UMBC Theses and Dissertations

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International Adoption Trends From South Korea to America from the 1990s to 2000s
(2024-01-01) Beyer, Emily; Oyen, Meredith; History; Historical Studies
Leading up to 1988 Seoul Summer Olympics, Western media revealed just how many Korean children were sent overseas, along with the price point of these children. There has been intensive research that has been done covering these initial adoptees, specifically those adopted from the 1960s-1980s. And, they show that this initial wave of adoption was fueled by the concept of “Christian Americanism.” Although the more recent studies show remnants of these reasons for adoption from Korea, there is many more factors at work. Korean adoption never fully dissolved. International adoption from Korea is still ongoing, but the adoptees, themselves, are often left out of this narrative. They are pushed to the background of this adoption narrative leaving out a vital source of information. With the help of scholars works, adoptee interviews, and academic journals, the purpose of this study was to find a reason for the Korean adoptions heading into the 21st century.
FINITE ELEMENT ANALYSIS OF A THREE-STAGE 3D PRINTED TENSEGRITY ICOSAHEDRON STRUCTURE
(2024-01-01) Bharata, Abhinav; Zhu, Weidong; Mechanical Engineering; Engineering, Mechanical
Tensegrity is a crucial factor in the progress of humanity in various domains, including architecture and biology. This work is centered on the tensegrity structure of an icosahedron configuration, which is also referred to as a diamond tensegrity. This structure consists of six bars in each stage, with four strings linked to each end of the bar, forming a diamond shape. A three-stage tensegrity-icosahedron (T-Icosahedron) structure, composed of 3D printed components, was studied. The entire structure contains a total of 72 strings and 18 bars manufactured from Ninja Flex and Polylactic acid material. A novel vibration-based method was developed to measure tensions in the strings in the structure. A Polytec laser vibrometer was utilized to accurately measure the tensions and calibrate the nodal coordinates of the structure. The study subsequently focuses on a finite element analysis technique to examine the natural frequencies of the structure and generate its mode shapes using MATLAB. The obtained results are then compared with those obtained from the commercial finite element program ANSYS. This work provides a thorough examination of the T-Icosahedron structure, as well as potential opportunities for additional investigation involving alterations in geometry and material composition of the structure.
Quantitation of Per- and Polyfluoroalkyl Substances (PFAS) in Aquaculture Systems
(2024-01-01) Belunis, Amanda; LaCourse, William R; Chemistry & Biochemistry; Chemistry
Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been used since the 1940s in a wide variety of applications including water-repellant clothing, stain-resistant sprays, food packaging, and aqueous film forming foam (AFFF). Due to their prevalent use in consumer products, and their persistence in the environment, PFAS have leached into the air, soil, and water, leaving almost no ecosystem untouched. PFAS are known to be bioaccumulative and studies have shown potential links between exposure and several negative human health effects. A large focus has been placed on understanding and regulating PFAS exposure. Contaminated food and water are believed to be the main routes of exposure for the general population. It has been hypothesized that fish and seafood are one of the main dietary sources of exposure, as associations between consumption and PFAS serum concentrations have been observed globally. With efforts to improve environmental conservation and sustainability while keeping up with increasing demands for fish and seafood, aquaculture has grown rapidly since the 1980s. While numerous studies have shown the presence of PFAS in various environments, data regarding the compounds in aquaculture environments is scarce. In recent years, a large focus has been to reduce the potential for environmental interactions with coastal aquaculture facilities, leading to the increase in land-based marine and freshwater systems. There is currently a lack of understanding with regards to the presence of PFAS in aquaculture environments. As farmed fish continues to account for a large portion of fish for consumption, it is important to understand the fate and transport of PFAS in these environments, requiring proper analytical techniques to be developed. A liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the separation and detection of 40 target PFAS. Various solid phase extraction (SPE) cartridges were selected and tested to determine the best extraction technique for the target analytes. Automated and manual SPE setups were compared, and the automated setup shows a statistically significant increase in average recovery and reproducibility. Instrument and method figures of merit show the sensitivity, reproducibility, and robustness of the developed method. The method was applied to a proof-of-concept study testing various types of aquaculture tanks across two facilities and PFAS were found in each of the samples tested.
