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Probing Microscopic Properties Of Next Generation Materials Using Coherent Vibrational And Electronic Spectroscopy
Get PDFThe dissertation research focused on understanding the relationship between the chemical structure of organic molecules and their photophysical properties, particularly examining coherent electronic and vibrational coupling within and between molecules, with implications for next-generation energy technologies. In Chapter 2, we employed both steady-state and transient optical and magnetic spectroscopic techniques to understand the electronic delocalization in both singlet and triplet exciton delocalization in weakly bound porphyrin dimeric molecules. Our results highlight that the delocalization of singlet exciton delocalization does not guarantee the delocalization of triplet excitons between weakly bound porphyrin macromolecules. Our studies demonstrate how one can access the electronic delocalization of macromolecular systems central to the next-generation photochemical, photo-catalytic, and information-processing technologies using optical and magnetic spectroscopic techniques.
In Chapter 3, we investigated how strong light-matter coupling in porphyrin-based chromophores within Fabry-Pérot microresonators reduces the energetic disorder of excitons, crucial for integrating these materials into optoelectronic technologies. By studying cavity polaritons from distinct porphyrin dimers, we observed dispersive peak widths for lower polariton states, indicating potential enhancements in the coherence of hybrid molecular materials. Differences in excitonic disorder suppression among samples are attributed to microscopic light-matter interactions, particularly photonic exchange. Our findings highlight the potential of cavity polariton formation to enhance coherence in hybridmolecular materials, offering insights for future design strategies. In Chapter 4, we employed temperature-dependent Raman spectroscopy alongside density-functional theory calculations to investigate the anharmonic properties of 2-methylbenzimidazole. Our study aimed to understand how vibrations in this material contribute to the proton tautomerism (PT) mechanism responsible for ferroelectric switching. We developed a method based on standard anharmonic theory to analyze cubic and quartic couplings to low-frequency lattice vibrations, which affect intramolecular ring vibrations modulating carbon-nitrogen double bonds central to the PT mechanism. Our findings underscore the significance of vibrational spectroscopy in revealing how intermolecular interactions influence the structural dynamics of materials essential for sustainable information storage and nonlinear optical technologies
A Robust Framework For Designing Leagile Supply Chains-Baha Mohsen
No full textA ROBUST FRAMEWOR FOR DESIGNING LEAGILE SUPPLY CHAINS By BAHA M. MOHSEN MAY 2024 Advisor: Prof. Ratna Babu Chinnam Major: Industrial and Systems Engineering Degree: Doctor of Philosophy This dissertation presents the development of a robust framework for the design and implementation of Leagile supply chains, which synergizes the lean approach of minimizing waste with the agility required for rapid response to market dynamics. Acknowledging the burgeoning complexity in global supply chains, this study addresses the gap in existing frameworks that fail to integrate the full breadth of lean and agile principles into a unified, operational system. The research commences with a comprehensive literature review that charts the evolution of supply chain management and highlights seminal works underpinning lean and agile principles. It scrutinizes previous models, noting a significant void in research concerning Leagile supply chain frameworks, especially in the areas of performance measurement, digital transformation, sustainability, and risk management. To bridge these gaps, the dissertation proposes a conceptual framework that includes the selection of relevant KPIs for Leagile supply chains, the establishment of a Balancing Point Scale, an Assessment Framework with a composite performance index, and a suite of Improvement Actions and Optimization Models for scenario planning and risk evaluation. Empirical validation of the framework is conducted through two distinct industry case studies—Ducab Company and Julphar-Gulf Pharmaceutical Industries—providing a practical perspective on the framework\u27s adaptability and effectiveness. The analysis of these case studies offers insights into the real-world application of the framework, contributing valuable lessons and highlighting challenges and opportunities for refinement. The culmination of this research provides a set of strategic recommendations for the implementation of Leagile supply chains, implications for practice, and a critical reflection on the study\u27s contributions to the field. The dissertation advocates for the adoption of the developed framework as a strategic blueprint for organizations aspiring to achieve a balance between efficiency and responsiveness in their supply chain operations, within the contexts of the current digital era and the pressing need for sustainability and resilience
Integrated Accessibility-Reliability Measurement For Evaluating Transit Equity Impacts
No full textABSTRACTThe concept of Equity (Fairness) in transportation is a very important subject that has gained a lot of attention in recent times for informing policy and decision making in the realm of transportation planning. A popular and well-regarded measure of transportation equity outcomes is accessibility. However, accessibility can be overestimated when travel time reliability (i.e., a measure of transit service adherence to schedule and/or consistency of service) is not considered. Travel time unreliability can have the broader effect of limiting passengers’ accessibility to desired destinations, with the degree of consequences varying by traveler locations and circumstances. This individual-level, temporospatial nature of travel time reliability has received limited attention in the transit accessibility- reliability literature. The objective of this dissertation work is to develop a framework that incorporates transit travel time reliability measure into an accessibility assessment to evaluate equity outcomes effectively and accurately from a behavioral perspective while paying attention to disadvantaged groups with limited travel options and using data that is widely available to transit operators and transportation practitioners. This framework enables a thorough evaluation of the multifaceted impacts of service reliability. By considering both spatial and social dimensions, it offers insights into the varying experiences of different traveler groups, informing policy and planning decisions accordingly. Furthermore, this dissertation takes the next step to explore how equity analysis methods can be advanced using an integrated measure of accessibility and reliability, comparing its impact on constrained and less constrained users. This study suggests that while accessibility is already recognized as an important measure of equity in transportation, incorporating reliability and the heterogenous nature of traveler alongside it provides a more nuanced and accurate understanding of the opportunities accessible to travelers
