Physics, Department of
http://hdl.handle.net/2027.42/69349
2016-11-19T11:31:06ZLectures on the symmetries and interactions of particle physics
http://hdl.handle.net/2027.42/117498
Lectures on the symmetries and interactions of particle physics
Wells, James D.
We build up Lorentz invariant and gauge invariant interactions of quantum fields consistent with symmetries. After that we discuss observables and their precision tests. And we conclude with a short discussion on Higgs boson theory and its discovery.
2013-07-04T00:00:00ZNatural Units Conversions and Fundamental Constants
http://hdl.handle.net/2027.42/117497
Natural Units Conversions and Fundamental Constants
Wells, James D.
Conversions are listed between basis units of natural units system where hbar = c = 1. Important fundamental constants are given in various equivalent natural units based on GeV, seconds, and meters.
2016-02-02T00:00:00ZRotationally invariant integrals of arbitrary dimensions
http://hdl.handle.net/2027.42/117496
Rotationally invariant integrals of arbitrary dimensions
Wells, James D.
In this note integrals over spherical volumes with rotationally invariant densities
are computed. Exploiting the rotational invariance, and using identities in the integration
over Gaussian functions, the general n-dimensional integral is solved up to a one-dimensional integral over the radial coordinate. The volume of an n-sphere with unit radius is computed analytically in terms of the Γ(z) special function, and its scaling properties that depend on the number of dimensions are discussed. The geometric properties of n-cubes with volumes equal to that of their corresponding n-spheres are also derived. In particular, one finds that the length of the side of such an n-cube asymptotes to zero as n increases, whereas the longest straight line that can fit within the cube asymptotes to a constant value. Finally, integrals over power-law form factors are computed for finite and infinite radial extent.
2014-09-10T00:00:00ZRaw data files for 'Growth conditions and cell cycle phase modulate phase transition temperatures in RBL-2H3 derived plasma membrane vesicles'
http://hdl.handle.net/2027.42/113066
Raw data files for 'Growth conditions and cell cycle phase modulate phase transition temperatures in RBL-2H3 derived plasma membrane vesicles'
Veatch, Sarah
Giant plasma membrane vesicle (GPMV) isolated from a flask of RBL-2H3 cells appear uniform at physiological temperatures and contain coexisting liquid-ordered and liquid-disordered phases at low temperatures. While a single GPMV transitions between these two states at a well-defined temperature, there is significant vesicle-to-vesicle heterogeneity in a single preparation of cells, and average transition temperatures can vary significantly between preparations. In this study, we explore how GPMV transition temperatures depend on growth conditions, and find that average transition temperatures are negatively correlated with average cell density over 15°C in transition temperature and nearly three orders of magnitude in average surface density. In addition, average transition temperatures are reduced by close to 10°C when GPMVs are isolated from cells starved of serum overnight, and elevated transition temperatures are restored when serum-starved cells are incubated in serum-containing media for 12h. We also investigated variation in transition temperature of GPMVs isolated from cells synchronized at the G1/S border through a double Thymidine block and find that average transition temperatures are systematically higher in GPMVs produced from G1 or M phase cells than in GPMVs prepared from S or G1 phase cells. Reduced miscibility transition temperatures are also observed in GPMVs prepared from cells treated with TRAIL to induce apoptosis or sphingomyelinase, and in some cases a gel phase is observed at temperatures above the miscibility transition in these vesicles. We conclude that at least some variability in GPMV transition temperature arises from variation in the local density of cells and asynchrony of the cell cycle. It is hypothesized that GPMV transition temperatures are a proxy for the magnitude of lipid-mediated membrane heterogeneity in intact cell plasma membranes at growth temperatures. If so, these results suggest that cells tune their plasma membrane composition in order to control the magnitude of membrane heterogeneity in response to different growth conditions.
2015-08-11T00:00:00Z