Past Projects‎ > ‎

2013-14

Zach Donahue and 
Evelyn McChesney - Engineering

A solar, gravity-powered hybrid prototype was engineered with the purpose of expanding the range remote exploration using environmentally friendly energy sources. The final prototype generates gravitational energy with a generator and AC/DC circuit salvaged from a crank flashlight. An Arduino MEGA distributes DC power to motors that drive wheels via 58:1 Tamiya gearboxes while a gear train using an idler gear engages the rotating electromagnetic generator as the rover rolls downhill. Gravitational energy is harvested from the generator using Faraday’s Law, where the generator is geared with a multi-speed gearbox to the axle in a way that the generator only engages when rolling downhill. Microcontrollers calculate optimal gear ratios for the generator gearbox to produce efficient energy output based on length and average angle of a slope, as well as the expected time for the rover to roll down a hill with the selected gear ratio. An alkaline battery is used to store DC power from a combination of five solar panels and an electromagnetic generator to prove energy to heaters that keep the circuitry warm. Peak efficiency of the prototype is 1.188 kg rover mass. 

Claire Drysdale -
Chemistry 

Given my interest in visual arts, particularly artistic patinas, the purpose of this study was to gain insight into the chemistry of artistic patination, with specific goals of identifying and characterizing synthetic patinas realized from artistic recipes. Six artistic copper patinas (A-F) were synthesized using artistic recipes obtained from artist’s forums and blogs, You-tube videos, and do-it-yourself patination guides. Chemical composition of the resulting patinas was found with polarized light microscopy, regular light microscopy, and Raman spectroscopy. Patina A was identified as cupric sulfide (CuS), Patina B as gerhardtite (Cu2(NO3)(OH)3), Patina C as a combination of gerhardtite and clinoatacamite (Cu2(OH)3Cl), and Patina E as basic cupric acetate. Though Patinas D and F were not fully chemically identified, the results suggest that Patina D is likely a form of cupric hydroxide, and Patina F is likely a form of cuprous oxide. Results will be used to develop scientifically based copper patina recipes and techniques, which will ultimately be compiled into a reference guide for use by artists.

Madison Ernst and 
Patty Zhao - Environmental Science

Pseudomonas putida F1 are bacteria that may be useful in bioremediation efforts to clean up contaminated marine shorelines, soil environments, surface water, and ground water. These bacteria are naturally found in soil and aquatic environments and show a chemotactic response to a number of hazardous aromatic hydrocarbons. In chemotaxis, bacteria use receptors to detect nutrients in their environment. However, amino acids are more attractive nutrients for P. putida F1 than aromatic hydrocarbons are, so the receptors in the bacteria that respond to amino acids must be identified and knocked down before the bacteria can be used in bioremediation. Our work involved identifying the receptor that is responsible for chemotactic response of P. putida F1 to the amino acid L-alanine. Bioinformatics and pertinent literature were used to establish metabolic pathways for alanine and arginine in P. putida F1. Then, swim assays were run that showed Pput_4234 also plays a significant role in chemotaxis of P. putida F1 to alanine (p = 0.0004). However, the complementary experiment did not verify this result, suggesting that the vector used to synthesize the original complement strain did not insert the Pput_4234 receptor into the P. putida F1 genome properly. Therefore, a new P. putida F1 complement strain was cloned using an alternative vector. This work is an important step in bioengineering P. putida F1 to sense and metabolize less “appetizing” aromatic hydrocarbons. With the help of our research, bioremediation can be transformed from a secondary polishing step to a primary form of environmental cleanup. 

Darartu Gamada and 
Rustam Kosherbay - Engineering

A miniature Langmuir trough (3.5 x 50 mm) was engineered to study lipid membranes of Archaea, which are extremophiles that can be used to track climate change over Earth’s history. Because Archaeal lipids are prohibitively expensive, the trough was designed to study only 0.0045 µL of sample. Unlike commercially available Langmuir troughs, our trough is held together by compression instead of glues that disrupt monolayers being studied, employs a specially designed Teflon slit, and uses a Wilhelmy plate constructed from filter paper instead of from platinum. The trough is controlled with Arduino microcontrollers that were programmed using Arduino and LabVIEW code with an I2C connection to move a Firgelli linear actuator while water level is maintained through a rescaled photodiode/laser system in conjunction with two peristaltic pumps. Results showed that the trough successfully measures surface tension of a lipid monolayer. The University of Minnesota Duluth has expressed interest in using the trough to study Archaeal lipids taken from core samples of Lake Superior. Changes in concentration and makeup of Archaeal lipids in membranes extracted from the core samples will be studied to track changes in lake-water temperatures over time.

