1,720,956 research outputs found
Greenly synthesised biocompatible graphene/zirconia nanocomposite: towards the development of a biosensor for the detection of lung cancer biomarkers
Get PDFEarly detection improves the survival rate of lung cancer. Routine check-up gives rise to early detection, however, conventional screening methods such as X-ray and computed tomography (CT) are incompetent for routine check-up of lung carcinoma due to health hazards associated with repeated exposure to ionizing radiation. These limitations call for a safer, faster, and cheaper solution - the biosensor. In this study, an electrochemical sensor was fabricated using graphene/zirconia (ZG)-modified screen-printed carbon electrode (SPCE). A green approach using solvent exfoliation alongside hydrothermal treatment was employed to prepare the ZG nanocomposites. Material characterisation suggested that pristine graphene and well-hybridised ZG nanocomposite were synthesised. Alongside material characterisation, a cytotoxicity test was performed on the ZG nanocomposite to address the issue of potential hazards during material synthesis and sensor fabrication. The result showed that the ZG nanocomposite had no adverse effects on human lung cells (MRC5) and skin cells (HaCaT), with a half-maximal inhibitory concentration (IC50) value of >500 µg/ml.
Before the development of an immunosensor and genosensor, the potential of the ZG-based platform as an electrochemical sensor for electroanalytical application was demonstrated via acetaminophen detection. The electrochemical sensor exhibited favourable performances for the detection of acetaminophen ranging from 10 μM to 100 μM. A limit of detection (LOD) of 75.5 nM, repeatability of < 3% relative standard deviation (RSD), reproducibility of 5 % RSD, stability of 95% after 5 days of storage alongside decent selectivity to acetaminophen in the presence of interfering species were observed. This finding subsequently motivated the exploration of the platform to serve as a genosensor enhanced with 1-pyrenebutyric-acid-N-hydroxysuccinimideester (PY) biolinker to differentiate wild-type and mutated exon-19 sequences in epidermal growth factor receptor (EGFR). The exon-19 mutation is common among lung cancers. The fabricated genosensor was able to quantify the concentration of wild-type exon-19 in the range of 5 nM to 1 µM, with a linearity coefficient of R2= 0.99 and a LOD of 1.7 nM. The sensor was observed to produce reproducibility of 8.3% of RSD and stability of 90% after 8 days of storage. Most importantly, the sensor was capable of generating distinctive signals for wild-type and mutated exon-19, making it valuable for the detection of genetic mutation. An immunosensor for the detection of carcinoembryonic antigen (CEA) was proposed. CEA is a glycoprotein involved in cell adhesion and is known to be over-expressed in serum of lung cancer patients. Decent performances were exhibited by the immunosensor for CEA detection with a 4.25 pg/ml LOD and a correlation coefficient of R2= 0.99 within a linear working range from 0.01 ng/ml to 10 ng/ml. The immunosensor exhibited high specificity for CEA against interfering species, decent stability for up to 20 days, and reasonable reproducibility of 4.27% RSD. The immunosensor has also presented a good recovery of CEA in human serum, in which the detected CEA level was in close agreement ( < 7% deviation) with the actual concentration.
The key characteristics of the sensors reported in this work offered appealing merits on their own: the stable PY biolinker immobilisation technique, the biocompatible ZG electrode material, the handiness of disposable design and the potential for miniaturisation; hence, hybridizing all these merits produced a promising electrochemical testing platform that subsequently opened up a new avenue for early detection of malignant conditions
Greenly synthesised biocompatible graphene/zirconia nanocomposite: towards the development of a biosensor for the detection of lung cancer biomarkers
Get PDFEarly detection improves the survival rate of lung cancer. Routine check-up gives rise to early detection, however, conventional screening methods such as X-ray and computed tomography (CT) are incompetent for routine check-up of lung carcinoma due to health hazards associated with repeated exposure to ionizing radiation. These limitations call for a safer, faster, and cheaper solution - the biosensor. In this study, an electrochemical sensor was fabricated using graphene/zirconia (ZG)-modified screen-printed carbon electrode (SPCE). A green approach using solvent exfoliation alongside hydrothermal treatment was employed to prepare the ZG nanocomposites. Material characterisation suggested that pristine graphene and well-hybridised ZG nanocomposite were synthesised. Alongside material characterisation, a cytotoxicity test was performed on the ZG nanocomposite to address the issue of potential hazards during material synthesis and sensor fabrication. The result showed that the ZG nanocomposite had no adverse effects on human lung cells (MRC5) and skin cells (HaCaT), with a half-maximal inhibitory concentration (IC50) value of >500 µg/ml.
Before the development of an immunosensor and genosensor, the potential of the ZG-based platform as an electrochemical sensor for electroanalytical application was demonstrated via acetaminophen detection. The electrochemical sensor exhibited favourable performances for the detection of acetaminophen ranging from 10 μM to 100 μM. A limit of detection (LOD) of 75.5 nM, repeatability of < 3% relative standard deviation (RSD), reproducibility of 5 % RSD, stability of 95% after 5 days of storage alongside decent selectivity to acetaminophen in the presence of interfering species were observed. This finding subsequently motivated the exploration of the platform to serve as a genosensor enhanced with 1-pyrenebutyric-acid-N-hydroxysuccinimideester (PY) biolinker to differentiate wild-type and mutated exon-19 sequences in epidermal growth factor receptor (EGFR). The exon-19 mutation is common among lung cancers. The fabricated genosensor was able to quantify the concentration of wild-type exon-19 in the range of 5 nM to 1 µM, with a linearity coefficient of R2= 0.99 and a LOD of 1.7 nM. The sensor was observed to produce reproducibility of 8.3% of RSD and stability of 90% after 8 days of storage. Most importantly, the sensor was capable of generating distinctive signals for wild-type and mutated exon-19, making it valuable for the detection of genetic mutation. An immunosensor for the detection of carcinoembryonic antigen (CEA) was proposed. CEA is a glycoprotein involved in cell adhesion and is known to be over-expressed in serum of lung cancer patients. Decent performances were exhibited by the immunosensor for CEA detection with a 4.25 pg/ml LOD and a correlation coefficient of R2= 0.99 within a linear working range from 0.01 ng/ml to 10 ng/ml. The immunosensor exhibited high specificity for CEA against interfering species, decent stability for up to 20 days, and reasonable reproducibility of 4.27% RSD. The immunosensor has also presented a good recovery of CEA in human serum, in which the detected CEA level was in close agreement ( < 7% deviation) with the actual concentration.
The key characteristics of the sensors reported in this work offered appealing merits on their own: the stable PY biolinker immobilisation technique, the biocompatible ZG electrode material, the handiness of disposable design and the potential for miniaturisation; hence, hybridizing all these merits produced a promising electrochemical testing platform that subsequently opened up a new avenue for early detection of malignant conditions
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
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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