1,720,956 research outputs found
Extraction of bioactive molecules from sea waste
No full textThis thesis focuses on the extraction of bioactive molecules from sea waste, aiming to explore the potential of these natural resources for applications in food products and pharmaceutical sectors. The study explored different perspectives on the topic, including nutritional characterizing, food security, innovative technologies and biodiversity.
First, we evaluated the effect of two immersion times (24 h and 18 h) on the growth, mortality, biochemical, and elemental composition of Ostrea edulis (O. edulis) and Magallana (Crassostrea) gigas (M. gigas), farmed using off-bottom methods in the “Valli di Comacchio” (Ferrara) from January to July 2023. While M. gigas showed no differences in final mass, O. edulis was affected by immersion time. Shell length was greater with 24 h immersion, but mortality increased with 18 h immersion only in O. edulis. Growth rates were highest in May for oysters immersed 24 h, likely due to warmer temperatures and better food availability.
Biochemical analysis showed O. edulis reared for 18 h had more saturated fatty acids, probably due to higher palmitic acid. Shell elemental composition varied, except for calcium and manganese. However, immersion time had limited effects on the edible part of the oysters. Both species reached commercial size in 6–7 months, confirming “Valli di Comacchio” as a promising farming site. The study also highlights the importance of biodiversity conservation, particularly the protection of native species O. edulis. Further research focused on O. edulis quality across seasons. Nutritional and antioxidant properties, carotenoids, and contaminants were analyzed in winter, summer, and autumn. Proteins, EPA, DHA, and amino acids reached the maximum in winter, while oleic acid, lysine, and magnesium were highest in summer. Lipids and carbohydrates were more abundant in autumn. Toxic metal levels were higher in winter, while polycyclic aromatic hydrocarbons appeared in summer and autumn. Monitoring these factors is essential for improving farming techniques and determining the best period for consumption.
In the second part of my thesis, we examine the initial insights into the biochemistry of Hermodice carunculata (H. carunculata) and the recovery of carotenoids using supercritical fluid extraction (SFE). Additionally, we evaluated the implication for HaCaT cell viability. The study demonstrated that H. carunculata is a valuable source of different nutritional compounds, such as proteins, lipids and carotenoids. Supercritical CO2-assisted extraction achieved the highest carotenoid recovery at 40°C, 25 MPa, 10% EtOH, and 75 min. Astaxanthin was the predominant carotenoid in H. carunculata extracts, with the highest concentration obtained at 40°C, 35 MPa, 4% EtOH, and 30 min. Additionally, certain concentrations of SFE extract show improved cell viability when tested on HaCaT cells, suggesting positive effects on proliferation could be exploited for cosmetic or regenerative medicine purposes.
In conclusion, the study of Ulva sp. highlights seasonal variations in its biochemical composition. Samples from the “Sacca di Goro” showed higher carbohydrates and protein levels than reported in other studies but lower total lipids and amino acids. Minerals, carotenoids, chlorophylls, and starch exhibited high variability. However, these variations are likely influenced by abiotic factors such as temperature, light intensity, nutrient availability, geographic location, pollution, and the biological condition of the algae. For this reason, generalisations about the composition of seaweed are of limited use. Due to these fluctuations, generalizing seaweed composition is challenging. However, this preliminary research on bioactive molecules and seasonality supports the integration of Ulva sp. into sustainable practices, helping manage biomass disposal while exploting its biochemical potential for industrial applications.Questa tesi si concentra sull'estrazione di molecole bioattive dai residui marini, con l'obiettivo di esplorare il potenziale di queste risorse naturali per applicazioni nel settore alimentare e farmaceutico. Lo studio ha analizzato diverse prospettive sul tema, tra cui la caratterizzazione nutrizionale, la sicurezza alimentare, le tecnologie innovative e la biodiversità. Abbiamo valutato l’effetto di due tempi di immersione (24 h e 18 h) sulla crescita, mortalità, composizione biochimica ed elementare di Ostrea edulis (O. edulis) e Magallana (Crassostrea) gigas (M. gigas), allevate in off-bottom nelle “Valli di Comacchio” (Ferrara) da Gennaio a Luglio 2023. Mentre M. gigas non ha mostrato differenze nella massa finale, O. edulis è stata influenzata dal tempo di immersione. La lunghezza del guscio era maggiore con 24 h di immersione, ma la mortalità aumentava con 18 h di immersione solo in O. edulis. Il tasso di crescita era massimo a Maggio per le ostriche immerse 24 h, probabilmente dovuto a temperature più alte e maggiore disponibilità di cibo. L’analisi biochimica ha mostrato che O. edulis allevata per 18 h aveva una maggiore percentuale di acidi grassi saturi, probabilmente a causa di un aumento dell’acido palmitico. La composizione elementare del guscio variava, ad eccezione di calcio e manganese. Tuttavia, il tempo di immersione ha avuto un impatto limitato sulla parte edibile delle ostriche. Entrambe le specie hanno raggiunto la taglia commerciale in 6-7 mesi, confermando le “Valli di Comacchio” come un sito promettente per l’allevamento di ostriche. Lo studio sottolinea inoltre l’importanza della conservazione della biodiversità, in particolare la protezione della specie autoctona O. edulis. Ulteriori ricerche hanno esaminato la qualità di O. edulis nelle diverse stagioni. Le proprietà nutrizionali e antiossidanti, i carotenoidi e i contaminanti sono stati analizzati in inverno, estate e autunno. Proteine, EPA, DHA e alcuni amminoacidi hanno raggiunto i livelli massimi in inverno, mentre l’acido oleico, la lisina e il magnesio erano più elevati in estate. Lipidi e carboidrati erano più abbondanti in autunno. I livelli di metalli tossici erano più alti in inverno, mentre gli idrocarburi policiclici aromatici erano presenti in estate e autunno.
