae430367211ef3 (MD5)
Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2017-03-23T18:20:48Z (GMT) No. of bitstreams: 1 2016_dis_dascarrero.pdf: 4384524 bytes, checksum: b9a46b19cd27eb3f35ae430367211ef3 (MD5)
Made available in DSpace on 2017-03-23T18:20:48Z (GMT). No. of bitstreams: 1 2016_dis_dascarrero.pdf: 4384524 bytes, checksum: b9a46b19cd27eb3f35ae430367211ef3 (MD5) Previous issue date: 2016
This work describes the isolation and characterization of nine compounds isolated from dichloromethane and ethyl acetate from leaves of Nicandra physalodes. The study was initiated with extract preparations, followed by successive classics chromatographic fractionations as: chromatography over silica gel, Sephadex LH- 20 gel and C18 cartridge solid phase extraction (SPE), as well as high-performance liquid chromatography (HPLC). The isolated compounds were analyzed by spectroscopic techniques 1H and 13C NMR, one and two-dimensional, and spectrometric techniques as IR and HR-ESI-MS. In total were isolated nine withanolides which are derivates from ergostane skeleton, being four belonging withanolides to group II, named as Np1, Np2, Np7 and Np9 (withanolides with the basic skeleton modified) and five belonging to group I, named as Np3, Np4, Np5, Np6 and Np8 (withanolides with the basic skeleton unmodified). According with a literature survey compounds nic-10 (Np1), nicandrenone (Np2), nic-7 (Np3), nic-2 (Np4) and nicaphysaline B (Np5) were previously reported to this species, but compounds 15 oxo-nicaphysaline B (Np6), 6-7dihidroxy-nicandrenone-10, (Np7), 24 -25dihidroxy-nicandrenone-2 (Np8), and 17-(1-metylpropan-2-one)- nicandrenone-10 (Np9) are being reported for the first time in the literature. Biological assays (antimicrobial, antifungal and larvicidal) were performed for the main compounds; however, the results were either negative or weakly active.
Neste trabalho é descrito o isolamento e caracterização de nove compostos isolados dos extratos diclorometano e acetato de etila, obtidos das folhas de Nicandra physalodes. O estudo foi iniciado com a preparação dos extratos, seguido de sucessivos fracionamentos cromatográficos clássicos como: cromatografia em coluna aberta utilizando sílica gel, gel de dextrana Sephadex LH-20, cartucho C-18 (SPE), além de cromatografia líquida de alta eficiência (CLAE). Os compostos isolados foram caracterizados através de técnicas espectroscópicas como RMN de 1H e 13C, uni e bidimensional, além de técnicas espectrométricas como IV e EMAR-ESI. No total foram isolados nove vitanolidos que são derivados do esqueleto ergostano, sendo quatro pertencentes ao grupo II, denominados Np1, Np2, Np7 e Np9 (vitanolidos com esqueleto base modificado) e cinco pertencentes ao grupo I, denominados Np3, Np4, Np5, Np6 e Np8 (vitanolidos com esqueleto base não modificado). De acordo com pesquisas realizadas na literatura e mediante comparação com dados de RMN de 1H e 13C, os compostos nic-10 (Np1), nicandrenona (Np2), nic-7 (Np3), nic-2 (Np4) e nicafisalina B (Np5), já haviam sido relatados na espécie, enquanto os compostos denominados como 15-oxo-nicafisalina B (Np6), 6-7dihidróxi-nicandrenona-10, (Np7), 24-25dihidróxi-nicandrenona-2, (Np8) e 17-(1-metilpropan-2-ona)-nicandrenona-10 (Np9), estão sendo relatados pela primeira vez. Foram realizados ensaios antimicrobiano, antifúngico e larvicida com os compostos isolados em maiores quantidades, porém os resultados forma negativos, ou fracamente ativos.
3
Fernandes, Sergio Antonio. "Aplicação da RMN de 1H para prever regiosseletividade do rearranjo de Claisen aromatico." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248652.
Full textAbstract:
Orientador : Anita Jocelyne MarsaioliDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-02T09:33:09Z (GMT). No. of bitstreams: 1 Fernandes_SergioAntonio_M.pdf: 3614422 bytes, checksum: a6ee0364a0bf0915e0a7bd0f9c905fd2 (MD5) Previous issue date: 2001
Mestrado
4
Trivellini, Nicola. "Nuovi copoliesteri aromatico-alifatici da fonte rinnovabile contenenti atomi di zolfo: relazione proprietà-struttura." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13433/.
Full textAbstract:
To date, in view of the continued growth of the production and use of plastic materials, the exploitation of non-renewable sources for their implementation and subsequent disposal of these huge piers, are extremely current issues and still far from being resolved. In parallel, the world of research, as well as that of industry, are moving more and more towards solutions that reduce the environmental impact as much as possible, both in terms of resource use, that of terrestrial and marine environmental protection. In this direction bioplastics, i.e. plastics from renewable sources or biodegradable (or both) and possibly recyclable, represent a highly sustainable answer to these problems. A monomer from renewable sources which allows the realization of polymers with excellent mechanical and barrier properties is the 2,5-furandicarbossilico acid, whose polyesters are not, however, biodegradable. Conversely, aromatic/aliphatic biodegradable copolymers are already present on the market, but they are not completely obtainable from renewable sources. In this context, the present research work focused on the study of new aromatic/aliphatic copolymers completely bio-based and biodegradable. The synthesized materials were also subjected to several analyzes, in order to study their properties in relation to possible industrial applications as substitutes for Ecoflex. In particular, they have been characterized from the structural, thermal, mechanical, point of view and finally it was evaluated their compostability. The results obtained have been correlated to chemical structure, i.e to copolymer composition.
5
Gamberini, Lorenzo. "Effetti del diametro sul profilo aromatico di salami fermentati impiegando due diverse colture starter." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14138/.
Full textAbstract:
Molti fattori contribuiscono alla formazione delle caratteristiche "tipiche" dei salami e tra questi l’impiego di colture starter e il diametro del budello svolgono un ruolo rilevante. Infatti il tipo di microrganismi presenti e la dimensione del prodotto influenzano importanti eventi che avvengono durante la maturazione (calo peso, attività proteoliche e lipolitiche) e che portano alla formazione di composti volatili. Recentemente, è stata studiata l’influenza del diametro sulle caratteristiche chimico-fisiche e aromatiche di salami a fine maturazione ma questi prodotti provenivano da materie prime differenti ed erano prodotti attraverso processi diversi. A seguito di questo lavoro preliminare, è stato effettuato un lavoro più ampio mirato alla valutazione dell'effetto del diametro e di due diverse colture starter sulla popolazione microbica e sulle caratteristiche chimico-fisiche in salami prodotti industrialmente. I prodotti sono stati periodicamente analizzati e nel corso del mio elaborato abbiamo studiato l’impatto delle variabili considerate (diametro e starter) sul profilo in molecole volatili e sulle caratteristiche organolettiche dei salami ottenuti. Dai risultati è emerso che l’aroma si differenziava principalmente in relazione al diametro e ciò può essere attribuito sia alle diverse tempistiche richieste per arrivare al prodotto finito, sia alla minore disponibilità di ossigeno nei campioni a diametro maggiore. L’influenza dello starter impiegato era invece inferiore. Questo potrebbe essere dovuto al fatto che per tutti i campioni sono state adottate condizioni industriali di fermentazione e maturazione non specifiche e quindi non adatte ad esaltare le peculiarità fisiologiche dei ceppi impiegati. Ciò sottolinea la necessità di ulteriori studi per ottimizzare le prestazioni degli starter in relazione al processo al fine di massimizzare le peculiarità dei prodotti, difendendone la differenziazione come un valore, oltre che economico, anche culturale.
6
Quental, Antonio Carlos. "Blendas de PHB e PETG : Formação de um copoliester aromatico/alifatico via processamento reativo." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248784.
Full textAbstract:
Orientador: Maria Isabel FelisbertiTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-04T02:10:54Z (GMT). No. of bitstreams: 1 Quental_AntonioCarlos_D.pdf: 15203986 bytes, checksum: d9b3385ec9f73b9e58c7bc6fa6e0ff9c (MD5) Previous issue date: 2004
Doutorado
Físico-Química
Doutor em Quimica
7
Mondati, Giulia. "Profilo aromatico e analitico di vino Sangiovese biodinamico di diverse annate in relazione all'andamento climatico." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/22065/.
Full textAbstract:
L’obbiettivo che questo studio si pone è quello di correlare gli effetti metereologici con il profilo aromatico e analitico del vino. Per la sua realizzazione sono stati utilizzati sei campioni di vino sangiovese di annate differenti, dal 2012 al 2017, provenienti dalla stessa azienda e con lo stesso uvaggio, a cui sono state applicate le medesime tecniche di vinificazione. In riferimento a questi campioni sono state raccolte le informazioni metereologiche che interessano l’intero anno, per tutti i sei anni consecutivi, e quindi dall’ingresso in dormienza della pianta fino al momento della raccolta. Nello specifico i parametri climatici valutati sono stati: temperatura, precipitazioni, bagnatura fogliare Umidità relativa, radiazione solare. Tali dati sono stati confrontati con i con i parametri enologici di base e con il profilo in molecole volatili di ciascun vino in ciascuna annata. U risultati hanno evidenziato la sussistenza di una relazione tra umidità relativa e tenore alcolico ottenuto dei vini; in particolare l’annata 2014, che ha mostrato i valori di umidità relativa dell’aria più elevata nei mesi di agosto e settembre, è stata caratterizzata da un vino con il minore tenore alcolico. Viceversa le annate più secche nei mesi della maturazione (2016 e 2017) hanno contribuito positivamente al grado alcolico del vino. Per quanto riguarda il profilo in molecole volatili, il confronto delle diverse annate ha evidenziato come, sotto il profilo qualitativo, i vini siano caratterizzati da composti di aromi differenti, presenti in diverse proporzioni e in funzione dell’annata. Nello specifico il campione caratterizzato dal maggiore accumulo di composti ad alto impatto olfattivo è il 2014.
8
Antoni, Inaldo de. "Influencia dos microorganismos Staphilococcus xylosus, Lactobacillus plantarum e Staphylococcus carnosus no perfil aromatico de salames de peru." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255239.
Full textAbstract:
Orientador: Nelson J. BeraquetTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-04T01:43:04Z (GMT). No. of bitstreams: 1 Antoni_Inaldode_D.pdf: 70750600 bytes, checksum: f9ed17bd6a14eb8c555c18b0a5f338a6 (MD5) Previous issue date: 2005
Doutorado
Tecnologia de Alimentos
Doutor em Tecnologia de Alimentos
9
DOMENEGHETTI, DANIELE. "Studio del profilo polifenolico ed aromatico di vini rossi da vitigni di antica coltivazione della Valle d'Aosta." Doctoral thesis, Università Cattolica del Sacro Cuore, 2007. http://hdl.handle.net/10280/73.
Full textAbstract:
La Valle d'Aosta, pur non avendo grandi superfici destinate alla viticoltura, è caratterizzata dalla presenza di un ricco patrimonio ampelografico di cui fanno parte dodici varietà autoctone a bacca rossa: Bonda, Cornalin, Crovassa, Fumin, Mayolet, Ner d'Ala, Petit rouge, Premetta, Roussin, Roussin de Morgex, Vien de Nus e Vuillermin.
