UC Riverside

The Shan State of Eastern Myanmar forms the western portion of the Sibumasu Terrane, an originally peri-Gondwanan microcontinental fragment that also includes northwest and peninsular Thailand, peninsular Malaysia, and the Baoshan block of western Yunnan. Various lines of evidence, including shared trilobite fauna, support the close association of the Sibumasu Terrane with western Australia, North China, and South China, as well as with more distant terranes such as Laurentia and Kazakhstan. Although the presence of Cambrian trilobites in Sibumasu has been documented from Baoshan and the Tarutao Group of Thailand since the mid-1900s, and Cambrian trilobites have been known from Myanmar’s upper Molohein Group (Furongian-Tremadocian) since the 1970s, formal descriptions of Myanmar’s Cambrian trilobite fauna remained unpublished until 2021. A comprehensive systematic description of these trilobites is thus necessary for a more complete understanding of the biostratigraphy, paleogeography and evolution of peri-Gondwanan terranes, as well as of the geochronology and biostratigraphy of the latest Cambrian. In 2016 and 2020, field expeditions to the southern Shan State yielded abundant trilobite material from 12 localities representing the Myet-Ye formation of the upper Molohein Group, only three taxa of which have been described in a prior publication (Wernette et al., 2021). Here I present an integrated, complete systematic description of the Cambrian trilobite fauna of Myanmar collected to date. I describe 20 different trilobite taxa from the Myet-Ye material. 17 of these taxa have been identified to the genus level, and 11 have been further resolved to a species level. 2 new species of saukiid, Prosaukia kyaingseini and Diemanosaukia sp. 1, are described, as well as a potentially new species of tsinaniid, Tsinania? sp., though existing material is not sufficient for further specific diagnosis. The trilobite fauna of the Shan State largely corresponds to the Eosaukia buravasi and Asaphellus charoenmiti biozones of Thailand, representing the latest Cambrian and Early Ordovician respectively. The similarities between trilobite genera of the Shan State and those of Ko Tarutao, Baoshan, and western Australia are significant; however, other genera common to these areas, such as Quadraticephalus, have yet to be recovered in the Shan State.

The unicellular protozoan, Plasmodium falciparum, is the human malaria-causing parasite responsible for over half a million deaths each year. P. falciparum has a complex life cycle, alternating between human and invertebrate hosts, and is capable of not only evading the host immune responses but also developing resistance to all clinically administered treatments. Consequently, malaria remains a persistent global health concern. Recent advances in omics-based technologies, improved sequencing platforms, and enhanced CRISPR-based gene editing tools have opened new avenues for understanding the parasite biology, identifying new therapeutic strategies and combating the spread of malaria.This report delves into the systems-wide approaches employed to explore the drug mechanism of action of a new compound, MED6-189, a new analogue of the kalihinol family of isocyanoterpene natural products, effective against drug-sensitive and -resistant P. falciparum strains. We also use advance multi-omics strategies to identify and functionally characterize new potential drug targets involved in gene regulation. Those included targeting proteins coding for chromatin remodeling complexes or better understanding the role of long non-coding RNAs (lncRNA) in the parasite life cycle progression. In essence, the goal of my PhD thesis was to identify promising and alternative targets to curb the spread of malaria, either through the development of new antimalarial agents or the discovery of novel, unexploited potential targets critical for the parasite's survival.

Amid escalating energy demands, the significance of thermoelectric applications, which convert waste heat into electrical energy, is receiving heightened attention. This dissertation delves into the synthesis and thermoelectric properties of layered and complex-structured materials, focusing on enhancing thermoelectric performance through two key approaches: improving the power factor and reducing lattice thermal conductivity.

ZrTiSe4, a layered van der Waals transition-metal chalcogenide, exhibits a high Seebeck coefficient of –202 μV K−1 at 300 K despite being a semimetal. This unique behavior is attributed to the triple valley degeneracy of conduction bands at the M point, leading to a large effective mass of the density of states, as demonstrated through a combination of theoretical and experimental studies. ZrTiSe4 serves as a model system to illustrate how band convergence can enhance the power factor. Additionally, its low thermal conductivity, resulting from low sound velocity, phonon-boundary scattering, and the formation of a solid solution with randomly occupied Zr and Ti atoms, positions ZrTiSe4 as a promising material for thermoelectric applications.

