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Development of an In Vitro 3-Dimensional Co-Culture Human Colorectal Cancer Model in Microfluidic Devices
Get PDFColorectal cancer is the second most common cause of cancer-related deaths in the United States, with the relative 5-year survival rate for distant stage cancer being only 14%. The most common treatment for colorectal cancer is with chemotherapeutic drugs; however, the discovery of these drugs is costly, time-consuming, and often requires the use of animal models that do not yield results that translate to clinical trials. Due to these shortcomings, researchers seek to develop physiologically relevant in vitro tumor models that more accurately mimic the tumor microenvironment for cheaper and faster high-throughput drug screening. The aim of this research was to develop a colorectal cancer tumor model co-cultured with endothelial and stromal cells, followed by validation with clinically relevant chemotherapeutic agents within microfluidic devices. The first experiment consisted of a lipofection of fibroblasts to yield fluorescently tagged cells that could be later imaged using a fluorescence microscope. The next experiment consisted of a co-culture of tumor, endothelial, and fibroblast cells at varying densities in a twodimensional (2D) culture to determine the optimal plating densities that would yield quantifiable tumor and endothelial network formation. The following experiment used these optimal densities to test the effects of the chemotherapeutic agents oxaliplatin and SN38 on the tumor and endothelial cells in 2D. After the various densities and drug concentrations were tested in 2D, the model was introduced into microfluidic devices. The first experiment in the devices was similar to the first experiment plated in 2D, as it involved the establishment of optimal plating densities of all three cell types within the devices. Similarly, the goal of this experiment was to yield quantifiable tumor and endothelial network formation within the devices. The final experiment performed in this research was the introduction of oxaliplatin and SN38 to the optimized densities v of cells determined from the previous experiment, with the aim of evaluating the effects of these chemotherapeutic agents on the tumor and endothelial cells within microfluidic devices. The two experiments plated in 2D established plating densities to be tested in the devices. These experiments also showed that increasing drug concentrations resulted in reduced tumor count and size and revealed no disruption in the endothelial networks when exposed to oxaliplatin concentrations as high as 50 µM. The final two experiments in microfluidic devices revealed that endothelial network formation is not yet possible within the devices with the current protocols, but that tumor cells still showed dose-dependent responses to drug exposure as they did in 2D. Due to the lack of network formation in this device model, future work is required to allow for endothelial cell organization into networks, to further increase the physiological relevancy of this model to in vivo tumor conditions
The Impact of Culture on Construction
Get PDFThe aim of this comprehensive exploration is to identify elements within Japanese, Islamic/Arabic, and Tongan cultures that can be implemented into construction practices in California, leveraging their unique values to enhance home design and construction. The study reveals that culture plays a pivotal role in shaping the design and construction of homes, reflecting deeply held values, traditions, and societal norms. Through qualitative research, expert interviews, and a detailed literature review, key elements defining each cultural approach to housing are elucidated. From the emphasis on privacy and natural ventilation in Japanese homes to the integration of modesty and hospitality in Islamic/Arabic dwellings, and the communal living spaces of Tongan households, cultural influences shape every aspect of the built environment. By understanding and incorporating these cultural design elements, construction projects in California can attract a diverse range of prospective homeowners, offering living spaces that resonate with their cultural identities and values while promoting harmony with the environment
Effects of the 2022 California Building Energy Efficiency Standards on New Construction in San Luis Obispo County
Get PDFCalifornia released the first Building Efficiency Standards, or Energy Code, in 1976 and has updated them every three years. These standards aim at limiting the amount of energy use and greenhouse gas emissions by buildings in the state. California claims that these standards have saved consumers billions on utility bills, but there is limited information on the upfront impact the Efficiency Standards have had on new construction. This study sought to evaluate the impact that the 2022 California Building Energy Efficiency Standards had on new construction in San Luis Obispo County. Interviews were conducted with local specialty contractors in order provide quality data on some of the impacts the standards have had on construction as well as how the contractors track the Energy Code changes. Through the interviews it was concluded that contractors in the area don’t have the means to track specific cost and schedule associated with the Energy Code, but it was a general consensus that there would be a increase in cost and schedule of projects. It was also concluded that there was limited effect on the county due to the codes not having enough time to be implemented on the majority of new construction projects
Diminishing graduate student-teacher power dynamics through care and vulnerability