Malgrado i numerosi vitigni menzionati, nella produzione dei vini a D.O.C troviamo in prevalenza il Petit rouge e poche altre varietà che, nell'insieme, rappresentano circa il 34% della produzione totale.
Al fine di implementare la presenza di prodotti tipici che esprimano i caratteri distintivi della zona di provenienza sono state approfondite le conoscenze dei vitigni autoctoni per evidenziarne le attitudini e le potenzialità per la produzione di vini rossi di qualità.
Allo stesso scopo sono stati valutati gli effetti dell'applicazione di alcune tecniche di vinificazione alternative sull'espressione dei caratteri qualitativi del Petit rouge, le cui uve sono da tempo vinificate in purezza o in assemblaggi nella produzione di vini a D.O.C.Aosta Valley has a little viticulture surface and it is characterised by a rich ampelographic collection including the following twelve red grape autochthonous varieties: Bonda, Cornalin, Crovassa, Fumin, Mayolet, Ner d'Ala, Petit rouge, Premetta, Roussin, Roussin de Morgex, Vien de Nus e Vuillermin. Only the 34% of the D.O.C. wine production is represented by some of the above mentioned cultivars, in particular the Petit Rouge, despite of the huge number of cultivars. The Petit rouge is used in purity or in miscellaneous in the D.O.C. wine production. In order to implement the presence of typical products, this study was carried out to evaluate the aptitude of Aosta Valley ancient grapes to produce quality red wines. Moreover to improve quality of the most diffused Aosta Valley red wine the effects of some alternative winemaking were evaluated on the Petit rouge characters.
10
DOMENEGHETTI, DANIELE. "Studio del profilo polifenolico ed aromatico di vini rossi da vitigni di antica coltivazione della Valle d'Aosta." Doctoral thesis, Università Cattolica del Sacro Cuore, 2007. http://hdl.handle.net/10280/73.
Full textAbstract:
La Valle d'Aosta, pur non avendo grandi superfici destinate alla viticoltura, è caratterizzata dalla presenza di un ricco patrimonio ampelografico di cui fanno parte dodici varietà autoctone a bacca rossa: Bonda, Cornalin, Crovassa, Fumin, Mayolet, Ner d'Ala, Petit rouge, Premetta, Roussin, Roussin de Morgex, Vien de Nus e Vuillermin.
Malgrado i numerosi vitigni menzionati, nella produzione dei vini a D.O.C troviamo in prevalenza il Petit rouge e poche altre varietà che, nell'insieme, rappresentano circa il 34% della produzione totale.
Al fine di implementare la presenza di prodotti tipici che esprimano i caratteri distintivi della zona di provenienza sono state approfondite le conoscenze dei vitigni autoctoni per evidenziarne le attitudini e le potenzialità per la produzione di vini rossi di qualità.
Allo stesso scopo sono stati valutati gli effetti dell'applicazione di alcune tecniche di vinificazione alternative sull'espressione dei caratteri qualitativi del Petit rouge, le cui uve sono da tempo vinificate in purezza o in assemblaggi nella produzione di vini a D.O.C.Aosta Valley has a little viticulture surface and it is characterised by a rich ampelographic collection including the following twelve red grape autochthonous varieties: Bonda, Cornalin, Crovassa, Fumin, Mayolet, Ner d'Ala, Petit rouge, Premetta, Roussin, Roussin de Morgex, Vien de Nus e Vuillermin. Only the 34% of the D.O.C. wine production is represented by some of the above mentioned cultivars, in particular the Petit Rouge, despite of the huge number of cultivars. The Petit rouge is used in purity or in miscellaneous in the D.O.C. wine production. In order to implement the presence of typical products, this study was carried out to evaluate the aptitude of Aosta Valley ancient grapes to produce quality red wines. Moreover to improve quality of the most diffused Aosta Valley red wine the effects of some alternative winemaking were evaluated on the Petit rouge characters.
11
Paladino, Andrea. "Utilizzo di pre-trattamenti per il miglioramento della sicurezza e del profilo aromatico di un prodotto spalmabile vegano." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16838/.
Full textAbstract:
Recentemente, nei laboratori del CIRI Agroalimentare è stato sviluppato, in collaborazione con un’azienda del settore, un nuovo prodotto fermentato a base di frutta secca, essiccato e maturato, per consumatori vegani. Sono state definite le condizioni di processo e le colture starter da impiegare nella fermentazione e il prodotto attualmente commercializzato può essere conservato a 4°C per 45 giorni. Le attività di ricerca sono proseguite su una versione fresca (crema spalmabile) ma questo non può essere visto come un prodotto ottenibile da uno step intermedio del processo già messo a punto poiché la mancanza dell’essiccamento pone importanti interrogativi sulla sicurezza igienico-sanitaria del prodotto, data la presenza di Enterobacteriaceae nella crema fresca, anche dopo il processo di fermentazione. Il processo deve essere quindi modificato ad hoc con lo scopo primario di eliminare questi microrganismi capaci di sopravvivere nelle condizioni applicate.
L’obiettivo di questo elaborato è stato quello di andare a valutare l’impatto di pre-trattamenti termici, effettuati sui semi in acqua a 90°C una o due volte, sulla sopravvivenza degli enterobatteri ed, in particolare, di E. coli e sul profilo aromatico del prodotto durante la produzione e la shelf life. I dati hanno dimostrato che la carica microbica viene abbattuta dopo il bagno a 90°C, indipendentemente dal trattamento, ma che permaneva una contaminazione nell’impianto di triturazione che ha suggerito modifiche sostanziali attraverso l’impiego di materiali più idonei alle necessità produttive e alla sanificazione.
Anche i profili aromatici dei due lotti non presentavano differenze rilevanti ma vi era una divisione netta tra i campioni in fase di fermentazione e i campioni raccolti durante la conservazione, dimostrando la necessità di una fase di affinamento per l’ottenimento degli aromi che vanno a connotare gradevolmente il prodotto.
12
Albonetti, Denise. "Studio del profilo aromatico della pesca. Stato dell'arte sulla caratterizzazione della composizione in volatili di pesche bianche e gialle." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/12790/.
Full textAbstract:
L’aroma, insieme a sapore e succosità, è uno dei componenti essenziali della qualità sensoriale della pesca, ed è da considerarsi una risposta integrata del sistema olfattivo a diversi composti volatili, quali alcoli, aldeidi, alcani, esteri, chetoni, lattoni e terpeni. La variabilità dei volatili nell’aroma della pesca dipende non soltanto da cultivar, gestione del frutteto, lavorazione, condizioni di conservazione, stadio di maturità e/o condizioni di maturazione, ma anche dalle procedure di estrazione e rilevamento attuate. In questo lavoro di tesi è stato condotto uno studio sullo stato dell’arte riguardante le tecniche analitiche maggiormente utilizzate per la determinazione dei volatili. In particolare, si è comparata la tecnica ritenuta più idonea all’estrazione di analiti volatili, ovvero la microestrazione in fase solida dello spazio di testa (HS-SPME), ad alcuni metodi tradizionali, tra i quali l’estrazione liquido-liquido (LLE), l’estrazione per distillazione in corrente di vapore (SDE) e la microestrazione liquido-liquido (LLME). Dai risultati riportati in bibliografia, la tecnica HS-SPME risulta essere quella con maggior percentuale di recupero di volatili, grazie alla rapidità di analisi e all’eliminazione dell’uso di solventi. Tuttavia, è emerso che alcune tecniche tradizionali sono più adatte per il campionamento di composti stabili, come svariati idrocarburi, non identificati con la tecnica HS-SPME. In conclusione, per ottenere risultati più completi ed attendibili, è consigliata la combinazione di più procedure di campionamento, in quanto complementari.
13
Quattrini, Nicolò. "Prosecco: storia e produzione del vino spumante più prodotto in Italia." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Find full textAbstract:
Negli ultimi anni si è sviluppata una tendenza favorevole ai vini spumanti e in particolar modo per il Prosecco, sia dal punto di vista economico che produttivo. Da qualche anno ormai il Prosecco ha superato lo Champagne per numero di bottiglie prodotte (462 milioni contro i 302 milioni dello Champagne), con un fatturato di 2,2 miliardi di euro (dati riferiti all’anno 2018). Il Prosecco nasce in un territorio nel quale cultura enologica, ambiente di coltivazione e vitigno hanno interagito in modo eccellente. In particolare, nelle colline trevigiane il Prosecco trova il suo terroir d’elezione, dove la conformazione e i terreni declivi della fascia collinare, i suoli e il clima, permettono di valorizzare le peculiarità del vitigno, il Glera, in grado di conferire al vino aromi varietali caratterizzati da note olfattive fruttate e floreali, sapientemente preservate nel corso delle operazioni di cantina. Questo elaborato mira ad illustrare le caratteristiche del territorio e delle tecniche enologiche utilizzate per questo prodotto, ambasciatore del Made in Italy enologico nel mondo.
14
Bonazzi, Erica. "Valutazione della shelf-life di un prodotto fermentato innovativo a base di frutta secca." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13679/.
Full textAbstract:
Questo elaborato costituisce l’ultima fase di messa a punto di un processo di un prodotto vegano innovativo (“formaggio” a base di frutta secca fermentata). Negli ultimi anni, con l’incremento del mercato dei prodotti vegani, molte aziende si sono rivolte a questa nicchia di consumatori implementando particolari processi produttivi per realizzare alimenti vegani stabili e sicuri da un punto di vista microbiologico. Nello specifico, grazie alla collaborazione tra un’industria del territorio e il CIRI Agroalimentare (UNIBO), partendo dallo studio di un prodotto artigianale e del consorzio microbico che guidava la sua fermentazione, si sono definite le condizioni per lo scale-up industriale, con un’attenzione particolare alle caratteristiche organolettiche e alla sicurezza igienico-sanitaria. In questo contesto, l’obiettivo dell’elaborato è stato quello di valutare la shelf-life del prodotto messo a punto definendo nel tempo l’evoluzione di numerosi parametri chimico fisici e microbiologici, sia durante una conservazione a 4°C, sia ad una temperatura di abuso termico (8°C). Essendo un prodotto innovativo, non è stato facile individuare i criteri per definire la shelf-life ma le sue caratteristiche intrinseche e le condizioni di confezionamento hanno fatto sì che il prodotto si dimostrasse sicuro e stabile (anche nel suo profilo aromatico) per tutto il corso della conservazione ad entrambe le temperature. Dal punto di vista igienico sanitario, i rischi possono essere legati soprattutto alla presenza di Listeria monocytogenes che però non può crescere ai valori di pH raggiunti attraverso il processo di fermentazione messo a punto. L’alta acidità del prodotto infatti garantisce l’inibizione degli eventuali patogeni presenti e limita lo sviluppo dei batteri degradativi. In virtù di questi risultati si può definire in 60 giorni la potenziale shelf-life del “formaggio” vegano, ovviamente se prodotto e mantenuto in condizioni idonee.
15
Bertazzoli, Giulia. "Caratterizzazione di ceppi di batteri lattici isolati da salami fermentati spontaneamente." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16786/.
