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The activity of PEA3, a member of the Ets proto-oncogene family of transcription factors, is associated with various normal and aberrant developmental processes. PEA3 is believed to function in vivo as a transcription factor which regulates the gene expression of its cellular targets. In particular, PEA3 motifs are found in the regulatory regions of several genes implicated in tumor progression and metastasis. Aberrant PEA3 activity has been linked to the development and progression of several types of cancer, particularly, breast cancer and Ewing's sarcoma. To assist in the understanding of the role that PEA3 plays in these processes, constitutively-activated alleles of PEA3 were created by fusing a segment of the EWS gene to murine PEA3; to essentially mimic the EWS-Ets fusion proteins isolated from the human cancer syndrome, Ewing's sarcoma. Five EWS-PEA3 chimeric genes were constructed and one (EWSΔN268PEA3), is an exact murine version of an EWS-human PEA3 fusion gene isolated from Ewing's sarcoma. Transcriptional analysis of the EWS-PEA3 chimeras revealed that with the exception of one mutant, all the chimeras possessed increased transcriptional activity in comparison to normal PEA3 . Furthermore, it was suggested that the transcriptional activity of the chimeras may be regulated by Ras, although this observation requires additional validation. The chimeras were not found to possess any transforming activity, however, this finding does not suggest that the chimeras are not oncogenic in nature. In conclusion, these findings suggest that the EWS-PEA3 chimeras may indeed function as activated versions of the PEA3 transcription factor. / Thesis / Master of Science (MS)

The repair of damaged or diseased bone tissue often requires the use of metallic implants which form an interface with the surrounding bone tissue. Understanding this interface is important for improving the outcomes of implant placement and overall health of patients. Bone is a composite material of organic collagen fibrils and inorganic mineral phases that have structural variations across multiple length scales. This heterogeneous and hierarchical nature poses characterization challenges for (i) understanding bone, (ii) creating biomaterial structures that mimic it, and (iii) approaches for evaluating biomaterials. These challenges formed the basis for the three papers presented in this thesis. In Chapter 3, leporine bone was examined using atom probe tomography (APT) to visualize in vivo mineralized collagen fibrils, their chemical composition, and spatial arrangement in 3D with sub-nanometer accuracy. This provided new insight into the location of biomineral with respect to collagen and demonstrated the power of APT for understanding collagen-mineral arrangement. In Chapter 4, commercially pure titanium was laser ablated to generate periodic surface structures inspired by the periodicity of collagen. Three different periodicities were generated with submicron-scale roughness and a high degree of reproducibility. All the surfaces were non-cytotoxic and encouraged cells to adhere perpendicular to the orientation of the surface structures. In Chapter 5, a simple five-minute room temperature ionic liquid treatment was developed to investigate the same laser-ablated titanium periodic structures with osteoblast-like cells adhered. The development of this technique fulfills an important niche in biological imaging by allowing for simultaneous and repeated visualization of submicron surface features and wet cells. Therefore, the combined impact of this thesis is novel imaging and biomaterials evaluation strategies to (i) improve understanding of bone structure; (ii) leading to bioinspired biomaterials design; and (iii) new methods for simultaneous biological and biomaterials evaluation. / Thesis / Doctor of Philosophy (PhD) / Bone implant devices are required to treat, augment, or replace bone tissue in dental and orthopaedic applications. These, often metallic, implanted devices have success when a structural and functional connection with natural bone tissue is created, a phenomenon known as osseointegration. Good osseointegration is required to ensure stability of the implant without compromising the quality of life of the patient. In order to improve osseointegration of biomaterials, both sides of the interface, i.e. the bone and implant surface, must be better understood. This thesis focuses on exploring methods to improve the evaluation and understanding of both bone structure at the nanoscale and structured metallic implant surfaces for the design of bone-interfacing biomaterials.

