BEE 4530 - 2007 Student Papers

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https://hdl.handle.net/1813/7902

This is a collection of student papers for BEE 4350 for the year 2007.

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Now showing 1 - 10 of 11

Thermal Imaging and Analysis for Breast Tumor Detection
Kwok, Jeni; Krzyspiak, Joanna (2007-07-10T13:53:21Z)
Breast cancer is the most common cancer among women, except for non-melanoma skin cancers. Women in North America have the highest rate of breast cancer in the world and the chance of a woman developing this cancer is 13% (ACS). Resulting deaths have been decreasing mainly due to early detection and increased awareness. This study analyzes the use of a thermogram as a potential method for breast cancer detection. The breast is evaluated by an infrared camera and a temperature profile is produced. Proper study of the image can show if a tumor is present. A computer simulation of this procedure was used to model the temperature profile and its change as certain parameters vary. Results show that in the present of a tumor, there is a difference in surface temperature of the breast. Input values such as tumor size, tumor location, heat transfer coefficients, and perfusion rates were varied to determine the reliability of a positive result despite differences in each unique breast from woman to woman.
Oral Transmucosal Delivery of Fentanyl Citrate for Breakthrough Cancer Pain Relief
Beutel, Bryan; Lim, Irene Isabel; Lin, Tricia; Ma, Jameson (2007-07-10T13:49:42Z)
Episodes of breakthrough cancer pain are relatively common occurrences for patients undergoing cancer treatments. Characterized by pain unrestrained by traditional medications, these physical burdens impose a significant degree of suffering. In order to control and eliminate this pain, Actiq, a pharmaceutical lollipop, has been developed to provide rapid oral transmucosal delivery of fentanyl citrate, a potent medicinal narcotic. To elucidate the pharmacokinetics of the drug under various dosages, a computer model of fentanyl diffusion in the oral cavity was designed in COMSOL. Upon solving the model process, concentration profiles of fentanyl in the mucosa over time were developed for various dosages. Sensitivity analyses were also performed to determine the effects of several parameters on fentanyl diffusion. The resulting concentration profiles showed that peak concentrations of 0.00079 g/m3, 0.0016 g/m3, and 0.0032 g/m3 for 200 ?g, 400 ?g, and 800 ?g dosages, respectively, were achieved at approximately 800 seconds. Additionally, based upon the sensitivity analyses, the fentanyl solubility and the lollipop radial dissolution rate have the greatest impact on fentanyl concentration and diffusion. Future research can be performed to optimize the drug diffusion by altering these two parameters, ultimately yielding a more effective Actiq product.
The Effect of the Diving/Wet Suit on the Survival Time in Cold Water Immersion
Chung, Chris; Shim, Ju Sok (2007-07-10T13:44:55Z)
In this study, we will compare the effect of normal clothes (assumed as bare skin) with effect of wetsuit in maintaining the core body temperature, produced by metabolic heat generations and blood flow heat generation, using COMSOL. A passenger is immersed in cold water after Titanic has shipwrecked, and the individual is waiting for rescue to come in time before his metabolic functions stop and die. We will compare two cases: with and without wetsuit on the passenger. Skin temperature or wetsuit temperature is assumed to be equal to cold water temperature, which is at 10 degrees Celsius, and the distribution of temperature throughout the body will be graphically shown as the time of body immersion in water increases. It is shown from the results that wetsuit can help maintain the normal core body temperature much longer than normal clothes/bare skin can in cold water immersion.
Lynah Rink: The Science of the Ice
Lund, Stephen; Mathew, Esha; Pratt, Kristamarie; Zacherman, Jonathan (2007-07-10T13:41:16Z)
Ice hockey is probably the most popular sports team at Cornell, easily selling out tickets to every game at the start of every year. Although eager fans study the team, plays, opponents, and results, it is doubtful that they pay any attention to the science behind the very ice the game depends upon. Our project seeks to look into the ice at Lynah rink, specifically the heat transfer processes involved in making the ice, maintaining it, and removing it in the off-season. We investigated how much time it would take to prepare the surface for ice hockey, how much time it would take to resurface the ice during a game, and lastly how much time it would take to melt all the ice and remove it during the off-season. We used a one-dimensional geometry with sixteen sections to model the eight layers of ice needed for the rink. Two sections represented one layer, equal to 0.3175 cm. Layers and boundaries were turned on and off depending on the part of the problem that was being solved for. Our initial results showed that it takes about four hours to place eight layers, equivalent to 2.54 cm of ice down on the rink. Conversely, it takes about five minutes for the 2.54 cm of ice to melt with the concrete slab heated. The resurfacing process, needed to be complete in less than fifteen minutes, was found by our model to take about six minutes. This value is subject to change from variation in the heat transfer coefficient and rink temperature, but our analysis found that even high values for these parameters still allowed resurfacing in a maximum of eight minutes. Melting was the least complex situation to model, and we found that it took about five minutes to melt the ice with the concrete heated to 60?C(333.15K).