Full textAbstract:
L’impiego di colture starter nell’industria delle carni fermentate è un fattore chiave per garantire la sicurezza dei prodotti, ma l’uso di pochi ceppi selezionati può comportare una perdita d’identità delle produzioni e un appiattimento delle loro peculiarità organolettiche. La ricerca di nuovi starter autoctoni è considerata fondamentale per proteggere questo aspetto, dunque un importante serbatoio di biodiversità è costituito da ceppi isolati da prodotti fermentati spontaneamente.
Lo scopo di questa tesi è stato quello di caratterizzare alcuni ceppi di batteri lattici isolati da 3 salami fermentati spontaneamente (senza l’uso di starter) di diversa provenienza (Brescia, Basilicata e Romagna). I ceppi isolati sono stati identificati prevalentemente (75%) come Lactobacillus sakei, mentre i restanti appartenevano a L. curvatus. Solo 2 isolati erano riconducibili a Leuconostoc mesenteroides, batteri lattici eterofermentati. Gli isolati sono stati testati per la loro capacità di produrre amine biogene e per il loro profilo aromatico. Tutti i L. sakei hanno confermato la loro incapacità a produrre amine biogene e solo un L. curvatus produceva putrescina, ottenuta dalla decarbossilazione dell’ornitina, prodotto finale della via dell’arginina deiminasi, importante una volta consumati tutti gli zuccheri disponibili in substrati carnei. Con l’analisi della produzione d’aromi, come messo in evidenza dalla PCA, è stato osservato come la fonte di isolamento ha dato luogo ad isolati con caratteristiche diverse, permettendo una loro netta separazione sulla base della provenienza ed evidenziando un’elevata diversità fenotipica di queste specie.
Questo screening è indirizzato dunque alla ricerca di nuovi potenziali starter per l’industria dei salami, per meglio combattere la standardizzazione del prodotto determinata dall’uso di relativamente poche colture starter, favorendo la difesa della tipicità e della riconoscibilità di piccole produzioni tradizionali.
16
Sgarzi, Luca. "Effetti degli starter e delle condizioni di maturazione su salami tipici." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3693/.
Full textAbstract:
In questo lavoro, sono stati analizzati come caso di studio due tipi di salami fermentati italiani (tipo Felino e tipo Milano). Lo scopo è stato quello di valutare l’effetto di diverse condizioni ambientali nelle celle d’asciugamento e l’effetto di diverse colture starter sulle caratteristiche dei salami di produzione industriale. Alla fine della maturazione, i salami ottenuti sono stati analizzati per determinare i conteggi microbici, l’accumulo di ammine biogene (AB) e il profilo aromatico volatile, mediante l’utilizzo delle analisi SPME-GC. Questi profili sono stati confrontati con i risultati di un gruppo panel esperto. I salami tipo Felino, inoculati solo con Stafilococchi, sono stati caratterizzati da un lento abbassamento del pH e dalla presenza di alti contenuti di AB. Inoltre, sono state osservate le attività enzimatiche specifiche degli Stafilococchi, come il metabolismo della fenilalanina, che hanno modificato radicalmente i profili volatili del prodotto. Anche le diverse condizioni d’asciugamento applicate sono state in grado d’influenzare alcune caratteristiche sensoriali dei prodotti finali come la durezza e la masticabilità che mostrano diverse cinetiche di perdita d’acqua.
17
Lovat, Giacomo. "Self-assembly and on-surface chemistry of organic semiconductors on TiO2." Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/10894.
Full textAbstract:
2013/2014Understanding and controlling the ordering and functionality of organic semiconductors coupled to a dielectric surface, besides constituting a fascinating topic in basic science, has the potential to foster the development of many novel technologies, ranging from efficient and inexpensive photovoltaic cells to flexible electronic components. In the present doctoral work, the well-characterized (110) surface of Rutile TiO2 single crystals, r-TiO2(110), has been selected as an archetypal dielectric substrate for the templated growth of organic molecules and the assessment of their physico-chemical properties at the interface. In particular, this thesis provides: i. a detailed picture of the bonding and structural properties of two polycyclic aromatic hydrocarbons, and ii. a comprehensive study of the electronic structure and on-surface chemistry of three heteroaromatic molecules; both i. and ii. with regard to the interface with r-TiO2(110) in an ultra-high vacuum (UHV) environment. The determination of the electronic and structural properties at the organodielectric interfaces has been achieved via a multitechnique experimental approach consisting of the combination between scanning tunneling microscopy (STM) and electron spectroscopies with synchrotron radiation. While the former can reveal the geometrical details of single adsorbed species, and allow for a close, direct-space inspection of their molecular packing and ordering, the latter provides information on the electronic states and chemical composition of the overlayer. STM has been applied to systems in i. so as to complement the existing knowledge of their electronic structure with structural details on a scale length ranging from several hundred molecules down to a single molecule. Subsequently, a full microscopic and spectroscopic characterization of the interfaces in ii., on which scarce studies are currently available, has been conducted, with particular emphasis on the chemical reactions triggered by thermal annealing. To get a deeper insight into the experimental findings and facilitate their interpretation, selected systems have been modeled by two groups of theoreticians with numerical simulations based on density functional theory (DFT) formalism. The interfaces studied in part i. comprise tetracarboxylic-acid-diimide (PTCDI), a heteroaromatic acceptor, and perylene, an all-carbon aromatic donor, in contact with the r-TiO2(110)-1x1 surface. The substrate twofold symmetry and the large surface corrugation provided by the protruding oxygen rows favor the alignment of the PTCDI long axis along the [001] direction, parallel to the surface rows. STM images reveal that the growth of PTCDI proceeds via island nucleation; there is no evidence for any preferential roles in adsorption played by defect sites, be them oxygen vacancies or hydroxyl groups. Each island consists of aligned monomers adsorbed atop the oxygen rows, and coupled head-to-tail via one hydrogen bond per two facing imide terminations. The competition between molecule-substrate interaction, which displays a mixed van der Waals/covalent character, and intermolecular hydrogen bonds originates a fivefold periodicity in the island with respect to the underlying surface unit cell along the [001] direction, as pointed out by previous He atom scattering studies. In the [1-10] direction, orthogonal to the surface rows, adjacent monomers organize in stripes with one monomer per oxygen row. Such a dense packing is attributed to a strong side-by-side attraction between the electron-deficient rim of one monomer and the $\pi$ electron system of the one at its side, made possible by a moderate tilt angle of PTCDI about its long axis (35°). A similar adsorption geometry emerges for perylene, albeit with some remarkable differences of the self-assembly mechanism. At low coverage, monomers sparsely populate the surface titanium troughs, showing a rather weak intermolecular attraction. As the coverage increases up to a full monolayer, perylene molecules gradually fill the available space in the titanium troughs until a wetting layer is formed and no sticking of additional material is observed due to very weak pi-type interactions between stacked dimers. The side-by-side coupling between tilted monomers in the monolayer favors the coalescence of ordered domains extended across the substrate rows, although frequent line defects disrupt the long range order. Part ii. focuses on the interface between r-TiO2(110) and two classes of heterocyclic compounds: phthalocyanines and porphyrins. The interfacial electronic structure, morphology, conformation and chemical reactivity of in situ grown thin films of metal-free phthalocyanine (2H-Pc), tetraphenyl-porphyrin (2H-TPP) and tert-butyl tetraphenyl-porphyrin (2H-tbTPP) have been extensively investigated by means of STM and electron spectroscopies. The surface sensitivity and chemical selectivity of soft X-ray photoemission (XPS, photon energies 100-1000 eV) and near-edge X-ray absorption (NEXAFS) allowed to monitor the chemical state of the species upon adsorption as well as the orientation of their molecular plane relative to the crystal surface. The differences in the electronic structure and chemical reactivity among the adsorbed heterocycles have been analyzed and correlated to the type of peripheral environment surrounding the macrocycle, i.e. their chemically active part. The experimental results point to the existence of a reaction unaffected by the type of side substituents: the conversion of the macrocyclic aza-type nitrogen atoms to pyrrolic-type nitrogens. Conversely, self-metalation, i.e. the incorporation into the macrocycle of a Ti ion extracted from the substrate, is demonstrated with STM and X-ray spectroscopy for the three compounds, but with significant temperature variations among them. While self-metalation in 2H-Pc starts at room temperature and is quickly completed at 90°C, in 2H-TPP a similar metalation rate of molecules is achieved at 150°C, and in 2H-tbTPP, where two bulky tert-butyl groups departing from each peripheral phenyl ring act as inert spacers increasing the macrocycle distance from the surface, the energy barrier for the activation of the reaction is increased further and self-metalation is quickly achieved only at 200°C. Therefore, one concludes that a careful selection of side substituents proves to be a successful approach towards the tuning of chemical reactivity of these macrocyclic compounds on a metal oxide surface.
XXVII Ciclo
1987
18
Ferrizzi, Vitor Cid [UNESP]. "Caracterização de hidrocarbonetos policíclicos aromáticos (HPA) em rios da bacia hidrográfica do Turvo/Grande." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/97764.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:29:06Z (GMT). No. of bitstreams: 0
Previous issue date: 2011-08-26Bitstream added on 2014-06-13T20:38:18Z : No. of bitstreams: 1
ferrizzi_vc_me_sjrp.pdf: 1611524 bytes, checksum: dc7ddb08f93a8a08f46ca06614d12b8d (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Hidrocarbonetos Policíclicos Aromáticos (HPA) fazem parte de uma classe de compostos denominados Substâncias Tóxicas Persistentes, tendo como principais características elevada toxicidade e persistência no ambiente, sendo as fontes petrogênicas, pirogênicos e biogênicas as que mais contribuem para o aporte destes compostos. A Bacia Hidrográfica do Turvo/Grande (BHTG) é caracterizada por pequenos parques industriais e intensa atividade agrícola com destaque a cana-de-açúcar, que vem acompanhada por processos de queimadas. Neste contexto, este trabalho teve como principal objetivo utilizar a determinação de 1-hidróxipireno em bílis de peixes como biomarcador de exposição para HPA e também determinar o histórico destes em sedimentos de rios da BHTG. As coletas de amostras de peixe (160 amostras) e sedimento (superficial e profundidade) nos rios Preto (CAPRP), Turvo (PORTUR e RTURG) e Grande (RGRANDE) foram feitas em dois períodos distintos: fevereiro e julho de 2010. A determinação do 1-hidroxipireno nas amostras de bílis de peixes foi realizada de acordo com o método proposto por Ariase et alii (1993). Os HPA dos sedimentos foram extraídos de acordo com o método 3540C (EPA) e a quantificação foi realizada empregando Cromatografia Líquida de Alta Eficiência com detector de Fluorescência (HPLC-DF). As concentrações do 1-hidróxipireno no ponto RTURG da coleta de fevereiro de 2010 variaram na faixa de 210 a 1025 µg L-1, com valor médio de 780 ± 281 µg L-1. Para as amostras de peixes coletadas em julho de 2010 no ponto CAPRP, os valores estiveram na faixa de 397 - 6463 µg L-1, com valor médio de 1300 ± 1130 µg L-1. Para os pontos PORTUR e RTURG, os valores médios de concentração de 1-hidróxipireno na bílis dos peixes foram...
