Analysis of infected human mononuclear cells by atomic force microscopy

The surfaces of the human lymphoid cells of the line H9 chronically infected with the Human Immunodeficiency Virus HIV-1, and of human monocytes acutely infected in vitro with Mycobacterium Tuberculosis (MTB) were dried, fixed and imaged with atomic force microscopy (AFM). These images were compared with those of non-infected samples. Dried and fixed samples of infected cells can be distinguished from non-infected ones by AFM technology due to their different surface structures and by the presence of pathogenic (viz al or mycobacterial) agents on the cell surface

Atomic Force Microscopy of Neuron Networks

We imaged uncoated neuron networks by an atomic force microscope in the repulsive regime of contact mode. Images of granule cells and their axons have been clearly revealed with details smaller than 20 nm. The good stability of the sample and the mechanical reproducibility of the microscope allowed the imaging of a neuron culture area of several square microns. By combining tens of images, we were able to reconstruct a highly defined neuronal network. Furthermore, the images were very reproducible over repeated scanning acquisition, demonstrating the mechanical and thermal stability of the instrument-sample system

Collaborative digital and wide format printing : methods and considerations for the artist and master printer

This thesis investigates the collaborative production of fine art digital prints for artists,a process which is used by many contemporary practitioners including Richard Hamilton and Damien Hirst. Digital print as a fine art process has emerged over the last twenty years, and as yet, there is no in depth evidence on the collaborative endeavour and production process which is central to the digital Master Printer’s role. The investigation first establishes the historical context and significance of the Master and Printer in traditional printmaking, and the more recent development of the digital print studio and the digital print pioneers of the 1990s. A series of seven artists’ case studies in the context of the collaborative digital print studio are then offered to demonstrate the working process. The analysis of these proposes a best practice model for Master Printers working with contemporary artists to produce high quality, fine art, wide format inkjet digital prints. The study also compares production methods at the cutting-edge digital facility of the Rijksakademie in The Netherlands, to assess the validity of the practices proposed through a facility closest to the study’s research base at the CFPR’s digital studio. The comparative study also explored the expanding digital production process and the role of the Master Printer. Evolving production processes are also considered in this study as a response to the advancement of digital print technology alongside a practical exploration of what actually constitutes a digital print in this rapidly expanding field of fine art printmaking. This study aims to reveal the inner workings of the digital collaborative process between the artist and Master Printer, and appraise the digital Master Printer’s role. It offers a set of best practice methods for the digital Master Printer developed from this research. The study also considers how the digital print, and the digital print studio may evolve in line with current and future developments in new technologies.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Spectroscopic infrared scanning near-field optical microscopy (IR-SNOM)

Scanning near-field optical microscopy (SNOM or NSOM) is the technique with the highest lateral optical resolution available today, while infrared (IR) spectroscopy has a high chemical specificity. Combining SNOM with a tunable IR source produces a unique tool, IR-SNOM, capable of imaging distributions of chemical species with a 100 nm spatial resolution. We present in this paper boron nitride (BN) thin film images, where IR-SNOM shows the distribution of hexagonal and cubic phases within the sample. Exciting potential applications in biophysics and medical sciences are illustrated with SNOM images of the distribution of different chemical species within cells. We present in this article images with resolutions of the order of λ/60 with SNOM working with infrared light. With our SNOM setup, we routinely get optical resolutions between 50 and 150 nm, regardless of the wavelength of the light used to illuminate the sample

Infrared near-field microscopy with the Vanderbilt free electron laser: overview and perspectives

Scanning near-field optical microscopy (SNOM) makes it routinely possible to overcome the fundamental diffraction limit of standard (far-field) microscopy. Recently, aperture-based infrared SNOM performed in the spectroscopic mode,using the Vanderbilt University free electron laser,started delivering spatially-resolved information on the distribution of chemical species and on other laterally-fluctuating properties.The practical examples presented here show the great potential of this new technique both in materials science and in life sciences

Near-zone field effect of FIR laser radiation on tunnel current through the Schottky barrier under plasma reflection condition

Far infrared (FIR) radiation of high-power pulsed laser incident normal to the surface of GaAs/metal tunnel structures with a self-consistent Schottky barrier gives rise to a change in the tunnel conductance. It has been shown that the observed photoresistive effects are caused by ponderomotive forces of the radiation field on the free electron plasma in the junctions. The change of tunnel conductance rises linearly with increasing intensity at low power levels and proceeds into a strongly superlinear dependence at high intensities. It is shown that this superlinearity is a result of an enhancement of the local radiation field in the near zone of diffraction by inhomogeneities at the metal-semiconductor interface and depends strongly on the roughness of the metal electrode. Experimental results are compared to a nonlinear extension of the theory of electron redistribution due to the radiation pressure

A Method and Experimentation to Benchmark XR Technologies Enhancing Archeological Museum Experience

The use of eXtended Reality (XR) technologies, including augmented reality (AR), virtual reality (VR), and mixed reality (MR), has become increasingly popular in museums to enhance the visitor experience. However, the impact of XR technologies on Learning Performance in the context of archeological museums needs to be better understood. This study aims to investigate the relationships between Usability, Presence and Learning Performance by developing XR experiences showcasing archeological artefacts and conducting user testing to evaluate their effectiveness. A laboratory test is conducted to compare a VR application with a mobile AR one, presenting the digital models of five archeological findings. Descriptive statistics are used to compare the two case studies, providing valuable insights into the impact of XR technologies on the visitor experience from a learning perspective. The study confirms that Usability has a more significant effect on learning than Presence and can help designers and museum managers better understand the factors contributing to a successful XR experience. The findings suggest that while Presence is an important factor in improving visitors’ experience, Usability should be the priority when designing XR experiences for museums

Synthesis of scheelite nanoparticles by mechanically assisted solid-state reaction of wolframite and calcium carbonate

Nanostructured scheelite (CaWO4) was synthesized by calcination in air of enriched wolframite (Fe1-xMnxWO4) ore and calcium carbonate (CaCO3). The effects of process parameters such as milling conditions of the solid reactants, calcination in flowing or static air, and use of stoichiometric excess of calcium carbonate on wolframite conversion into scheelite were studied by X-Ray Diffraction (XRD) and field emission gun scanning electron microscopy (FEG SEM). The intimate mixing and associated decrease in the diffusion path by high-energy planetary ball milling (PBM) were responsible for the conversion of most of wolframite into nanostructured scheelite after 2 h at 600 °C, with no need of calcium carbonate stoichiometric excess. Complete conversion of PBM wolframite:CaCO3 mixtures into nanosized scheelite, iron oxide and carbon dioxide was accomplished after 2 h at 700 °C. The nanostructured scheelite obtained from wolframite is expected to be significantly more reactive in subsequent treatments (e.g., leaching) for tungsten extraction