Digital watermarking and novel security devices

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Quantum enhanced optical measurements

L'abstract è presente nell'allegato / the abstract is in the attachmen

The materials, technique, conservation treatment and after-care of interior de um convento

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Conservação e Restauro, especialização em pintura sobre telaThis thesis concerns the study of the materials and techniques of the painting on canvas “Interior de um Convento” belonging to the Portuguese monument Pena National Palace (PNP) and the description of the conservation treatment carried out. The study required the use of several examination and analysis tools such as OM (Optical Microscopy), UV (ultraviolet) and IR (infrared) photography, μ-EDXRF (Energy Dispersive X-ray Fluorescence), μ-Raman (Raman spectroscopy) μ-FTIR (Fourier Transform Infrared Spectroscopy) and SEM-EDX (Electron Scanning Microscopy with Energy Dispersive X-ray Spectroscopy). The conservation treatment focused on minimal intervention with the purpose of maintaining the integrity of a nineteen century painting that has never been restored until the present date. Simultaneously, a project to investigate the best back and front protection system for the PNP’s paintings collection was initiated. Relative Humidity (RH) and temperature fluctuations were measured in the Palace and inside the half-closed and fully closed systems used to protect twelve model paintings constructed for the purpose. The objective was to choose the best protection system for dampening RH and temperature fluctuations while preventing the risk of mould occurrence. The preliminary results (4 months of readings) showed that the risk of mould growth requires further study for in a more prolonged period which encompasses seasonal changes

Studying of the fluid's property adjustment and its application in metal foam industry

The main aim of this study is to find criteria influencing the shapes of a gas bubbles rising in stagnant liquid experimentally to form foam. A testing facility with the high-speed camera was designed. The results obtained are presented in terms of dimensionless parameters i.e. Reynolds's, Morton's and Eötvös. Factors varied to test their dependency such as nozzle diameter (3 - 5 mm), rate of flow rate (15 and 130 l/h), viscosity, surface tension and density were changed in order to see their effect on the shape of the bubble, its velocity in the liquid, surface tension force, drag force and buoyancy force. In order to vary such parameters a water-ethanol mixture was used in the tank. Also the foam formed was examined using water ethanol mixture in predicting the Foam bubble behavior in multi-phase flow. The study compares the concept of formation of foam at the surface of the mixture with the procedure of producing aluminum foam by direct gas injection. Material properties such as kinematic viscosity, density and surface tension on the foaming process will be studied experimentally, while the foam bubble size will be studied by means of digital image processing.The main aim of this study is to find criteria influencing the shapes of a gas bubbles rising in stagnant liquid experimentally to form foam. A testing facility with the high-speed camera was designed. The results obtained are presented in terms of dimensionless parameters i.e. Reynolds's, Morton's and Eötvös. Factors varied to test their dependency such as nozzle diameter (3 - 5 mm), rate of flow rate (15 and 130 l/h), viscosity, surface tension and density were changed in order to see their effect on the shape of the bubble, its velocity in the liquid, surface tension force, drag force and buoyancy force. In order to vary such parameters a water-ethanol mixture was used in the tank. Also the foam formed was examined using water ethanol mixture in predicting the Foam bubble behavior in multi-phase flow. The study compares the concept of formation of foam at the surface of the mixture with the procedure of producing aluminum foam by direct gas injection. Material properties such as kinematic viscosity, density and surface tension on the foaming process will be studied experimentally, while the foam bubble size will be studied by means of digital image processing.

Colour coded

This 300 word publication to be published by the Society of Dyers and Colourists (SDC) is a collection of the best papers from a 4-year European project that has considered colour from the perspective of both the arts and sciences.The notion of art and science and the crossovers between the two resulted in application and funding for cross disciplinary research to host a series of training events between 2006 and 2010 Marie Curie Conferences & Training Courses (SCF) Call Identifier: FP6-Mobility-4, Euros 532,363.80 CREATE – Colour Research for European Advanced Technology Employment. The research crossovers between the fields of art, science and technology was also a subject that was initiated through Bristol’s Festival if Ideas events in May 2009. The author coordinated and chaired an event during which the C.P Snow lecture “On Two Cultures’ (1959) was re-presented by Actor Simon Cook and then a lecture made by Raymond Tallis on the notion of the Polymath. The CREATE project has a worldwide impact for researchers, academics and scientists. Between January and October 2009, the site has received 221, 414 visits. The most popular route into the site is via the welcome page. The main groups of visitors originate in the UK (including Northern Ireland), Italy, France, Finland, Norway, Hungary, USA, Finland and Spain. A basic percentage breakdown of the traffic over ten months indicates: USA -15%; UK - 16%; Italy - 13%; France -12%; Hungary - 10%; Spain - 6%; Finland - 9%; Norway - 5%. The remaining approximate 14% of visitors are from other countries including Belgium, The Netherlands and Germany (approx 3%). A discussion group has been initiated by the author as part of the CREATE project to facilitate an ongoing dialogue between artists and scientists. http://createcolour.ning.com/group/artandscience www.create.uwe.ac.uk.Related papers to this research: A report on the CREATE Italian event: Colour in cultural heritage.C. Parraman, A. Rizzi, ‘Developing the CREATE network in Europe’, in Colour in Art, Design and Nature, Edinburgh, 24 October 2008.C. Parraman, “Mixing and describing colour”. CREATE (Training event 1), France, 2008

