Concerns about increased stratospheric ozone depletion increasing ambient levels of ultraviolet-B radiation (UV-B), and the fact that some ecosystems are naturally exposed to high levels, has resulted in an increased interest in the effects of UV-B on plant communities. Despite this, there has been a paucity of studies into its effects on plant competition. Artificial plant communities consisting of Lolium perenne and Lotus corniculatus and a sub-montane community consisting of Agrostis tenuis, Festuca ovina and Galium saxatile (also including different nitrogen levels) were created using the response surface approach. The long-term effects of UV-B were also studied on a natural sub-Arctic community in Abisko, Sweden. In addition, all plant samples were analysed by Fourier-Transform Infrared Spectroscopy (FT-IR) to obtain a ‘metabolic fingerprint’ which was used to detect chemical differences to the whole biochemical complement of the sample. The results showed that enhanced UV-B altered the competitive interaction of Lolium perenne and Lotus corniculatus in favour of Lolium perenne although ambient levels of UV-B did not elicit an effect in the sub-montane community. Only one dwarf shrub species in the sub-Arctic experiment, Vaccinium myrtillus, was negatively affected by UV-B. In most cases, elevated UV-B elicited a change in the metabolic fingerprint in the samples and in some cases an alteration in competitive stress altered the metabolome. This suggests that FT-IR can be used as a screening tool to detect for both abiotic stress and competitive biochemical alterations. In addition, this thesis proposes that the facilitative effect between the grass-legume mixture of Lolium perenne and Lotus corniculatus is not related to nitrogen fixation in the early stages of competition which has traditionally been believed.

Remediation of heavy metals from industrial effluents and ground water sources poses a significant challenge. Hexavalent chromium is one such heavy metal, prevalent in industrial wastewaters, which has been proven to be toxic to humans and other living organisms. Most of the conventional methods available for dealing with chromium are either cost prohibitive or generate secondary effluents which are difficult to deal with. The idea of bioremediation has gained much momentum over the last few decades because of its potential low cost and minimum impact on the environment. This study explored the potential for hexavalent chromium bioremediation using a synthetic cationic biopolymer alpha-poly-l-lysine (alpha-PLL) as a biosorbent. In the present research work, equilibrium batch studies were performed in a specially designed dialysis apparatus to obtain preliminary information about the adsorption capacity of the polymer. Metal uptake by the polymer was found to be maximum when the pH of chromium solution (pH 4.6) and that of poly-lysine (pH 5.7) was not changed at the beginning of the experiment. Applying the Langmuir adsorption isotherm model showed that alpha-PLL has a maximum uptake capacity of 42.2 microgram Cr/mg alpha-PLL, and a binding constant of 1.2 microgram/mL +/- 10%. The metal uptake performance of the polymer was also evaluated in a Polymer Enhanced Diafiltration (PEDF) system. The polymer-metal complex was retained and concentrated by the PEDF set up using a tangential flow filtration membrane, while the clean filtrate flowed through. When 3.4 L of 10 mg/L chromium solution in the Cr2O72- form was processed using 300 mL of 2 gm/L PLL, the concentration of chromium in the permeate reached a maximum of 0.79 mg/L. When 30 mg/L chromium solution was used, 2 L could be processed using 300 mL of 2gm/L PLL, and 7.8 mg/L chromium could be detected in the permeate in the end.

While the last century of medical discoveries has made a significant impact on improving the lives of human populations across the globe, a perfect solution to the yearly infection cycle from the influenza virus has yet to be discovered. Although vaccines stand the best chance at targeting yearly epidemics, new treatment options must be created to combat the arrival of rapidly mutating and antiviral-resistant strains of the virus that could lead to another pandemic such as the 1918 Spanish flu that killed millions worldwide. We describe a method to create functionally enhanced monoclonal antibodies targeting influenza via genetic engineering of fragment crystallizable glycan structures. Muscle and liver cell lines were lentivirally-transduced to produce the broadly neutralizing antibody, Fi6v3, while also overexpressing a critical glycosylation enzyme, B-1,4-N-acetyl-glucosaminyltransferase III. Secreted antibodies were tested for effector functionality using a Natural Killer cell degranulation assay and an antibody-dependent cellular phagocytosis assay. Results conclude that modified antibodies from both muscle and liver cells lines exhibit enhanced function in comparison to their unmodified counterparts, providing support to the future creation of an influenza prophylactic or treatment option using antibodies with the ability to more effectively activate innate immune killing mechanisms.

