Determination of the Structural and Functional Mechanisms of Perfluorocarbon-based Nanoemulsion Particle Interactions with Model Biomembrane Systems

Perfluorocarbon based nanoemulsion particles: PFC-NEPs) are very small sized: ~ 250 nm in diameter) greasy droplets that are enclosed by emulsifying phospholipid monolayer. PFC-NEPs have been extensively developed for target-specific delivery of therapeutic agents such as imaging agents and drug molecules. Because of the extremely small sizes of PFC-NEPs and fluid nature of their surface, the structure of these particles at atomic resolutions has yet to be determined by experimental approaches. The aim of this thesis is to determine the atomistic structure of PFC-NEP interfaces with a particular focus on their interaction with model target bilayers. The goal of this work is to help understand the molecular mechanisms for PFC-NEP cargo binding and delivery. Such understanding will enable the rational design of PFC-NEPs for optimal delivery and eventually lay a foundation to customize the particles for delivery of specific cargo molecules. To achieve this goal, we have used molecular dynamics: MD) simulations at both atomistic and coarse-grained levels using in-house force field parameters developed for a perfluorocarbon molecule that forms the emulsion core. By employing atomistic simulations, the PFC-NEP interface structure was determined in the absence and presence of a model cargo. The interface structure featured the intercalation of the PFC molecules into the emulsifying monolayer and differential cargo binding to the PFC-NEP interface as a consequence of the intercalation, which expressed the need to modulate the level of mixing of PFC with the emulsifying monolayer for cargo binding to PFC-NEPs. Coarse-grained MD simulations have been employed to test a proposed hemifusion mechanism for PFC-NEP delivery of cargo to target bilayers. Our simulations showed that PFC-NEP and liposome particles fused after encounter; distinct molecular details were observed from the fusion mechanism between two bilayers. This thesis research has not only provided the detailed structure to elucidate molecular mechanisms for cargo binding and delivery but also laid a foundation to decipher the correlation between the structure and function of PFC-NEPs for more systematic studies in the future

The impact of employee’s perception of organizational climate on their technology acceptance toward e-learning in South Korea

To better understand the relationship between e-learning integration and organizational factors in South Korea, this study explored the influence of employees’ perceptions of organizational climate on their technology acceptances toward e-learning in the workplace of South Korea. Employees’ perceptions of organizational climate was evaluated using Litwin & Stringer’s Organizational Climate Questionnaire (LSOCQ) and employees’ technology acceptance toward e-learning was measured by the Unified Theory of Acceptance and Use of Technology (UTAUT). A canonical correlation suggested that employees’ perceived organizational climate can influence their acceptance levels toward e-learning, which implies the importance of addressing organizational issues while integrating e-learning into workplaces in South Korea

Various temperature effects on spikelet growth in hulless oat during grain-filling stage

Temperature conditions affect growth and grain development during the grain-filling stage, but a comprehensive analysis of oat subjected to different temperatures during grain development has not been studied. In this study, an integrated physiological and proteomic examination of oat spikelets was performed to analyze the influence of five different day-time temperatures on stress-relative parameters and grain development. Physiological analysis showed decrease of total chlorophyll, shoot dry weight and spikelet shape development and increased activation of MDA, soluble sugar and antioxidant enzymes, with increase of temperatures. However, considering major grain yield components and storage materials, there should be an optimum temperature during ripening period. The result of proteomic analysis showed significantly high expressions of stress-related gene in high temperature treatment and grain storage materials in optimum temperature. Our findings indicate that temperature conditions during the grain-filling period exert a major influence on yield potential

Interaction of edge waves with swell on a beach

Excitation of edge waves on a beach by incoming swell is considered on the basis of shallow-water model. Subharmonic resonance mechanism of interaction is analyzed by multi-scaled expansion asymptotic techniques. The generation of edge waves between wave breakers is found to have a dynamic threshold. It is defined by intensity and frequency of incoming swell, geometry of a shore zone. Nonlinear no stationary wave solutions for the envelope of interacting edge waves are described by generalized Sine-Gordon model. An infinite set of exact solutions are received by the Lamb method for the phase synchronism regime of wave’s interaction

Coronavirus proteins as ion channels: Current and potential research

Coronavirus (CoV) outbreaks have recently emerged as a global public health threat due to their exceptional zoonotic potential - a feature arising from their ability to infect a diverse range of potential hosts combined with their high capacity for mutation and recombination. After Severe Acute Respiratory Syndrome (SARS) CoV-1 in 2003 and Middle East Respiratory Syndrome (MERS) CoV in 2012, with the current SARS-CoV-2 pandemic we are now in the midst of the third deadly international CoV outbreak in less than 20 years. Coronavirus outbreaks present a critical threat to global public health and an urgent necessity for therapeutic options. Here, we critically examine the current evidence for ion channel activity in CoV proteins and the potential for modulation as a therapeutic approach

Effects of Increasing Concentrations of Corn Distiller’s Dried Grains with Solubles on Chemical Composition and Nutrients Content of Egg

Four diets were formulated to contain 0, 17, 35 or 50% corn DDGS. A total of 240 54-week-old single-comb White Leghorn laying hens were assigned to one of four dietary treatments and fed for a 24-week experimental period. Two sets of the experimental diets were formulated and each diet was fed for 12 weeks. Chemical composition and nutritional components in egg yolk were measured. Egg yolk from hens fed DDGS-containing diet tended to have higher fat content and lower protein content. Total polyunsaturated fatty acids were significantly increased by DDGS diet. The contents of choline and cholesterol were initially higher in 50% DDGS treatment group, but were not different in the later period, especially during last 4 weeks. Lutein content increased linearly as DDGS level increased. The results indicated that feeding high level of DDGS can increase the content of lutein and polyunsaturated fatty acids in egg yolk, but may not affect the content of cholesterol or choline