1,720,960 research outputs found
La biologia computazionale a servizio del linfoma canino: nuovi orizzonti?
No full textScopo del lavoro - Il linfoma è uno dei tumori più frequenti nel cane, rappresentando circa il 7-24% di tutte le neoplasie e oltre l’80% delle neoplasie ematologiche. Origina dal tessuto linfoide (linfonodi, milza, midollo) e può estendersi a tutti gli organi e tessuti dell’organismo ed in genere colpisce cani di mezza età o di età avanzata. Attualmente sono descritti almeno cinque diver- si tipi più frequenti di linfoma canino (LC): multicentrico, mediastinico, gastrointestinale, extra-nodale e del sistema nervoso centrale1. La sua eziologia non è nota ed è ritenuta essere una patologia multifattoriale. In particolare sono state riscontrate aber- razioni cromosomiche, il coinvolgimento di retrovirus e cause ambientali (erbicidi, solventi, inquinamento industriale). La pato- genesi rimane in gran parte ignota2.
In questo contesto, abbiamo utilizzato innovative metodiche di biomedical text mining (o Biomedical Informatics Natural Lan- guage Processing, BioNLP) e di modellistica computazionale per identificare le proteine coinvolte nel LC, sia per chiarirne i meccanismi patogenetici che, potenzialmente, per proporre possibili targets terapeutici e/o markers diagnostici. In particolare:
1) mediante l’uso del BioNLP è stata ottenuta una lista di proteine coinvolte nell’eziopatogenesi del LC accedendo alle
conoscenze contenute nel testo nascosto e non strutturato (hidden and unstructured text) presente negli articoli indiciz- zati su PubMed (http://www.ncbi.nlm.nih.gov/pubmed)3. In tal modo è stato possibile implementare le conoscenze ad oggi disponibili;
2) è stato costruito un modello computazionale basato sulla teoria delle reti biologiche (biological networks) con le molecole coinvolte (nodi della rete) e le loro interazioni (links tra i nodi)3;
3) l’analisi della topologia della rete ha consentito di identificare le molecole caratterizzate da un più elevato grado di control- lo sulla rete stessa, ovvero quelle che verosimilmente possono essere ottimi candidati come markers diagnostici e/o target terapeutici4,5.
Materiali e metodi - Per il BioNLP è stato usato il software Agilent Literature Search 3.1.1 (LitSearch version 2.6.9). L’ac- cesso ai dati è stato realizzato tra il 2 ed il 4 febbraio 2015. Una volta ottenuta la lista di proteine coinvolte, è stata condotta un’analisi per definirne le interazioni mediante il software STRING (Search Tool for the Retrieval of Interacting Genes/Proteins, http://string-db.org/). La rete formata dalle proteine (nodi) e dalle loro interazioni (links) è stata realizzata e visualizzata mediante Cytoscape 3.2.1, la topologia è stata analizzata con plug-in Network Analyzer (http://med.bioinf. mpi-inf. mpg.de/netanalyzer/index.php)6,7.
Risultati - La ricerca mediante BioNLP ha consentito di identificare una lista di 79 proteine coinvolte nell’eziopatogenesi del linfoma canino. L’analisi su STRING ha permesso di definire le loro interazioni per creare, con Cytoscape, una rete composta da 31 connected components, 554 nodi e 1614 links. L’analisi della rete (trattata come non diretta) ha permesso di classificarla come rete ad invarianza di scala (node degree distribution: y=370.18 x-1.629, r=0.663, R2=0.762) di tipo gerarchico (clustering coefficient =0.621, Averaged Clustering Coefficent vs. Number of Neighbors: y=1.932 x-0.629, r=0.915, R2=0.908). Proprio grazie a tale topologia è stato possibile identificare i nodi col maggior numero di links, gli hubs del sistema, che dimostrano anche un elevato grado di centralità nella rete (node degree vs. betweenness centrality r=0.676 e vs. closeness centrality r=0.677). Tali proteine sono elencate, in ordine decrescente di controllo, qui di seguito:
c-jun: insieme a c-fos coinvolto nel controllo del ciclo cellulare e nella regolazione dell’apoptosi.
p53: un fattore di trascrizione che regola il ciclo cellulare e ricopre la funzione di soppressore tumorale.
Grb2: un adaptor protein coinvolto nella trasduzione del segnale e nella comunicazione fra cellule; in particolare lega il recet- tore per EGF.
PIK3CB: fosfoinositide 3-chinasi, subunità catalitica beta, coinvolta in varie vie di trasduzione del segnale che regolano la cre- scita cellulare in risposta a vari stimoli mitotici.
LYN: appartiene alla famiglia delle proteinchinasi Src ed espresso principalmente da cellule ematopoietiche, tessuto nervoso, fegato e tessuto adiposo; in particolare nelle cellule emopoietiche è uno degli enzimi chiave coinvolti nella regolazione dell’at- tivazione cellulare.
PIK3R1: fosfatidilinositolo-3-chinasi, ha un importante ruolo nell’azione dell’insulina.
AKT1: attivata dalla fosfatidilinositolo-3-chinasi, i ratti KO per il gene Akt1 sono resistenti ai tumori.
PTPN6: coinvolta nella differenziazione cellulare, ciclo mitotico e trasformazione oncogena.
c-fos: vedi c-jun.
Conclusioni - Grazie all’uso di sofisticate metodiche computazionali è possibile individuare nuove proteine coinvolte nell’e- ziopatogenesi del LC, che potrebbero rappresentare futuri markers diagnostici e/o targets terapeutici
Scientometric study of the effects of exposure to Non-Ionizing Electromagnetic Fields on fertility: a contribution to understanding the reasons of partial failure.
No full texthe exposure to Non-Ionizing-Electromagnetic Fields (NI-EMFs) is often indicated as a cofactor responsible for the fertility reduction, which has been described in recent years. Despite the great interest in this topic and the research effort in exploring it, to date, there are no reliable data. Therefore, we carried out a scientometric analysis of the scientific literature published in peer reviewed Journals concerning this topic to better understand the reasons of this partial failure. To this aim, we identified and analysed 104 papers, published in last 26 years in peer-reviewed Journals, present in ISI Web of Knowledge Core Collection. Then, we analysed the impact of the Journals in which the papers were published as well as that of the single papers, the paper citation dynamics, the keywords citation busts, the geographical localization of citations and the co-authorship dynamics of the Authors. As a result, we found that different animal models (rodent, rabbit, guinea pig, and swine) and different experimental approaches (epidemiological vs. experimental studies) have the same impact, highlighting the lack of universally adopted standard in research activity. The analysis of the temporal trend in keywords and the high differences in citations between the different countries (also in those belonging to the same geographical and socio-economical area) pointed out the difficulties in approaching this branch of study. Lastly, it was evident that the Authors did not behave as a connected community, but as unconnected clusters of very small size. In conclusion, based on the results of our analysis, we think that important efforts must be undertaken to adopt more standardized models and to improve the research quality and the information exchange within the scientific community, with the aim of improving the reliability and usefulness of the results of research regarding the effect of NI-EMFs on fertility
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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