Matching Items (6)
Filtering by
- All Subjects: DNA nanotechnology
- All Subjects: Motivation
- Creators: Gould, Ian
- Resource Type: Text
Description
DNA is a unique, highly programmable and addressable biomolecule. Due to its reliable and predictable base recognition behavior, uniform structural properties, and extraordinary stability, DNA molecules are desirable substrates for biological computation and nanotechnology. The field of DNA computation has gained considerable attention due to the possibility of exploiting the massive parallelism that is inherent in natural systems to solve computational problems. This dissertation focuses on building novel types of computational DNA systems based on both DNA reaction networks and DNA nanotechnology. A series of related research projects are presented here. First, a novel, three-input majority logic gate based on DNA strand displacement reactions was constructed. Here, the three inputs in the majority gate have equal priority, and the output will be true if any two of the inputs are true. We subsequently designed and realized a complex, 5-input majority logic gate. By controlling two of the five inputs, the complex gate is capable of realizing every combination of OR and AND gates of the other 3 inputs. Next, we constructed a half adder, which is a basic arithmetic unit, from DNA strand operated XOR and AND gates. The aim of these two projects was to develop novel types of DNA logic gates to enrich the DNA computation toolbox, and to examine plausible ways to implement large scale DNA logic circuits. The third project utilized a two dimensional DNA origami frame shaped structure with a hollow interior where DNA hybridization seeds were selectively positioned to control the assembly of small DNA tile building blocks. The small DNA tiles were directed to fill the hollow interior of the DNA origami frame, guided through sticky end interactions at prescribed positions. This research shed light on the fundamental behavior of DNA based self-assembling systems, and provided the information necessary to build programmed nanodisplays based on the self-assembly of DNA.
ContributorsLi, Wei (Author) / Yan, Hao (Thesis advisor) / Liu, Yan (Thesis advisor) / Chen, Julian (Committee member) / Gould, Ian (Committee member) / Arizona State University (Publisher)
Created2014
Description
Understanding the relationships between chemistry students' motivation, performance, and gender can help identify and inform ways in which chemistry education might be improved. Students from four CHM 101 classes with two different instructors were surveyed using an adapted Science Motivation Questionnaire II, and motivation data was analyzed with respect to final course performance. Gender data was available for two of these classes, and motivation results analyzed by gender for these classes. Exam scores and gender data was obtained from one of the instructors for CHM 101 courses taught over the past five years and were also analyzed. The motivational study involved small sample sizes, especially in the motivation by gender study. Career motivation, grade motivation, self-efficacy, and total motivation declined over the course of the semester in the four classes combined. Self-efficacy and career motivation were found to predict final course performance only at the end of the semester. Self-efficacy strongly predicted performance, and career motivation was negatively correlated with performance. Female students had higher grade motivation at the end of the semester and lost more self-efficacy over the course of the semester than male students. Gender-performance analysis showed that male students scored slightly higher on exams on average, but that female students received a higher percentage of "A"s and a lower percentage of "D"s, "E"s, and "W"s in the majority of the semesters.
ContributorsJohnson, Walter Gregory (Author) / Gould, Ian (Thesis director) / Wolf, George (Committee member) / Austin, Ara (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Life Sciences (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)
Created2015-05
Description
The goal of this investigation was to perform a correlational analysis of the intelligence mindsets, motivational background, and significance of gender identity as factors driving student success. 42 students enrolled in Computer Science and Engineering (CSE) 110: Principles of Programming with Java completed a modified Scientific Measurement Questionnaire (SMQ), a survey instrument designed to study the previously mentioned factors. This survey was modeled on a similar survey administered by Dr. Ian Gould to students enrolled in his Organic Chemistry course at Arizona State University. Following the development of a scoring system to generate quantifiable data, it was determined that students in this course displayed a greater inclination towards beliefs in malleable intelligence and in an intrinsic locus of control as opposed to a belief in static intelligence and an external locus of control. Students exhibited a multi-faceted approach in responding to the questions in the motivational background section, indicating that there were no distinctively dominating factors driving student motivation. Instead, it was observed that students generally derived motivation from these factors in a synergistic fashion. Responses to questions regarding gender indicated that while students believed that the way they were perceived by others was significantly influenced by their gender, the notion of gender identity played little to no role in their overall personal identity and self-schema. As the study was designed to offer insight into the role of gender identity and the population discrepancies within the course, it is important to note that the findings suggest gender identity is not a primary factor of concern with regard to student performance. While the data acquired suggested potential trends in student mindsets, a notable limitation of the scope of the project was the undersized sample population.
