Open Research Oklahoma (Oklahoma State Univ.)
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Parametric optimization of lattice structure heat sinks: An integrated computational and experimental approach
No full textLattice structures have frequently been investigated for their unique mechanical and thermal properties and have been optimized for better performance for these characteristics. Their mechanical properties have shown amazing results and have been thoroughly investigated in many comprehensive studies. However, trending research is now investigating their thermal properties, specifically for heat dissipation or insulation applications. To further build on this research, our approach considers the design, manufacturing, modeling, and characteristics to develop a lattice structure optimized for heat sink applications. Utilizing efficient technologies in additive manufacturing, we employ fused deposition modeling (FDM) as the method of fabrication. FDM is currently the most popular method of additive manufacturing due to its simplicity and price. A microscopy analysis of a PLA-copper-infused filament verified that parts from a low-cost FDM printer can produce parts over 80% copper after debinding and sintering heat treatments. Using a design of experimentations, we have identified 3 variables in lattice structures, strut diameter, cell size, and cell type, and optimized these heat sinks for evaluation parameters of heat sinks. Using a statistical analysis software Design Expert, we have designed and run multiple heat sinks through computational fluid dynamics (CFD) simulations to predict heat transfer to analyze the trends of these variables to develop a heat sink. Our results found three optimized lattice structure heat sinks that we validated through CFD. Our study found characteristics that can be used in further research and testing to develop low-cost additively manufactured heat sinks. The method we utilized can also be used for future research for efficiently optimizing heat sinks
Novel approach to identify inhibitors of iron acquisition systems of Pseudomonas aeruginosa
No full textPseudomonas aeruginosa is an opportunistic pathogen that has been declared by the World Health Organization as a “priority 1 critical pathogen” needing immediate new strategies for chemotherapy. During infection, P. aeruginosa uses redundant mechanisms to acquire ferric, heme (Hm), or ferrous iron from the host to survive and colonize. Significant efforts have been undertaken to develop siderophore blockers to inhibit ferric iron acquisition by P. aeruginosa, but there is a lack of inhibitors that can block Hm or ferrous iron acquisition by P. aeruginosa. We developed and employed a targeted high-throughput screen (HTS) and identified a molecule(s) that can specifically inhibit the Hm and ferrous iron acquisition systems of P. aeruginosa. Our targeted approach relies on screening a small-molecule library against P. aeruginosa under three growth conditions, where the only variable was the iron source (ferric, Hm, or ferrous iron). Each condition served as a counterscreen for the other, and we identified molecules that inhibit the growth of P. aeruginosa in the presence of only Hm or ferrous iron. Our data indicate that econazole, bithionate, and raloxifene inhibit the growth of P. aeruginosa in the presence of Hm and that oxyquinoline inhibits the growth of P. aeruginosa in the presence of ferrous iron. These iron-specific inhibitors do not interfere with the activity of meropenem, a commercial antipseudomonal, and can also increase meropenem activity. In conclusion, we present a proof of concept of a successful targeted conditional screening method by which we can identify specific iron acquisition inhibitors. This approach is highly adaptable and can easily be extended to any other pathogen. IMPORTANCE Since acquiring iron is paramount to P. aeruginosa’s survival and colonization in the human host, developing novel strategies to block the access of P. aeruginosa to host iron will allow us to starve it of an essential nutrient. P. aeruginosa uses siderophore, heme, or ferrous iron uptake systems to acquire iron in the human host. We have developed a novel approach through which we can directly identify molecules that can prevent P. aeruginosa from utilizing heme or ferrous iron. This approach overcomes the need for the in silico design of molecules and identifies structurally diverse biologically active inhibitor molecules. This screening approach is adaptable and can be extended to any pathogen. Since Gram-negative pathogens share many similarities in iron acquisition at both the mechanistic and molecular levels, our screening approach presents a significant opportunity to develop novel broad-spectrum iron acquisition inhibitors of Gram-negative pathogens.Microbiology and Molecular Genetic
Incorporating ruminants into cropping systems: effective utilization of nutrients from annual crops
Get PDFAs society debates the important issue of climate change and the utilization of natural resources, it is important to understand the need to further improve cropping and grazing systems to ensure that enough food is available for the growing population. Our experiments attempt to further improve these systems by understanding the effects of implant strategy in extended stocker cattle programs and subsequent carcass characteristics, the effects of water availability on stocker cattle grazing wheat pasture, and grazing preference and forage characteristics of summer annual cover crops in cattle, sheep, and goat pasture systems. From our results, no evidence was found to recommend an extended-release implant or stocker-phase reimplanting even in a relatively long grazing period, and producers should consider selecting the least cost implant protocol. Additionally, our results indicate steers deprived of drinking water are able to effectively utilize free-water in succulent forages; however, access to free-choice drinking water is advisable to minimize the likelihood of acute dehydration and optimize performance gains in stocker cattle grazing wheat pasture. Finally, our results demonstrate dietary preferences of common summer annual cover crops for cattle, sheep, and goats. Thus, cover crop mixtures can be formulated to provide preferred forage species for animal production and less preferred species for soil health