A new molecular imaging modality has been developed to detect and locate positive axillary and sentinel lymph nodes non-invasively in breast cancer patients undergoing lymphoscintigraphy. The modality is based on fluorescent photon detection to locate the presence of indocyanine green (ICG) in the lymph subsequent to peritumoral injection of ICG into the breast. The imaging system consists of a gain-modulated intensified charge-coupled device (ICCD) camera, which captures low-intensity, near-infrared, and frequency-modulated photons. A four-fold ‘optical lymphography’ study was conducted to (1) examine fluorescence depth penetration and ICCD system accuracy at clinically relevant depths, (2) compare image quality of the ICCD system vs. conventional gamma imaging, (3) measure ICG pharmacokinetics in vivo, and (4) develop a clinical protocol while examining pre-clinical factors such as the outcome of combining ICG with sulfur colloids used in lymphoscintigraphy. The frequency-domain ICCD system was found to precisely detect modulation amplitude, IAC, and phase, θ, at depths up to 9 cm and with IAC accuracy less than 20% and θ less than 2º using an 80-mW laser incident on phantoms having ranging tissue optical properties. Significant differences in the mean depth of penetration owing to 0.62-ns lifetime and 100-MHz frequency increases were detected. An in vivo optical vs. nuclear image quality comparison demonstrated statistically similar (α=0.05) target-to-background ratios for optical (1.4+/-0.3) and nuclear (1.5+/-0.2). Alternatively, resulting image signal-to-noise ratios (SNR) from the ICCD system were greater than that achieved with a conventional gamma camera (pvalue<<0.01). Analysis of SNR versus contrast showed greater sensitivity of optical over nuclear imaging for subcutaneous tumors. In vivo and rapid detection of ICG in the blood-stream of nude mice was accomplished with a home-built avalanche photodiode dynamic fluorescence measurement system. Intensity data upon i.v. injection were regressed with a pharmacokinetic model describing the partitioning of ICG from the blood to the surrounding tissues. ICG blood-clearance was detected approximately 15 min after injection. Lastly, a human subject protocol was written, practiced, and federally approved for the application of optical lymphography. Furthermore, ICG was unaffected when mixed with sulfur colloids thus supporting the feasibility for combining fluorescence imaging with lymphoscintigraphy in breast cancer patients.

At the heart of the field of photonics is the control of the reflection and transmission of light. Plasmonics looks at this problem of control of electromagnetic radiation in the context of surface plasmon polaritons (SPP). SPPs are propagating electromagnetic modes localized at the interfaces between media with positive and negative permittivities. Their excitation can accompany the enhancement of transmission, reflection, or absorption of EM radiation. There are a number of ways to excite SPPs and this work looks at several geometries and analyzes the transmission and reflection characteristics using a numerical approach based on the finite element method.<p> The first method of excitation is by incident evanescent wave that was totally internally reflected from an earlier interface. It is shown that an evanescent wave can excite SPPs and create resonant transmisison. It is also found that high values of dissipation limit transmission and instead create resonant absorption. The second method involves the modulation of the negative permittivity of the plasma slab itself. Numerical results are compared to analytical ones and are in good agreement because harmonics of the solution above the first are negligible. An investigation of transmission through a plasma slab with a single thin diffraction grating placed nearby follows. Analytical and numerical calculations show that a single thin grating is sufficient to create transmission resonance. It is found that for large values of diffraction grating modulation parameter, higher harmonics, usually not accounted for in analytical solutions, results in discrepancies between analytical and numerical results. The next geometry considered is of a plasma layer with only part of it having modulated permittivity. The presence of modulation of only part of the plasma layer is shown to create transmission and reflection resonances. By tailoring parameters of the system, it is shown how the resonant frequencies can be shifted. The final geometry considers a copper grating beside a plasma and transmission of a radio frequency wave. Even though the copper used here in this simulation is very absorbing, there are ranges of frequencies when transmission or reflection are enhanced.