Polycyclic Aromatic Hydrocarbons (PAHs) constitute a class of compounds denominated as Persistent Toxic Substances, having as main characteristics high toxicity and persistence in the environment, being that the sources petrogenic, pyrogenic and biogenic contribute most to the intake of these compounds. Turvo/Grande watershed (BHTG) is characterized by a small industrial facilities and intensive agriculture especially sugarcane activity, which is accompanied by the burning process. In this context, this work aimed to use the determination of 1-hydroxypyrene in fish bile as a biomarker of exposure to PAHs and also determine the history of these in the sediments from BHTG rivers. The sampling of fish (160 samples) and sediment (surface and deep) in the Preto (CAPRP), Turvo (PORTUR e RTURG) e Grande (RGRANDE) rivers, were made in two distinct periods: February and July of 2010. The determination of 1-hydroxypyrene in fish bile samples was performed according to the method proposed by Ariase et alii (1993). PAHs were extracted of the sediments according to the method 3540C (EPA) and the quantification was performed using high performance liquid chromatography with fluorescence detector (HPLC-FD). Concentrations of 1-hydroxypyrene is fish bile samples collected in RTURG (February 2010) ranged from 210 to 1025 µg L-1, the average values 780 ± 281 µg L-1. For fish samples collected in CAPRP in July 2010 , values ranged 397-6463 µg L-1, with an average of 1300 ± 1130 µg L-1. For PORTUR and RTURG, the mean concentration of 1-hydroxypyrene in fish bile were 1643 ± 744 µg L-1 and 588 ± 183 µ g L-1, respectively. PAHs concentration along the sediment profile showed similar behavior. In general, for all PAHs there was a trend of reduction with increasing depth in sediment cores. The total concentration... (Complete abstract click eletronic access below)
19
Ferrizzi, Vitor Cid. "Caracterização de hidrocarbonetos policíclicos aromáticos (HPA) em rios da bacia hidrográfica do Turvo/Grande /." São José do Rio Preto : [s.n.], 2011. http://hdl.handle.net/11449/97764.
Full textAbstract:
Orientador: Altair Benedito MoreiraBanca: Eduardo Alves de Almeida
Banca: Ronaldo José Torres
Resumo: Hidrocarbonetos Policíclicos Aromáticos (HPA) fazem parte de uma classe de compostos denominados Substâncias Tóxicas Persistentes, tendo como principais características elevada toxicidade e persistência no ambiente, sendo as fontes petrogênicas, pirogênicos e biogênicas as que mais contribuem para o aporte destes compostos. A Bacia Hidrográfica do Turvo/Grande (BHTG) é caracterizada por pequenos parques industriais e intensa atividade agrícola com destaque a cana-de-açúcar, que vem acompanhada por processos de queimadas. Neste contexto, este trabalho teve como principal objetivo utilizar a determinação de 1-hidróxipireno em bílis de peixes como biomarcador de exposição para HPA e também determinar o histórico destes em sedimentos de rios da BHTG. As coletas de amostras de peixe (160 amostras) e sedimento (superficial e profundidade) nos rios Preto (CAPRP), Turvo (PORTUR e RTURG) e Grande (RGRANDE) foram feitas em dois períodos distintos: fevereiro e julho de 2010. A determinação do 1-hidroxipireno nas amostras de bílis de peixes foi realizada de acordo com o método proposto por Ariase et alii (1993). Os HPA dos sedimentos foram extraídos de acordo com o método 3540C (EPA) e a quantificação foi realizada empregando Cromatografia Líquida de Alta Eficiência com detector de Fluorescência (HPLC-DF). As concentrações do 1-hidróxipireno no ponto RTURG da coleta de fevereiro de 2010 variaram na faixa de 210 a 1025 µg L-1, com valor médio de 780 ± 281 µg L-1. Para as amostras de peixes coletadas em julho de 2010 no ponto CAPRP, os valores estiveram na faixa de 397 - 6463 µg L-1, com valor médio de 1300 ± 1130 µg L-1. Para os pontos PORTUR e RTURG, os valores médios de concentração de 1-hidróxipireno na bílis dos peixes foram... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Polycyclic Aromatic Hydrocarbons (PAHs) constitute a class of compounds denominated as Persistent Toxic Substances, having as main characteristics high toxicity and persistence in the environment, being that the sources petrogenic, pyrogenic and biogenic contribute most to the intake of these compounds. Turvo/Grande watershed (BHTG) is characterized by a small industrial facilities and intensive agriculture especially sugarcane activity, which is accompanied by the burning process. In this context, this work aimed to use the determination of 1-hydroxypyrene in fish bile as a biomarker of exposure to PAHs and also determine the history of these in the sediments from BHTG rivers. The sampling of fish (160 samples) and sediment (surface and deep) in the Preto (CAPRP), Turvo (PORTUR e RTURG) e Grande (RGRANDE) rivers, were made in two distinct periods: February and July of 2010. The determination of 1-hydroxypyrene in fish bile samples was performed according to the method proposed by Ariase et alii (1993). PAHs were extracted of the sediments according to the method 3540C (EPA) and the quantification was performed using high performance liquid chromatography with fluorescence detector (HPLC-FD). Concentrations of 1-hydroxypyrene is fish bile samples collected in RTURG (February 2010) ranged from 210 to 1025 µg L-1, the average values 780 ± 281 µg L-1. For fish samples collected in CAPRP in July 2010 , values ranged 397-6463 µg L-1, with an average of 1300 ± 1130 µg L-1. For PORTUR and RTURG, the mean concentration of 1-hydroxypyrene in fish bile were 1643 ± 744 µg L-1 and 588 ± 183 µ g L-1, respectively. PAHs concentration along the sediment profile showed similar behavior. In general, for all PAHs there was a trend of reduction with increasing depth in sediment cores. The total concentration... (Complete abstract click eletronic access below)
Mestre
20
Bianchi, Enrico. "Nuovo copolimero multiblocco a base di acido polilattico e acido 2,5-furandicarbossilico 100% biobased e compostabile per packaging sostenibile." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20697/.
Full textAbstract:
Questo progetto di tesi sperimentale è incentrato sulla sintesi di un copolimero multiblocco alifatico/aromatico a partire da reagenti aventi origine da fonti rinnovabili. L’applicazione proposta per il prodotto è nell’ambito del packaging sostenibile. E’ stato prima sintetizzato il poli(pentametilene furanoato) idrossil-terminato (PPeF-OH) a partire dall’acido 2,5-furandicarbossilico; esso è stato poi sottoposto ad una reazione di estensione di catena con acido poli-L-lattico (PLLA) parzialmente depolimerizzato. L’innovativa strategia di sintesi utilizzata è in linea con i principi della green chemistry, partendo da building block bio-based ed evitando l’uso di solventi. Il copolimero finale, definito P(LLA50PeF50)-CE, è stato caratterizzato dal punto di vista molecolare, strutturale e termico attraverso, rispettivamente, analisi NMR e GPC, WAXS, TGA e DSC. Sono state anche effettuate prove a trazione, test delle proprietà barriera e valutazione della compostabilità. I risultati dimostrano che la stabilità termica del PLLA è stata migliorata, determinando anche un allargamento della finestra di processabilità del materiale; la rigidità e la fragilità del PLLA sono state ridotte, rendendo il nuovo materiale idoneo alla realizzazione di film per imballaggi flessibili. La permeabilità all’ossigeno del PLLA è stata migliorata del 40% circa e un analogo miglioramento è stato riscontrato anche rispetto all’anidride carbonica. Infine, la compostabilità del PLLA non è stata compromessa.
21
Sugauara, Lucy Elaine [UNESP]. "Influência da fuligem da queima de palha de cana-de-açucar na presença de HPA em hortaliças de consumo humano." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/110842.
Full textAbstract:
Made available in DSpace on 2014-12-02T11:16:38Z (GMT). No. of bitstreams: 0
Previous issue date: 2014-01-17Bitstream added on 2014-12-02T11:21:05Z : No. of bitstreams: 1
000748808_20160131.pdf: 1145880 bytes, checksum: 9fb3124f890c373c2a716642bfa96e7a (MD5) Bitstreams deleted on 2016-02-01T10:15:55Z: 000748808_20160131.pdf,. Added 1 bitstream(s) on 2016-02-01T10:16:45Z : No. of bitstreams: 1
000748808.pdf: 4286658 bytes, checksum: 8f952ac5669d4bfdeb244e9023369477 (MD5)Os HPA são contaminantes orgânicos formados tanto na queima da palha de cana-de-açúcar quanto de combustível fóssil e por suas características físicoquímicas estão associados ao material particulado fino, podendo assim ser transportado a longas distâncias em um curto espaço de tempo dependendo das condições climáticas. Pelas características de mutagenicidade, carcinogecidade e alteração endócrina são substâncias que tem merecido interesse dos pesquisadores na avaliação da exposição humana por diversas vias, sendo a via alimentar a menos explorada atualmente. Este trabalho teve por objetivo otimizar e validar um método para determinação de HPA em hortaliças e avaliar a presença destas substancias em alface, couve e rúcula , em localidades com e sem a influência da queima de cana-de-açúcar (Araraquara e Itu). O método otimizado e validado neste trabalho envolve extração por banho de ultrassom e detecção por HPLC/FLU, possui valores aceitáveis de LD e LQ de acordo com a União Européia, 0,3 e 0,9 µg kg-1 respectivamente e valores de CV (<11,6%) e recuperação (70~119%), de acordo com os valores preconizados pela ANVISA. Amostras de alface, rúcula e couve cultivados em duas cidades em três diferentes locais, Araraquara (zona rural e zona urbana) e Itu (zona urbana) no período correspondente a safra (agosto de 2012) e entressafra (março 2013) da cana-de-açúcar foram analisadas. As concentrações de HPA encontradas nestas hortaliças situaram-se abaixo dos níveis reportados na literatura em folhas de diferentes espécies vegetais. No entanto, quando considerada a ingestão de 200g/dia, metade do preconizado pela OMS (Organização Mundial de Saúde) para ingestão diária recomendada de legumes, frutas e verduras, infere-se que a quantidade de HPA ingerida por esta via corresponderia a uma dieta de alta exposição MOE (Margin of Exposure) <10 000 próximos aos limites considerados preocupantes pela União Européia.
The PAH are a class of organic contaminants which are formed in burning of sugarcane and fossil fuel. The physicochemical properties are associated with their affinity for fine particulate matter and can therefore be transported over long distances in a short time depending on the weather. The PAH have characteristics of mutagenicity, carcinogenicity and endocrine disruption, because of these characteristics they are substances that have earned interest of researchers in the evaluation of human exposure via differents routes of uptake, and currently the dietary is the less explored. This study aimed to optimize and validate a method for the determination of PAH in vegetables and evaluate the presence of these substances in lettuce , kale and arugula, in locations with and without the influence of sugarcane burning (Araraquara and Itu). The optimized and validated method in this work involves extraction by ultrasound bath and detection by HPLC/FLU, also has acceptable values of LOD and LOQ in accordance with the European Union , 0.3 and 0.9 μg kg- 1 respectively , and the CV (<11.6%) and recovery values (70 ~ 119 %), are also in accordance to the values recommended by ANVISA . Samples of lettuce , arugula and kale grown in two different cities on three sites , Araraquara (rural and urban areas) and Itu (urban area) corresponding to the harvest period (August 2012) and sugarcane off season (March 2013) were analyzed. Concentrations of PAH found in these vegetables were below the levels reported in the literature in leaves of different plant species . However, when considering the intake of 200g/day, half the daily intake of fruits and vegetables recommended by WHO (World Health Organization ) it is inferred that the amount of PAH ingested in this way corresponds to a High exposure diet with MOE ( Margin of exposure) < 10 000 near the limits considered worrisome by the European Union.