Custom design 10T SRAM using Skywater 130nm technology
No full textThe project’s main objective is to implement custom design 10T Static Random Access Memory (SRAM) using Skywater 130nm technology. SRAM commonly known as static RAM retains its data in its memory as long as the power is being supplied. SRAM has better performance and lower power usage when compared to DRAM (Dynamic RAM). One of the common applications is that it is commonly used for a computer’s cache memory such as the processor’s L2 and L3 cache. Other applications of the SRAM include peripherals such as printers, LCDs, cell phones, wearables, other consumer electronics, and network devices such as routers or switch. The custom design 10T SRAM structure consists of a standard 6T cell which has 2 PFETS with 2 gaps and a row of 4 NFETS with no gaps which expands to a 10T cell with 2 read ports and 1 write port (2R1W). The standard 6T SRAM which is commonly used in industry has the same single read and write ports thus the advantage of this 10T SRAM cell is that the separation of the read and write ports eliminates “readdisturb” by reading off a high impedance path. This implementation of the 10T SRAM will have better efficiency and potentially easy migration to smaller nodes (For example, nodes down to 2nm). It is also voltage scalable and will have high bandwidth per unit area multiport memory system as standard and helps to improve competitiveness in silicon design and implementation
Essays on pig value chain development in Vietnam
No full textThe two papers analyze the value chain of pigs in Vietnam and locating areas of intervention for traditional smallholder farmers. The first paper contributed to baseline information developed within the CGIAR Initiative SAPLING (Sustainable Animal Productivity for Livelihoods, Nutrition and Gender inclusion). Through an assessment of the different value chains for pigs in Son La, more targeted interventions could be identified and understood, with implementation enhanced by a broader understanding of the socio-economic and socio-cultural contexts of pigs utilizing a value chain approach. The second paper takes a more macro approach to analyzing trajectories of pig system change in Vietnam. In this paper, a multi-sector partial equilibrium model called the Vietnam Pig Model (VPM) was utilized. The paper utilizing VPM updates the earlier models to account for the changes that have taken place in the pig sector since the 2019 ASF outbreak. This paper shows the effects of supply, demand, imports, and exports under alternative scenarios of technology growth in each of the sectors (traditional, commercial, and modern) and how supply, demand, import, and exports are projected to be affected. Such technologies would improve productivity in the commercial and modern pig sector allowing the national demand of pork to be met with surplus used for export. Technological changes in the traditional smallholder sector will help to reduce prices and maintain market shares
Smart skin to treat and prevent pressure ulcers
No full textPressure ulcers (PUs), also known as bed sores, are injuries of the underlying tissue resulting from prolonged applied pressure on a bony prominence. One strategy to mitigate the risk of PUs is to reduce the peak pressure on the skin. Medical equipment, such as rotating mattresses, are designed to avoid these injuries, but they do not maintain quality of life or comfort for the patient. Our goal is to design a smart skin that relieves and redistributes points of peak pressure on the skin, using the nonlinear properties of Liquid Crystal Elastomers (LCEs). LCEs are a type of smart elastomer composed of liquid crystal molecules that react to stress and temperature by transitioning between different orientation phases. These phase transitions enable different mechanical behaviors within the material, including energy damping, soft elasticity, viscoelasticity, and shape memory actuation.The first step towards developing this smart skin is to characterize the mechanical behavior of LCEs in compression, specifically the mesogen orientation, the influence of crosslinking, and viscoelastic behavior. Local compression tests indicated that mesogens orient radially when loading is applied. Dynamic mechanical analysis tests revealed shape factor and crosslink density affect the mobility of the molecular chains, which alters the transition temperatures, relaxation times, and storage modulus. Uniaxial compression tests conveyed that crosslinking affects the tangent modulus and energy dissipation abilities.The second step is to measure the effectiveness of LCE smart skins by quantifying the decrease in peak pressure under human subjects’ heels. We recruited 26 healthy subjects (11 males and 15 females, Ages:18-25 years old, BMI<28). Each subject was asked to lie flat on their back on a testing surface while we measured the pressure under their heels with and without the smart skins in static and dynamic conditions. The peak pressure decreased when the smart skins were used, and recovery was based on the relaxation behavior of LCEs. Shifting positions impacted the weight distribution and performance of the smart skins, while creep had little effect
Fluid induced drilling dynamics: A mechanically scaled experimental investigation
