Overcoming the Common Challenges in Differential Gene Expression Analysis Studies

Huang, Yan ProQuest Dissertations & Theses University of Cali 2019 해외박사(DDOD)

The ability to analyze gene expression data has had a fundamental impact in the biological sciences and on our understanding of the causes and mechanisms of disease. However, a significant statistical challenge is posed by the combination of the small number of replicates together with the large number of genes leading to an undesirable level of misclassified genes when identifying genes with differential expression levels. When multiple gene expression data sets are generated under the same set of experimental conditions, the ques- tion arises as to how to efficiently combine this information. Several methods in the literature have been suggested to aggregate ranked data from multiple sources. We introduce a new classifier, underpinned by Bayesian principles, called Peer Reinforced Ranker (PR-Ranker) which uses density estimation to approximate the probability that a gene is differentially expressed given a collection of ranked lists.Our classifier is amenable to theoretical analysis when the number of genes and lists is large using the theory of large deviations. Under modest technical assumptions we show that asymptotically PR-Ranker has the smallest loss of any rank aggregation procedure. Moreover, we prove that other more ad hoc methods, such as Borda, have a strictly higher asymptotic rate of loss.While the theoretical results are asymptotic, we perform a series of simulation studies that demonstrate that our classifier outperforms existing methods on datasets of realistic size for biological data. Furthermore, we show that the outperformance is even greater when the lists exhibit varying levels of noise or when some sources are corrupted. PR-Ranker automatically adapts to varying data quality and efficiently combines the data from different sources. Finally we apply PR-Ranker to a gene expression data set in a preeclampsia study. The top ranked genes identified were known to be biologically relevant to preeclampsia and our method achieved a substantially higher Consistency Index than other rank aggregation procedures.

Parent-Child Language Gaps and Empathic Accuracy in Conflict Discussions: A Mixed Methods Study of Bilingual Chinese Immigrant Parent-Child Dyads

Huang, Cindy J Columbia University ProQuest Dissertations & These 2025 해외박사(DDOD)

Chinese immigrant families in the United States are often bilingual, defined as having the knowledge of two languages (e.g., English and a heritage language such as Chinese) and using those languages in everyday life with varying proficiency levels for each language. These varying proficiency levels in both languages, otherwise termed language gaps (i.e., language matches or mismatches), have been shown to impact parent-child relationships. Language gaps may contribute to communication difficulties and increased family conflict during middle childhood (roughly ages 6-12), which places school-age children at increased risk for poorer psychological outcomes. Some of these communication challenges may be due to differences in empathic accuracy, defined as the degree to which a person accurately infers another person's thoughts and feelings. Chinese immigrant parents and children who misinterpret one another's emotions and demonstrate lower empathic accuracy may experience increased family conflict. Observations of conflict discussions are necessary to explore these constructs in real time, but many existing studies have not been able to examine parent-child conflict discussions as they occur due to the sensitive nature of these conversations, and especially not in bilingual Chinese immigrant families.Utilizing multidisciplinary theoretical frameworks and multi-informant perspectives, this dissertation study used a convergent mixed methods design to examine how English and Chinese language proficiency gaps (i.e., match/mismatch) among Chinese immigrant parents and their school-age children are associated with parent-child empathic accuracy and evaluations of their conflict discussion. This study had two aims: 1) examine how parent-child language proficiency gaps in English and Chinese are associated with parent and child empathic accuracy and conflict evaluations, and 2) identify examples and patterns of conversational practices used between parents and children during the conflict discussions to corroborate the aforementioned relationships.Participants in the quantitative portion of the study were the full sample of 169 children between the ages of 7-11 (M = 9.16 years, SD = 1.05) and one of their parents (Mage = 40.93 years, SD = 4.88). Parents completed self-report questionnaires and interviews indicating their demographic information as well as parent and child language proficiency, and both parents and children self-reported their empathic accuracy and conflict evaluation ratings. Participants in the qualitative portion of the study (n = 9) were identified from the full sample using random sampling based on the parent-child language match (i.e., match in low Chinese proficiency, match in high Chinese proficiency, match in low English proficiency, match in high English proficiency). To examine how parent-child language proficiency gaps in English and Chinese are associated with parent and child empathic accuracy and conflict evaluations, Response Surface Analysis (RSA) plots were utilized to examine the nonlinear relationships between parent-child language proficiency on the outcomes of interest. Path analyses using structural equation modeling examined the mediating role of parent-child empathic accuracy on the associations between parent-child language proficiency in English and Chinese and their conflict evaluations. To identify examples of conversational practices used between parents and children in conflict discussions, Conversation Analysis, an applied linguistics methodology, was used to identify themes of conversational practices that helped to explain the quantitative results. Results through Response Surface Analysis (RSA) plots indicated that 1) compared to parent-child dyads with match in low English proficiency, parents in parent-child dyads who matched at higher levels of English proficiency exhibited higher levels of empathic accuracy, 2) compared to parent-child dyads in which parent English proficiency is higher than the child's English proficiency, parents in parent-child dyads in which child English proficiency was higher than parent English proficiency exhibited higher levels of empathic accuracy, and 3) among parent-child dyads who matched at higher levels of English proficiency, children exhibited higher levels of empathic accuracy than among parent-child dyads who matched at lower levels of English proficiency. Path analyses results indicated that children with higher English proficiency reported a more positive conflict evaluation when their parents exhibited greater empathic accuracy. Conversation Analysis (CA) was used to identify the conversational practices that parents and children used during the conflict discussions that corroborated the quantitative findings. The integration of quantitative and qualitative findings identified domains and themes of conversational practices that help to explain parents' greater empathic accuracy and children's more positive conflict evaluations.These findings have implications for future research and interventions addressing parent-child relationships and communication in bilingual Chinese immigrant families. Attention to the language gap and use among bilingual Chinese immigrant parents and their school-age children may generate more insight into immigrant family dynamics and culturally relevant ways to strengthen parent-child relationship quality within these families.