Venom alkaloids against Chagas disease parasite: search for effective therapies

Chagas disease is an important disease affecting millions of patients in the New World and is caused by a protozoan transmitted by haematophagous kissing bugs. It can be treated with drugs during the early acute phase; however, effective therapy against the chronic form of Chagas disease has yet to be discovered and developed. We herein tested the activity of solenopsin alkaloids extracted from two species of fire ants against the protozoan parasite Trypanosoma cruzi, the aetiologic agent of Chagas disease. Although IC50 determinations showed that solenopsins are more toxic to the parasite than benznidazole, the drug of choice for Chagas disease treatment, the ant alkaloids presented a lower selectivity index. As a result of exposure to the alkaloids, the parasites became swollen and rounded in shape, with hypertrophied contractile vacuoles and intense cytoplasmic vacuolization, possibly resulting in osmotic stress; no accumulation of multiple kinetoplasts and/or nuclei was detected. Overexpressing phosphatidylinositol 3-kinase—an enzyme essential for osmoregulation that is a known target of solenopsins in mammalian cells—did not prevent swelling and vacuolization, nor did it counteract the toxic effects of alkaloids on the parasites. Additional experimental results suggested that solenopsins induced a type of autophagic and programmed cell death in T. cruzi. Solenopsins also reduced the intracellular proliferation of T. cruzi amastigotes in infected macrophages in a concentration-dependent manner and demonstrated activity against Trypanosoma brucei rhodesiense bloodstream forms, which is another important aetiological kinetoplastid parasite. The results suggest the potential of solenopsins as novel natural drugs against neglected parasitic diseases caused by kinetoplastids.Fil: Silva, Rafael C. M. Costa. Universidade Federal do Rio de Janeiro; BrasilFil: Fox, Eduardo G. P.. Universidade Federal do Rio de Janeiro; Brasil. South China Agricultural University; ChinaFil: Gomes, Fabio M.. Universidade Federal do Rio de Janeiro; Brasil. National Institutes of Health; Estados UnidosFil: Feijó, Daniel F.. Universidade Federal do Rio de Janeiro; BrasilFil: Ramos, Isabela. Universidade Federal do Rio de Janeiro; BrasilFil: Koeller, Carolina M.. Universidade Federal do Rio de Janeiro; Brasil. University at Buffalo; Estados UnidosFil: Costa, Tatiana F. R.. Universidade Federal do Rio de Janeiro; BrasilFil: Rodrigues, Nathalia S.. Universidade Federal do Rio de Janeiro; BrasilFil: Lima, Ana P.. Universidade Federal do Rio de Janeiro; BrasilFil: Atella, Georgia C.. Universidade Federal do Rio de Janeiro; BrasilFil: Rocha de Miranda, Kildare. Universidade Federal do Rio de Janeiro; Brasil. Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem; BrasilFil: Schoijet, Alejandra Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Alonso, Guillermo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: de Alcântara Machado, Ednildo. Universidade Federal do Rio de Janeiro; BrasilFil: Heise, Norton. Universidade Federal do Rio de Janeiro; Brasi