Understanding The Regions Around Supermassive Black Holes At The Centers Of Galaxies Using The Zowada Observatory
No full textActive Galactic Nuclei (AGN) occur in the centers of galaxies where a supermassive black hole (SMBH) is actively accreting material via an accretion disk. Reverberation mapping is a technique used to measure a size estimate of the accretion disk. Previous studies have found disk sizes ~3x bigger than expected, which may be due to optical interference from another region of the AGN known as the broad line region (BLR). The BLR produces optical emission lines and optical continuum emission similarly to and perhaps in excess to the accretion disk, which would interfere with the premise of accretion disk reverberation mapping. My work seeks to identify where the BLR affects our measurements and determine the dominant source of optical variability in AGN. My first study investigates this through a three-year observation campaign of AGN Mrk 876, where an emission line from the BLR directly interferes with our results. The next study looks at the AGN PG2130+099. Previous studies disagreed with each other as to the size of this object’s continuum emitting region. As lead P.I., I perform a follow-up study with multiple observatories to investigate this unusual AGN and determine what makes it unique. Finally, I analyze over 20 AGN light curves and comparing continuum emitting sizes versus observed luminosity. By combining our work with previous studies, we expand the range of masses and luminosities probed farther than ever before to determine and test to see if optical variability in AGN is influenced more from the BLR or the accretion disk
Beyond Ses: A Study Of Class, Status, Resources, And Health Under American Capitalism
No full textThis large cross-sectional study piloted a general framework for understanding the socioeconomic determinants of health in advanced capitalist societies. The framework represents a novel synthesis of existing concepts and measures that have been underexamined or undertheorized in academic psychology. The study began by identifying conceptual and practical problems with the study of socioeconomic status (SES) and examined these problems within the historical context of social inequality and its development. It then reviewed studies from various social science disciplines to understand social class, economic resources, and social statuses as distinct but related determinants of health. After recruiting a representative online sample of prime-working age Americans, this study tested many hypotheses and made a few significant contributions.
It was the first primary data analysis to relate E.O. Wright’s class typology to socioeconomic and health factors in a representative U.S. sample. The study also proposed a theory of multi-group social status and found evidence of construct validity for scales measuring status generally and in five arenas. There was preliminary support for the general framework connecting social class to general psychopathology and physical dysfunction via the pathways of general social status and economic resources. The study was limited by its design, sample idiosyncrasies, and inadequate sampling of the top and bottom of the class hierarchy.
Overall, the study calls attention to health inequalities associated with class and status hierarchies in America and the inadequacy of SES as a catch-all term and conceptual tool. Results provide evidence of construct validity for underexamined measures and point to areas for further inquiry at the intersection of psychology and social theory. A myriad of research directions were outlined, including refinement of neo-Marxian social class measures, development of the Hero Systems Status Scale, and use of the general framework in longitudinal studies that can address causal questions. In the end, this study may represent a call for a 21st century unified social science to grapple with the contradictory social relations of capitalist production and the evolved urge towards status hierarchies so that a new social order might be constructed to emancipate conscious life from needless humiliation, exploitation, and domination
Neonatal Respiratory Dysfunction And Language Outcome In Preterm Preschoolers
No full textThe aim of this study was to examine the contribution of respiratory dysfunction in the neonatal intensive care unit (NICU) on language outcome in preterm-born preschool-age children. Respiratory dysfunction was indexed by both a ranking based on type of respiratory complication (respiratory distress syndrome [RDS] or bronchopulmonary dysplasia [BPD]) and type of respiratory support and by length of respiratory support. Furthermore, the effect of sex on the relationship between respiratory dysfunction and language outcome was examined. Preterm children were assessed at 3-4 years of age. Respiratory diagnosis and support data were collected retrospectively from birth medical records. Analyses were performed first on a sample of 224 cases and then on a subsample of 211 cases following exclusion of cases with severe neurological complications. Language measures included global, expressive, receptive, semantic, syntactic, and morphological language scores from the Clinical Evaluation of Language Fundamentals – Preschool (CELF-P2) and oromotor functioning scores from the NEPSY-II. Separate analyses were conducted using respiratory dysfunction ranking, supplemental oxygen duration, and ventilation duration as predictors of interest and language measures as dependent variables. Covariates included socioeconomic status, sex, birth weight, standardized birth weight, and sum of non-respiratory perinatal complications. Results showed that longer requirement