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1
Farzi, Mohsen. "Bone ageing and osteoporosis : automated DXA image analysis for population imaging." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22477/.
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2
Groll, Emily D. "Comparison of anthropometric and DXA measurements of regional body fat." Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1398712.
Повний текст джерелаАнотація:
Purpose: The primary purpose of this research study was to assess the degree of agreement between simple anthropometric measurements (i.e. body mass index, waist circumference, hip circumference, and waist-to-hip ratio) and the measures of regional adiposity, with a primary focus on the androidlgynoid ratio, assessed using dual energy x-ray absorptiometry (DXA). This secondary purpose of the study was to identify any significant correlations between the measures of regional adiposity, physical activity, and cardiovascular risk factors. Methods: Forty-eight subjects, 19 males (48.7 ± 16.9 years) and 29 females (43.6 ± 16.2 years), volunteered to participate in this study. Subjects underwent laboratory testing compromised of resting blood pressure, blood lipid analysis, waist & hip circumference, total body DXA scan, and a one week physical activity assessment. Results: Significant correlations were observed between body mass index and region body fat % (r = 0.84, 0.79), waist circumference and android fat % (r = 0.79, 0.75), and waist-to-hip ratio and androidlgynoid ratio (r = 0.72, 0.61) for men and women, respectively. Fasting insulin was correlated with region body fat %, android body fat %, trunk body fat %, and the android/gynoid ratio. The android/gynoid ratio was correlated with high density lipoproteins, very low density lipoproteins, triglycerides, and fasting glucose. There was a statistically significant negative relationship observed between average steps per day and body mass index, waist circumference, hip circumference, region body fat %, android body fat %, and trunk body fat %. Conclusions: This study found that there are strong relationships between simple anthropometric measures and regional body fat measures from the DXA. According to the data in the present study, body mass index, waist circumference, and waist-to-hip ratio provide simple yet sensitive methods for the estimation of regional body fat in Caucasian males and females. In addition, this study found significant correlations between measures of the blood lipid profile, physical activity, and both simple anthropometric and DXA measures of regional body fat. Key words: android fat, body mass index, dual-energy x-ray absorptiometry, gynoid fat, obesity, waist circumference.School of Physical Education, Sport, and Exercise Science
3
Jennings, Dalton James. "USE OF BODY COMPOSITION IMAGING TO CALCULATE 3-D INERTIAL PARAMETERS FOR INVERSE DYNAMIC ANALYSIS OF YOUTH PITCHING ARM KINETICS." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2122.
Повний текст джерелаАнотація:
The objectives of this study were to 1) calculate participant-specific segment inertial parameters using dual energy X-ray absorptiometry (DXA) data (referred to as full DXA-driven parameters) and compare the pitching arm kinetic predictions using full DXA-driven inverse dynamics vs scaled, DXA mass-driven (using DXA masses but scaled centers of mass and radii of gyration), and DXA scaled inverse dynamics(ID) (using the full DXA-driven inertial parameters averaged across all participants), 2) examine associations between full DXA-driven kinetics and body mass index (BMI) and 3) examine associations between full DXA-driven kinetics and segment mass index (SMI). Eighteen 10- to 11- year-olds pitched 10 fastballs. DXA scans were conducted and examined to obtain 3D inertial parameters of the upper arm, forearm, and hand. Full DXA-driven and scaled inertial parameters were compared using paired t-tests. Pitching arm kinetic predictions calculated with the four methods (i.e. scaled ID, DXA mass-driven ID, full DXA-driven ID, and DXA scaled ID) were compared using a repeated measures ANOVA with Tukey post-hoc tests. The major results were that 1) full DXA-driven participant specific inertial parameters differed from scaled inertial parameters 2) kinetic predictions significantly varied by method and 3) full DXA-driven ID predictions for shoulder compression force and shoulder internal rotation torque were significantly associated with BMI and/or SMI.
4
Weigand, Anna Christine [Verfasser], and Armin [Akademischer Betreuer] Scholz. "Phenotyping of the visceral adipose tissue using Dual Energy X-ray Absorptiometry (DXA) and Magnetic Resonance Imaging (MRI) in pigs / Anna Christine Weigand ; Betreuer: Armin Scholz." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2021. http://d-nb.info/1230754849/34.
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5
Nelson, McKenzie Louise. "Predictions of Radius Bending Strength by Radius Stiffness, Mineral, and Ulna Mechanical Properties." Ohio University Art and Sciences Honors Theses / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ouashonors1492615282195033.
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6
Saleem, Afsah. "Machine learning for computer-aided diagnostics from complex medical images." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2025. https://ro.ecu.edu.au/theses/2927.
Повний текст джерелаАнотація:
Machine learning has significantly transformed medical image analysis in the current age of artificial intelligence offering vast potential in improving disease diagnosis and management. Cardiovascular diseases (CVDs) are among the leading cause of global mortality, emphasizing the need for early detection for effective intervention and prevention. Abdominal Aortic Calcification (AAC) is an early indicator and contributor to Atherosclerotic Cardiovascular Diseases (ASCVDs) and is commonly assessed through imaging modalities such as computed tomography (CT), X-rays, and Dual-energy X-ray Absorptiometry (DXA). Among these, lateral spine DXA scans, commonly used for osteoporosis screening, offer a cost-effective and low-radiation opportunity for opportunistic CVD risk assessment. Despite advancements in medical imaging technologies, AAC evaluation still relies on manual interpretation by trained clinicians, a process that is labor-intensive, subjective, and prone to variability. Automating the process of AAC quantification can address these challenges and enable consistent, early screening for CVD risk.
This research presents robust machine-learning frameworks for the automated and accurate prediction of the AAC-24 score and its classification into relevant risk classes (low, moderate, and high). First, we explore deep feature ensembling methods to develop a deep feature fusion network for AAC-4 scoring using regression loss. However, its performance was limited by class ambiguities from inter-class similarities, intra-class variations, and low resolution VFA DXA artifacts. To mitigate this problem, we formulate AAC-24 scoring as an ordinal regression problem and propose a novel supervised contrastive ordinal learning (SCOL) framework. SCOL leverages a label-dependent distance metric to capture the ordinal nature of AAC labels. Using SCOL, we develop a Dual-encoder Contrastive Ordinal Learning (DCOL) framework to learn contrastive ordinal representation at global and local levels, improving feature separability and class diversity in the latent space among the AAC-24 categories. Clinical validation demonstrated a strong association between ML-AAC-24 scores and ASCVD risk, with substantial agreement between ML predictions and expert assessments. To enhance generalizability across different imaging modalities, SCOL framework is further explored for lateral spine X-rays via cross-domain fine-tuning, enhancing its utility in diverse clinical settings.
To strengthen this work on highly imbalanced disease grading medical datasets, a prototype-based learning approach is incorporated within the SCOL framework to develop a generic disease grading system. The framework is evaluated on public datasets for diabetic retinopathy grading and breast cancer staging, demonstrating its ability to learn robust, ordinal-aware prototypes that generalize across diverse medical imaging tasks. Additionally, to enhance the interpretability and reliability of automated systems in clinical diagnosis, we develop a context-aware ordinal learning framework for granular-level AAC-24 scoring. We address the challenges of SCOl in handling class imbalance for ordinal regression tasks and introduce SCOL+. We explore SCOL+ in a multi-label setting to determine the extent of calcification in each section of the aorta to aid clinicians in making detailed and interpretable diagnoses.
In this thesis, the AAC algorithms are developed using five large clinical datasets obtained from machines with different manufactures, including patients from Australia, Canada, and the United States, spanning both male and female patients. In conclusion, as DXA scans are commonly captured in various clinical scenarios, this research offers a novel and opportunistic approach to cardiovascular disease detection and monitoring in clinical practice, potentially revolutionizing the way we approach CVD risk screening.
7
Gill, Martin. "DNA-binding ruthenium complexes : cellular imaging and cytotoxicity." Thesis, University of Sheffield, 2010. http://etheses.whiterose.ac.uk/1161/.
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8
Müller, Thomas. "Imaging of DNA and DNA-RAP1 assembly by STM, TEM and SFM /." [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10958.
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9
Domingues, Juan de Moraes. "Che Guevara : a m?dia como potencializadora do mito." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2008. http://tede2.pucrs.br/tede2/handle/tede/4357.
Повний текст джерелаАнотація:
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Previous issue date: 2008-12-10Este trabalho analisa a for?a de perman?ncia do mito de Che Guevara 40 anos depois de sua morte. Desde que foi morto na Bol?via, em outubro de 1967, Che se transformou em mito, a despeito de suas distintas vers?es e releituras ao longo do tempo. A famosa foto de Alberto Korda, reproduzida aos milhares nessas quatro d?cadas, se tornou uma esp?cie de totem ideol?gico, mas tamb?m uma imagem consumida por milhares de pessoas das mais diferentes maneiras. Esta disserta??o, portanto, se ocupa em verificar a trajet?ria deste mito e a for?a que o mant?m. Para isso, o estudo identifica ao menos quatro vari?veis que atuam no fortalecimento do mito de Che: a midi?tica, a ideol?gica, a imag?tica e a de consumo. Embora n?o ajam necessariamente de forma simult?nea e nem na ordem acima citada, ? este ciclo que retroalimenta o universo guevarista. ? importante notar que dentre as quatro vari?veis, ? a m?dia que, em seus diferentes suportes, potencializa as outras tr?s, impulsionando a imagem, o consumo e a ideologia de Che e seu mito.
10
Wei, Diming. "The beauty of DNA architecture : the design and applications in DNA nanotechnology /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CBME%202009%20WEI.