Fe2Ge3 with an incommensurate Nowotny chimney-ladder compound also exhibits significant thermoelectric potential. Single crystals of Fe2Ge3 grown by the chemical vapor transport method exhibit a low, nearly temperature-independent thermal conductivity of 1.9 W m−1 K−1 at 300 K. The low thermal conductivity is attributed to the scattering of heat carrying acoustic phonons by low-energy optical phonons and the involvement of degenerate overlapping optical vibrational modes known as diffusons, which contribute to thermal transport through a hopping mechanism. This material is used to demonstrate the intrinsic thermal transport mechanisms in complex crystal structures.

This dissertation also presents the synthesis and characterization of other transition-metal chalcogenides, including ZrSe3 and ZrTiTe4. Thermal transport measurement on ZrSe3 suggests that optical phonons can contribute to thermal transport at high temperatures. Measurements of Hall resistivity and the Seebeck coefficient on ZrTiTe4 reveal a bipolar carrier transport in this material, which has potential applications in transverse thermoelectric devices.

Point-of-care (POC) diagnostics have emerged as a critical tool in modern healthcare and agriculture, offering the potential to revolutionize disease detection and management, particularly in resource-limited settings. By enabling rapid, on-site testing without the need for specialized laboratory equipment, POC diagnostics can significantly improve patient outcomes, reduce healthcare costs, and enhance disease surveillance capabilities. Polydiacetylenes (PDAs) are a unique class of polymers with conjugated backbones that undergo a colorimetric blue-to-red transition in response to various stimuli, making them promising candidates for simple, visual detection systems. This dissertation explores the development and optimization of PDA-based sensors for point-of-use diagnostic applications. A systematic investigation of liposome synthesis parameters is conducted, identifying optimal conditions for uniform and responsive PDA assemblies. The effects of diacetylene monomer structure and lipid doping on sensor performance are examined, revealing that shorter alkyl chains and moderate lipid incorporation enhance sensitivity while maintaining stability. Efforts to develop antibody-functionalized PDA sensors for detecting plant pathogens and model proteins are described, highlighting both the potential and limitations of this approach. To overcome challenges encountered with antibody-based systems, an alternative strategy using small-molecule ligands for protein detection is explored. Throughout the work, emphasis is placed on creating robust, reproducible protocols suitable for point-of-use applications. The insights gained from this research contribute to the broader understanding of PDA-based biosensors and provide a foundation for their future development as accessible diagnostic tools for healthcare and agricultural applications.

Modern software development increasingly relies on software supply chains, with third-party libraries constituting a significant portion of many projects. However, the complexity of dependency relationships and the lack of transparency in software make identifying and fixing vulnerabilities challenging and costly. For example, the average cost of a Log4j incident response has reached $90,000, and nearly 40% of applications still use vulnerable Lo4j two years after the vulnerability was disclosed. A Software Bill of Materials (SBOM), which lists the dependencies used to build software, has been proposed to enhance software visibility and aid in vulnerability detection. Despite this, there is not yet an accurate SBOM generation solution for both source code and binary. Current SBOM generators focus solely on metadata and produce inconsistent SBOM files, while the existing SBOM generators for binary files are either too slow or inaccurate.

In this thesis, we propose an accurate and fast SBOM generation approach for both source code and binary. First, to improve SBOM generation for source code, we conducted a differential analysis to compare and understand how the existing SBOM generators work and why they behave so differently. We found that these generators support only a subset of common metadata, and their self-implemented parsers for metadata have incomplete syntax supports, leading to erroneous SBOM results. We propose using package managers to simulate dependency installation for metadata-based SBOM generation. Second, we introduce DeepDi, a novel graph neural network-based disassembler that is both accurate and efficient for better SBOM generation for binaries. Our study showed that disassembly is often the bottleneck of binary analysis tasks, consuming up to 90% of processing time. DeepDi improves efficiency by hundreds of times compared to commercial disassemblers and is as accurate or better than them. Third, to further improve the accuracy of SBOM generation from binaries, we propose GrassDiff, a novel learning-free graph-matching algorithm that effectively and efficiently identifies static-linked libraries in large binaries.