Hybrid Gold Nanostructures with Unique Architectures: From Potential Applications in Drug Delivery to Photonic Devices
(2024-01-01) Baradaran Kayyal, Tohid; Daniel, Marie-Christine; Chemistry & Biochemistry; Chemistry
The domain of nanotechnology has experienced remarkable progress through the engineering of hybrid nanostructures. These structures integrate diverse materials to create synergistic properties that are unachievable or less efficient when using individual components alone. Central to this progress are gold-based hybrid nanostructures, favored for their inherent advantages ranging from structural diversity and biocompatibility to remarkable optical properties. The present study focuses on the creation of gold-based hybrid systems with special nanostructures (rattle and bipyramid shapes), which have potential for medical and optical applications. The first project focuses on the design of a porous gold nanoarchitecture, termed nanorattles. These structures consist of a porous gold cage surrounding a core, offering two accessible surfaces within a single system. This design can enhance the surface area available for cargo loading, which is advantageous for drug delivery applications. Incorporated within these nanorattles are dendrons—highly branched nanopolymers—that play a crucial role in forming a hybrid structure. Dendrons not only act as catalysts, facilitating the formation of the porous cage and the overall nanorattle structure, but also serve as a nanosystem capable of covalently carrying cargo. Cisplatin, a widely used anticancer drug, is employed as a model cargo to demonstrate the potential of gold nanorattles in targeted drug delivery applications. The other project explores the directed assemblies of gold nanoparticles and quantum dots (QDs) to form a novel hybrid nanostructure yielding unique optical characteristics through plasmon-exciton coupling. The gold used in this assembly is in the form of bipyramids, chosen for their distinctive asymmetrical shape and sharp end tips. The sharp end tips of the gold nano bipyramids (AuBPs) are the designated locations for placing the QDs. Upon light irradiation, the excitons from the QDs couple with the plasmons resonating from the ends of the AuBPs, facilitating efficient plasmon-exciton coupling. The resulting coupling occurs through a selective copper-free click reaction between surface modified QDs and AuBPs. The significance of this plasmon-exciton coupling extends particularly to photonic devices, where it can greatly enhance device performance and efficiency in light manipulation, driving next-generation photonic technologies. The PhD dissertation comprehensively explains the foundational concepts, intrinsic properties, and importance of hybrid nanomaterials as outlined in the literature review. It details the experimental procedures for synthesizing the aforementioned gold nanostructures, presents characterizations and analyses to validate their structure, size, and properties, and discusses the results, interprets data, and explores potential applications.
Immigrant families' risk and resilience: A multi-method investigation of cultural caregiving and socialization within racialized contexts
(2024-01-01) Aquino, Ana Katrina; Cheah, Charissa S. L.; Psychology; Psychology
Latino and Asian American children and youth make up an increasing proportion of the United States population, yet they remain vulnerable to marginalization in racialized contexts. These contexts include heightened anti-Latino sentiment fueled by anti-immigrant rhetoric and a surge in anti-Asian hate during the COVID-19 pandemic. These challenges, compounded by the need to navigate both their heritage and mainstream cultures, make the role of immigrant caregivers critical in fostering resilience and well-being among children and youth. Guided by several models centering the unique experiences of racially and ethnically minoritized immigrant families, this dissertation comprising three studies investigated how immigrant caregivers and parents employ culturally informed practices to buffer the effects of racial discrimination. Using both qualitative and quantitative methods, this dissertation underscores how caregiving practices serve as adaptive strategies to combat racial marginalization and support children’s well-being.The first study examined the motivations, needs, and experiences of 41 Latino immigrant Family, Friend, and Neighbor child care providers. Findings from focus groups revealed that these caregivers, guided by cultural values like familismo (family unity and commitment), sought to provide safe and nurturing environments for children and meet their emotional needs. Despite facing barriers, they leveraged community networks and intrinsic motivation to fulfill these roles. The second study explored how experiences of racial discrimination experiences among 128 Chinese American parents were related to their adolescents’ well-being during the COVID-19 pandemic. In the face of discrimination, parents communicated messages to increase their children’s awareness of discrimination, but the impact of these messages depended on parental racial socialization competency. Specifically, parents’ higher confidence, knowledge, and skills in racial discussions mitigated the negative effects of awareness of discrimination messages on adolescents’ well-being. The third study used mixed methods with 65 Filipino American parents of adolescents to examine how parents' critical consciousness is related to their racial-ethnic socialization messages. Quantitative findings linked parents' critical consciousness to experiences of discrimination and several racial-ethnic socialization messages, while qualitative findings highlighted key themes in parents’ racial discussions. Converging results showed distinct messaging patterns based on parents’ critical consciousness level, though all parents emphasized belonging and connectedness, reflecting the Filipino value of kapwa (shared identity). Together, the findings from these three studies emphasize the adaptability of immigrant caregiving practices within racialized U.S. contexts and contribute to theories of immigrant risk and resilience. This dissertation also highlights the importance of culturally responsive support systems and socialization practices in fostering resilience among immigrant children and adolescents.
Development of a Novel General-purpose Three-dimensional Continuously Scanning Laser Doppler Vibrometer System
(2024-01-01) Yuan, Ke; Zhu, Weidong; Mechanical Engineering; Engineering, Mechanical
The objective of this work is to develop a novel general-purpose three-dimensional (3D) continuously scanning laser Doppler vibrometer (CSLDV) system for 3D vibration measurement of structures with arbitrarily curved surfaces. This work is motivated by the fact that 3D full-field vibration measurement is significant to structures, especially those with curved and complex surfaces such as turbine blades, vehicle bodies, and aircraft wings. Modal tests that obtain vibration components along three axes of a coordinate system can provide more information and locate defects on more complex structures than those that only obtain single-axis vibration, and can improve the accuracy of their structural health monitoring. 3D full-field vibration can also be used to identify dynamic characteristics of a complex structure and update its finite element model during structural analysis and product design where vibration must be determined in all its components. A triaxial accelerometer can be attached on a structure to measure its 3D vibrations, which can lead to mass loading, especially when multiple triaxial accelerometers are needed in modal tests of light-weight structures. A 3D scanning laser Doppler vibrometer (SLDV) system can be used to measure 3D vibration of a structure in a non-contact. However, it usually takes the 3D SLDV system a long time to obtain high spatial resolution, especially for structures with large surfaces, because laser spots must stay at one measurement point for enough time before they are moved to the next one to conduct more averages of measurement data when high frequency resolution is needed. The 3D CSLDV system proposed in this work can rapidly obtain 3D full-field vibration shapes, such as mode shapes and operating deflection shapes (ODSs) of a structure, in a non-contact way by sweeping three laser spots over its surface in a continuous and synchronous mode. The universality of the system lies in its capability to measure vibration of structures with various shapes, including flat, curved, and difficult-to-access areas, as well as structures under various excitation, including sinusoidal and random excitation. The major contributions of this work include: 1) developing a calibration method to achieve synchronous scanning of three laser spots, and improving it to fit measurement on curved surfaces and virtual surfaces behind a mirror; and 2) developing a signal processing method to identify modal parameters of structures under random excitation.
