Matching Items (6)
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- All Subjects: Imaging
- Creators: Stabenfeldt, Sarah
- Creators: Electrical Engineering Program
- Status: Published
Description
Oxygen delivery is crucial for the development of healthy, functional tissue. Low tissue oxygenation, or hypoxia, is a characteristic that is common in many tumors. Hypoxia contributes to tumor malignancy and can reduce the success of chemotherapy and radiation treatment. There is a current need to noninvasively measure tumor oxygenation or pO2 in patients to determine a personalized treatment method. This project focuses on creating and characterizing nanoemulsions using a pO2 reporter molecule hexamethyldisiloxane (HMDSO) and its longer chain variants as well as assessing their cytotoxicity. We also explored creating multi-modal (MRI/Fluorescence) nanoemulsions.
ContributorsGrucky, Marian Louise (Author) / Kodibagkar, Vikram (Thesis director) / Rege, Kaushal (Committee member) / Stabenfeldt, Sarah (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2013-05
Description
Traumatic brain injury (TBI) is a major concern in public health due to its prevalence and effect. Every year, about 1.7 million TBIs are reported [7]. According to the According to the Centers for Disease Control and Prevention (CDC), 5.5% of all emergency department visits, hospitalizations, and deaths from 2002 to 2006 are due to TBI [8]. The brain's natural defense, the Blood Brain Barrier (BBB), prevents the entry of most substances into the brain through the blood stream, including medicines administered to treat TBI [11]. TBI may cause the breakdown of the BBB, and may result in increased permeability, providing an opportunity for NPs to enter the brain [3,4]. Dr. Stabenfeldt's lab has previously established that intravenously injected nanoparticles (NP) will accumulate near the injury site after focal brain injury [4]. The current project focuses on confirmation of the accumulation or extravasation of NPs after brain injury using 2-photon microscopy. Specifically, the project used controlled cortical impact injury induced mice models that were intravenously injected with 40nm NPs post-injury. The MATLAB code seeks to analyze the brain images through registration, segmentation, and intensity measurement and evaluate if fluorescent NPs will accumulate in the extravascular tissue of injured mice models. The code was developed with 2D bicubic interpolation, subpixel image registration, drawn dimension segmentation and fixed dimension segmentation, and dynamic image analysis. A statistical difference was found between the extravascular tissue of injured and uninjured mouse models. This statistical difference proves that the NPs do extravasate through the permeable cranial blood vessels in injured cranial tissue.
ContributorsIrwin, Jacob Aleksandr (Author) / Stabenfeldt, Sarah (Thesis director) / Bharadwaj, Vimala (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Imaging using electric fields could provide a cheaper, safer, and easier alternative to the standard methods used for imaging. The viability of electric field imaging at very low frequencies using D-dot sensors has already been investigated and proven. The new goal is to determine if imaging is viable at high frequencies. In order to accomplish this, the operational amplifiers used in the very low frequency imaging test set up must be replaced with ones that have higher bandwidth. The trade-off of using these amplifiers is that they have a typical higher input leakage current on the order of 100 compared to the standard. Using a modified circuit design technique that reduces input leakage current of the operational amplifiers used in the imaging test setup, a printed circuit board with D-dot sensors is fabricated to identify the frequency limitations of electric field imaging. Data is collected at both low and high frequencies as well as low peak voltage. The data is then analyzed to determine the range in intensity of electric field and frequency that this circuit low-leakage design can accurately detect a signal. Data is also collected using another printed circuit board that uses the standard circuit design technique. The data taken from the different boards is compared to identify if the modified circuit design technique allows for higher sensitivity imaging. In conclusion, this research supports that using low-leakage design techniques can allow for signal detection comparable to that of the standard circuit design. The low-leakage design allowed for sensitivity within a factor two to that of the standard design. Although testing at higher frequencies was limited, signal detection for the low-leakage design was reliable up until 97 kHz, but further experimentation is needed to determine the upper frequency limits.