Spin-based electronics or spintronics bear the potential to become an alternative paradigm to the traditional transistor-based electronics that is currently facing significant challenges related to energy efficiency, heat management and speed limitations. Understanding spin dynamics is essential for functionalizing spintronic devices. Frequency of operation of spintronic devices is in the range of GHz for ferromagnetic (FM) systems, and potentially THz for anti-ferromagnetic (AFM) systems.A segment of my research examines bilayer nanostructures comprising YIG and Ni for potential application in energy-efficient spintronic devices. Microwave emission spectroscopy performed on these hybrid magnetic nanodevices in perpendicular geometry showed the presence of auto-oscillatory mode driven by the spin-Seebeck effect– an effect that re-uses waste heat in the nanodevice to operate it. We further observed a substantial non-linear frequency shift at low magnetic fields. This work establishes a proof of concept for utilizing spin-based mechanisms in the pursuit of energy-efficient spintronics solutions. To push the boundaries of spin-based applications, AFM have been proposed. AFM operates in sub-terahertz to terahertz frequency range compared to FM at gigahertz frequency range. AFMs are also robust to external magnetic perturbations because of their zero net magnetization. In this dissertation, I translate the techniques and knowledge from FM systems to AFM systems and study the coherent spin dynamics in the bulk insulating antiferromagnetic systems. The magneto-resistive (MR) method is used to detect antiferromagnetic resonance (AFMR) in bulk Cr2O3 and Pt micro-structure device of size 10µm × 200µm. The successful detection of MR-AFMR set up the path to dive into the nanoscale AFM system. We achieved electrical detection of antiferromagnetic resonance signal in a nanodevice of dimension 200nm × 200nm. Additionally, we are also able to electrically detect the AFMR signal in Fe2O3/Pt AFM system. The analysis of the study of the AFMR signal and the angle between the microwave current flow and the c-axis of the anti-ferromagnetic device suggest that the resonance signal is dominated by the spin-torque excitation rather than inductive/Oersted excitation. The results of this work pave the road toward nanoscale AFM spin-torque devices and applications. As a prospect, we evaluate an alternative approach that relies on inductive excitation of AFM spin dynamics but is less restrictive to the miniaturized device size. We propose and develop integration of omega-shaped planar micro-resonator with micro-scale AFM structures. This work explores alternative pathways for hybrid AFM-superconductor systems and will broaden the experimental palette for the studies of AFM spin dynamics.

Hair follicles (HFs) are mini-organs in skin who undergo cyclic growth. Duringthe anagen phase, hair shaft is produced from the bottom part of a HF, referred to as the hair bulb. Proper regulations of the HF bulb cell fate decisions are crucial to maintain an anagen HF, therefore guarantees the continuous production of hair. Recent experiments have provided evidence on how HF bulb is replenished during anagen, and how cells make their fate decisions according to their positions, leading to the HF concentric layered differentiation. In this paper, we develop a hybrid multiscale computational model on HF bulb, integrating cell divisions and movement, diffusive signaling dynamics and intra-cellular gene regulations. Using our model, we first investigate the HF replenishment dynamics driven by different cell dividing strategies, showing that signaling-driven cell division may lead to efficient replenishment dynamics. Next, we use the model to test the primed cell fate decision mechanism, and explore other candidate mechanisms that may contribute to a perfect HF concentric layered differentiation.

