http://hdl.handle.net/2027.42/78566 Wed, 22 May 2013 08:54:18 GMT 2013-05-22T08:54:18Z http://deepblue.lib.umich.edu:80/bitstream/id/280515/216680.gif http://hdl.handle.net/2027.42/78566 http://hdl.handle.net/2027.42/77726 Rydberg Atoms for Quantum Information. Younge, Kelly Cooper I examine interactions between ensembles of cold Rydberg atoms, and between Rydberg atoms and an intense, optical standing wave. Because of their strong electrostatic interactions, Rydberg atoms are prime candidates for quantum information and quantum computation. To this end, I study excitation dynamics in many-body Rydberg systems using a rotary echo technique similar to the echo sequences used in nuclear magnetic resonance schemes. In this method, a phase reversal of a narrow-band excitation field is applied at a ariable time during the excitation pulse. The visibility of the resulting echo signal reveals the degree of coherence of the excitation process. Rotary echoes are measured for several $n$D$_{5/2}$ Rydberg levels of rubidium with principal quantum numbers near $n=43$, where the strength of electrostatic Rydberg-atom interactions is sharply modulated by a F$ddot{rm{o}}$rster resonance. The Rydberg-atom interactions diminish the echo visibility, in agreement with theoretical work. The equivalence of echo signals with spectroscopic data is also examined. Applications of Rydberg atoms based on controlled interactions require a trapping device that holds the atoms at well-defined positions several microns apart. Rydberg atoms in ponderomotive optical lattices present a unique platform to meet this requirement, as well as to study properties and interactions of these highly excited atoms. Because the Rydberg electron is so loosely bound, the ponderomotive interaction for a Rydberg electron is very similar to a free electron. Ponderomotive lattices tailored to trap Rydberg atoms will allow new experiments in quantum information physics and high-precision spectroscopy. Microwave spectroscopy is used as a powerful technique to probe the motion and to verify trapping of Rydberg atoms in ponderomotive lattices. The potentials for non-degenerate, low angular momentum states, are used to obtain ensembles of Rydberg-atom trajectories in the lattice, and to simulate the spectra of microwave transitions of Rydberg atoms moving through the lattice. Additionally, adiabatic potentials are calculated for Rydberg atoms in one-dimensional ponderomotive lattices for a variety of atomic states and lattice parameters. The lattice induced mixing of nearly-degenerate, high-angular-momentum states is explained in terms of effective electric and magnetic fields. Fri, 01 Jan 2010 00:00:00 GMT http://hdl.handle.net/2027.42/77726 2010-01-01T00:00:00Z http://hdl.handle.net/2027.42/75749 Proprotein convertase expression and localization in epidermis: evidence for multiple roles and substrates Pearton, David J.; Nirunsuksiri, Wilas; Rehemtulla, Alnawaz; Lewis, S. Patrick; Presland, Richard B.; Dale, Beverly A. Specific proteolysis plays an important role in the terminal differentiation of keratinocytes in the epidermis and several types of proteases have been implicated in this process. The proprotein convertases (PCs) are a family of Ca 2+ -dependent serine proteases involved in processing and activation of several types of substrates. In this study we examined the expression and some potential substrates of PCs in epidermis. Four PCs are expressed in epidermis: furin, PACE4, PC5/6 and PC7/8. Furin is detected in two forms, either with or without the transmembrane domain, suggesting occurrence of post-translational cleavage to produce a soluble enzyme. In addition the furin active site has differential accessibility in the granular layer of the epidermis relative to the basal layer, whereas antibodies to the transmembrane domain stain both layers. These findings suggest that furin has access to different types of substrates in granular cells as opposed to basal cells. PC7/8, in contrast, is detected throughout the epidermis with antibodies to both the transmembrane and active site and no soluble form observed. A peptide PC inhibitor (dec-RVKR-CMK) inhibits cleavage of Notch-1, a receptor important in cell fate determination that is found throughout the epidermis. Profilaggrin, found in the granular layer, is specifically cleaved by furin and PACE4 in vitro at a site between the amino terminus and the first filaggrin repeat. This work suggests that the PCs play multiple roles during epidermal differentiation. Fri, 01 Jun 2001 00:00:00 GMT http://hdl.handle.net/2027.42/75749 2001-06-01T00:00:00Z http://hdl.handle.net/2027.42/75565 A Phase I Dose Escalation Trial of Gemcitabine with Radiotherapy for Breast Cancer in the Treatment of Unresectable Chest Wall Recurrences Suh, W. Warren; Schott, Anne F.; Hayman, James A.; Schipper, Matthew J.; Shewach, Donna S.; Pierce, Lori J. The purpose of this study was to determine the maximum tolerated dose (MTD) of gemcitabine when given concurrently with standard radiotherapy for the treatment of chest wall recurrences, and to compare actuarial rates of local-regional control with those achieved in historical controls. Patients with unresectable chest wall recurrences were enrolled in a phase I trial of concurrent gemcitabine and radiotherapy. Gemcitabine was increased at 150 mg/m 2 /week increments, starting at 300 mg/m 2 /week. Radiotherapy was delivered to the chest wall and regional nodes to a total of 60 to 70 Gy in 2 Gy daily fractions. Treatment toxicity was assessed and a comparison of treatment outcome was performed between study patients and historical groups treated with either radiotherapy alone or excision followed by radiotherapy. The dose-limiting toxicities of neutropenia and thrombocytopenia occurred at the second planned dose of 450 mg/m 2 /week after accrual of only six patients, resulting in a MTD of 300 mg/m 2 /week. Myelosuppression and skin desquamation were commonly observed. Actuarial rates of local-regional control were 100%, 50%, and 90% at 2 years for the gemcitabine with radiotherapy, radiotherapy alone, and excision followed by radiotherapy groups, respectively ( p  = 0.105). The difference among the Kaplan–Meier curves for overall local-regional control was statistically significant at p  = 0.007 in favor of combined gemcitabine and radiotherapy. The MTD of gemcitabine is 300 mg/m 2 /week when gemcitabine is delivered concurrently with radiotherapy for unresectable chest wall failures. This novel approach suggests excellent local-regional control when compared to historical controls. A phase II trial is warranted.  Sat, 01 May 2004 00:00:00 GMT http://hdl.handle.net/2027.42/75565 2004-05-01T00:00:00Z http://hdl.handle.net/2027.42/75500 Is Breast Irradiation Routinely Necessary Following Conservation Therapy of Breast Cancer? Pierce, Lori J.; Lichter, Allen S. Mon, 01 May 1995 00:00:00 GMT http://hdl.handle.net/2027.42/75500 1995-05-01T00:00:00Z