Characterization of Potential Wear Sources in Knee Arthroplasty Prostheses After In Vivo Function

Total joint arthroplasty (TJA) is a common procedure generally performed in patients with osteoarthritis. While TJA continues to be a successful treatment for degenerative joint disease, there are many studies that demonstrate wear and its sequelae as the major limitation of joint replacement longevity. Previous studies have shown that wear debris originates from four main locations: articulating surfaces, modular component surfaces, surfaces of fixation, and adjuvant fixation devices. Each of these possible wear sources can initiate the cascade of failure associated with wear-induced osteolysis and lead to subsequent revision surgery. The objective of this thesis is to characterize the in vivo performance of knee prostheses by quantitatively assessing performance at different potential wear-inducing interactions, including bearing surfaces and modular articular surfaces. The objective will be accomplished through three studies that will aim to investigate different wear modes. The purpose of Study 1 is to explore the relationships between femoral component surface roughness, polyethylene insert damage and in vivo duration through the evaluation of metal-polymer UKA bearing couples that were retrieved after 1 to 19 years of in vivo service. This study characterizes the distribution of damage on matched metal-polymer bearing couples of retrieved UKA and quantifies ranges of surface roughness corresponding to the different damage modes visually identified on both bearing surfaces. The purpose of Study 2 is to characterize the damage of retrieved knee replacement bearing couples that have experienced complete polyethylene wear-through, while considering the material properties of common alloys used to fabricate femoral components and tibial baseplates, including cobalt-chrome alloy, titanium alloy, and oxidized zirconium alloy. The purpose of Study 3 is to evaluate the clinical outcomes of 84 patients implanted with primary TKA prostheses of a single design that utilizes a Morse taper feature for attaching a modular tibial stem. The results from this thesis provide clinically relevant data for understanding the performance of knee prosthesis designs under physiologic conditions. Additionally, this thesis provides relevant surface roughness values for prostheses with in vivo function for assessing the predictive capabilities of in vitro simulation and analytical models

What the Eyes See and the Mind Knows

Every morning as I set out for a walk, my mind starts trailing off as my eyes scan my neighborhood; I begin to wander into a daydream, tuning in to the pictures that I paint in my mind, imposing what I am observing into a new possibility of reality. This exploration into the lives of others in this world is a breath of fresh air, a reprieve from the demands of daily life. I am inspired by the narrative that is unknowingly being written into the earth by my neighbors, intrigued by the solutions that they come up with for cultivating spaces for growth and fertility while having limited spatial capabilities. My mixed media prints and drawings are rooted in the intersections between man-made structures interacting with nature and how the mind perceives a memory of what is seen through imagination and invention. The foundation for my body of work is built from old textbook illustrations, photographs from outdoor encounters and my experiences as a gardener. I reference structural objects that resemble greenhouses, garden boxes, and cold frames; such structures create spaces that propagate the potential for growth, which is a hoped-for outcome with unseen processes and perils. Retranslating these images and concepts between my mind and my hand helps to mimic an action of toggling between airy daydreams and physical reality. These homemade solutions in the garden become drawn and designed forms that similarly grow into a variety of spatial transformations. I wrestle with reconciling the tension between ephemeral moments and permanent fixtures with material choices and applications in the work. The residue of a fleeting moment is reflected in drawn elements, I apply powdered graphite as if to evoke a cloud of settling dust, revealing bits and pieces of something recognizable. I make high-contrast marks in colored pencil to resemble the spray paint markings I see each day on sun-bleached grass. I layer powdered charcoal gradually to resemble a shadow, a figment of a memory. The acid-bitten lines from the copper plate bring me back to reality with the physicality and time of the process. The image is embedded below the surface of the plate as it has imprinted upon my mind. By creating a repeatable image and combining it with an intuitive approach to material application, I encourage the viewer to see and feel in this way, as forms appear, disintegrate, reappear in alternative ways in a visual and mental field. The transference of the image and idea takes place again in the viewer, as it resides in their mind’s eye. Through this work, one may start to wonder; one’s mind begins to trail off into deep thought. The mental escape has taken place, but the body remains in the present. My art-making process begins with an obsession over collected and observed “garden-solution” imagery, where, through making multiples, I create familiar spaces that speak to the multitude of possibilities for success in cultivating growth and imagination in everyday life. Advisors: Karen Kunc and Francisco Sout