Get PDFIn this critical reflection, we discuss the concepts of ‘care’ (hooks, 1994) and ‘vulnerability’ (Cano Abadía, 2021) as they relate to the student-teacher power dynamics instructors often face – consciously or not – in graduate-level post-secondary contexts. We suggest that, when practiced together, care and vulnerability offer ways to diminish power imbalances between instructors and students
A Comparison Of Western And Eastern Soft Systems Approaches
Get PDFSoft System Approaches have been developed worldwide to help problem-solvers and decision-makers develop solutions to complex problems, such as aerospace systems. Soft System Approaches were designed to help lower the disorder of developing a complex system by increasing understanding of a situation. Four Soft System Approaches were investigated, two from the West and two from the East. Within the context of the paper, the West refers to thought patterns associated with thinkers and scientists in Europe and North America, and the East refers to those from and around China. The two from the West are Peter Checkland’s Soft Systems Methodology and Fran Ackerman and Colin Eden’s Strategic Options Development and Analysis, and from the East they are Qian Xuesen’s Meta-Synthetic Approach and Jifa Gu and Zhichang Zhu’s Wuli-Shili-Renli Approach. The four approaches were selected due to their prevalence and notoriety within the Soft System Approach research. The Western Soft System Approaches were created as a direct response to reductionism and are more holistic than Hard System Approaches; however, they are classified as systematic due to their structure. The approaches are tools that can be deployed for a specific task. Eastern Soft System Approaches rooted in Eastern philosophy went from holism to reductionism to a unity of the two. There is no one-size-fits-all approach; therefore, approaches that seek to balance reductionism and holism and give guidance and structure while inviting in other methods. The Eastern approaches are classified as framework Soft System Approaches, which provide structure and guidance but not a formula. Systematic approaches are better for determining a course of action, while framework approaches are better for guiding a whole program. The Eastern approaches covered can and do incorporate other methods, including each other. Depending on the problem and problem solver, the systematic or framework approach may be better suited. Overall, however, the framework approach will be able to solve the most varied problems due to the lack of prescriptiveness and the use of other approaches. Knowing the difference between the approaches and how they can be used helps manage the development of complex aerospace systems
Non-Linear Modeling of Hysteresis in Piezoelectric Actuated Cantilever Beam Using the Bouc-Wen Model
No full textPiezoelectric actuators frequently exhibit a time-dependent behavioral phenomenon known as hysteresis, resulting in a lag in the deformation of the actuator compared to linear models. The presence of hysteresis complicates control systems involving piezoelectric actuators. However, traditional modeling methods for piezoelectric actuated smart structures often treat the piezoelectric patches as linear actuators without considering hysteresis, leading to suboptimal controller performance.
This thesis aims to establish a comprehensive model by integrating the Euler-Bernoulli beam bending model with the hysteresis dynamics induced by two opposing piezoelectric patches attached to a beam. A model expansion method is employed to transform the partial differential equations describing beam vibration into a set of ordinary differential equations in the modal coordinate frame. These equations are then coupled with the Bouc-Wen model describing the hysteresis of piezoelectric materials.
Model parameters are identified using a genetic algorithm tested against experimental data across varied excitation frequencies. The experimental dataset is divided into two sets: a training set for the genetic algorithm and a validation set to verify the identified model. Results demonstrate that the inclusion of hysteresis in a nonlinear model provides better agreement with experimental results than the linear model, thereby enhancing the predictive capability of piezoelectric actuator behavior. This thesis has laid the foundation for future work on advanced control methods to mitigate beam vibration under external excitation, thus optimizing smart structure performance
Atascadero Little League - Snack Shack Window Renovation
Get PDFAtascadero Little League is an essential part of the local community. It brings families together and provides youth with a place to develop their social skills, sportsmanship, and discipline all while getting outside and exercising. Little leagues are non-profit organizations, managed and operated by volunteers, who sacrifice personal time to give back to their local community. Paloma Creek Park is where Atascadero Little League hosts most of their games. The snack shack’s service window does not face the baseball field, forcing volunteers to rely on a small window in the side of the structure to view their child’s game. The former design of the window was impractical for regular usage due to its heavy weight and lack of simple opening mechanics. Improving the snack shack window was something that Atascadero Little League had wanted done for a long time, and I was extremely excited to give back to an organization that had been an essential part of my life. For my senior project, I provided design options for the league’s board to choose between, coordinated jobsite access, procured the materials, and constructed the new window. Atascadero Little League provided funding for the materials used on the project
