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Articles 1 - 30 of 45
Full-Text Articles in Physics
Identification Of Nanotechnology Skill Shortages In Ireland’S Agri-Food Sector: Towards The Safe, Innovative And Sustainable Development Of Nano-Food Technology, Eileen Mccarron
Doctoral
The purpose of this research was to assess the nanotechnology skill and capacity shortages in Irelands Agri-food sector. In 2008 the Food Safety Authority of Ireland (FSAI) published its statement on ‘The Relevance for Food Safety of Applications of Nanotechnology in the Food and Feed Industries’. The importance of the food sector to the Irish economy was clearly emphasised by the FSAI’s statement. The report identified the urgent need for focused research programs into the potential of nanotechnology in the agri-food sector and it highlighted the need for a multi-organisation approach between state agencies, industry and academia to ensure safe …
Development Of 3d In Vitro Tissue Models For The Analysis Of Solar Radiation Damage Of Skin, Ulises Lopez Gonzalez
Development Of 3d In Vitro Tissue Models For The Analysis Of Solar Radiation Damage Of Skin, Ulises Lopez Gonzalez
Doctoral
The aim of this work was to investigate changes to the molecular composition and conformation of HaCaT cells as a result of simulated solar radiation in a 3D in vitro skin model by Raman spectroscopy. The process to achieve this goal was performed in three main stages: (1) optimisation of the working concentration and volume of two 3D membranes, used as a structural support in the skin model; (2) the construction of the 3D in vitro skin model and; (3) the investigation of the dose-dependent effects of solar radiation on HaCaT cells in the skin model in comparison with the …
Big Data: Potential As An Ocular Epidemiology And Public Health Tool, Michael Moore
Big Data: Potential As An Ocular Epidemiology And Public Health Tool, Michael Moore
Doctoral
Refractive error is a significant cause of vision impairment both through the limited access to correction in some areas and the associated ocular diseases for which refractive errors are risk factors. Having timely, regular access to population level estimates of refractive error and vision impairment is necessary to adequately plan public health resources and resource appropriate interventions. A lack of access to current and regularly updated refractive error and vision impairment prevalence data has been identified as a significant limitation in predicting future population trends with many countries lacking any prevalence data or available data being outdated. This project addresses …
Liposomal Encapsulation Of Silver Nanoparticles To Enhance Nanoparticle Cytotoxicity And Modulate Induced Inflammatory Responses In Vitro, Azeez Yusuf
Doctoral
High concentrations of silver nanoparticles (AgNP) are increasingly present as active ingredient in everyday consumable products for antibacterial purposes causing increased human exposure and high risk of adverse effect development. In this thesis, AgNP were encapsulated in dipalmitoyl phosphatidylcholine (DPPC)-based liposome (forming Lipo-AgNP), to enhance intracellular delivery and associated cytotoxicity, and suppress AgNP-induced inflammation. It was noted that as a result of the encapsulation, Lipo-AgNP induced significantly reduced cell viability of THP1 monocytes and THP1 differentiated macrophages (TDM) at a notably lower dose than that of uncoated AgNP. The induced cytotoxicity was shown to result in an increased level of …
Multivariate Statistical Methodologies Used In In-Vitro Raman Spectroscopy: Simulations And Applications For Drug And Nanoparticle Interactions, Mark Edward Keating
Multivariate Statistical Methodologies Used In In-Vitro Raman Spectroscopy: Simulations And Applications For Drug And Nanoparticle Interactions, Mark Edward Keating
Doctoral
Raman spectroscopy is a growing technology in the fields of in-vitro drug and nanoparticle screening. The label free capability provided by vibrational spectroscopy, as well as the ability of the technique to probe the chemical nature of samples, makes it a good candidate for use in these fields. Crucial to the progress of these methods is the development and validation of robust and accurate multivariate statistical analysis protocols. In this thesis, both established and novel methods are examined using both real and simulated datasets. In particular, simulated datasets are used to validate and assess the accuracy of these methods in …
Fluid-Dynamic Models Of Geophysical Waves, Alan Compelli
Fluid-Dynamic Models Of Geophysical Waves, Alan Compelli
Doctoral
Geophysical waves are waves that are found naturally in the Earth's atmosphere and oceans. Internal waves, that is waves that act as an interface between uids of dierent density, are examples of geophysical waves. A uid system with a at bottom, at surface and internal wave is initially considered. The system has a depth-dependent current which mimics a typical ocean set-up and, as it is based on the surface of the rotating Earth, incorporates Coriolis forces. Using well established uid dynamic techniques, the total energy is calculated and used to determine the dynamics of the system using a procedure called …
The Potential Of Raman Spectroscopy In The Diagnosis Of Premalignant Oral Lesions, Ola Ibrahim
The Potential Of Raman Spectroscopy In The Diagnosis Of Premalignant Oral Lesions, Ola Ibrahim
Doctoral
Thesis submitted in partial fulfilment for the degree of Doctor of Philosophy (PhD) Technological University Dublin, School of Physics December 2017.