ContributorsLin, Richard (Co-author) / Angell, Tyler (Co-author) / Allee, David (Thesis director) / Chung, Hugh (Committee member) / Electrical Engineering Program (Contributor) / W. P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Readout Integrated Circuits(ROICs) are important components of infrared(IR) imag
ing systems. Performance of ROICs affect the quality of images obtained from IR
imaging systems. Contemporary infrared imaging applications demand ROICs that
can support large dynamic range, high frame rate, high output data rate, at low
cost, size and power. Some of these applications are military surveillance, remote
sensing in space and earth science missions and medical diagnosis. This work focuses
on developing a ROIC unit cell prototype for National Aeronautics and Space Ad
ministration(NASA), Jet Propulsion Laboratory’s(JPL’s) space applications. These
space applications also demand high sensitivity, longer integration times(large well
capacity), wide operating temperature range, wide input current range and immunity
to radiation events such as Single Event Latchup(SEL).
This work proposes a digital ROIC(DROIC) unit cell prototype of 30ux30u size,
to be used mainly with NASA JPL’s High Operating Temperature Barrier Infrared
Detectors(HOT BIRDs). Current state of the art DROICs achieve a dynamic range
of 16 bits using advanced 65-90nm CMOS processes which adds a lot of cost overhead.
The DROIC pixel proposed in this work uses a low cost 180nm CMOS process and
supports a dynamic range of 20 bits operating at a low frame rate of 100 frames per
second(fps), and a dynamic range of 12 bits operating at a high frame rate of 5kfps.
The total electron well capacity of this DROIC pixel is 1.27 billion electrons, enabling
integration times as long as 10ms, to achieve better dynamic range. The DROIC unit
cell uses an in-pixel 12-bit coarse ADC and an external 8-bit DAC based fine ADC.
The proposed DROIC uses layout techniques that make it immune to radiation up to
300krad(Si) of total ionizing dose(TID) and single event latch-up(SEL). It also has a
wide input current range from 10pA to 1uA and supports detectors operating from
Short-wave infrared (SWIR) to longwave infrared (LWIR) regions.
ing systems. Performance of ROICs affect the quality of images obtained from IR
imaging systems. Contemporary infrared imaging applications demand ROICs that
can support large dynamic range, high frame rate, high output data rate, at low
cost, size and power. Some of these applications are military surveillance, remote
sensing in space and earth science missions and medical diagnosis. This work focuses
on developing a ROIC unit cell prototype for National Aeronautics and Space Ad
ministration(NASA), Jet Propulsion Laboratory’s(JPL’s) space applications. These
space applications also demand high sensitivity, longer integration times(large well
capacity), wide operating temperature range, wide input current range and immunity
to radiation events such as Single Event Latchup(SEL).
This work proposes a digital ROIC(DROIC) unit cell prototype of 30ux30u size,
to be used mainly with NASA JPL’s High Operating Temperature Barrier Infrared
Detectors(HOT BIRDs). Current state of the art DROICs achieve a dynamic range
of 16 bits using advanced 65-90nm CMOS processes which adds a lot of cost overhead.
The DROIC pixel proposed in this work uses a low cost 180nm CMOS process and
supports a dynamic range of 20 bits operating at a low frame rate of 100 frames per
second(fps), and a dynamic range of 12 bits operating at a high frame rate of 5kfps.
The total electron well capacity of this DROIC pixel is 1.27 billion electrons, enabling
integration times as long as 10ms, to achieve better dynamic range. The DROIC unit
cell uses an in-pixel 12-bit coarse ADC and an external 8-bit DAC based fine ADC.
The proposed DROIC uses layout techniques that make it immune to radiation up to
300krad(Si) of total ionizing dose(TID) and single event latch-up(SEL). It also has a
wide input current range from 10pA to 1uA and supports detectors operating from
Short-wave infrared (SWIR) to longwave infrared (LWIR) regions.