A Qualitative Exploration of the Acculturative Process of Resettled Rohingya Refugees in the United States
(2024-01-01) Zhao, Jenny; Brodsky, Anne E; Psychology; Psychology
This phenomenological study explored the complex, multi-directional acculturationprocess of resettled Rohingya refugees in the United States. By taking a phenomenological approach, the study aimed to expand the traditional parameters of acculturation research, exploring acculturation beyond mere social integration, and humanizing the acculturative experience. This study employed semi-structured interviews, facilitated in English, with eight resettled Rohingya refugees living in the United States. The interviews were transcribed, coded, and qualitatively analyzed to describe the phenomenon of the unique acculturative process as experienced from the Rohingya migration context. All participants were active in the Rohingya community as cultural brokers, interpreters, or community-based leaders. While all eight of the participants had unique experiences, five general themes emerged. Three themes captured the effects of prolonged exposure to institutionalized discrimination on resilience, acculturative experiences, and shifts in Rohingya identity, goals, and values. Two themes reflected the process of liberation to pursue wellness in the post-resettlement context. The findings demonstrate how Rohingya diaspora communities are overcoming oppressive conditions and defining liberation by creating cultural roots and establishing permanency.
ENABLING DATA PRIVACY THROUGH ANONYMIZATION IN CENTRALIZED AND DISTRIBUTED ENVIRONMENTS TO SECURELY SHARE NETWORK TRACE & HEALTHCARE DATA
(2024-01-01) Xenakis, Antonios; Karabatis, George; Chen, Zhiyuan; Information Systems; Information Systems
Privacy is the right to control sensitive information and protect it from unauthorized access or disclosure. Anonymization ensures privacy by removing or altering sensitive data, making it difficult to uncover the original information. This dissertation investigates anonymization techniques in both centralized and distributed environments and emphasizes on preserving the privacy of data in two different application domains, namely network trace data, and healthcare data. Organizations collect vast amounts of network trace data for purposes such as network optimization and user behavior analysis but are often hesitant to share this data due to privacy concerns and proprietary information. Existing anonymization tools have significant shortcomings: they lack provable protection and rely heavily on parameter settings without offering adequate guidance. This dissertation proposes a self-adaptive and secure approach for sharing network trace data in order to maintain privacy by removing or obfuscating sensitive information. Additionally, we investigate network trace data anonymization in distributed environments. Organizations often rely on integrating data from multiple sites, presenting challenges in anonymization due to the required communication. This dissertation introduces two new methods for cluster-based distributed anonymization: one based on distributed coordinated anonymization and the other on top-down distributed anonymization. These methods enable each site to anonymize its data in a coordinated manner, allowing the merged anonymized data to be centrally analyzed. Finally, this dissertation examines anonymization and integration of healthcare data. Anonymizing healthcare data is essential for protecting privacy, requiring the removal of personal identifiers while ensuring accurate integration and alignment of distributed patient information. In order to address the anonymization and integration challenge of distributed healthcare data, we introduce a novel approach to anonymize distributed data with limited communication, followed by an integration process for subsequent analysis. This approach ensures consistency across sources so that anonymized data can be directly integrated without expensive procedures. A hash-function generator is used to create consistent noise based on a locally generated seed, which also serves as a unique identifier for data integration. Our approaches overcome these limitations by providing provable protection and automatically optimizing parameter settings. The proposed solutions support differential privacy, k-anonymity and random response. Experimental evaluations demonstrate that the proposed techniques ensure privacy through anonymization, maintain data utility, and enable efficient integration of distributed anonymized data with minimal computational overhead.
