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Layer-by-Layer Printing of Alginate for Cancer Cell Migration Assays
Yana Sichar, Alexander Roth, Emily Serbinowski, and Kyeong Nam Yu
Rapid assessment of the invasion potential of various cancers in three-dimensional (3D) cell culture via layer-by-layer printing of cells encapsulated in hydrogels has been studied. Microarray bioprinting technology on microwell chips has been explored to create 3D cancer-like tissue structures and study cancer cell migration. Alginate, a negatively charged biopolymer, forms hydrogels via ionic crosslinking. Oxy-methacrylated alginate (OMA) is polymerized via near-ultraviolet light in the presence of photoinitiators. Our goal is to demonstrate rapid creation of cancer tissuelike structures via microarray 3D-bioprinting and develop a high-throughput, 3D cancer cell migration assay. To achieve this goal, layer-by-layer cell culture conditions were optimized in OMA by varying exposure time, photoinitiator concentration, alginate concentration, and cell seeding density. 3D cancer cell migration was demonstrated by printing two layers of hydrogels into the microwells: the bottom layer with a mixture of alginate and matrigel, and the top layer with Hep3B cells in alginate. Printed cells were cultured for fourteen days to investigate cell migration in 3D. As a result, it was found that migration of liver cancer cells needs to be extended for longer times. Also, bidirectional migration potential and leaching of additives (e.g., Matrigel) over time from alginate matrices will be investigated.
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Design and Fabrication of a Microfluidic Device using a 3D Printer
Aaron Smith
The goal of this work was to design and implement a microfluidic mixer-based chemical reactor using a 3-D printer. Microfluidic devices are very useful for processes that use expensive reactants or require a high level of control, and we hypothesize that the ability to develop a prototype using a 3-D printer would lower their costs and help overcome some of the limitations of soft-lithography based devices. One-level and two-level designs were made using SolidWorks® software, and various stages of the model were printed on Objet® and FDM® printers. The Objet printer offers the advantage of printing a prototype using a transparent polymer. However, initial trials did not result in the printing of a functional prototype, and preliminary simulations suggest that changing the design features results in less efficient mixing. The FDM printer is capable of printing a functional prototype, but the polymer used is opaque. This hinders the live-imaging capabilities of the experimental analysis of the mixing in the device. The design features and selection of polymeric materials are currently being evaluated and optimized, and future research will experimentally evaluate mixing of fluids in these devices.
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How does educational opportunities influence decisions for Nigerian girls and the society?
Shalonda Swanson
This paper raises questions about educational opportunities for Nigerian girls to understand if traditional Islamic or Western education influence the girls on various factors; including, their religious connections, optimism for their future, and the value in Islamic education compared to Western education. To discuss the current status of the country the paper discusses the historical underlying factors that influenced Nigeria's policies for educational opportunities for girls. Nigeria has struggled with gender disparities that disproportionately provided educational opportunities for boys at an increased rate compared to girls. This research reports the traditional values that restricted girls' access to education and the structural changes that permitted the enrollments of girls in education aside from traditional Islamic education. In addition, the paper illustrates Nigerian's economic changes that implemented different structures within society which influenced the educational opportunities for Nigerian girls.
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How Dry is the Lower Atmosphere: Finding Relations Between Various Moments in the Atmospheric Boundary Layer
Vladimir Sworski
The Atmospheric Boundary Layer (ABL), consisting of the bottom few kilometers of the troposphere, is a highly turbulent region with strong mixing of moisture and winds. This region's activity is driven by thermals, which rise to the top of the boundary layer and thicken it through entrainment of warm air from above. To better predict the behavior of the ABL, a good understanding of the distribution of heat, moisture and momentum is important. In this study, we use a high resolution computer model (LES) to determine those distributions. We were able to reproduce observations when using a temporal averaging that is close to the algorithm used in the observations. However, we found significant discrepancies between temporal and spatial averaging of the same model results. For example, skewness and kurtosis have a strong relationship that helps describe the shape of the distribution. It showed that there is significantly fewer points with both positive skewness and kurtosis. This is related to a strong change that is also present between the temporal and spatial third moments. A study of these differences was also conducted.
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Designing Genes that Encode Proteins for Biomedical Applications
Isaiah Traben
DNA is a crucial component of all known life. It encodes in genes the structure of the proteins necessary to perform many of the functions in a cell. Proteins are biological polymers consisting of a chain of amino acids. The specific sequence of the amino acids determines the structure and therefore function of the protein. The sequence of the amino acids of a protein is coded in DNA via triplets of the nucleotide bases known as codons, which each can represent only one amino acid. However, an amino acid can be represented by more than one codon, so there are many combinations of DNA that can code for any given protein. The efficiency of expressing a protein from a gene can be affected by the DNA sequence, so to optimize protein production, we want an optimal sequence of DNA. Particularly, we would like to be able to design ab initio, optimized genes that code for protein-based materials for biological applications. We are working to develop a computer program to generate DNA code from an amino acid sequence. The ultimate goal is to optimize the sequence by using codons in an efficient way and removing unwanted patterns in the gene.