Abstract Heavy metals are used in many industrial processes and their cations are either valuable or environmentally harmful to discharge in wastewater. Thus, it is necessary to separate heavy metals in wastewater treatment. Amongst several technical methods of separation, use of permeable membranes is an important one. For separation processes, membranes can be selective towards a target heavy metal cation either against mono-valent common cations or against other similar heavy metal cations. Synthesis of selective permeable membranes for separation purposes is an area of continuous research to meet specific needs in different applications. One of the common applications of selective separation by a permeable membrane is cation/anion separation processes using cation exchange and anion exchange membranes. Another application of selective permeable membranes is the separation of mono-valent cations from other higher valence cations. Some researchers have focused on specific selective separation of heavy metal cation from other heavy metal cations having the same valent charge. Some use chelating particulates dispersed in a neutral polymeric membrane matrix and others applied a thin chelating film on the surface of a commercial cation exchange membrane. In this work, the synthesis of novel permeable selective membranes and their use for selective separation between two di-valent heavy metal cations is presented. Three different sets of membranes were prepared in non-imprinted and imprinted forms. The ion imprinted membranes form is prepared by pre-reacting the target metal ion with the selective chelating monomer before applying in situ polymerization step, and in the non-imprinted membranes form this step is not considered. Their morphological and chemical structures were determined and their separation performances were investigated using a diffusion dialysis technique. The first membrane (non-imprinted polyvinylidene fluoride-divinylbenzyl-triethylenetetramine (PVDF/diVB-TETA) and Cu-imprinted PVDF/diVB-TETA-Cu forms) was prepared by in situ polymerization of the chelating monomer divinylbenzyl-triethylenetetramine diVB-TETA (or diVB-TETA-Cu) within a PVDF substrate, using a divinylbenzene cross-linker. Fourier transform infrared FT-IR spectroscopy showed the successful in situ polymerization of the chelating monomer within the PVDF texture. The permeation study showed that the ion-imprinted membrane has a Cu2+ selectivity factor of 3.78, while the non-imprinted membrane has a Cu2+ selectivity factor of 1.65. In addition the Cu2+ permeation flux in the imprinted membrane is 3.9 time that in the non-imprinted membrane For the second membrane, the synthesis is similar to the first membrane for both non-imprinted and imprinted forms (polyvinylidene fluoride-divinylbenzyl-triethylenetetramine-N,N'-methylenebis(acrylamide) (PVDF/diVB-TETA-N) and PVDF/diVB-TETA-N-Cu respectively), except that the used cross-linker was N,N'-methylenebis(acrylamide). In addition, sodium 4-vinylbenzyl sulfonate was added in selected percentages, (5-15% mol), to enhance the permeation flux. FT-IR spectroscopy analysis of the prepared membranes confirmed the chemical structure of diVB-TETA-N and sulfonate group into PVDF. Permeation and selective separation studies for the prepared membranes showed that the ion-imprinted membrane has a higher selectivity for copper permeation over the non-imprinted membrane. However imprinted membrane showed a lower flux for the permeated cations than that of the non-imprinted membranes The addition of the sulfonate groups to the prepared membranes enhanced the flux of the permeated cations, but the copper selective permeation decreased for both types (non-imprinted and ion-imprinted). Moreover, the ion-imprinted membrane PVDF/diVB-TETA-N-Cu showed a lower flux for the permeated cations than that of the non-imprinted membranes PVDF/diVB-TETA-N. Selective separation factors decreased to unity when the content of the sulfonate groups increased to 15% mol. Ion imprinted membrane prepared with 10% of sulfonate group showed optimum copper selectivity factor (α = 30304) and permeation flux for copper (0.4949 μmol cm‒2 h‒1) The third membrane (non-imprinted Selemion TM cation exchange membrane-divinylbenzyl-triethylenetetramine (CMV-S/diVB-TETA) and ion-imprinted CMV-S/diVb-TETA-Cu forms) was prepared by in situ polymerization of the chelating monomer, diVB-TETA (or diVB-TETA-Cu), on the surface of the commercial cation exchange membrane, Selemion, using divinylbenzene as cross-linker. FT-IR spectroscopy confirmed the chemical structure of the chelating polymer on the CMV-S membrane surface. Permeation study showed that ion-imprinted CMV-S/diVB-TETA-Cu membrane reached high separation factor (α = 17), yet the flux is low (0.0391 μmol cm‒2 h‒1). Non-imprinted CMV-S/diVB-TETA membrane of thickness (0.115±0.005 mm) using cross-linker (10% DVB) showed reasonable copper selectivity factor (α = 2.723) and permeation flux (0.433 μmol cm‒2 h‒1) / Thesis / Doctor of Philosophy (PhD)

