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This thesis presents an experimental study of a novel non-thermal atmospheric-pressure gas plasma with controlled liquid droplet flow as an efficient source of reactive species that can influence fundamental chemistries in many applications. The electrical discharge is ignited within the confined geometry of a cylindrical quartz tube that allowed for small liquid droplets entrained in the gas flow to pass through the plasma region only once. Neon was used to generate the droplets from deionised water or a buffered solution and additional helium transported the droplets from the nebuliser through the plasma. A diffuse, glow-like discharge formed that remained ignited during droplet transport. Droplets that enter the plasma contribute to the formation of reactive species and survive the treatment without complete evaporation. This observation paved the way for attempts to expose bacteria-loaded droplets to the same treatment. When collected in the presence of a hydrogen peroxide scavenger, plasma treatment did not affect cell viability or growth kinetics. A biomarker of lipid peroxidation was detected, suggesting cell interaction with plasma-generated species delivered into the droplet over short timescales i.e. droplet transit time through the plasma region. Due to the omission of oxygen and nitrogen from the plasma, a vast proportion of RONS that are reported in the plasma-liquid literature cannot be generated, therefore simplifying the chemistry. Hydroxyl radical is thought to feature in the onset of cellular oxidative stress and the species is known to be generated from plasma-liquid interactions. The radical was detected in both the gas and liquid phases from the plasma treatment of droplets and remained chemically active far from the core plasma region. Hydrogen peroxide is a well-known biocide generated from plasma-liquid interactions and was detected in the plasma-treated droplet collection liquid. These results suggest the new technique can remotely apply reactive species contained in plasma-activated droplets or bulk liquid to a target that never comes in direct contact with the plasma itself. This has the potential to be able to influence biological systems in a controlled way by fine-tuning the chemistry generated from the interaction between non-equilibrium plasma and low volume liquid droplets.

Metabolites produced by microalgae profoundly affect the natural environment as the dominant organic carbon source in the ocean and the dominant organic sulfur source to the atmosphere. Of particular interest to this dissertation is the production of algal metabolites in response to changes in organism health and biological community turnover. In this dissertation, algal metabolites are investigated in highly complex marine and in controlled commercial-oriented environments. Measurements of organosulfur gases dimethyl sulfide, methanethiol, and dimethyl disulfide during marine mesocosm experiments show that the production of highly reactive non-dimethyl sulfide organosulfur compounds can comprise a far larger fraction of total sulfur released from the ocean than previously understood. This production was found to depend on the bacterial assemblages present in each mesocosm in combination with the biochemistry of the water. To more accurately measure algal metabolites in the natural environment, a new ionization method for high resolution mass spectrometry of high-salt organic samples was applied to analysis of marine samples. This method demonstrated the ability to analyze unprocessed seawater for the first time. To produce systems which replicate the turnover of natural marine algae, a review of the ocean-atmosphere simulator approach is given. As an exemplar of this approach, an intensive experiment utilizing an ocean atmosphere simulator is given which discusses the system performance and mesocosm characteristics. As microalgae are increasingly used commercially as a source of renewable biomass, understanding the production of metabolites in response to deleterious factors such as grazing is needed. The connection between algal grazing and production of grazing-specific metabolites was investigated by combining the results from imaging mass spectrometry, liquid chromatography mass spectrometry, and gas chromatography mass spectrometry. These studies found chlorophyll-a related breakdown products in the solid and liquid phases which were connected to measurements of volatile gases. Continuous measurements of volatile gases from microalgae by chemical ionization mass spectrometry were performed to understand the timescale in which gas production in response to grazing occurs. Chemical ionization mass spectrometry was found to be able to detect grazing in algal cultures 24-72 hours faster than current best methods, opening a new monitoring approach for commercial microalgae.

