Investigating the use of in situ liquid cell scanning transmission electron microscopy to explore DNA-mediated gold nanoparticle growth

Engineering nanoparticles with desired shape-dependent properties is the key to many applications in nanotechnology. Although many synthetic procedures exist to produce anisotropic gold nanoparticles, the dynamics of growth are typically unknown or hypothetical. In the case of seed-mediated growth in the presence of DNA into anisotropic nanoparticles, it is not known exactly how DNA directs growth into specific morphologies. A series of preliminary experiments were carried out to contribute to the investigation of the possible mechanism of DNA-mediated growth of gold nanoprisms into gold nanostars using liquid cell scanning transmission electron microscopy (STEM). Imaging in the liquid phase was achieved through the use of a liquid cell platform and liquid cell holder that allow the sample to be contained within a chip sandwich between two electron transparent windows. Ex situ growth experiments were performed using Au-T30 NPrisms (30-base thymine oligonucleotide-coated gold nanoprisms) that are expected to grow into gold nanostars. Growth to form these nanostars were imaged using TEM (transmission electron microscopy) and liquid cell STEM (scanning transmission electron microscopy). An attempt to perform in situ growth experiments with the same Au-T30 nanoprisms revealed challenges in obtaining desired morphology results due to the environmental differences within the liquid cell compared to the ex situ environment. Different parameters in the experimental method were explored including fluid line set up, simultaneous and alternating reagent addition, and the effect of different liquid cell volumes to ensure adequate flow of reagents into the liquid cell. Lastly, the binding affinities were compared for T30 and A30 DNA incubated with gold nanoparticles using zeta potential measurements, absorption spectroscopy, and isothermal titration calorimetry (ITC). It was previously reported thymine bases have a lower binding affinity to gold surfaces than adenine bases. However, the results reported here contradict the previously reported data. Future prospectives on this work are outlined

Consumer perceptions of the internet as a product and service infomation source

The Internet is fast becoming an important product and service information source. Consumers are using the medium for gathering information on products and services. The Internet has unique characteristics, which makes it a powerful medium for communication. However, what is the perception of the product and service information on the Internet? This study aims to contribute to an understanding of consumers\u27 perception of product and service information on the Internet. The research is exploratory in nature. Consumers\u27 perceptions towards the Internet as a product and service information source were measured along a construct relating to perceptions towards the Internet information. A self-administered questionnaire was employed to capture the perceptions of 300 participants. Descriptive statistics and multivariate techniques, including Factor Analysis, Discriminant Analysis and Cluster Analysis, were used in the data analysis. The study found interesting differences in the perceptions held by participants on the product and service information on the Internet. The findings suggest that participants have highly positive perceptions on the wide coverage, currency, relevancy, and depth of product and service information on the Internet. They also have moderately positive perceptions on the credentials of the information providers as being knowledgeable, qualified and experts. However, on the most important evaluative criteria of trustworthiness (fairness, honesty and unbiasness) of the information on the Internet, participants have weak and less positive perceptions. Factor Analysis revealed that there are three important dimensions in the perception of information on the Internet -quality, authority and scope. Cluster Analysis and Discriminant Analysis was then conducted to explore the similarity and differences between groups on those three dimensions. The Cluster Analysis revealed that there are four distinct clusters - Highly Specific Information Seekers, Disillusioned Information Seekers, Undirected Information Seekers and Intuitive Information Seekers. The Discriminant Analysis revealed that the variables in the study (i.e. gender, level of Internet experience, age and income) are not powerful predictors of the participants\u27 perceptions of the product and service information on the Internet. The implications of the findings for marketers are discussed

A Music Composition Through the Use of Animal Sounds

The knowledge on animals has been studied over many years by researching and understanding animal behavior and creativity with music. Bioacoustics shows a great deal when it comes to collecting sounds through many principles for sound data collection. With saved recording of animals, music, speeches, and so much more, it has impacted the way music is created through technology. Music production has been advancing in many creative ways. The foundation of sound manipulation is musique concrète. The project uses these concepts of audio recording and digital sounds to produce a composition that includes animal sounds

Traumas New and Old: A Two Paper Exploration of Co-Parenting Relationships and Heightened Racial Tension for Black, Latinx, and Asian Parents During the COVID-19 Pandemic