Advancing Vibrational Spectroscopy For Cellular And Sub Cellular Analysis: Raman Spectroscopy As An In Vitro Chemotherapeutic Screeening And Assessment Protocol, Zeineb Farhane
Doctoral
Vibrational spectroscopy, including Raman micro-spectroscopy, has attracted considerable attention over the last few years, as a powerful, non-invasive tool for clinical applications, especially in cancer diagnosis, in vivo and ex vivo. As a molecular fingerprinting technique with optical resolution, Raman micro-spectroscopy is able to monitor biochemical processes, drug uptake, efficacy and mode of action and mechanisms of interaction of chemotherapeutic drugs at a subcellular level. In vitro applications may be more strategically achievable, and can help guide drug design and discovery, and eventually evaluate To this end, different lung cell lines were used and Raman micro-spectroscopy was coupled to valuable …
Advancing Vibrational Spectroscopy For Cellular And Sub Cellular Analysis: Raman Spectroscopy As A Novel In Vitro Nanotoxicological Assessment Protocol, Esen Efeoglu
Doctoral
This work is designed to establish a ‘High content Nanotoxicological Screening method’ using in vitro Raman microspectroscopy. The undeniable increase of nanotechnology based products has brought challenges in terms of determining their toxicological properties. Considering the total time and cost of screening nanomaterials by conventional methods, the need for a rapid, label-free technique which will provide a wide range of information on multiple parameters is unquestionable. This study investigated the applicability of Raman microspectroscopy as a High Content Screening technique to clarify cell-nanoparticle interaction by determining the localisation of the nanoparticles and consequent effects in these localised areas in terms …
Investigation Of Photopolymer-Based Holographic Optical Elements For Solar Applications, Hoda Akbari
Investigation Of Photopolymer-Based Holographic Optical Elements For Solar Applications, Hoda Akbari
Doctoral
The aim of this research was to explore the potential of photopolymer Holographic Optical Elements (HOE) for use in the collection of light from a moving source, such as the sun, and its direction into a fixed detector/convertor for application in solar concentrators. In order to increase the acceptance angle and the wavelength range of operation of the holographic device, low spatial frequency holographic recording was explored. The challenge was to record high diffraction efficiency HOEs at this spatial frequency, since it requires a material with relatively fast monomer diffusion. The acrylamide-based photopolymer developed at the Centre for Industrial and …
Refraction In Mozambique: Evaluations Of Practice And Development Of Competency Frameworks For Eye Care Personnel, Kajal Shah
Doctoral
Purpose The development of competency- based education for optometrists and mid-level eye-care personnel has been identified as an important component in the elimination of avoidable blindness and vision impairment. The Mozambique Eye care Project (MEP) is a multi-institutional collaboration, which seeks to facilitate greater access to training in eye health professions, which will ultimately contribute to providing affordable and accessible eye care within the public health system in Mozambique. An important tenet of the MEP is to develop and enhance the refraction training of all existing (ophthalmic technicians) and new eye care personnel (four-year training of optometrists and eighteen-month training …
What Is Nanoscience?' - A Hermeneutic Phenomenological Study Of Nanoscience Researchers' Experiences, Deepa Chari
What Is Nanoscience?' - A Hermeneutic Phenomenological Study Of Nanoscience Researchers' Experiences, Deepa Chari
Doctoral
Nanoscience and nanotechnology have been described as a research area that integrates many scientific and engineering disciplines. However, the integration of disciplines is so complex that the disciplinarity of nanoscience and nanotechnology remains undefined. As a result, the nanoscience and nanotechnology area is viewed as multidisciplinary, or interdisciplinary science, or even as a separate discipline and there is no consensus regarding its disciplinarity. The previous studies conducted in order to describe the disciplinarity associated with this area have focused mainly on political, institutional and external factors while the cognitive aspects of disciplinarity of nanoscience and nanotechnology are still less understood. …
The Social And Economic Impact Of Refractive Error In Mozambique, Stephen James Thompson
The Social And Economic Impact Of Refractive Error In Mozambique, Stephen James Thompson
Doctoral
