A comprehensive model, previously developed for a rectangular parallelepiped shaped 0.3 MWt circulating fluidized bed combustor (CFBC) fired with high calorific value coal burning in sand and validated against experimental data is adapted to cylindrical configuration and is extended to incorporate NOx formation and reduction reactions and pressure drops around cyclone, downcomer and loop seal. Its predictive accuracy is tested by applying it to the simulation of Middle East Technical University (METU) 150 kWt CFBC burning low calorific value indigenous lignite with high Volatile Matter/Fixed Carbon (VM/FC) ratio in its own ash and comparing its predictions with measurements. Favorable comparisons are obtained between the predicted and measured temperatures, pressure profiles and emissions of gaseous species. Results reveal that predictive accuracy in pressure profile strongly depends on the correlation utilized for entrainment in dilute zone and that accuracy in NO emission requires data on partitioning of coal nitrogen into char-N and volatile-N and is affected significantly by dilute zone oxygen content.

Circulating tumor cells (CTCs) are known to escape from the primary tumor site and may settle down at the distant organ to grow a second tumor. CTCs are one of causes initiating carcinoma metastasis. Detection of CTCs has been considered to be valuable for cancer management, including diagnosis, prognosis, and clinical treatment management. However, efficient isolation, enumeration, characterization, and genetic analysis of CTCs in whole-blood samples from cancer patients are very challenging due to their extremely low concentration and rare nature (per CTC in blood cells is 1:106–109). With the increasing worldwide death rate associated with cancer, there is a desperate demand for a high-sensitivity, high-throughput, and low-cost detection and separation system. My doctoral research focused on the design and fabrications of the screening system for the detection of CTCs with further analysis of captured CTCs, such as immunofluoresce staining and fluorescence in-situ hybridization (FISH). The distinct significance of this research is that the development of the computer-controlled rotational holder with a series of six inverted microfluidic chips reduced the cost by significantly reducing the consumption of magnetic carriers (25% of the consumed amount used in the commercial CellSearch® system), increasing the capture efficiency by manipulating the blood sedimentation in the microchannel, enhancing the system stability by integrating the micromagnets on the plain glass slide substrate, and achieving high throughput because of the high flow rate (2.5 mL/hr) and large screening volume (screening up to six chips in parallel with each containing 2.5 mL of blood). Immunofluorescence staining and the FISH method have been performed to prove the capability of the system. In addition, the system has been successfully applied for patient samples screening. The incorporation of micromagnets has demonstrated that micromagnets provide localized magnetic forces to scatter the target cancer cells and free nanoparticles throughout the whole channel substrate to increase the channel space usage by 13%. Four cancer cell lines, including COLO 205 (colorectal cancer), SK-BR-3 (breast cancer), MCF-7 (breast cancer), and PC3 (prostate cancer), were spiked in blood samples from healthy donors to verify high capture efficiency of the developed system. On average, over a 97% capture rate was demonstrated for all cell lines. Moreover, the developed screening system has been successfully screened over 40 patient samples, including metastatic lung cancer, breast cancer, prostate cancer, and colorectal cancer. After capture of CTCs, immunofluorescence staining was used to identified the captured cancer cells and the FISH method was performed to characterize the isolated cancer cells by studying the gene expression of CTCs from breast cancer. The proposed automated immunomagnetic microchip-based screening system shows high capture efficiency (average 97% for three spiked cell lines), high throughput (15 mL of blood sample per screening), high sensitivity, high specificity, and low nanoparticle consumption (75% less than CellSearch® system). The screening system provides great promise as a clinical tool for early cancer diagnosis, diagnosis, personalized therapy, and treatment monitoring. / text

