1,721,009 research outputs found
PFAS sensing: Concept design of electrochemical and optical, bio- and biomimetic strategies
Full text linkPFAS sensing project deals with the design of proof-of-concept sensing platforms for the simultaneous determination of per- and polyfluoroalkyl substances (PFAS) in water matrices. By testing electrochemical and optical sensing platforms based on protein receptors or synthetic molecular recognition layers, we explored the limits and potential of PFAS sensing in terms of sensitivity, inter- and intra-class selectivity and real sample applicability, getting familiar with sensing platform design.PFAS sensing project deals with the design of proof-of-concept sensing platforms for the simultaneous determination of per- and polyfluoroalkyl substances (PFAS) in water matrices. By testing electrochemical and optical sensing platforms based on protein receptors or synthetic molecular recognition layers, we explored the limits and potential of PFAS sensing in terms of sensitivity, inter- and intra-class selectivity and real sample applicability, getting familiar with sensing platform design
How to optimize the analytical performance of differential pulse voltammetry: one variable at time versus Design of Experiments
No full textDifferential pulse voltammetry has often been considered one of the most suitable techniques for electroanalytical applications. However, the voltammetric parameters used are often chosen without a proper examination of their effect on the resulting response. In this lab experiment, the students are guided to a more informed choice of the electrochemical parameters to apply depending on the application sought. In the first part of the experiment, we highlight how each voltammetric parameter affects the signal-to-noise ratio and the resolution of the voltammetric response of hydroquinone, taken as an example of the application of this electrochemical technique. A Design of Experiment is then applied to optimize the intensity and the sharpness of the oxidation peak response. Finally, an analogous approach is followed to optimize the peak resolution of an equimolar hydroquinone and catechol mixture to achieve the best separation among the peak current response for the two electrochemical processes. Thanks to these two experiments, the student will identify the correct choice of parameters to optimize as key factors for achieving the best analytical performance in specific applications
Molecular analysis and therapeutic applications of human serum albumin-fatty acid interactions
No full textHuman serum albumin (hSA) is the major carrier protein for fatty acids (FAs) in plasma. Its ability to bind multiple FA moieties with moderate to high affinity has inspired the use of FA conjugation as a safe and natural platform to generate long-lasting therapeutics with enhanced pharmacokinetic properties and superior efficacy. In this frame, the choice of the FA is crucial and a comprehensive elucidation of the molecular interactions of FAs with hSA cannot be left out of consideration. To this intent, we report here a comparative analysis of the binding mode of different FA moieties with hSA. The choice among different albumin-binding FAs and how this influence the pharmacokinetics properties of a broad spectrum of therapeutic molecules will be discussed including a critical description of some clinically relevant FA conjugated therapeutics.LPP
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
An Impedimetric Biosensing Strategy Based on Bicyclic Peptides as Bioreceptors for Monitoring huPA Cancer Biomarker
Full text linkIn the era of liquid biopsies, the reliable and cost-effective detection and screening of cancer biomarkers has become of fundamental importance, thus paving the way for the advancement of research in the field of point-of-care testing and the development of new methodologies and technologies. Indeed, the latter ones can help designing advanced diagnostic tools that can offer portability, ease of use with affordable production and operating costs. In this respect, impedance-based biosensing platforms might represent an attractive alternative. In this work, we describe a proof-of-concept study aimed at designing portable impedimetric biosensors for the monitoring of human urokinase-type plasminogen activator (h-uPA) cancer biomarker by employing small synthetic receptors. Aberrant levels of h-uPA were correlated with different types of cancers. Herein, we report the use of two bicyclic peptides (P2 and P3) which have been engineered to bind h-uPA with high affinity and exquisite specificity. The synthetic receptors were immobilized via biotin-streptavidin chemistry on the surface of commercial screen-printed electrodes. The impedimetric changes in the electrode/solution interface upon incubation of spiked h-uPA samples in the presence of a redox probe were followed via electrochemical impedance spectroscopy. The P3-based impedimetric assay showed the best outcomes in terms of dynamic range and linearity (0.01–1 μg mL−1) and sensitivity (LOD = 9 ng mL−1). To fully assess the performances of P3 over P2, and to compare the label-free architecture vs. labelled architecture, a voltammetric assay was also developed
Mapping the gaps in chemical analysis for the characterisation of aptamer-target interactions
Full text linkAptamers are promising biorecognition elements with a wide applicability from therapeutics to biosensing. However, to successfully use these biomolecules, a complete characterisation of their binding performance in the presence of the target is crucial. Several multi-analytical approaches have been reported including techniques to describe kinetic and thermodynamic aspects of the aptamer-target interaction, and techniques which allow an in-depth understanding of the aptamer-target structures. Recent literature shows the need of a critical data interpretation, a combination of characterisation techniques and suggests the key role of the characterisation protocol design. Indeed, the final application of the aptamer should be considered before choosing the characterisation method. All the limitations and capabilities of the analytical tools in use for aptamer characterisation should be taken into account. Here, we present a critical overview of the current methods and multi-analytical approaches to study aptamer-target binding, aiming to provide researchers with guidelines for the design of characterisation protocols
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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