Fine/nanoscale carbonitrides of microalloying elements such as Nb, Ti, and V play a significant role in the strengthening of HSLA steels. Site-specific analysis of the precipitates in different heterogeneous microstructural areas within realistic alloys is limited and the competition of different precipitates has not been discussed in detail. In this work, the relationship of precipitates/clusters with microstructure has been analyzed by site-specific methods and a simple model has been created to describe the competition between strain-induced precipitation and (Ti, Nb) (C, N). Firstly, the spatial distribution of precipitates and microstructure heterogeneity in an X70 steel were investigated by site-specific analysis method. The quantitative analyze the precipitates reveals that strain-induced precipitation of fine NbC particles (5-20 nm) on dislocations was suppressed by the large (Ti, Nb) (C, N) precipitates. The similarity of precipitates in each location suggests that the local features (such as strain and grain size) in the final microstructure arise from phase transformations during cooling. Secondly, the microstructural evolution during coiling and its effects on the mechanical properties of a vanadium microalloyed steel were investigated. Experimental findings showed that during holding at 500 ºC, nano precipitates (<10 nm) containing V and N nucleated heterogeneously, primarily in areas with high Kernel Average Misorientation (KAM) values. These areas contained a larger number of dislocations, which acted as nucleation sites for the precipitates. The effect of precipitation strengthening was not significant and was offset by softening caused by the aging of bainite and associated recovery of dislocations. Thirdly, in the HSLA steel with both V and Nb additions, nano precipitates were found to preferentially form around dislocations and grain/sub-grain boundaries in high KAM areas associated with bainite. Precipitates were frequently observed around cementite in low KAM areas, which were identified as granular bainite. Interphase clusters were also discovered in low KAM areas behind the ferrite/austenite interface. Analysis of the results indicated that the precipitation of micro-alloyed particles on cementite may reduce the contribution of precipitation hardening achievable through microalloying. Finally, a competition model between strain-induced precipitates (SIP) and epitaxial growth in micro-alloyed austenite has been developed. Using this model, it is possible to estimate the effects of process parameters (T, applied strain), the number density of pre-existing TiN particles, and steel composition on the precipitation process. Through the various studies achieved here, the aim to understand the relationship between the precipitates and different microstructures and develop the competition models has been accomplished. These works provide a relatively new workflow to investigate the precipitates within the steel, especially in site-specific areas, and also allow us to predict the precipitation of NbC by selecting desired temperature range, applied strain, and number density of pre-existing TiN precipitates. / Thesis / Doctor of Philosophy (PhD)

Seismic time-lapse monitoring of production is an important tool used to efficiently drain a hydrocarbon reservoir. Repeat seismic surveys may be used, because the seismic method is sensitive to the reservoir fluid. A prominent seismic attribute is the reflectivity (or amplitude) as a function of offset (AVO) which strongly depends on material properties, and hence, on the pore fluid. Repeat surveys, however, are very costly. To reduce the risks, the repeat survey is simulated on a computer for a number of different scenarios. Hence, the objectives of this study are to predict the seismic responses after five years of production of the reservoirs at the well locations, correlate the seismic attributes to fluid conditions in the reservoirs, assess the detectability of changes in AVO attributes due to changes in fluid conditions, and determine which attribute is more diagnostic of fluid changes. Petrophysical models were generated for different pore fluids using well logs from a field in the Gulf of Mexico. Synthetic seismograms were then calculated using a layerstack scheme to study the effects of the reservoir fluids on AVO. Compared to idealized half-space models, it was found that the AVO responses are contaminated by the overburden and the thinness of the reservoir. In order to remove transmission loss due to overburden effects, the synthetic AVO curves were scaled by normalizing an overburden-over-half-space model to an idealized analytical Zoeppritz model. In a second step, an offset-dependent overburden correction was applied using a low order polynomial, which was fitted to the amplitude ratios between the overburden/half-space model and the idealized model. Finally, a zero-offset tuning correction was applied. The results of the AVO analyses showed that some errors were unresolved using the applied overburden and tuning corrections, and amplitudes at large offsets were possibly contaminated by multiples and converted waves. Since there is no shallower production or steam injection for this particular field, the repeat surveys should have the same overburden, tuning, multiple-related and converted wave contamination. It appears reasonable to assume that any changes in amplitude between the repeat surveys would be due to fluid saturation changes. Therefore, it was concluded that it is not necessary to attempt to remove the overburden and tuning effects. Results from the AVO analyses of the uncorrected models showed that AVO attributes should be a useful tool to detect reservoir conditions during the production of the field. Generally, the water-flood changes the AVO by decreasing the intercept and increasing the gradient from the in-situ oil/gas cases. The relative changes in both intercept and gradient due to the water-flood are detectable assuming a 20% relative-change detection threshold, and gradient is more diagnostic because the relative change in gradient is very large compared to that for intercept. / Master of Science