Solid cancers often shed (sub)cellular materials into the circulation, such as circulating tumor cells and extracellular microvesicles. Mounting evidence supports that these circulating materials could serve as surrogate cancer markers for classifying primary tumors, stratifying patients for targeted therapies, assessing treatment efficacy, and achieving clinical benefits. A sensor platform capable of sensitive and portable detection of circulating cancer markers would thus be an invaluable tool, that will advance our understanding of tumor biology as well as clinical outcomes. This dissertation describes various systems that we have developed for quantitative analyses of circulating cancer biomarkers. Firstly, we have developed a novel magnetic resonance sensing platform for microvesicle analyses. By using a chip-based platform that combines microfiltration and bioorthogonal nanoparticle targeting, we demonstrate for the first time that magnetic biosensing can be applied for clinical evaluation of circulating microvesicles in blood samples to monitor cancer therapy. Secondly, we have advanced a new plasmonic sensor to achieve label-free detection of microvesicles. Based on periodic nanohole arrays, this platform has been applied for high-throughput protein profiling of microvesicles in native ascites. Finally, we have implemented microfluidic devices to effectively enrich circulating tumor cells from peripheral whole blood, and to enable comprehensive molecular analyses of isolated tumor cells at a single cell resolution. By enabling rapid, sensitive and cost-effective detection of circulating cancer markers, these developed platforms could significantly expand the reach of preclinical and clinical cancer research, in informing therapy selection, rationally directing trials, and improving sequential monitoring to achieve better clinical outcomes.

Molecular analysis of free circulating (fc)DNA has the potential to change the face of medicine, specifically in cancer diagnostics and in monitoring the efficacy of cancer treatments. In this study, a microfluidic device using AC electrokinetics is developed for rapid concentration and detection of fcDNA from blood. The device concentrates fcDNA using a combination of AC electrothermal flow and dielectrophoresis. The electrothermal fluid motion drives fcDNA towards the center of the electrode where dielectrophoretic trapping occurs. Once fcDNA is collected at the center, the concentration in the sample can be determined by fluorescent analysis using an intercalating dye binding to the double-stranded DNA. Effects of operating parameters are investigated to optimize the device's design. The electrokinetic device isolates high molecular weight DNA and can distinguish from low molecular weight DNA. Quantitative detection of fcDNA in physiologically relevant concentrations is demonstrated toward rapid diagnostics of cancer and monitoring of treatment efficacy.

Circulating DNA is fragments of DNA which can be found in the blood of healthy as well as diseased individuals. Higher levels of these nucleic acid molecules can be found in diseased and pregnant individuals in contrast to healthy controls. The origin of circulating DNA has not been elucidated, but release of DNA after apoptosis or necrosis or active release by living cells has been hypothesized. It was concluded in this study that apoptosis or necrosis may only be a minor source of circulating DNA and that release of DNA by living cells might play a major role in the origin, while disturbance of the equilibrium between release by living cells and clearance mechanisms may cause the rise in the levels of circulating DNA observed in different conditions. Before circulating DNA can be analyzed, it has to be isolated from the blood. A number of different preanalytical conditions can have an impact on the quantity and quality of circulating DNA that can be isolated. Furthermore, the choice of isolation and quantification method may also influence the results obtained. Quantitative analysis of circulating DNA was done by real-time PCR analysis of the &Globin gene and the DNA levels obtained for healthy controls and cancer patients correlated with levels reported in the literature. Characterization of total circulating DNA may be beneficial in diagnosis and prognosis and may also contribute to determining the source and function of circulating DNA. In order for characterization to take place a method to clone total circulating DNA was developed and standardized and thirty-five clones were obtained and analyzed. It was found that the sequences contain a large amount of Alu repeats and the significance of this has not been determined yet. This is a first step towards future studies. / Thesis (M.Sc. (Biochemistry))--North-West University, Potchefstroom Campus, 2007