Technological enhancements to optometric clinical tests

A sizeable amount of the testing in eye care, requires either the identification of targets such as letters to assess functional vision, or the subjective evaluation of imagery by an examiner. Computers can render a variety of different targets on their monitors and can be used to store and analyse ophthalmic images. However, existing computing hardware tends to be large, screen resolutions are often too low, and objective assessments of ophthalmic images unreliable. Recent advances in mobile computing hardware and computer-vision systems can be used to enhance clinical testing in optometry. High resolution touch screens embedded in mobile devices, can render targets at a wide variety of distances and can be used to record and respond to patient responses, automating testing methods. This has opened up new opportunities in computerised near vision testing. Equally, new image processing techniques can be used to increase the validity and reliability of objective computer vision systems. Three novel apps for assessing reading speed, contrast sensitivity and amplitude of accommodation were created by the author to demonstrate the potential of mobile computing to enhance clinical measurement. The reading speed app could present sentences effectively, control illumination and automate the testing procedure for reading speed assessment. Meanwhile the contrast sensitivity app made use of a bit stealing technique and swept frequency target, to rapidly assess a patient’s full contrast sensitivity function at both near and far distances. Finally, customised electronic hardware was created and interfaced to an app on a smartphone device to allow free space amplitude of accommodation measurement. A new geometrical model of the tear film and a ray tracing simulation of a Placido disc topographer were produced to provide insights on the effect of tear film breakdown on ophthalmic images. Furthermore, a new computer vision system, that used a novel eye-lash segmentation technique, was created to demonstrate the potential of computer vision systems for the clinical assessment of tear stability. Studies undertaken by the author to assess the validity and repeatability of the novel apps, found that their repeatability was comparable to, or better, than existing clinical methods for reading speed and contrast sensitivity assessment. Furthermore, the apps offered reduced examination times in comparison to their paper based equivalents. The reading speed and amplitude of accommodation apps correlated highly with existing methods of assessment supporting their validity. Their still remains questions over the validity of using a swept frequency sine-wave target to assess patient’s contrast sensitivity functions as no clinical test provides the range of spatial frequencies and contrasts, nor equivalent assessment at distance and near. A validation study of the new computer vision system found that the authors tear metric correlated better with existing subjective measures of tear film stability than those of a competing computer-vision system. However, repeatability was poor in comparison to the subjective measures due to eye lash interference. The new mobile apps, computer vision system, and studies outlined in this thesis provide further insight into the potential of applying mobile and image processing technology to enhance clinical testing by eye care professionals

Analysis of Acoustic Scattering Layers In and Around Petermann Fjord, Northwest Greenland

