The neurotoxin 6-hydroxydopamine (6-OHDA) is widely used to produce a neurochemically selective and progressive destruction of dopamine pathways. The resulting motoric deficits and histopathology reproduces several key features of Parkinson's disease, a neurodegenerative disorder for which there is no known cure. The objective of the present thesis was to characterize the in vivo neurotoxicity of 6-OHDA in dopamine pathways, and to examine the mechanisms underlying dopamine cell death. / Infusion of 6-OHDA into different dopamine pathways revealed that the nigrostriatal projection was more vulnerable than the mesolimbic dopamine pathway. In addition, a considerable portion of cell bodies was preserved despite significant losses of dopamine markers in nigrostriatal and mesolimbic nerve terminal regions. The partial sparing of cell bodies was enhanced by hypothermia associated with surgical anesthesia. This neuroprotective effect was localized to a specific subregion within the mesolimbic dopamine cell body area. The preservation of dopamine cell bodies following 6-OHDA administration may have functional significance since somatodendritic dopamine release has been demonstrated in this brain area. / The studies in Chapter 3 examined the contribution of two proteases, calpain and caspase-3, in mediating the degeneration resulting from 6-OHDA administration. Calpain activation occurred early and remained elevated in nigrostriatal cell body and terminal field subregions, whereas caspase-3 activation was only transient. Adenoviral delivery of the calpain inhibitor, calpastatin, completely prevented the elevation in calpain activity following 6-OHDA administration. Moreover, calpastatin delivery significantly improved motor deficits associated with nigrostriatal dysfunction. The behavioural protection was not, however, accompanied by a sparing of nigrostriatal dopamine markers, but was unexpectedly associated with a preservation of mesolimbic dopamine markers. These findings suggest that calpain activation contributes to dopamine cell death, but this effect may be brain region dependent. / Collectively, our findings highlight differential vulnerability amongst midbrain dopamine neurons, of possible relevance to Parkinson's disease. In addition, our work suggests that calpains may represent a future therapeutic target for the treatment of Parkinson's disease. However, present drawbacks associated with this approach indicate that additional studies are necessary before such neuroprotective compounds can be employed to treat Parkinson's disease.

Thesis, PlanB (M.S.)--University of Wisconsin--Stout, 2006. / Includes bibliographical references.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6719. Adviser: Sheldon H. Jacobson. Includes bibliographical references (leaves 139-142) Available on microfilm from Pro Quest Information and Learning.

Doctor of Philosophy / Department of Industrial and Manufacturing Systems Engineering / David Ben-Arieh / Group decision-making is an essential activity is many domains such as financial, engineering, and medical fields. Group decision-making basically solicits opinions from experts and combines these judgments into a coherent group decision. Experts typically express their opinion in many different formats belonging to two categories: quantitative evaluations and qualitative ones. Many times experts cannot express judgment in accurate numerical terms and use linguistic labels or fuzzy preferences. The use of linguistic labels makes expert judgment more reliable and informative for decisionmaking. In this research, a new linguistic label fusion operator has been developed. The operator helps mapping one set of linguistic labels into another. This gives decision makers more freedom to choose their own linguistic preference labels with different granularities and/or associated membership functions. Three new consensus measure methods have been developed for group decision making problem in this research. One is a Markov chain based consensus measure method, the other is order based, and the last one is a similarity based consensus measure approach. Also, in this research, the author extended the concept of Ordered Weighted Average (OWA) into a fuzzy linguistic OWA (FLOWA). This aggregation operator is more detailed and includes more information about the aggregate than existing direct methods. After measuring the current consensus, we provide a method for experts to modify their evaluations to improve the consensus level. A cost based analysis gives the least cost suggestion for this modification, and generates a least cost of group consensus. In addition, in this research I developed an optimization method to maximize two types of consensus under a budget constraint. Finally considering utilization of the consensus provides a practical recommendation to the desired level of consensus, considering its cost benefits.

Doctor of Philosophy / Department of Industrial & Manufacturing Systems Engineering / Zhijian Pei / Grinding is one of the important operations employed in modern manufacturing industry to remove materials and achieve desired geometry and surface finish. Simultaneous double side grinding (SDSG) and ultrasonic vibration assisted grinding (UVAG) are two typical cost-effective grinding processes which are utilized to grind semiconductor materials and high performance ceramic materials, respectively. The objectives of this research are to investigate several technical issues in modern grinding processes by using theoretical, numerical, and experimental research approaches. Those technical issues are related to SDSG and UVAG, which have been chosen as two typical grinding processes for this research. This thesis reviews the literature on SDSG (covering process applications, modeling of grinding marks, and modeling of wafer shapes) and UVAG (covering process applications, edge chipping, and coolant effects, etc). The theoretical research work of this thesis is conducted by developing mathematical models for grinding marks and wafers shapes in SDSG of silicon wafers. These developed models are then used to study the effects of SDSG parameters on the curvature of the grinding marks, the distance between adjacent grinding marks, and the wafer shapes. The numerical research work of this thesis is done by conducting a three dimensional (3-D) finite element analysis (FEA) of UVAG process. A 3-D FEA model is developed to study the edge chipping commonly observed in UVAG of ceramics. Edge chippings not only compromises geometric accuracy but also possibly causes an increase in machining cost. A solution to reduce the edge chipping is proposed based upon the FEA simulations and validated by pilot experiments. Several experimental studies are conducted to provide new knowledge for the UVAG process. Firstly, a novel coolant delivery system is explored for UVAG machine system. Secondly, UVAG is introduced into machining of fiber-reinforced ceramic matrix composites (CMC). Results of a feasibility study and a designed experimental investigation show that UVAG is a promising process for CMC machining. Finally, an experimental study on cutting forces during UVAG of zirconia/alumina composites is conducted. The feasibility to machine different zirconia/alumina composites using UVAG is also investigated and discussed. The findings in this thesis will provide theoretical and practical guidance for modern grinding processes especially for SDSG and UVAG.

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