Combining Theory and Experiment in Pt-Based Catalysts Design for Energy Conversion

Huang, Jin ProQuest Dissertations & Theses University of Cali 2021 해외박사(DDOD)

Analyzing ESG Practice of Chinese Energy SOEs in Southeast Asia under the Green Belt and Road Initiative : Focusing on Coal and Hydropower Sector

HUANG 서울대학교 대학원 2024 국내석사

In light of the increasing significance of Environmental, Social, and Governance (ESG) principles, the Belt and Road Initiative (BRI) has faced criticism for ESG risks. The study explores how Chinese state-owned enterprises (SOEs) implement Beijing’s ESG principles within the energy sectors of coal and hydropower in Southeast Asia. It assesses the alignment of these practices with Beijing's policies and examines whether these practices adhere to or deviate from the established guidelines. Incorporating a dual framework of Corporate Social Responsibility (CSR) and Corporate Social Opportunity (CSO), this research analyzes how corporate actions meet regulatory expectations and leverage opportunities for promoting sustainable development. The findings reveal certain efforts, including advancements in clean energy investments and infrastructure enhancements, which contribute positively towards environmental conservation and economic growth. However, significant discrepancies remain in adhering to local environmental laws, conducting thorough environmental assessments, and maintaining transparency, highlighting the need for more stringent and application of ESG standards. In addition, there is a significant need to enhance both the employment standards offered and the adequacy of compensation for land usage and the social impacts caused by these projects. Addressing these issues will enable Chinese SOEs to better meet their ESG commitments, ensuring that their projects are economically viable, socially responsible, and environmentally sound. Enhancing these aspects of ESG implementation will further align corporate actions with policy ambitions, improving the overall sustainability and acceptance of these international investments. Overall, the implementation of ESG policies by Chinese firms in the coal sector primarily reflects a traditional CSR approach, focused on damage control and compliance. This indicates a need for stronger integration of CSO principles to shift these engagements from merely reactive measures to proactive, strategic actions that foster long-term sustainability and community development. Similarly, the hydropower sector in Southeast Asia under the BRI shows alignments with both CSR and CSO, though these efforts remain limited. While there are instances of environmental management and community support, the sector still largely emphasizes reactive CSR measures over proactive CSO strategies. To achieve truly sustainable outcomes, a greater emphasis on integrating and balancing these approaches is needed, particularly in enhancing genuine community participation and ensuring fair compensation and resettlement practices. The study argues for an enhanced integration of CSO principles, recommending that Chinese SOEs shift towards more proactive and strategic engagements that deeply embed sustainability into corporate strategies and community interactions. By strengthening the balance between CSR and CSO, these enterprises can mitigate environmental and social risks while maximizing benefits to local communities, achieving more robust sustainable outcomes. Key words: Belt and Road Initiative; Energy Sector; ESG; CSR; CSO Student number: 2022-24903 환경, 사회, 경영(ESG)의 중요성이 높아짐에 따라 일대일로 (Belt and Road Initiative) 정책은 ESG 위험에 대한 비판을 받고 있다. 본 연구는 중국 국영기업(SOE)들이 동남아시아의 석탄 및 수력발전 에너지 부문에서 어떻게 녹색 일대일로의 ESG 정책을 구현하고 있는지에 대해서 탐구하고 중국 ESG 정책과 국영기업의 실제 관행 사이의 일치 여부를 조사하며 이러한 관행이 ESG 지침을 얼마나 준수하는지를 평가한다. 또한, 본 연구는 기업들의 ESG 행동이 사회적 책임(CSR)인지 사회적 기회(CSO)인지를 분석한다. 본 연구 결과에서는 그린 에너지 및 인프라 개선과 같은 긍정적인 노력이 있음에도 불구하고 여전히 중대한 격차가 존재한다는 것을 보여준다. 그래서 현지 환경 법규 준수, 철저한 환경 평가 실시 및 투명성 유지에 있어 상당한 차이가 있어 ESG 기준의 보다 엄격하고 일관된 적용을 강조하고 고용 기회의 질과 토지 사용에 대한 보상 적정성도 상당한 개선이 필요하다. 이러한 문제를 보안해야 중국 SOE들은 ESG 정책을 더 잘 이행하고, 정책 목표와 기업 행동을 더 잘 일치되게 하여 전반적인 지속 가능성과 수용성을 높일 수 있다. 중국 기업의 석탄 부문 ESG 정책 구현은 주로 피해 통제 및 준수에 중점을 둔 전통적인 CSR 접근 방식을 반영한다. 이는 이러한 방식을 단순히 반응적인 조치에서 장기적인 지속 가능성과 지역 사회 개발을 촉진하는 전략적 행동으로 전환하기 위해 CSO 원칙의 강력한 통합이 필요함을 시사한다. 마찬가지로, 일대일로 하 수력 기업들도 CSR과 CSO의 조화가 보이지만 CSO에 대한 노력은 여전히 제한적이다. 환경 관리 및 지역 사회 지원의 사례가 있지만, 기업들이 여전히 적극적인 CSO 전략보다 반응적인 CSR 조치를 강조한다. 진정으로 지속 가능한 결과를 달성하려면 이러한 접근 방식을 통합하고 균형을 맞추는 데 더 큰 비중을 두어야 한다고 제기한다. 본 연구는 CSO 원칙의 향상된 통합을 주장하며, 중국 SOE들이 지속 가능성을 기업 전략 및 지역 사회 상호 작용에 깊이 통합하는 보다 적극적이고 전략적인 관여로 전환할 것을 권장한다. CSR과 CSO 간의 균형을 강화함으로써 기업은 환경 및 사회적 위험을 완화하면서 지역 사회에 대한 이익을 극대화하여 더 강력한 지속 가능한 결과를 달성할 수 있다. Key words:녹색 일대일로; 에너지 부문; 환경, 사회, 경영(ESG); 사회적 책임; 사회적 기회