The diagnostic value of extracellular occurring DNA (eoDNA) is limited by our lack of understanding its biological function. eoDNA exists in a number of forms, namely vesicle bound DNA, histone/DNA complexes or nucleosomes and virtosomes. These forms of DNA can also be categorized under the terms circulating DNA, cell free DNA, free DNA and extracellular DNA. The DNA can be released by means of form–specific mechanisms and seem to be governed by cell cycle phases and apoptosis. Active release is supported by evidence of energy dependant release mechanisms and various immunological– and messenger functions. Sequencing has shown that eoDNA sequences present in the nucleome reflects traits and distribution of genome sequences and are regulated by ways of release and/or clearance. eoDNA enables the horizontal transfer of gene sequences from one cell to another, over various distances. The ability of eoDNA to partake in horizontal gene transfer makes it an important facet in the field of epigenetic variation. Clinical implementation of eoDNA diagnostics requires that all of the subgroups of eoDNA be properly investigated. It is suggested that eoDNA is the result of the metabolic fraction of DNA that is released by the cell. Various observations indicate that eoDNA may also be incorporated into the genome of a cell, from where it may affect cell function. Therefore horizontal gene transfer in higher organisms is a real possibility. In this study, variations and increases in eoDNA levels over time correlate with stressors that are subjected to 143B human osteosarcoma cells. It seems viable to assume that a stressor is met by a change in the molecular machinery of a cell, required to neutralise the onset of metabolic instability. This may be done by amplification of necessary cistrons, producing metabolic DNA, that may then be observed after its release as eoDNA. The presence of hydrolysing enzymes gives an updated real time picture of the state of eoDNA. The eogenics hypothesis emanating from this study, suggests that amplification and horizontal transfer of cistrons affect tissue and organ function over long periods of time, in order for an organism to evolve one or more a specialized genomes. / Thesis (M.Sc. (Biochemistry))--North-West University, Potchefstroom Campus, 2011.

The diagnostic value of extracellular occurring DNA (eoDNA) is limited by our lack of understanding its biological function. eoDNA exists in a number of forms, namely vesicle bound DNA, histone/DNA complexes or nucleosomes and virtosomes. These forms of DNA can also be categorized under the terms circulating DNA, cell free DNA, free DNA and extracellular DNA. The DNA can be released by means of form–specific mechanisms and seem to be governed by cell cycle phases and apoptosis. Active release is supported by evidence of energy dependant release mechanisms and various immunological– and messenger functions. Sequencing has shown that eoDNA sequences present in the nucleome reflects traits and distribution of genome sequences and are regulated by ways of release and/or clearance. eoDNA enables the horizontal transfer of gene sequences from one cell to another, over various distances. The ability of eoDNA to partake in horizontal gene transfer makes it an important facet in the field of epigenetic variation. Clinical implementation of eoDNA diagnostics requires that all of the subgroups of eoDNA be properly investigated. It is suggested that eoDNA is the result of the metabolic fraction of DNA that is released by the cell. Various observations indicate that eoDNA may also be incorporated into the genome of a cell, from where it may affect cell function. Therefore horizontal gene transfer in higher organisms is a real possibility. In this study, variations and increases in eoDNA levels over time correlate with stressors that are subjected to 143B human osteosarcoma cells. It seems viable to assume that a stressor is met by a change in the molecular machinery of a cell, required to neutralise the onset of metabolic instability. This may be done by amplification of necessary cistrons, producing metabolic DNA, that may then be observed after its release as eoDNA. The presence of hydrolysing enzymes gives an updated real time picture of the state of eoDNA. The eogenics hypothesis emanating from this study, suggests that amplification and horizontal transfer of cistrons affect tissue and organ function over long periods of time, in order for an organism to evolve one or more a specialized genomes. / Thesis (M.Sc. (Biochemistry))--North-West University, Potchefstroom Campus, 2011.

In cardiovascular disease the repair response is insufficient to restore blood flow, leading to the death of muscle and loss of tissue function. Therefore, strategies to augment the endogenous cell response and its effects may help improve tissue recovery and function. In this study we explored the use of tissue-engineered collagen matrices for augmenting endogenous regenerative processes after myocardial infarction. Treatment with the sLeX-collagen matrix reduced inflammation and apoptosis and had a positive regenerative effect on the infarcted mouse heart, through improved vascular density and possibly enhanced cardiomyogenesis. Additionally, we investigated the effects of cryopreservation on generating circulating angiogenic cells (CACs) from peripheral blood mononuclear cells (PBMCs), as a potential source of stem cells that could be used in combination with our collagen scaffold. Our findings show that despite PBMCs experiencing phenotypic changes after cryopreservation, they may still be used to generate the same therapeutic CACs as freshly procured PBMCs.

