No description available.

No description available.

No description available.

No description available.

No description available.

Tremendous growth in the biomedical science workforce has increased the need for trained scientists. The current workforce is severely underrepresented by minority groups, particularly Native Americans. To address this issue, the federal government funded programs that encouraged Native American students to participate in undergraduate biomedical science courses and research. One such program, funded by the National Institutes of Health, is the Minority Student Development Program at Northern Arizona University. Little research has been done on educational programs for minority populations. The purpose of this study was to identify and describe qualities and characteristics of the undergraduate research component of the federally funded Minority Student Development program from the perspective of Native American student participants. Qualitative case study methods were used to: (a) determine program qualities and characteristics, (b) develop a knowledge base about the experiences of Native American undergraduate student participants, ( c) identify career goals of students to determine if program participation influenced career choices, (d) understand the degree to which a student's cultural background influences career goals, and (e) evaluate the effectiveness of the program. Data were collected through interviews, observations, focus group discussions, informal discussions, questionnaire responses, meeting attendance, and document analysis. In all, 15 students, two program staff members, and eight faculty participated in the study. Findings from this study include a description of the background and experiences of three subjects: Leroy, Samantha, and Jeremy. While the three were selected for their Native American ethnicity, differences were discovered in their cultural experiences. The three subjects were positive about their program experiences. Career goals of students were greatly influenced by program participation. Findings related to program qualities and characteristics were identified and found to be closely aligned with stated program goals. Suggestions for program improvement included: (a) formalizing the application process, (b) matching student researchers with faculty mentors based on common research interests and personality, (c) faculty mentors closely supervising students to provide support and encouragement, and (d) communicating program expectations for students regarding conference attendance, presenting, and publishing research results.

Thesis (M.S.) --University of Texas Graduate School of Biomedical Sciences at San Antonio, 2008. / Vita. Includes bibliographical references.

Genetic engineering of artificial extracellular matrix (ECM) proteins represents an exciting avenue for the preservation and control of the specificity of natural polymers on a molecular level. This work focuses on controlling the mechanical and cell adhesion properties of artificial extracellular matrices intended for vascular graft applications. Genetic engineering methods were used for the design and preparation of artificial proteins containing sequences chosen to mimic elements of the ECM. The cell-binding domains (CBDs) of fibronectin impart biologic function, while an elastin-like repeat, [(VPGIG)2(VPGKG)(VPGIG)2] provides mechanical properties and sites for covalent crosslinking. Three proteins were constructed using this design that differ only by the CBD. The CBDs chosen for the proteins were the CS5 domain, the scrambled CS5 (SC5) domain, and the CS1 domain and are denoted by the respective CBDs. The SC5 protein was prepared as a negative control for the CS5 protein to assure cell adhesion was mediated by the CS5 domain. The CS1 domain binds the same integrin as the CS5 with a 20–100 fold higher affinity. Bis(sulfosuccinimidyl)suberate and disuccinimidyl suberate were used to crosslink protein films for mechanical testing. By varying the amount of crosslinker and protein weight fraction, films were prepared with Young's moduli ranging from 0.06 MPa to 0.97 MPa. The molecular weight between crosslinks (Mc) was calculated to lie between 3,000 and 38,000. The moduli and Mc of the proteins span the range reported for natural elastin. Thiolating the lysines in CS5 with N-succinimidyl S-acetylthioacetate allowed investigation of the effect of disulfide crosslinking on the mechanical properties. The modulus of the disulfide crosslinked films was 0.48 MPa corresponding to a Mc of 6000. Adhesion studies of human umbilical vein endothelial cells (HUVEC) showed increased and stronger adhesion to the CS5 protein over the SC5 protein. HUVEC adhesion to the SC5 was similar to the negative control (BSA) with very low or no adhesion. HUVEC adhesion to the CS5 ranged from the same as fibronectin to lower than fibronectin as the detachment force was increased. These studies indicated adhesion was mediated by the CBD since the proteins were otherwise identical.

Humans exploit dynamics—gravity, inertia, joint coupling, elasticity, and so on—as a regular part of skillful, coordinated movements. Such movements comprise everyday activities, like reaching and walking, as well as highly practiced maneuvers as used in athletics and the performing arts. Robots, especially industrial manipulators, instead use control schemes that ordinarily cancel the complex, nonlinear dynamics that humans use to their advantage. Alternative schemes from the machine learning and intelligent control communities offer a number of potential benefits, such as improved efficiency, online skill acquisition, and tracking of nonstationary environments. However, the success of such methods depends a great deal on structure in the form of simplifying assumptions, prior knowledge, solution constraints and other heuristics that bias learning. My premise for this research is that crude kinematic information can supply the initial knowledge needed for learning complex robot motor skills—especially skills that exploit dynamics as humans do. This information is readily available from various sources such as a coach or human instructor, from theoretical analysis of a robot mechanism, or from conventional techniques for manipulator control. In this dissertation I investigate how each type of kinematic information can facilitate the learning of efficient “dynamic” skills. This research is multidisciplinary with contributions along several dimensions. With regard to biological motor control, I demonstrate that motor synergies, i.e. functional units that exploit dynamics, evolve when trial-and-error learning is applied to a particular model of motor skill acquisition. To analyze the effects of velocity on dynamic skills and motor learning, I derive an extension to the notion of dynamic manipulability that roboticists use to quantify a robot's capabilities before specification of a task. And along the machine learning dimension, I develop a supervised actor-critic architecture for learning a standard of correctness from a conventional controller while improving upon it through trial-and-error learning. Examples with both simulated and real manipulators demonstrate the benefits that this research holds for the development of skillful, coordinated robots.

Flow injection and liquid chromatographic sample introduction techniques have been coupled to inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The analytical performances of these combinations have been evaluated. Several applications have also been developed. The fundamental FI parameter, response dispersion coefficient (D$\rm\sb{r}),$ has been studied for various elements with FI-ICP-MS in multi-element detection mode. Some interesting phenomena were observed and possible explanations have been made. A recirculating loop FI manifold which provides on-line successive dilutions has been coupled to ICP-MS. The analytical performance of the manifold was evaluated. The dilution behavior of various elements was examined. The manifold was successfully applied to the recovery study of cerium in wine. Factors affecting the speed of the dilution process were also investigated. High performance liquid chromatography including ion exchange chromatography (IC) and reverse phase liquid chromatography have also been coupled to ICP-MS for selenium speciation in selenium-enriched vegetables. The methods developed efficiently identified and semi-quantified several biologically important selenium species. The advantages and disadvantages of these methods were addressed as well. Flow injection sample introduction has also been coupled to an axially viewed ICP-OES with a segmented - array charge - coupled device detector. Various traditional pneumatic nebulizer-spray chamber systems have been examined. The best nebulizer-spray chamber combination has been identified for FI-ICP-OES. Some experiments and data treatments have been conducted under the guidance of simulation in order to achieve better analytical figures of merit.