Investigation of Structure-Mechanics-Property Relations in Heart Valve Tissues

Huang, Siyao North Carolina State University 2014 해외박사(DDOD)

The microstructure and the mechanical property of the heart valve are physically critical factors in modeling the valve tissue equivalent. The heart valve tissue has a complex microstructure primarily containing collagen fibers and valve interstitial cells (VICs). The extracellular matrix (ECM) of the heart valve tissue, where collagen is the main component, provides strength to support the structure of the tissue. The inhomogeneity of the collagen fiber architecture gives rise to the nonlinear anisotropic material property of the tissue. Besides, to respond mechanical loads, VICs mediate a series of bioregulations for ECM remodeling such as homeostasis, collagen synthesis, and collagen degradation through collagen fibers, which further result in changes of the material behavior corresponding to mechanical stimulation. Due to the inhomogeneous architecture of collagen fibers and randomly distributed cell population, the mechanical behavior of the heart valve tissue becomes more complicated during cardiac cycles. Heart valves open and close correctly and persistently during cardiac systole and diastole for blood circulation. It is a widely acknowledged health concern that heart valve diseases lead to defective structures and improper functions of heart valves to directly influence the blood circulation and the heart workload. To date, at least 250,000 people are suffering heart valve diseases in the United States, and the population keeps rising. Studies have indicated that heart valve diseases are caused by the disrupted tissue homeostasis under a variety of pathological conditions, resulting in alterations in heart valve microstructures, mechanical properties, and other biomechanical regulations. Severe collagen depletion is one of disordered tissue remodeling caused by matrix metalloproteinases (MMPs) that pathologically induces matrix destruction, changes the viscoelastic property of the heart valve tissue, further affects cellular regulations mediated by VICs, and even leads to heart valve diseases. With application of collagenase simulating collagen degradation by MMPs, this study focuses on characterizing stress-relaxation behaviors of fresh porcine heart valve tissues and collagenase-treated ones under different stretching conditions. Moreover, the collagen concentration is measured to provide biochemical information related to the mechanical stress relaxation. The results reveal the sensitivity of collagen fibers to proteolytic degradation. The decrease in the stress state of the heart valve tissue is associated with the stretching level and the collagenase concentration. Stress is further decreased after applying collagenase, and a larger stress drop results from a higher strain level and/or a higher collagenase concentration. Therefore, the current study provides important links between several factors: collagen degradation, activities of matrix metalloproteinases, collagen fiber directions, and mechanical stimulations. It is known that heart valves constantly experience different stress states during cardiac cycles; however, how these mechanical stimuli translate into extracellular matrix remodeling, cellular mechanotransduction, cell migration, and collagen synthesis are still unclear. Although the computational simulations of heart valve tissue have been widely studied via the homogenization of collagen fiber distribution or the simplified representation of the highly heterogeneous collagen fiber network excluding the cell population, the matrix-to-cell stress transfer is underestimated. Meanwhile, VIC regulations have been investigated from cells generally isolated from the matrix prior to adhesion molecule characterization; thus, tissue-cell mechanical interactions have not been fully characterized in the native in vivo environment in which they normally operate. To demonstrate heterogeneously distributed collagen fibers responsible for transmitting forces into cells, this study introduces a virtual experiment via an image-based finite element analysis incorporating a histological photomicrograph of a porcine heart valve tissue. Furthermore, the evolution of stress fields at both the tissue and cellular levels is reported to contribute toward refining our collective understanding of valvular tissue micromechanics while a computational tool is provided to further study of valvular cell-matrix interactions.