Art-Style is the Future: The Spider-Verse as a Model for Conceptualizing and Visualizing Graphic Narratives in Visual Media
(2024-01-01) Wildy, Caron; Saper, Craig; Pasandi, Haniyeh B.; Language, Literacy & Culture; Language Literacy and Culture
Spider-Man: Into the Spider-Verse was a watershed moment in American animation. A stylized animated adaptation of Marvel Comics’ Spider-Man comics that drew directly on the aesthetics and visual language of comics, Into the Spider-Verse signaled a stylistic shift toward stylized aesthetics and imagery that aligned narrative and visuals and diverged from photorealistic aesthetics by drawing from diverse visual languages and aesthetics. The influence of Into the Spider-Verse, and its 2023 sequel Across the Spider-Verse, on the visual style of American animation serves as context for an exploration of how the films’ synthesis of aesthetics, visual languages and narratives from multiple visual mediums can inspire creators to reframe how they conceive of graphic narratives, visualize narrative, and adapt graphic narratives across visual mediums. The intersection between aesthetics and narrative in the Spider-Verse films challenges an emphasis on realism in the aesthetics of visual narratives in mainstream American visual narrative media that flatten visual signatures. The Spider-Verse films contest this emphasis on a mainstream stage and arrive in a landscape where audiences have greater access to a diverse visual storytelling aesthetics modes and mediums. This exploration uses analysis aesthetics and the synthesis of visual languages in the Spider-Verse films to demonstrate how the films offer a model for conceptualizing and visualizing narratives and explore how the convergence of aesthetics and visual language in the depiction of characters, environments, and scenes in the Spider-Verse films inspire creators to reframe the thinking that informs the conceptualizing, writing, and visualizing stories for scripted media.
ZNF217 promotes ovarian cancer progression through cancer cell intrinsic and extrinsic mechanisms
(2024-01-01) Wardrup, Kathryn; Padmanabhan, Achuth; Biological Sciences; Biological Sciences
High-grade serous ovarian cancer (HGSOC) remains the most lethal gynecological malignancy in the United States. Due to the absence of a reliable early diagnostic biomarker and the vague presentation of early clinical symptoms, most women will receive a diagnosis in a metastatic stage of disease progression. At this point, the efficacy of extant therapeutic strategies drops significantly, resulting in disappointing 5-year survival outcomes of less than 30%. This unfortunate clinical reality highlights the urgent need to identify new drug targets and more effective therapeutic strategies to treat metastatic ovarian cancer. Achieving this goal has proved challenging, largely due to the knowledge gap in our understanding of factors that drive metastasis and drug resistance in ovarian cancer. For these reasons, my thesis project has focused on identifying factors that contribute to ovarian carcinogenesis with the goal of identifying new molecular targets for the development of more efficacious therapeutic strategies. One such emergent molecular target is the transcription factor, Zinc Finger Protein 217 (ZNF217). The genomic locus harboring ZNF217 (20q13.2) is frequently amplified in many human cancers, including ovarian cancer. Consistently, ZNF217 mRNA is elevated in ovarian tumors. Importantly, elevated ZNF217 mRNA levels were found to correlate with poor clinical outcome in ovarian cancer patients. Despite this compelling link, very little is known about the role of ZNF217 in ovarian cancer pathogenesis. To address this critical knowledge gap, my thesis project focused on understanding the role of ZNF217 in ovarian carcinogenesis. Using clinically relevant in vitro as well as in vivo models, I establish that ZNF217 functions as a potent oncogene that promotes cell proliferation, epithelial-to-mesenchymal transition (EMT), metastasis, and chemoresistance in ovarian cancer cells. I show that ZNF217’s ability to drive these oncogenic phenotypes is dependent upon its ability to bind DNA and alter the expression of its downstream target genes. Interestingly, I discovered that ZNF217 co-operates with estrogen to promote metastatic phenotypes in ovarian cancer cells. These data underscore the critical role elevated ZNF217 may play in estrogen receptor-positive ovarian cancers. In addition to this, I show that ZNF217 overexpression impacts the expression of various cytokines and chemokines that are known to facilitate an immune-suppressive tumor microenvironment. These data suggest that ZNF217 overexpression could potentially impact the ovarian tumor microenvironment and the response of ovarian cancer cells to immunotherapy. Finally, my work demonstrates that ZNF217 stability is influenced by glucose availability in the microenvironment. Glucose deprivation caused ZNF217 depletion in cells and this effect was phenocopied by small molecules that activate the AMP-activated protein kinase (AMPK), an enzyme that regulates cellular energy levels. These data suggest that the effect of glucose on ZNF217 is likely mediated via the AMPK pathway. Taken together, my work shows that ZNF217 impacts ovarian cancer progression through both cancer cell intrinsic as well as extrinsic mechanisms. By establishing ZNF217 as a critical factor driving ovarian cancer progression and metastasis and identifying potential pathways that regulate ZNF217 levels in ovarian cancer cells, this thesis has laid groundwork to investigate ZNF217’s utility as a therapeutic target in metastatic ovarian tumors.
