archives@tulane.edu / 1 / Olakunle Francis Ojo

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Fluorescence (F), DCMU-enhanced fluorescence (F^DCMU) and a ratio of these two measurements (F ratio) were found to be useful indicators of light history but not physiological condition of natural phytoplankton assemblages. Changes in the fluorescence properties of unialgal continuous and batch cultures at different growth rates and following nutrient addition were observed only during nutrient starvation. Nutrient deficiency in Lake Ontario was not revealed either by seasonal patterns of fluorescence or by short term changes in the F ratio following nutrient additions. This result however is not conclusive evidence of nutrient sufficiency because of the insensitivity of the fluorescence ratio as an indicator of growth rate. The depression of F and F^DCMU observed in surface waters of Lake Ontario occurred during conditions of high light and low mixing rates. The result suggests that ''photoinhibition" of photosynthesis as measured by conventional primary productivity techniques, may occur in nature only under these particular conditions. A general relationship between temperature gradients or water column stability and the difference in fluorescence between 1 and 10 meters was observed. This relationship was due to both vertical structure in the assemblage and the physiological effect of light on fluorescence. Diurnal patterns of fluorescence were found to be due to the physiological effect of light on fluorescence rather than a circadian rhythm. The physiological effect was dependent on both the duration and intensity of exposure of the cells to light as well as the sensitivity of the assemblage to light. Differences were associated with seasonal changes in species composition with spring and winter populations exhibiting the greatest sensitivity. / Thesis / Master of Science (MSc)

Plasmonics can achieve the tight optical confinement and localization in the subwavelength domain. Surface plasmon polaritons (SPPs) are closely related to coupling to emitters in excitation and emission, waveguiding, and active modulating on the nanoscale. Due to these phenomenon, plasmonic nanostructures can be used for applications, such as light emission, photodetection, optical sensing, and spectroscopy. Conventional plasmonic nanostructures can support plasmonic modes, and it is typically optimized for a single wavelength window with planar plasmonic structures. Recent studies have reported some in-plane composite nanostructures and core-shell geometries can induce multiple plasmonic responses. However, it is challenging to achieve the control of individual plasmonic response due to the interdependent spectral tunability with changes in their in-plane geometries. In this dissertation, the concept of out-of-plane engineered nanoantenna structures is introduced, numerically calculated, and experimentally demonstrated. The nanolaminated MIM plasmonic structures show multiresonant plasmonic responses in the same antenna and each wavelength band can be tunable individually with different thicknesses of dielectric layers. The nanolaminated plasmonic structures has been reported for a scalable Surface-enhanced Raman spectroscopy (SERS) substrate for single-molecule sensitive and label-free chemical analysis. Due to the strong optical field confinement, the nanolaminated SERS substrates achieve increased SERS enhancement factor (EF) up to 1.6 x 108 with proper partial etching of dielectric layers. Furthermore, the nanolaminated MIM plasmonic structures have been successfully integrated with micro-scale pillar arrays to control the surface wettability for ultrasensitive SERS measurements. The hierarchical micro/nano plasmonic surface has densely packed intrinsic SERS-active hot spots that give rise to SERS EFs exceeding 107. This platform can take full advantage of low surface energy to control and measure the analyte in water droplets. Leidenfrost evaporation-assisted SERS sensing on the hierarchical substrates provides the way for ultrafast and ultrasensitive biochemical detections without a need for additional surface modifications and chemical treatments. / Doctor of Philosophy / The life in the 21th century has benefited from the technical revolutions of computational power that is based on the manipulation/storage of electrons. As predicted in Moore's law, the size of electronic microchip would go down, and the computational power has been enhanced due to the increase of transistor integration density. However, the two major factors, such as energy dissipation of electrons and signal delay of electronic circuit, limit the communication speed of electronics. These barriers have caused slowdown in the performance of computational power. Photonic solutions have been offered to solve the limitations based on the larger bandwidth and a rare energy dissipation, compared to electronic counterparts. Moreover, optical communications typically demand much lighter channel to deliver similar power/information than practical electrical cables do. Thus, light manipulation/enhancement techniques are envisioned to overcome the limitations and guide to the methodology of interconnections between the electronic circuits and optical platforms. Plasmonics can achieve the nanoscale light confinement and localization in the subwavelength domain. This strong confinement is originated from the coupling between the photons and the electron gas on the metal that results in surface plasmon polariton (SPP). SPPs are closely related to coupling to emitters in excitation and emission, waveguiding, and active modulating on the nanoscale. Due to these phenomenon, plasmonic nanostructures can be used for applications, such as light emission, photodetection, optical sensing, and spectroscopy. In this dissertation, the concept of out-of-plane engineered nanoantenna structures is introduced, numerically calculated, and experimentally demonstrated. This vertically stacked nanoantenna structure is composed of metal-insulator-metal (MIM) laminates fabricated by physical vapor deposition techniques. Although conventional plasmonic nanostructures can support plasmonic modes, it is typically optimized for a single wavelength window. The nanolaminated MIM nanostructures, by contrast, can induce multiresonant plasmonic response in the same antenna with several advantages: (1) reduced individual footprint size and volume of nanoantenna, (2) accurate control of layer thicknesses by thin film deposition technique for resonance tuning, (3) easier integration with other functional materials as gap layers, and (4) efficient transport of charge carriers or heat in nanolaminated layers. As a result of the tight optical field confinement, the nanolaminated plasmonic structures can be used for sensing application called Surface-enhanced Raman spectroscopy (SERS), which is a promising sensing platform for label-free biochemical analysis at the single-molecule level. Partial oxide etching process enables the analyte molecules to accommodate in strong enhancement region of the nanolaminated structures, resulting in amplified unique Raman features of molecular compounds as a finger print. The SERS enhancement factor is increased by one order of magnitude achieving 1.6x108. Furthermore, the nanolaminated plasmonic structures have been integrated with micro-scale pillar arrays to control the surface wettability for ultrasensitive SERS measurements.