La seconda parte della tesi ha esaminato la biochimica di Hermodice carunculata (H. carunculata) e il recupero di carotenoidi utilizzando l’estrazione con fluidi supercritici (SFE). Inoltre, è stato valutato l’effetto sulle cellule HaCaT, un modello cellulare per studi di tossicità e proliferazione. Lo studio ha dimostrato che H. carunculata è una fonte preziosa di composti nutrizionali, come proteine, lipidi e carotenoidi. L’estrazione con CO2 supercritica ha ottenuto il massimo recupero di carotenoidi a 40°C, 25 MPa, 10% EtOH e 75 min. L’astaxantina è risultata il carotenoide predominante, con la massima concentrazione a 40°C, 35 MPa, 4% EtOH e 30 min. Inoltre, alcune concentrazioni di estratti SFE hanno migliorato la vitalità cellulare negli HaCaT, suggerendo potenziali applicazioni in cosmetica e medicina rigenerativa.
Infine, lo studio ha analizzato le variazioni stagionali della composizione biochimica di Ulva sp. prelevata dalla Sacca di Goro. Rispetto ad altri studi, questi campioni presentavano livelli più elevati di carboidrati e proteine, ma quantità inferiori di lipidi totali e amminoacidi. Minerali, carotenoidi, clorofille e amido hanno mostrato un’elevata variabilità, probabilmente influenzata da fattori ambientali come temperatura, intensità luminosa, disponibilità di nutrienti, posizione geografica, inquinamento e stato biologico dell’alga.Tuttavia, questa ricerca preliminare sulle molecole bioattive e sulla stagionalità supporta l’integrazione di Ulva sp. in pratiche sostenibili, contribuendo alla gestione dei rifiuti biologici e sfruttandone il potenziale biochimico per applicazioni industriali
Comparative analysis of two different immersion times in the farming systems for Ostrea edulis and Magallana (Crassostrea) gigas in a brackish basin of Valli di Comacchio (northern Italy)
No full textEmersion/immersion conditions in off-bottom production of oysters is a promising approach to mitigate various specific challenges associated with aquaculture activities. The aim of this study has been to assess the effect of two different immersion times 24 h and 18 h on growth, mortality, biochemical and elemental composition of two species of oyster, reared in brackish basin of Valli di Comacchio (Ferrara, Emilia-Romagna, Italy). Juveniles of Ostrea edulis and Magallana (Crassostrea) gigas, were cultivated with off-bottom methods from January to July 2023. At the end of the trial, the mean individual mass presented the same data in M. gigas for both immersion time, unlike O. edulis. In the same period both oyster species, reared for 24 h in immersion exhibited higher shell length compared to those immersed for 18 h; while the mortality rate was greater for the 18 h immersion only for O. edulis. The daily growth rate of oysters immersed for 24 h showed a value three times higher in May, which can be attributed to an increase of temperature and consequently to food uptake. In summary, the biochemical analyses of the edible part showed significant differences for O. edulis and M. gigas. O. edulis reared for 18 h of immersion, had a higher percentage of saturated fatty acids than oysters reared for 24 h of immersion; probably due to an increase in palmitic one. The elemental composition of the shell showed no significant differences for calcium and manganese, while the other elements analyzed showed important differences between 24 h and 18 h for both species. In conclusion, immersion time O. edulis and M. gigas, had a limited impact on edible part of oysters, while the elemental composition of the shell presented some significantly (p < 0.05) differences. The data obtained suggest that of the use of the two immersion times, based on the growth phase of oyster, could be optimal for feed availability and maximal clearance rate. Moreover, the two oyster species reached the commercial size in 6–7 months with both immersion time, which makes Valli di Comacchio a promising site for oyster farming
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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