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11
Glover, Caroline. "Chiral ruthenium imaging probes for duplex and quadruplex DNA." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19548/.
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12
Bamford, Rosemary Anne. "Development of fluorophore-tagged DNA probes for cellular imaging applications." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6406/.
Повний текст джерелаАнотація:
Single nucleotide polymorphisms (SNPs) are single base variations in DNA which give genetic variation. However, SNPs can also be linked to the development of certain diseases. Modified oligonucleotides used to probe biological changes and processes have become an important focus of scientific research. Fluorescent tagging of DNA can be used to sense SNPs in DNA targets through differences in emission intensity on the formation of a duplex. An anthracene-tagged DNA probe developed by Tucker \(et\) \(al\). is able to discriminate between a fully complementary DNA target sequence and one with a single base difference. This thesis describes how SNP sensing with anthracene-tagged DNA has been extended to SNPs in RNA targets and sequences associated with Alzheimer's disease. Finally, a new dual fluorophore DNA probe was designed for SNP sensing via FRET.
13
Vencio, Ricardo Zorzetto Nicoliello. "Análise estatística na interpretação de imagens: microarranjos de DNA e ressonância magnética funcional." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/95/95131/tde-16032007-164424/.
Повний текст джерелаАнотація:
O objetivo deste trabalho é apresentar os métodos originais em Bioinformática desenvolvidos para a análise estatística na interpretação dos dados de duas técnicas baseadas em imagens: a técnica de microarranjos de DNA e a técnica de ressonância magnética funcional. O interesse principal é abordar essas técnicas experimentais quando enfrenta-se uma situação clara de amostras escassas, isto é, quando existem relativamente poucas observações experimentais do fenômeno estudado, sendo a análise individual/personalizada o representante extremo desta situação, que tem que ser resolvida. Para tanto, opta-se pelo uso da Inferência Bayesiana no contexto da Teoria da Decisão sob Incerteza, implementada computacionalmente sob o arcabouço dos Sistemas de Suporte à Decisão. Ambas as tecnologias estudadas produzem dados complexos, baseados na interpretação das diferenças entre imagens obtidas da resposta do sistema a um estímulo e da resposta numa situação controle. O resultado deste trabalho é o desenvolvimento de dois sistemas de suporte à decisão, chamados HTself e Dotslashen, para a análise de dados de microarranjos e ressonância magnética funcional, respectivamente; e de seus métodos matemáticos/computacionais subjacentes. Os sistemas desenvolvidos extraem conhecimento racional de bancos-de-dados normativos, através de modelos matemáticos específicos, contornando então o problema de amostras escassas. Finalmente, neste trabalho são descritas aplicações a problemas reais, para destacar a utilidade dos sistemas de suporte à decisão desenvolvidos nas áreas de Biologia Molecular e Neuroimagem Funcional.The goal of this work is to present the novel Bioinformatics methods that were developed aiming the statistical analysis of two image-based techniques: DNA microarrays and functional magnetic resonance imaging. The main interest is to approach these experimental techniques in small sample size situations, i.e., when there are relatively few experimental observations of the phenomena of interest, for which the case of single subject/datum analysis is its most extreme. In order to approach these problems we chose to use Bayesian Inference in the context of the Decision Theory under Uncertainty, computationally implemented under the Decision Support Systems framework. Both technologies produce complex data, based on the interpretation of differences between images from the response to a given stimulus and the control situation. The result of this work is the development of two decision support systems, called HTself and Dotslashen, to analyze microarray and functional magnetic resonance imaging data, respectively; and the underling mathematical and computational methods. These systems use the rational knowledge from normative databases implemented in specific mathematical models, overcoming the problem of small sample size. Finally, in this work it is described applications to real problems in order to stress the utility for Molecular Biology and Functional Neuroimaging of the developed decision support systems.
14
Hards, Andrew. "The combined AFM manipulation and fluorescence imaging of single DNA molecules." Diss., lmu, 2004. http://nbn-resolving.de/urn:nbn:de:bvb:19-25373.
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15
Chen, Changsheng Verfasser], and Maximilian [Akademischer Betreuer] [Ulbrich. "Fluorescently labeled DNA probe in STORM imaging and single-molecule protein labeling." Freiburg : Universität, 2019. http://d-nb.info/1187658545/34.
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16
Chen, Changsheng [Verfasser], and Maximilian [Akademischer Betreuer] Ulbrich. "Fluorescently labeled DNA probe in STORM imaging and single-molecule protein labeling." Freiburg : Universität, 2019. http://d-nb.info/1187658545/34.
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17
Murphy, Jeffrey N. "Electrochemical in situ investigation of thiolate DNA monolayers on gold with fluorescence imaging." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2784.
Повний текст джерелаАнотація:
DNA-modified surfaces have been widely studied for microarray and biosensor applications, in particular sequence-specific detection of DNA, for which electrochemical and optical signs can be produced. Variations in the organization and surface density of adsorbed DNA are known to affect the sensitivity and reliability of assays performed using such surfaces, however most measurements of such surfaces to date have little to no spatial resolution, limiting the information that can be gathered regarding the heterogeneity of the organization of adsorbed DNA molecules. We have applied in situ epi-fluorescence microscopic imaging in conjunction with electrochemical measurements to fluorescently labelled thiolate DNA, adsorbed on polycrystalline gold electrodes with a mercaptohexanol (MCH) passive layer. Spatially resolved information on the organization of adsorbed DNA on the surface is gathered within an area measuring 520by 730micrometres with a 0.96 micrometre resolution. The technique has enabled us to investigate "hotspots" (regions of anomalously bright fluorescence) and regional variation in fluorescence; since molecular fluorescence is quenched as a function of distance from the metal substrate, potential modulation with consequent DNA reorientation or layer specificity of the adsorption. Furthermore, an alternative means to the conventional preparation of thiolate-DNA / MCH monolayers has been developed. In this new method, a gold substrate passivated with MCH is subsequently immersed in an aqueous solution of 5'hexylthiol modified DNA. Through a ligand exchange process, DNA is immobilized forming a mixed MCH / DNA monolayer. Samples prepared via the new method display fewer hotspots and improved fluorescence switching of the DNA during electromodulation for samples made with single stranded (ss) DNA and with double stranded (ds) DNA. Measurement of the DNA surface concentration using ruthenium (III) hexaammine chloride with cyclic voltammetry for self assembled monolayers (SAMs) prepared via the new method are on the order of 1% of the maximum grafting density obtainable for both ssDNA and dsDNA by conventional methods.
18
Helal, Belal M. 1971. "UV imaging of electrophoresis gels : a non-invasive, nanogram level quantification of DNA." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87307.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (leaves 183-185).
by Belal M. Helal.
S.M.
19
Bellassai, Noemi. "Surface Plasmon Resonance Imaging Biosensors for Cancer Diagnosis: Detection of Circulating Tumor DNA." Doctoral thesis, Università di Catania, 2018. http://hdl.handle.net/10761/4165.
Повний текст джерелаАнотація:
This doctoral thesis focused on the realization of Surface Plasmon Resonance Imaging (SPRI) biosensor for the rapid, simple and label-free detection of single point mutations in the KRAS gene, standard actionable cancer biomarkers for colorectal cancer, in human plasma samples. Initially, the SPRI assay included the immobilization of specific peptide nucleic acid (PNA) probes onto the gold sensor to ensure the hybridization reaction of PNA-DNA complexes. The spatially controlled immobilization of PNA probes has been obtained by injecting PNA wild-type and PNA mutated solutions into a microfluidic system coupled to SPR sensor chip. The extremely low concentration of genomic DNA required an improvement of SPRI detection capabilities, by using functionalized gold nanoparticles to amplify the hybridization signal between target analytes and corresponding PNA probes. Three representative single-point mutations, gDNA G12D, G12V and G13D, have been successfully detected.
After preliminary results of nanoparticle-enhanced SPRI assay, a mixed-charge polymer based on Poly-L-lysine (PLL) polypeptide backbone modified with an anionic peptide, connected via a nonionic OEG spacer, has been synthesized in order to achieve control over the charge distribution of PLL-coated surfaces, and thus the antifouling property. The PLL backbone has been functionalized with different percentages (y%) of maleimide-OEG-NHS ester chains (PLL-mal(y%), from 13% to 26%), and the anionic oligopeptide CEEEEE, composed of one cysteine (C) and five glutamic acids (E), with a short sequence to limit the thickness of the mixed-charge polymer antifouling coating, has been attached to the maleimide units through the thiol maleimide Michael-type addition. The grafting density has been varied to tune the balance of charged groups at polymer backbone. PLL-mal(y%)-CEEEEE surfaces have been characterized by water contact angle and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). Complementary acoustic (quartz crystal microbalance with dissipation, QCM-D) and plasmonic (surface plasmon resonance imaging, SPRI) techniques have been employed to monitor the adsorption of bovine serum albumin (BSA), used as standard protein solution, and diluted human plasma samples. Hence, a new nanoparticle-enhanced SPRI assay for circulating tumour DNA (ctDNA) detection in human plasma samples using PLL-mal(y%)-CEEEEE layer as the antifouling coating has been devised. The PNA probes and the anionic peptide have been attached to the maleimide units through the thiol maleimide reaction using a microfluidic system coupled to SPR sensor chip. The analysis of ctDNA G12D target in diluted human plasma samples (5 pg uL-1), collected from cancer patients and healthy donors, has been carried out using the conjugated AuNPs system, with a minimal sampling handling to avoid any contamination and disruption of the antifouling activity of PLL-mal(y%)-CEEEEE layer. The combined use of PLL-mal(y%)-CEEEEE as the antifouling layer with functionalized gold nanoparticles for the amplification of target detection overcomes the limiting factors related to the biosensor in the clinical field and offers an excellent ctDNA discrimination in the bloodstream at attomolar level.