Luis Guzman and 
Julia Joern - CATEGORY

This study involved engineering a solar hydronics communications network to control heat flow in a well-insulated house in Roseville, Minnesota. A RS485 network—the industry standard for RS485 communication—was installed that consists of Arduino Mega and Arduino Micros. Software was written in C/C++ to run 100 Dallas DS18B20 temperature sensors, one Sensirion SHT11 humidity sensor, and eleven Laing D5 Solar 720B circulators that direct heat flow to heat-storage components from solar collectors or hydronics system components. In order to improve reliability of the RS485 network, Modbus protocol was strictly adhered to in  developing the control system and programming language. A unique aspect of the software developed in this study is that it adjusts to time of day, outside temperatures, dew point, humidity, and time of year in order to make logical decisions about where to distribute heated water from solar panels. Final testing of the communications network showed 100% success rate. Because the network can be easily modified and tailored for individual system needs, it is applicable to any solar-powered hydronics system.

Sofie Kim and 
Jake Levy - Chemistry

The 1,2,3-triazole is a stable and biologically active organic compound that can be used in a variety of applications, including pharmaceutical chemistry. The purpose of this study was to synthesize 1,2,3-triazole derivative isomers using synthesis protocols that maximize efficiency in terms of time, reagent quantities, and use of ‘greener’ chemicals.

By adapting protocols developed by Huisgen, regioisomerically controlled copper(I)-catalyzed azide-alkyne cycloaddition was used to synthesize the 4-alcohol-1,2,3-triazole intermediate. Because one goal was to use inexpensive, readily available materials for these syntheses, copper(II) sulfate was reduced with sodium L-ascorbate (vitamin C) in situ to produce the copper(I) catalyst. Then, the 4-alcohol-1,2,3-triazole intermediate was oxidized to produce the 4-acetyl-1,2,3-triazole using Clorox® bleach (6% sodium hypochlorite) and acetic acid (glacial). Since the stoichiometry of this oxidation reaction using bleach and acetic acid is not known, amounts of bleach and acetic acid were varied to determine the combination that best optimized yield and reaction time. Initial protocols for synthesis of two precursors to the 5-acetyl-1,2,3-triazole, the 5-trimethylsilylethynyl-1,2,3-triazole and the 5-ethynyl-1,2,3-triazole, were developed.

Trevor Larson and 
Nath Samaratunga - Medicine

The goal of this study was to determine the potential of using mesenchymal stromal cell (MSC) therapy in suppressing immune responses that result from bronchiolitis obliterans syndrome (BOS). Tissue was analyzed from a mouse model (Mus musculus) where BOS had been induced followed by treatment with MSCs. Hematoxylin and eosin (H&E) staining was used to visualize bronchioles. Next, immunohistochemistry and immunofluorescence were considered for staining cells: immunofluorescence was selected because it allows for co-staining. Three anti-inflammatory antigens (CD206, CD4, and Foxp3), one anti-inflammatory cytokine (IL-10), and one pro-inflammatory antigen (CD11c) were chosen for study. Results suggest that MSCs reduce inflammatory response that results from BOS. Results also suggest that beneficial effects of MSCs may be due to the generation of alternatively-activated macrophages and T-regulatory cells. This is supported by significant increases of CD206 in groups were treated with MSCs (p = 0.032), which is consistent with alternatively activated macrophages that stimulate immune cell response. To our knowledge, there have been no other studies that have reported these results.

Easton McChesney and 
Wolfgang Ofstedal - Environmental Engineering

Dissolved phosphates in stormwater that run off into ponds, streams, and lakes are a pressing environmental problem because algae blooms that result from phosphate eutrophication consume all available oxygen in the water. A phosphate filter system was engineering that employs a chemical precipitation technique to remove dissolved phosphates from stormwater runoff.

Three sets of filters were constructed from 2 x 6 inch PVC pipes, each with different combinations of steel-wool grades, density, and numbers of layers for a total of 27 filters. Flow-rate, head-loss, and phosphate-removal tests were run on each set of filters over the course of ten weeks. Results showed that a filter constructed from three layers of grade-3 steel wool with a density of 1200 g/m3 is the best combination of filter media for maintaining flow rates without overflow during a “two-year storm event.” This filter resisted buildup of rust that has the capacity to clog the filter during use. Furthermore, the filter successfully removed up to 60% of dissolved phosphates from a standard 1.37 x 10-6 M Na3PO4 solution, chosen based on the national average stormwater phosphate ion concentration.