22
Sugauara, Lucy Elaine. "Influência da fuligem da queima de palha de cana-de-açucar na presença de HPA em hortaliças de consumo humano /." Araraquara, 2014. http://hdl.handle.net/11449/110842.
Full textAbstract:
Orientador: Mary Rosa Rodrigues de MarchiBanca: Mario Sergio Galhiane
Banca: Flávio Sares Silva
Resumo:Os HPA são contaminantes orgânicos formados tanto na queima da palha de cana-de-açúcar quanto de combustível fóssil e por suas características físico-químicas estão associados ao material particulado fino, podendo assim ser transportado a longas distâncias em um curto espaço de tempo dependendo das condições climáticas. Pelas características de mutagenicidade, carcinogecidade e alteração endócrina são substâncias que tem merecido interesse dos pesquisadores na avaliação da exposição humana por diversas vias, sendo a via alimentar a menos explorada atualmente. Este trabalho teve por objetivo otimizar e validar um método para determinação de HPA em hortaliças e avaliar a presença destas substancias em alface, couve e rúcula , em localidades com e sem a influência da queima de cana-de-açúcar (Araraquara e Itu). O método otimizado e validado neste trabalho envolve extração por banho de ultrassom e detecção por HPLC/FLU, possui valores aceitáveis de LD e LQ de acordo com a União Européia, 0,3 e 0,9 μg kg-1 respectivamente e valores de CV (<11,6%) e recuperação (70~119%), de acordo com os valores preconizados pela ANVISA. Amostras de alface, rúcula e couve cultivados em duas cidades em três diferentes locais, Araraquara (zona rural e zona urbana) e Itu (zona urbana) no período correspondente a safra (agosto de 2012) e entressafra (março 2013) da cana-de-açúcar foram analisadas. As concentrações de HPA encontradas nestas hortaliças situaram-se abaixo dos níveis reportados na literatura em folhas de diferentes espécies vegetais. No entanto, quando considerada a ingestão de 200g/dia, metade do preconizado pela OMS (Organização Mundial de Saúde) para ingestão diária recomendada de legumes, frutas e verduras, infere-se que a quantidade de HPA ingerida por esta via corresponderia a uma dieta de alta exposição MOE (Margin of Exposure) <10 000...
Abstract: The PAH are a class of organic contaminants which are formed in burning of sugarcane and fossil fuel. The physicochemical properties are associated with their affinity for fine particulate matter and can therefore be transported over long distances in a short time depending on the weather. The PAH have characteristics of mutagenicity, carcinogenicity and endocrine disruption, because of these characteristics they are substances that have earned interest of researchers in the evaluation of human exposure via differents routes of uptake, and currently the dietary is the less explored. This study aimed to optimize and validate a method for the determination of PAH in vegetables and evaluate the presence of these substances in lettuce , kale and arugula, in locations with and without the influence of sugarcane burning (Araraquara and Itu). The optimized and validated method in this work involves extraction by ultrasound bath and detection by HPLC/FLU, also has acceptable values of LOD and LOQ in accordance with the European Union , 0.3 and 0.9 μg kg- 1 respectively , and the CV (<11.6%) and recovery values (70 ~ 119 %), are also in accordance to the values recommended by ANVISA . Samples of lettuce , arugula and kale grown in two different cities on three sites , Araraquara (rural and urban areas) and Itu (urban area) corresponding to the harvest period (August 2012) and sugarcane off season (March 2013) were analyzed. Concentrations of PAH found in these vegetables were below the levels reported in the literature in leaves of different plant species . However, when considering the intake of 200g/day, half the daily intake of fruits and vegetables recommended by WHO (World Health Organization ) it is inferred that the amount of PAH ingested in this way corresponds to a High exposure diet with MOE ( Margin of exposure) < 10 000 near the limits considered worrisome by the European Union.
Mestre
23
Arvapally, Ravi K. "Sensitization of Lanthanides and Organic-Based Phosphorescence via Energy Transfer and Heavy-Atom Effects." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc28388/.
Full textAbstract:
The major topics discussed are the phosphorescence sensitization in the lanthanides via energy transfer and in the organics by heavy atom effects. The f-f transitions in lanthanides are parity forbidden and have weak molar extinction coefficients. Upon complexation with the ligand, ttrpy (4'-p-Tolyl-[2,2':6',2"]-terpyridine) the absorption takes place through the ligand and the excitation is transferred to the lanthanides, which in turn emit. This process is known as "sensitized luminescence." Bright red emission from europium and bright green emission from terbium complexes were observed. There is ongoing work on the making of OLEDs with neutral complexes of lanthanide hexafluoroacetyl acetonate/ttrpy, studied in this dissertation. Attempts to observe analogous energy transfer from the inorganic donor complexes of Au(I) thiocyanates were unsuccessful due to poor overlap of the emissions of these systems with the absorptions of Eu(III) and Tb(III). Photophysics of silver-aromatic complexes deals with the enhancement of phosphorescence in the aromatics. The heavy atom effect of the silver is responsible for this enhancement in phosphorescence. Aromatics such as naphthalene, perylene, anthracene and pyrene were involved in this study. Stern Volmer plots were studied by performing the quenching studies. The quenchers employed were both heavy metals such as silver and thallium and lighter metal like potassium. Dynamic quenching as the predominant phenomenon was noticed.
24
Tazzari, Andrea. "Influenza della consociazione con salvia sugli aromi primari del Trebbiano Romagnolo." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Find full textAbstract:
La maggiore consapevolezza dei cittadini sui danni causati dall’inquinamento ambientale e la coscienza dell’importanza della salubrità dei prodotti alimentari stimolano le ricerche sull’AgroEcologia. Questa tendenza è particolarmente marcata nel settore vitivinicolo, soprattutto in conseguenza del ruolo culturale e sociale svolto dalla vite e dal vino. Il Lavoro di Tesi è stato realizzato nell’anno 2019-2020 in un vigneto della cv Trebbiano Romagnolo, impiantato nel 2003, sito presso l’Azienda Agricola Biologica e Faro AgroEcologico Podere Casetta di Sant’Agata sul Santerno (RA), che durante la collaborazione è approdato alla costituzione di una Comunità a Supporto dell’Agricoltura (CSA). La ricerca ha consentito di caratterizzare il profilo aromatico del Trebbiano Romagnolo, vitigno molto importante per la sua diffusione, ma scarsamente conosciuto per i composti aromatici, e di valutare gli effetti della consociazione con salvia sulla composizione aromatica delle bacche. Sono stati identificati e quantificati 98 composti aromatici. Le classi delle aldeidi e degli alcoli sono risultate prevalenti da un punto di vista quantitativo. È stata altresì dimostrata la capacità della salvia di modificare la composizione aromatica dell’uva, riconducibile alla possibile influenza sulle lipossigenasi, le quali intervengono sulla sintesi di composti C-6, da parte dei composti organici volatili (VOCs) emessi dalla salvia. Tra i VOCs emessi nell’atmosfera dalle piante di salvia, ne sono stati riscontrati alcuni che potrebbero essere implicati nei meccanismi di controllo dei patogeni. La consociazione con salvia non ha modificato la produttività e la capacità vegetativa delle viti. I riscontri sperimentali aprono la strada ad investigazioni future che potranno avere come oggetto di ricerca non solo la consociazione con altre piante aromatiche officinali ma, più in generale, la biodiversità funzionale dei sistemi agrari, che è la strada per abbattere la dipendenza dai pesticidi.
25
Azeredo, Antonio. "Determinação de benzo(a) pireno em pescados comercializados em Campinas-SP." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254999.
Full textAbstract:
Orientador : Maria Cecilia de Figueiredo ToledoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-07-27T22:01:59Z (GMT). No. of bitstreams: 1 Azeredo_Antonio_M.pdf: 1864873 bytes, checksum: 56f9b654732a9202de6eae08d42b64af (MD5) Previous issue date: 2001
Resumo: Hidrocarbonetos policíclicos aromáticos (HPAs), entre os quais o benzo(a)pireno (B[a]P) é um doa mais estudados, são contaminates formados pela pirólise incompleta da matéria orgânica tecnológicos. Estes compostos estão presentes no meio ambiente e nos alimentos e caracterizam-se por apresentarem elevada toxicidade
Abstract: Polycyclic aromatic hydrocarbons (PAHs), including benzo (a) pyrene (B [a] P) is a donates most studied, are incomplete Contaminat formed by pyrolysis of organic material technology. These compounds are present in the environment and in foods and are characterized by high toxicity present
Mestrado
Mestre em Ciência de Alimentos
26
Müller, Britta Katrin [Verfasser]. "Systems biological investigation of aerobic and anaerobic aromatic catabolism in the bacterium Aromatoleum aromaticum EbN1 / Britta Katrin Müller." Braunschweig : Technische Universität Braunschweig, 2016. http://d-nb.info/1175818380/34.
Full text
27
Landera, Alexander. "Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polcyclic Aromatic Compounds in Titan's Atmosphere, the Interstellar Medium and Combustion." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/991.
Full textAbstract:
Several different mechanisms leading to the formation of (substituted) naphthalene and azanaphthalenes were examined using theoretical quantum chemical calculations. As a result, a series of novel synthetic routes to Polycyclic Aromatic Hydrocarbons (PAHs) and Nitrogen Containing Polycyclic Aromatic Compounds (N-PACs) have been proposed. On Earth, these aromatic compounds originate from incomplete combustion and are released into our environment, where they are known to be major pollutants, often with carcinogenic properties. In the atmosphere of a Saturn’s moon Titan, these PAH and N-PACs are believed to play a critical role in organic haze formation, as well as acting as chemical precursors to biologically relevant molecules. The theoretical calculations were performed by employing the ab initio G3(MP2,CC)/B3LYP/6-311G** method to effectively probe the Potential Energy Surfaces (PES) relevant to the PAH and N-PAC formation. Following the construction of the PES, Rice-Ramsperger-Kassel-Markus (RRKM) theory was used to evaluate all unimolecular rate constants as a function of collision energy under single-collision conditions. Branching ratios were then evaluated by solving phenomenological rate expressions for the various product concentrations. The most viable pathways to PAH and N-PAC formation were found to be those where the initial attack by the ethynyl (C2H) or cyano (CN) radical toward a unsaturated hydrocarbon molecule led to the formation of an intermediate which could not effectively lose a hydrogen atom. It is not until ring cyclization has occurred, that hydrogen elimination leads to a closed shell product. By quenching the possibility of the initial hydrogen atom elimination, one of the most competitive processes preventing the PAH or N-PAC formation was avoided, and the PAH or N-PAC formation was allowed to proceed. It is concluded that these considerations should be taken into account when attempting to explore any other potential routes towards aromatic compounds in cold environments, such as on Titan or in the interstellar medium.
