1,721,023 research outputs found
Coffee Assessment Using 1H NMR Spectroscopy and Multivariate Data Analysis: A Review
No full textThe importance of nuclear magnetic resonance (NMR) spectroscopy for the
food industry, including the coffee industry, has led to several studies using this
analytical tool to assess coffee in different scenarios. In this context, this chapter
presents an overview of 1H NMR-based metabolomics analysis used in coffee quality
control. Several articles using 1H NMR associated with multivariate data analysis have
been published to investigate aspects related to quality, authenticity, sensory quality,
production processes, and origin of coffee. In addition, the present review reports the
main chemical shifts of the constituents present in the extracts of green and roasted
coffee beans. The results presented confirm the potential and versatility of 1H NMR
combined with chemometric tools for coffee analysis, playing an important role in
distinguishing and identifying the origins, quality, and purity of coffee. Exploratory
data analysis, classification, and calibration are the most used chemometric methods in
metabolomics applied in the coffee field. The results show the potential of NMR and
multivariate data analysis for coffee authentication
GinExtraMed: NUOVA MEDICAZIONE ECOSOSTENIBILE E BIOCOMPATIBILE A BASE DI GINESTRA E ROSA CANINA L.
No full textLa gestione delle ferite ha un sostanziale impatto sul Sistema Sanitario Nazionale imponendo notevoli costi
alla società. Nonostante i recenti progressi nel settore del wound-care, il trattamento delle ferite rimane
ancora una sfida importante [1]. Inoltre, la crescente consapevolezza ecologica incentiva lo sviluppo di nuovi
prodotti per le medicazioni che siano sostenibili e a basso impatto ambientale [2]. Nel contesto dei prodotti
biorinnovabili, vantaggiosi per la salute ed environmental friendly, la fibra di ginestra risulta una valida alter nativa all’utilizzo del cotone per la preparazione di medicazioni per il trattamento delle ferite. A differenza
del cotone, la ginestra (Spartium jiunceum L.) cresce spontaneamente in tutti i paesi dell’area mediterranea;
la sua coltivazione non richiede concimi, pesticidi e diserbanti ed oltretutto può essere coltivata in terreni
non adatti a coltivazioni alimentari [3].
L’obiettivo di questo lavoro è quello di sviluppare una medicazione innovativa, ecosostenibile e biocompati bile per il trattamento delle ferite superficiali e delle lesioni della cute. Le medicazioni in fibra di ginestra sono
state impregnate con l’estratto idroalcolico di Rosa canina L., incapsulato in sistemi vescicolari in grado di
proteggerlo e migliorarne la propria attività. La Rosa canina L. è conosciuta fin dai tempi antichi per il suo
alto contenuto di acido ascorbico e per le sue proprietà antiossidanti e antiinfiammatorie [2].
L’estratto idroalcolico è stato incapsulato in sistemi vescicolari, glicetosomi, preparati con il metodo solvent
injection e caratterizzati in termini di dimensioni, potenziale ζ ed efficienza di incapsulazione. Sono stati
eseguiti, inoltre, gli studi di rilascio in vitro ed è stata valutata la stabilità nel tempo. La biocompatibilità delle
medicazioni in fibra di ginestra impregnate con i glicetosomi è stata valutata sulla linea cellulare WS1 (fibro blasti di derma umano). Infine, è stata valutata la capacità di cicatrizzazione delle medicazioni mediante lo
scratch test.
I risultati ottenuti hanno dimostrato che i glicetosomi carichi di estratto di Rosa canina L. hanno dimensioni
nanometriche (150- 250 nm), potenziale ζ negativo e un’alta efficienza di incapsulazione (~ 90%). Tali si stemi vescicolari sono, inoltre, stabili e biocompatibili. Infine, le cellule trattate con le medicazioni impregnate
con i glicetosomi carichi di estratto mostrano una significativa riduzione dei tempi di chiusura della ferita. In
conclusione, sulla base dei risultati ottenuti, la medicazione GinExtraMed potrebbe rappresentare un inte ressante alternativa alla garza di cotone per il trattamento delle ferite superficiali
Analysis of Artemisia annua extracts and related products by high performance liquid chromatography-tandem mass spectrometry coupled to sample treatment miniaturisation
Full text linkArtemisinin, the main antimalarial compound of Artemisia annua L., is currently attracting increasing interest for its antiproliferative properties, but its content is highly variable, depending on several genetic, environmental and processing conditions. Aim of the present study is to analyse the artemisinin content in different plant extracts, to test their in vitro activity on cell proliferation and then to correlate these data to the active principle concentration. For this purpose, an innovative miniaturised sample pretreatment strategy based on microextraction by packed sorbent (MEPS) was developed and coupled to an original advanced method based on liquid chromatography with diode array detection and tandem mass spectrometry (LC-DAD-MS/MS). The method was fully validated, granting consistent data. Good linearity was found over a suitable concentration range, i.e. 5–1000ng/mL. Extraction yields (>85%), precision (RSD < 3.5%) and accuracy (recovery 88–93%) were all within acceptable levels of confidence. After validation, the method was successfully applied to the determination of artemisinin in A. annua extracts. Analyte content was widely variable (up to twenty-fold) according to the starting material and the extraction procedure, ranging between 5.9μg/g and 109μg/mL. The cytotoxic activity of all analysed extracts was also tested on human leukemic cells by viable cell count and cell cycle analysis. Artemisinin concentrations and biological activity were carefully evaluated and the observed antiproliferative effects varied according to artemisinin content in each extract type. This highlights the need to quantitatively analyse the main active constituent of plant extracts and the obtained data have shown to be promising for the choice of the related herbal product dosage
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Intra-specific variation in the little-known Mediterranean plant Ptilostemon casabonae (L.) Greuter analysed through phytochemical and biomolecular markers
No full textPtilostemon casabonae (L.) Greuter is a Mediterranean endemism traditionally used for its health-giving properties. Little is known about this species, therefore this study provides additional information about the phytochemical and biomolecular patterns of this plant, to have a combined fingerprint as a taxonomic tool. Several
P. casabonae specimens were therefore collected from three different sites, two from Sardinia (Italy) and one
from Corsica and the hydroalcoholic extracts of their aerial parts were investigated through HPLC-PDA-MS/MS
analysis to study the phenolic composition. Quercetin, luteolin, kaempferol, apigenin and diosmetin O-glycosides, and caffeoylquinic acid derivatives were found as main components. Samples from the three sites showed
similar phenolic profiles, although statistical analyses highlighted some quantitative differences for several
compounds.
The biomolecular analysis included amplification and sequencing of ITS, 5S-rRNA-NTS and psbA regions. No
difference was found in the nucleotides among the P. casabonae samples from different geographical origins;
however, a comparison with other Ptilostemon species sequences from Genbank, revealed an interspecific
variability of ITS and psbA regions.
The combination of the results of the phytochemical and biomolecular studies provide information on P.
casabonae useful to depict this little-known plant, which can also be applied for future investigations and to
obtain a fingerprint of it. Moreover, the stability of the phenolic profile within the species affords to identify a set
of specialised metabolites useful for its chemotaxonomic characterization. At the same time, the stability of the
biomolecular profile of P. casabonae, and the identification of sequences specific for this species, enables to
identify useful biomolecular markers to distinguish it unequivocally
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
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