20
BELLASSAI, NOEMI. "Surface Plasmon Resonance Imaging Biosensors for Cancer Diagnosis: Detection of Circulating Tumor DNA." Doctoral thesis, Università degli studi di Catania, 2018. https://hdl.handle.net/20.500.11769/549419.
Повний текст джерелаАнотація:
This doctoral thesis focused on the realization of Surface Plasmon Resonance Imaging (SPRI) biosensor for the rapid, simple and label-free detection of single point mutations in the KRAS gene, standard actionable cancer biomarkers for colorectal cancer, in human plasma samples. Initially, the SPRI assay included the immobilization of specific peptide nucleic acid (PNA) probes onto the gold sensor to ensure the hybridization reaction of PNA-DNA complexes. The spatially controlled immobilization of PNA probes has been obtained by injecting PNA wild-type and PNA mutated solutions into a microfluidic system coupled to SPR sensor chip. The extremely low concentration of genomic DNA required an improvement of SPRI detection capabilities, by using functionalized gold nanoparticles to amplify the hybridization signal between target analytes and corresponding PNA probes. Three representative single-point mutations, gDNA G12D, G12V and G13D, have been successfully detected. After preliminary results of nanoparticle-enhanced SPRI assay, a mixed-charge polymer based on Poly-L-lysine (PLL) polypeptide backbone modified with an anionic peptide, connected via a nonionic OEG spacer, has been synthesized in order to achieve control over the charge distribution of PLL-coated surfaces, and thus the antifouling property. The PLL backbone has been functionalized with different percentages (y%) of maleimide-OEG-NHS ester chains (PLL-mal(y%), from 13% to 26%), and the anionic oligopeptide CEEEEE, composed of one cysteine (C) and five glutamic acids (E), with a short sequence to limit the thickness of the mixed-charge polymer antifouling coating, has been attached to the maleimide units through the thiol maleimide Michael-type addition. The grafting density has been varied to tune the balance of charged groups at polymer backbone. PLL-mal(y%)-CEEEEE surfaces have been characterized by water contact angle and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). Complementary acoustic (quartz crystal microbalance with dissipation, QCM-D) and plasmonic (surface plasmon resonance imaging, SPRI) techniques have been employed to monitor the adsorption of bovine serum albumin (BSA), used as standard protein solution, and diluted human plasma samples. Hence, a new nanoparticle-enhanced SPRI assay for circulating tumour DNA (ctDNA) detection in human plasma samples using PLL-mal(y%)-CEEEEE layer as the antifouling coating has been devised. The PNA probes and the anionic peptide have been attached to the maleimide units through the thiol maleimide reaction using a microfluidic system coupled to SPR sensor chip. The analysis of ctDNA G12D target in diluted human plasma samples (5 pg uL-1), collected from cancer patients and healthy donors, has been carried out using the conjugated AuNPs system, with a minimal sampling handling to avoid any contamination and disruption of the antifouling activity of PLL-mal(y%)-CEEEEE layer. The combined use of PLL-mal(y%)-CEEEEE as the antifouling layer with functionalized gold nanoparticles for the amplification of target detection overcomes the limiting factors related to the biosensor in the clinical field and offers an excellent ctDNA discrimination in the bloodstream at attomolar level.
21
Zhu, Jinhao. "Uniquimer 3D, a software system for structural DNA nanotechnology design, analysis and evaluation /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?CSED%202008%20ZHU.
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22
Crane, Bryan Lee 1976. "DNA mutation detection via fluorescence imaging in a spatial thermal gradient, capillary electrophoresis system." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/88874.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001."February 2001."
Includes bibliographical references (leaves 122-126).
by Bryan Lee Crane.
S.M.
23
Clowsley, Alexander Harrington. "Optimisation and comparison of dSTORM and DNA-PAINT super-resolution for quantitative cardiac protein imaging." Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/33021.
Повний текст джерелаАнотація:
Fluorescence microscopy techniques, restricted by the diffraction limit of light, have seen a remarkable advancement in recent years. An approach called dSTORM (direct stochastic optical reconstruction microscopy) utilises the photoswitching capabilities of organic fluorophores when in the presence of special mounting media, the solution within which the sample is placed, to detect single molecule fluorescing events over time. The image that can be reconstructed from these events is not diffraction limited, but instead is limited by how well each event can be precisely localised. In Chapter 3 the importance of using a suitable mounting buffer in order to achieve super-resolution dSTORM is discussed in detail. A quantitative method for determining the reactivity of thiol dSTORM switching mountants was developed for use within the lab. Every fluorescent probe has different photophysical properties which can be manipulated by varying the composition of the switching buffer to enhance desirable qualities, such as; increased photon counts, faster switching rates, and longer survivability. In addition to investigating the effects of buffer composition the use of a near UV light-source was also explored as a means of manipulating the same properties to improve overall resolution and quality of the resulting images. A range of photoswitchable fluorescent dyes were tested including Alexa Fluor 660 which is a dye that to my knowledge has not been greatly tested for use in single molecule localisation microscopy by others to date. This dye performed strongly alongside the traditional Alexa Fluor 647 used for dSTORM imaging in optimal conditions. A relatively new approach to single molecule imaging which does not require the fluorophore to photoswitch, called DNA-PAINT (point accumulation for imaging in nanoscale topography), has been investigated throughout this thesis. This approach relies on the transient binding of small oligonucleotide sequences, called “Imagers”, to target docking strands anchored in positions of interest. These imagers have a photostable and bright fluorophore conjugated to the oligonucleotide. It is the transient immobilisation of the imager strand, as it binds to a fixed docking strand, which appears as stochastic blinks. The duration of these events, which can be extended by increasing the number of overlapping base pairs, is primarily responsible for improved localisation precision and therefore potentially overall resolution. At the end of Chapter 3 I compare this new pointillism microscopy approach, DNA-PAINT, with dSTORM using a set of custom-designed oligonucleotide sequences that allow both formats to be employed on the same target. The transient binding of small strands of oligonucleotides offers a far more controllable system for stochastic imaging. In Chapter 4 I use this superior approach to achieve greater resolution than other fluorescence techniques in biological samples, sufficient to visualise single ryanodine receptors (RyR). The RyR are extremely important in the contraction of muscle cells as they are capable of detecting transient changes to calcium concentration and are responsible for releasing large stores of calcium from the sarcoplasmic reticulum. With DNA-PAINT I observed that RyRs cluster into irregular arrays which contain significant gaps that are occupied by other proteins, including junctophilin (JPH). The stoichiometry of JPH with RyR varied cluster to cluster, exposing a new complexity in the regulation of RyRs. In Chapter 5, quantitative super-resolution is reliably achieved through the implementation of quantitative DNA-PAINT (qPAINT) within the Python Microscopy Environment (PYME) software. Quantitative measurements are possible because of the statistical predictability of DNA hybridisation and the near constant influx of fresh imager strands by diffusion. This results in limited photobleaching, a permanent dark state. The frequency with which a region of interest blinks is proportional to the number of binding sites available, and therefore the mean dark time between detected events is also inversely proportional. I validate my approach to qPAINT, which maintains the spatial information of individual structures, by using a DNA-origami test slide. Two distinguishable structures were present and an estimate for the ratio of available docking sites between them was satisfactorily established. I conclude that with this tool, molecule densities can be inferred and information about biological samples can be probed to new levels. The results of the full methodological approach to accomplish dual-colour super-resolution imaging of optically thick cardiac tissue, using both dSTORM and DNA PAINT techniques, is discussed in detail in Chapter 6. The current range of photoswitchable fluorophores limits the possible combination of molecular dyes for use with dSTORM and some compromise is made in their selection. For DNA-PAINT, the prospect of chromatic aberration is removed by imaging the same dye in subsequent rounds of imaging. The process, called Exchange-PAINT, allows the user to remove previously imaged imager strands, through a series of washes, and replace them with a complementary sequence for another target. I introduce the concept of using quencher strands to eliminate signal from unwanted imager sequences, accelerating their removal in samples of reduced diffusion and decreasing the risk of sample disturbance, in a process we termed Quencher Exchange-PAINT. Using this technique, I achieve superior super resolution results in optically thick samples. The results presented in this thesis are expected to (1) lead to a better understanding of the variables associated with single molecule localisation microscopy, (2) further reveal the complexity in cardiac protein distribution, (3) quantify relationships between co-localising proteins and other targets, and (4) apply DNA-PAINT to imaging in optically thick biological samples. This study shows promise for the future applications of the DNA-PAINT pointillism super-resolution method and its ability to investigate a multitude of biological questions.
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Bhat, Anayat [Verfasser]. "Live Cell Fluorescence Imaging of Nucleotide Dynamics : ATP Hydrolysis and DNA Damage Response / Anayat Bhat." Konstanz : KOPS Universität Konstanz, 2021. http://d-nb.info/1229351094/34.
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Lo, Chih-Cheng. "Dna electrophoresis in photopolymerized polyacrylamide gels on a microfluidic device." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2685.
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Cappellari, M?rcia Schmitt Veronezi. "As representa??es visuais do mal na comunica??o : imagin?rio moderno e p?s-moderno em imagens de A Divina Com?dia e do filme Constantine." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2007. http://tede2.pucrs.br/tede2/handle/tede/4323.