A preformulation study of pyridoxal hydrochloride for solid dosage form desigh and development

A Dissertation Submitted to the Faculty of Medicine, University of the Witwatersrand, Johannesburg for the Degree of Master of Pharmacy. Johannesburg, August 1991In this dissertation physicochemical properties of the Bs vitamer, pyridoxal hydrochloride (PL HC1), are investigated with the aim of generating the necessary profile for the rational development of a stable, safe and effective formulation containing this drug. Recent research suggests that administration of PL HC1 may be particularly effective in raising the depleted intracellular pyridoxal phosphate levels found in many asthmatics treated with theophylline. The solubility characteristics of PL HC1 suggest that its absorption and bioavailability should not be problematicIT201

Infrared spectra of molecules and materials of astrophysical interest

The Raman spectra of gaseous, liquid and solid, and infrared spectra of gaseous and solid isopropylamine-d sub 0 and -d sub 2 was investigated between 4000 and 50 cm superscript -1. Differences between the spectrum of the solid phase and that of the fluid phases were interpreted in terms of an equilibrium between low energy s-trans and high energy gauche conformers, and a complete vibrational assignment was proposed for the s-trans conformer. The far infrared spectra of the gaseous compounds contained bands due to the asymmetric amino and coupled methyl torsions; the assignment of these bands was aided by observation of a number of two quantum transitions for each vibrational mode. The asymmetric potential functions were calculated, which resulted in values for the enthalpy differences between conformers in the gaseous phase of 446 and 523 callmole for the sub 0 -d and -d sub 2 compounds, respectively. The methyl torsional potential function of isopropylamine-d sub 0 was calculated which led to a value for the barrier height to internal rotation of the methyl rotors of 4.23 + or - 0.06 kcal/mole. Values for the ideal gas thermodynamic functions were calculated over a range of temperatures

Infrared spectra of molecules and materials of astrophysical interest Quarterly progress report, 15 jun. - 15 sep. 1970

Infrared spectra of molecules and materials of astrophysical interest Quarterly progress report, 15 Jun. - 15 Sep. 197

Infrared spectra of molecules and materials of astrophysical interest Quarterly progress report, 15 Dec. 1970 - 15 Mar. 1971

Vibrational spectra of molecules expected in Jovian atmospher

Infrared spectra of molecules and materials of astrophysical interest

The vibrational spectra from 4,000 to 33/cm of several molecules which may be present in the atmosphere of the Jovian planets or exist in outer space were studied. These studies have been made to provide vibrational frequencies which can be used to: (1) determine the composition of the cloud covers of several of the planets, (2) provide structural information under favorable circumstances, (3) provide necessary data from which accurate thermodynamic data can be calculated, and (4) furnish information as to the nature of the potential energy function of the molecules and forces acting within them. Some of the molecules studied can be produced photochemically from methane, ammonia, and hydrogen sulfide which are thought to be constituents of the planets with reducing atmospheres. Some of the compounds will polymerize under ultraviolet radiation and drop out of the atmospheres. However, planets with a hot base, like that of Jupiter, may rebuild molecules destroyed photochemically. These criteria were used in selecting the compounds under study

Infrared spectra of molecules and materials of astrophysical interest

The vibrational spectra from 4000 to 33 cm-1 of several modecules which may be present in the atmosphere of the Jovian planets are studied to provide vibrational frequencies which can be used to: (1) determine the composition of the cloud covers of several of the planets; (2) provide structural information under favorable circumstances; (3) provide necessary data from which accurate thermodynamic data can be calculated; and (4) furnish information as to the nature of the potential energy function of the molecules and forces acting within them. Some of the molecules are produced photochemically from methane, ammonia, and hydrogen sulfide which are thought to be constituents of the planets with reducing atmospheres. Some of the compounds polymerize under ultraviolet radiation and drop out of the atmospheres. However, planets with a hot base, like that of Jupiter, may rebuild molecules destroyed photochemically

Infrared spectra of molecules and materials of astrophysical interest Quarterly progress report, 15 Sep. - 15 Dec. 1970

Vibrational spectra of molecules and solid materials from 4000 to 33 cm in Jovian atmospher