Natural extracellular matrices for tendon tissue engineering

Androjna, Caroline Cleveland State University 2005 해외박사(DDOD)

Tendon repair is limited by the availability of replacement alternatives that adequately regenerate a tendon to its native biological and mechanical state. Tissue engineering strategies offer alternatives for successful tendon reconstruction. One approach has been the in vitro development of a functional tendon alternative utilizing natural extracellular matrices (bioscaffolds) seeded with exogenous cells. Functional replacements can be developed in vitro if appropriate biochemical and physical stimuli are present in the tissue culture environment. In this work we have investigated the effect of in vitro mechanical conditioning on small-intestine submucosa (SIS) augmented with primary tendon cells (tenocytes). To achieve our objectives, the laboratory's existing bioreactor reactor system was redesigned to increase oxygen delivery. To address oxygen transport limitations in long-term in vitro cultures, a mathematical model of oxygen diffusion through a cell-seeded scaffold was developed. From the model and experimental oxygen diffusivity data for several natural extracellular matrices, a practical limit on the size of cell-seeded constructs to be cultured long term in vitro was made. This estimate was then used to generate constructs for our loading experiments. In vitro cyclic loading significantly increased the biomechanical properties (e.g. stiffness) of cell-seeded SIS constructs (129.1 +/- 10.2%) as compared to cyclic load constructs without cells (33.9 +/- 13.8%) and no load or static load constructs (with or without cells) (-5.7 +/- 10.7%, -7.5 +/- 11.3%, 34.0 +/- 15.2%, 33.4 +/- 10.7% respectively). Using the mechanical loading regime from this work as a basis, alternate in vitro loading paradigms, cell types (e.g. mesenchymal stem cells), and growth factor conditioning could be explored as a means to further improve SIS construct mechanical properties.

The comorbidity of learning disorders and juvenile delinquency: Consumer and professional perspectives

Hendrix, Todd D Cleveland State University 2005 해외박사(DDOD)

The goal of this study is to examine the relationship between learning disabilities and juvenile delinquency as perceived by the adolescents, parents, teachers, psychologists and probation officers involved. Several Rationales have been put forth to explain this relationship including the susceptibility rationale, however this rationale has been criticized due to its inability to be empirically substantiated. Part of the criticism of the Susceptibility Rationale has been its broad scope and failure to clearly define which characteristics may contribute to this susceptibility. The current research identifies characteristics believed to be most closely associated with the perceived susceptibility including impulsivity, frustration tolerance, poor problem solving skills and difficulties decoding social cues. However, whether these factors accurately reflect the relationship, and which factors are most closely related, remain in question. Part of this discrepancy may be due to the failure to include the perceptions of the adolescents diagnosed with learning disabilities that are involved with the juvenile justice system. This study examined the perceptions of these adolescents, as well as the parents and professionals working with them to help identify if the adolescent's perceived themselves as having problems with these characteristics, if the parents and professionals involved with these adolescents perceived them as having problems with these characteristics, and if these perceptions had any correlation with the adolescent's level of involvement with delinquent activity. The adolescent participants were given the BarOn EQ-i (BarOn, 1997) and the adult participants completed the BarOn EQ360 (BarOn, 2003), a companion instrument and their results were analyzed using a non-parametric correlation coefficient due to the limited sample size. The results indicated that the adolescents with learning disabilities who participated in the research did not view themselves as having any difficulties with impulsivity, frustration tolerance, problem solving skills or decoding social cues as measured by their responses on the BarOn EQi. However the adult participants, the parents, probation officers, and mental health professionals all viewed the adolescent participants as having significant difficulties with impulsivity, frustration tolerance, problem solving skills and decoding social cues, as measured by their responses on the BarOn EQ360. However none of the participant group's responses were shown to be significantly correlated with the adolescent participant's involvement with delinquent behavior.

