CHEK1 inhibitors are currently in clinical trials for their ability to abrogate chemotherapy-induced CHEK1 activation and S phase arrest resulting in cancer cell apoptosis. No studies have yet identified ovarian cancers that could benefit from CHEK1-targeting therapy. I hypothesised that knowledge of CHEK1 and CHEK2 signalling in the DNA damage response can assist in identifying potential biomarkers for platinum responsiveness and CHEK-targeting therapy in ovarian cancer. In vitro studies investigated the CHEK1/2 inhibitor AZD7762 (AZD) and cisplatin (CP) in same patient-derived platinum-sensitive/resistant high-grade serous ovarian cancer cell lines (PEO1/PEO4 and PEO14/PEO23). Cytotoxicity assays confirmed higher CP IC50’s for PEO4 and PEO23 relative to PEO1 and PEO14 cell lines, respectively. AZD was more toxic to PEO1 cells and an additive effect of AZD with CP relative to CP alone was seen. A nontoxic AZD treatment to PEO4 cells sensitised the cells to CP when applied in combination. PEO14 and PEO23 cells had similar cytotoxicity profiles for combination treatments. BRDU DNA synthesis assays and cell cycle analysis revealed increased BRDU incorporation and accumulation in S phase when all cell lines were treated with CP. AZD treatment had a similar effect in PEO14 and PEO23 cells and increased the sub-G1 population, a marker of apoptotic DNA fragmentation, relative to control. Drug combination had no major effect on cell cycle distributions of both PEO14 and PEO23 cells relative to single agents but resulted in BRDU incorporation levels below CP and control levels for PEO14 cells. In PEO1 and PEO4 cells, AZD did not affect the cell cycle or DNA synthesis levels relative to control. Drug combination did not alter the cell cycle relative to CP treatment for PEO1 cells but decreased S phase and increased G2/M and sub-G1 populations in PEO4 cells. This was coupled with a decrease of CP-induced BRDU levels in PEO4 control levels. Apoptotic PARP cleavage/total PARP occurred early in CP treated PEO1 and PEO14 cells. A surrogate CHEK1/2 activity marker, p-CDC2 (Y15), decreased in all lines treated with AZD relative to control. Within PEO1 and PEO4 cells, greatest PARP cleavage was observed with combination treatment and coincided with high p-H2AX (S139), a DNA damage marker. p-CHEK1 (S317) and p-CHEK2 (T68), both ATR and ATM phosphorylation sites during DNA damage, increased for lone drug treatment and, to a greater extent, the combination drug treatments. PARP cleavage occurs across all treatments in PEO1 cells while it only occurs in the combination treatment for PEO4 cells. The latter coincides with a decrease in p-CHEK1 (S296) a CHEK1 autophosphorylation site, p-TP53 (S15), and p-BRCA1 (S1524), a homologous recombination marker, relative to the CP treated sample. In PEO14 and PEO23 cells, lone AZD and combination treatments had similar cleaved PARP/total PARP levels compared to the PEO14 CP treated cells. This was coupled with increased p-H2AX (S139), decreased CHEK1, and decreased CHEK2 autophosphorylation p-CHEK2 (S516). A human ovarian cancer xenograft model identified increases in p-H2AX (S139), CHEK1, p-CHEK1 (S317), p-CHEK2 (T68), and p-BRCA1 (S1524) in the carboplatin responsive cancers. In the paired pre- and post-chemotherapy human ovarian cancer samples, p-CHEK1 (S317) was elevated in post-chemotherapy responsive samples. In the first cohort, high p-CHEK1 (S317) was an independent poor overall survival biomarker and correlated with high p-H2AX (S139), MYC, p-CHEK1 (S296), p-CHEK2 (T68), p-CHEK2 (S516), and p-TP53 (S15). p-CHEK1 (S317) was associated with poor overall survival in serous ovarian cancers within the second pre-treatment ovarian cancer cohort. In conclusion, AZD can induce apoptosis in CP resistant cancer cells by synergising with CP to abrogate the S phase checkpoint, increase DNA damage, and inhibit CHEK1, and BRCA1 function. As a single agent, AZD can induce apoptosis by decreasing CHEK1 levels and CHEK2 activity. p- CHEK1 (S317) is a platinum responsive / poor prognostic biomarker.