pH-Dependent Drug Delivery Systems
Klosiewicz, Bryan; Legato, Joseph; Oh, Jason; Rivers, Shajuana (2007-07-10T13:35:19Z)
Gastric carcinoma, or stomach cancer, is a major disease in the world today. Although it only accounts for about 2% of all cancer cases in the United States, it is much more prevalent in nations such as Korea, Japan, Great Britain, South America, and Iceland. While the most common treatment for gastric carcinoma is surgery, there are chemotherapeutic alternatives including the application of doxorubicin, also known as Adriamycin?. However, as with nearly all chemotherapy drugs, doxorubicin causes dose-dependent toxicity that results in severe biological side effects and, potentially, death. Many of the adverse effects of doxorubicin may be attributed to the fact that it is normally administered intravenously; thus, although the drug?s target is the stomach, the doxorubicin is systemically rampant. Hence, we have developed a delivery system for doxorubicin that we hope will limit the drug?s action to the stomach alone. We begin with a means for encasing the doxorubicin inside two types of hydrogels whose diffusive properties vary depending on temperature and pH levels, such that diffusion may be maximized in the stomach and minimized at all other locations inside the gastrointestinal tract. This original design was modeled as a 1-D radial line to represent the spherical shape of the pill. After investigation, another design involving a hollowed out hemisphere was modeled and tested. Results comparison shows that the second design scheme is superior to the first both in outward drug flux and in the amount of drug able to be delivered. Ultimately, results of the study showed that pH-dependent drug release can be attained at a steady and reliable rate, with significantly greater rates of release inside the stomach. However, we were unable to attain a clinically adequate amount of total doxorubicin release with our model designs. Still, it may be possible to achieve medically useful results with pH-dependent drug delivery systems given certain technological improvements in the future.
Magnetic Resonance Induced Heating in a Vascular Stent
Chaudhury, Ankur; Khasnavis, Siddharth; Russell, Matthew; Sarathy, Vijay (2007-07-10T13:19:25Z)
It is standard hospital practice to remove metallic objects from patients prior to MRIs. Since magnetic resonance imaging employs changing magnetic fields, even everyday items such as jewelry or keys run the risk of overheating due to induced currents leading to Joule heating. A potential problem arises, however, when the metal is subcutaneously located in the form of a medical implant. The present study evaluated this scenario by using finite element analysis to model a vascular stent under the influence of a standard MRI field. COMSOL Multiphysics software was used to conduct finite element analysis on two different stent sizes, each in the presence and absence of blood flow. The stents were modeled as stainless steel (type 316L) with internal diameters of 5mm and 8mm, length of 40mm, and wall thicknesses of 0.18mm and 0.22mm. The tests revealed that under the influence of blood cooling, the stents modeled did not overheat or cause arterial damage. Specifically, the large stent resulted in a maximum temperature of 310.807 K and the smaller stent led to 310.230 K, each after 30 minutes of heating. In the unrealistic absence of blood flow, the large and small stents reached maximum temperatures of 318.851 K and 312.297 K respectively. Ultimately, given variance in blood flow the true solutions lie somewhere in between the blood perfusion and static flow models.
Patch Immunization: Transcutaneous Vaccination for the Cholera Toxin and Optimization of Immunization Cycles
Singh, Babu; Shoor, Priya; Shah, Avani (2007-07-10T13:12:05Z)
The main point of this analysis was to investigate the diffusion of the cholera vaccination through specific layers of the skin. The antigen was initially modeled through the skin directly to the blood stream. The antigen was also modeled with the presence of a network of Langerhans cells. There was a smooth concentration profile in the skin after one week of patch exposure in the absence of the LC network. However, there was discontinuity in the concentration profile when the LC network was present. The LC network functioned as a large enough sink term that the flux into the bloodstream was virtually zero. Therefore, we concluded that the LC network alone can create a cutaneous immune response. The LC network was enhanced with the presence of Imiquimod, a typical immune response modifier. The modifier increased the activity of the LC network, thus increasing the reaction rate of the LC cells. With Imiquimod there was a sharper discontinuity in the concentration profile at the LC network and the antigen flux into the blood stream is zero. The most effective enhancer tested was the MEMs microneedles, which increased the porosity of the skin and thus the diffusivity of the antigen through the skin. Contour plots of the skin showed absolute diffusion and consumption of the antigen into the LC network, while only partial consumption with the other enhancers tested. Concentration gradients were present in the ultrasonically and photo mechanically enhanced skin because they had weaker enhancing capabilities compared to the MEMs needles. The MEMs needles are the most effective in mass transfer, but are also the most evasive. Vaccines are usually given in cycles to increase the concentration of the antigen in the skin and bloodstream. When the patch was applied to the skin with no enhancer, the maximum concentration was achieved after 2.3 days. However, the maximum concentration in the skin is achieved sooner with the various adjuvants. For example, when the patch is applied with MEMs needles, the maximal concentration is achieved in the skin only after 1.2 hours of exposure. Immunization cycles presented in Glenn et al were simulated to determine the approximate concentration of the antigen at the center of the skin needed for an immune response. This concentration is 0.0038 mol/m^3. Therefore, it was assumed that if the concentration in the skin is close to this value, then an immune response will be initiated. The immunization cycles for each adjuvant used were then optimized.