Foster care adolescents: Examining perceptions of a model resiliency and life-skills training program

Martin-Grissom, Deborah A Cleveland State University 2005 해외박사(DDOD)

Vygotsky (1978) defined the process of learning as "...the distance between the actual developmental level as determined by independent problem solving and the level of potential development as determined through problem solving under adult guidance or in collaboration with more capable peers." This dissertation examined the role of learning resiliency and life skills in adolescents who were involved with the foster care system and their subsequent impact on successful adult outcomes. Over the last ten years, empirical researchers have found an increase in the number of children in the United States being victims of sexual, physical, and emotional abuse, which has led to an increase of the number of children being placed in foster care. Additionally, minority children are over-represented in the foster care system, and adolescents make up almost one-half of the foster care population (Haerian, 1998; Terpstra &. McFadden, 1993). Empirical evidence also shows that childhood experiences of abuse and neglect are positively correlated with poor developmental outcomes, including serious and violent juvenile delinquency (Jonson-Reid & Barth, 2000). To this end, adolescents in foster care are at higher risk for failure in adulthood, (e.g., homelessness, welfare dependency, and incarceration), following their emancipation from foster care (Mech, 1988; Moynihan, 1988). When many of these adolescents are emancipated from foster care, and attempt to integrate into adulthood and mainstream society, they encounter difficulties, as they are not prepared to function independently as adults (Johnson-Reid, 1998). This study investigates the impact of a model training program on the resiliency and life skills of adolescents in foster care.

Vibration-based crack-induced damage detection of shaft-disk systems

Wu, Xi Cleveland State University 2005 해외박사(DDOD)

The objective of this dissertation is development of vibration-based crack detection strategies for on-line condition monitoring of rotordynamic systems. The dynamic response of a cracked Jeffcott rotor passing through the critical speed at constant acceleration is investigated analytically and numerically. The results of parametric studies of the effect of the crack depth, unbalance orientation with respect to crack, and the rate of acceleration on the rotor's response are presented. The dynamic behavior of the cracked rotor passing the resonance under a constant driving torque is analyzed by incorporating the coupling between the bending and torsional degrees of freedom. The effect of the crack depth on "stalling" of the rotor is investigated in details. The analysis of vibrational response of the cracked rotor employed nonlinear dynamics tools. The considered model accounts for nonlinear behavior of the crack and dynamic modes coupling. The finite element analysis of coupled lateral-torsional dynamic behavior of a rotor with two breathing cracks has been conducted for frequency analysis and response to excitation forces such as an externally applied torque. The variation of the stiffness matrix over the full shaft revolution is represented by Fourier series decomposition. The Fourier coefficient matrices are calculated from the stiffness matrices of the cracked shaft with the crack located at discrete angular locations based on fracture mechanics.

Analysis and numerical optimization of gas turbine space power systems with nuclear fission reactor heat sources

Juhasz, Albert J Cleveland State University 2005 해외박사(DDOD)

A new three objective optimization technique is developed and applied to find the operating conditions for fission reactor heated Closed Cycle Gas Turbine (CCGT) space power systems at which maximum efficiency, minimum radiator area, and minimum total system mass is achieved. Such CCGT space power systems incorporate a nuclear reactor heat source with its radiation shield; the rotating turbo-alternator, consisting of the compressor, turbine and the electric generator (three phase AC alternator); and the heat rejection subsystem, principally the space radiator, which enables the hot gas working fluid, emanating from either the turbine or a regenerative heat exchanger, to be cooled to compressor inlet conditions. Numerical mass models for all major subsystems and components developed during the course of this work are included in this report. The power systems modeled are applicable to future interplanetary missions within the Solar System and planetary surface power plants at mission destinations, such as our Moon, Mars, the Galilean moons (Io, Europa, Ganymede, and Callisto), or Saturn's moon Titan. The detailed governing equations for the thermodynamic processes of the Brayton cycle have been derived and successfully programmed along with the heat transfer processes associated with cycle heat exchangers and the space radiator. System performance and mass results have been validated against a commercially available non-linear optimization code and also against data from existing ground based power plants.