Dissecting the relationship between inflammation and the development of preneoplastic lesions in a mouse model of Interleukin-1?-mediated prostatic inflammation
(2024-01-01) Voskanian, Alin; Bieberich, Charles C; Biological Sciences; Biological Sciences
Prostate cancer is the second most common cancer in the USA and the fourth most common worldwide. Understanding the molecular mechanisms underlying the onset of this disease could lead to the development of earlier detection methods and effective treatments. Two histologically defined lesions that are precursors to human prostate cancer have been identified. Prostatic Intraepithelial Neoplasia (PIN) manifests as an abnormal accumulation of epithelial cells, often with nuclear atypia and enlarged nucleoli, within preexisting benign prostatic acini or ducts. Proliferative Inflammatory Atrophy (PIA) is described as an inflamed prostate gland with atrophic cells and a high percentage of mitotic epithelial cells. Chronic prostatic inflammation is known to increase prostate cancer risk. To better understand the role of chronic inflammation in the natural history of prostate cancer, with a focus on the emergence of early lesions, I employed a mouse model to undertake detailed molecular and histopathological analyses of the changes that occur in prostate epithelial cells upon prolonged exposure to inflammatory insult. In chapter one I discuss the merits of existing mouse prostatic disease models and highlight the advantages of the Induced Mouse Prostate Inflammation-IL1-driven (IMPI 1) model to study inflammation. In this model, consistent long-term prostatic inflammation occurs upon administration of doxycycline. In chapter two, I report the results of experiments designed to determine the histopathological and transcriptomic consequences of prolonged chronic inflammation in IMPI-1 mice and highlight the discovery of a gene expression signature that mimics key molecular features of human PIA. To gain understanding of the cells involved in the development of PIA and PIN lesions, in Chapter three, I report the results of bioinformatic analyses to compare gene expression profiles from IMPI-1 mice with single-cell RNA sequencing profiles from two genetically engineered mouse prostate cancer models. My results indicate that epithelial cells in IMPI-1 prostates that have been exposed to a prolonged inflammatory environment are enriched for genes that are expressed by Myc-expressing luminal cells and reactive basal and luminal cells in two independent mouse prostate cancer models. Myc-expressing luminal cells and reactive basal and luminal cells have been previously reported to be present in the early stages of prostate cancer development in these models. These data demonstrate that chronic inflammation in the mouse prostate leads to cellular and molecular changes that recapitulate features observed in precursor states of prostate cancer. This data provide strong experimental evidence in support of the longstanding hypothesis that chronic inflammation plays a causal role in the development of human prostate cancer. Future experiments will be required to identify other molecular and cellular alterations that permit precursor lesions to progress to overt adenocarcinoma
Broadband Energy Harvester for Tram Vibration Utilizing a 2-DOF Mass-Spring-Damper System
(2024-01-01) Umar, Hamza; Lee, Soobum; Mechanical Engineering; Engineering, Mechanical
This thesis presents a broadband vibrational energy harvesting device that utilizes a varied frequency from a tram using a 2-degree-of-freedom vibrational system combined with electromagnetic energy conversion. This paper will compare the power output for two design configurations of 2-DOF systems: open-end and closed-end designs. A stepwise optimization process is applied to determine (1) mechanical parameters for frequency tuning to adjust to the trams’ operational conditions, and (2) electromagnetic parameters for the whole system design to maximize power output. The 1st step will determine mechanical design parameters for frequency tuning: masses (mi) and spring constants (ki). The 2nd step will use these parameters as initial guesses and present electrical parameters and damping coefficients (ci) to maximize the power output in the frequency band of interest. The design results indicate that the closed-end design has a preferable performance, compared to the open-end design, in terms of broadband vibration energy harvesting with higher average power as well as manufacturability within design constraints.
The Association of Negative Emotions and Stress with Undiagnosed Diabetes in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)
(2024-01-01) Splain, Ashley Marie; Khambaty, Tasneem; Psychology; Psychology
Psychological factors play in critical role in disease management, yet most research has focused on sociodemographic factors related to undiagnosed diabetes. Consequently, this study examined associations between psychological factors and diabetes diagnosis status among participants of the Hispanic Community Health Study/Study of Latinos. Participants were 1,012 Hispanic/Latino adults (mean (SD) age: 54 (13) years) with T2DM. Individuals self-reporting T2DM or on medication were categorized as diagnosed (68%; N = 669). Three SEM models were examined, 1) trait emotions: anxiety, loneliness, and hopelessness, 2) distinct stressors: lifetime stress and chronic stress, 3) state emotions: depression and perceived stress. Only distinct stressors appeared significant, more chronic stressors (? = .68, p < .001) and fewer lifetime stressors (? = -.56, p = .001) were associated with diagnosed vs. undiagnosed diabetes. Findings suggest that distinct stressors rather than emotional distress may be of greater relevance to diabetes diagnosis status among Hispanics/Latino adults.