During the past decade, carbon capture, utilization, and storage (CCUS) has gained considerable recognition as a viable option to mitigate carbon dioxide (CO2) emissions. This process involves capturing CO2 at emission sources such as power plants, refineries, and processing plants, and safely and permanently storing it in underground geologic formations. Many CO2 injection tests have been successfully conducted to assess the storage potential of CO2 in saline formations, oil and natural gas reservoirs, organic-rich shales, and unmineable coal reservoirs. Coal seams are an attractive reservoir for CO2 storage due to coal's large capacity to store gas within its microporous structure, as well as its ability to preferentially adsorb CO2 over naturally occurring methane resulting in enhanced coalbed methane (ECBM) recovery. A small-scale CO2 injection test was conducted in Southwest Virginia to assess the storage and ECBM recovery potential of CO2 in a coalbed methane reservoir. The goal of this test was to inject up to 20,000 tons of CO2 into a stacked coal reservoir of approximately 15-20 coal seams. Phase I of the injection test was conducted from July 2, 2015 to April 15, 2016 when a total of 10,601 tons of CO2 were injected. Phase II of the injection was conducted from December 14, 2016 to January 30, 2017 when an additional 2,662 tons of CO2 were injected, for a total of 13,263 total tons of CO2 injected. A customized monitoring, verification, and accounting (MVA) plan was created to monitor CO2 injection activities, including surface, near-surface, and subsurface technologies. As part of this MVA plan, chemical tracers were used as a tool to help track CO2 plume migration within the reservoir and determine interwell connectivity. The work presented in this dissertation will discuss the development and implementation of chemical tracers as a monitoring tool, detail wellbore-scale tests performed to characterize CO2 breakthrough and interwell connectivity, and present results from both phases of the CO2 injection test. / PHD / During the past decade, carbon capture, utilization, and storage (CCUS) has gained considerable recognition as a viable option to mitigate carbon dioxide (CO2) emissions. This process involves capturing CO2 at emission sources such as power plants, refineries, and processing plants, and safely and permanently storing it in underground geologic formations. Many CO2 injection tests have been successfully conducted to assess the storage potential of CO2 in saline formations, oil and natural gas reservoirs, organic-rich shales, and unmineable coal reservoirs. Coal seams are an attractive reservoir for CO2 storage due to coal’s large capacity to store gas within its microporous structure, as well as its ability to preferentially adsorb CO2 over naturally occurring methane resulting in enhanced coalbed methane (ECBM) recovery. A small-scale CO2 injection test was conducted in Southwest Virginia to assess the storage and ECBM recovery potential of CO2 in a coalbed methane reservoir. The goal of this test was to inject up to 20,000 tons of CO2 into a stacked coal reservoir of approximately 15-20 coal seams. Phase I of the injection test was conducted from July 2, 2015 to April 15, 2016 when a total of 10,601 tons of CO2 were injected. Phase II of the injection was conducted from December 14, 2016 to January 30, 2017 when an additional 2,662 tons of CO2 were injected, for a total of 13,263 total tons of CO2 injected. A customized monitoring, verification, and accounting (MVA) plan was created to monitor CO2 injection activities, including surface, near-surface, and subsurface technologies. As part of this MVA plan, chemical tracers were used as a tool to help track CO2 plume migration within the reservoir and determine interwell connectivity. The work presented in this dissertation will discuss the development and implementation of chemical tracers as a monitoring tool, detail wellbore-scale tests performed to characterize CO2 breakthrough and interwell connectivity, and present results from both phases of the CO2 injection test.

