Open Research Oklahoma (Oklahoma State Univ.)
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Mulching garden soils
No full textThe Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Interfacial effects on the chiral domain walls in ultrathin PT/CO/ALOₓ heterostructures for the futuristic spintronics devices
Get PDFHeavy metal /ferromagnet/metal oxide heterostructures are important due to their immense prospects for establishing spin textures such as chiral domain walls which are the basic ingredient of low power and capacious next-generation spintronics devices. The in-depth study of several spin interactions and magnetic parameters within those material systems is essential for the realization of such textures in the material stack. For that purpose, as detailed in this thesis, we constructed a cost-effective and sensitive vibration sample magnetometer (VSM) for magnetization measurement and explored crucial magnetic interactions that are important for future spintronics devices. Our work mainly concentrates on exploring the interfacial effects on the Dzyaloshinskii-Moria interaction (DMI), depinning fields, and other magnetic parameters for efficient DW motion in thin films made of Pt/Co/AlOₓ trilayers.In the first part of this thesis, we develop a low-cost magnetization characterization instrument using a sound card and compared its sensitivity with a commercial lock-in amplifier. Secondly, we report the dependence of the domain wall depinning field, domain wall velocity including anisotropy direction, and magnetic properties on the oxidized aluminum thickness of perpendicularly magnetized asymmetric Pt/Co/AlOₓ trilayers. The low-temperature magneto-transport measurement technique is also adopted to investigate the amount of oxygen at the Co/AlOₓ interface. It is found that the tendency of variation of cobalt oxidation at the interface is also consistent with the modification of the depinning fields, coercive fields and surface roughness measured at room temperature. At the end, we adopt the methodology to study the impact of cobalt oxidation at the Co/AlOₓ interface in Pt/Co/AlOₓ trilayer structures on the DMI by varying the post-growth annealing time, Al thickness and substrate. To quantify DMI magneto-optical imaging of the asymmetric domain wall expansion, hysteresis loop shift, and spin-wave spectroscopy techniques are employed. We further correlated the Co oxidation with low-temperature Hall effect measurements and X-ray photoelectron spectroscopy. Our results emphasize the importance of full characterization of the magnetic films that could be used for MRAM technologies when subjected to the semiconductor temperature processing conditions, as the magnetic interactions are critical for device performance and can be highly sensitive to oxidation and other effects
Investigation of cold atmospheric plasma for wound care
No full textThroughout the last decade, cold atmospheric plasma (CAP) has gained significant traction for aerospace and biomedical applications. The viability of CAP as a means for sterilization, and accordingly wound care, has made strides. There is a critical need for elucidation of the foundational mechanisms behind how CAP interacts with various cell types and surfaces to determine the pros, cons, and long-term viability of the technology for wound healing. In this study, a wound healing apparatus utilizing surface discharge actuators was designed and fabricated to perform laboratory testing. Pseudomonas aeruginosa (P. aeruginosa) and Methicillin-resistant Staphylococcus aureus (MRSA) were treated with CAP on plastic, glass, stainless steel, and aluminum and observed for differences in bacterial inactivation (BI) efficacy. BI testing resulted in stainless steel being more effective as a substrate for CAP treatment based on higher average absolute destruction of bacteria colonies. Two short studies on equine blood and mice skin were performed as a precursor and foundation for future studies that involve plasma x blood and plasma x skin interactions. Additionally, particle image velocimetry (PIV) was used to observe the flow field generated by the device for characterization and optimization of the flow. Several configurations and geometries, such as cylinders, threads, and meshes, were tested and observed for improvements in bacterial inactivation efficacy and mixing. The geometry and configuration of the plasma actuators were seen to have quantitative impacts in terms of BI efficacy and also showed high levels of form factor customizability of this technology. This study provides a wide breadth of preliminary research to lay the foundation for suggestions and recommendations for future research in CAP based wound care
Coping with restructuring or sale of the family farm
No full textThe Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Social functioning in children with ADHD: An examination of inhibition, self-control, and working memory as potential mediators
No full textThe study aims to explore the relative contributions of self-control, behavioral inhibition, and working memory deficits to ADHD-related social problems. Notably, the study adds to the current body of literature due to its use of a Go/No-Go (GNG) inhibition metric, working memory tasks with high central executive demands, and the unique inclusion of self-control. Fifty-eight children with attention-deficit/hyperactivity disorder (ADHD) and 63 typically developing (TD) children participated in the study. Self-control was measured via the task described in Patros et al. (2015), behavioral inhibition was measured using a Go/No-Go (GNG) task, working memory was measured using the Phonological Working Memory (PHWM) task, and parent and teacher social functioning was measured via the Social Problems narrow band scale of the Child Behavior Checklist (CBCL) and Teacher Report Form (TRF). Examination of potential indirect effects with the bootstrapping procedure indicated that the only significant mediator was PHWM for the relationship between group membership (ADHD, TD) and teacher ratings of child social functioning. These findings point to important implications regarding executive functioning difficulties at home compared to school as well as the use of measures that may have multicollinearity with each other (i.e., GNG versus Stop Signal Task). The current findings illuminate the need for more research related to working memory to help target social functioning interventions for children with ADHD
Effect of acid adaptation on pathogenic bacteria used as challenge organisms for microbial validation of biltong processing
No full textBiltong is a South African dried beef product that has grown in popularity in U.S. markets over the last five years. Unlike traditional American beef jerky, biltong is dried at ambient temperature and humidity after marination. However, the United States Department of Agriculture Food Safety and Inspection Service (USDA-FSIS) requires the use of heat lethality and maintenance of 90% relative humidity in a sealed oven to accomplish adequate reduction of pathogens on dried beef products for consumption. If these parameters are not met, such as is the case with biltong processing, a microbial validation study must be provided to demonstrate sufficient bacterial
