Schedule of Events

Two recent methodologies use ultrasound images to measure tendon strain in vivo.  Tendon Elongation (TE) method measures distances between a fixed anatomical landmark and a marker on the images (Malliaras et al., 2013). Acoustoelasticity (AE) utilizes an algorithm to track the pixels in an ultrasound video and generates a strain value over time (Kobayashi et al., 2010). The purpose of this study is to compare the strain values using the TE and AE using Echosoft software (Echometrix, Madison, WI). Eight male participants were strapped into a Biodex System 3 isokinetic dynamometer to isolate preferred leg knee extension.  A thin aluminum strip was affixed approximately 30 mm distal to their inferior patellar apex as a reference marker.  Subjects completed a set of eight 3-second ramp-up maximum knee extension isometric contractions with ultrasound video (Terason 3200 at 25 Hz) collected simultaneously. TE values were determined using MicroDicom software while AE strain values were computed using Echosoft.  The mean percent strain values were significantly different between methodologies: 8.9%, 15.2%, 16.8%, 17.3% measured by TE and 4.1%, 6.2%, 7.9%, and 9.6% measured by AE at 25%, 50%, 75%, and 100% peak strain, respectively (p<0.05). There was a significant relationship in mean strain percentages between TE and AE at 25% of peak strain with TE being longer (r=0.655, p=0.006) and a trend at 50% of peak strain with TE being larger (r=0.479, p=0.0603).  The differences in these methods likely relate to AE investigating a region of interest while TE computes using an overall length.

As laser and microwave technologies continue to develop they show promise for applications in wireless power beaming over long distances. It is estimated that we can achieve 29% efficiency from power plant to power grid using 1.5 micron near infrared (NIR) lasers mounted on aerostats using only existing technology. While not intended to be a permanent solution, deployed nodes could act as wireless links thus completing the power grid at any point where it may fail, including the scenario in which the system is down but the power plants remain operational such as after a hurricane or earthquake. While most of the technology is currently mature, the tethers required to transmit the power from aerostat to mooring platform are not currently developed in such a way that would be applicable to be suspended from 1.4 or 4.6 km. As such, the standard copper wires can be replaced with fiber optics where the tethered aerostats then act as waveguides rather than repeaters. In addition to the tether, the photovoltaic runs into some issues. Silicon is not particularly sensitive to near infrared radiation so special cells of Indium Gallium Arsenide Phosphide (InGaAsP) can be employed due to their increased efficiency in NIR capture, especially when used in optical concentrators. These technologies, while currently the subject of academics and semiconductor physicists, can be utilized to make tethered wireless power transmission nodes to mediate power deprivation in the event of wide scale outages.   

The immune system plays a crucial role in determining the success of implantation of a tissue-engineered construct.  In the case of rejection, the body's immune response is largely responsible.  The system first works to recognize the construct, which is labeled as non-self, and then develop an appropriate response, typically an inflammatory response, which cascades into the rejection of the construct.  Recently, attention has been turned toward suppressing the rejection of antibodies through the use of anti-inflammatory drugs and enhancing the integration of tissue-engineered constructs with native tissue by using growth factors.  Here, the effects of vascular endothelial growth factor (VEGF) and Interleukin-10 (IL-10)--a substance that has previously shown an ability to promote cell proliferation and a known anti-inflammatory drug, respectively--were examined using 3T3 fibroblast cells.  It is expected that when tested in tandem, VEGF will promote cell proliferation, while IL-10 will have no effect on overall cell growth and will not demonstrate cytotoxicity to the cells though it is also expected that in the event of an inflammatory response the drug should function as a suppressant.  Further studies can be used to examine the effect of VEGF and IL-10 on fibroblasts with integration into a scaffold and further study the ability of the cells to integrate with native tissues in the body.

Western Fence Lizards (Sceloporus occidentalis) can voluntarily lose their tails to avoid predation, but because they store fat in their tails, this may lower the lizards’ survivability. And because they are territorial, tail loss may also carry social costs: in some other lizards, the loss of tails in males lowered their social status among potential mates. We conducted this study to determine if tail loss in males affects social status or running biomechanics. We collected data from males and females from May to August in 2014 and 2015. We marked them for identification in the field and collected a GPS point each time one was found. We mapped individual territories using these points in GIS software. In total, we found points for 29 males and 22 females. In June of 2015, we brought seven males into the lab. We measured their bite force, sprint speed, and morphology, and took high-speed videos of each lizard sprinting. We removed tails from four of the males and measured and video recorded their sprint speed again. Afterwards, we returned all lizards to their original locations. Our sprint data suggest that the males who had a high initial sprint speed run slower after tail loss (possibly a social cost in defending territories), but those who did not run as fast before tail loss were not affected. Initial analysis of high-speed video revealed that after tail loss, lizards appeared to shift their center of mass forward, presumably because of the lack of counterweight in the tail.

The vitality of honey bees is essential for crop pollination and honey production. The recent rapid decline of the global honey bee population, termed “Colony Collapse Disorder”, has not been attributed to a single cause within the scientific research community. One factor that has been considered is the confinement of honey bees to monoculture crops, as seen in commercial pollination services, rather than allowing bees to forage on a diverse diet. This dietary restriction can alter the community of associated bacteria within the gut. Since honey bees express one third of the innate immunity genes of most insects, the antimicrobial producing microbes that reside in the honey stomach may contribute to each bee’s ability to ward off invading pathogens. The aim of the present study is to compare the antimicrobial production by the bacteria cultured from the honey stomach of honey bees that forage on a diverse or monoculture diet (citrus, raspberry, or avocado). Honey bees were collected from hives exposed to one of the two diet types. Honey stomachs were excised, homogenized, and plated for isolation of lactic acid bacteria on MRS agar at 35°C. To determine antimicrobial production, bacterial isolates were screened for inhibition of Bacillus subtilis. Bacteria isolated from honey bees with a diverse diet exhibited more antimicrobial production against B. subtilis than those from bees with a monoculture diet. These results support the hypothesis that more antimicrobial-producing bacteria reside in the honey stomachs of bees that forage on a diverse diet than on a monoculture diet.

Computational Complexity Theory provides techniques to determine the difficulty of solving certain problems algorithmically. Problems are organized into classes of problems with similar difficulty. One of these classes, NP-Complete (NPC), is of highest interest, as solving one of these problems quickly will imply other problems can be solved quickly as well. Graph Coloring, that is, properly coloring vertices of a graph such that no two adjacent vertices are the same color, is one of the problems in NPC. The focus of this project is to understand and to prove that Graph Coloring is NPC. Doing this required an understanding of Complexity Theory, involving the comprehension of important Lemmas, in addition to the ability to prove them. Additionally, it was necessary to study how to implement Complexity Theory on actual problems. Then, a study of the proof showing Graph Coloring is NPC was done, using the knowledge of Complexity Theory acquired throughout this research. This proof has been thoroughly understood and explained in a way different then the original, in addition to correcting an error in the studied proof.