This dissertation focuses on the mystical monist Sufi philosophy known as the “Unity of Being”(waḥdat al-wujūd) in the early modern Ottoman and Mughal Empires. Following the death of its supposed founder, Ibn al-’Arabī (d. 1240 c.e.), this philosophy flourished and spread to all corners of the Islamicate world while gaining followers and critics alike. Especially in the 17th century, debates surrounding this system of thought can tell us much about Sufism as well as the history of empire, changing religious demographics, and contests over political and religious authority. Proponents and detractors of this philosophy have been quick to point out that the boundaries between religions become complicated by the universalizing claims of this worldview. Adherents to the doctrine of waḥdat al-wujūd like Şeyh Bedreddin (d.1421 c.e.) led Muslims and Christians alike in a revolution, the Mughal prince Dārā Shikūh (d. 1659 c.e.) used this philosophy to justify his pluralistic religious project, and ‘Abd al-Ghanī Nābulusī (d.1731 c.e.) rigorously defended this ideology against a puritanical faction known as the Ḳāḍīzādelis while maintaining cordial relations with non-Muslims. This study not only looks at the anti-Sufi opponents of this philosophy but also examines Aḥmad Sirhindī ’s (d. 1624 c.e.) rejection of waḥdat al-wujūd and challenges the primacy of his intervention in the Naqshbandi Sufi order. By exploring case studies where mystical monism was debated, it becomes apparent that anxieties over the demarcation between Islam and non-Muslim religions are at the crux of what makes this philosophy so controversial, and that its defenders attempt to navigate a course between the particulars of Islam and the universalizing worldview of mystical monism.

Asset liquidity, crucial for understanding asset pricing anomalies and the transmission mechanism of monetary policy, is significantly interacted with information frictions among market participants. Employing the New-Monetarist framework pioneered by Lagos and Wright (2005) and Rocheteau and Wright (2005), this dissertation comprises three essays investigating the presence and acquisition of private information and its impact on asset liquidity. Chapter 1 provides an overview.

Chapter 2 explores the implications of private information acquisition for asset liquidity within a New-Monetarist model. The model incorporates a bargaining protocol with private information and strategic information acquisition decisions, revealing how economic fundamentals and monetary policy influence private information acquisition. A non-monotonic effect of nominal interest rates on asset liquidity is identified, with insights applied to interpret the 2007-2008 financial crisis.

Chapter 3 extends the model to account for hidden information status in real-world markets. This chapter uncovers strategic behaviors among dealers under hidden information status, leading to equilibrium configurations characterized by separating, semi-pooling, and pooling equilibria. Notably, a non-monotonic response of private information acquisition to monetary policy emerges, contrasting with Chapter 2.

With the rising portion of international investment executed by portfolio managers, Chapter 4 addresses the home bias puzzle in international finance literature by considering the influence of delegated portfolio management on international portfolio allocation strategies. Furthermore, I discuss the future research agenda and the development of the existing literature.

Effective classroom management (CM) is critical to promoting student success, as there is a clear connection between teacher CM practices and student academic, social, and behavioral outcomes. Research demonstrates that children spend more time academically engaged, progress more rapidly, and have higher levels of academic achievement when they are in a well-managed classroom. Despite the importance of CM and its influence on student outcomes, pre- and in-service training in this area appears lacking. To address this issue, some scholars have proposed the use of a data-driven, multi-tiered approach to support educational service delivery, including professional development (PD) activities designed to promote use of effective CM practices. However, in current, applied practices, PD opportunities fall largely at two ends of the spectrum of time, energy, and resources required. The goal of the present study was to explore the utility of a moderately intensive, Tier II level, PD approach within a multitiered system of educator support (MTSES) framework. A combined multiple baseline, ABC single case design across participants was used to evaluate the effects of two, PD approaches, performance feedback (PF) and performance feedback with self-monitoring (PF+SM), on the CM practices of four volunteer participants. Classroom management was measured through daily 20-minute observations using the Direct Behavior Rating- Classroom Management (DBR-CM). During the first intervention phase, participants received brief verbal and visual performance feedback before each observation period and during the second intervention phase, a self-monitoring component was added to these procedures. Results of visual and empirical analyses indicated that the PF only intervention was effective in increasing teachers use of evidence-based CM practices as measured by DBR-CM total score. Slight improvements in CM practices from the first intervention to the second intervention (PF + SM) were observed for individual participants but no effect of this intervention was demonstrated. Several important limitations and suggestions for future research are discussed.