Повний текст джерелаАнотація:
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Previous issue date: 2007-12-17A presente tese disp?s-se a investigar as representa??es visuais do mal, definindo como focos de an?lise as ilustra??es de Gustave Dor? para A Divina Com?dia de Dante Alighieri e as imagens do filme Constantine, de Francis Lawrence. Para compreender como tais imagens se inseriram nos imagin?rios moderno e p?s-moderno, buscamos na Filosofia o conceito de mal, de modo a compreender sua complexidade e adaptabilidade. Encontramos na Hermen?utica de Profundidade de John B. Thompson (1995) um caminho metodol?gico considerado eficaz para proceder as investiga??es necess?rias e chegar aos resultados obtidos de modo a confirmar nossa tese. Atrav?s desta metodologia foi poss?vel analisar as imagens como formas simb?licas e a partir das an?lises formal-discursiva e s?cio-hist?rica proceder uma interpreta??o/reinterpreta??o do objeto pesquisado. Deste modo, cremos ter confirmado nossa proposta, chegando aos resultados de que as representa??es visuais do mal est?o sujeitas ao imagin?rio de seu tempo. Na modernidade, carregam uma forte carga moral decorrente do discurso racionalista e, na p?s-modernidade, s?o influenciadas por um modo de vida menos determinista, que provoca uma aproxima??o entre os conceitos de bem e de mal.
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INCORVAIA, ELISABETTA. "INSIGHT FROM AID-INDUCED DNA DAMAGE RESOLUTION: CELLULAR CONTEXT MATTERS." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/262377.
Повний текст джерелаАнотація:
When genome integrity is perturbed, surveillance and repair mechanisms are activated to restore genome integrity through high fidelity DNA repair. However, in some physiological situations, those mechanisms are channeled away from integrity towards mutations and recombinations. During the diversification of the immunoglobulin locus in B cells, Activation Induced Deaminase (AID) triggers the physiological introduction of mutations.
The current work was based on the observation that upon simple lesion generation, AID-induced deamination of a cytosine to uracil, the resolution by the molecular mechanism of DNA repair can lead to different outcomes. This homeostatic outcome, error-free or error-prone, is governed by specific cellular context and processes associated with DNA. To uncover the regulation of the pathway choice an in vitro system, named in vitro resolution (IVR), was developed. In the 1st phase of the IVR, AID was targeted to a DNA plasmid for uracil lesion generation. In the 2nd phase, a cellular extract resolved the lesions via Base Excision Repair [BER, divided in short patch (SP)-BER or long patch (LP)-BER] or Mismatch Repair (MMR). The quantitative nature of the IVR provided a novel means to precisely quantitate the contribution of each single DNA repair pathway. This set-up allowed us to evaluate how different cellular environments influenced the choice. Cell origins presented quantitative differences in DNA repair kinetics: a) overall sensitivity, b) non-B cells activating non-canonical MMR first, c) B cells activating SP-BER first, and d) LP-BER is significantly activated only in B cells. To understand the possible molecular mechanisms, we analysed single components known to influence DNA repair, such as transcription, protein availability, and chromatin. Changing the DNA substrate to either prefer or avoid forming nucleosomes, we uncovered significant changes in AID deamination preference and in DNA repair pathway choice. DNA with nucleosome favourable base-stacking preferred LP-BER, while non-nucleosome stacked DNA preferred SP-BER and MMR. Overall our findings provide novel insight into the cellular context that can influence DNA repair. The use of B cells and cancer cell lines can recapitulate in vivo Ig locus diversification, and our findings have a direct bearing in understanding mechanisms of tumorigenesis.
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Jones, Jeffry Alexander. "Coulostatic binding of plasmid DNA on chemically modified gold surfaces for imaging by scanning tunneling microscopy." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/30257.
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Ferreira, Carlos André Marques Viana. "Peer-to-peer network for medical imaging." Master's thesis, Universidade de Aveiro, 2010. http://hdl.handle.net/10773/5004.
Повний текст джерелаАнотація:
Mestrado em Engenharia de Computadores e TelemáticaNos últimos anos, a imagem médica em formato digital tem sido uma ferramenta cada vez mais importante quer para o diagnóstico médico quer para o auxílio ao tratamento. Assim, equipamentos de aquisição digital e repositórios de imagem médica são cada vez mais comuns em instituições de saúde, podendo até haver mais que um repositório numa instituição. No entanto, esta proliferação de repositórios leva a que a informação esteja dispersa nos vários locais. Esta dispersão da informação juntamente com as diferenças no armazenamento entre instituições são claros obstáculos à pesquisa e acesso integrado a essa informação. Esta dissertação visa o estudo da tecnologia Peer-to-Peer de forma a minimizar os problemas associados à dispersão e heterogeneidade da informação.
In the last years, digital medical imaging has been an increasingly important tool for both medical diagnostic and treatment assistance. Therefore, digital image acquisition equipments and medical imaging repositories are more and more common in a healthcare institution, being possible even more than one repository in one institution. However, this proliferation of repositories leads to dispersion of data between many places. This data dispersion associated with differences in the data storage between institutions are evident obstacles to the search for medical data. This dissertation aims to the study of the Peer-to- Peer technology in order to minimize the problems related to the dispersion and heterogeneity of medical data.
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Zahir, Sheba Adam. "Evaluating the efficacy of DNA repair biomarkers to assess human cell response to chemotherapy using imaging flow cytometry." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/7768.
Повний текст джерелаАнотація:
Chemotherapy and radiotherapy are widely accepted as common forms of treatment for cancers. The majority of cancer patients receive chemotherapy alone or in combination with radiotherapy. Most chemotherapeutic drugs cause DNA damage to the rapidly dividing cancer cells but normal cells are also damaged in the process. Therefore DNA repair levels in tumour and normal cells may determine the success of the treatment. The aim of this work was to evaluate the use of DNA repair biomarkers for assessing responses to chemotherapeutic drugs. The novel technique of imaging flow cytometry was employed to analyse the induction and resolution of γ-H2AX and RAD51 DNA repair biomarkers in DNA repair normal cell lines MRC5-SV1 and NB1-HTERT, an ATM-deficient cell line AT5BIVA (derived from an Ataxia Telangiectasia patient) and an XPF-deficient cell line GM08437B. Two cell lines were also developed, MRC5-SV1R and NB1-HTERTR which had been made resistant to HN2. A range of chemotherapeutic drugs, Adriamycin, Cisplatin and Nitrogen Mustard which have different modes of action were examined in this work. We have demonstrated distinct differences in γ-H2AX and RAD51 foci induction and resolution between the two DNA repair normal cell lines following exposure to different chemotherapeutic drugs. Additionally, it was demonstrated that both the resistant and sensitive cell lines have elevated γ-H2AX and RAD51 expression profiles in comparison to the parental cell lines over a 48 hour period post treatment with the cross-linking agent HN2. It is concluded that while both the γ-H2AX and Rad51 biomarkers may be useful for determining chemotherapeutic response, a larger cohort of cell lines and tumour samples is required for further analysis.
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Fries, Maximilian Werner. "Multiplexed biochemical imaging reveals the extent and complexity of non-genetic heterogeneity in DNA damage-induced caspase dynamics." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273868.
Повний текст джерелаАнотація:
Genetically identical cells show a heterogeneous response to a multitude of signals such as growth factors and DNA damage. While this heterogeneity has been shown to be a major determinant of treatment success in several diseases including cancer, little is known about how differences in biochemical signalling networks underlie such heterogeneity. State-of-the-art methodologies to study biochemical networks are often invasive and enable to quantify biochemical events only on cell populations or at a single point in time for a single cell, and therefore, cannot adequately quantify the fast, asynchronous and heterogeneous responses. In order to address these limitations, we have developed a unique sensing platform based on fluorescence lifetime imaging microscopy (FLIM) capable to multiplex at least three biosensors by utilizing Förster Resonance Energy Transfer (FRET) efficiently. After an overall introduction in Chapter 1, I describe the rational design and characterization of novel FRET pairs aiming to utilize the visible spectrum efficiently in combination with FLIM in Chapter 2. We combined blue, green and red donor fluorescent proteins that are excited at the same wavelength (840 nm for two-photon excitation) with genetically encoded quenchers, i.e. non-fluorescent chromoproteins as acceptors. This sensing platform enables the simultaneous detection of three biochemical reactions within single living cells providing new opportunities to characterize and understand non-genetic heterogeneity. In Chapter 3, I will demonstrate the first application of this novel platform by studying the activity of three key enzymes in DNA damage-induced cell death, caspase-2, -3, and -9. We confirm the heterogeneous nature of Cisplatin-induced cell death in genetically identical cells but reveal the existence of at least three subpopulations of cells characterized by distinct caspase dynamics. By combining biochemical and morphological information we infer the existence of different biochemical network topologies that are associated with alternative death phenotypes each cell adopts, such as apoptosis and programmed necrosis. Finally, deconvolution of cellular populations and direct measurement of a three-node caspase network - formerly impossible - permitted us to design perturbations of cell fate choices utilizing clinically relevant inhibitors. These perturbations resulted in changes in cell fate in response to Cisplatin, a clinically desirable outcome that suggests new avenues for combinatorial drugging and a new strategy to reveal cancer vulnerabilities that may be otherwise confounded by typical genetic and non-genetic heterogeneity.
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Douthwright, Stephen. "A Tale of Two Projects: Basis for Centrosome Amplification after DNA Damage and Practical Assessment of Photodamage in Live-Cell Imaging: A Dissertation." eScholarship@UMMS, 2015. https://escholarship.umassmed.edu/gsbs_diss/732.