Get PDFDrillstring vibration is an unavoidable detrimental dynamic response due to continuous acting external forces and dynamic loading applied during the drilling operations. Drillstring vibration is one of the primary reasons behind downhole equipment malfunctioning and premature fatigue failure. Laboratory scaled experiments gained much popularity to investigate the physics of induced vibrations by replicating the downhole vibrations phenomena, due to their economic design and versatility. The majority of laboratory scaled experiments oftentimes are only scaled geometrically and address isolated phenomena. Thus, most downscaled investigations provide limited insight and cannot relate to the overall dynamics of field conditions. The objective of this work is to design and fabricate a fully functioning mechanically scaled experiment and fulfill the experimental lacking of fluid hydrodynamic effects on drillstring vibrations. The developed experimental setup is equipped with a high-frequency vibration measurement system and the capability to capture the BHA trajectory. The setup was used to investigate the effect of WOB fluctuation on lateral motion and the effect of fluid flow on drillstring stability
Insights into translational regulation through tRNA sequencing, RNA sequencing, and ribosome profiling
No full textTranslation serves as an important layer of regulatory control, intricately influencing gene expression and protein functionality. Due to a phenomenon called, codon usage bias, highly expressed genes are believed to have codons that are translated more rapidly. As more than one codon can code for the same amino acid (synonymous codons), organisms may exhibit preferences for specific codons that facilitate increased expression of important genes and the translation speed of codons has been suggested to be linked to the availability of corresponding tRNAs. Furthermore, a new technique called ribosome profiling has recently permitted the study of the translatome, which refers to the entire population of mRNA associated with ribosomes for protein synthesis. This cutting-edge technique allows the identification of actively translated regions, but can also reveal translational pausing events that stem from the presence of SNPs. Interestingly, our previous research has demonstrated variation in tRNA expression across tissues and different states of health, leading us to consider the connection between tRNA abundance and translational stalling due to SNPs. By coupling ribosome profiling with tRNA sequencing and RNA sequencing, we can investigate all elements of translational machinery in order to predict translational efficiency, estimate proteome composition, and evaluate tRNA abundance as a source of genetic variation.
In this work, we utilized ribosome profiling, tRNAseq, and RNAseq and perform an integrative analysis in bovine tissues (kidney, liver and muscle) as well as murine myoblast cell lines (C2C12). By applying these methods to different bovine tissues, we were able to explore the interplay between tRNA availability and translational stalling events as well as genes subject to modulation at transcriptional and translational levels that underlie tissue specific biological processes. Through the implementation of these next generation sequencing (NGS) methods to cell culture, we were able to evaluate the translatome at various time points (0-min, 30-min, 60-min, and 4-hour) post-induction of differentiation. Where most studies have focused on molecular changes between differentiating myoblasts and multinucleated myotubes that are present 7 days after differentiation, we focus on the earliest stages of muscle differentiation that initiate muscle development and therefore kickstart the process of meat production
Metacognition training versus voices of role models: The impact on learning outcomes in chemistry
No full textConcerted efforts have called for the widespread adoption of evidence-based instructional practices (EIPs) to increase persistence, improve performance in undergraduate STEM classes, and prepare a competent STEM workforce. Consequently, there is overwhelming evidence of the adoption of EIPs in college chemistry classes. Unfortunately, most reported EIPs have been implemented as silo interventions, and therefore studies comparing the effectiveness of different EIPs on commonly measured learning outcomes are limited. The current study sought to address this gap. Specifically, the researcher investigated the impact of metacognition training versus the integration of voices of role models in chemistry on students’ 1) student performance in the General Chemistry I (GC I) and General Chemistry II (GC II); 2) sense of belonging in GC I and GC II and STEM programs, and perceptions of chemistry and science; and 3) learning experiences in the classes. A true experimental research design and a mixed-methods approach were employed. In both GC I and GC II, students were randomly assigned to two groups via Canvas based on gender, race/ethnicity, and first-generation status. For Group 1, in each class, students watched a video clip on metacognitive strategies. Group 2 watched four 2–7-minute video clips recorded by peer students, who previously passed the two classes, and two STEM professors (a Chemist—female and a Physicist—male). All the role models were from marginalized groups, and talked about the challenges they encountered in the two classes, how they navigated those challenges, and the resources they adopted to excel in these classes. The first video dosage was watched immediately after the students sat for Exam 1, and the second dosage of the same video clip(s) was watched after Exam 3 and a week before the final exam. Data sources included a structured survey, an open-ended reflection questionnaire, three in-term and final exam scores, and student demographic information, such as gender, first-generation status, and race/ethnicity. Findings indicated that for GC I, the role-model group significantly outperformed the metacognition group before the intervention (Exam 1), but the ‘opportunity’ gap was reduced with incremental doses of watching the metacognitive strategies video, even though the performance in the subsequent exams accompanied by the dosages of the videos was not statistically significant. In contrast, for GC II, although both groups performed nearly identically in Exam 1, the incremental doses of the role-models intervention seemed to boost the performance scores compared to the metacognition intervention. Detailed findings, including the reported sense of belonging and perceptions of chemistry and science, as well as implications for practice are discussed in this dissertation