ContributorsPraveen, Subramanya Chilukuri (Author) / Bakkaloglu, Bertan (Thesis advisor) / Kitchen, Jennifer (Committee member) / Long, Yu (Committee member) / Arizona State University (Publisher)
Created2019
Description
The NASA Psyche Iron Meteorite Imaging System (IMIS) is a standalone system created to image metal meteorites from ASU’s Center for Meteorite Studies’ collection that have an etched surface. Meteorite scientists have difficulty obtaining true-to-life images of meteorites through traditional photography methods due to the meteorites’ shiny, irregular surfaces, which interferes with their ability to identify meteorites’ component materials through image analysis. Using the IMIS, scientists can easily and consistently obtain glare-free photographs of meteorite surface that are suitable for future use in an artificial intelligence-based meteorite component analysis system. The IMIS integrates a lighting system, a mounted camera, a sample positioning area, a meteorite leveling/positioning system, and a touch screen control panel featuring an interface that allows the user to see a preview of the image to be taken as well as an edge detection view, a glare detection view, a button that allows the user to remotely take the picture, and feedback if very high levels of glare are detected that may indicate a camera or positioning error. Initial research and design work were completed by the end of Fall semester, and Spring semester consisted of building and testing the system. The current system is fully functional, and photos taken by the current system have been approved by a meteorite expert and an AI expert. The funding for this project was tentatively capped at $1000 for miscellaneous expenses, not including a camera to be supplied by the School of Earth and Space Exploration. When SESE was unable to provide a camera, an additional $4000 were allotted for camera expenses. So far, $1935 of the total $5000 budget has been spent on the project, putting the project $3065 under budget. While this system is a functional prototype, future capstone projects may involve the help of industrial designers to improve the technician’s experience through automating the sample positioning process.
ContributorsBaerwaldt, Morgan Kathleen (Author) / Bowman, Cassie (Thesis director) / Kozicki, Michael (Committee member) / School of Art (Contributor) / Electrical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Time-Lapse Visualization of Microglia Cell Processes using Fluorescent Miniature (Miniscope) Imaging
Description
In the United States, an estimated 2 million cases of traumatic brain injury (TBI) resulting in more than 50,000 deaths occur every year. TBI induces an immediate primary injury resulting in local or diffuse cell death in the brain. Then a secondary injury occurs through neuroinflammation from immune cells in response to primary injury. Microglia, the resident immune cell of the central nervous system, play a critical role in neuroinflammation following TBI. Microglia make up 10% of all cells in the nervous system and are the fastest moving cells in the brain, scanning the entire parenchyma every several hours. Microglia have roles in both the healthy and injured brain. In the healthy brain, microglia can produce neuroprotective factors, clear cellular debris, and organize neurorestorative processes to recover from TBI. However, microglia mediated neuroinflammation during secondary injury produces pro-inflammatory and cytotoxic mediators contributing to neuronal dysfunction, inhibition of CNS repair, and cell death. Furthermore, neuroinflammation is a prominent feature in many neurodegenerative diseases such as Alzheimer’s, and Parkinson’s disease, of which include overactive microglia function. Microglia cell morphology, activation, and response to TBI is poorly understood. Currently, imaging microglia can only be performed while the animal is stationary and under anesthesia. The Miniscope technology allows for real-time visualization of microglia in awake behaving animals. The Miniscope is a miniature fluorescent microscope that can be implanted over a craniectomy to image microglia. Currently, the goals of Miniscope imaging are to improve image quality and develop time-lapse imaging capabilities. There were five main sub-projects that focused on these goals including surgical nose cone design, surgical holder design, improved GRIN lens setup, improved magnification through achromatic lenses, and time-lapse imaging hardware development. Completing these goals would allow for the visualization of microglia function in the healthy and injured brain, elucidating important immune functions that could provide new strategies for treating brain diseases.
ContributorsNelson, Andrew Frederick (Author) / Stabenfeldt, Sarah (Thesis director) / Lifshitz, Jonathan (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05