Повний текст джерелаАнотація:
This thesis comprises two separate studies that focus on the consequences of cellular damage. The first investigates the effects of DNA damage on centriole behavior and the second characterizes phototoxicity during live-cell imaging.
Cancer treatments such as ionizing radiation and/or chemotherapeutic DNA damaging agents are intended to kill tumor cells, but they also damage normal proliferating cells. Although centrosome amplification after DNA damage is a well-established phenomenon for transformed cells, it is not fully understood in untransformed cells. The presence of extra centrosomes in normal cell populations raises the chances of genomic instability, thus posing additional threats to patients undergoing these therapies. I characterized centriole behavior after DNA damage in synchronized untransformed (RPE1) human cells. Treatment with the radiomimetic drug, Doxorubicin, prolongs G2 phase by at least 72hrs, where 52% of cells display disengaged centrioles and 10% contain extra centrioles. This disengagement is mediated by Plk and APC/C activities both singly and in combination. Disengaged centrioles are associated with maturation markers suggesting they are capable of organizing spindle poles. Despite the high incidence of centriole disengagement, only a small percentage of centrioles reduplicate due to p53/p21 dependent inhibition of Cdk2 activity. Although all cells become prolonged in G2 phase, 14% eventually go through mitosis, of which 26% contain disengaged or extra centrioles.
In addition to cancer treatments, cellular damage can be acquired from various external conditions. Short wavelengths of light are known to be toxic to living cells, but are commonly used during live-cell microscopy to excite fluorescent proteins. I characterized the phototoxic effects of blue (488nm) and green (546nm) light on cell cycle progression in RPE1. For unlabeled cells, I found that exposure to green light is far less toxic than blue light, but is not benign. However, the presence of fluorescent proteins led to increased sensitivity to both blue and green light. For 488nm irradiations, spreading the total irradiation durations out into a series of 10s pulses or conducting single longer, but lower intensity, exposures made no significant changes in phototoxicity. However, reducing oxidative stress by culturing cells at physiological (~3%) oxygen, or treatment with a water-soluble antioxidant, Trolox, greatly improved the cells tolerance to blue light.
Collectively, my work offers an explanation for centrosome amplification after DNA damage and demonstrates the importance of proper centriole regulation in untransformed human cells. Further, it provides a practical assessment of photodamage during live-cell imaging.
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Douthwright, Stephen. "A Tale of Two Projects: Basis for Centrosome Amplification after DNA Damage and Practical Assessment of Photodamage in Live-Cell Imaging: A Dissertation." eScholarship@UMMS, 2004. http://escholarship.umassmed.edu/gsbs_diss/732.
Повний текст джерелаАнотація:
This thesis comprises two separate studies that focus on the consequences of cellular damage. The first investigates the effects of DNA damage on centriole behavior and the second characterizes phototoxicity during live-cell imaging.
Cancer treatments such as ionizing radiation and/or chemotherapeutic DNA damaging agents are intended to kill tumor cells, but they also damage normal proliferating cells. Although centrosome amplification after DNA damage is a well-established phenomenon for transformed cells, it is not fully understood in untransformed cells. The presence of extra centrosomes in normal cell populations raises the chances of genomic instability, thus posing additional threats to patients undergoing these therapies. I characterized centriole behavior after DNA damage in synchronized untransformed (RPE1) human cells. Treatment with the radiomimetic drug, Doxorubicin, prolongs G2 phase by at least 72hrs, where 52% of cells display disengaged centrioles and 10% contain extra centrioles. This disengagement is mediated by Plk and APC/C activities both singly and in combination. Disengaged centrioles are associated with maturation markers suggesting they are capable of organizing spindle poles. Despite the high incidence of centriole disengagement, only a small percentage of centrioles reduplicate due to p53/p21 dependent inhibition of Cdk2 activity. Although all cells become prolonged in G2 phase, 14% eventually go through mitosis, of which 26% contain disengaged or extra centrioles.
In addition to cancer treatments, cellular damage can be acquired from various external conditions. Short wavelengths of light are known to be toxic to living cells, but are commonly used during live-cell microscopy to excite fluorescent proteins. I characterized the phototoxic effects of blue (488nm) and green (546nm) light on cell cycle progression in RPE1. For unlabeled cells, I found that exposure to green light is far less toxic than blue light, but is not benign. However, the presence of fluorescent proteins led to increased sensitivity to both blue and green light. For 488nm irradiations, spreading the total irradiation durations out into a series of 10s pulses or conducting single longer, but lower intensity, exposures made no significant changes in phototoxicity. However, reducing oxidative stress by culturing cells at physiological (~3%) oxygen, or treatment with a water-soluble antioxidant, Trolox, greatly improved the cells tolerance to blue light.
Collectively, my work offers an explanation for centrosome amplification after DNA damage and demonstrates the importance of proper centriole regulation in untransformed human cells. Further, it provides a practical assessment of photodamage during live-cell imaging.
34
Park, Daniel Joseph. "B1 Mapping for Magnetic Resonance Imaging." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5750.
Повний текст джерелаАнотація:
Magnetic Resonance Imaging (MRI) is a non-ionizing form of medical imaging which has practical uses in diagnosing, characterizing, and studying diseases in vivo. Current clinical practice utilizes a highly trained radiologist to view MR images and qualitatively diagnose, characterize, or study a disease. There is no easy way to compare qualitative data. That is why developing quantitative measures in MRI show promise. Quantitative measures of disease can be compared across a population, MRI sites, and over time. Osteoarthritis is one disease where those who have it may benefit from the development of quantitative MRI measures. Those benefits may include earlier diagnosis and treatment of the disease or treatment which may halt or even reverse the damage from the disease.The work presented in this dissertation focuses on analyzing and developing new methods of radiofrequency (B1) field mapping to improve quantitative MRI measures. The dissertation opens with an introduction and a brief primer on MRI physics, followed by an introduction to B1 and flip-angle mapping in MRI (Chapters 1-3). Chapter 4 presents a careful statistical analysis of a recent and popular B1 mapping method, the Bloch-Siegert shift (BSS) method, along with a comparison of the technique to other common B1 mapping methods. The statistical models developed in chapter 4 are verified using both Monte Carlo simulation and actual MRI experiments in phantoms. Chapter 5 analyzes and details the potential errors introduced in B1 mapping when a 3D slab-selective excitation is employed. A method for correcting errors introduced by 3D slab-selective B1 mapping is then introduced in chapter 6, along with metrics to quantify the error involved. The thesis closes with a summary of other scientific contributions made by the author in chapter 7. The chapters comprising the bulk of the presented research (4-7) are briefly summarized below. Chapter 4, the statistical analysis of B1 mapping methods, demonstrates the effectiveness of deriving the B1 estimate from the phase of the MR image. These techniques are shown to perform particularly well in low signal-to-noise ratio (SNR) applications. However, there are benefits and drawbacks of each B1 mapping technique. The BSS method deposits a significant amount of radiofrequency (RF) power into the patient, causing a concern that tissue heating may occur. The Phase-Sensitive (PS) method of B1 mapping outperforms the other techniques in many situations, but suffers from significant sensitivity to off-resonance. The Dual-Angle (DA) method is very simple to implement and the analysis is straightforward, but it can introduce significant mean bias in the estimate. No B1 mapping technique performs well for all situations. Therefore, the best B1 mapping method needs to be determined for each situation. The work in chapter 4 provides guidance for that choice. Many B1 mapping techniques rely on a linear relationship between flip angle and transmit voltage. That assumption breaks down when a 3D slab-selective excitation is used. 3D slab-selective excitation is a common technique used to reduce the field-of-view (FOV) in MRI, which can directly reduce scan time. The problem with slab-selective excitation in conjunction with B1 mapping has been documented, but the potential errors in B1 estimation have never been properly analyzed across different techniques. The analysis in chapter 5 demonstrates that the errors introduced in B1 mapping using a slab-selective excitation in conjunction with the ubiquitous DA B1 mapping method can be significant. It is then shown that another B1 mapping technique, the Actual Flip Angle Imaging (AFI) method, doesn't suffer from the same limitation. The analysis presented in Chapter 6 demonstrates that some errors introduced by 3D slab-selective B1 mapping may be modeled and corrected allowing the use of 3D slab-selective excitation to reduce field-of-view, and potentially reduce scan time. The errors are modeled and corrected with a general numerical method using Bloch simulations. The general method is applied to the DA method as an example, but is general and could easily be extended to other methods as well. Finally, a set of metrics are proposed and briefly explored that can be used to better understand the topology and severity of errors introduced into B1 mapping methods. With a better understanding of the errors introduced, the need for correction can be determined. Chapter 7 details other significant ancillary contributions made by the author including: (1) presentation of a new B1 mapping method, the decoupled RF-pulse phase-sensitive B1 mapping method, which has potential for parallel transmit MRI; (2) demonstration of an ultra-short TE method which has potential for imaging Alzheimers brain lesions in vivo; (3) introduction of a new steady-state diffusion tensor imaging technique; (4) phase-sensitive B1 mapping in sodium is demonstrated, a feat not previously demonstrated; (5) a comparison between a dual-tuned and single-tuned sodium coil; (6) introduction of a water- and fat-separation technique using multiple acquisition SSFP; (7) an inter-site and inter-vendor quantitative MRI study is introduced; (8) a relaxation and contrast optimization for laryngeal imaging at 3T is introduced; and (9) diffusion imaging with insert gradients is introduced.
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Azevedo, Soares Andreia. "Imagining humans in the age of DNA : genetics and contemporary British fiction." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/11593.
