Contrast sensitivity is the ability to read words which have low contrast with the background. How much light is needed to identify letters of different contrast levels at low levels of light? How does age affect contrast sensitivity? A testing card was created with 25 letters, five at each of five different levels of contrast ranging from 20% to 3% saturation. We hypothesized that subjects would be able to read the five letters at 20% saturation with 50 lux of light, and the younger subjects would be able to read more of the letters than the older subjects. Fifty subjects, ages 10 to 75, participated. Participants were asked to identify any letters they could read at each of six levels of low light, ranging from 0 lux to 50 lux. With more light, there was improvement in the ability to see the letters. There was no linear relationship between age and contrast sensitivity; however, there was a noticeable decrease in some of the adults’ abilities to identify the letters. This research can be applied to improving safe driving at night or in situations, such as restaurant settings, where print must be read in low light, and it is important for accommodating people with certain vision impairments.

Coronary heart disease (CHD) is the number one killer worldwide and is responsible for 12.2% of all deaths. CHD is caused by a plaque buildup in the heart’s arteries, which can lead to a heart attack. If the plaque buildup level in the coronary arteries is high (i.e. ‘occlusion’), the most common treatment that involves surgery is the coronary artery bypass graft (CABG), which essentially bypasses the blocked area with a grafted blood vessel to bring blood to the heart muscle. Connecting the grafted blood vessel with the coronary artery is called anastomosis. For years, graft anastomosis has been done using suturing by hand. In the past several years, the U.S. Food and Drug Administration (FDA) approved products that allow a surgeon to do stapling anastomosis. However, while limited research has been done, additional research is still needed to learn more about the differences between suturing and stapling of such grafting anastomosis. Therefore, the purpose of this study was to investigate which suturing type (suturing vs. stapling) of coronary bypass grafting anastomosis provides a higher blood flow rate. After designing, developing, and programming an artificial heart capable of operating at different heart rates using a Lego® NXTTM robotic arm, we recorded the pressure on two gauges in order to calculate blood flow rate using Poiseuille’s Law. The results showed the suture anastomosis had a higher flow rate than the staple, because the staple slightly deformed the artery. Moreover, the results of this research follow Poiseuille’s Law in that a small reduction in an artery radius indeed can have a significant effect on the reduction the blood flow rate. Future research is recommended to learn more about how to improve the staple anastomosis in terms of improving blood flow rate in the grafted artery.

Photons from sunlight with energy slightly higher than that of the band gap of silicon create electric current within a photovoltaic (PV) cell. However, many photons from sunlight have either insufficient or excess energy. This study was conducted to find the effect of different photon transmission mediums on the temperature and voltage output of photovoltaic cells. Two different photovoltaic cells were tested under a 20-watt halogen lamp with 6 transmission mediums: 5% NaCl solution, 5% sugar solution, deionized (DI) water, canola oil, extra virgin olive oil (EVOO), and the control (air). It was hypothesized that the mediums with higher specific heats would result in relatively lower temperature increases, maintain higher voltages and have increased efficiencies compared to the mediums with lower specific heats. The voltage drop for EVOO, canola oil and air were higher than that of the aqueous solutions such as 5% sugar solution, 5% NaCl, or DI water. The results show an estimated increase of 5-6% in the performance of conventional photovoltaic cells by simply placing a layer of aqueous solution above the PV cell.

The traveling salesman problem (TSP) is a classic problem in optimization, frequently used for measuring the performance of optimization algorithms. The goal in solving the TSP is to determine the lowest-cost circuit through a set of cities on a graph. Ant colony optimization (ACO) algorithms, inspired by nature, use simulated ants that modify their environment through laying and removing pheromone, represented by weights on the edges of the graph connecting each city. In this study, a novel algorithm is developed, Multi-Colony System (MCS), which uses multiple colonies of simulated ants in combination to produce superior solutions to the TSP. In comparison with Ant Colony System (ACS), a standard well-performing ACO algorithm, MCS has displayed improved performance, producing tours up to 19.4% shorter than those of ACS in the same amount of time. The performance of MCS in this study presents potential advantages in applications beyond the TSP, including the ability of multiple colonies to both develop a greater number of solutions simultaneously and to more efficiently avoid local maxima in the search space.

Corn (maize, Zea mays L.) is one of the world’s most economically important grain crops. When exposed to heat, its starch-filled kernels pop and cook into puffs. The high demand for popcorn has spurred research to discover traits that dictate its idiosyncratic popping abilities. The purpose of this investigation is to study favorable popping traits and locate the regions on the maize chromosomes that show affiliation with such traits. Traits of interest include the kernel popping efficiency, the kernel popping expansion volume, the popping phenotype, and the average kernel size. In this study, kernel popping characteristics were assessed on 112 recombinant inbred corn lines from a large field population made by crossing B73 dent corn with popcorn line HP301. With a genetic marker linkage map available for the ten maize chromosomes, an analytical procedure called quantitative trait locus (QTL) mapping was done to determine chromosomal regions in the maize genome that may be important in the popping phenotype, based on the traits analyzed. QTL computer analysis revealed two QTLs for kernel popping efficiency on chromosomes 7 and 8, two additional QTLs for popping expansion volume on chromosomes 1 and 3, two QTLs for average kernel size on chromosomes 1 and 3, and one popping phenotype QTL on chromosome 2. The results of the QTL and maize phenotype correlation studies have relevance for better understanding the molecular basis of the popping phenotype. Furthermore, they could have practical applications in enhancing marketable popcorn.

Escherichia coli DegS is an integral inner membrane protein that breaks down incorrectly assembled proteins and helps regulate the s ? stress response pathway. When degS is deleted, approximately 200-fold more outer membrane vesicles (OMVs) are produced. As OMVs contain sections of the outer membrane and proteins from the periplasm, they may play a role in the virulence of E. coli. To test whether degS or OMVs play a role in uropathogenic E. coli (UPEC) virulence, we characterized a degS mutant. We found that the degS deletion did not affect the morphology of the bacterium, but did result in decreased virulence in vivo and in vitro. When we tested our mutant in a murine model of cystitis, mice infected with degS::cat bacteria had a 100-fold decrease in bacterial titers in the bladder at 24 hours post-infection. In vitro binding and invasion assays showed no difference in the ability to bind to host cells, but a significant decrease in the ability of mutant bacteria to invade cells. Together, these data suggest that degS deletion decreases the virulence of E. coli and that an increase in OMV production may be a detriment to virulence. Future studies can separate the role of degS and OMV production in UPEC virulence.

Music can have a profound effect on a person’s body, in that it may cause people to dance and move around, but does it have a direct and significant effect on a person’s heart rate if they are still? In this study, 24 high school students’ heart rates were recorded while listening to 6 selections of 6 different genres of music. The effect of different types of music was tested using heart rate monitors, data collection software, and music from free music archives. We found that music has a significant impact on heart rate. Average heart rates were significantly higher after listening to rock music, despite that selection having the slowest tempo of the six genres tested. Heart rates also significantly decreased after listening to classical music and significantly increased after listening to the subjects’ favorite musical selections. This indicates that someone may be able to decrease or increase their heart rate by simply listening to music. While significant patterns emerged, the study was limited, in that the order of the music was the same for every individual, the sample size was relatively small (n = 24), and heart rates were highly variable between subjects.