Researcher / Engineer
|Transatmospheric Vehicle Design||Engineering Dynamics||Differential Equations||Embedded Control|
|Aerospace Structural Analysis||Spaceflight Mechanics||Propulsion Systems||Aerodynamics|
|Thermal and Fluids Engineering||Electronic Instrumentation||Information Design||Fluid Dynamics|
|Boundary Layers and Heat Transfer||Numerical Computing||Mechanical Design||Nano-Spacecraft for Earth Science|
I managed a plethora of light and health research projects by supervising all data analysis and product development. Highlights include the invention of a Bluetooth wearable sensor that records light and motion, the creation of an Arduino-based lighting controller, and the development of 3D-printed parts for a light delivery apparatus designed for use with an fMRI device.
I developed a variety of designs and applications for our existing custom wearable light sensors. I conducted an assortment of research projects about lighting, coauthored peer-reviewed journal articles based on my research, and collaborated with researchers at other institutions (NASA, NIH, NIDA, ACS, NSMRL, GSA, UCSF, Duke University, the Icahn School of Medicine at Mount Sinai, etc…). I also mentored several of the students and interns at the center and helped them with their own assignments.
I calibrated the research equipment at the center, including custom wearable sensors, light goggles, and spectrometers. I also implemented a suite of MATLAB tools used to analyze research data.
At my internship, I spent my time interfacing with the manufacturing engineering team to add products into SAP ME, designing reports using Crystal Reports, and documenting process instructions for new systems. I also played a large part in improving the tracking system and process control to augment workflow performance.
As an intern in the Mechanical Engineering Department, I had the opportunity to assist with various projects by constructing 3D CAD models, creating technical drawings, engineering physical prototypes, conducting finite element analysis on models, and designing and testing watertight electronic enclosures.
I have been fortunate enough to work on a wide array of research topics from lemurs to Alzheimer's patients. My areas of interest and contributions have included analysis of sensor data, developing new and novel approaches for gathering data, and optimizing the storage and organization of collected data. Please explore some of the publications I have had the privilege to contribute to here.
If you would like to learn more about my publications I maintain profiles at ResearchGate and at Mendeley.
Light is the primary synchronizer of all biological rhythms, yet little is known about the role of the 24-hour luminous environment on nonhuman primate circadian patterns, making it difficult to understand the photic niche of the ancestral primate. Here we present the first data on proximate light-dark exposure and activity-rest patterns in free-ranging nonhuman primates. Four individuals each of five species of lemurs at the Duke Lemur Center (Eulemur mongoz, Lemur catta, Propithecus coquereli, Varecia rubra, and Varecia variegata variegata) were fitted with a Daysimeter-D pendant that contained light and accelerometer sensors. Our results reveal common as well as species-specific light exposure and behavior patterns. As expected, all five species were more active between sunrise and sunset. All five species demonstrated an anticipatory increase in their pre-sunrise activity that peaked at sunrise with all but V. rubra showing a reduction within an hour. All five species reduced activity during mid-day. Four of the five stayed active after sunset, but P. coquereli began reducing their activity about 2 hours before sunset. Other subtle differences in the recorded light exposure and activity patterns suggest species-specific photic niches and behaviors. The eventual application of the Daysimeter-D in the wild may help to better understand the adaptive evolution of ancestral primates. Am J Phys Anthropol 153:68-77, 2014. © 2013 Wiley Periodicals, Inc.
Background: Light therapy has shown great promise as a nonpharmacological method to improve symptoms associated with Alzheimer's disease and related dementias (ADRD), with preliminary studies demonstrating that appropriately timed light exposure can improve nighttime sleep efficiency, reduce nocturnal wandering, and alleviate evening agitation. Since the human circadian system is maximally sensitive to short-wavelength (blue) light, lower, more targeted lighting interventions for therapeutic purposes, can be used.
Methods: The present study investigated the effectiveness of a tailored lighting intervention for individuals with ADRD living in nursing homes. Low-level "bluish-white" lighting designed to deliver high circadian stimulation during the daytime was installed in 14 nursing home resident rooms for a period of 4 weeks. Light-dark and rest-activity patterns were collected using a Daysimeter. Sleep time and sleep efficiency measures were obtained using the rest-activity data. Measures of sleep quality, depression, and agitation were collected using standardized questionnaires, at baseline, at the end of the 4-week lighting intervention, and 4 weeks after the lighting intervention was removed.
Results: The lighting intervention significantly (P<0.05) decreased global sleep scores from the Pittsburgh Sleep Quality Index, and increased total sleep time and sleep efficiency. The lighting intervention also increased phasor magnitude, a measure of the 24-hour resonance between light-dark and rest-activity patterns, suggesting an increase in circadian entrainment. The lighting intervention significantly (P<0.05) reduced depression scores from the Cornell Scale for Depression in Dementia and agitation scores from the Cohen-Mansfield Agitation Inventory.
Conclusion: A lighting intervention, tailored to increase daytime circadian stimulation, can be used to increase sleep quality and improve behavior in patients with ADRD. The present field study, while promising for application, should be replicated using a larger sample size and perhaps using longer treatment duration.