Повний текст джерелаАнотація:
This thesis examines to what extent modern genetics has influenced novelists to adopt a more deterministic view of human beings. It has been claimed that molecular biology, behavioural genetics and evolutionary psychology have challenged traditional ideas about humankind. My hypothesis is that if gene-centred disciplines changed the way we see ourselves, then this would have implications for the literary novel, a genre that depends greatly on representations of humans. In analysing how genetics was incorporated in contemporary British fiction, I try to uncover the ways in which the human characters deal with – or are constrained or empowered by – scientific products or concepts. In addition, I seek to understand what novelists know and think about human genetics, and whether they believe it influenced their stories. Attention is also paid to novelists’ relationship with scientists’ cognitive authority. Specifically, I am interested in whether experts and scientific knowledge were positioned hierarchically above lay audiences and other forms of knowledge. To answer those questions, extended semi-structured interviews and textual analysis were chosen as main research methods. Six literary novels were selected for analysis. This corpus consists of: A.S. Byatt’s A Whistling Woman, Carole Cadwalladr’s The Family Tree, Margaret Drabble’s The Peppered Moth, Maggie Gee’s The Ice People, Simon Mawer’s Mendel’s Dwarf and David Mitchell’s Cloud Atlas. The main conclusion of this project is that novelists are able to incorporate ideas about genetics in their texts without simply perpetuating reductionist discourses. Literary novels offer several advantages compared to the expository writing: they are a flexible literary form; deal imaginatively with the human experience; and effortlessly accommodate multiple perspectives, open-ended questions and complex ideas such as doubt and ambiguity. As such, this genre affords the opportunity to explore contemporary science as a provisional, contingent and socially-embedded endeavour.
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Badillo, Ramirez Isidro. "Functional dna nanostructures for in vitro biosensing in live cells." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7282/.
Повний текст джерелаАнотація:
DNA is a fascinating biomolecule that is well known for its genetic role in living systems. The emerging area of DNA nanotechnology provides an alternative view that exploits unparallel self-assembly ability of DNA molecules for material use of DNA. Although many reports exist on the results of DNA self-assembling systems, still few of them focus on the in vitro study about the function of such DNA nanostructures in live cells. Due to this, there are still a limited research about the in vitro functionality of such designs. To address an aspect of this issue, we have designed, synthesized and characterized two multifunctional fluorescencent nanobiosensors by DNA self-assembling. Each structure was designed and implemented to be introduced in live cells in order to give information on their functioning in real-time.
Computational tools were used in order to design a graphic model of two new DNA motifs and also to obtain the specific sequences to all the ssDNA molecules. By thermal self-assembly techniques we have successfully synthesized the structure and corroborate their formation by the PAGE technique. In addition, we have established the conditions to characterize their structural conformation change when they perform their sensor response. The sensing behavior was also accomplished by fluorescence spectroscopy techniques; FRET evaluation and fluorescence microscopy imaging. Providing the evidence about their adequate sensing performance outside and inside the cells detected in real-time.
In a preliminary evaluation we have tried to show the in vitro functionality of our structures in different cancer cell lines with the ability to perform local sensing responses. Our findings suggest that DNA sensor nanostructures could serve as a platform to exploit further therapeutic achievements in live cells.
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Shah, Ketan. "Development of clinical biomarkers of DNA double strand breaks for cancer care." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:2e6b2595-fbbc-4fff-80e2-bec8a4d9d15e.
Повний текст джерелаАнотація:
Many anticancer therapies, including radiotherapy, act by damaging the deoxyribosenucleic acid (DNA) that is fundamental to cell function and proliferation. H2AX is a histone protein associated with DNA that is phosphorylated to produce γH2AX in response to DNA double strand breaks (DSBs), the most lethal lesions caused in cancer cells. This thesis examines the translation of γH2AX detection assays to clinical situations in order to provide biomarkers of response that might help to guide the treatment of cancer patients. γH2AX immunohistochemistry was developed in preclinical xenograft models, and validated over a range of radiation doses and over time after irradiation. The method was prepared for translation to archived clinical biopsy and surgical specimens. The DSB Biomarkers Pilot Study was established in order to develop a method for γH2AX quantification in direct tumour cell specimens obtained using the clinical technique of fine needle aspiration (FNA) cytology. Eleven patients undergoing anticancer therapy were recruited to the study, and the method evaluated. The coefficient of variation of the measure was 49%. Non-invasive imaging for γH2AX would allow DNA damage to be quantified in all tumour sites, and on multiple occasions. An antibody-based nuclear medicine imaging agent was re-engineered using Fab fragments of the antibody. The novel agent demonstrated improved pharmacokinetics when compared to the whole antibody agent, but reduced target specificity. The findings further develop the potential to exploit DNA damage biomarker measurements in clinical oncology.
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Banerjee, Anusuya. "Novel, Targettable Bioimaging Probes Using Conjugates of Quantum Dots and DNA." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066376/document.
Повний текст джерелаАнотація:
Les boîtes quantiques (ou Quantum Dots en anglais - QD) sont une nouvelle génération de sondes polyvalentes pour la biologie, en particulier pour l’imagerie. Pour des applications de marquage des voies intra-cellulaires, les QDs peuvent être conjugués à des biomolécules telles que des acides nucléiques ou des protéines. En partant des travaux du LPEM portant sur le développement de ligands permettant la dispersion des QDs dans l’eau et leur fonctionnalisation, une nouvelle méthode de conjugaison de l'ADN sur les QDs a été développée dans cette thèse. Cette méthode utilise les motifs présents sur les polymères des QDs pour le greffage d'ADN. Les paramètres affectant cette réaction ont été étudiés et cette stratégie de couplage a été étendue à d'autres nanoparticules et biomolécules. En partant de ces QDs-ADN, des protéines modifiées ADN ont pu être attachées aux QDs en utilisant le principe d’hybridation de l’ADN. Les propriétés des conjugués ainsi générés ont été mises en évidence en utilisant la Transferrine (QD-ADN-Tf) et ces complexes ont été étudiés in vitro et in cellulo. Ces conjugués ont ensuite été utilisés pour le suivi de la dynamique des endosomes, exploitant ainsi pleinement le potentiel des QDs pour l’imagerie directe. Dans la dernière partie, des études supplémentaires sur les facteurs influençant la «performance biologique» des QDs ont été réalisées. Pour cela, une large gamme de ligands polymères développée par le groupe a été utilisée pour sonder l'interaction de la surface des QDs avec l'interface biologique. Des expériences biochimiques et cellulaires ont permis de démontrer que les QDs revêtus de divers polymères ont des comportements différentsQuantum dots (QD) are new generation of versatile probes for biology, particularly for bioimaging. For specific applications, QDs are conjugated to biomolecules such as nucleic acid or proteins and subsequently targeted to unique intra-cellular pathways. Building upon the state-of-the-art ligands for water-dispersible QDs developed by the lab, a novel and highly generalizable method to conjugate DNA to QD is developed in this thesis. This method employs thiols present on polymers on QDs for conjugation to maleimide-functionalized DNA. Extensive characterization of parameters affecting this reaction is carried out and the strategy is extended to other nanoparticles and biomolecules. Following this, a novel method to conjugate proteins to QD via DNA hybridization is discussed. Using a model protein Transferrin (Tf), the unique properties of thus generated QD-DNA-Tf conjugates are studied in-vitro and in-cellulo. These conjugates are subsequently used for tracking endosomal dynamics for up-to 20 minutes, exploiting the fullest potential of QDs for live imaging. In the last part, additional studies on factors affecting the ‘biological performance’ of QDs are carried out. Using a range of highly adaptable polymeric ligands developed by the group, interactions of surface-modified QDs with the biological interface are probed. Systematic biochemical and cellular experiments demonstrate that QDs coated with zwitterionic polymers have superior antifouling properties compared to poly(ethylene glycol)-based polymers and stability in diverse biological contexts
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Banerjee, Anusuya. "Novel, Targettable Bioimaging Probes Using Conjugates of Quantum Dots and DNA." Electronic Thesis or Diss., Paris 6, 2016. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2016PA066376.pdf.
Повний текст джерелаАнотація:
Les boîtes quantiques (ou Quantum Dots en anglais - QD) sont une nouvelle génération de sondes polyvalentes pour la biologie, en particulier pour l’imagerie. Pour des applications de marquage des voies intra-cellulaires, les QDs peuvent être conjugués à des biomolécules telles que des acides nucléiques ou des protéines. En partant des travaux du LPEM portant sur le développement de ligands permettant la dispersion des QDs dans l’eau et leur fonctionnalisation, une nouvelle méthode de conjugaison de l'ADN sur les QDs a été développée dans cette thèse. Cette méthode utilise les motifs présents sur les polymères des QDs pour le greffage d'ADN. Les paramètres affectant cette réaction ont été étudiés et cette stratégie de couplage a été étendue à d'autres nanoparticules et biomolécules. En partant de ces QDs-ADN, des protéines modifiées ADN ont pu être attachées aux QDs en utilisant le principe d’hybridation de l’ADN. Les propriétés des conjugués ainsi générés ont été mises en évidence en utilisant la Transferrine (QD-ADN-Tf) et ces complexes ont été étudiés in vitro et in cellulo. Ces conjugués ont ensuite été utilisés pour le suivi de la dynamique des endosomes, exploitant ainsi pleinement le potentiel des QDs pour l’imagerie directe. Dans la dernière partie, des études supplémentaires sur les facteurs influençant la «performance biologique» des QDs ont été réalisées. Pour cela, une large gamme de ligands polymères développée par le groupe a été utilisée pour sonder l'interaction de la surface des QDs avec l'interface biologique. Des expériences biochimiques et cellulaires ont permis de démontrer que les QDs revêtus de divers polymères ont des comportements différentsQuantum dots (QD) are new generation of versatile probes for biology, particularly for bioimaging. For specific applications, QDs are conjugated to biomolecules such as nucleic acid or proteins and subsequently targeted to unique intra-cellular pathways. Building upon the state-of-the-art ligands for water-dispersible QDs developed by the lab, a novel and highly generalizable method to conjugate DNA to QD is developed in this thesis. This method employs thiols present on polymers on QDs for conjugation to maleimide-functionalized DNA. Extensive characterization of parameters affecting this reaction is carried out and the strategy is extended to other nanoparticles and biomolecules. Following this, a novel method to conjugate proteins to QD via DNA hybridization is discussed. Using a model protein Transferrin (Tf), the unique properties of thus generated QD-DNA-Tf conjugates are studied in-vitro and in-cellulo. These conjugates are subsequently used for tracking endosomal dynamics for up-to 20 minutes, exploiting the fullest potential of QDs for live imaging. In the last part, additional studies on factors affecting the ‘biological performance’ of QDs are carried out. Using a range of highly adaptable polymeric ligands developed by the group, interactions of surface-modified QDs with the biological interface are probed. Systematic biochemical and cellular experiments demonstrate that QDs coated with zwitterionic polymers have superior antifouling properties compared to poly(ethylene glycol)-based polymers and stability in diverse biological contexts
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Cristofaro, Antonella Pia. "Imaging Diagnostico utilizzato in neuroradiologia per lo studio degli Aneurismi Cerebrali." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/9942/.
