1,720,985 research outputs found
Antimicrobial peptides: the LPS connection
No full textAn expanding body of evidence is rendering manifest that many cationic antimicrobial peptides are
endowed with different properties and activities, well beyond their direct action on microbes. One of
the most interesting and potentially important research avenue on the alternative use of antimicrobial
peptides grounds on their affinity toward lipopolysaccharide (LPS), the endotoxin, responsible for the
systemic inflammatory response syndrome (SIRS) and related, often fatal, disorders that can follow Gramnegative
infections. Indeed, not only do several antimicrobial peptides, such as cathelicidins, display an
ability to strongly bind LPS and break its aggregates, but they have also been demonstrated to suppress
LPS-induced pro-inflammatory responses in vitro and to protect from sepsis in animal models. Although
many aspects still need to be carefully evaluated – some of which are highlighted here – a mix of antimicrobial,
LPS-sequestering/neutralization, and immunomodulatory features make cationic peptides, and
especially synthetic or semi-synthetic amphiphilic compounds built on their scheme, attractive candidates
for novel drugs to be administered in antisepsis therapies. These therapies will probably hinge either on
compounds able to intervene at multiple points in the sepsis cascade or on the combination of two or
more immunomodulators
Difosfani binaftilici P,P'-eterotopici privi di simmetria C2. Sintesi e applicazioni in catalisi asimmetrica
No full textDifosfani atropisomerici a nucleo diarilico come la BINAP attirano sempre interesse a causa della
loro eccezionale abilità nell'indurre asimmetria in reazioni catalizzate da metalli di transizione.1
Grazie alla presenza di centri omotopici al fosforo, questi leganti associano la chiralità assiale alla
simmetria C
2
.
Recentemente abbiamo portato a compimento con successo la sintesi dei primi difosfani a scheletro
binaftilico privi di simmetria C
2
(BINAPP') 3 a partire dal ditriflato del binaftolo enantiopuro 1.2
Questi leganti sono stati preparati con una procedura a più stadi che prevede la sostituzione in
sequenza dei due gruppi triflato.
Il difosfano a simmetria C
1
3 (Ar=o-tolile) ottenuto in questo modo, ha fornito enantioselettività
superiori alla BINAP nell'alchilazione allilica dell'1,3 difenilpropenilacetato catalizzata dal palladio
e nell'idrogenazione di derivati dell'acido acetammidoacrilico catalizzata dal rodio. I complessi
cationici di rodio(I) 4 e 5 sono stati preparati per l'uso come catalizzatori nell'idrogenazione
asimmetrica. Entrambi mostrano all'NMR proprietà dinamiche che sono state attribuite alla
rotazione impedita dei gruppi o-tolilici
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
Lipopeptides as anti-infectives: a practical perspective
No full textLipopeptide antibiotics represent an old class of antibiotics that were discovered over 50 years ago, which includes the old polymyxins but also new entries, such as the recently approved daptomycin. They generally consist of a hydrophilic cyclic peptide portion attached to a fatty acid chain which facilitates insertion into the lipid bilayer of bacterial membranes. This review presents an overview of this class of antibiotics, focusing on their therapeutic applications and putting particular emphasis on chemical modifications introduced to improve their activit
Application of DNA microarray technology in Bos taurus genomic analysis: preliminary results
No full textVariations 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
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