Matt McMillan and 
Peter Metzger - Physical Sciences

Rechargeable lithium-ion batteries are sources of energy in electronics, aerospace applications, and electric vehicles; however, they are inherently susceptible to metal plating. While plating problems are mitigated by protective surface films that form on current collectors during battery use, little work has been done to understand film formation. The goal of this study was to develop an experimental design capable of quantitatively assessing stability and protective capability of surface films formed in two commonly used lithium-ion battery electrolytes: lithium hexafluoroarsenate and lithium hexafluorophosphate. Cyclic polarization voltage sweep rates were determined for a titanium-coated piezoelectric quartz crystal that served as a current collector. Gamry software interface was used to measure open-circuit voltage of each cell. Cyclic polarization tests were then run at the determined sweep rates, with positive scans. Mass of film formation was tracked using quartz crystal microbalance with dissipation (QCM-D). Results showed a marked contrast in film formation and corrosion between the two electrolytes tested. Furthermore, the test design enabled precise quantitative measurements of surface film formation and corrosion of the current collector, suggesting the experimental design is effective as a quality control tool for assessing protective surface films on current collectors in lithium-ion batteries.

Claire Simpson
 - Chemistry

Drimentines are a novel family of alkaloids that exhibit antibiotic, antifungal, and anticancer activities. Nine drimentines (A-H and 3,25-dihydrodrimentine E) have been found in nature; however, only small amounts of drimentines have been isolated from natural sources, and only drimentines A, F, and G have been fully synthesized using synthetic procedures. The purpose of this study was to synthesize the cyclo-L-tryptophan-L-proline portion of drimentine C. This paper details the retrosynthesis design from which the forward synthesis of cyclo-L-tryptophan-L-proline from L-tryptophan and L-proline was developed. The forward synthesis proceeded in a three-step process that included Boc protection of L-tryptophan, esterification of L-proline, and a three-part condensation deprotection sequence to form the cyclo-L-tryptophan-L-proline. Novel purification procedures to purify products are also outlined. A total of 1.7071 g of the cyclo-L-tryptophan-L-proline were successfully produced over four successive syntheses. Future goals include synthesis of the pentacyclic component of drimentine C from the cyclo-L-tryptophan-L-proline using a possible synthesis pathway developed by this author, followed by total synthesis of drimentine C. Ultimately, drimentine C will be evaluated in vitro against cancer tumor cell lines to determine its effectiveness as an anti-cancer agent.

Elisa Villafana
 - Plant Science

The neonicotinoid insecticide thiamethoxam is implicated in declines of honeybees that are critical for crop pollination; however, the company that manufactures thiamethoxam claims it improves crop quality and yields. This study tested this claim. In a controlled laboratory study, 120 plants from untreated soybean seeds and 120 plants from thiamethoxam-treated soybean seeds were grown at temperatures, humidity, and sunlight hours to mimic early and late 2012 Minnesota planting conditions. Results showed that, on average, plants grown from untreated seeds emerged sooner (p = 0.0007), had larger leaf area (p = 0.01), and showed healthier root architecture (p < 0.05). Because insecticides may react differently in a nature environment than in potting soil, a complementary field study was conducted. Untreated and treated soybean seeds were planted in sixty-four 27.0 m2 plots laid out in randomized complete-block designs. Results showed no significant difference in emergence, leaf area, or root parameters between the two treatment groups (p > 0.05); however, plants grown from untreated seeds were significantly more vigorous (p = 0.01). These results refute claims that farmers will encounter healthier plants and higher crop yields from thiamethoxam-treated soybean seeds. Results suggest that farmers should treat soybean crops with insecticides other than thiamethoxam.

Elliott Weiler
 - Genetics

The purpose of this study was to assess genetic susceptibility for developing the gum disease periodontitis. An extensive literature search identified two pro-inflammatory cytokines, IL-6 and IL-1, that show high correlation to inflammation in periodontitis. Three mutation sites IL-6 -174 rs1800795, IL-1a rs17561, and IL-1brs1143634 were chosen for study. Combinations of IL-1a and IL-1b genotypes were classified as either positive or negative based on combinations that may result in more inflammation in periodontitis. PCR, rotor-gene melt-curve analysis and LabChipGX electrophoresis where used to determine genotypes at the mutation site for IL-6 (either C/C, C/G, or G/G depending on genetic makeup), and for IL-1a (either G/G, G/T or T/T) and for IL-1b (either C/C, C/T or T/T) for 160 dental patients that had American Dental Association (ADA) periodontal classifications.

While literature suggests that patients with the IL-6 G/G genotype and the positive IL-1 have more severe inflammation due to periodontitis than patients with the IL-6 C/C genotype and the negative IL-1 combination do, results of this study do not indicate these genotypes are genetic markers for periodontitis (p = 0.28). Furthermore, results showed no significant correlation between between ADA classifications and patient age (p> 0.05).


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