Modeling Diffusion Induced Stresses for Lithium-Ion Battery Materials

Chiu Huang, Cheng-Kai North Carolina State University 2014 해외박사(DDOD)

Advancing lithium-ion battery technology is of paramount importance for satisfying the energy storage needs in the U.S., especially for the application in the electric vehicle industry. To provide a better acceleration for electric vehicles, a fast and repeatable discharging rate is required. However, particle fractures and capacity loss have been reported under high current rate (C-rate) during charging/discharging and after a period of cycling. During charging and discharging, lithium ions extract from and intercalate into electrode materials accompanied with the volume change and phase transition between Li-rich phase and Li-poor phase. It is suggested that the diffusion-induced-stress is one of the main reasons causing capacity loss due to the mechanical degradation of electrode particles. Therefore, there is a fundamental need to provide a mechanistic understanding by considering the structure-mechanics-property interactions in lithium-ion battery materials. Among many cathode materials, the olivine-based lithium-iron-phosphate (LiFePO4) with an orthorhombic crystal structure is one of the promising cathode materials for the application in electric vehicles. In this research we first use a multiphysic approach to investigate the stress evolution, especially on the phase boundary during lithiation in single LiFePO4 particles. A diffusion-controlled finite element model accompanied with the experimentally observed phase boundary propagation is developed via a finite element package, ANSYS, in which lithium ion concentration-dependent anisotropic material properties and volume misfits are incorporated. The stress components on the phase boundary are used to explain the Mode I, Mode II, and Mode III fracture propensities in LiFePO4 particles. The elastic strain energy evolution is also discussed to explain why a layer-by-layer lithium insertion mechanism (i.e. first-order phase transformation) is energetically preferred. Another importation issue is how current rate (C-rate) during charging/discharging affects diffusion induced stresses inside electrode materials. For the experimental part we first conduct charging/discharging under different C-rates to observe the voltage responses for commercial LiFePO4 batteries. Then Time-of-Flight Secondary Ion Mass Spectrometry technique is applied to measure the lithium ion intensities in different C-rate charged/discharged samples. These experimental results could be used to support that a more significant voltage fluctuation under high C-rates is due to different lithium insertion mechanisms, rather than the amount of lithium ions intercalated into electrode materials. Thus the investigation of C-rate-dependent stress evolution is required for the development of a more durable lithium ion battery. In this dissertation, we extend the single particle finite element model to investigate the C-rate-dependent diffusion induced stresses in a multi-particle system. Concentration dependent anisotropic material properties, C-rate-dependent volume misfits and concentration dependent Li-ion diffusivity are incorporated in the model. The concentration gradients, diffusion induced stresses, and strain energies under different C-rates are discussed in this study. Particle fractures have been observed in many experimental results, in this study we further discuss the effect of the crack surface orientation on the lithium concentration profile and stress level in cathode materials. The results of this dissertation provide a better understanding of diffusion induced stresses in electrode materials and contribute to our fundamental knowledge of interplay between lithium intercalations, stress evolutions, particle fractures and the capacity fade in lithium-ion batteries.

Molecular scale materials assembly investigated by atomic force microscopy

조강래 ProQuest LLC UMI Dissertation Publishing 2011 국내박사

Does institutional cross-ownership reduce corporate shadow banking activities?

Xu, Zhibo Woosong University 2025 국내박사

Balancing rigidity and flexibility : the dual mechanisms of authoritarian leadership and self-risk perception in driving success for the Belt and Road Initiative megaprojects

Gong, Yunpeng Woosong University 2025 국내박사

ESG and non-financial corporate shadow banking : an inverted u-shaped relationship

Gan, Zhongxin Woosong University 2025 국내박사