Design and Control Using Stochastic Models of Deposition Reactors

The financial feasibility of the creation of a start-up company to sell software developed for the optimization and in-line control of thin film growth in deposition processes was investigated. An analysis of the current marketplace revealed potential for a small start-up company to be competitive with this novel product. The investigation concluded an IRR of 20% for a five year period before possible sale of the company. The kinetic Monte Carlo method was employed as the basis for all simulations in this work. This method retains atomic scale information while enabling simulation of process relevant features such as roughness, growth rate and efficiency. A model predictive controller was designed to reproducibly generate thin films with desired properties under a variety of initial condition disturbances for both single component and multi component systems. The substrate temperature and gas flux were employed as control variables. The control algorithms were investigated using a sensitivity analysis and shown to be robust under a wide range of conditions

Novel Environment and GABA Agonists Alter Event-Related Potentials in N-Methyl-d-aspartate NR1 Hypomorphic and Wild-Type Mice

Clinical and experimental data suggest dysregulation of N-methyl-d-aspartate receptor (NMDAR)-mediated glutamatergic pathways in schizophrenia. The interaction between NMDAR-mediated abnormalities and the response to novel environment has not been studied. Mice expressing 5 to 10% of normal N-methyl-d-aspartate receptor subunit 1 (NR1) subunits [NR1neo(−/−)] were compared with wild-type littermates for positive deflection at 20 ms (P20) and negative deflection at 40 ms (N40) auditory event-related potentials (ERPs). Groups were tested for habituation within and across five testing sessions, with novel environment tested during a sixth session. Subsequently, we examined the effects of a GABAA positive allosteric modulator (chlordiazepoxide) and a GABAB receptor agonist (baclofen) as potential interventions to normalize aberrant responses. There was a reduction in P20, but not N40 amplitude within each habituation day. Although there was no amplitude or gating change across habituation days, there was a reduction in P20 and N40 amplitude and gating in the novel environment. There was no difference between genotypes for N40. Only NR1neo(−/−) mice had reduced P20 in the novel environment. Chlordiazepoxide increased N40 amplitude in wild-type mice, whereas baclofen increased P20 amplitude in NR1neo(−/−) mice. As noted in previous publications, the pattern of ERPs in NR1neo(−/−) mice does not recapitulate abnormalities in schizophrenia. In addition, reduced NR1 expression does not influence N40 habituation but does affect P20 in a novel environment. Thus, the pattern of P50 (positive deflection at 50 ms) but not N100 (negative deflection at 100 ms) in human studies may relate to subjects’ reactions to unfamiliar environments. In addition, NR1 reduction decreased GABAA receptor-mediated effects on ERPs while causing increased GABAB receptor-mediated effects. Future studies will examine changes in GABA receptor subunits after reductions in NR1 expression