John F. Drazan

Experimental and credentialing capital: an adaptable framework for facilitating science outreach for underrepresented youth.

Increasing the numbers of black, latino and native youth in STEM careers is both an important way to reduce poverty in low income communities, and a contribution to the diversity of thought and experience that drives STEM research. But underrepresented youth are often alienated from STEM. Two new forms of social capital have been identified that can be combined to create a learning environment in which students and researchers can meet and explore an area of shared interest. Experimental capital refers to the intrinsic motivation that students can develop when they learn inquiry techniques for exploring topics that they feel ownership over. Credentialing capital denotes a shared interest and ability between all parties engaged in the experimental endeavor. These two forms of social capital form an adaptable framework for researchers to use to create effective outreach programs. In this case study sports biomechanics was utilized as the area of shared interest and understanding the slam dunk was used as experimental capital.

Using biomedical engineering and “hidden capital” to provide educational outreach to disadvantaged populations

A hands-on learning module called “Science of the Slam” is created that taps into the passions and interests of an under-represented group in the fields of Science, Technology, Engineering and Mathematics (STEM). This is achieved by examining the use of the scientific method to quantify the biomechanics of basketball players who are good at performing the slam dunk. Students already have an intrinsic understanding of the biomechanics of basketball however this “hidden capital” has never translated into the underlying STEM concepts. The effectiveness of the program is rooted in the exploitation of “hidden capital” within the field of athletics to inform and enhance athletic performance. This translation of STEM concepts to athletic performance provides a context and a motivation for students to study the STEM fields who are traditionally disengaged from the classic engineering outreach programs. “Science of the Slam” has the potential to serve as a framework for other researchers to engage under-represented groups in novel ways by tapping into shared interests between the researcher and disadvantaged populations.

A simple sensing mechanism for wireless, passive pressure sensors

We have developed a simple wireless pressure sensor that consists of only three electrically isolated components. Two conductive spirals are separated by a closed cell foam that deforms when exposed to changing pressures. This deformation changes the capacitance and thus the resonant frequency of the sensors. Prototype sensors were submerged and wirelessly interrogated while being exposed to physiologically relevant pressures from 10 to 130 mmHg. Sensors consistently exhibited a sensitivity of 4.35 kHz/mmHg which is sufficient for resolving physiologically relevant pressure changes in vivo. These simple sensors have the potential for in vivo pressure sensing.We have developed a simple wireless pressure sensor that consists of only three electrically isolated components. Two conductive spirals are separated by a closed cell foam that deforms when exposed to changing pressures. This deformation changes the capacitance and thus the resonant frequency of the sensors. Prototype sensors were submerged and wirelessly interrogated while being exposed to physiologically relevant pressures from 10 to 130 mmHg. Sensors consistently exhibited a sensitivity of 4.35 kHz/mmHg which is sufficient for resolving physiologically relevant pressure changes in vivo. These simple sensors have the potential for in vivo pressure sensing.

A case study for integrated STEM outreach in an urban setting using a do-it-yourself vertical jump measurement platform

The purpose of this study was to develop and deploy a low cost vertical jump platform using readily available materials for Science, Technology, Engineering, and Mathematics (STEM) education and outreach in the inner city. The platform was used to measure the jumping ability of participants to introduce students to the collection and analysis of scientific data in an engaging, accessible manner. This system was designed and fabricated by a student team of engineers as part of a socially informed engineering and design class. The vertical jump platform has been utilized in 10 classroom lectures in physics and biology. The system was also used in an after school program in which high school volunteers prepared a basketball based STEM outreach program, and at a community outreach events with over 100 participants. At present, the same group of high school students are now building their own set of vertical jump platform under the mentorship of engineering undergraduates. The construction and usage of the vertical jump platform provides an accessible introduction to the STEM fields within the urban community.

Reducing the effect of parasitic capacitance on implantable passive resonant sensors

Passive, LC resonators have the potential to serve as small, robust, low cost, implantable sensors to wirelessly monitor implants following orthopedic surgery. One significant barrier to using LC sensors is the influence on the sensors resonance of the surrounding conductive high permittivity media in vivo. The surrounding media can detune the resonant frequency of the LC sensor resulting in a bias. To mitigate the effects of the surrounding media, we added a “capping layer” to LC sensors to isolate them from the surrounding media. Several capping materials and thicknesses were tested to determine effectiveness at reducing the sensors interaction with the surrounding media. Results show that a 1 mm glass capping layer on the outer surfaces of the sensor was sufficient to reduce the effects of the media on sensor signal to less than 1%.

Strategies for the implementation of a simple, implantable sensor across different in vivo applications

The resonant behavior of passive sensor systems are affected electrical properties of nearby materials. Encapsulation of passive sensors allows them to be deployed across a wide range of applications without the need for significant redesign. The effects of different materials and media in close proximity to the sensor were compared between a sensor before and after encapsulation. The thickness of the encapsulating layer, (1.0 mm), was determined by defining the distance at which the change in resonant behavior reduced to 10% of the original value. Encapsulation reduced the variability and magnitude of the changes to the resonant frequency of the sensor induced by the surrounding media by 72% and 70% respectively. It also increased the average signal strength by 85% and reduced variability in signal strength between all treatments by 73%. Encapsulation resulted in a significant improvement of sensor performance and consistency across a range of media and packaging. Future work includes the incorporation of these findings into the batch fabrication process and the investigation of the effect of encapsulation using higher permittivity capping layers.

Force measurement across the patellofemoral joint using a smart patellar implant following a total knee arthroplasty

Osteoarthritis is one of the leading causes of chronic pain and disability in the United States. The gold standard to treat osteoarthritis of the knee is to perform a total knee replacement. Post-operatively, as high as 21% of total knee replacement patients experience moderate to severe anterior knee pain. The exact mechanism(s) of anterior knee pain remains unknown. Patellofemoral contact forces are believed to play a significant role in the mechanism of anterior knee pain. Yet, measuring contact forces in the patella has remained a challenge. We have developed a “smart patella” to measure force magnitudes and distributions across the patellofemoral joint. We have designed and conducted proof-of-concept experiments demonstrating that our novel force sensing system has the potential to be implanted into the patellofemoral joint space with minimal alterations to modern implant design. Once implanted, our sensors measure in real time, in vivo patellofemoral contact forces.

A wireless sensing system for continuous monitoring of intracompartmental pressures

Acute compartment syndrome (ACS) is a true orthopaedic emergency. The potential sequelae of an undiagnosed ACS include muscle necrosis, contracture, and in some cases amputation. We have developed a simple, wireless, passively-powered sensor that has the potential to provide continuous monitoring of intracompartmental pressure in vivo. This will allow clinicians to make an early diagnosis of ACS which is essential to preventing sequelae and unnecessary fasciotomies.