BACKGROUND: Implants have been widely used in the medical field. It was adopted in dentistry, offering patients replacement of missing teeth. Researchers have been investigating techniques to improve implants’ survival. Among these techniques is plasma glow discharge. Radio-frequency Glow discharge (RGD) is a surface treatment and sterilization technique with the aim to improve the titanium oxide layer for better osseointegration. Previous studies have evaluated its effect on non-human cell lines with promising results. Up to date, there is no report on how RGD surface treatment of titanium affects normal human osteoblasts. MATERIAL AND METHODS: Human bone fragments were obtained from dental extraction sites and were processed to culture normal human osteoblasts. Cells were seeded on three different surfaces at a concentration of 1x105 cells per plate; Titanium discs with and without Argon RGD (ARGD), and tissue culture plates (TCP). Dishes were allocated to 3 timelines: 16 hours, 7 days and 14 days. The outcome measures were cell attachment, cell number, alkaline phosphatase and osteocalcin levels. RESULTS: Data was analyzed using a one-way ANOVA test. Mean cell proliferation percentage for the ARGD group at 7 days was the highest (167.966%). The difference in means among the three groups at 7 days was statistically significant (p=0.0022). At 14 days, the highest mean of cell proliferation percentage was highest for the ARGD group. When testing all pairs, at 7 days the differences in means were statistically significant between (ARGD vs. no ARGD, and ARGD vs. TCP) (p=0.0018, and p=0.0286), respectively. At 14 days, the differences in means were statistically significant between (ARGD vs. TCP, p= 0.0003) and (no ARGD vs. TCP, p=0.0007). There was a significant difference in means for alkaline phosphatase and osteocalcin at 7 and 14 days between TCP and ARGD, and TCP and no ARGD groups (p < 0.05). CONCLUSIONS: The results of this study on normal human osteoblasts indicated that ARGD significantly enhanced cell proliferation. There was no significant difference in osteogenic behavior between with and without ARGD treatment on titanium surfaces within the time studied. A prolonged phase of cell proliferation was observed in ARGD treated groups.

Metallomics is a growing field of interdisciplinary research that investigates metals in biological and environmental systems. One of the major problems in detecting metals in biological systems is the instrumentation required to analyze these complex biological samples. Typically, an inductively coupled plasma-optical emission spectrometer or -mass spectrometer (ICP - OES or - MS) is used for elemental analysis and an electrospray ionization-mass spectrometer (ESI-MS) is used for molecular information. In almost all cases, the sample introduction matrix is different for each instrument, which can affect the physiological conditions of the sample and change its properties. Particle beam/hollow cathode-optical emission spectroscopy (PB/HC-OES) and liquid chromatography-particle beam/glow discharge mass spectrometry (LC-PB/GDMS) are presented as tools for obtaining both elemental and molecular species information without changing sample preparation. The PB/HC system was coupled to a high resolution Jobin-Yvon polychromator and optimized with respect to operational parameters using a metal mixture of Ag, Ni, and Pb to display the ability of the PB/HC-OES system as a simultaneous multiple element detector. Additionally, a commercially available Hewlett Packard 5973 gas chromatography-mass spectrometer (GC-MS) was converted to a LC-PB/GDMS capable of providing comprehensive speciation (both atomic and molecular) information. The PB/HC-OES method is presented as a tool for determining metal binding characteristics involving Tf. Transferrin (Tf) is an iron transport protein that is essential for cellular survival, providing Fe3+ to cells via receptor mediated endocytosis. Transferrin is ~ 40 % Fe3+-loaded, leaving roughly 60 % of Tf with free binding sites that can potentially bind other metal ions. Validation of the PB/HC-OES method for quantitative analysis was provided by comparing loading percentages of Fe3+ into apo-Tf with UV-VIS absorbance measurements. The PB/HC-OES method was used to determine metal loading of Ni2+ and Zn2+ into the C- and N-lobes of apo-Tf and binding of Ag+ to the surface methionines of Tf. The monitoring of Cr3+ loading into apo-Tf by PB/HC-OES and ICP-OES/UV-VIS absorbance methods are presented as further validation for the use of the PB/HC-OES method. Finally, the PB/HC-OES method was used to monitor the direct metal (Fe3+, Cr3+, and Ni2+) competition for transferrin binding under physiological relevant concentrations.

