1,720,955 research outputs found
Silica Coated Core-Shell Quantum Dot-based Electro-Immunosensor for Interferon Gamma TB Disease Biomarker
No full text>Magister Scientiae - MScTuberculosis (TB) is a disease that results from infection by Mycobacterium tuberculosis, which is regarded the most common infecting organism. TB has killed countless numbers of people particularly in underdeveloped countries. TB bacteria can remain inactive or in dormant state for years without causing symptoms or spreading to other subjects, but as soon as the immune system of the host becomes weakened, the bacteria become active and infect mainly the lungs along with other parts of body. TB cases are further aggravated by other illnesses that affect the immune system, such as human immune virus (HIV), which is very prevalent in resource-poor countries. Interferon-gamma (IFN-γ) is a TB biomarker that has found to have all the qualities that are needed to help and cure Tuberculosis disease. Early diagnosis and treatment are essential measures for effectively controlling the disease. Traditional microbial culture-based tests are the most common methodologies currently used. Usually, these methods involve cell culture, cell counts, and cell enrichment, but this process is time-consuming and laborious, especially for the slow-growing bacteria like M. tuberculosis. Sputum smear is one of the methods currently used to detect acid fast bacilli (AFB) in clinical specimens or fluorescent staining. It is a cost-effective tool for diagnosing patients with TB and to monitor the progress of treatment especially in developing countries. The traditional method of inoculating solid medium such as Lowerstein-Jensen (L-J) or 7H10/7H11 media is also used currently it is slow and takes 6-8 weeks of incubation to diagnose the infection and further more time to determine the susceptibility patterns. The microscopic observation drug susceptibility (MODS) assay they are also used currently they rely on light microscopy to visualize the characteristic cording morphology of M. tuberculosis in liquid culture. MODS has shorter time to culture positivity (average 8 days) compared with LJ medium (average ~26 days), they are very expensive. The Gen-Probe assay specific for M. tuberculosis complex is a rapid detection that is also used, nucleic acid amplification (NAA) test results can be obtained as fast as in two hours (provided if a positive culture is present); it also has a high sensitivity of 99% and specificity of 99.2%. It holds the disadvantage of needing of positive culture that can take several days. Enzyme-linked immunosorbent assay (ELISA), is a test that uses antibodies and colour change to identify a substance. ELISA is an assay that uses a solid-phase enzyme immunoassay (EIA) to detect the presence of a substance, usually an antigen, in a liquid sample or wet sample. It can be used to detection of Mycobacterium antibodies in tuberculosis. The Amplified Mycobacterium Tuberculosis Direct Test (AMTDT) is used for the detection of M. tuberculosis it enables the amplification and detection of M. tuberculosis rRNA directly from respiratory specimens. The diagnostic methods employing genetechnology based on the amplification of DNA or RNA are expected to improve the speed, sensitivity, and specificity of Mycobacterium tuberculosis detection. TB rapid cultivation detection technique, such as MB/BacT system, BactecMGIT 960 system and flow cytometry. The BACTEC MGIT960 system (Becton Dickinson, Sparks, MD) performs incubation and reading of the tubes continuously inside the machine using a predefined algorithm to interpret the fluorescent signal and giving the results as positive or negative. When performing DST, the BACTEC MGIT960 interprets the results as susceptible or resistant to the antibiotic under study. Results are available within 8 days. A recent meta-analysis of the published studies found high accuracy and high predictive values associated with the use of BACTEC MGIT960. These methods are more sensitive and rapid than the traditional microbial culture-based methods. However, they cannot provide the detection results in real-time and most of these methods are centralized in large stationary laboratories because complex instrumentation and highly qualified technical staff are required. Recently, Food and Drug Administration (FDA) approved two new assays that were introduced. These two assays detect in vitro a specific immune response to M. tuberculosis. These tests are the QuantiFERON-TB Gold In-Tube (Cellestis/Qiagen, Carnegie, Australia) and the T-SPOT.TB assay (Oxford Immunotec, Abingdon, United Kingdom). Both assays use whole blood from the patient and measure the production of interferon gamma after the whole blood is exposed to specific antigens from M. tuberculosis. These tests are based on the knowledge that IFN-γ is a product of an active cell-mediated immune response induced by M. tuberculosis. However, TB detection remains a major obstacle due to several drawbacks of these methods. To date, the number of diagnosis approaches for TB has increased as the disease continues to be a major public health problem worldwide and most conventional detection technologies present difficulties in recognizing the presence of M. tuberculosis, since they are time consuming, do not provide clinically reliable results and significantly lack of sensitivity.