The immune system’s vitality and function is of the upmost importance in the human body. The ingenuity and performance of this defence mechanism also plays a role in the prevention of mutated, transformed cells becoming malig- nant tumours (cancers). More recently, the subject of cancer immunology has been concerned with examining the local effects the immune system has on a pre-angiogenic tumour site. A recent immunological review article - “The Three Es of Cancer Immunoediting” - discusses the way the immune system interacts with cancer cells: elimination, equilibrium, and escape. This bio- logical explanation underpins the mathematical modelling in this PhD thesis where mathematical models of pre-angiogenic immune-tumour interactions are presented and analysed. Chapter two develops an individual-based model of immune-cancer cell interactions using the computational simulation plat- form, CompuCell3D, to extend an earlier spatio-temporal model of tumour dormancy (Matzavinos et al. [2004]). Chapter three investigates and analyses an ODE model of the interaction of two immune cells and two tumour cells. This model is extended to include spatial movement terms for the tumour and immune cells (in both one and two dimensions) and investigates the rich heterogeneous spatio-temporal dynamics of the system in the presence of a limit cycle in the reaction kinetics. Finally, chapter four extends the models in the previous two chapters by examining an individual based model of two immune cell populations interacting with two tumour cell populations.

In this thesis mathematical models describing the growth of a solid tumour in the presence of an immune response are presented. Specifically, attention is focused on the interactions between cytotoxic T-lymphocytes (CTLs) and tumour cells in a small, avascular multicellular tumour. At this stage of the disease the CTLs and the tumour cells are considered to be in a state of dynamic equilibrium or cancer dormancy. The precise biochemical and cellular mechanisms by which CTLs can control a cancer and keep it in a dormant state are still not completely understood from a biological and immunological point of view. The mathematical models focus on the spatio-temporal dynamics of tumour cells, immune cells, chemokines and “chemo-repellors” in an immunogenic tumour. The CTLs and tumour cells are assumed to migrate and interact with each other in such a way that lymphocyte-tumour cell complexes are formed. These complexes result in either the death of the tumour cells (the normal situation) or the inactivation of the lymphocytes and consequently the survival of the tumour cells. In the latter case, we assume that each tumour cell which survives its “brief encounter” with the CTLs undergoes certain beneficial phenotypic changes. We explore the dynamics of the model under these assumptions and show that the process of the immuno-evasion can arise as a consequence of these encounters.Our computational simulations suggest that the proposed mechanism is able to mimic various dynamics of immunoevasion during the lifespan of a mouse. We also highlight the differential spatiotemporal contributions to evasion due, respectively, to: i) a decrease in the probability pi of being lethally hit; ii) a decrease in the probability, embedded in k+ i , that a tumour cell is recognized by a CTL. In particular, our model suggests that a decrease in the parameters pi is needed to produce evasion, which does not occur in the case where pi remains constant at its baseline level inferred from the experimental data. However, the role of the parameters k+ i is important since it can greatly accelerate the simulated process. Moreover, our computational simulations also show that the proposed mechanism can also deeply affect the spatial patterning of the tumour. In particular, our model suggests that to have a uniform invasion profile for the tumour cells necessitates also having a decrease in the recognition rate, embedded in the parameters k+ i . These parameters also differentially shape the spatial distribution of the various classes of tumour cells. Also in this thesis, we discuss mathematical models of the interactions between a tumour and both the innate and the cellular part of the adaptive immune system. We have developed and formulated spatiotemporal models of the interactions between macrophages, natural killer cells, cytotoxic T lymphocytes and tumour cells. In addition to presenting computational simulations of our ODE and PDE models, we investigate the linear stability analysis of steady states of the model and the effect of the initial conditions on the behaviour of the ODE solution. We show that limit cycle behaviour could be obtained by making some changes in the parameter values, which gave us oscillations in the solution of the ODE and PDE systems. We observe that there is a slowly damped oscillation in the behaviour of the tumour, natural killer and CTL cells. Also we note that the solution converges to the second steady state where the tumour size is small (dormant state).A model of cancer invasion and metastasis is also discussed in this thesis. This model attempts to describe the interactions between cancer cells, urokinase plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1), plasmin, extracellular