A validation study was performed on a capacitively coupled argon discharge to determine the most suitable models for chemistry and electron transport. Chemical reaction rate and electron transport models choices include equilibrium or non-equilibrium electron EDFs. Experimental studies performed by our collaborative partners in the Colorado School of Mines. Conditions for the studies are 138, 315, and 618 mTorr where the cycle averaged power varied at 20, 50, and 80 Watts in which the voltage supply was driven at 13.56 MHz. Simulations were performed using pressures and voltage used in experiments. The most accurate case was for 138 mTorr at 50 Watts using a non-Maxwellian EDF based chemistry (called Bolsig+ chemistry) and a constant electron momentum transfer cross section of 20 Angstroms which was computed from Boeuf’s paper; this model accurately modeled power deposition to within 2.6%. Furthermore, species number densities, electron temperature, and sheath thicknesses are obtained. Using Bolsig+ chemistry resulted in 20,000K higher electron temperatures than using Arrhenius chemistry rates. Results indicate that power deposition occurs due to electrons gaining energy from the sheath which in turn bombard neutral species producing metastable argon.

The dietary supplement industry has expanded and many of these supplements have become an important aspect of people's everyday lives. In 1994, the U.S. Dietary Supplement Health and Education Act (DSHEA) classified numerous nutraceutical/botanical products as dietary supplements because of their beneficial medicinal properties and provided the necessary regulation to the supplement producers. Since then, the interest of the scientific community towards dietary supplements has grown intensively and numerous studies have been carried out in order to understand the chemical behavior of the active molecules in the human body. The development towards analytical methods for the quantification of the active components and adulterants in the botanical products has acquired great interest. Presented here is the chemical characterization of botanical products via a liquid chromatography particle beam mass spectrometry (LC-PB/MS) technique with dual ionization sources (electron ionization (EI) and glow discharge (GD)). More specifically, the catechin species in green tea and the caffeic acid derivatives in echinacea extracts have been characterized. As well, an arsenic speciation study was performed for the kelp and bladderwrack extract. Validation of the LC-PB/MS system was accomplished by the analysis of the ephedrine alkaloids using ephedra-containing dietary supplement standard reference materials (SRM's) 3241 Ephedra Sinica Stapf Native Extract and 3242 Ephedra Sinica Stapf Commercial Extract from NIST. Once validated, this analytical tool was applied to the separation and characterization of green tea species in the NIST green tea SRM's which are under development. Finally, a selenium speciation method is applied to selenium enriched yeast and urine samples via LC-PB/EIMS. Chromatographic methods (reversed-phase and ion-exchange) were developed and monitored by UV-absorbance and mass spectrometry. The GD source provides EI-like molecular fragmentation of each eluting compound. Therefore, a comparison between EI and GD sources can be carried out to contrast the mass spectra obtained. Quantification of the species is achieved by standard addition and internal standard approaches. Limits of detection in the nanogram level were obtained for the targeted species.

The goal of this project is to develop a physically based model suitable for feedback controller design of Reactive Ion Etch (RIE) systems. In this thesis, a phenomenological approach towards modeling the plasma generation component of the RIE process is investigated. The plasma generation component of RIE includes the physics of the plasma and chemical reactions occurring in the gas phase of the reactor. Simplified RF glow discharge models are used to describe the physics of the plasma. A simplified 1-dimensional glow discharge model with ion matrix sheaths for RIE systems with unequal electrode areas was demonstrated for the first time. A unique pressure dependent RF sheath model for asymmetric (unequal area) electrode systems has been developed. A Continuously Stirred Tank Reactor (CSTR) model is used to describe the chemical kinetics in the gas phase of the reactor. Tuned RF Langmuir probe measurements made on the Gaseous Electronics Conference (GEC) reference cell were used to validate the glow discharge and sheath models. The modeled values of discharge current, dc bias, and electron density agree well with experiments. However, the calculated discharge power for the asymmetric model with ion matrix sheaths, and trends with pressure of the electron density and temperature for the symmetric glow discharge model, do not match experimental data. The plasma generation model has been used to develop a controller for the real-time control of an Applied Materials 8300 etch tool. In other work, the ion flux to the water estimated from RF probe measurements via a physical model, has also been used to control the etch rate in real-time. Both approaches have demonstrated that controllers designed using physically based models can be used to control etch rate in real-time.