Molecular regulation of 23A2 skeletal myoblast differentiation and apoptosis

Freer, Margot C Cleveland State University 2005 해외박사(DDOD)

Skeletal myoblast apoptosis and differentiation are coordinately regulated. An overall goal of our lab is to the elucidate the pathways involved in the coordinate regulation of 23A2 skeletal myoblast differentiation and apoptosis with the purpose of inhibiting apoptosis without affecting differentiation to improve the efficacy of myoblast transfer as a treatment. The goals of this dissertation are twofold: firstly, to determine the Ras activated pathways involved in the inhibition of 23A2 skeletal myoblast apoptosis but not differentiation, and secondly, to identify the molecular pathways controlling apoptosis but not differentiation in 23A2 skeletal myoblasts. In chapter II we determined that 23A2 skeletal myoblasts stably expressing the constitutively active Ras mutant T35S (23A2:G12V:T35S:H-Ras) which selectively signals through the Raf/MEK/MAPK pathway, results in an acceleration of both differentiation and the associated apoptosis. We also found that activated Ras leads to the up-regulation of Dermo-1, p202, and RNaseL, proteins previously determined to be sufficient to abrogate differentiation and/or apoptosis. In chapter III, a detailed analysis of the processes of differentiation and apoptosis in 23A2 skeletal myoblasts led to the finding that when 23A2 skeletal myoblast are induced to differentiate, a maximum of 30% of cells undergo apoptosis. Furthermore, 23A2 skeletal myoblast differentiation and apoptosis are dependent upon both cell density and time in culture, and these variables are inversely related. Our lab has previously determined that 23A2 skeletal myoblast apoptosis requires new transcription, translation, and trafficking through the Golgi complex, while the release of cytochrome C only requires new transcription and translation. In chapter IV we have now determined that 9 pro-apoptosic Bcl2 family members are expressed in 23A2 skeletal myoblasts, and that 2 of these, Bax and PUMA are up-regulated following 3 hours of culture in DM. Finally, in chapter V we made the observation that 23A2 skeletal myoblasts stably expressing dnFADD or a dominant negative mutant of the TRAIL receptor DR5 (dnDR5) were differentiation defective, and expressed reduced levels of MyoD protein and mRNA. Treatment of 23A2 skeletal myoblasts with selective caspase inhibitors for caspases 3/7 and 8 also resulted in a down-regulation of MyoD protein and mRNA and a delay in differentiation. (Abstract shortened by UMI.).

An approach to information system security assessment

Chao, Shu-chuan Cleveland State University 2005 해외박사(DDOD)

As the tremendous growth of networks and e-business changes the nature of traditional information security threats, the capability to provide prompt and accurate information to authorized users boosts the competitive power of an organization. In addition to the threats, organizations face complex requirements in complying with security and privacy regulations. These conditions force organizations to seek more robust information security systems. An effective information security program, requires periodic security assessments. This study aims to develop an information security assessment model to evaluate the security level of an information security system. Based on respondents' comments, we choose higher education institutions as survey subjects. Utilizing literature reviews, information security standards, best practices, and information security assessment guides, we have formed the essential components of our information security assessment model. These components are organized as a two-layer structure---security controls and sub-security controls. In order to validate this model, we conducted two field studies and one web-survey. Based on the comments and number of responses, we chose higher education institutions as the survey subject for this study. The results of this study identify the different importance levels of security controls and sub-security controls. This model offers an improved security evaluation metric over extant methods. It also provides a potential baseline for the standard of information security metric. In this research, it does not only verify the varying importance levels of security controls and sub-security controls among different types of institutions but also in different sizes of organizations. This study also establishes a framework for information security assessment models for industries.

The effect of mechanical unloading on cultured tendon fascicles

Abreu, Eduardo Limongi Marques de Cleveland State University 2005 해외박사(DDOD)

Similar to other musculoskeletal tissues, tendons have the ability to adjust their constituents and structural design in response to changes in their mechanical environment, a phenomenon called remodeling . However, the cell-based mechanisms of load-associated remodeling are not well-understood. An organ culture in vitro model was developed and used to investigate the load-associated remodeling of tendons. Tendons were cultured in the absence of load (Unloaded group) or under low static load (Static group) for one week. We investigated remodeling at the organ, matrix and cell levels by evaluating mechanical (elastic and viscoelastic) properties, extracellular matrix composition and gene expression. In relation to control (Fresh group), the results showed that load deprivation decreased the elastic properties while a low static load increased the elastic properties and also changed the viscoelastic properties for both cultured groups. In terms of matrix composition, hyaluronan decreased in both cultured groups while chondroitin/dermatan sulfate glycosaminoglycan increased only in the Static group. There were no changes in collagen, water content in either cultured group and both cultured groups showed similar changes in gene expression pattern. Our results suggest that proteoglycans and other factors not evaluated, but not collagen, may be involved in the load-associated remodeling process at one week. Also, changes in gene expression seemed to be have been related to the culture environment and not to specific changes in mechanical load.

