Bose-Einstein condensates (BECs), with their superfluid behavior, quantized vortices, and high-level of control over trap geometry and other system parameters provide a compelling environment for studies of quantum fluid dynamics. Recently there has been an influx of theoretical and numerical progress in understanding the superfluid dynamics associated with two-dimensional quantum turbulence, with expectations that complementary experiments will soon be realized. In this dissertation I present progress in the development of an experimental toolkit that will enable such experimental studies of two-dimensional quantum turbulence. My approach to developing this toolkit has been twofold: first, efforts aimed at the development of experimental techniques for generating large disordered vortex distributions within a BEC; and second, efforts directed towards the design, implementation, and characterization of a quantum vortex microscope. Quantum turbulence in a superfluid is generally regarded as a disordered tangle of quantized vortices in three dimensions, or a disordered planar distribution of quantized vortices in two dimensions. However, not all vortex distributions, even large disordered ones, are expected to exhibit robust signatures of quantum turbulence. Identification and development of techniques for controlled forcing or initialization of turbulent vortex distributions is now underway. In this dissertation, I will discuss experimental techniques that were examined during the course of my dissertation research, namely generation of large disordered distributions of vortices, and progress towards injecting clusters of vortices into a BEC. Complimentary to vortex generation is the need to image these vortex distributions. The nondeterministic nature of quantum turbulence and other far-from-equilibrium superfluid dynamics requires the development of new imaging techniques that allow one to obtain information about vortex dynamics from a single BEC. To this end, the first vortex microscope constructed as part of my dissertation research enabled the first in situ images of quantized vortices in a single-component BEC, obtained without prior expansion. I have further developed and characterized a second vortex microscope, which has enabled the acquisition of multiple in situ images of a lattice of vortex cores, as well as the acquisition of single in situ images of vortex cores in a BEC confined in a weak hybrid trap. In this dissertation, I will discuss the state-of-the-art of imaging vortices and other superfluid phenomena in the University of Arizona BEC lab, as indicated by the examined performance of the quantum vortex microscope.

Two experiments explore the application of plasmonic nanoparticles to cellular pathology. The first devised a platform by which gold-silver nanoparticles act as differentiable labels for cell surface receptors under dark field imaging. By conjugating particles of various constitutions with receptor-targeting antibodies, particles scatter characteristically according to their plasmon peak. The second experiment programmed receptor placement via the patterning of two substrates and used the binding of SERS nanoparticles to explore the quantification of such targets at high-density. On one substrate, anchor pairs established receptors at specified distances in order to define the relationship between scattering intensity and the distance between SERS particles. On the second, anchor regions are filled with increasing densities of receptors and the particle-saturated substrates are probed to relate scattering intensity to particle density. This should discover the density-threshold between linear and non-linear scattering and inform the quantification of particles in the exponential density regime.

Two experiments explore the application of plasmonic nanoparticles to cellular pathology. The first devised a platform by which gold-silver nanoparticles act as differentiable labels for cell surface receptors under dark field imaging. By conjugating particles of various constitutions with receptor-targeting antibodies, particles scatter characteristically according to their plasmon peak. The second experiment programmed receptor placement via the patterning of two substrates and used the binding of SERS nanoparticles to explore the quantification of such targets at high-density. On one substrate, anchor pairs established receptors at specified distances in order to define the relationship between scattering intensity and the distance between SERS particles. On the second, anchor regions are filled with increasing densities of receptors and the particle-saturated substrates are probed to relate scattering intensity to particle density. This should discover the density-threshold between linear and non-linear scattering and inform the quantification of particles in the exponential density regime.

Introduction: This dissertation thesis aims to describe microcirculatory changes in cardiac arrest setting and to assess the impact of circulatory supports (i.e. mechanical chest compressions and extracorporeal membrane oxygenation (ECMO)) on tissue microcirculation. Methods and results: Two separate studies were designed. Microcirculation was monitored sublingually by a recent Sidestream Dark Field (SDF) technique and its parameters were evaluated offline, separately for small (of diameter ≤ 20µm) and other vessels. In order to monitor microcirculation during cardiac arrest (CA) and resuscitation (CPR) an experimental pig model was used; eighteen pigs were commenced to 3 minutes of untreated CA and subsequent 5 minutes of mechanical CPR. During CA the microcirculatory parameters deteriorated, in CPR they improved and reached 59 - 85 % of the prearrest values. The microcirculatory variables correlated neither to parameters of systemic circulation (mean arterial blood pressure and carotid blood flow) nor to lactate. In the second, clinical, study the sublingual microcirculation was monitored 29 (± 17) hours after the CA onset in 15 patients, who were after unsuccessful conventional CPR rescued by ECMO. In comparison to healthy (sex and age matched) volunteers, the patients showed mild but...