The purpose of this thesis is to investigate potential key determinants of the success, or otherwise, of endeavours to address avoidable Visual Impairment (VI) by addressing Uncorrected Refractive Error (URE) in Mozambique and the wider region of sub-Saharan Africa by providing optometric services. It includes a Cost Benefit Analysis (CBA) of a higher education optometry training programme, barriers that might prevent the realisation of overarching goals despite a successful training programme, and a Willingness to Pay (WTP) analysis to inform the pricing structure and to determine the financial sustainability of the system. Methods A standard CBA methodology was applied to …
Low-Toxicity Diacetone Acrylamide-Based Photopolymer For Applications In Holography, Dervil Cody
Low-Toxicity Diacetone Acrylamide-Based Photopolymer For Applications In Holography, Dervil Cody
Doctoral
Photopolymers are fast becoming one of the most popular holographic recording media due to their suitability for a wide range of holographic applications, such as sensors, diffractive optics and data storage. The majority of the investigated water-soluble holographic photopolymers are Acrylamide (AA) based. However, the toxic and carcinogenic nature of AA is a growing concern. In order for photopolymer recording media to be a viable option for holographic applications, efforts must be made to remove any occupational and environmental hazards involved in large-scale material development and device fabrication. The main objective of the work presented here is the development and …
Studies Of Shrinkage In Photopolymerisable Materials For Holographic Applications, Mohesh Moothanchery
Studies Of Shrinkage In Photopolymerisable Materials For Holographic Applications, Mohesh Moothanchery
Doctoral
Holography is now firmly established as a tool for scientific and engineering studies and also as a display medium. Holographic performance mainly depends on the choice of recording wavelengths, recording material, recording conditions and experimental setup as well as environmental conditions in the laboratory. Acrylamide based photopolymer has significant advantages as a holographic recording material such as self-development, low scatter, high diffraction efficiency, ease of preparation and low cost. The main objective of this project is to determine and minimise the shrinkage of an acrylamide based photopolymer developed in the Centre for Industrial and Engineering Optics for holographic recording. This …
The Role Of Colour Duplex Ultrasound In The Surveillance Of Patients Undergoing Endovascular Aneurysm Repair, Cleona Gray
The Role Of Colour Duplex Ultrasound In The Surveillance Of Patients Undergoing Endovascular Aneurysm Repair, Cleona Gray
Doctoral
No abstract provided.
Calculation Of The Electronic And Optical Properties Of Nanoscale Systems, Barry Haycock
Calculation Of The Electronic And Optical Properties Of Nanoscale Systems, Barry Haycock
Doctoral
At the nanometer length scale, the size of surface features in crystalline semiconductor systems is of the same order as the electron wavelength. This can result in unusual behaviour in the systems electronic, magnetic and optical properties due to electron confinement effects. Such effects can have practical and commercial applications and are currently the subject of considerable study in the disciplines of theoretical, computational and materials technology within nanoscience. This thesis uses molecular dynamics computational methods to examine such effects in the electronic structure of semiconductor-based crystalline systems. Three unique surfaces were studied in detail - the SiC(111) surface, the …
Interactions Of Carbon Nanotubes With Human Lung Epithelial Cells In Vitro, Assessed By Raman Spectroscopy, Peter Knief
Interactions Of Carbon Nanotubes With Human Lung Epithelial Cells In Vitro, Assessed By Raman Spectroscopy, Peter Knief
Doctoral
Current methods for the evaluation of cellular interactions with nanoparticles are non-specific, relatively slow and invasive to the cell. Raman spectroscopy is a non invasive technique whose potential in the biosciences has already been demonstrated and has been used in the investigation of cell interactions with various external agents. The main focus of this study is to employ Raman spectroscopy to investigate the interaction of A549 human lung cells with single walled carbon nanotubes. · Carbon nanotubes have attracted considerable interest not only for their outstanding physical and electronic properties, promising a potentially vast number of applications, but also for …
Development Of Acrylamide Based Photopolymer For Full Colour Display Holography, Chakrapani Meka
Development Of Acrylamide Based Photopolymer For Full Colour Display Holography, Chakrapani Meka
Doctoral
Holography is a firmly established discipline that can be used as a tool for scientific and engineering studies and as a display medium as well. Until now both silver halide photographic emulsions (SHPE) and dichromated gelatine (DCG) have been the most common materials used for high efficiency full colour reflection hologram recording. However, these materials require wet chemical processing for developing the holograms which is laborious and costly from the point of view of commercial applications. Self-developing photopolymers such as acrylamide based photopolymer (ABP) which do not require development are the ideal choice for real-time recording and reconstruction of holograms. …
