Advanced Television Research Program

Contains reports on ten research projects.National Science Foundation Grant MIP 87-14969National Science Foundation FellowshipAdvanced Television Research ProgramAT&T Bell Laboratories Doctoral Support ProgramKodak FellowshipU.S. Air Force - Electronic Systems Division Contract F1 9628-89-K-004

Clonal evolution of CD8+ T cell responses against latent viruses: relationship among phenotype, localization, and function

Human cytomegalovirus (hCMV) infection is characterized by a vast expansion of resting effector-type virus-specific T cells in the circulation. In mice, interleukin-7 receptor α (IL-7Rα)-expressing cells contain the precursors for long-lived antigen-experienced CD8(+) T cells, but it is unclear if similar mechanisms operate to maintain these pools in humans. Here, we studied whether IL-7Rα-expressing cells obtained from peripheral blood (PB) or lymph nodes (LNs) sustain the circulating effector-type hCMV-specific pool. Using flow cytometry and functional assays, we found that the IL-7Rα(+) hCMV-specific T cell population comprises cells that have a memory phenotype and lack effector features. We used next-generation sequencing of the T cell receptor to compare the clonal repertoires of IL-7Rα(+) and IL-7Rα(-) subsets. We observed limited overlap of clones between these subsets during acute infection and after 1 year. When we compared the hCMV-specific repertoire between PB and paired LNs, we found many identical clones but also clones that were exclusively found in either compartment. New clones that were found in PB during antigenic recall were only rarely identical to the unique LN clones. Thus, although PB IL-7Rα-expressing and LN hCMV-specific CD8(+) T cells show typical traits of memory-type cells, these populations do not seem to contain the precursors for the novel hCMV-specific CD8(+) T cell pool during latency or upon antigen recall. IL-7Rα(+) PB and LN hCMV-specific memory cells form separate virus-specific compartments, and precursors for these novel PB hCMV-specific CD8(+) effector-type T cells are possibly located in other secondary lymphoid tissues or are being recruited from the naive CD8(+) T cell pool. IMPORTANCE: Insight into the self-renewal properties of long-lived memory CD8(+) T cells and their location is crucial for the development of both passive and active vaccination strategies. Human CMV infection is characterized by a vast expansion of resting effector-type cells. It is, however, not known how this population is maintained. We here investigated two possible compartments for effector-type cell precursors: circulating acute-phase IL-7Rα-expressing hCMV-specific CD8(+) T cells and lymph node (LN)-residing hCMV-specific (central) memory cells. We show that new clones that appear after primary hCMV infection or during hCMV reactivation seldom originate from either compartment. Thus, although identical clones may be maintained by either memory population, the precursors of the novel clones are probably located in other (secondary) lymphoid tissues or are recruited from the naive CD8(+) T cell pool

Bush the transnationalist: a reappraisal of the unilateralist impulse in US foreign policy, 2001-2009

This article challenges the common characterisation of George W. Bush’s foreign policy as “unilateral.” It argues that the Bush administration developed a new post-9/11 understanding of terrorism as a transnational, networked phenomenon shaped by the forces of globalisation. This led to a new strategic emphasis on bi- and multilateral security co-operation and counterterrorism operations, especially outside of Afghanistan and Iraq, driven by the perceived need to counter a transnational security challenge present in multiple locations. This (flawed) attempt to engage with transnational security challenges supplemented the existing internationalist pillar of the Bush administration’s foreign policy. Highlighting the transnational realm of international relations and the ways in which the Bush administration was able to co-opt other states to tackle perceived transnational challenges also shows the high importance the administration attached to concerted action even as it frequented eschewed institutional multilateralism

A continuous DC-insulator dielectrophoretic sorter of microparticles

A lab-on-a-chip device is described for continuous sorting of fluorescent polystyrene microparticles utilizing direct current insulating dielectrophoresis (DC-iDEP) at lower voltages than previously reported. Particles were sorted by combining electrokinetics and dielectrophoresis in a 250μm wide PDMS microchannel containing a rectangular insulating obstacle and four outlet channels. The DC-iDEP particle flow behaviors were investigated with 3.18, 6.20 and 10μm fluorescent polystyrene particles which experience negative DEP forces depending on particle size, DC electric field magnitude and medium conductivity. Due to negative DEP effects, particles are deflected into different outlet streams as they pass the region of high electric field density around the obstacle. Particles suspended in dextrose added phosphate buffer saline (PBS) at conductivities ranging from 0.50 to 8.50mS/cm at pH 7.0 were compared at 6.85 and 17.1V/cm. Simulations of electrokinetic and dielectrophoretic forces were conducted with COMSOL Multiphysics® to predict particle pathlines. Experimental and simulation results show the effect of medium and voltage operating conditions on particle sorting. Further, smaller particles experience smaller iDEP forces and are more susceptible to competing nonlinear electrostatic effects, whereas larger particles experience greater iDEP forces and prefer channels 1 and 2. This work demonstrates that 6.20 and 10μm particles can be independently sorted into specific outlet streams by tuning medium conductivity even at low operating voltages. This work is an essential step forward in employing DC-iDEP for multiparticle sorting in a continuous flow, multiple outlet lab-on-a-chip device. © 2011 Elsevier B.V

Prediction of Soai Reaction Enantioselectivity Induced by Crystals of N-(2-Thienylcarbonyl)glycine

The enantioselectivity of the autocatalytic alkylation of 2-tert-butylpyrimidyl-5-carbaldehyde, initiated by chiral crystals of N-(2-thienylcarbonyl)glycine, is predicted computationally. The results are in accord with the correlation of the stereochemical outcome of the reaction and the absolute structure of the crystals determined by the anomalous dispersion of X-rays and circular dichroism spectroscopy

Effect of Oxygen Defects on the Catalytic Performance of VO_<i>x</i>/CeO₂ Catalysts for Oxidative Dehydrogenation of Methanol

In this work, CeO₂ nanocubes with controlled particle size and dominating (100) facets are synthesized as supports for VO_<i>x</i> catalysts. Combined TEM, SEM, XRD, and Raman study reveals that the oxygen vacancy density of CeO₂ supports can be tuned by tailoring the particle sizes without altering the dominating facets, where smaller particle sizes result in larger oxygen vacancy densities. At the same vanadium coverage, the VO_<i>x</i> catalysts supported on small-sized CeO₂ supports with higher oxygen defect densities exhibit promoted redox property and lower activation energy for methoxyl group decomposition, as evidenced by H₂-TPR and methanol TPD study. These results further confirm that the presence of oxygen vacancies plays an important role in promoting the activity of VO_<i>x</i> species in methanol oxidation