A case study of Head Start disability policy implementation

Harris, Jennifer L Cleveland State University 2005 해외박사(DDOD)

The passage of the 1972 Economic Opportunity Act Amendments mandated Head Start to make available enrollment opportunities of 10% for children with disabilities. Studies conducted immediately after the implementation of the legislation concluded that practices in centers were not consistent with the intent of the legislation. Children with severe disabilities were underrepresented while children needing minimal assistance were receiving services. Utilizing a case study approach this study evaluated the interpretation and implementation of disability policy at Central City Head Start. A series of interviews were conducted with staff in addition to a review of documents, including local policies and procedure statements, interagency agreements, expenditure reports for special education or related services, and statistical reports on the services provided to children with disabilities, to name a few. The findings of this study support the theory of policy implementation by Eugene Bardach (1977) in which he identifies policy implementation as a game where parties interact with one another in an effort to "win the game". Winning the game means compliance with the legislative mandate. The administrators of the Central City Head Start program believe they are in compliance because they have met the legislative mandate by confirming 10% of the children they serve have disabilities. In order to meet the mandate, staff unintentionally deflected the goals of the legislative mandate. As a result this had an adverse effect on the implementation of the legislative mandate. Children with severe disabilities at Central City Head Start were underrepresented; there was an over-reporting of children identified as having a disability, and a disproportionate number of children with speech and language impairments being served.

Optimal generator bidding strategies for power and ancillary services

Morinec, Allen G Cleveland State University 2005 해외박사(DDOD)

As the electric power industry transitions to a deregulated market, power transactions are made upon price rather than cost. Generator companies are interested in maximizing their profits rather than overall system efficiency. A method to equitably compensate generation providers for real power, and ancillary services such as reactive power and spinning reserve, will ensure a competitive market with an adequate number of suppliers. Optimizing the generation product mix during bidding is necessary to maximize a generator company's profits. The objective of this research work is to determine and formulate appropriate optimal bidding strategies for a generation company in both the energy and ancillary services markets. These strategies should incorporate the capability curves of their generators as constraints to define the optimal product mix and price offered in the day-ahead and real time spot markets. In order to achieve such a goal, a two-player model was composed to simulate market auctions for power generation. A dynamic game methodology was developed to identify Nash Equilibria and Mixed-Strategy Nash Equilibria solutions as optimal generation bidding strategies for two-player non-cooperative variable-sum matrix games with incomplete information. These games integrated the generation product mix of real power, reactive power, and spinning reserve with the generators's capability curves as constraints. The research includes simulations of market auctions, where strategies were tested for generators with different unit constraints, costs, types of competitors, strategies, and demand levels. Studies on the capability of large hydrogen cooled synchronous generators were utilized to derive useful equations that define the exact shape of the capability curve from the intersections of the arcs defined by the centers and radial vectors of the rotor, stator, and steady-state stability limits. The available reactive reserve and spinning reserve were calculated given a generator operating point in the P-Q plane. Four computer programs were developed to automatically perform the market auction simulations using the equal incremental cost rule. The software calculates the payoffs for the two competing competitors, dispatches six generators, and allocates ancillary services for 64 combinations of bidding strategies, three levels of system demand, and three different types of competitors. Matrix Game theory was utilized to calculate Nash Equilibrium solutions and mixed-strategy Nash solutions as the optimal generator bidding strategies. A method to incorporate ancillary services into the generation bidding strategy, to assure an adequate supply of ancillary services, and to allocate these necessary resources to the on-line units was devised. The optimal generator bid strategy in a power auction was shown to be the Nash Equilibrium solution found in two-player variable-sum matrix games.