28
Miller, Robert William. "Tetrabenzo[8]circulene: Synthesis and Structural Properties of Polycyclic Aromatic Hydrocarbons with Negative Curvature." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/792.
Full textAbstract:
Contorted polycyclic aromatic hydrocarbons have found increasing utility in the application of molecular electronics due to the surpamolecular properties that result from these non-planar structures. The [n]circulene series of molecules are particularly attractive members of the contorted aromatic family due to the unique structural implications that result from their changing value of n. For example, when n ≤ 5, the structures adopt a bowl-like shape; when n = 6, a planar structure is observed; and when 7 ≤ n ≤ 16, the compounds assume a saddle-like shape. Very few molecules exhibit the structural contortions that these contorted aromatics do – primarily because aromatic molecules desire to adopt highly planar conformations.
Following the model of aromaticity developed by Erich Clar, we set our sights on the synthesis of tetrabenzo[8]circulene, the stabilized form of [8]circulene established through the addition of four fused benzenoid rings around the periphery of the molecule. The initial approach towards this structure employs a Diels-Alder [4 + 2] cycloaddition reaction and a palladium catalyzed arylation reaction as the key transformation steps. The results of these studies were promising, establishing the structural characterization of this new molecule and providing access to functionalized derivatives of the saddle-shaped structure. However, access towards these functionalized derivatives proved limiting, compelling us to investigate alternative synthetic methodologies.
In the course of our studies, we established a new methodology towards 2,5-diarylthiophene-1-oxides, a key precursor to the Diels-Alder cycloaddition reaction. These reactive dienes are prepared from readily available arylacetylene precursors via zirconacyclopentadiene intermediates. The isolated yields of the desired thiophene-1-oxides are comparable to those obtained from previously established oxidation strategies while avoiding the formation of over-oxidation products. Of significant importance to scope of our work, this newly established methodology offers broader versatility providing products outfitted with electron-donating or electron-withdrawing groups.
These new methodologies provided access to functionalized derivatives of the saddle-shaped molecule tetrabenzo[8]circulene in improved yield when coupled with a revised Diels-Alder/oxidative cyclodehydrogenation approach. This methodology affords products containing both electron-rich and electron-poor functional groups in a more efficient manner. The optoelectronic effects that result from the introduction of this functionality and investigations into the development of larger contorted aromatic systems are also discussed.
29
Dainty, Richard Frank. "Aromatic annulations." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242247.
Full text
30
Santos, Ligia Gibini dos. "Utilização de consórcio bacteriano para biodegradação de hidrocarbonetos aromáticos policíclicos em solo." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254773.
Full textAbstract:
Orientador: Lucia Regina Durrant, Matthew James GrossmanDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-22T02:43:16Z (GMT). No. of bitstreams: 1 Santos_LigiaGibinidos_M.pdf: 3848321 bytes, checksum: 46f91a01a783f6fd7d5153ba73c6e8a0 (MD5) Previous issue date: 2013
Resumo: Dentre os contaminantes ambientais mais abundantes, destacam-se os Hidrocarbonetos aromáticos policíclicos (HAPs), que apresentam elevado potencial tóxico, sendo imprescindível sua remoção do ambiente. O objetivo deste trabalho foi analisar, em microcosmos, a biodegradação de HAPs por um consórcio bacteriano e identificar fatores que influenciam nesta degradação e na análise dos dados. A degradação dos HAPs no solo sem histórico de contaminação foi muito semelhante em todos os microcosmos, apresentando uma porcentagem de aproximadamente 85%. Para analisar a toxicidade do solo antes e depois da biorremediação, realizou-se um testes de germinação de sementes de Lactuca sativa (alface). O teste mostrou baixa toxicidade do solo após 80 dias da contaminação, com ou sem a adição do consórcio. Durante estudos de remediação biológica, é necessário utilizar um marcador interno para minimizar a dispersão e extração irregulares dos contaminantes. Neste estudo foi utilizado o hexaclorobenzeno, que mostrou excelente, uma vez que não sofreu nenhum tipo de degradação. Análises moleculares mostram que a adição de HAPs alterou significativamente a comunidade microbiana, favorecendo os membros degradadores de tais poluentes. O consórcio adicionado inibiu o crescimento de alguns micro-organismos autóctones. Além disso, não houveram evidências de que os micro-organismos degradadores de HAPs adicionados persistiram, sugerindo que eles podem não competir eficientemente com a população microbiana autóctone. Não houve efeito claramente identificado do hexaclorobenzeno sobre o crescimento de micro-organismos, com exceção de um aumento no número de organismos pertencentes da classe Alphaproteobacteria
Abstract: Polycyclic aromatic hydrocarbons (PAHs) stand out as among the most abundant and toxic of environmental contaminants, and their removal from contaminated sites is indispensable for a healthy environment. The objective of this study was to analyze, in soil microcosms, the biodegradation of PAHs by a bacterial PAH degrading consortium and identify factors that influence this degradation and data analysis. Degradation of PAHs in soil with no history of contamination was very similar in microcosms with or without bioaugmentation, with the extent of PAH removal of about 85% in all cases. The germination of Lactuca sativa (lettuce) in soils taken from the microcosms was used to examine the toxicity of the soil before and after bioremediation. The test showed a low toxicity of the soil 80 days after PAH contamination, with or without the addition of the consortium. During studies of biological remediation it is necessary to use an internal non-biodegradable marker to minimize the effect of uneven dispersion and irregular extraction of pollutants. This study used hexachlorobenzene as the nonbiodegradable marker and it proved to be an excellent marker as it did not suffer any significant degradation in the soil microcosms. Molecular analyzes showed that the addition of PAHs significantly altered the microbial community by encouraging the growth of PAH degraders. In addition, the added microbial consortium was found to inhibit the growth of some of the indigenous microorganisms. Furthermore, there was no evidence that the added PAH degraders persisted, suggesting that they might not compete effectively with the native microbial population. There was little effect of hexachlorobenzene on the microbial community or on the removal of the PAH contaminants, with the exception of an increase in the number of organisms belonging to the class Alphaproteobacteria
Mestrado
Ciência de Alimentos
Mestra em Ciência de Alimentos
31
Clough, Robert Steven. "The synthesis of aromatic polyethers by aromatic nucleophilic substitution." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1057072167.
Full text
32
Tfouni, Silvia Amelia Verdiani. "Estudo do efeito do processamento na contaminação de cana-de-açucar e derivados por hidrocarbonetos policiclicos aromaticos." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254996.
Full textAbstract:
Orientador: Maria Cecilia de Figueiredo ToledoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-05T13:48:10Z (GMT). No. of bitstreams: 1 Tfouni_SilviaAmeliaVerdiani_D.pdf: 392240 bytes, checksum: 6b63e5c3f72ce75847b3087c1e16bbe8 (MD5) Previous issue date: 2005
Doutorado
Ciência de Alimentos
Doutor em Ciência de Alimentos
33
Laws, Andrew Peter. "The quantitative electrophilic aromatic reactivity of some novel aromatic compounds." Thesis, University of Sussex, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328304.
Full text
34
Martyn, R. J. "Ipso aromatic substitution." Thesis, University of Canterbury. Chemistry, 1985. http://hdl.handle.net/10092/7318.
Full textAbstract:
In the first part of this thesis the conformation and stereochemistry of a number of polychlorocyclohex-3-enones, formed by the reaction of chlorine in acetic acid and hydrochloric acid with polysubstituted phenols (or anilines), are discussed. Those polychlorocyclohex-3-enones with the H(Cl)CS or the Me(Cl)CS structural features were shown to exist in a twist-boat conformation with the CS-Cl bond in the flagpole orientation. In contrast, two polychlorocyclohex-3-enones with gem-dichloro substituents at C5, were shown to be conformationally mobile in solution. The alicyclic ring of two 4,4,5-trichlorocyclohex-2-enones were also shown to exist in twist-boat conformations, but with the CS-Cl bond in the equatorial orientation. A satisfactory correlation between the ¹H n.m.r. and infrared spectroscopic data and the known structures in the solid state indicates that these polychlorocyclohex-3-enones and polychlorocyclohex-2-enones adopt conformations in solution close to those observed in the solid state.
Extensive use of single-crystal X-ray structure analysis was made in the above structural studies; some thirteen structure analyses are reported in this thesis.
In the second part of this thesis are discussed the reactions of polysubstituted 2-methylphenols with chlorine in carbon tetrachloride in the presence of pyridine to give
6-chloro-6-methylcyclohexa-2,4-dienones. These 6-chloro-6-methylcyclohexa-2,4-dienones arise from ipso chlorine attack on the phenol ortho to the hydroxy function. It was shown that attack ipso to a methyl group occurred in preference to attack ipso to a chlorine atom. Where both ortho positions of the phenolic substrate are methyl substituted, the site of ipso chlorine attack is affected by the meta substituents.
In the third part of this thesis the additions of chlorine to 6-chloro-6-methylcyclohexa-2,4-dienones to give polychlorocyclohex-3-enones and polychlorocyclohex-2-enones are discussed. These addition reactions proceed by three distinct reaction mechanisms, 2,3-, 4,5- and 2,5-chlorine addition. The 2,3-chlorine addition reaction was shown to be powerfully acid-catalysed. In contrast, the 4,5- and 2,5-chlorine additions were shown to be only mildly acid-catalysed. Reaction mechanisms which accommodate these observations are discussed.
Finally, the formation of an acyclic pentachloro hex-3-enoic acid by the chlorination of 4-chloro-2-methyl-6-nitrophenol (130) in acetic acid and hydrochloric acid is described and a probable mode of formation suggested.
35
Ferguson, Jayne Louise. "Colossal Aromatic Molecules." Thesis, University of Canterbury. Chemistry, 2013. http://hdl.handle.net/10092/8108.
Full textAbstract:
This thesis describes the preparation of a series of compounds containing π-excessive, five-membered, heterocyclic rings with peripheral aryl substituents, designed to investigate their oxidative cyclodehydrogenation and/or photocyclisation to form curved, fused aromatic systems with a heterocyclic atom at the core of the compound. The ability of these compounds to undergo oxidative cyclodehydrogenation was investigated using a range of conditions, including the use of Lewis acidic transition metals, organic reagents and light as catalysts to carry out the desired carbon-carbon bond forming reactions. Two backbone linked 2,2’-biimidazole ligands were prepared to investigate their coordination chemistry with a range of different metal ions and counter ions.
Two families of model compounds, including ten previously unreported compounds, were prepared and subjected to various conditions for oxidative cyclodehydrogenation and photocyclisation resulting in the isolation of compounds with one carbon-carbon bond formed between the peripheral aryl rings in the same position on the heterocyclic ring, nineteen previously unreported compounds were isolated. Additionally, in one case oxidative cyclodehydrogenation resulted in the formation of two carbon-carbon bonds, producing a highly strained aromatic compound containing a heterocyclic ring. Photocyclisation of one family of compounds resulted in the formation of a different heterocyclic core dependent upon the substituent on the nitrogen atom. Five pentaarylpyrrole compounds, three of which were previously unreported, were also prepared after the exploration of various synthetic routes towards the pentaarylpyrrole motif. Photocyclisation also resulted in the formation of one carbon-carbon bond. The compounds resulting from oxidative cyclodehydrogenation and photocyclisation were characterised by NMR spectroscopy, UV/vis spectroscopy and fluorometry, where possible X-ray crystallography was also used.