At the heart of the field of photonics is the control of the reflection and transmission of light. Plasmonics looks at this problem of control of electromagnetic radiation in the context of surface plasmon polaritons (SPP). SPPs are propagating electromagnetic modes localized at the interfaces between media with positive and negative permittivities. Their excitation can accompany the enhancement of transmission, reflection, or absorption of EM radiation. There are a number of ways to excite SPPs and this work looks at several geometries and analyzes the transmission and reflection characteristics using a numerical approach based on the finite element method.<p> The first method of excitation is by incident evanescent wave that was totally internally reflected from an earlier interface. It is shown that an evanescent wave can excite SPPs and create resonant transmisison. It is also found that high values of dissipation limit transmission and instead create resonant absorption. The second method involves the modulation of the negative permittivity of the plasma slab itself. Numerical results are compared to analytical ones and are in good agreement because harmonics of the solution above the first are negligible. An investigation of transmission through a plasma slab with a single thin diffraction grating placed nearby follows. Analytical and numerical calculations show that a single thin grating is sufficient to create transmission resonance. It is found that for large values of diffraction grating modulation parameter, higher harmonics, usually not accounted for in analytical solutions, results in discrepancies between analytical and numerical results. The next geometry considered is of a plasma layer with only part of it having modulated permittivity. The presence of modulation of only part of the plasma layer is shown to create transmission and reflection resonances. By tailoring parameters of the system, it is shown how the resonant frequencies can be shifted. The final geometry considers a copper grating beside a plasma and transmission of a radio frequency wave. Even though the copper used here in this simulation is very absorbing, there are ranges of frequencies when transmission or reflection are enhanced.

CO2 has been widely used as a displacement fluid in both immiscible and miscible displacement processes to obtain tertiary recovery from the field. There are several problems associated with the application of CO2 flooding, especially when there is a significant presence of heterogeneous elements, such as fractures, channels and high permeability streaks within the reservoir. With flooding, CO2 will finger through the target zone while leaving most of the residual/trapped oil untouched. As a result, early gas breakthrough has been a very common problem in CO2-related projects, reducing the overall sweep efficiency of CO2 flooding. This research aims at improving the CO2 flood efficiency using cross-linked gel conformance control and CO2 viscosifier technique. A series of coreflood experiment studies have been performed to investigate the possibility of applying CO2 mobility control techniques. Corresponding simulation works have also been carried out to predict the benefits of applying CO2 mobility control techniques in the field. In the laboratory study, the CO2 coreflood system was integrated with the CT (Computed Tomography)-scanner and obtained real-time coreflood images of the CO2 saturation distributions in the core. This system was applied to the research of both cross-linked polymer gel treatment and CO2 viscosifier study and produced images with sharp phase contrasts. For the gel conformance study, promising results were obtained by applying cross-linked gel to eliminate permeability contrast and diverting CO2 into low permeability regions to obtain incremental oil recovery; also studied were the gel strength in terms of leak-off extent with the aid of CT (Computed Tomography) images. For the CO2 viscosifier research, we tested several potential viscosifier chemicals and found out PVAc (Polyvinylacetate)/toluene combination to be the most promising. The follow-up study clearly demonstrates the superiority of viscosified CO2 over neat CO2 in terms of sweep efficiency. This research serves as a preliminary study in understanding advanced CO2 mobility control techniques and will provide insights to future studies on this topic.