NANOFABRICATION AND TESTING OF PHOTONICS AND ELECTRONICS DEVICES
(2024-01-01) Sood, Rachit Mohan; Choa, Fow-Sen; Computer Science and Electrical Engineering; Engineering, Computer
Nanotechnology, with its ability to manipulate matter at the smallest scales has become the cornerstone of modern optoelectronics. One nanometer is equivalent to one billionth or 10-9 of a meter. To put the scale into perspective, the size of a nanometer compared to a meter is similar to the size of a marble compared to the earth. Nanofabrication, arises from nanotechnology, focuses on the methods to build the nanometer scale components, and features with precise accuracy. Through advancements in nanotechnology, photonic devices are tailored to achieve the remarkable control over light at nanoscale dimensions which includes nanostructures for antireflection coatings to enhance the transmission and planar meta lenses to precisely focus the light at certain focal length. Antireflection coatings are used to suppress reflection and increase the optical transmissions, however, these coatings whether it is single layer, or multi-layer cannot withstand the harsh environmental conditions and generally suffers from degradation which deteriorate its optical performances. Inspired from moth eye, subwavelength structures designed periodically were fabricated on the III-V materials, specifically gallium arsenide, to increase its transmittance in the mid-infrared (mid-IR) range wavelengths. Nanopillars structures were fabricated using the top-down approach to pattern the structures directly on the substrate. By varying the pitch of nanostructures, further improvement in the transmission was measured and the results were validated using the rigorous coupled wave analysis (RCWA) model. Similar nanostructures but much smaller in size were written using the E-beam lithography technique on polysilicon coated quartz sample to focus and reflect the light back at the incident direction. The meta lens was first designed by choosing the phase profiles and simulating the different size nano atoms to generate the transmission and phase values chart. Mapping the phase profile against the correct position of meta-atoms helps to produce the desired delays across the lens.Electronic devices, on the other hand, manipulate the movement of electrons instead of light to process the information. Traditional electronic devices such as MOSFETs and BJTs suffers from charge carrier and low electron mobility which makes them less preferred choice for high frequency applications. High electron mobility transistors or simply HEMTs, which possess reduced scattering and high electron mobility, are therefore used for advanced microwave and millimeter applications. Herein, I have also fabricated InP based HEMTs for the terahertz image detection utilizing the techniques such as MBE, PVD, wet etching and lift off.
eIF4E-Dependent Capture of the Monomeric HIV-1 RNA Genome
(2024-01-01) Singh, Karndeep; Summers, Michael F; Chemistry & Biochemistry; Biochemistry
The human immunodeficiency virus type-1 (HIV-1) RNA genome’s 5'- untranslated region (5'-Leader, 5'-L) serves as a master regulator for numerous viral replication processes within a cell such as genome dimerization, splicing, packaging, and translation initiation. This 5'-Leader adopts two conformations dependent on the transcriptional start site usage: 5'-capped RNAs beginning with one guanosine (Cap1G) adopt the dimeric conformation whereas 5'-capped RNAs beginning with two or three guanosines (Cap2G and Cap3G, respectively) adopt a monomeric conformation. Published work from our laboratory revealed that Cap1G leader RNAs sequester the 5'-cap through a coaxial stacking of two 5'-hairpins – the TAR and polyA hairpin. This prevents binding to the human eukaryotic translation initiation factor 4E (eIF4E) cap binding protein – the initial recognition step in cap/eIF4E dependent translation of HIV-1 mRNAs. For the monomeric RNA transcripts, the 5'-cap is exposed and accessible for the recruitment and binding of eIF4E. Therefore, the exposure and sequestration of the 5'-cap (a 7- methylguanosine triphosphate) within the HIV-1 5'-Leader dictates the capture of the RNAtranscripts by cap-dependent translation machinery for translation of viral proteins or genome packaging by the Gag polyprotein, respectively. While it is well-established that cap-dependent translation serves as the primary mechanism of HIV-1 genome translation in eukaryotes, the molecular nature of interactions between Cap3G RNAs and eIF4E remain unknown. Electrophoretic mobility shift assays (EMSAs) and isothermal titration calorimetry (ITC) experiments reveal that the human eIF4E binds to the HIV-1MAL Cap3G RNAs at least 2.5-fold tighter than the 5'-cap, suggesting that RNA elements influence binding of the human eIF4E. Using nuclear magnetic resonance (NMR) spectroscopy with a variety of selectively labeled 1H-, 15N-, and 13C-labeling schemes, we worked to characterize the first three-dimensional structure of a structured 5'-capped RNA – a HIV- 1MAL Cap3G RNA oligo (~13 kDa) – bound to the human eIF4E (~22 kDa). The 5'-cap forms a pi-pi stacking interaction with two tryptophan residues (W56 and W102) while residues of the TAR hairpin forming electrostatic interactions with eIF4E’s exposed charged residues to orient the RNA oligo out of the 5'-cap binding pocket. Surprisingly, the unstructured residues of the polyA region at the 3'-end interact with lysine residues of eIF4E. Our findings reveal that HIV-1 5'-Leader’s structural elements influence the recruitment and binding of eIF4E, suggesting an additional quality control mechanism that HIV-1 uses to ensure the translation of its Cap3G mRNA transcripts into viral proteins.