Estimation of reservoir fracture parameters, fracture orientation and density, from seismic data is often difficult because of one important question: Is observed anisotropy caused by the reservoir interval or by the effect of the lithologic unit or multiple units above the reservoir? Often hydrocarbon reservoirs represent a small portion of the seismic section, and reservoir anisotropic parameter inversion can be easily obscured by the presence of an anisotropic overburden. In this study, I show examples where we can clearly observe imprints of overburden anisotropic layers on the seismic response of the target zone. Then I present a simple method to remove the effect of anisotropic overburden to recover reservoir fracture parameters. It involves analyzing amplitude variation with offset and azimuth (AVOA) for the top of reservoir reflector and for a reflector below the reservoir. Seismic CMP gathers are transformed to delay-time vs. slowness (tau-p) domain. We then calculate the ratio of the amplitudes of reflections at the reservoir top and from the reflector beneath the reservoir. The ratios of these amplitudes are then used to isolate the effect of the reservoir interval and remove the transmission effect of the overburden. The methodology is tested on two sets of models - one containing a fractured reservoir with isotropic overburden and the other containing a fractured reservoir with anisotropic overburden. Conventional analysis in the x-t domain indicates that the anisotropic overburden has completely obscured the anisotropic signature of the reservoir zone. When the new methodology is applied, the overburden effect is significantly reduced. The methodology is also applied to an actual PP surface reflection (Rpp) 3D dataset over a reservoir in the Arabian Peninsula. Ellipse-fitting technique was applied to invert for two Fracture parameters: (1) Fracture density and (2) fracture direction. Fracture density inversion results indicate increased fracturing in the anticline structure hinge zone. Fracture orientation inversion results agree with Formation MicroImaging (FMI) borehole logs showing a WNW-ESE trend. This newly developed amplitude ratio method is suitable for quantitative estimation of fracture parameters including normal and tangential “weaknesses” (ΔN and ΔT respectively). Initially, inversion of conventional AVOA for ΔN and ΔT parameters indicates that the ΔN parameter is reliably estimated given an accurate background isotropic parameter estimation derived from borehole logging data. While ΔN parameter inversion is successful, inversion for ΔT parameter from Rpp information is not, presumably due to the dependence of ΔT estimation on many medium parameters for accurate prediction. The ΔN parameter is then successfully recovered when applied to the amplitude ratio values derived from synthetic data. It is important to recognize that ΔN parameter is directly proportional to fracture density and high ΔN values can be attributed to high crack density values. The ΔN parameter inversion is also applied to the amplitude ratios derived from real seismic data. This inversion requires fracture azimuth data input that is obtained from the fracture direction inversion using ellipse-fitting technique. The background Vp/Vs ratio. / text

The primary objective of this thesis is to develop a methodology for fast, yet accurate temperature estimation during design space exploration. Power and temperature of modern day systems have become important metrics in addition to performance. Static and dynamic power dissipation leads to an increase in temperature, which creates cooling and packaging issues. Furthermore, the transient thermal profile determines temperature gradients, hotspots and thermal cycles. Traditional solutions rely on cycle-accurate simulations of detailed micro-architectural structures and are slow. The thesis shows that the periodic power estimation is the key bottleneck in such approaches. It also demonstrates an approach (FastSpot) that integrates accurate thermal estimation into existing host-compiled simulations. The developed methodology can incorporate different sampling-based thermal models. It achieves a 32000x increase in simulation throughput for temperature trace generation, while incurring low measurement errors (0.06 K- transient,0.014 K- steady-state) compared to a cycle-accurate reference method. / text

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Semiconductor nanowires (NWs) are anticipated to play a crucial role in future electronic and optoelectronic devices. Their practical applications remain hindered by an urging need for feasible strategies to tailor their optical and electronic properties. Strategies based on strain and alloying are limited by issues such as defects, interface broadening and alloy scattering. In this thesis, a novel method to engineer the optoelectronic properties based on strain-free periodic structural modulations in chemically homogeneous Nanowire Twinning Superlattices (NTSLs) is experimentally demonstrated. NTSLs are an emerging new class of nanoscale material, composed of periodically arranged rotation twin-planes along the length of NWs. The main objective of this thesis is to establish the relationship between the electronic energy band gap (Eg) and the twin-plane spacing (d) in NTSLs, quantified using a periodicity parameter, based on ZnSe. ZnSe was chosen because of its excellent luminescence properties, and potential in fabrication of optoelectronic devices in the near-UV and blue region of the spectrum. A prerequisite to establishing this correspondence is a prior knowledge of the photoluminescence (PL) response and the nature of fundamental optical transitions in defect-free single crystal ZnSe NWs with zinc-blende (ZB) and wurtzite (WZ) crystal structures. There has been no systematic work done yet on understanding these fundamental optical processes, particularly on single NWs and in relation to their crystalline microstructure. Therefore, the secondary objective of this thesis is to study the influence of native point defects on the optical response of single ZnSe NWs in direct relation to their crystalline microstructure. The PL response from single ZB and WZ NWs was determined unambiguously, and excitonic emission linewidths close to 1 meV were observed, which are the narrowest reported linewidths thus far on ZnSe NWs. Based on this and extensive optical and structural characterization on individual NTSLs, a linear variation in Eg is shown through a monotonic shift in PL peak position from ZnSe NTSLs as a function of d, with Eg's that lie between those of ZB and WZ crystal structures. This linear variation in Eg was also validated by ab Initio electronic structure calculations. This establishes NTSLs as new nanoscale polytypes advantageous for applications requiring tunable band gaps.