This thesis focusedon developing two binary and one ternary-electrochemically quantum dots, all synthesised at room temperature in aqueous media for detecting (IFN-γ). Copper telluride (CuTe) and Zinc telluride (ZnTe) was prepared to check how does the two quantum dot behave individual and also to check on how they behave when they are combined and formed ternary quantum dots (CuZnTe). The electrochemical studies of the binary CuTe quantum dots, ZnTe quantum dots and the ternary CuZnTe core-shell quantum dots reveal that ternary quantum dots were stable and showed a significant enhancement in the conductivity of CuZnTe core-shell solution compared to that of CuTe and ZnTe, all studied in solution. The three different quantum dots were capped with three different capping reagents which are tetraethyl orthosilicate (TEOS), thioglycolic acid (TGA), (3-mercaptopropyl) trimethoxysilane (MPS). In the study, a label-free electrochemical immunosensor for the detection of interferon gamma (IFN-γ) was prepared for the first time using ternary quantum dots. The biosensor consists of water-soluble silica coated Copper Zinc telluride (CuZnTe core-shell) quantum dots conjugated to a gold electrode. The antibody-antigen were then conjugated on the CuZnTe core-shell QD modified gold electrode. Results from synthesis of two different binary quantum dots are also presented in the study and compared to the results of the CuZnTe core-shell QDs. The CuTe quantum dots had a small average size which was confirmed through HRTEM, SAXS and XRD analysi
Silica Coated Core-Shell Quantum Dot-based Electro-Immunosensor for Interferon Gamma TB Disease Biomarker
Full text link>Magister Scientiae - MScTuberculosis (TB) is a disease that results from infection by Mycobacterium tuberculosis, which is regarded the most common infecting organism. TB has killed countless numbers of people particularly in underdeveloped countries. TB bacteria can remain inactive or in dormant state for years without causing symptoms or spreading to other subjects, but as soon as the immune system of the host becomes weakened, the bacteria become active and infect mainly the lungs along with other parts of body. TB cases are further aggravated by other illnesses that affect the immune system, such as human immune virus (HIV), which is very prevalent in resource-poor countries. Interferon-gamma (IFN-γ) is a TB biomarker that has found to have all the qualities that are needed to help and cure Tuberculosis disease. Early diagnosis and treatment are essential measures for effectively controlling the disease. Traditional microbial culture-based tests are the most common methodologies currently used. Usually, these methods involve cell culture, cell counts, and cell enrichment, but this process is time-consuming and laborious, especially for the slow-growing bacteria like M. tuberculosis. Sputum smear is one of the methods currently used to detect acid fast bacilli (AFB) in clinical specimens or fluorescent staining. It is a cost-effective tool for diagnosing patients with TB and to monitor the progress of treatment especially in developing countries. The traditional method of inoculating solid medium such as Lowerstein-Jensen (L-J) or 7H10/7H11 media is also used currently it is slow and takes 6-8 weeks of incubation to diagnose the infection and further more time to determine the susceptibility patterns. The microscopic observation drug susceptibility (MODS) assay they are also used currently they rely on light microscopy to visualize the characteristic cording morphology of M. tuberculosis in liquid culture. MODS has shorter time to culture positivity (average 8 days) compared with LJ medium (average ~26 days), they are very expensive. The Gen-Probe assay specific for M. tuberculosis complex is a rapid detection that is also used, nucleic acid amplification (NAA) test results can be obtained as fast as in two hours (provided if a positive culture is present); it also has a high sensitivity of 99% and specificity of 99.2%. It holds the disadvantage of needing of positive culture that can take several days. Enzyme-linked immunosorbent assay (ELISA), is a test that uses antibodies and colour change to identify a substance. ELISA is an assay that uses a solid-phase enzyme