Tracking migration during human T cell development

Specialized microenvironments within the thymus are comprised of unique cell types with distinct roles in directing the development of a diverse, functional, and self-tolerant T cell repertoire. As they differentiate, thymocytes transit through a number of developmental intermediates that are associated with unique localization and migration patterns. For example, during one particular developmental transition, immature thymocytes more than double in speed as they become mature T cells that are among the fastest cells in the body. This transition is associated with dramatic changes in the expression of chemokine receptors and their antagonists, cell adhesion molecules, and cytoskeletal components to direct the maturing thymocyte population from the cortex to medulla. Here we discuss the dynamic changes in behavior that occur throughout thymocyte development, and provide an overview of the cell-intrinsic and extrinsic mechanisms that regulate human thymocyte migration

Search for CPT and lorentz violation in B-0-(B)over-bar(0) oscillations with dilepton events

We report results of a search for CPT and Lorentz violation in B-0-(B) over bar (0) oscillations using inclusive dilepton events from 232x10(6) Upsilon(4S)-> B (B) over bar decays recorded by the BABAR detector at the PEP-II B Factory at SLAC. We find 2.8 sigma significance, compatible with no signal, for variations in the complex CPT violation parameter z at the Earth's sidereal frequency and extract values for the quantities Delta a(mu) in the general Lorentz-violating standard-model extension. The spectral powers for variations in z over the frequency range 0.26 yr(-1) to 2.1 solar day(-1) are also compatible with no signal