At-Sea Trial of 24-h-Based Submarine Watchstanding Schedules with High and Low Correlated Color Temperature Light Sources
United States Navy submariners have historically lived with circadian disruption while at sea due to 18-h-based watchschedules. Previous research demonstrated that circadian entrainment improved with 24-h-based watchschedules. Twenty-nine male crew members participated in the study, which took place on an actual submarine patrol. The crew were exposed, first, to experimental high correlated color temperature (CCT = 13,500 K) fluorescent light sources and then to standard-issue fluorescent light sources (CCT = 4100 K). A variety of outcome measures were employed to determine if higher levels of circadian-effective light during on-watch times would further promote behavioral alignment to 24-h-based watchschedules. The high CCT light source produced significantly higher circadian light exposures than the low CCT light source, which was associated with significantly greater 24-h behavioral alignment with work schedules using phasor analysis, greater levels of sleep efficiency measured with wrist actigraphy, lower levels of subjective sleepiness measured with the Karolinska Sleepiness Scale, and higher nighttime melatonin concentrations measured by morning urinary 6-sulfatoxymelatonin/creatinine ratios. Unlike these diverse outcome measures, performance scores were significantly worse under the high CCT light source than under the low CCT light source, due to practice effects. As hypothesized, with the exception of the performance scores, all of the data converge to suggest that high CCT light sources, combined with 24-h watchschedules, promote better behavioral alignment with work schedules and greater sleep quality on submarines. Since the order and the type of light sources were confounded in this field study, the results should only be considered as consistent with our theoretical understanding of how regular, 24-h light-dark exposures combined with high circadian light exposures can promote greater behavioral alignment with work schedules and with sleep.
Objectives: Light therapy has shown promise as a nonpharmacological treatment to help regulate abnormal sleep-wake patterns and associated behavioral issues prevalent among individuals diagnosed with Alzheimer's disease and related dementia (ADRD). The present study investigated the effectiveness of a lighting intervention designed to increase circadian stimulation during the day using light sources that have high short-wavelength content and high light output.
Methods: Thirty-five persons with ADRD and 34 caregivers completed the 11-week study. During week 1, subjective questionnaires were administered to the study participants. During week 2, baseline data were collected using Daysimeters and actigraphs. Researchers installed the lighting during week 3, followed by 4 weeks of the tailored lighting intervention. During the last week of the lighting intervention, Daysimeter, actigraph and questionnaire data were again collected. Three weeks after the lighting intervention was removed, a third data collection (post-intervention assessment) was performed.
Results: The lighting intervention significantly increased circadian entrainment, as measured by phasor magnitude and sleep efficiency, as measured by actigraphy data, and significantly reduced symptoms of depression in the participants with ADRD. The caregivers also exhibited an increase in circadian entrainment during the lighting intervention; a seasonal effect of greater sleep efficiency and longer sleep duration was also found for caregivers.
Conclusions: An ambient lighting intervention designed to increase daytime circadian stimulation can be used to increase sleep efficiency in persons with ADRD and their caregivers, and may also be effective for other populations such as healthy older adults with sleep problems, adolescents, and veterans with traumatic brain injury.
SAP ME, Crystal Reports, Loftware, Microsoft Word/Excel/PowerPoint, Slack, Trello, JIRA
Siemens NX, SolidWorks, PTC Creo, Inventor, Cura, Slic3r, Pro/ENGINEER, FDM 3D Printing, FEA
HTML, CSS, Swift, GitHub, Raspberry Pi, Apple Xcode, Arduino
[...] I have had the pleasure of collaborating with Mr. Geoffery Jones on a joint research project between the US Navy and his former employer, the Lighting Research Center at Rensselaer Polytechnic Institute, Troy, NY. During this time period I met with Mr. Jones multiple times in person and had a multiple opportunities to work directly with him on the analysis and manuscript preparation for a complicated US Navy led field trial. Mr. Jones demonstrated flexibility, ingenuity, and optimism as we conducted analysis using novel research techniques integrating biomedical, engineering, statistics, and military operational concepts to lead to a product that we are currently attempting to publish in a peer-reviewed biomedical journal.
As a US Naval Academy graduate, former Navy submarine line officer qualified as naval nuclear engineer, and currently a US Navy physician, I have had the privilege to work with many highly talented people, both military and civilian. Mr. Jones is among the top 5 percent of people that I have evaluated.
I hired Geoffrey to help implement our new SAP manufacturing systems capabilities. Geoffrey did an outstanding job in all areas that included; selection and evaluation of software, developing functional specifications, master data configuration and programming of custom reports. In addition to his information technology internship, Geoffrey demonstrated a willingness to learn and worked closely with our mechanical, engineering and operations teams. I can definitely recommend Geoffrey for any organization. He is a passionate professional with solid technical and leadership qualities.
I had the pleasure of working alongside Geoffrey during the implementation of SAP ME software. His technical skill and attention to detail were invaluable to the success of the initiative. I would highly recommend Geoffrey and would personally hope for the opportunity to work with him again in the future.