The coordination chemistry of backbone linked 2,2’-biimidazole ligands to various metal ions could be controlled by the length of the backbone linker. The ethyl linked 2,2’-biimidazole ligand formed bridging and monodentate coordination compounds with various metal ions, the metallosupramolecular assemblies produced with silver ions could be controlled by the anion present. Discrete coordination complexes were usually formed, but in two cases metallopolymers were produced. The propyl linked 2,2’-biimidazole ligand formed exclusively discrete, chelating complexes with copper (II) metal ions. Eighteen coordination complexes were prepared during the course of this study characterized by X-ray crystallography, and NMR spectroscopy where appropriate.
36
Thompson, Claire. "Aromatic nucleophilic nitration." Thesis, University of Exeter, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390199.
Full text
37
Pamplona, Maria Teresa Troina. "Aromatic nitrogen mustards." Thesis, Open University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385254.
Full text
38
Diorazio, Louis Joseph. "New aromatic fluorinations." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46746.
Full text
39
Magrini, Mariana Juventina 1985. "Degradação de HPAs e produção de enzimas ligninolíticas por fungos basidiomicetos derivados de esponjas marinhas." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316913.
Full textAbstract:
Orientadores: Lara Durães Sette, Rafaella Costa Bonugli SantosDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-21T03:33:56Z (GMT). No. of bitstreams: 1 Magrini_MarianaJuventina_M.pdf: 1731882 bytes, checksum: 2aac64c24012708e8272f0954e438112 (MD5) Previous issue date: 2012
Resumo: Hidrocarbonetos Policíclicos Aromáticos (HPAs) são poluentes ambientais oriundos de fontes naturais e antropogênicas, caracterizados por suas propriedades mutagênicas e carcinogênicas e persistência no ambiente. Fungos basidiomicetos de degradação branca têm sido extensivamente estudados devido à sua habilidade em degradar uma ampla variedade de compostos xenobióticos por meio do sistema ligninolítico, composto por enzimas de baixa especificidade ao substrato, como as Lacases, Manganês peroxidases (MnP) e Lignina peroxidases (LiP). Considerando que os estudos relacionados à degradação de poluentes por fungos marinhos ainda são escassos, o presente trabalho visou à avaliação da degradação dos HPAs pireno e BaP e da atividade ligninolítica de três basidiomicetos isolados de esponjas marinhas. Durante a etapa de seleção do fungo mais eficiente, os três basidiomicetos foram capazes de degradar os HPAs (0,02 e 0,04 mg mL-1 de BaP e pireno, respectivamente) após 7, 14 e 21 dias de incubação, apresentando atividade ligninolítica, sobretudo de Lacase, que possui uma ampla aplicação tecnológica. O fungo Marasmiellus sp. CBMAI 1062 degradou mais de 90% da quantidade inicial de ambos os HPAs após 7 dias de incubação. O crescimento dos basidiomicetos não foi influenciado pelos HPAs, com exceção do Marasmiellus sp. CBMAI 1062, que apresentou maior crescimento micelial em presença dos mesmos. A atividade ligninolítica não apresentou correlação com a degradação nem com o crescimento micelial, para todos os basidiomicetos estudados. Entretanto, os resultados sugerem que na presença dos HPAs pode ter havido indução da produção das enzimas Lacase e MnP. O fungo Marasmiellus sp. CBMAI 1062 foi selecionado para as etapas posteriores devido a sua produção enzimática, crescimento em presença dos HPAs e altas porcentagens de degradação. Após 7 dias de cultivo em presença dos HPAs em meio mineral, este fungo apresentou atividade das enzimas LiP, MnP e Lacase, elevadas taxas de degradação (79,9% de pireno e 95,2% de BaP) e aumento de biomassa, o que sugere o consumo, ao menos em parte, dos HPAs e/ou de seus produtos de degradação como fontes de carbono e energia. Nos experimentos de análise qualitativa de metabólitos formados, foram identificados quatro metabólitos: 1-hidroxipireno, pireno dihidrodiol e dihidroxipireno, derivados da degradação do pireno, e hidroxibenzo[a]pireno, derivado da degradação do BaP. Tais compostos sugerem a degradação dos HPAs via sistema enzimático CYP e epóxido hidrolases. Elevadas porcentagens de degradação foram obtidas em meio com 35 ppm (3,5%) de salinidade e pH 9,0. Contudo, nestas condições, a atividade ligninolítica de Lacase, LiP e MnP foi ausente. O aumento da concentração dos HPAs não diminuiu as taxas de degradação nem o crescimento micelial. De modo geral, as maiores porcentagens de degradação foram alcançadas sob elevada concentração de nutrientes. Através dos experimentos de degradação de BaP, foi possível propor um modelo matemático derivado da regressão múltipla do Delineamento Composto Central Rotacional (DCCR) para dois fatores. Os resultados do presente trabalho evidenciam o potencial do fungo Marasmiellus sp. CBMAI 1062 para remediação de ambientes salinos e/ou alcalinos bem como para a aplicação biotecnológica de suas enzimas ligninolíticas
Abstract: Polycyclic Aromatic Hydrocarbons (PAHs) are environmental pollutants from natural and anthropogenic sources, characterized by their mutagenic and carcinogenic properties and persistence in the environment. White-rot basidiomycetes have been extensively studied due to the ability to degrade a wide variety of xenobiotic compounds using their ligninolytic system, constituted by enzymes with low substrate specificity, such as Laccases, Manganese peroxidase (MnP) and Lignin peroxidases (LiP). Since the studies related to the degradation of pollutants by marine-derived fungi are scarce, the present study aimed to evaluate the degradation of PAHs pyrene and BaP and the ligninolytic activity of three basidiomycetes isolated from marine sponges. During the selection of the most efficient fungus, the three basidiomycetes were able to degrade PAHs (0.02 to 0.04 mg mL-1 BaP and pyrene, respectively) after 7, 14 and 21 days of incubation, presenting ligninolytic activity, especially Laccase, which has a wide technological application. The fungus Marasmiellus sp. CBMAI 1062 degraded more than 90% of the initial amount of both PAHs after 7 days of incubation. The growth of basidiomycetes was not affected by PAHs, except Marasmiellus sp. CBMAI 1062, which showed the highest mycelial growth in their presence. The ligninolytic activity was not correlated with the degradation nor with the mycelial growth, for all basidiomycetes studied. However, the results suggest that the presence of PAHs may have induced the Laccase and MnP production. Marasmiellus sp. CBMAI 1062 was selected for the subsequent assays due to its enzyme production, growth in the presence of PAHs and high degradation rates. After 7 days of growth in the presence of PAHs in mineral medium, this fungus showed activity of LiP, MnP and Laccase, high degradation rates (79.9% of pirene and 95.2% of BaP) and increased biomass, suggesting consumption, at least in part, of PAHs and/or their degradation products as carbon and energy sources. In qualitative analysis of the metabolites produced, four metabolites were identified: 1-hydroxypyrene, pyrene dihydrodiol and dihydroxypyrene, derived from the pyrene degradation, and hydroxybenzo[a]pyrene derived from BaP degradation. Such compounds suggest PAHs degradation via CYP enzyme system and epoxide hydrolases. High degradation percentages were obtained in medium with 35 ppt salinity (3.5%) and pH 9.0. However, under these conditions, the activity of ligninolytic Laccase, LiP and MnP was absent. Increasing the concentration of PAHs has not decreased rates of degradation or mycelial growth. In general, the major degradation percentages were achieved at higher nutrient concentration. Through the degradation of BaP assays, was possible to propose a mathematical model derived from multiple regression Central Composite Rotatable Design (CCRD) with two factors. The results of this study highlight the potential of fungus Marasmiellus sp. CBMAI 1062 for remediation of saline and/or alkali environments as well as for biotechnological application of their ligninolytic enzymes
Mestrado
Microbiologia
Mestre em Genética e Biologia Molecular
40
Allinson, Graeme. "Non-Kekulé polynuclear aromatics." Thesis, University of Leeds, 1991. http://etheses.whiterose.ac.uk/15209/.
Full text
41
Poudel, Pramod Prasad. "NOVEL AROMATIC ION–PAIRS: SYNERGY BETWEEN ELECTROSTATICS AND Π-FACE AROMATIC INTERACTIONS." UKnowledge, 2012. http://uknowledge.uky.edu/chemistry_etds/4.
Full textAbstract:
This dissertation focuses on the design and study of charged aromatic molecules where weak π-π interactions synergize with electrostatic interactions to enhance the overall interaction between aromatic moieties. Each chapter investigates some aspect of this hypothetical synergy between electrostatics and π-face aromatic cohesion.
The first chapter unveiled the importance of electrostatics in the intramolecular stacking of flexible aromatic molecular templates 1-2Br and 2a. While our previous studies found dicationic molecular template 1-2Br to have intramolecular π-stacking between electron poor pyridinium and electron rich xylylene moieties, no such stacking interaction was observed in the neutral analog 2a.
Chapter two systematically explored the stacking pattern of electron poor aromatics in the form of oxygen- and / or nitrogen- substituted triangulenium cations, [1(NR)3]+ and [1(O)3(OH)3]+. As indicated in the chemical literature, triazatriangulenium cations [1(NR)3]+ with N- ethyl (and longer alkyl chains) chains were found to pack as face-to-face dimers. This study found the formation of columnar, face-to-face, n-meric association between aromatic cations in the structures with decreased steric interactions of the side chains in the stacking planes ([1(NMe)3]+ and [1(O)3(OH)3]+). Similar iso-structural triangulene based aromatic anions, (2)- and (3)2- didn’t indicate any facial interactions in the solid states.
The possible synergy between unit charge electrostatics and π-face aromatic interactions was explored in aromatic ion pairs 1•2 of triangulene based aromatic cations and aromatic anions. This charge-assisted π-π stacking seems to be the novel way of getting strong π-system interactions where the strongest non-covalent force and the weakest non-covalent force: ionic bonding and π-stacking respectively synergize together. The π-π interaction between ionic aromatics in the solid state was investigated by means of single crystal x-ray diffraction and powder x-ray diffraction (PXRD). The interaction in the solution state was examined by UV-Vis spectroscopy, electrospray ionization mass spectroscopy (ESI-MS) and electrochemical studies. Studies found that optimal synergy was possible only in the ion pairs with no steric interactions of alkyl (or aryl) side chains in the stacking planes (1(O)3•2 & 1(NMe)3•2) and the interaction was found to be comparable with the strongest radical-assisted π-stacking described in the chemical literature.
42
Reid, Matthew. "The calculation of proton chemical shifts in aromatics, carbonitriles, acetylenes and hetero-aromatics." Thesis, University of Liverpool, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250595.
Full text
43
Myers, Eddie Leonard. "Heterocyclic aromatic nucleic acids." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79056.
