1,721,008 research outputs found
Electronic detection of neurological signalling agents
Full text linkThis project will advance knowledge within the realm of neurological signalling agents/neu-rotransmitters and other biomarkers of disease. Electrochemistry is a valuable interrogation tool for quantitative analysis of such redox species.
One main goal is to overcome problems inherent to the simultaneous detection of neuro-transmitters, such as overlapping redox potentials and electrode fouling due to build-up of surface oxidation products. The use of electrodeposited catalysts enables selective detection in multicom-ponent systems at the required physiological levels. The carbon-based nanoparticles used in this work showed good potential when it comes to solve these problems.
Another goal is to explore the viability of a smartphone-operated potentiostat system in the electrochemical detection of neurotransmitters. Phone systems have been used in electrochemical formats for electroactive substances detection, but, to our knowledge, have not been employed as AC signal generators for amperometric sensor signal acquisition. The system appeared to work correctly. However, it needs additional tests and hardware and software development. It seems to be a good option to facilitate the electrochemical detection process, being low-cost, fast and port-able.
Finally, another goal is to explore the electrochemical properties of galectin-3, protein that has been considered regarding investigations of concussion and cancer biomarkers. Some en-zyme-linked immunosorbent assays for its optical detection already exist. As far as we know, electrochemistry is a novel approach for the detection of galectin-3 in biological fluids. The re-sults showed correlation between the optical and electrochemical data, which is a good indicator of the success of the electrochemical approach. The positive results obtained with each approach validate the work, which is a good summary of areas that can be improved when it comes to the usage of electrochemistry in diagnostic
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
Development of Novel Pt(IV)-Carbohydrate Derivatives as Targeted Anticancer Agents against Osteosarcoma
Full text linkDespite the enormous importance of cisplatin as a chemotherapeutic agent, its application is impacted by dose-limiting side effects and lack of selectivity for cancer cells. Researchers can overcome these issues by taking advantage of the pro-drug nature of the platinum(IV) oxidation state, and by modifying the coordination sphere of the metal centre with specific vectors whose receptors are overexpressed in tumour cell membranes (e.g., carbohydrates). In this paper we report the synthesis of four novel carbohydrate-modified Pt(IV) pro-drugs, based on the cisplatin scaffold, and their biological activity against osteosarcoma (OS), a malignant tumour which is most common in adolescents and young adults. The carbohydrate-targeting vectors and Pt scaffold are linked using copper-catalysed azide–alkyne cycloaddition (CuAAC) chemistry, which is synonymous with mild and robust reaction conditions. The novel complexes are characterised using multinuclear 1D-2D NMR (1H, 13C and 195Pt), IR, HR-MS, Elem. Analyses, and CV. Cytotoxicity on 2D and 3D and cell morphology studies on OS cell lines, as well as non-cancerous human foetal osteoblasts (hFOBs), 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
Design and development of some amperometric biosensors based on enzymes, antibodies and plant tissue
Full text linkAmperometric biosensors for various drugs and metabolites have been developed, based on immobilised enzymes in both aqueous and organic media. Chapter 1 serves as a general review of the field of biosensors, including both an overview of recognition methods together with the techniques involved in transduction. The remainder of the thesis is divided into four experimental chapters. The first of these describes the development of some amperometric enzyme electrodes for certain drugs and metabolites in aqueous solution. Various immobilisation methods, including use of polymers such as Nafion and Eastman AQ55D, gelatine membranes, entrapment of the enzyme within electropolymerised films, together with direct adsorption, have been employed. Discriminative permselective films were found to show great effectiveness in excluding interfering compounds commonly found in serum. Application to the clinical and in vivo fields are discussed. Limits of detection down to the jiM level were found. Fast wash times permitted application to flowing streams with frequencies of up to 200 samples per hour, with good precision. The second experimental chapter deals with the construction of biosensors for inhibiting compounds in the organic phase. A study of the kinetics of tyrosinase at the rotating disc electrode in non-aqueous media is also described. Reactions which are impossible in aqueous media due to kinetic or thermodynamic constraints become possible in non-aqueous solvents. The recent discovery that biocatalysts can function in extreme environments such as organic solvents has important implications for the implementation of biosensor technology in formerly inaccessible environments. It also extends the number of detectable analytes to include poorly water soluble organic species in the petrochemical, food and environmental areas. Chapter 4 deals with the electrochemistry of the anticancer drug 7-OH-coumarin and the development of an immunosensor for this compound. The final experimental chapter deals with the detection of some metal ions using a plant tissue modified carbon paste electrode, and includes speciation studies of copper
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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