Dispersion Of Single-Walled Carbon Nanotubes In Organic Solvents, Qiaohuan Cheng
Dispersion Of Single-Walled Carbon Nanotubes In Organic Solvents, Qiaohuan Cheng
Doctoral
This thesis contains a systematic study of the dispersion of pristine HiPco Single Walled Carbon Nanotubes (SWNTs) in a series of organic solvents. A double beamed UV-Vis-NIR absorption spectrometer coupled with an integrating sphere was employed to demonstrate the dispersibility of SWNTs in different solvents. Raman Spectroscopy and Atomic Force Microscopy (AFM) were used to confirm the debundling and exfoliation of SWNTs aggregates. An investigation of the solubility of SWNTs in four chlorinated aromatic solvents demonstrated that the similarity in structure between solvent molecules and nanotube sidewall is not a dominant factor to obtain stable SWNT solutions. A comparative study …
A Phenomenographic Study Of Introductory Physics Students: Approaches To Their Learning And Perceptions Of Their Learning Environment In A Physics Problem-Based Learning Environment, Paul Irving
Doctoral
This phenomenographic study describes students’ approaches to learning and their perceptions of the learning environment in an introductory physics course which is taught using a problem-based learning approach. This research builds on previous studies which showed that these students develop a greater conceptual knowledge than their counterparts in a more traditional learning environment while others showed very little development even though they engaged fully with the pedagogy. This study aimed to examine and describe the students’ approaches to learning. The definitions of surface, strategic and deep approaches to learning are not appropriate in this context and could not be applied …
Photopolymerizable Nanocomposites For Holographic Applications, Elsa Leite
Photopolymerizable Nanocomposites For Holographic Applications, Elsa Leite
Doctoral
Photopolymerizable nanocomposites with good optical properties consisting of an acrylamide based photopolymer and zeolite nanoparticles (Beta, zeolite A, AlPO-18, silicalite-1 and zeolite L) were fabricated and characterized for holographic applications. The colloidal zeolite solutions used in this project were characterized by several techniques including X-Ray Diffraction (XRD), Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM) and Raman spectroscopy to ensure their successful synthesis. The dependence of grating performances in these nanocomposites on recording intensity, spatial frequency and zeolite concentration were studied. It was found that the incorporation of silicalite-1 nanoparticles or a small amount of zeolite A nanoparticles (up to …
Metal-Induced Bystander Effects: Mechanism And Implicationis., Nicola Cogan
Metal-Induced Bystander Effects: Mechanism And Implicationis., Nicola Cogan
Doctoral
The radiation-induced bystander effect is a phenomenon known to occur post irradiation, characterised by the induction of biological effects in unirradiated cells as a result of receiving signals from irradiated cells or their culture medium. Chemicalinduced bystander effects are poorly characterised and there are no reports of a bystander effect induced by metals. Heavy metals and in particular chromium (VI) are known to cause persistent genomic instability. For the first time, this study provides evidence that a short, low-dose exposure of human fibroblasts to chromium (VI) causes a bystander effect in human fibroblasts that persists for at least thirty days …
Development Of Renal Phantoms For The Evaluation Of Current And Emerging Ultrasound Technology, Deirdre King
Development Of Renal Phantoms For The Evaluation Of Current And Emerging Ultrasound Technology, Deirdre King
Doctoral
The primary aim of this project was to develop novel anatomically realistic renal phantoms for the evaluation of current and emerging ultrasound techniques capable of diagnosing all grades of renal artery stenosis. Renal artery stenosis is considered the most common cause of potentially curable secondary hypertension which if left untreated can lead to renal failure. Its early detection is very important as it offers the possibility of various drug treatments, which are considerably less invasive and poses less risk to the patient. Computer-aided modelling techniques were used to generate a range of anatomically realistic phantoms of the renal artery from …
Development And Evaluation Of A Novel Automated Physchophysical Instrument For The Investigation Of Nyctalopia Using Multiple Stimulus Light Emitting Diode Matrix Display Arrays., David M.C. O'Brien
Development And Evaluation Of A Novel Automated Physchophysical Instrument For The Investigation Of Nyctalopia Using Multiple Stimulus Light Emitting Diode Matrix Display Arrays., David M.C. O'Brien
