1,721,087 research outputs found
Blood microsampling for untargeted lipidomics
No full textLipidomics has become a good bioanalytical tool for biomarker identification in a wide range of diseases. To this aim, whole blood could be promisingly exploited to obtain as much information as possible, despite the well-known intrinsic problems of this biological matrix, mainly related to sampling invasiveness, pre-analytical manipulation and processing, when compared to plasma and serum. To overcome the disadvantages of classic whole blood analysis, two microsampling approaches are proposed: Dried Blood Spot (DBS) and Volumetric Absorptive Microsampling (VAMS). Both techniques allow the collection of small amounts of matrix (20 μL) in a minimally invasive way, directly by fingerprick followed by drying and storage at room temperature. After the loss of water, often responsible for degradation reactions, dried microsamples ensure analyte stability. In addition, VAMS device can absorb a fixed and highly reproducible whole blood volume by means of a hydrophilic polymer tip, regardless of haematocrit value. Fast and feasible original pretreatment procedures have been developed and optimised by testing different pure and mixture solvents and extraction means. To evaluate the best performances for each lipid class and sampling mode, 15 benchmark lipids have been chosen, being representative for the most abundant lipid categories. Quali-quantitative results by means of an originally developed high-resolution UHPLC-MS/MS method were processed and compared by using a multivariate data analysis approach. This allowed to define the best extraction protocol for DBS and VAMS and, after comparison with fluid blood, to suggest VAMS strategy as a promising alternative procedure for blood sampling for untargeted lipidomics
Microfluidic-based blood microsampling platform for the TDM of psychiatric patients under polypharmacy treatment: a patient-centric study
No full textMicrofluidic-based volumetric sampling as a haematocrit-independent DBS collection strategy
No full textCentral nervous system (CNS) drugs require accurate therapeutic drug monitoring (TDM) in a combined bioanalytical and clinical approach. TDM is performed in order to evaluate the suitability of prescribed therapies by measuring drug plasma concentrations to optimise dose regimen, minimise toxicity and for overall clinical decision-making. For this purpose, the use of microsampling, namely dried blood spots (DBS), involves considerable advantages compared to the classic in-tube plasma analysis approach, both for clinicians and patients: in fact, a minimally invasive sample collection allows more frequent and accurate monitoring. These advantages are in addition to those related to simplified handling and storage, fast processing and feasible analysis procedures. On the other hand, quali-quantitative results obtained by the DBS approach can be affected by volumetric bias due to blood haematocrit (HCT) and density, reflecting on spot size and homogeneity, sampling reproducibility, accuracy and precision of analytical data.
For this reason, in-depth studies have been carried out in order to investigate the correlations between HCT values and DBS analysis results. To overcome HCT-dependent bias, an alternative strategy based on microfluidic devices has been proposed: a fixed, small volume (5-10 μL) of whole blood is accurately collected in a microfluidic channel-based device to generate DBS samples regardless of blood viscosity. As a proof of concept, this innovative approach was designed and developed on aripiprazole, an atypical antipsychotic used in the treatment of schizophrenia and bipolar disorder. To this aim, an original analytical methodology was developed, validated and successfully applied for the analysis of DBS samples obtained by microfluidic devices from patients undergoing aripiprazole treatment.
The resulting data has shown the novel microfluidic-based microsampling procedure grants accurate and precise results, irrespective of HCT. This research work provides an effective strategy based on microcapillaries to collect a fixed small volume of whole blood, which could overcome HCT biases in DBS and promises to be feasible and reliable while maintaining all the advantages of classic DBS analysis, making it suitable for widespread bioanalytical applications
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
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