The COVID-19 pandemic broadly impacted the human experience since it emerged on the scene in late 2019/early 2020 (Centers for Disease Control & Prevention (CDC) 2020). Parents in the United States experienced a uniquely high level of stress related to childrearing through the pandemic and the social-political implications of pandemic-related societal decision making (Elder & Greene, 2021; Fortuna et al., 2020; Patrick et al., 2020). People of color experienced compounding stressors of the heightened racial tensions, which reached a boiling point with the murder of George Floyd on May 25, 2020, on top of decades of inequities embedded within social systems (Buchanan et al., 2020; DePouw, 2017). This two-paper qualitative dissertation study interviewed fifteen parents of color with school-aged children who are in coparenting relationships to explore two independent but related experiences of pressures faced by parents of color during the COVID-19 pandemic and temporally associated heightened racial tensions. The first paper explores stressors on parents of color related to COVID-19 (e.g., remote learning, access to services, household management, changes extended social support, etc.) and the changes in and impact on coparenting relationships, with a focus on how coparenting relationships worked to buffer and/or aggravate parental stress levels. The second paper explores how parents of color experienced, coped with, and navigated parenting during the rise in societal racial stress in late 2019/early 2020 through fall of 2022 that spurred the uptick in the Black Lives Matter movement and the beginning of the Stop Asian Hate movement. A total of 15 parents of color participated in qualitative interviews. All data were analyzed using thematic analysis. Analyses revealed several salient themes that centered around coparenting, social support, and that illuminated the unique stressors experienced by parents of color. Implications for social work practice, policy, and research are discussed

Using Architectural Constraints and Game Theory to Regulate International Cyberspace Behavior

The debate over whether cyberspace can or should be regulated is essentially dead. This is the conclusion being taught in law schools today. The battle between Judge Frank Easterbrook and Professor Lawrence Lessig over laws and horses , infamous among cyberspace legal scholars, became irrelevant when geographically-based governments began regulating Internet related activities. However, debate over how the Internet should be regulated continues. One way of framing this debate is in terms of deciding how to regulate behavior in cyberspace. Professor Lessig postulated four kinds of constraints regulate behavior: (1) social norms, (2) markets, (3) law, and (4) architecture. This comment first argues that lawmakers must focus on using the fourth constraint-architecture-if an interconnected global, democratic society is truly an international goal. Second, this comment argues that, in focusing on architectural constraint, game theory is a uniquely appropriate tool for analyzing Internet issues and developing Internet laws

Data base for crack growth properties of materials

A computerized data base of crack growth properties of materials was developed for use in fracture control analysis of rocket engine components and other NASA space hardware. The software system has files of basic crack growth rate data, other fracture mechanics material properties such as fracture toughness and environmental crack growth threshold values, and plotting and fitting routines for deriving material properties for use in fracture control analysis. An extensive amount of data was collected and entered, and work is continuing on compiling additional data. The data base and software codes are useful both for fracture control analysis and for evaluation or development of improved crack growth theories

Remote Sensing of Green Leaf Area Index in Maize and Soybean: From Close-Range to Satellite

This dissertation seeks to explore alternative methodologies for estimating green leaf area index (LAI) and crop developmental stages. Specifically this research [1] developed an approach for creating a Moderate Resolution Imaging Spectroradiometer (MODIS) high spatial resolution product for estimating green LAI on the base of data collected using two different close-range sensors. It was determined that the vegetation indices (VIs) Wide Dynamic Range Vegetation Index (WDRVI) and Enhanced Vegetation Index 2 (EVI2) were capable of accurate estimation of green LAI from MODIS 250 m data using models developed from hyperspectral (RMSE \u3c 0.69 m2 m-2; CV \u3c 33%) or multispectral sensors (RMSE \u3c 0.69 m2 m-2; CV \u3c 34%). [2] Explored a new approach for maximizing the sensitivity of VIs to green LAI. Rather than use one VI, we suggested using multiple VIs in different LAI dynamic ranges. Thus, the sensitivity of the VI to the green LAI was preserved and simpler linear models could be used instead of complex non-linear ones. Two combined vegetation indices (CVI) were presented using near infrared and either the red or red edge bands and were accurate in estimating green LAI. While the red band is more common in satellite sensors, the indices use red edge band were found to be species independent for maize and soybean. The two species-independent VIs used in the CVI were Red Edge Normalized Difference Index (Red Edge NDVI) and Red Edge Chlorophyll Index (CIred edge). [3] Algorithms were developed for estimating green LAI in four vastly different crops (maize, potato, soybean, and wheat) that do not require re-parameterization. The most promising VIs for developing a unified algorithm utilized either a green or red edge bands. [4] It was found that, in addition to traditionally used (VIs), the 2-dimensional spectral spaces (e.g. red vs. green reflectance) were capable of identifying four distinct stages of crop development (e.g. soil/residue, green-up, vegetative, and senescence). Advisor: Anatoly A. Gitelso

Online Primal-Dual Algorithms with Configuration Linear Programs

In this paper, we present primal-dual algorithms for online problems with non-convex objectives. Problems with convex objectives have been extensively studied in recent years where the analyses rely crucially on the convexity and the Fenchel duality. However, problems with non-convex objectives resist against current approaches and non-convexity represents a strong barrier in optimization in general and in the design of online algorithms in particular. In our approach, we consider configuration linear programs with the multilinear extension of the objectives. We follow the multiplicative weight update framework in which a novel point is that the primal update is defined based on the gradient of the multilinear extension. We introduce new notions, namely (local) smoothness, in order to characterize the competitive ratios of our algorithms. The approach leads to competitive algorithms for several problems with convex/non-convex objectives