VIRTUAL STUDENT SCHOLARS SYMPOSIUM 2020 PRESENTATIONS

Engineering - Poster Presentations

High School Division

Development of Novel Cerebral Aneurysm Embolization Method via Injection of Pluronic F-127 Multiblock Copolymer Hydrogel
Finnur T Christianson, Ponte Vedra High School

Endovascular embolization is a recently developed minimally invasive technique used for
treatment of cerebral aneurysms. However, this technique is limited by the packing density achieved by the coils, and currently results in a high recurrence rate of 17%. Hydrogels are networks of polymer chains that are biocompatible and highly absorbent, and therefore can be injected directly into aneurysms to occlude the vessel. In this study, I therefore developed a novel aneurysm occlusion technique through injection of a shear thinning hydrophilic triblock copolymer, Pluronic F-127. Pluronic F-127 hydrogels were synthesized at concentrations of 20%, 25% and 30% w/v, and contrast agent iopromide was added at concentrations of 20% and 30% v/v to 20% F-127 for angiography. To increase rigidity, 1% and 5% w/v PF-127 multiblock copolymer was added to F-127 to achieve final hydrogel concentration of 25%. Various rheological techniques, including amplitude sweep, single frequency, and temperature dependent tests were conducted to determine the viscoelastic range and elastic modulus as a function of temperature of each gel. The addition of multiblock copolymer PF-127 at concentrations of 1% and 5% resulted in occlusion times of 31 minutes and 61 minutes, respectively. The 5% multiblock copolymer showed a nearly fivefold improvement over the occlusion time of 25% w/v F-127 without multiblock copolymer (occlusion time
of 13 minutes). Due to their biocompatibility and absorbent properties, coupled with high elastic moduli and shear thinning properties, hydrogel injection for aneurysm embolization has great potential for intracranial aneurysm treatment.

Grover-Based Quantum Algorithm and Oracle Circuit Design for Solving the Bounded Knapsack Problem
Wenjun Hou, Jesuit High School

The purpose of this project was to design and implement a quantum algorithm to solve the Bounded Knapsack Problem more efficiently than classical methods, implement the algorithm with a real quantum oracle circuit design, and test the design on a quantum simulator, which is constrained by a 30-qubit limitation. The Bounded Knapsack Problem is an optimization problem that is widely used in industry and holds potential in developing post-quantum cryptosystems. This project presents the first such algorithm and oracle circuit design to solve the Bounded Knapsack Problem on quantum computers. This project also features an analysis of the quantum gate cost and overall time complexity analysis, which have not been done widely in quantum literature. The proposed procedure leverages repeated calls to Grover’s Search Algorithm, a quantum algorithm that can search an unsorted database using fewer queries than classical methods. The Grover Searches are called using the proposed Quantum Knapsack Oracle, which contains three modules: Bounds Checking, Weight Checking, and Profit Checking. Many arithmetic circuits had to be custom-designed due to the lack of suitable functions in the existing Q# libraries. The Knapsack Oracle was successfully implemented in the quantum language Q# and tested for correctness using the QDK local simulator. The gate cost of the overall quantum circuit was evaluated using the standard developed by Maslov. The time complexity of the algorithm was compared to existing classical solutions, including dynamic programming, and proven to demonstrate significant advantages for both single and multi-dimensional Knapsack Problems.

Undergraduate Division

Use of Recycled Waste Oils to Rejuvenate Asphalt Pavements
Odette Dominguez, Manhattan College

When exposed to air, asphalt binder contained in asphalt pavements oxidizes, which causes it to harden and decreases its durability. This presentation discusses the use of rejuvenators that reverse the harmful effects of oxidation and restore the asphalt binder’s original properties. Thin-films of asphalt binder were exposed to high temperatures in a laboratory oven to simulate years of aging that would be caused by oxidation. While typical rejuvenators are hydrocarbon based and are not environmentally friendly, these experiments studied the effectiveness of using recycled oils as rejuvenators, including waste cooking and recycled motor oil. The amount of oxidation was quantified by measuring the viscosity of the asphalt binder. The thin-films of asphalt binder were oxidized by exposure to 325 o F for times varying from 6 to 72 hours. The
original unaged asphalt binder had a viscosity of 1.2 Pa-s and after 72 hours of aging, it increased to 68 Pa-s. There was a clear correlation between the aging time and viscosity. Additionally, the nonlinear differential dynamics model was fit to the data. After calculating the viscosity of the aged asphalt binder and the viscosity of the different recycled oils, a blending equation was used to predict the rejuvenator dosage needed to lower the viscosity of the aged asphalt back to its original value. After measuring the viscosity of the rejuvenated asphalt binder it was determined that both of the recycled oils can be successfully used as rejuvenators and that the blending equation can accurately predict the required rejuvenator dosage.

Graduate Division

Ultrasound-Assisted Bioprinting of Anisotropic 3D Cellular Constructs
Parth Chansoria, North Carolina State University

A critical consideration in tissue engineering (TE) is to biomimic the micro-structural organization (anisotropy) of cells and cell-secreted extracellular matrix found in natural tissues that is essential to their function. Current TE approaches such as 3D bioprinting lag in achieving this anisotropy due to the intrinsic homogeneity of the cell distribution in bioinks. Herein, we have developed a 3D bioprinting process that uses ultrasound to organize cells within bioprinted tissues. Through multiphysics modeling and experimental design, we investigate the effect of ultrasound frequency (0.71, 1, 1.5, 2 MHz) on alignment characteristics of human adipose stem cells (hASC) within chemically-crosslinked alginate and photo-crosslinked GelMA constructs. Results show that cell array-spacing decreases with increasing frequency (p < 0.001), array width decreases with increasing frequency and amplitude (p < 0.01), and viability is slightly reduced within high viscosity alginate matrix due to increased drag forces. We then demonstrate 3D-bioprinting of a multi-layered knee meniscus, annulus fibrosus or heart tissue constructs with relevant circumferential or crisscross cell organization. Furthermore, we demonstrate attachment and proliferation of hASC along their organized patterns within the bioprinted constructs, thereby biomimicking the natural tissue characteristics.

Delivery of DNA by Carbon Nanofiber Arrays and Tracking of Gene Expression
Jessica M Morgan, University of Chicago

We have pioneered the use of vertically aligned carbon nanofiber (VACNF) arrays for the purpose of delivering DNA encoded probes and performed transient transformation in plants. The VACNFs permeabilize leaf tissue transiently to allow small molecules in without causing a detectable stress responsor cell toxicity (Davern et al., 2016). Our fiber array system overcomes challenges of crossing cell wall and plasma membrane, there is no release of cargo necessary since it acts by capillary mechanism, and we can target specific cells by adjusting fiber size parameters. Using confocal microscopy, we present evidence that DNA-encoded fluorescent protein probes and markers can readily be delivered to roots, shoots, flowers, leaves, and other organs of three plant species: arabidopsis, poplar, and tomato. We used these probes to measure changes in cGMP in response to exogenous application of gibberellic acid and the sulfated pentapeptide phytosulfokine. Using this system, it is possible to transiently transform epidermal cells and image intact plants over time. By examining the plant without destroying the integrity of the system, this approach will provide a more physiologically accurate picture of signaling pathways than most other studies that rely on detached tissues.

VIRTUAL STUDENT SCHOLARS SYMPOSIUM 2020 PRESENTATIONS

Engineering - Poster Presentations

High School Division

Undergraduate Division

Graduate Division

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