Laser Irradiation of Tumors for the Treatment of Cancer: An Analysis of Blood Flow, Temperature and Oxygen Transport
Sood, Ravi; Nahlik, David; Nichols, Weston; Graham, Evan (2007-07-10T13:06:44Z)
It has been shown that hypoxic tumor cells are resistant to radiation and that increasing tumor oxygen levels via laser-mediated hyperthermia treatment increases tumor cell radiosensitivity. Hence, studies of the effects of laser irradiation on tumor oxygen levels are of great interest, as they allow for the optimization of hyperthermia treatment. Accordingly, the main purpose of this experiment was to develop a finite element model to simulate the heat transfer due to laser irradiation of tumor tissue, the blood flow through a tumor capillary, and the effect of changing temperature on blood flow rates and oxygen delivery to tumor tissue. This was achieved by using finite element models in COMSOL Multiphysics. We employed two geometries based on those used in a simliar study by He et al. [1]: a tumor-containing breast model to simulate laser heating of the tissue and a capillary and tumor tissue model to simulate the effect of heating on blood flow and tissue oxygen concentration. By plotting partial pressure of oxygen as a function of radius at three different points in the tissue, we observed that the oxygen concentration was greatest near the inlet and lowest near the outlet (as expected), and that at all points in the tissue, heating increased the tissue oxygen partial pressure to about the same extent (0.75 ? 1 mm Hg). Furthermore, sensitivity analyses suggested ambient air cooling at the breast surface to be ideal and a laser intensity of 18000 W/m2 to be optimal for hyperthermia treatment. The model we developed was validated by comparison to a similar model and has potential for use in future studies on optimization of hyperthermia treatment.
Optimizing Release from Reservoir Microcapsules
Hoang, David; Liu, David; Chen, Jennifer; Siu, Vince (2007-07-10T13:01:23Z)
Cytomegalovrius (CMV) retinitis is a common symptom of vision loss found in 20-30% of all acquired immunodeficiency syndrome (AIDS) sufferers. While there are no drugs that can cure permanent retinal damage by CMV, the drug ganciclovir has demonstrated efficacy against human cytomegalovirus infections and has been considered a first-line therapy in the treatment of sight-threatening cytomegalovirus infection in immune-compromised patients. The FDA-approved Vitrasert? implant, which is inserted at a localized region of the eye, is the current method of delivering ganciclovir intraocularly to patients with CMV. The Vitrasert? is a disc-like reservoir microcapsule that encapsulates ganciclovir in a polymer-based system. Maintaining a constant level of drug in the infected eye region is an important requirement in the design of this implant. The more constant the rate of drug release from the microcapsule, the more effective the drug will be. The objective of our model is to measure the diffusion of the ganciclovir release from the Vitrasert? into the surrounding tissue and to ensure toxic levels of the drug is not sustained. To accomplish this objective, the implant is simplified via axis-symmetry from a 3-D cylinder into a 2-D rectangle with homogeneous material properties, while the skin is reduced to a quarter-circle around our capsule. With our model, we are able to optimize the characteristics of the microcapsule to facilitate near constant drug release, which would be beneficial for many pharmaceuticals working with drug release from reservoir microcapsules.
Testicular Thermal Damage and Infertility from Laptop Use
Eibert, Erik; Ramirez, Marina; Salim, Saniya; Snider, Sarah (2007-07-10T12:55:15Z)
Today, more laptop computers are being used on a daily basis than ever before. One of the health risks associated with extended, repeated use by men is that of testicular damage, or reduced spermatogenesis due to increased temperatures in the groin region. Naturally, the scrotum is maintained 2oC below standard body temperature. However, the combination of increased temperature due to leg positioning to support a laptop on the thighs, and the potential for temperatures of 60oC to be reached on the bottom, outer surface of the device [11] present a health risk. Although temperatures of 50oC are more common, they still contribute to a rise of approximately 0.6oC in addition to a 2.1oC increase which is already due to leg positioning alone. The direct contact between the thigh and testicles is a significant factor in this increase in temperature, as well as the laptop heat generation. In the future, potential methods of reducing heat conduction into the body may be mitigated by additional heat sinks, or fans which may reduce the effects of extended periods of laptop use.

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