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Gradient Preserved And Artificial Neural Network Method For Solving Heat Conduction Equations In Double Layered Structures
Get PDFLayered structures have appeared in many engineering systems such as biological tissues, micro-electronic devices, thin lms, thermal coating, metal oxide semiconductors, and DNA origami. In particular, the multi-layered metal thin lms, gold-coated metal mirrors for example, are often used in high-powered infrared-laser systems to avoid thermal damage at the front surface of a single layer lm caused by the high-power laser energy. With the development of new materials, functionally graded materials are becoming of more paramount importance than materials having uniform structures. For instance, in semiconductor engineering, structures can be synthesized from di erent polymers, which result in various values of conductivity. Analyzing heat transfer in layered structure is crucial for the optimization of thermal processing of such multi-layered materials. There are many numerical methods dealing with heat conduction in layered structures such as the Immersed Interface Method, the Matched Interface Method, and the Boundary Method. However, development of higher-order accurate stable nite di erence schemes using three grid points across the interface between layers for variable coe cient case is mathematically challenging. Having three grid points ensures that the nite di erence scheme leads to a tridiagonal matrix that can be solved easily using the Thomas Algorithm. But extension of such methods to higher dimensions is very tedious. Recently there have been some solution to such complex systems with the use of neural networks, that can be easily extended to higher dimensions. For the above purposes, in this dissertation, we rst develop a gradient preserved method for solving heat conduction equations with variable coe cients in double layers. To this end, higher-order compact nite di erence schemes based on three grid points are developed. The rst-order spatial derivative is preserved across the interface. Unconditional stability and convergence with O( 2 + h4) are analyzed using the discrete energy method, where and h are the time step and grid size, respectively. Numerical error and convergence rates are tested in an example. We then present an arti cial neural network (ANN) method for solving the parabolic two-step heat conduction equations in double-layered thin lms exposed to ultrashort-pulsed lasers. Convergence of the ANN solution to the analytical solution is theoretically analyzed using the energy method. Finally, both developed methods are applied for predicting electron and lattice temperature of a solid thin lm padding on a chromium lm exposed to the ultrashort-pulsed lasers. Compared with the existing results, both methods provide accurate solutions that are promising
In vivo and In vitro Expression and Interaction of the Mediator Kinase Module Subunits During Adipogenesis
Get PDFSelective gene expression is crucial in maintaining the self-renewing and differential potential of stem cells. Especially differentiation process requires a constellation of proteins that regulate expression of genes necessary for differentiation towards a specific lineage. Adipogenesis is a process of formation of mature fat cells from precursor cells that is tightly regulated by a number of transcription factors and their cofactors. Dysregulation in the process often leads to metabolic disorders, which is common due to prevalence of obesity. Mediator is a large, evolutionarily conserved, multi-subunit protein complex that functions as a transcriptional coactivator that modulates gene expression by relaying signals from cell type-specific transcription factors to RNA polymerase II. In humans, this complex consists of 30 subunits arranged in four modules. One critical module of the Mediator complex is the kinase module consisting of four subunits: MED12, MED13, CDK8, and CCNC. The kinase module exists in variable association with the 26-subunit Mediator core and affects transcription through phosphorylation of transcription factors and by controlling Mediator structure and function. Many studies have shown the kinase module to be a key player in the maintenance of stem cells that is distinct from a general role in transcription. Genetic studies have revealed that dysregulation of this kinase subunit contributes to the development of many human diseases. This research aims to demonstrate the importance of the Mediator kinase module by examining their expression and interaction with key adipogenic regulators during adipogenesis. It is hypothesized that the kinase module subunits have a role in adipogenesis of hASCs. As we look to use stem cells to understand human development and treat human disease through both cell-based therapies and tissue engineering, this research will address critical gaps in knowledge related to the molecular mechanisms that control cell fate