In 2015 a major international collaborative expedition took place focused on understanding the processes associated with the recent rapid decline of the Greenland Ice Sheet (GIS) and the impact that this decline could have on global sea-level rise. The Petermann Expedition collected a broad range of data designed to characterize the Petermann Glacier system, a marine-terminating glacier with a floating ice tongue that has undergone dramatic changes in the last decade. During the expedition, sonars were used to map the seafloor and the water column, generating a continuous dataset over 30 days. The water column mapping revealed extensive acoustic scattering layers, so called because the components of the layer – typically zooplankton and fish – scatter acoustic energy when concentrated in layers in the water column. The scattering layer was observed to change depth in a geospatially consistent manner and corresponded to our general, but limited understanding of the complex circulation patterns in the study area. This unexpected observation became the research question investigated in this thesis: Is the distribution of the acoustic scattering layer observed in and around Petermann Fjord a proxy for spatial and temporal changes in water mass structure and interactions? In order to answer this question, we focused on four objectives: determine the geospatial distribution of the scattering layer, determine if light influences the scattering layer depth distribution, determine if there is a consistent relationship to water column structure and circulation, and investigate the components of the scattering layer for clues as to its make-up and subsequently any potential reasoning for its distribution. Understanding the distribution of water masses and their circulation patterns in Arctic fjords are critical to understanding the fate of floating ice shelves and the glaciers they buttress, as the most pronounced change is occurring where ice sheets are grounded below sea level due to enhanced interaction with warming ocean waters. However, our ability to predict future sea level rise is hampered by our limited knowledge of these glacial systems, including the regional water mass distribution and circulation responsible for that enhanced ocean-ice interaction. Indeed, quantification of melting processes at marine terminating glaciers represents the largest source of uncertainty in predicting global sea level rise (Church et al., 2013). Traditional methods of oceanographic observation provide relatively sparse information at high cost, whereas acoustic records are continuous and, if the observed relationship between scattering layer depth and regional hydrography holds true, can potentially provide information about circulation, productivity, and ocean dynamics over large areas from underway platforms. Evaluation of the scattering layer distribution focused on the continuous Simrad EK80 18 kHz split-beam echosounder sonar records (section 3.1.1.1). The top of the scattering layer was manually picked on each echogram, providing the latitude, longitude, and depth for the top of each layer (section 3.2.1) that were then plotted to show the geospatial and depth distribution. The resulting distributions (section 4.1) showed a recognizable geospatial pattern that was consistent with our understanding of the distribution of water masses. Broadly, there was a scattering layer generally present in the fjord along the coast of Greenland (eastern Hall Basin) and ringing central Hall Basin, and absent in northern Hall Basin, along the coast of Ellesmere Island (northern Nares Strait and western Hall Basin), central Hall Basin, and southern Nares Strait. The top of the scattering layer was significantly shallower in the fjord and along the coast of Greenland, deepening in the central ring and western Hall Basin (when it was present). We evaluated whether there was a linear correlation between the scattering layer depth and the bathymetric depth and slope (sections 3.1.1.2, 3.1.1.5, 3.2.2), but no correlation was found (section 4.2.1). The second objective was to determine whether the scattering layer distribution was influenced by light rather than water mass distribution. This analysis was undertaken because of the typical association of scattering layers with daily migrations corresponding to daily light cycles as a means of predator avoidance (section 1.3.3). Though the expedition took place in Arctic summer during the ‘midnight sun’ regime of 24-hour light, there was enough daily change to discern a cycle in the ship-based radiation data collected by a Photosynthetically Active Radiation (PAR) Sensor mounted on the roof of the ship’s bridge (section 3.1.2.2). The relationship between light levels and scattering layer depth was examined (section 3.2.3), finding no linear correlation (section 4.2.2). A second analysis was done to see if we could discern a difference in water clarity across the study area using satellite-derived Kd(490) data, the diffuse attenuation coefficient for downwelling irradiance at 490 nm (section 3.1.3), and evaluate its effect on the scattering layer depth. Though available data for this region was very limited and there was some evidence of higher attenuation in the fjord where the shallower scattering layers were typically located, no correlation between scattering layer depth and Kd(490) values was found (section 4.2.3). Thus, neither light levels nor water clarity were responsible for the depth distribution of the scattering layer. The third objective was to determine if there was a consistent relationship between water mass properties and scattering layer depth beyond that established by initial observations (section 1.1). Profiles of conductivity, temperature, and depth (CTDs) were collected at 46 sites during the expedition to provide information on water mass properties and facilitate interpretation of regional circulation (section 3.1.2.1). Plots of temperature versus salinity (T-S diagrams) and temperature and salinity versus depth were generated for each CTD location, and the average depth of the scattering layer for that location was overlain on the plots (section 3.2.5). Examination of the T-S diagrams revealed a pattern in scattering layer preference for specific sections of the water column (section 4.2.4). Of the 38 profiles with an associated scattering layer, 22 had scattering layers with a preferred depth range that fell in the deeper, warmer, saltier portion of the water column associated with Atlantic Water, where salinity and temperature (and therefore density) values were steady – we called this group the ‘homogeneous preference’ scattering layers, in reference to the lack of change or stratification in the water column. Twelve of the profiles had scattering layers with a preferred depth range that fell in the shallower, cooler, fresher portion of the water column associated with Winter Water (or more generally, the Arctic outflow), where salinity and temperature (and therefore density) were changing relatively quickly with depth – we called this group the ‘heterogenous preference’ scattering layers, in reference to the changing, or stratified, water column. Four of the profiles had scattering layers that fell right at the location where the water column properties were moving from stratified to steady. This group we refer to as ‘transitional’ scattering layers. The homogeneous preference scattering layers were found primarily in Hall Basin and the western side of the fjord mouth, areas associated with inflow of Winter Water and Atlantic Water from the Arctic Ocean to Nares Strait. The heterogeneous preference scattering layers were found in the fjord, an area associated with the influence of meltwater from the glacier (Petermann Glacier Water) and outflow from the glacier face through the fjord. Transitional preference layers were found primarily on eastern side of the fjord mouth, an area associated with meltwater-influenced outflow moving up along the coast of Greenland. Six of the profiles did not have an associated scattering layer, and all were found along the western edge of Nares Strait/Hall Basin, a region associated with low oxygen, cold, fast flow from the Arctic Ocean moving south through Nares Strait. These results show a clear relationship between the scattering layer depth and regional water column structure and circulation (Conclusions, Chapter 5). The final objective was to investigate, if possible, what the scattering targets in the layers were (section 3.2.6). Target strength analysis of individual targets visible in and around the scattering layers in the EK80 data showed average target strengths of -42.04 to -44.04 dB (section 4.3.2). Estimates of volume scattering for larger sections of the scattering layer were fairly weak, 57.17 to -81.70 dB (section 4.3.2). The high individual target strengths and visual observations of single targets in the echograms (section 4.3.1) seem to indicate larger targets, with a strong possibility being Boreogadus saida, polar cod. The low volume scattering values and density estimates made using the volume scattering and individual targets strength values, however, do not seem to indicate that the visually dense scattering layers in the echograms were composed entirely of these fish, so we believe the scattering layers may be a mix of fish interspersed with smaller fish and zooplankton (Conclusions, Chapter 5). All analyses described in this thesis was complicated by the fact that this was a ‘dataset of opportunity’, i.e., the objectives of this study were not at all part of the original work plan of the expedition. Water column sonar data were collected continuously, but that collection was focused on the search for gas seeps and secondary to the many other data collection efforts taking place on the expedition. Ship radiation data were collected as a matter of course but via an uncalibrated instrument not intended for this expedition. Lack of water clarity data led to the use of remotely sensed data to attempt to estimate this parameter, and lack of biological sampling pushed us to dig into the echograms for clues as to the scattering layer components, as no ground truthing of either parameter was available. Despite these complications and imitations, we were able to extract useful information from the data and clearly demonstrate that acoustic records such as these can be used to show patterns in water mass distribution and circulation and provide clues to biological communities in this region. Optimizing water column profiling for these objectives opens up the potential of using a rapidly-acquired acoustic remote sensing technique to provide critical information on water mass distribution as a standard underway tool