Doctoral
Vitamin A deficiency primarily affects young children in developing countries, the symptoms of which initially present as nyctalopia, an inability of the eyes of ‘see’ in low luminance levels, specifically at twilight or at night. Vitamin A deficiency is a major cause of blindness in developing countries and is associated with significant increases in child morbidity and mortality. Nyctalopia may be examined using dark adaptometry; however, current methods of dark adaptometry have many practical limitations, including their unsuitability for use with children. This thesis reports on the design, construction, testing and evaluation of a novel automated dark adaptometer for use …
The Use Of Raman Spectroscopy In The Characterization Of Single Walled Carbon Nanotubes, Elizabeth Gregan
The Use Of Raman Spectroscopy In The Characterization Of Single Walled Carbon Nanotubes, Elizabeth Gregan
Doctoral
Carbon nanotubes, long, thin cylinders of carbon are intriguing structures and
have sparked much excitement in recent years. It is clear that understanding the fundamental properties of nanotubes is necessary to get a realisation of the full potential of these materials. Processing and purification on a mass scale will need to be carried out if these materials are to have large scale industrial applications and move beyond the laboratory bench. Highly sensitive, capital intensive equipment such as TEM and AFM, have been used to identify the state and morphology of tube samples as well as their levels of purity, however …
A Phenomenographic Study Of Introductory Physics Students: Approaches To Problem Solving And Conceptualisation Of Knowledge., Laura Walsh
Doctoral
This phenomenographic study presents a description of the approaches to problem solving and conceptualisation of physics knowledge of introductory physics students, specifically in the context of the Irish higher education system. Much research has been carried out that has shown that physics students are not developing the conceptual knowledge necessary to become adept problem-solvers. This may be due to the traditional physics education assumption that students will develop an understanding of the conceptual nature of physics by repetitively solving quantitative problems. However, research has shown that this is not the case and that education and the curriculum needs to explicitly …
Holographic Liquid Crystal Devices, Kotakonda Pavani
Holographic Liquid Crystal Devices, Kotakonda Pavani
Doctoral
Liquid crystals have become natural candidates for use in electro-optic devices for their ability to change the orientation of the director with the application of an electric field, and exhibiting large range of refractive index. The aim of the work presented in this thesis is to fabricate liquid crystal optoelectronic devices such as electrically switchable liquid crystal diffraction gratings and polarization rotators by exploiting the holographic surface relief effect in photopolymer and by developing novel polymer dispersed liquid crystals (PDLCs). Alignment of liquid crystals is commercially achieved by creating grooves on a conducting layer such as polyimide or indium tin …
Quantitative Analyses Of Dispersion, Doping And Electronic Separation Of Single Wall Hipco Carbon Nanotubes, Priya Baskar Rao
Quantitative Analyses Of Dispersion, Doping And Electronic Separation Of Single Wall Hipco Carbon Nanotubes, Priya Baskar Rao
Doctoral
As prepared SWNTs are obtained in bundles with a mixture of both metallic and semi conducting tubes. For many specific applications, electronically separated single individual tubes are required and in order to reach these application criteria, the tubes should be processed. This thesis reports on a systematic exploration of methods to routinely process, electronically separate and characterise commercially available single walled carbon nanotubes (SWNTs). Commercially available HiPco SWNTs were dispersed in water with the assistance of 1 % by weight sodium dodecyl benzene sulphate (SDBS). The tubes were dispersed in the water surfactant system through the aid of sonication and …
Toxicity Assessment Of Single-Walled Carbon Nanotubes, Eva Herzog
Toxicity Assessment Of Single-Walled Carbon Nanotubes, Eva Herzog
Doctoral
The objective of this study was to investigate the potential adverse health effects of occupational exposure to SWCNT dust using various in vitro approaches. Lung epithelium (represented by A549 and NHBE cells) was chosen as target cell model and exposed to minimally processed particle samples under submerse conditions and effects were compared to that of carbon black and crocidolite asbestos exposure. Cytotoxicity studies indicated low acute cytotoxicity of SWCNT. Morphological changes included decreases in microvilli and increased numbers of surfactant storing lamellar bodies and changes in cytoskeleton. Due to interactions of SWCNT and toxicity indicator dyes, the clonogenic assay was …