Orientador: Adriana Polachini Valle / Resumo: Introdução: O câncer de próstata (CP) é o mais incidente entre os homens em todas as regiões do Brasil. A detecção e caracterização de células tumorais circulantes (CTCs) tem sido apontada como uma alternativa para melhor compreensão da biologia dos tumores, incluindo câncer de próstata. Objetivo: Este estudo tem como objetivo avaliar a detecção de CTCs em pacientes com tumor de próstata localizado e metastático por teste rápido de filtração celular. Metodologia: Foram incluídos pacientes com diagnóstico anatomopatológico de câncer de próstata ou neoplasia intraepitelial prostática. Os dados demográficos, laudos anatomopatológicos e de Cintilografia Óssea e valores do antígeno prostático especifico ( PSA) foram obtidos pelo estudo dos prontuários médicos dos pacientes. Os pacientes foram classificados como portadores de tumor metastático quando apresentavam evidência de imagem metastática pela Cintilografia Óssea. As CTS foram isoladas por teste rápido de filtração celular com posterior imunocitoquímica utilizando-se anticorpos monoclonais anti-PSA para caracterização câncer de próstata específica das células. Resultados: As CTCs foram detectadas em 9 dos 21 pacientes (43%) com positividade de 60% no grupo metastático e 36% no grupo de tumor localizado. Não foram observadas associações entre os valores de PSA e tratamento instituído com a detecção de CTCS. Discussão: A positividade das CTCs no presente estudo mostrou-se semelhante aos dados da literatura, embora possam ser ci... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Introduction: Prostate cancer (PC) is the most frequent among men in all regions of Brazil. The detection and characterization of circulating tumor cells (CTCs) has been pointed out as an alternative for a better understanding of the biology of tumors, including prostate cancer. Objective: This study aims to evaluate the detection of CTCs in patients with localized and metastatic prostate tumor by rapid cell filtration test. Methodology: Patients with anatomopathological diagnosis of prostate cancer or prostatic intraepithelial neoplasia were included. Demographic data, anatomopathological and bone scintigraphy reports and prostate specific antigen (PSA) values were obtained by the study of patients' medical records. Patients were classified as having metastatic tumor when they presented evidence of metastatic image by Bone Scintigraphy. The CTS were isolated by rapid cell filtration test with subsequent immunocytochemistry using anti-PSA monoclonal antibodies for cell-specific prostate cancer characterization. Results: CTCs were detected in 9 of the 21 patients (43%) with 60% positivity in the metastatic group and 36% in the localized tumor group. No associations were observed between PSA values and treatment established with CTCS detection. Discussion: The positivity of the CTCs in the present study was similar to the data in the literature, although some limitations of the study may be cited, such as a small number of patients included, difficulties encountered by research... (Complete abstract click electronic access below) / Mestre

Circulating tumor cells (CTCs) represent a systemic phase of the localised cancer disease. They can be distinguished and enriched from the peripheral blood and so from the surrounding leukocytes by either physical properties (e.g., density and size) or biological properties (e.g., expression of epithelial proteins such as EpCAM or cytokeratins) and are usually further characterized by immunostaining or RT-PCR assays. Selecting patients with the risk of disease relaps at the time of diagnosis is crucial for clinicians in deciding who should, and who should not, receive adjuvant chemotherapy. We know that CTCs are strong prognostic factor in patients with metastatic as well as localized breast cancer (BC). It is also known that the prognostic power of circulating tumor cells in women with BC is independent from the standard prognostic indicators. Testing of CTCs known recently as "liquid biopsy" could be informative not only as predictor of the disease relapse, but also as the predictor of therapy effectiveness. The clinical use of CTCs must be strictly encouraged by clinical trials results. Monitoring of CTCs in time could zoom in the mechanism of therapy resistance and/or may provide the identification of new druggable targets. The purpose of my work was therefore to assess the CTCs positivity rate...