ContributorsLevinthal, Ryan (Co-author) / Santos, Cedric (Co-author) / Gould, Ian (Thesis director) / Redding, Kevin (Committee member) / School of Molecular Sciences (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Due to its difficult nature, organic chemistry is receiving much research attention across the nation to develop more efficient and effective means to teach it. As part of that, Dr. Ian Gould at ASU is developing an online organic chemistry educational website that provides help to students, adapts to their responses, and collects data about their performance. This thesis creative project addresses the design and implementation of an input parser for organic chemistry reagent questions, to appear on his website. After students used the form to submit questions throughout the Spring 2013 semester in Dr. Gould's organic chemistry class, the data gathered from their usage was analyzed, and feedback was collected. The feedback obtained from students was positive, and suggested that the input parser accomplished the educational goals that it sought to meet.
ContributorsBeerman, Eric Christopher (Author) / Gould, Ian (Thesis director) / Wilkerson, Kelly (Committee member) / Mosca, Vince (Committee member) / Barrett, The Honors College (Contributor) / Computer Science and Engineering Program (Contributor)
Created2013-05
Description
Since the conception of DNA nanotechnology, the field has evolved towards the development of complex, dynamic 3D structures. The predictability of Watson-Crick base pairing makes DNA an unparalleled building block, and enables exceptional programmability in nanostructure shape and size. The work presented in this dissertation focuses on expanding two facets of the field: (1) introducing functionality through the incorporation of peptides to create DNA-peptide hybrid materials, and (2) the development of self-assembling DNA crystal lattices for scaffolding biomolecules. DNA nanostructures have long been proposed as drug delivery vehicles; however, they are not biocompatible because of their low stability in low salt environments and entrapment within the endosome. To address these issues, a functionalized peptide coating was designed to act as a counterion to a six-helix bundle, while simultaneously displaying numerous copies of an endosomal escape peptide to enable cytosolic delivery. This functionalized peptide coating creates a DNA-peptide hybrid material, but does not allow specific positioning or orientation of the peptides. The ability to control those aspects required the synthesis of DNA-peptide or DNA-peptide-DNA conjugates that can be incorporated into the nanostructure. The approach was utilized to produce a synbody where three peptides that bind transferrin with micromolar affinity, which were presented for multivalent binding to optimize affinity. Additionally, two DNA handle was attached to an enzymatically cleavable peptide to link two unique nanostructures. The second DNA handle was also used to constrain the peptide in a cyclic fashion to mimic the cell-adhesive conformations of RGD and PHSRN in fibronectin.
The original goal of DNA nanotechnology was to use a crystalline lattice made of DNA to host proteins for their structural determination using X-ray crystallography. The work presented here takes significant steps towards achieving this goal, including elucidating design rules to control cavity size within the scaffold for accommodating guest molecules of unique sizes, approaches to improve the atomic detail of the scaffold, and strategies to modulate the symmetry of each unique lattice. Finally, this work surveys methodologies towards the incorporation of several guest molecules, with promising preliminary results that constitute a significant advancement towards the ultimate goal of the field.
ContributorsMacCulloch, Tara Lynn (Author) / Stephanopoulos, Nicholas (Thesis advisor) / Borges, Chad (Committee member) / Gould, Ian (Committee member) / Arizona State University (Publisher)
Created2021
Description
Deoxyribonucleic acid (DNA), a biopolymer well known for its role in preserving genetic information in biology, is now drawing great deal of interest from material scientists. Ease of synthesis, predictable molecular recognition via Watson-Crick base pairing, vast numbers of available chemical modifications, and intrinsic nanoscale size makes DNA a suitable material for the construction of a plethora of nanostructures that can be used as scaffold to organize functional molecules with nanometer precision. This dissertation focuses on DNA-directed organization of metallic nanoparticles into well-defined, discrete structures and using them to study photonic interaction between fluorophore and metal particle. Presented here are a series of studies toward this goal. First, a novel and robust strategy of DNA functionalized silver nanoparticles (AgNPs) was developed and DNA functionalized AgNPs were employed for the organization of discrete well-defined dimeric and trimeric structures using a DNA triangular origami scaffold. Assembly of 1:1 silver nanoparticle and gold nanoparticle heterodimer has also been demonstrated using the same approach. Next, the triangular origami structures were used to co-assemble gold nanoparticles (AuNPs) and fluorophores to study the distance dependent and nanogap dependencies of the photonic interactions between them. These interactions were found to be consistent with the full electrodynamic simulations. Further, a gold nanorod (AuNR), an anisotropic nanoparticle was assembled into well-defined dimeric structures with predefined inter-rod angles. These dimeric structures exhibited unique optical properties compared to single AuNR that was consistent with the theoretical calculations. Fabrication of otherwise difficult to achieve 1:1 AuNP- AuNR hetero dimer, where the AuNP can be selectively placed at the end-on or side-on positions of anisotropic AuNR has also been shown. Finally, a click chemistry based approach was developed to organize sugar modified DNA on a particular arm of a DNA origami triangle and used them for site-selective immobilization of small AgNPs.
ContributorsPal, Suchetan (Author) / Liu, Yan (Thesis advisor) / Yan, Hao (Thesis advisor) / Lindsay, Stuart (Committee member) / Gould, Ian (Committee member) / Arizona State University (Publisher)
Created2012