Carbon dioxide (CO2) from energy consumption is a primary source of greenhouse gases. Injection of CO2 from power plants in coalbed reservoirs is a plausible method for reducing atmospheric emissions, and it can have the additional benefit of enhancing methane recovery from coal. Most previous studies have evaluated the merits of CO2 disposal in high-rank coals. Low-rank coals in the Gulf Coastal plain, specifically in Texas, are possible targets for CO2 sequestration and enhanced methane production. This research determines the technical feasibility of CO2 sequestration in Texas low-rank coals in the Wilcox Group in east-central Texas and the potential for enhanced coalbed methane (ECBM) recovery as an added benefit of sequestration. It includes deterministic and probabilistic simulation studies and evaluates both CO2 and flue gas injection scenarios. Probabilistic simulation results of 100% CO2 injection in an 80-acre 5-spot pattern indicate that these coals with average net thickness of 20 ft can store 1.27 to 2.25 Bcf of CO2 at depths of 6,200 ft, with an ECBM recovery of 0.48 to 0.85 Bcf. Simulation results of 50% CO2 - 50% N2 injection in the same 80-acre 5-spot pattern indicate that these coals can store 0.86 to 1.52 Bcf of CO2, with an ECBM recovery of 0.62 to 1.10 Bcf. Simulation results of flue gas injection (87% N2 - 13% CO2) indicate that these same coals can store 0.34 to 0.59 Bcf of CO2, with an ECBM recovery of 0.68 to 1.20 Bcf. Methane resources and CO2 sequestration potential of low-rank coals of the Wilcox Group Lower Calvert Bluff (LCB) formation in east-central Texas are significant. Resources from LCB low-rank coals in the Wilcox Group in east-central Texas are estimated to be between 6.3 and 13.6 Tcf of methane, with a potential sequestration capacity of 1,570 to 2,690 million tons of CO2. Sequestration capacity of the LCB lowrank coals in the Wilcox Group in east-central Texas equates to be between 34 and 59 years of emissions from six power plants in this area. These technical results, combined with attractive economic conditions and close proximity of many CO2 point sources near unmineable coalbeds, could generate significant projects for CO2 sequestration and ECBM production in Texas low-rank coals.

A new molecular imaging modality has been developed to detect and locate positive axillary and sentinel lymph nodes non-invasively in breast cancer patients undergoing lymphoscintigraphy. The modality is based on fluorescent photon detection to locate the presence of indocyanine green (ICG) in the lymph subsequent to peritumoral injection of ICG into the breast. The imaging system consists of a gain-modulated intensified charge-coupled device (ICCD) camera, which captures low-intensity, near-infrared, and frequency-modulated photons. A four-fold ‘optical lymphography’ study was conducted to (1) examine fluorescence depth penetration and ICCD system accuracy at clinically relevant depths, (2) compare image quality of the ICCD system vs. conventional gamma imaging, (3) measure ICG pharmacokinetics in vivo, and (4) develop a clinical protocol while examining pre-clinical factors such as the outcome of combining ICG with sulfur colloids used in lymphoscintigraphy. The frequency-domain ICCD system was found to precisely detect modulation amplitude, IAC, and phase, θ, at depths up to 9 cm and with IAC accuracy less than 20% and θ less than 2º using an 80-mW laser incident on phantoms having ranging tissue optical properties. Significant differences in the mean depth of penetration owing to 0.62-ns lifetime and 100-MHz frequency increases were detected. An in vivo optical vs. nuclear image quality comparison demonstrated statistically similar (α=0.05) target-to-background ratios for optical (1.4+/-0.3) and nuclear (1.5+/-0.2). Alternatively, resulting image signal-to-noise ratios (SNR) from the ICCD system were greater than that achieved with a conventional gamma camera (pvalue<<0.01). Analysis of SNR versus contrast showed greater sensitivity of optical over nuclear imaging for subcutaneous tumors. In vivo and rapid detection of ICG in the blood-stream of nude mice was accomplished with a home-built avalanche photodiode dynamic fluorescence measurement system. Intensity data upon i.v. injection were regressed with a pharmacokinetic model describing the partitioning of ICG from the blood to the surrounding tissues. ICG blood-clearance was detected approximately 15 min after injection. Lastly, a human subject protocol was written, practiced, and federally approved for the application of optical lymphography. Furthermore, ICG was unaffected when mixed with sulfur colloids thus supporting the feasibility for combining fluorescence imaging with lymphoscintigraphy in breast cancer patients.

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xiii, 139 p. : ill. Vita. Includes abstract. Includes bibliographical references.