Повний текст джерелаАнотація:
Durante la mia tesi mi sono occupata di una grave patologia, l’Aneurisma Cerebrale, che rappresenta una delle principali cause di ospedalizzazione provocando il 10/12% della mortalità globale annua nei paesi industrializzati. In Italia , l’incidenza di aneurismi cerebrali è di 100.000 nuovi casi all’anno. In generale , nei paesi industrializzati, la prevalenza è stimata a circa 600 per 100.000 abitanti . Tuttavia la prevalenza degli aneurismi cerebrali nelle popolazioni in generale , è molto più elevato stimato intorno al 2,3%,il che suggerisce indirettamente che la maggior parte degli aneurismi non va mai incontro a rottura. Negli ultimi vent’anni lo sviluppo della tecnologia ha visto significativi progressi che ci hanno permesso di agire sul problema in modo sempre migliore. Nei primi capitoli ho descritto alcune apparecchiature biomediche che sono di fondamentale importanza nello studio degli aneurismi cerebrali, mettendo in evidenza le varie peculiarità che le contraddistinguono. A seguire, ho parlato del trattamento endovascolare, che consiste nell’esclusione della cavità aneurismatica dal flusso di sangue, il quale viene incanalato in una protesi posizionata all’interno del lume vasale eliminando il rischio di rottura o di embolizzazione di materiale trombotico proveniente dalla sacca aneurismatica.
I vantaggi della tecnica endovascolare consistono nella minore invasività rispetto alla tecnica chirurgica standard, la craniotomia.
A fronte di ciò, si deduce quanto l’ingegneria biomedica sia una disciplina in evoluzione. Le condizioni di vita delle persone che subiscono questi tipi di interventi sono notevolmente migliorate ottenendo risultati di completa o semi-completa guarigione.
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Bou, Sleiman Joyce. "Terahertz imaging and spectroscopy : application to defense and security." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0077/document.
Повний текст джерелаАнотація:
Le but de ce travail est de quantifier le potentiel et les capacités de la technologie térahertz à contrôler des colis afin de détecter les menaces telles que les armes et les explosifs, sans avoir besoin d'ouvrir le colis.Dans cette étude, nous présentons la spectroscopie térahertz résolue en temps et l'imagerie multi-spectrale pour la détection des explosifs. Deux types d’explosifs, ainsi que leurs mélanges binaires sont analysés. En raison de la complexité de l'extraction des informations face à tels échantillons, trois outils de chimiométrie sont utilisés: l’analyse en composantes principales (ACP), l'analyse des moindres carrés partiels (PLS) et l'analyse des moindres carrés partiels discriminante (PLS-DA). Les méthodes sont appliquées sur des données spectrales térahertz et sur des images spectrales pour : (i) décrire un ensemble de données inconnues et identifier des similitudes entre les échantillons par l'ACP ; (ii) créer des classes, ensuite classer les échantillons inconnus par PLS-DA ; (iii) créer un modèle capable de prédire les concentrations d’un explosif, à l'état pur ou dans des mélanges, par PLS.Dans la deuxième partie de ce travail, nous présentons l'imagerie par les ondes millimétriques pour la détection d'armes dans les colis. Trois techniques d'imagerie différentes sont étudiées : l'imagerie passive, l’imagerie active par des ondes continues (CW) et l’imagerie active par modulation de fréquence (FMCW). Les performances, les avantages et les limitations de chacune de ces techniques, pour l’inspection de colis, sont présentés. En outre, la technique de reconstruction tomographique est appliquée à chacune de ces trois techniques, pour visualiser en 3D et inspecter les colis en volume. Dans cet ordre, un algorithme de tomographie spécial est développé en prenant en considération la propagation gaussienne de l'ondeThe aim of this work is to demonstrate the potential and capabilities of terahertz technology for parcels screening and inspection to detect threats such as weapons and explosives, without the need to open the parcel.In this study, we first present terahertz time-domain spectroscopy and spectral imaging for explosives detection. Two types of explosives as well as their binary mixture is analyzed. Due to the complexity of extracting information when facing such mixtures of samples, three chemometric tools are used: principal component analysis (PCA), partial least square analysis (PLS) and partial least squares-discriminant analysis (PLS-DA). The analyses are applied to terahertz spectral data and to spectral-images in order to: (i) describe a set of unknown data and identify similarities between samples by PCA; (ii) create a classification model and predict the belonging of unknown samples to each of the classes, by PLS-DA; (iii) create a model able to quantify and predict the explosive concentrations in a pure state or in mixtures, by PLS.The second part of this work focuses on millimeter wave imaging for weapon detection in parcels. Three different imaging techniques are studied: passive imaging, continuous wave (CW) active imaging and frequency modulated continuous wave (FMCW) active imaging. The performances, the advantages and the limitations of each of the three techniques, for parcel inspection, are exhibited. Moreover, computed tomography is applied to each of the three techniques to visualize data in 3D and inspect parcels in volume. Thus, a special tomography algorithm is developed by taking in consideration the Gaussian propagation of the wave
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Ferreira, Carlos André Marques Viana. "Handling data access latency in distributed medical imaging environments." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15491.
Повний текст джерелаАнотація:
Doutoramento em Ciências da ComputaçãoWeb-based technologies have been increasingly used in Picture Archive and Communication Systems (PACS), in services related to storage, distribution and visualization of medical images. Nowadays, many healthcare institutions are federating services and outsourcing their repositories to the Cloud. However, managing communications between multiple geo-distributed locations is still challenging due to the complexity of dealing with huge volumes of data and bandwidth limitations. Communication latency is a critical issue that still hinders the adoption of this paradigm. In order to improve the performance of distributed medical imaging networks, routing mechanisms with cache and prefetching can be used. This doctorate proposes a cache architecture based on static rules together with pattern recognition for both cache eviction and prefetching.
As tecnologias Web têm sido usadas cada vez mais no universo dos Picture Archiving and Communication Systems (PACS), nomeadamente em serviços de armazenamento, distribuição e visualização de imagem médica. Atualmente, verificamos que existe uma tendências para as instituições partilharem fluxos de trabalho e contratualizarem serviços na Cloud. No entanto, gerir as comunicações entre entidades geograficamente distribuídas continua a ser um desafio complexo devido ao enorme volume de dados e às limitações de largura de banda. A latência de acesso remoto aos dados é um problema importante que dificulta a adopção deste paradigma. Para melhorar o desempenho de redes distribuídas de imagem médica, podemos utilizar mecanismos de encaminhamento com cache e prefetching. Este doutoramento propõe uma arquitetura de cache baseada em regras estáticas e reconhecimento de padrões para prefetching e limpeza da cache.
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Ahedi, HK. "Assessment of hip structure and musculature using MRI and DXA images from TASOAC cohort." Thesis, 2016. https://eprints.utas.edu.au/23411/1/Ahedi_whole_thesis_ex_pub_mat.pdf.
Повний текст джерелаАнотація:
Introduction
Osteoarthritis (OA) is a multifactorial musculoskeletal disorder and its aetiology is under investigation. Current research and therapeutic interventions for hip OA are limited. In early or advanced stages of hip OA, imaging techniques can be used to scrutinize overall structural and muscular changes in the joint such as bone marrow lesions (BMLs), hip cartilage defects, hip effusion-synovitis, bone shape and muscle health. Investigating these factors can provide information on interactive pathways vital for understanding the aetiology of OA. This thesis reports the results of six such investigations.
Materials and Methods
The Tasmanian Older Adult Cohort (TASOAC) is a large population based cohort study initiated in 2002. Older adults aged 50-80 years (51% female, mean age 62yrs) were enrolled into the study at baseline (Phase 1) with a first follow-up approximately 3 years later (Phase 2), a second follow up (Phase 3) approximately 5 years from baseline and a third follow up (Phase 4) approximately 10 years from baseline. Hip and knee pain was assessed using the WOMAC (Western Ontario and McMaster Universities Osteoarthritis). Pedometers and a dynamometer were used to measure physical activity and muscle strength respectively. Hip structural abnormalities and hip muscle cross-sectional area (CSA) were assessed from MRI scans. Bone mineral density (BMD) was estimated by dual-energy x-ray absorptiometry (DXA). Morphological shape of the hip was assessed by Active Shape Modelling (ASM) imaging software and radiographic hip OA (ROA) was determined from X-rays.