matrix (ECM) and the immune response. The mathematical model focuses on the effect of the immune response on cancer invasion by assuming that there is some form of limit cycle behaviour between the cancer cells and the effector cells. The work we present in this chapter develops a mathematical model for tumour invasion with an immune response using a continuum model in 1 and 2 space dimensions. This model consists of a system of nonlinear partial differential equations and examines the effector cell response the tumour invasion. This model consists of effector cells, tumour cells, ECM, uPA, PAI-1, and plasmin. First, we set all spatial components of the model to zero and consider only the reaction kinetics in order to compare between the behaviour of our model and the original Chaplain and Lolas model (Chaplain and Lolas, 2005). The spatially homogeneous simulation shows the behaviour of solutions have regular oscillations because there is a closed orbit. Second, we present the computational results of the spatio-temporal model, and we note from these simulations that the tumour size of our model is smaller than the tumour size of the Chaplain and Lolas model because the immune cells are interacting with the tumour cells, and also the degradation of ECM is less than that in the Chaplain and Lolas model. In addition, the number of tumour cell clusters in our model is less than those in the Chaplain and Lolas model. Also we found the tumour clusters of the mathematical model which was discussed in this chapter to have the same range than the tumour clusters of the Chaplain and Lolas model. The final model presented in this thesis is a mathematical model of cancer cells and effector cells which exhibit standing-wave behaviour between them. We show tha the wave of invading cancer cells can be stopped by the wave of effector cells or ECM.This model also focuses on the effect of the mutation of cancer cells to another subpopulation which is more malignant and which has the ability to invade the ECM or the effector cells to occupy space. The numerical simulations discussed in this chapter are essentially associated with an initial model of two equations representing the effector cells and tumour cells, such that there is a standing wave between these species. We note that the solution of the mathematical model is a travelling wave and also has a standing wave solution (i.e. the wave of effector cells stops the wave of tumour cells when they meet). This phenomenon occurs when the two diffusion coefficients are the same. We calculate the wave speed to illustrate that the speed tends to zero when the two waves meet - a positive speed of tumour cells refers to an invading tumour, and a negative speed refers to the decreasing of effector cells. After this we modify the model by adding an equation for a second cancer cell population T2, which is a sub-population 2 of tumour cells. This is to reflect the fact that cancer is a progressive disease, and as such it becomes more malignant as the cancer cells undergo successive mutations. We show in this case how the new type of cancer cells start to invade the effector cells after the failure of the first type. The third model discussed in this chapter is arrived at by adding an ECM equation to the second model, and it explains how the standing wave arise from two types of equations - the first one contains diffusion, and the second one has no diffusion.All the mathematical models in this thesis use numerical analysis of nonlinear partial differential equations and computational simulations to obtain insight into the underlying biological systems. The systems of nonlinear partial differential equations were numerically solved by a PDE solver in MATLAB for 1D and COMSOL for 2D. We used the MATLAB PDE solver pdepe which uses the method described in Skeel and Berzins (1990) for the spatial discretisation and the MATLAB routine ode15s for the time integration.The numerical simulations demonstrate the existence of cell distributions that are quasi-stationary in time and heterogeneous in space.

No description available.

For equating tests that measure several distinct proficiencies, procedures that reflect the multidimensional structure of the data are needed. Although there exist a few equating procedures developed under the multidimensional item response theory (MIRT) framework, there is a need for further research in this area. Therefore, the primary objectives of this dissertation are to consolidate and expand MIRT observed score equating research with a specific focus on the common-item nonequivalent groups (CINEG) design, which requires scale linking. Content areas and item types are two focal points of dimensionality. This dissertation uses two studies with different data types and comparison criteria to address the research objectives. In general, a comparison between unidimensional item response theory (UIRT) and MIRT methods suggested a better performance of the MIRT methods over UIRT. The simple structure (SS) and full MIRT methods showed more accurate equating results compared to UIRT. In terms of calibration methods, concurrent calibration outperformed separate calibration for all equating methods under most of the studied conditions.

No description available.