Loblolly Pine (Pinus Taeda) Leaf-level Physiology And the Influence of Genotype, Drought, and Thinning
Get PDFThe Southeastern U.S. is known as the “Wood Basket” for producing the vast majority of U.S. timber, but projected increases in the frequency of severe drought events could threaten timber plantations. Loblolly pine (Pinus taeda) is the principle timber species of the southeast and is distributed across the Atlantic Coastal Plains and west into Texas. Western Gulf states (LA, TX, AR, and OK) lie at the edge of the range for loblolly pine and are particularly vulnerable to any changes in precipitation or temperature. Current research suggests two main methods to increase plantation drought resistance: plant drought resistant seedlings or reduce tree density. This study seeks to evaluate whether genetic entry or plantation density management (thinning) has the capacity to ameliorate drought stress. Through a factorial design, the effect of drought on three genotypes at two density-levels was compared through examining leaf physiology. Leaf-level gas exchange parameters such as stomatal conductance (gs), maximum gross photosynthesis (Pgmax) and dark respiration (Rd) were measured seasonally, with an emphasis on summer months. For one summer, drought was simulated through trenching plot perimeters and constructing throughfall exclusion shelters to limit lateral water flow and precipitation, respectively. Our analysis found that each gas exchange parameter varied significantly between seasons. Significant genotypic differences were detected in Pgmax and Rd, but not gs. Following the initiation of drought simulation in June 2020, throughfall exclusion structures were successful at reducing the soil moisture of drought treatments by early August. Despite the reduced soil moisture, statistically significant effects of drought stress were not detected in gas exchange parameters. Even during the heavy precipitation from hurricane Laura, throughfall exclusion structures were able to maintain soil moisture differences between drought and non-drought treatments; however, the drought simulation was not able to push drought treatments past key ecological stress thresholds. We conclude that loblolly pine is indeed a very drought resistant species and that further evaluation is needed to understand genotypic differences in drought resistance and whether thinning can ameliorate plantation drought stress
The Role of Med31 and Med12 in Directing Adipogenesis of Human Adult-derived Mesenchymal Stem Cells
Get PDFSelective gene expression is crucial in maintaining the self-renewing and multipotent properties of stem cells. Mediator is a large, evolutionarily conserved, multisubunit protein complex that modulates gene expression by relaying signals from cell type-specific transcription factors to RNA polymerase II. In humans, this complex consists of 30 subunits arranged in four modules: head, middle, tail, and kinase. In our introduction, we show the state of the field of Mediator study with a focus on the critical kinase module. In the following chapters, we used siRNA knockdowns to investigate the roles of the highly-conserved core subunit MED31 and the kinase module subunit MED12 in directing cell state in human adult-derived mesenchymal stem cells harvested from either bone marrow or adipose tissue. Knockdown of MED31 resulted in a decrease in self-renewal based on cell assays and monitoring of gene expression and lipid vesicle formation. MED12 knockdown has produced similar results, but a potential interaction between MED12 and the master regulator of adipogenesis, PPARG, has been revealed through the application of delayed knockdown assays. These studies seek to expand our current understanding of stem cell behavior and how it relates to the critical Mediator complex in order to further progress toward stem cell therapies. In our final chapter, we show bioinformatics techniques that are rapidly transforming the field of biology that will also greatly impact the study of the Mediator complex in human stem cells
Hello, I am Jamie Newman
No full textDr. Newman is an Associate Professor of Biology in the School of Biological Sciences and the Associate Dean for Research and Graduate Studies in the College of Applied and Natural Sciences
Hello, we are Emily Theriot, Courtney Wessels, and Landry Seimears
No full textEmily Theriot, Courtney Wessels, and Landry Seimears are senior industrial engineering majors. Their senior design project is titled Examining the use of the DMAIC process on the operational plan improvement for UPS Personal Vehicle Drivers
Hello, I am Meredith Fisher
No full textMeredith Fisher is a sophomore majoring in Kinesiology and Health Sciences. The title of her project is: Blood Pressure Response in Police Officers
Hello, I am Todd Castleberry
No full textDr. Todd Castleberry is an assistant professor in the Department of Kinesiology