Results
The first two studies focus on hip BMLs and their cross-sectional and longitudinal associations with hip and knee pain, high cartilage signal and BMD. Overall, the proportion of hip BMLs at the femoral and/or acetabular site was 28%. About 8% of the population had a large hip BML. In the first study, those with large hip BMLs had greater hip pain. Incidence of larger hip BMLs (femoral and acetabular) was associated with an increase in hip pain. On the other hand, resolution of femoral BMLs was associated with a decrease in knee pain. Additionally, 1 S.D increase in hip BML size was associated with worsening hip pain. High cartilage signal intensity was strongly associated with hip BMLs but not with hip pain. This study identified that hip BMLs associate not only with hip and knee pain but also with early changes in the hip cartilage. In the second study, irrespective of size, hip BMLs were found to be associated with local (total hip and femoral neck) BMD but not with distant (spine) BMD. Femoral BMLs were associated with higher femoral neck BMD while acetabular BMLs were associated with lower hip and femoral neck BMD. This novel study suggests that hip BMLs located in two different compartments might represent bone areas undergoing different pathological changes.
In the third study, correlates of hip cartilage defects were examined. About 76% of the subjects had a hip cartilage defect. Any and grade 2 hip cartilage defects were associated with higher prevalence of hip pain. Any hip cartilage defects associated with lower muscle strength, particularly among men. The associations of grade 1 defect with high cartilage signal were stronger for men than for women. However, associations between grade 1 defects and BMLs were equivalent in both sexes. Grade 2 defects were linked with several outcomes such as hip BML, larger hip effusion-synovitis and hip ROA (in men), and lower steps per day. This study indicates that cartilage defects/damage, especially grade 2 hip cartilage defects are associated with major clinical and structural risk factors relevant to hip OA even in the general population.
The fourth study describes the cross-sectional and longitudinal correlates of hip effusion-synovitis. Cross-sectionally, presence of hip effusion-synovitis at multiple sites was associated with presence of hip pain, and hip cartilage defects were associated with greater hip effusion-synovitis CSA. No other associations were found. Longitudinally, independently of each other, persistent hip BMLs and incident hip cartilage defects predicted larger hip effusion-synovitis size. However, change in hip pain from baseline to follow up and baseline hip ROA were not associated with hip effusion-synovitis. Additionally, baseline hip cartilage defects were associated with worsening hip BMLs at follow up. Similarly, baseline hip BMLs were associated with hip cartilage defects at follow-up. Overall, these results suggest that hip cartilage defects, hip BMLs and hip effusion-synovitis share possible causal pathways and the extent of hip effusion-synovitis might influence hip pain. The fifth study explored the link between hip musculature (hip muscle CSA), muscle strength and bone mass (BMD). Among older adults, hip flexor CSA had the strongest association with BMD of the hip. The associations for pectineus and sartorius hip muscles CSA with BMD were stronger for women in comparison to men. Most of hip muscles CSA were associated with muscle strength and muscle strength was weakly associated with BMD. These findings suggest that for older adults, muscle bulk contributes to hip bone mass more so than muscle strength and maintaining muscle mass would aid in preservation of bone health.
The sixth and the final study focused on hip morphology (shape) and its associations with various outcomes. Using Active shape modelling (ASM) imaging software and SHAPE software, hip shape was assessed and the first six principal components (modes) describing the variations in measurements of hip shape were extracted. These modes explained 68% of total hip shape variations in the sample population. At baseline, modes 1, 2, 4 and 6 were associated with hip ROA, modes 1, 3, 4 and 6 correlated with hip cartilage volume and all except mode 2 with muscle strength. Higher mode 1, and lower mode 3 and 6 scores at baseline predicted greater hip pain at follow-up and higher mode 1 and mode 2 scores were associated with hip effusion-synovitis. Greater scores for modes 2 (decreasing acetabular coverage) and 4 (non-spherical femoral head) at baseline predicted 10-year total hip replacement (THR); while mode 4 alone correlated with bone marrow lesions (BMLs), effusion-synovitis, and increased cartilage signal.
Conclusions
Overall, structural changes are slow and relatively uncommon in the preclinical stages of hip OA. Nevertheless, hip BMLs, hip cartilage defects, high cartilage signal and hip effusion-synovitis are inter-related and contribute to changes in the subchondral bone; with a probable role in the pathogenesis of hip OA. Additionally, muscle bulk and strength could aid in preservation of bone density and assessing bone shape using ASM could benefit in improving assessment and monitoring of disease progression and identifying those at higher risk of OA.
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Hsu, Kevin, and 徐中文. "Imaging DNA Using Scanning Tunneling Microscopy." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/06527233112602635889.
Повний текст джерелаАнотація:
碩士東海大學
物理學系
94
Since the Scanning Tunneling Microscopy (STM) can achieve atomic-scale resolution in imaging, it has been used to study surface nanostructures of various materials. In order to image DNA with STM, a protocol of preparing DNA immobilized on annealed gold foil has been developed. Using STM in air, clear image of DNA has been obtained. Moreover, DNA in de-ionized water can also be imaged by using tungsten tip coated with nail polish. These progresses can shed light on further studies in the molecular biology.
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Sung, Yi-Ying, and 宋易穎. "Estimation of DNA Contour Tangential with Atomic Force Microscopy Imaging." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/59ashb.
Повний текст джерелаАнотація:
碩士國立臺灣科技大學
機械工程系
105
Atomic Force Microscopy (AFM) captures nano-scale resolution biopolymers with relative ease, and has been applied to image string-like biopolymer samples , such as deoxyribonucleic acid (DNA). In order to make the calculation of DNA Geometric characteristics such as contour length and Persistence Length , there are many researches devoted to acquiring clearer AFM image of DNA. Contour length refers to the length of the DNA shape , and there are some error when calculating in different image resolutions. In the previous study, there are many researcher have proposed different algorithms to estimate , and different algorithms have different ways to revise the accuracy. The previous study of this paper was analyze the 8-connected Freeman chain codes, to design a estimater for estimating contours length in different pixel resolutions. We do a series of image processing for the DNA image after that we thining binary image into single pixel width , and analysing the single width images pixel , then sort out the shape numbers and use the shape numbers to revise the estimating result.The persistence length represents the rigidity of the DNA molecular chain and can predict the bending of the DNA. in order to have accurate estimattion in persistence length , we need the accurate contour length and the contour tangent . Therefore, we will study the DNA contour tangent estimation method.
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Hsiao, Ming-Chih, and 蕭名智. "DNA Contour Length Estimator utilizing Shape Number from AFM Imaging." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/ddh3w2.
Повний текст джерелаАнотація:
碩士國立臺灣科技大學
機械工程系
104
This thesis simulates on DNA images acquired from AFM experiments, and proposes a method estimating DNA contour length based on digitized DNA images encoded by chain code and shape number after its image thinning operation. The error in calculating DNA length comes mostly from digitization of line segments with different curvature under various resolution. As a result, this thesis discusses the calculation of DNA contour length with a focus on different pixel resolution images. We apply a two-dimensional worm-like chain model of DNA to produce a large number of simulated AFM images with different resolutions, and according to different resolutions we calculate the coefficients of our designed length estimator. Finally, we developed a length estimator which is precise, rapid, and applicable to any resolution of AFM image using different coefficients.
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YU, I.-Jui, and 余奕叡. "Estimation of DNA Persistence Length with Atomic Force Microscopy Imaging." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/zg5yzm.
Повний текст джерелаАнотація:
碩士國立臺灣科技大學
機械工程系
107
In this paper, the persistence length is estimated by DNA digital image, and the digital image of the cross sample can be estimated. In the past, scholars did not discuss overlapping DNA samples in the study of DNA imaging estimation. The persistence Length is the stiffness of the polymer. Accurate estimation of the length of the DNA curve contour and the contour cut vector are required in calculating the long-lasting length. In estimating the contour cut vector, using the DNA image captured by AFM, there is an error in calculating the contour cut vector at different image resolutions. In the past, the median filter difference method was used to correct the estimation. In this study, the median fitting ordering method was proposed to correct the estimation. The difference between the two is mainly that the median filtering difference method is mainly for all the tangent vectors in the average DNA segment, and the median fitting ordering method is to take the median of all the tangent vectors in the DNA segment. In this study, the two methods are also used as the tangent vector angle estimator. In addition to adding the self-crossing image, the "automatic cross-direction judgment algorithm" is used to incorporate the cross-image into the research sample for the first time, and the Ferryman chain code is used. In this paper, the four-pixel length estimator is used to estimate the contour length, and the two contour cut vector estimators just mentioned are added to estimate the contour cut vector, and then the longest length of each is estimated, and the two are Conduct a comparative discussion.
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Hards, Andrew [Verfasser]. "The combined AFM manipulation and fluorescence imaging of single DNA molecules / Andrew Hards." 2004. http://d-nb.info/972305750/34.
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Thomas, Brigette N. "Portrait/icon/code Marc Quinn's DNA portraits and the imaging of the self /." 2009. http://purl.galileo.usg.edu/uga%5Fetd/thomas%5Fbrigette%5Fn%5F200905%5Fma.
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Amorim, João Pedro Curado Agra. "Imaging Telomeres by CRISPR/CAS9." Dissertação, 2016. https://repositorio-aberto.up.pt/handle/10216/87747.
Повний текст джерела