The roles of reading specialists differ from campus to campus throughout the study site due to varied implementations of Response to Intervention (RTI). To ensure that students were receiving consistent interventions based on their needs, the site needed to examine how and when instructional services were delivered to struggling students, as well as the role of the reading specialist in the process. The purpose of this qualitative case study was to explore the perceptions, experiences, and roles of reading specialists as the RTI framework was implemented at the elementary school level. This study was guided by Vygotsky's social constructivist learning theory, which holds that understanding is built through interactions, observations, and experiences. The research questions focused on the reading specialists' understanding of RTI, reading specialists' roles in RTI, challenges of implementing RTI, and professional development provided on RTI. Data were transcribed, categorized, open coded, and thematically analyzed. Member checks were used to strengthen the trustworthiness of the findings. Results revealed 5 major themes: understanding the RTI process, supporting struggling students, lack of funding and resources, collaboration/communication, and staff development. The findings can contribute to positive social change by leading administrators, instructional support teachers, and reading specialists to an increased understanding of the RTI process, and thereby improving RTI implementation procedures for struggling readers and subsequently increasing student achievement.

It is well documented that in the aftermath of a natural or human caused disaster, certain at-risk and vulnerable populations suffer significantly more than do other population groups. As a result, Congress enacted the Post-Katrina Emergency Management Reform Act (PKEMRA) in part to address deficiencies in providing aid to vulnerable populations, though little is known if the PKEMRA has resulted as it was intended. The purpose of this phenomenological study was to assess the impact of the PKEMRA on addressing emergency preparedness deficits related to at-risk and vulnerable populations. The theoretical framework followed Howard's conceptualization of game and drama theory. The research questions focused on the extent to which the PKEMRA recommendations improved disaster lifecycle outcomes for at-risk and vulnerable groups in Orleans Parish, LA between Hurricanes Katrina in 2005 and Isaac in 2012. Data were collected through semi-structured interviews of 5 emergency managers with knowledge and experience local to Orleans Parish, LA. Interview data were systematically reviewed using inductive coding and categorized for thematic analysis. Key study findings indicated that the improvements made to family location registries, evacuation procedures, and disaster resources for these populations in Orleans Parish were not a result of the PKEMRA, but of the state and local emergency agencies without input from the federal government. This study contributes to social change by promoting greater transparency of federal programs targeting at-risk and vulnerable populations, making direct recommendations to use Orleans Parish as a relevant example to address the needs of these populations. Such a review will serve as an exportable model for similar communities across the country.

Parents of transgender children face challenges when their children come out, including fear of negative reaction toward the parents and their transgender child by community members, concerns about social status in the community or religious organizations, and concerns about the inability of the transgender child to build his or her own family. The purpose of this qualitative phenomenological study was to investigate the emotional experiences of parents regarding their acceptance or rejection of their transgender child. Rohner's parental acceptance-rejection theory provided the framework for the study. Data were collected from parents (N = 13) who attended Parents and Friends of Gay and Lesbian support groups from various areas in the United States or who were identified through snowball sampling using semistructured interviews and a demographic questionnaire. Data were coded and analyzed to identify themes in parental responses to their transgender children coming out, which were either negative, neutral, positive, or mixed. Results indicated that even parents with negative emotions supported and loved their children unconditionally. Findings may be used to develop supportive interventions for parents coping with their transgender child's transition.

In this study, a theory that identified salience and immediacy as two constructs that significantly determine questionnaire response rates was tested. This theory emphasized the importance of identifying and rating factors that impact the immediacy and salience of a questionnaire to a specific population. It was proposed that factors that make a questionnaire highly immediate and salient to a given population should be identified first, and then implemented into the construction and administration of the questionnaire. In this way, researchers can manipulate the variables, which will maximize the response rate for their specific population before distribution. A questionnaire that is highly immediate and salient to a given population was estimated to achieve a response rate of 80% or higher. The immediacy and salience of several manipulable variables of a questionnaire were rated by a sample characteristically similar to the target population. Three treatments of the questionnaire were sent to three randomly assigned groups of the population. These treatments varied from low, moderate, to high immediacy and salience based on the ratings. An analysis of the ratings revealed a very strong direct relationship between salience and immediacy. Variables of the questionnaire were rated very similarly between the two constructs. Contrary to Christensen's theory, different levels of immediacy and salience were not found to interact. However, a direct relationship was found between immediacy and salience levels, and final response rates, which was consistent with the theory. The order of response rate percentages for each treatment group reflected the degree of immediacy and salience as measured by the raters.