THE IMPACT OF DEVICE AGING ON THE RESILIENCY OF CRYPTOGRAPHIC DEVICES AGAINST PHYSICAL ATTACKS
(2024-01-01) ANIK, MD TOUFIQ HASAN; Karimi, Naghmeh Dr.; Computer Science and Electrical Engineering; Engineering, Computer
Cryptographic chips offer continued advances in authenticating messages and devices as well as preserving the integrity and confidentiality of sensitive information through the implementation of cryptographic algorithms in hardware. These pieces of silicon combine the benefits of cryptographic applications with the speed and power advantages of hardware implementations. Indeed, cryptographic devices are used as an essential entity in almost all systems that deal with sensitive data, e.g., banking, military, transportation, medical, internet-of-things, and cloud networks. Disruption on these devices can be forced by adversaries to uncover secret information. In fact, the probability of such devices being attacked or hacked is rapidly growing; necessitating the protection of such devices against attacks and in turn secret data leakage. One such attack that can be launched on cryptographic devices is leaking the secret key through side-channel analysis. Indeed, while operating, cryptographic devices leave traces of side-channel information such as power consumption, electromagnetic emanation, running time, and so on. This information can be utilized to conduct statistical analysis, the so-called Side-Channel Attacks (SCA), to retrieve secret information. As mentioned, although cryptographic cores have been developed to maintain security and trust, their physical implementation can be compromised by the adversaries who aim at extracting the sensitive information these chips conceal. Thereby, it is essential to assure the security of the sensitive tasks performed by these circuits and to guarantee the security of information stored within these devices. Security challenges for cryptographic devices can range from the attacks launched to directly retrieve sensitive data (e.g., Side-Channel Analysis attacks and Fault-Injection at tacks) to the attacks in which a cryptographic design is tampered via inserting hardware Trojans to ease information leakage or to cause a denial of service. Protecting cryptographic devices against all such attacks is a major security concern.Side-channel analysis attack via analyzing the device’s power consumption is one of the most popular form of attacks threatening cryptographic devices. Power analysis attacks are carried out by investigating the data being processed as well as the device’s associated power usage. In contrast to power analysis attacks, in the fault injection attacks the adversary has a more active role; injecting faults in the targeted chip to facilitate extracting sensitive data based on a comparison or correlation between the faulty and golden outputs. A wide number of countermeasures have been proposed in recent years to thwart power analysis and fault injection attacks. However, the resiliency of such countermeasures may vary in different operating conditions such as operating voltage, temperature, as well as aging-related degradation. The degradation imposed by aging is considered inevitable for electronic circuits. Therefore, it is highly important to investigate the security of devices that have been used for a while, i.e., have been aged, to ensure their security is not compromised when the devices are aged. This research focuses on the impact of device aging on the security of crypto graphic devices against side-channel analysis attacks, in particular power analysis attacks as well as the resiliency of such devices against fault injection attacks. Accordingly, we first investigated the impact of device aging on the resiliency of unprotected cryptographic devices when subject to profiling and non-profiling power analysis attacks. Then we moved one step forward to analyze the aging impact on the existing countermeasures against power analysis attacks. These countermeasures are mainly classified into two groups: hiding and masking. In our investigation, we conducted power analysis attacks on hiding-protected devices when new and when aged. In particular, we target Sense Amplifier Based Logic (SABL) and Wave Dynamic Differential Logic (WDDL) circuits as the two main existing hiding countermeasures. We showed that, the success rate of the power analysis attacks increases in both SABL- and WDDL-protected circuits over time, i.e., their security diminishes over time. To address the problem, we propose an aging-resilient variation of the SABL circuit to ensure long-lasting security. We also investigated the impact of device aging on several state-of-the-art masking countermeasures tailored to protect against power analysis attacks. The results showed that the protection offered by the state-of-the-art masked devices fluctuates with aging. This may potentially expose the device to vulnerabilities as it ages. Finally, we validated our findings on real silicon, specifically on FPGA. In order to protect cryptographic devices against fault injection attacks, we developed a digital-sensor based failure-detection framework, devised an efficient characterization methodology for the considered sensor, and proposed an aging aware dimensioning algorithm to optimize the sensor hardware based on the whole range of operating conditions. We showed the efficiency of the proposed framework in detecting fault attacks induced by change of temperature, voltage, and clock frequency. These findings were also evaluated using platforms. In sum, our solutions provide long lasting security for cryptographic devices against physical attacks and thus highly benefits the industry and government sectors.
DUNE (Deep UNet++ Ensemble): A Reanalysis-Driven AI-based Climate Forecasting Framework for Monthly, Seasonal, and Annual Predictions
(2024-01-01) Shukla, Pratik Ketanbhai; Halem, Milton; Computer Science and Electrical Engineering; Computer Science
Capitalizing on the recent availability of ERA5 monthly averaged long-term data records of mean atmospheric and climate fields based on high-resolution reanalysis, deep-learning architectures offer an alternative to physics-based daily numerical weather predictions for subseasonal to seasonal (S2S) and annual means. A novel Deep UNet++ Ensemble (DUNE) neural architecture is introduced, employing multi-encoder-decoder structures with residual blocks. When initialized from a prior month or year, this architecture produced the first AI-based global monthly, seasonal, or annual mean forecast of 2-meter temperatures (T2m) and sea surface temperatures (SST). ERA5 monthly mean data is used as input for T2m over land, SST over oceans, and solar radiation at the top of the atmosphere for each month of 40 years to train the model. Validation forecasts are performed for an additional two years, followed by five years of forecast evaluations to account for natural annual variability. AI-trained inference forecast weights generate forecasts in seconds, enabling ensemble seasonal forecasts. Root Mean Squared Error (RMSE), Anomaly Correlation Coefficient (ACC), and Heidke Skill Score (HSS) statistics are presented globally and over specific regions. These forecasts outperform persistence, climatology, and multiple linear regression for all domains. DUNE forecasts demonstrate comparable statistical accuracy to NOAA’s operational monthly and seasonal probabilistic outlook forecasts over the US but at significantly higher resolutions. RMSE and ACC error statistics for other recent AI-based daily forecasts also show superior performance for DUNE-based forecasts. The DUNE model’s application to an ensemble data assimilation cycle shows comparable forecast accuracy with a single high-resolution model, potentially eliminating the need for retraining on extrapolated datasets.