Full textAbstract:
In order to investigate the role played by the aromatic moiety of Aromatic Peptide Nucleic Acids (APNAs) in their ability to hybridize with RNA and DNA, as well as improve the solubility of APNA oligomers in aqueous solutions, a new generation of heterocyclic monomers were designed. APNA monomers, where the nucleobase can be thymine, cytosine adenine or guanine, with backbones contain thiophene and pyridine moieties were synthesized. Suitably protected APNA-APNA and PNA-APNA dimers were also synthesized as building blocks for the solid phase synthesis of APNA-PNA chimeras and APNA homopolymers. Due to the instability of the pyridine-containing APNA oligomers to the harsh acidic conditions required to cleave oligomers from the MBHA resin, a new protocol was developed for the synthesis of these molecules on the trityl chloride resin. Oligomers of PNA and APNA-PNA chimeras were successfully synthesized on this solid support, and cleaved from the resin using mild acidic conditions.
44
Lancaster, Norman Llewellyn. "Solid-supported aromatic nitrations." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302641.
Full textAbstract:
The efficacy of the claycop system in the nitration and the dinitration of toluene has been investigated.Comparison of regioselectivity and of rate constant with homogeneous nitric acid nitration was made. The use of ion-exchanged montmorillonite clay as a catalyst for acetyl nitrate nitration was studied. The system was found to enhance Para selectivity in the nitration of toluene and to catalyse the reaction. Additionally, the catalyst was shown to be recyclable. The reaction of toluene was too fast to allow kinetic study. However, kinetic study was possible,using chlorobenzene as substrate.Again, the system was found to decrease both the reaction time and the o-/ p- ratio. It was possible to demonstrate a dependence of rate constant upon mass of clay. The effect of the counter ion was investigated and the use of trifluoroacetyl anhydride was studied. A new system for aromatic nitration has been developed in this work using zeolite with dinitrogenp entoxide.A series of zeolites were screened in the nitration of onitrotoluene, with the H-faujasites showing the quickest reaction times and highest degree of regioselectivity. The silica/ alumina ratio of the faujasite used was varied and this was shown to have an effect on regioselectivity. However, reactions were too fast for kinetic study. The faujasite/ dinitrogen pentoxide system was used in the nitration of some deactivated benzenes using these substrates allowed kinetic studies to be made and the order in each component to be determined. It was found that nitration was zeroth order in dinitrogen pentoxide, that the reaction obeyed a first order rate law, and that the first order rate constant was proportional to the mass of zeolite used. Comparison of the relative rates of nitration of 1-chloro-2-nitrobenzene1, -chloro-4-nitrobenzene and nitrobenzeneb y this system to the relative rate constants of nitronium ion nitration was made. The similarity suggested that the mechanism of nitration by faujasite/d initrogen pentoxide might involve nitronium ion transfer.Amongst the H-faujasites of different silica/ alumina ratio, the rate constant was shown to increase with the aluminium content. A mechanism is proposed in which zeolite protons (present in proportion to the aluminium atoms) are first replaced by nitronium ions. The latter are transferred to the aromatic in the rate-determining step. The use of non-chlorinated solvents and the recycling of zeolite were both studied, and the nitration of 2,6-dinitrotoluene was attempted. The use of the faujasite/ dinitrogen pentoxide system was extended to the nitration of nitrogen containing aromatic heterocycles direct C-nitration of quinolone was not possible, only N-nitration. However, pyrazole was converted to 1,4-dinitropyrazole quickly and cleanly under mild conditions. It was shown that the N-nitration occurred instantly, followed by slower C-nitration. The kinetics of the second nitration were studied and comparison with deactivated benzenes was made.
45
Marczylo, Timothy Hywel. "Bioactivation of aromatic amines." Thesis, University of Surrey, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336523.
Full text
46
Magron, Corinne. "Perfluoroalkylation of aromatic systems." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/4634/.
Full textAbstract:
I. We have concentrated on the synthesis of aromatic systems containing CH(_2)R(_F) groups, where R(_F) is a bulky group derived from hexafluoropropene dimer, using fluoride ion induced methodology. A variety of procedures have been explored and methods of synthesis are described. We have made a major advance in this area by the simple expedient of extracting the polyfluoroalkylated products directly into commercially available perfluorinated fluids: FC-84 (bp 8O C), enabling simple purification. II. This new class of perfluoroalkylated derivatives has allowed us to explore some further chemistry. Synthesis and reactions are presented and the results are discussed in terms of electronic effects of the perfluoroalkyl group on the benzene ring. The unusual miscibility properties of fluorocarbon solvents have also prompted us to investigate the potential utility of these systems for dyes and catalysis. III. Synthetically useful perfluoroalkylated-s-triazines have been synthesised from 2,4,6-trifluoro-s-triazine, by fluoride ion induced reaction with hexafluoropropene. These systems so produced were extensively studied, and particular attention was paid to reactions with oxygen-centered nucleophiles. Model chemistry to demonstrate that attachment of perfluorocarbon groups to surfaces could be a useful form of treatment by using this methodology and was explored.
47
Tian, Zhenjiao. "Oxidation and Reduction Process for Polycyclic Aromatic Hydrocarbons and Nitrated Polycyclic Aromatic Hydrocarbons." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1228333650.
Full text
48
Troche, Karla Souza. "Estudo da atividade carcinogênica dos hidrocarbonetos policíclicos aromáticos através de descritores quânticos." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277650.
Full textAbstract:
Orientador: Douglas Soares GalvãoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
Made available in DSpace on 2018-09-27T13:47:49Z (GMT). No. of bitstreams: 1 Troche_KarlaSouza_M.pdf: 1255427 bytes, checksum: 17251baf9cd0c68ce5c4f8e8adefec0b (MD5) Previous issue date: 2003
Resumo: Neste trabalho apresentamos estudos de estrutura-atividade realizados para 81 hidrocarbonetos policíclicos aromáticos (PAHs) tentando identificar compostos carcinogênicos. Em particular, empregamos uma nova metodologia desenvolvida para tratar o problema da correlação estrutura geométrica com atividade biológica, denominada Metodologia de Índices Eletrônicos (MIE). Utilizamos três métodos semi-empíricos para estudar a dependência entre a qualidade dos resultados obtidos pela MIE e o Hamiltoniano utilizado. Para validarmos os descritores utilizados pela MIE, investigamos a relação entre a atividade experimental dos PAHs e descritores teóricos através de cinco metodologias de reconhecimento de padrões: a Análise de Componentes Principais (PCA), Análise Hierárquica de Agrupamentos (HCA), K-ésimo vizinho mais próximo (KNN), Soft Independent Modeling of Class Analogies (SIMCA) e as Redes Neurais Artificiais (NN). Para estas investigações distintas pudemos correlacionar a atividade dos PAHs estudados com parâmetros teóricos, em sua maioria eletrônicos, onde os parâmetros utilizados na MIE foram selecionados pelos diferentes métodos. Este estudo valida estatisticamente a MIE como uma nova metodologia capaz de identificar compostos biologicamente ativos, e com um custo computacional menor que técnicas convencionais de Relação estrutura-atividade (SAR) e apresentando um desempenho, em geral superior
Abstract: In this work we present the study structure-activity realized for 81 polycyclic aromatic hydrocarbons (PAHs) trying to identify carcinogenic compounds. Particularly, we used a new methodology developed to deal with the problem of correlation between geometrical structure and biological activity, the Electronic Indices Methodology (EIM). We used three semi-empirical methods to analyze the dependence between the quality of results obtained through EIM and the Hamiltonian used. In order to validate the descriptors used in EIM, we investigated the relationship between the experimental activity of PAHs and the theorical descriptors through five methodologies of pattern recognition: Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), Kth Nearest Neighbor (KNN), Soft Independent Modeling of Class Analogies (SIMCA) and Neural Networks (NN). From these different investigations, we could correlate the activity of PAHs studied with theorical parameters, almost all electronic, where the used parameters on EIM were selected with the different methods. These studies validate the statistical value of electronic parameters derived from EIM analysis and their ability to identify active compounds. The EIM out performed more standard Structure-Activity Relationship (SAR) methodologies
Mestrado
Física da Matéria Condensada
Mestre em Física
49
Cosgrove, Sebastian Cronin. "Direct photochemical amination of aromatics." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/17796/.
Full textAbstract:
The formation of aromatic carbon to nitrogen bonds is one of the most important processes used in the chemical industry. It is prevalent in many biologically-relevant molecules such as pharmaceuticals and agrochemicals. A modified Hofmann-Löffler-Freytag reaction, which allowed the direct functionalisation of aromatic C-H bonds using N-haloamines under UV-irradiation in highly acidic media, was first reported by Bock et al. in 1965.1 The reported conditions used concentrated sulfuric acid as solvent and demonstrated a minimal substrate scope. Here, it has been shown that UV-irradiation of N-chloroamines with 10 equivalents of methanesulfonic acid in DCM allows for the intramolecular amination of unfunctionalised aryl C-H bonds to form tetrahydroquinolines. These novel conditions have been extended to 30 examples including in a concise synthesis of the alkaloid natural product angustureine. Furthermore, studies have helped elucidate a potential mechanism of the reaction and led to the discovery of a 1,2-alkyl migration reaction. The reaction has also been shown to work in a continuous photochemical reactor. This was extended to work in a two-stage reactor where amines were chlorinated and reacted in situ to form tetrahydroquinolines directly. Some of the substrates produced with the photochemical methodology have been tested in enzymatic deracemizations using genetically modified monoamine oxidase enzymes. Whilst modest activity was observed for a series of N-substituted tetrahydroquinolines, a group of natural products containing N-unsubstituted tetrahydroquinoline cores were successfully deracemized, with ee’s as high as 90% obtained.
50
Lewis, Zoe G. "Synthetic, spectroscopic and structural studies on carbametallaboranes containing aromatic and fused aromatic ring systems." Thesis, University of Edinburgh, 1991. http://hdl.handle.net/1842/15208.
Full textAbstract:
Chapter 1 gives an overview of carbaborane chemistry, including concepts of cluster bonding and slip distortions in carbametallaboranes derived from [7,8-nido-C2B9H11]2-. This is followed by an introduction to the transition metal chemistry of fused aromatic ligands, with specific reference to the similar bonding capabilities of these and carborane species. Finally, the structure of 3-(η5-C9H7)-3,1,2-closo-C2B9H11 (1) is discussed with rationalisation of the observed cisoid molecular conformation. Chapter 2 comprises two sections, A and B. Section A presents the syntheses and structures of three indenyl carbametallaboranes, 1-Ph-3-(η5-C9H7)-3,1,2-closoC2B9H10 (2), 1-(CH2OCH3)-3-(η5-C9H7)-3,1,2-closo-C2B9H10 (3) and 1,2-(CH2OCH3)2-3-(η5-C9H7)-3,1,2-closo-C2B9H9 (4). In 2 and 3 the indenyl ligand adopts a conformation analogous to that in 1, i.e. the indenyl ring junction carbon atoms are cisoid with respect to the cage carbon atoms. In 4 the presence of two ether substituents has resulted in the adoption of the 'next best' staggered conformation. A series of EHMO calculations performed on idealized models of 1-4 predict theoretical energy minimum conformations in broad agreement with those observed crystallographically. Section B describes the synthesis and structural determination of the first reported fluorenyl carbametallaborane complex, 3-(η5-C13H9)-3,1,2-closo-C2B9H11 (5). The molecular conformation has been rationalised in terms of the trans influence of the facial cage boron atoms, and is in full accord with that predicted by the results of EHMO calculations on an idealised model of 5.