reductions of a ‘pathogen of concern’ can be achieved. Moreover, the use of acid-adapted cultures during validation studies for acidic foods is ‘highly recommended’ by USDA-FSIS. It is widely thought if challenge cultures are not acid-adapted prior to acidic treatment the culture may react by being overly sensitive and result in falsely high microbial reductions. With this, communication with USDA-FSIS officials indicates that research demonstrating the importance of acid-adaptation would move USDA-FSIS guidelines to require acid-adapted cultures for industry process validation. Research done in our laboratory directly addressed this issue by performing process validation studies using acid-adapted and non-acid-adapted Salmonella serovars and Listeria monocytogenes serovars for biltong processing to determine whether acid-adaptation is a necessary pre-culture treatment prior to microbial validation studies. The data using Salmonella
serovars disproves the USDA-FSIS approach that non-acid-adapted cells would be more sensitive during an acid process treatment than acid-adapted cells. However, this relationship was not clear when using L. monocytogenes serovars as a biltong processing challenge culture.Lew Wentz FoundationAnimal and Food Science
NMR studies of membrane proteins
No full textNuclear magnetic resonance studies of membrane proteins yield valuable insights into their structure and topology. For example, the tilt angle and rotation of the helices in an ion channel can be determined by solid-state NMR spectroscopy in aligned lipid bilayers. Details about the structure of the protein in aligned phospholipids environments are immediately apparent from inspection of the SAMMY spectrum and the data can be further used for the determination of atomic resolution three-dimensional structures. SAR by NMR is a technique that is well suited for the field of membrane transporter proteins. The experiments on protein/phospholipid samples provide a unique insight into the interaction of drugs and the functional proteins.The advances required to transform solid-state NMR from a spectroscopic technique to a generally applicable method for determining molecular structures included multiple-pulse sequences, double-resonance methods, and separated local field spectroscopy. It also required improvements in instrumentation, especially the use of high-field magnets and efficient probes capable of high-power radio-frequency irradiations at high frequencies. The pace of development is accelerating and the local field is being utilized in an increasing number of ways in spectroscopic investigations of molecular structure and dynamics. Applications to many helical membrane proteins are underway and promise to add to our understanding of membrane proteins in health and disease.Chemistr
Full-body biomechanical model and novel forelimb muscle forces in Tyrannosaurus rex
No full textBackground: Tyrannosaurus rex is a popularly studied non-avian dinosaur with hundreds of papers investigating different aspects of its biology. The biomechanics of T. rex is of particular interest, with many analyses examining its locomotion and feeding. However, biomechanical models often focus on only one region of the body rather than incorporating multiple and some muscle groups have never been previously reconstructed in this taxon. Here we present (1) a new full-body model of Tyrannosaurus musculature, and (2) muscle force estimates for forelimb protractors and retractors, which have never yet been biomechanically analyzed. Methods: We created this model by generating a 3D render of a Tyrannosaurus rex’s skeleton with photogrammetry and sculpting the musculature onto the skeleton. The lengths and volumes of these scaled muscle models were then measured to calculate their physiological cross-sectional areas and ultimately estimate the maximum contractile force of each muscle for three possible fiber lengths. Results: The largest of the humeral protractors, the m. pectoralis, was estimated to have a maximum contractile force of 3,860 N – 11,000 N, while the largest humeral retractor, the m. latissimus dorsi, was estimated to have a maximum contractile force of 3,770 N – 10,800 N. Discussion: These forces will inform future calculations to explore how T. rex could use different muscle groups in its movements in addition to developing a better understanding of its forelimb biomechanics, which are largely undescribed. Furthermore, these muscle models will be presented as a digital atlas of T. rex’s skeletal muscle morphology
Margin of victory: A study of men’s college basketball analytics and its relationship to winning and losing
No full textBasketball is full of the unknown on how one team beats another team, that is why March Madness is so loved because of the unknown and madness involved. Basketball has been known for its vast amount of analytics collected during a games. College basketball is no exception to that. This study takes a deep dive into the analytics collected during the duration of a basketball game and which ones contribute more towards winning. Using historical data collected from Oklahoma State University box scores over the past 5 seasons. Running this data through SPSS and multiple regression to determine the predictive potential of the likelihood of wins based on one or more of the variables
Analyzing seasonal variations in benthic foraminifera in Budd Inlet, Puget Sound, Washington, U.S.A.
No full textCoastal and estuarine pollution has been a growing concern within this century. Benthic foraminifera have been commonly used as a bioindicator for waterway pollution because of their abundance, diversity, and relatively short lifespans. Researchers have found test abnormalities among benthic foraminifera in Budd Inlet in Puget Sound. Test abnormalities have typically been found in environments with high levels of heavy metals in the waterways often near anthropogenic sources of pollution. This thesis aims to document winter population diversity, abundances, and percentages of mutation of foraminifera in Budd Inlet, and compare them with past collections from summer months. The results of this study showed that the foraminifera from the summer season was much more abundant than the winter foraminiferal population. There were no test abnormalities in West Bay and East Bay and there were very few in Priest Point. Comparisons of the living and the dead assemblages documented much higher diversities in dead vs living populations, indicating different species must inhabit the region in either the fall or spring seasons as they have not been observed in the living populations collected in the winter or summer. These results suggest a significant gap in our understanding of foraminiferal ecology leading to future projects in the Puget Sound