immunoassay (EIA) to detect the presence of a substance, usually an antigen, in a liquid sample or wet sample. It can be used to detection of Mycobacterium antibodies in tuberculosis. The Amplified Mycobacterium Tuberculosis Direct Test (AMTDT) is used for the detection of M. tuberculosis it enables the amplification and detection of M. tuberculosis rRNA directly from respiratory specimens. The diagnostic methods employing genetechnology based on the amplification of DNA or RNA are expected to improve the speed, sensitivity, and specificity of Mycobacterium tuberculosis detection. TB rapid cultivation detection technique, such as MB/BacT system, BactecMGIT 960 system and flow cytometry. The BACTEC MGIT960 system (Becton Dickinson, Sparks, MD) performs incubation and reading of the tubes continuously inside the machine using a predefined algorithm to interpret the fluorescent signal and giving the results as positive or negative. When performing DST, the BACTEC MGIT960 interprets the results as susceptible or resistant to the antibiotic under study. Results are available within 8 days. A recent meta-analysis of the published studies found high accuracy and high predictive values associated with the use of BACTEC MGIT960. These methods are more sensitive and rapid than the traditional microbial culture-based methods. However, they cannot provide the detection results in real-time and most of these methods are centralized in large stationary laboratories because complex instrumentation and highly qualified technical staff are required. Recently, Food and Drug Administration (FDA) approved two new assays that were introduced. These two assays detect in vitro a specific immune response to M. tuberculosis. These tests are the QuantiFERON-TB Gold In-Tube (Cellestis/Qiagen, Carnegie, Australia) and the T-SPOT.TB assay (Oxford Immunotec, Abingdon, United Kingdom). Both assays use whole blood from the patient and measure the production of interferon gamma after the whole blood is exposed to specific antigens from M. tuberculosis. These tests are based on the knowledge that IFN-γ is a product of an active cell-mediated immune response induced by M. tuberculosis. However, TB detection remains a major obstacle due to several drawbacks of these methods. To date, the number of diagnosis approaches for TB has increased as the disease continues to be a major public health problem worldwide and most conventional detection technologies present difficulties in recognizing the presence of M. tuberculosis, since they are time consuming, do not provide clinically reliable results and significantly lack of sensitivity.
This thesis focusedon developing two binary and one ternary-electrochemically quantum dots, all synthesised at room temperature in aqueous media for detecting (IFN-γ). Copper telluride (CuTe) and Zinc telluride (ZnTe) was prepared to check how does the two quantum dot behave individual and also to check on how they behave when they are combined and formed ternary quantum dots (CuZnTe). The electrochemical studies of the binary CuTe quantum dots, ZnTe quantum dots and the ternary CuZnTe core-shell quantum dots reveal that ternary quantum dots were stable and showed a significant enhancement in the conductivity of CuZnTe core-shell solution compared to that of CuTe and ZnTe, all studied in solution. The three different quantum dots were capped with three different capping reagents which are tetraethyl orthosilicate (TEOS), thioglycolic acid (TGA), (3-mercaptopropyl) trimethoxysilane (MPS). In the study, a label-free electrochemical immunosensor for the detection of interferon gamma (IFN-γ) was prepared for the first time using ternary quantum dots. The biosensor consists of water-soluble silica coated Copper Zinc telluride (CuZnTe core-shell) quantum dots conjugated to a gold electrode. The antibody-antigen were then conjugated on the CuZnTe core-shell QD modified gold electrode. Results from synthesis of two different binary quantum dots are also presented in the study and compared to the results of the CuZnTe core-shell QDs. The CuTe quantum dots had a small average size which was confirmed through HRTEM, SAXS and XRD analysi
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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