Glioblastoma is a deadly brain cancer with discouraging standard of care. New methods like convection enhanced delivery and chimeric antigen receptor T cells (CAR-T) are promising treatments that can be translated to glioblastoma. In this study, CAR-T cell flow through a hydrogel was explored in the context of in-vitro convection enhanced delivery. A culture method to create large spheroids mimicking tumors from preexisting glioblastoma stem cell lines was fabricated, a convection enhanced delivery system for in-vitro testing was designed, and characterization of the CAR-T cells using the in-vitro system took place. The spheroid culture method was successfully optimized to produce spheroids large enough to act as a sufficient tumor in little time, the in-vitro set-up successfully administered treatment, and CAR-T cells were found to increase their velocities through a medium as their injection velocity increased. It was discovered that the density of the spheroid plays a crucial role in treatment delivery, often times driving how treatment will move through the spheroid. This system can be used in the future studies to test the killing potential of CAR-T cells to a tumor in-vitro. / Master of Science / Glioblastoma is a deadly brain cancer with current treatments that are discouraging at best. New methods must be utilized to aid in patient recovery. Chimeric antigen receptor T-Cells (CAR-T) are a promising treatment that can be used in glioblastoma. In this study, CAR-T cell behavior is defined in the context of in-vitro convection enhanced delivery. A large spheroid, or sphere of cells, mimicking a tumor was created, a convection enhanced delivery system set-up for in-vitro testing was designed, and characterization of CAR-T cell behavior using the in-vitro system took place. The spheroids were successfully cultured to act as a sufficient tumor, the in-vitro set-up successfully administered treatment, and CAR-T cells were found to increase their velocities in a gel as their injection velocity increases. It was discovered that the density of the spheroid plays a crucial role in treatment delivery, often times driving how treatment will move through the spheroid. This system can be used in the future studies to test the killing potential of CAR-T cells to a tumor in-vitro.

Institutions are looking to find the best learning technologies to deliver anatomy curricula to diverse student populations, often working with financial and time-based constraints. Visualization techniques, particularly the widespread use of virtual reality headsets, have made once-impossible learning experiences possible. This thesis explores the effect of different learning modalities (virtual reality headset, computer screen, and 3D-printed models) and environments (clinical context or context-free) on knowledge acquisition and learning experiences for a pelvic floor anatomy module. We investigated how these factors, along with mental rotation ability and stereoacuity, impact various aspects of learning, including performance on anatomy tests, perceived workload (measured using the NASA Task Load Index), cybersickness (measured using the Simulator Sickness Questionnaire), and engagement during learning (measured using the User Engagement Scale). Significant interactions were found between modality and environment for test scores and workload, a significant main effect of modality and environment for cybersickness, and a significant main effect of modality for engagement. Importantly, though significant differences were found between modalities and environments, participants reported concerningly high levels of workload and cybersickness across all conditions. High levels of engagement were also reported across all learning conditions. The lack of meaningful differences between intervention groups emphasizes the importance of curricular design over the implementation of new technologies and the need to be critical of the impression that a one-size-fits-all solution exists. Theories of cognitive load, constructivism, syncretion, visuospatial ability, cybersickness, and embodied learning in the context of technology-enhanced anatomy education are discussed as the foundation upon which design decisions should be made. A multi-faceted approach focused on aligning learning objectives with learning activities is outlined as a means of driving more impactful research and improving anatomy education. / Thesis / Master of Science (MSc) / Institutions are looking to find the best learning technologies to deliver anatomy curricula to diverse student populations, often working with financial and time-based constraints. Visualization techniques have been at the forefront of this innovation, and the widespread use of virtual reality headsets has made once-impossible learning experiences achievable. This thesis explores the effect of different learning modalities and environments on learning with a pelvic floor anatomy module. We investigated how these factors, along with mental rotation ability and stereoacuity impact test performance and the perception of workload, cybersickness, and engagement. The results emphasize the importance of curricular design over the implementation of new technologies and the need to be critical of the impression that a one-size-fits-all solution exists.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / As the size of missiles and UAVs shrink, so does the volume available for the Flight Termination System (FTS). Small, light weight FTS systems open up applications not possible with the larger and heavier conventional FTS systems. This paper presents a novel approach for the design, implementation and test of a subminiature Flight Terminate System Receiver for use in the Subminiature Flight Safety System (SFSS). This receiver implements the new digital-based Enhanced Flight Termination System (EFTS) protocol, while maintaining a volume of less than 1 cubic inch with power consumption of less than 2 watts. Combining all of the necessary functionality into a small package while meeting the rigorous requirements of the Range Commanders Council (RCC) specifications (EMI, vibration and shock) presented significant challenges. The Subminiature Enhanced Flight Termination Receiver used in the SFSS has been named the "SEFTR".