Development of a cell population migration assay

Cellular migration is central to many physiological and pathological processes, from wound healing and the immune response to cancer cell invasion. Many in-vitro assays have been developed to study these processes and can be classified by the nature of the assay, for example migration of single cells or entire populations, as well as migration on a planar surface or through a 3D structure. This work concerns the development of an assay to study the migration of whole populations of cells across a deformable planar substratum, which may be coated in adsorbed adhesion molecules. The technique detailed below was developed from the Teflon fence assay

Surface modification of a polyether-urethane with RGD-containing peptides for enhanced cell attachment and signalling

Abstract of article examining the chemical modification of polyurethane with RGD-containing peptides offers a means of encouraging the adhesion, spreading and proliferation of cells cultured on its surface. This study assesses the efficacy of a modification procedure using surface analysis techniques and preliminary cell culture studies

Exact Study of the Effect of Level Statistics in Ultrasmall Superconducting Grains

The reduced BCS model that is commonly used for ultrasmall superconducting grains has an exact solution worked out long ago by Richardson in the context of nuclear physics. We use it to check the quality of previous treatments of this model, and to investigate the effect of level statistics on pairing correlations. We find that the ground state energies are on average somewhat lower for systems with non-uniform than uniform level spacings, but both have an equally smooth crossover from the bulk to the few-electron regime. In the latter, statistical fluctuations in ground state energies strongly depend on the grain's electron number parity.Comment: 4 pages, 3 eps figs, RevTe

3D reconstruction of the fundus of a phantom eye through stereo imaging of slit lamp images

In the detection of glaucoma, the second leading cause of blindness worldwide, the alteration of the optic disc's morphology is a key clinical indicator. The current gold standard test, stereo funduscopy using stereo fundus cameras, is subjective. Quantitative devices exist but are prohibitively expensive. Work carried out elsewhere has demonstrated quantitative results from stereo matching fundus camera images. Building on this idea, the slit lamp microscope (a mainstay of eye diagnostics, present in practically all ophthalmology and optometry practices) has the potential to be used as a quantitative device. This study explored the feasibility of uncalibrated 3D reconstructions of retinal structures of a phantom eye's fundus using a slit lamp

Disordered Hubbard Model with Attraction: Coupling Energy of Cooper Pairs in Small Clusters

We generalize the Cooper problem to the case of many interacting particles in the vicinity of the Fermi level in the presence of disorder. On the basis of this approach we study numerically the variation of the pair coupling energy in small clusters as a function of disorder. We show that the Cooper pair energy is strongly enhanced by disorder, which at the same time leads to the localization of pairs.Comment: revtex, 5 pages, 6 figure

Ultra-cold atoms in an optical cavity: two-mode laser locking to the cavity avoiding radiation pressure

The combination of ultra-cold atomic clouds with the light fields of optical cavities provides a powerful model system for the development of new types of laser cooling and for studying cooperative phenomena. These experiments critically depend on the precise tuning of an incident pump laser with respect to a cavity resonance. Here, we present a simple and reliable experimental tuning scheme based on a two-mode laser spectrometer. The scheme uses a first laser for probing higher-order transversal modes of the cavity having an intensity minimum near the cavity's optical axis, where the atoms are confined by a magnetic trap. In this way the cavity resonance is observed without exposing the atoms to unwanted radiation pressure. A second laser, which is phase-locked to the first one and tuned close to a fundamental cavity mode drives the coherent atom-field dynamics.Comment: 7 pages, 7 figure

Mesoscopic interplay of superconductivity and ferromagnetism in ultra-small metallic grains

We review the effects of electron-electron interactions on the ground-state spin and the transport properties of ultra-small chaotic metallic grains. Our studies are based on an effective Hamiltonian that combines a superconducting BCS-like term and a ferromagnetic Stoner-like term. Such terms originate in pairing and spin exchange correlations, respectively. This description is valid in the limit of a large dimensionless Thouless conductance. We present the ground-state phase diagram in the fluctuation-dominated regime where the single-particle mean level spacing is comparable to the bulk BCS pairing gap. This phase diagram contains a regime in which pairing and spin exchange correlations coexist in the ground-state wave function. We discuss the calculation of the tunneling conductance for an almost-isolated grain in the Coulomb-blockade regime, and present measurable signatures of the competition between superconductivity and ferromagnetism in the mesoscopic fluctuations of the conductance.Comment: 6 pages, 3 figures, To be published in the proceedings of the NATO Advance Research Workshop "Recent Advances in Nonlinear Dynamics and Complex System Physics.