In this work, we use optical methods to study electrochemical reactions and processes occurring on the nanometer length scale. Optical methods are advantageous over traditional electrochemical methods because of their high spatial resolution and sensitivity at both the single nanoparticle and single molecule level. This dissertation describes a series of studies in which super-localization and dark-field optical imaging is used to provide insight into spatial and temporal heterogeneity in nanoscale electrochemical systems with <25 nm spatial resolution. In the first set of experiments, three-dimensional (3-D) super-resolution imaging is used to determine the tip-substrate distance in nanoscale scanning electrochemical microscopy (SECM) with precision better than 25 nm. Correlating the tip-substrate distance using both optical and electrochemical techniques showed excellent agreement. Second, single nanoparticles (NP) were delivered through a nanopipette, and their resistive-pulse signals were correlated with a fluorescence optical signal. The diffusion trajectories of individual NP delivered to the external solution and to an electrified interface were obtained by 3-D super-resolution imaging, and showed signatures of both sub-diffusive and super-diffusive behavior, depending on the balance of forces between the flow from the pipette and the applied potential at the electrified substrate. Next, we studied the influence of surface oxide layers on single silver NP electrodissolution by tracking the intensity and spatial variation of scattering from single nanoparticles over time. We discovered that silver NPs can undergo electrodissolution in either a spatially symmetric or asymmetric manner, based on the nature of the surface oxide layer. Moreover, we also reported the simultaneous electrodeposition of silver oxide at the electrode surface during the electrodissolution of silver NPs, which enabled us to study the effect of multiple simultaneous redox reactions and their effects on one another. Overall, these experiments reveal local heterogeneity in nanoscale electrochemical processes and allow for many single nanoparticles to be measured in parallel, revealing relationships that are hidden using traditional electrochemical measurements. / Chemistry

Transmission Electron Microscopy (TEM) on light element materials and soft matters is problematic due to electron irradiation damage and low contrast. In this doctoral thesis techniques were developed to address some of those issues and successfully characterize these materials at high resolution. These techniques were demonstrated on graphene flakes, DNA/magnetic beads and a number of water containing biomaterials. The details of these studies are given below. A TEM based method was presented for thickness characterization of graphene flakes. For the thickness characterization, the dynamical theory of electron diffraction is used to obtain an analytical expression for the intensity of the transmitted electron beam as a function of thickness. From JEMS simulations (experiments) the absorption constant λ in a low symmetry orientation was found to be ~ 208 nm (225 ± 9 nm). When compared to standard techniques for thickness determination of graphene/graphite, the method has the advantage of being relatively simple, fast and requiring only the acquisition of bright-field (BF) images. Using the proposed method, it is possible to measure the thickness change due to one monolayer of graphene if the flake has uniform thickness over a larger area. A real-space TEM study on magnetic bead-DNA coil interaction was conducted and a statistical analysis of the number of beads attached to the DNA-coils was performed. The average number of beads per DNA coil was calculated around 6 and slightly above 2 for samples with 40 nm and 130 nm beads, respectively. These results are in good agreement with magnetic measurements. In addition, the TEM analysis supported an earlier hypothesis that 40 nm beads are preferably attached interior of the DNA-coils while 130 nm beads closer to the exterior of the coils. A focused ion-beam in-situ lift-out technique for hydrated biological specimens was developed for cryo-TEM. The technique was demonstrated on frozen Aspergillus niger spores which were frozen with liquid nitrogen to preserve their cellular structures. A thin lamella was prepared, lifted out and welded to a TEM grid. Once the lamella was thinned to electron transparency, the grid was cryogenically transferred to the TEM using a cryo-transfer bath. The structure of the cells was revealed by BF imaging. Also, a series of energy filtered images was acquired and C, N and Mn elemental maps were produced. Furthermore, 3 Å lattice fringes of the underlying Al support were successfully resolved by high resolution imaging, confirming that the technique has the potential to extract structural information down to the atomic scale. The experimental protocol is ready now to be employed on a large variety of samples e.g. soft/hard matter interfaces.