Fluorescence Methods for Investigation of Living Cells and Microorganisms

Fluorescence methods play a leading role in the investigation of biological objects. They are the only non-destructive methods for investigating living cells and microorganisms in vivo. Using intrinsic and artificial fluorescence methods provides deep insight into mechanisms underlying physiological and biochemical processes. This book covers a wide range of modern methods involved in experimental biology. It illustrates the use of fluorescence microscopy and spectroscopy, confocal laser scanning microscopy, flow cytometry, delayed fluorescence, pulse-amplitude-modulation fluorometry, and fluorescent dye staining protocols. This book provides an overview of practical and theoretical aspects of fluorescence methods and their successful application in the investigation of static and dynamic processes in living cells and microorganisms

Sensitive label-free and fluorescence cancer biomarker detection using one dimensional photonic crystal biochips

Biological and biochemical processes play a very important role in living organisms and their understanding is particularly important in medicine, biology and biotechnology. Optical biosensors hold great promise for solving challenging molecular recognition issues, such as the detection of biomolecules at very low concentration. In this framework, a direct measurement of the binding of analytes to a target molecule in biological samples is an essential step in diagnosis and in understanding how biomolecules interact under physiological conditions. In this thesis, I contributed to the development of an optical platform that combines label-free and fluorescence detection modes. Such a platform makes use of one-dimensional photonic crystals (1DPC) sustaining Bloch surface waves (BSW) to detect relevant cancer biomarkers in body fluids. BSWs are surface electromagnetic waves that propagate along the truncation interface between a 1DPC and an external medium (the analyte) and can be strongly confined with a significantly enhanced field at the surface. By exploiting such features, 1DPC sustaining BSW (BSW biochips) are used as optical transducers that convert refractive index changes and fluorescence emission at their surface into a measurable optical signal. After discussing the results of the platform development, I report on the use I made of BSW biochips to detect clinically relevant concentrations of Angiopoietin 2 and ERBB2 in different biological matrices. The aim of such a research endeavour is clear: to reveal cancer by means of integrated optofluidic structures before cancer reveals itself. In the case of breast cancer, for example, it is a fact that ERBB2 is a pivotal biomarker and targetable oncogenic driver associated with several different aggressive subtypes. To quantitate Angiopoietin 2 and soluble ERBB2, I developed and implemented specific sandwich detection assays in which the BSW biochips’ sensitive surface is tailored with monoclonal antibodies for highly specific biological recognition. In a second step, a second antibody quantitatively detects the bound analytes. The strategy of the present approach takes advantage of the combination of both label-free and fluorescence techniques, making bio-recognition more robust and sensitive. In the fluorescence operation mode, the platform can attain the limit of detection 0.3 ng/mL (1.5 pM) for ERBB2 in cell lysates, which is the most complex biological matrix studied in the present work. Such a resolution meets the international guidelines and recommendations (15 ng/mL) for diagnostic ERBB2 assays that in the future may help to assign more precisely therapies counteracting cancer cell proliferation and metastatic spread