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Light Scattering Characterization of Elastin-Like Polypeptide Trimer Micelles
Ilona Tsuper, Daniel Terrano, and Adam Maraschky
Elastin-Like Polypeptides (ELP) can be used to form thermo-reversible vehicles for drug delivery systems. The ELP nanoparticles are composed of three-armed star polypeptides. Each of the three arms extending from the negatively charged foldon domain includes 20 repeats of the (GVGVP) amino acid sequence. The ELP polymer chains are soluble at room temperature and become insoluble at the transition temperature (close to 50 oC), forming micelles. The size and shape of the micelle is dependent on the temperature and the pH of solution, along with the concentration of the Phosphate Buffered Saline (PBS) solvent. The technique of Depolarized Dynamic Light Scattering (DDLS) was employed to study the structure and dynamics of micelles at 62 oC; the solution was maintained at an approximate pH level of 7.3 - 7.5, while varying the concentration of the solvent (PBS). At low salt concentrations (< 15 mM), the micellar size is not very reproducible due to unstable pH levels, arising from low buffer concentration. At intermediate salt concentrations (15 - 60 mM), the system formed spherically-shaped micelles exhibiting a steady growth in the hydrodynamic radius (Rh) from 10 to 21 nm, with increasing PBS concentration. Interestingly, higher salt concentrations (> 60 mM) displayed an apparent elongation of the micelles evident by a significant VH signal, along with a surge in the apparent Rh. A model of micelle growth (and potentially elongation) with increase in salt concentration is considered.
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Light Scattering Study of Mixed Micelles Made from Elastin-Like Polypeptide Linear Chains and Trimers
Ilona Tsuper, Daniel Terrano, and Adam Maraschky
Temperature sensitive nanoparticles (E20F) were generated from a construct of three chains of Elastin- Like Polypeptides (ELP) linked to a negatively charged foldon domain. This ELP system was mixed at different ratios with a single linear chain of ELP (H40L) which was deprived of the foldon domain. The mixed system is soluble at room temperature and at a transition temperature will form swollen micelles with the hydrophobic linear chains hidden inside. This system was studied using Depolarized Dynamic Light Scattering (DDLS) and Static Light Scattering (SLS) to model the size, shape, and internal structure of the mixed micelles. The mixed micelle in equal parts of E20F and H40L show a constant apparent hydrodynamic radius of 40-45 nm at the concentration window from 25:25 to 60:60 μM (1:1 ratio). At a fixed 50 μM concentration of the E20F with varying H40L concentrations from 5 to 80 μM, a linear growth in the hydrodynamic radius is seen from about 11 to about 62 nm, along with a 1000-fold increase in VH signal. A possible simple model explaining the growth of the mixed micelles is considered. Lastly, the VH signal can indicate elongation in the geometry of the particle or could possibly be a result from anisotropic properties from the core of the micelle. Static Light Scattering was used to study the molecular weight, and the radius of gyration of the micelle to help identify the structure and morphology of mixed micelles and the tangible cause of the VH signal.
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Bioinformatic Analysis of the Sodium Hydrogen Exchanger Protein in Plasmodium yoelii
Jamira Virk and Raghavendra Yadavalli
Since its discovery over 100 years ago, malaria has been the most important parasitic disease in the world. Malaria affects about 300 to 500 million people every year; killing 5 million people every year. The most virulent causative agent in humans is Plasmodium falciparum; it is an important member of the phylum Apicomplexa, which also includes Toxoplasma gondii. These organisms contain specialized, unique structures, including rhoptry organelles. In Plasmodium and Toxoplasma gondii, they assist invasion into the host cell. Analyses have been performed on proteins located in rhoptries in Toxoplasma and Plasmodium. Among the proteins that have been analyzed, the sodium hydrogen exchanger protein has been found in these parasites, but not much is known about its characterization and function in Plasmodium. This protein was found to be localized in the rhoptries in Toxoplasma gondii in an experiment performed by Karasov et. al. The protein homologue in T. gondii, TgNHE2, has become the first intracellular sodium hydrogen exchanger (NHE) characterized in a protozoan parasite. Proteome analysis show that there are four NHE2 in T. gondii, but only two are known in the parasite. Comparative analyses including protein sequence alignments were performed showing the relationship of this protein across several species. This protein is found across several species of Apicomplexa and vary widely in size and weight. The four proteins that were analyzed were two strains in P. falciparum (PFIT_1302700 and PF3D7_1303500), P. yoelii (PY02931), and T. gondii (TGME49_105180). The analysis shows regions of similarity in the location of the transmembrane domains amongst PFIT, PF3D7, and PY02931. These species also contain regions of asparagine-, aspartic acid-, and lysine-rich regions that overlap. This protein is also present in mammals, in the mitochondria. It is primarily characterized as an intracellular protein in mammals although it is found in the plasma membrane of certain cells. The characterization of this protein in T. gondii will provide a groundwork in better understanding its function in Plasmodium, specifically P. falciparum.
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GPU Assisted High Performance RSA Encryption
Zhe Zhao and Alec McGrady
GPU has become highly popular due to its parallel computing ability. It accelerates operations in large scale. Many applications associate with intensive computations. RSA cryptosystem is one of them that can benefit from its utility. The purpose of this research is to implement RSA encryption and decryption by utilizing GPU to enhance the performance of the process. Since RSA public key and private key operations actually consist of large integer multiplications in a finite field, this research explores the efficient algorithms and implementations of the high performance GPU large integer multiplications. Our work has been implemented on the following three different GPU platforms: (1) Ohio Super Computing's Ruby machine; (2) NVidia Quadro K620 graphic card on HP Z230 workstation; (3) NVidia Shield 8” Tablet. In particular, we develop and implement the row-wise and column-wise multiplication schemes that sufficiently take the advantage of GPU computing parallelism. Our experiments show that the GPU- assisted large integer multiplication accelerates the process by up to 200 times. The performance enhancement of RSA operations is also observed on the platforms of Ohio Super Computing Center and HP workstation. Due to the time constraint, we only test the 1024-bit RSA operations. In our future work, we expect to have much more performance enhancement on the RSA cryptosystem operations with larger key sizes.
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