Shigure – A high-performance object storage system with rich metadata provided by a distributed ledger
(2024-01-01) Sebald, Lawrence John; Yesha, Yaacov; Computer Science and Electrical Engineering; Computer Science
Networked computer systems often require massive data storage systems for powering the input needs of the system and providing for a place to store computation results. However, not all networked systems have such high data demands -- sometimes a networked system is just one that holds a family's media and data backups. No matter what the size of the system, a need for data storage will still exist. Where there is data, there is also metadata to describe and help search through the data. Metadata management within networked data storage is a messy proposition, and is often a woefully overlooked component of the system. Typical computer filesystems provide little in the way of metadata support beyond basic file attributes without relying on external software to maintain some sort of index for the user. Modern object storage systems do provide additional metadata support, but do not provide any sort of indexing beyond what a typical filesystem does. I have developed, implemented, and tested Shigure to address the problems of providing adaptable storage with rich metadata support, including indexing. Shigure combines a modern, high-performance object storage system with a distributed ledger for keeping track of and indexing metadata and providing access control to the data stored within the system. This allows Shigure to provide scalable storage with rich metadata indexing support that allows unique access patterns that typical filesystems and object storage systems do not provide without the need for an external database. Shigure also implements a hierarchical model for user permissions that goes beyond the typical idea of users and groups that filesystems provide, allowing for a user-friendly way of sandboxing client programs that wish to make use of the data stored within the system. Shigure has been tested on a variety designs of storage systems to evaluate its performance in various situations -- from a single-node system that might be used by an individual in a home network to a system approximating a big data cloud storage environment with multiple storage nodes communicating over the Internet.
Shaping Ownership in Augmented Reality: The Impact of Annotation Control on Psychological Ownership and Collaboration
(2024-01-01) Seo, Jwawon; Mentis, Helena; Information Systems; Human Centered Computing
Augmented Reality (AR) has emerged as a transformative technology, reshaping the way we interact, collaborate, and perceive our surroundings. This dissertation delves into the intricate dynamics of psychological ownership within AR collaborative workspaces, focusing on the influence of annotation control capabilities. Through a series of controlled experiments using the HoloMentor system, this study examines how different levels of annotation control shape Individual and Collective Psychological Ownership (IPO and CPO) across blended workspaces. The research investigates the mediating and moderating roles of five dimensions of psychological ownership (possession, control, identity, responsibility, and territoriality) and explores how CPO mediates the relationship between annotation control and group processes. Key findings reveal that parallel annotation control consistently fosters the strongest sense of CPO while decreasing IPO across all blended workspace types. A notable spillover effect demonstrates that control over virtual annotations influences ownership perceptions beyond the immediate virtual environment. The comprehensive path analysis uncovers contrasting mechanisms through which parallel and full control influence CPO and collaboration outcomes. In parallel control scenarios, CPO emerges primarily through heightened responsibility, while in full control scenarios, it develops through a stronger sense of personal connection and identification with the task. The study also reveals a paradoxical relationship between individual control and CPO in shared environments, where the increased individual sense of control can sometimes attenuate the positive effect of parallel control on CPO. Furthermore, the research demonstrates that CPO significantly mediates the relationship between annotation control and various group process outcomes, particularly in collaboration quality, performance, and satisfaction. This mediation analysis highlights the importance of fostering CPO in enhancing collaboration, while also revealing that different control modes may be optimal for different aspects of group processes. This research contributes to both theory and practice in Human-Computer Interaction (HCI) and Computer-Supported Cooperative Work (CSCW). It extends our understanding of psychological ownership in AR collaboration, illuminating the complex interplay between system features, psychological factors, and group performance. Additionally, it provides practical design guidelines for creating AR collaboration tools that foster CPO and enhance outcomes. By bridging theoretical insights with design implications, this dissertation advances the development of effective and satisfying AR collaborative systems.
Effectiveness of Ultrathin Al2O3 Capping by Atomic Layer Deposition on the Stability of Single Quantum Dots
(2024-01-01) Sarkar, Yasir; Pelton, Matthew; Physics; Physics
Quantum dots (QDs) possess the capability to function as single photon sources, and their size-dependent optical properties offer a broad range of applications in nanophotonics. However, photo-bleaching and oxidation lead to the degradation of QDs at room temperature, presenting one of the main obstacles to applications. Here, we enhance the stability of single core-shell QDs at room temperature and shield them from the air by using 0.5, 0.7, and 1nm thick capping layers of Al2O3 deposited via atomic layer deposition (ALD). This also enables tip-enhanced strong coupling (TESC) spectroscopy by allowing the formation of a subnanometer plasmonic cavity between a nano-optical antenna and a metal film below the QD. After being exposed to a continuous-wave laser beam of 2.01 mW power for 3.5 hours, photoluminescence (PL) microscopy of QDs under the 0.5nm capping layer demonstrated no reduction in fluorescent QD number compared to a 51% reduction in the number of fluorescent QDs in a sample without such protection. This protection method opens up new possibilities for increasing the fluorescent lifetime of other types of QDs, such as less stable perovskite quantum dots and studying the effect of new capping materials on emitter-plasmon coupling.

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