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MXene supported Iron single-atom catalyst for bio sensing applications
No full textThe adrenal medulla is the inner part of adrenal glands located above each kidney, that produces catecholamines. Neuroblastoma and pheochromocytoma are the most prevalent malignancies of the adrenal medulla. Quantitative diagnosis of urinary catecholamines using HPLC-coupled Mass detectors is the current method for the diagnosis of neuroblastoma and pheochromocytoma. There are two major problems with this approach, (i) Because the catecholamines concentrations have short half-life (10-100 s), a series of urine tests must be performed throughout 24hr, detecting each catecholamine separately, is inconvenient and time-consuming; (ii) mass detectors are expensive, bulky, and require highly skilled personal.
Vanillylmandelic (VMA), and homavanillic acid (HVA) are the by-products of catecholamines and are emerging alternative biomarker for catecholamines due to their high stability. Here, we developed a rapid, sensitive, miniaturized, and cheaper sensing platform for simultaneous quantifications of dopamine (DA), VMA, and HVA, with the aid of iron single-atom catalysts (Fe-SACs), based electrochemical sensor. SACs are atomically distributed metal atoms that have a maximum atomic utility rate of nearly 100%, compared to 30% for traditional metal nanoparticles. MXene sheets are employed to stabilize Fe-SACs, where, the exposed lone pairs of MXene serve as sites covalently linking high-energy single Fe atoms. MXene/Fe-SACs were synthesized by treating Ti3C2TxMXene with Iron chloride via freeze-drying followed by annealing. The successful formation of the material was verified by state-of-the-art characterizations. The MXene/Fe-SACs show superior electrocatalytic performance to the commonly used Fe- nanomaterials. Then, it was coated on the electrode surface and used to analyze DA, VMA, and HVA simultaneously via cyclic voltammetry (CV) and square-wave voltammetry (SWV). Under optimized conditions, the MXene/Fe-SACs electrochemical sensor showed detection limits as low as 1 nM and a linear range between 1 nM-100 μM for DA, LOD of 5 nM & linear range of 10 nM-100 μM VMA, and LOD of 10 nM & linear range of 20 nM-100 μM HAV. The method proved successful in detecting biomarkers in (spiked) synthetic urine and human serum. Furthermore, the method was successfully demonstrated in the determination of DA release from PC12 live cells, suggesting the wide practical use of SACs in sensing catecholamines-related metabolites
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Electrochemical Platform for Monitoring Neurotransmitters and Therapeutic Drugs for Neural Diseases
No full textNeurodegenerative diseases (NDs) are a heterogeneous group of disorders characterized by the progressive dysfunction and degeneration of neurons within the central nervous system (CNS). Prominent examples include Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease, and amyotrophic lateral sclerosis (ALS). Among the multiple factors contributing to their onset, ageing is widely recognized as the most significant risk factor. Early detection and precise monitoring of neurotransmitters and neuroactive drugs are therefore essential for understanding disease progression and for improving therapeutic strategies.
In this thesis, a series of electrochemical sensing platforms were developed for monitoring neurotransmitters and neural drugs, focusing on dopamine, L-DOPA, and vancomycin. First, a laser-scribed graphene (LSG) electrode decorated with a metal organic framework (MOF) based material was fabricated for the detection of dopamine using both electrochemical and colorimetric approaches. Building upon this, a multiplexed LSG electrode decorated with single-atom catalysts was developed and successfully applied for sensitive dopamine detection. The platform was then extended to microneedle-based electrodes, where LSG microneedles decorated with dual single-atom catalysts enabled the minimally invasive detection of L-DOPA directly in interstitial fluid (ISF). Finally an aptamer functionalized microneedle array was engineered for the continuous monitoring of vancomycin, a clinically relevant narrow therapeutic index antibiotic. This platform was validated in vivo in a mouse model, demonstrating its potential for real-time therapeutic drug monitoring.
Collectively, these results highlight the versatility of advanced electrochemical biosensing platforms ranging from MOF decorated graphene to single atom catalyst modified microneedles for neurotransmitter and drug monitoring. The technologies developed in this chapter not only offer new opportunities for personalized medicine in neurodegenerative diseases but also provide a foundation for future minimally invasive, real-time sensing strategies in clinical settings
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Get PDFWe 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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