for oxygen was associated with lower total (p = .021) and receptive (p = .044) semantic language. This association remained significant after removing cases with neurological complications for total semantic language (p = .040) only. The interactions between sex and both respiratory dysfunction ranking (p = .046) and time on oxygen support (p = .045) on syntactic language were significant after removing cases with neurological complications. Specifically, females with higher degrees of respiratory dysfunction (p = .080) and longer time on oxygen support (p = .100) trended towards exhibiting significantly lower syntactic language scores, while these relationships were nonsignificant for males. Overall, the findings of the current study suggest that semantic and possibly syntactic (in females) language skills appear to be particularly vulnerable to the effects of increasing degrees of respiratory dysfunction in a preterm sample, even when excluding cases with neurological injury
Olanzapine-Induced Molecular Alterations In Skeletal Muscle Of Lean, Healthy Human Participants
No full textDiabetes affects approximately 37 million individuals in the United States, constituting approximately 11.3% of the population, primarily through Type 2 Diabetes (T2D) characterized by insulin resistance. Individuals with schizophrenia face an elevated risk of developing T2D, exacerbated by treatment with second-generation antipsychotics (SGAs). Understanding the metabolic disturbances induced by SGAs in schizophrenia necessitates investigations into their acute effects in healthy volunteers to delineate primary metabolic impacts from those secondary to chronic conditions like obesity or T2D. Studies on skeletal muscle have demonstrated that SGAs impair insulin signaling, glycogen content, and glucose transport. Olanzapine, a prominent SGA, is associated with significant metabolic liabilities, including insulin resistance independent of weight gain but underlying molecular mechanisms are still unknown. This study employs advanced proteomics methodologies to elucidate the molecular mechanisms by which olanzapine modulates insulin sensitivity in skeletal muscle. Proteomics profiling of lean, healthy skeletal muscle exposed to olanzapine identified substantial alterations in protein abundance and pathways pertinent to metabolism, glycosaminoglycan metabolism, muscular function, and diverse metabolic processes. Our analysis identified a total of 2127 proteins using TMT 29 plex. Among these, 23 proteins exhibited significant differences in abundance between pre and post Olanzapine treatment groups. Identified proteins are known to be involved in important pathways like muscle contraction, synthesis of pyrophosphates, inositol phosphate metabolism, diseases associated with glycosaminoglycan metabolism and glycosylation. These findings illuminate the molecular pathways through which olanzapine may instigate insulin resistance, irrespective of its effects on weight gain or adiposity. This research contributes novel insights into the proteomic disparities induced by olanzapine in skeletal muscle and provides a foundational basis for future investigations targeting the precise proteins implicated in insulin resistance pathways
Getting Away With Murder? The Problem Of Solving Homicides In Jamaica.
No full textAs Jamaica continues to welcome record breaking numbers of tourists annually, a well-known secret lingers beyond the shorelines: high homicides rates. As homicide rises, clearance rates remain abysmal. This dissertation examines the factors that affect clearance rates in Jamaica. Using previous literature which suggest that adequate police training and recruitment practices, adequate resources, decreased levels of corruption, police legitimacy and good leadership are the cornerstone of high homicide clearance rates, the dissertation assesses their influence in the Jamaican context. Employing the use of a qualitative approach that included semi-structured interviews, the dissertation found that, while there are definitional issues that adds a layer of complexity to the notion of clearance rates, inadequate homicide detective training is a major hindrance to the police agency’s ability to effect major changes to homicide clearance numbers. Additionally, the dissertation highlights the presence of other exogeneous factors including a culture of silence that is at the core of sustainedly low clearance rate
The Way Out: Human Cytomegalovirus Multi-Ome And Virion Egress
No full textHuman cytomegalovirus (HCMV) induces changes to most components of the host-cell environment during infection, including the proteome, secretome, and interactome. There are host-host, host-virus, and virus-virus interactions required for productive replication and release of virions: the infectious particles. Our previous systems-level analysis suggests that virion release is dependent on cellular regulators of exosome biogenesis and secretion: Rab 3 and 27. Here, we assess the complete spatial and temporal proteome of Rab proteins to identify their presence and potential roles in infected cells, virions, infected cell exosomes, and host-virus interactions. To further characterize the potential functions of the identified host-virus interactions, we developed a method for integrating multiple types of omic data: Multi-Dimensional Viromics. We used this method to i) create an atlas integrating temporal mRNA and protein expression, intravirion and cellular localization, interacting partners, and virus replication dependence for 129 HCMV proteins, ii) implement temporal normalization of protein abundances to highlight early-stage infection interactions, and iii) perform Gene Ontology and spatial/temporal proteomic analysis for 3400+ host-virus interacting proteins. Using this tool, we can now readily identify knowledge gaps and previously underappreciated potential host-virus interactions, and we provide a framework for integrated omic analyses for other biological models. We then used our multi-dimensional analysis method to characterize the novel interactions between Rab 3 and 27 with HCMV protein US27. Consistent with previous results, our bioinformatic analysis suggests that US27 can act as an activator of these secretory Rab proteins and is important for virion egress. This systems-level analysis tool can facilitate hypothesis-driven experimental design and help us better understand and appreciate the dynamics of host-virus biology. Collectively, this work contributes to our understanding of host and virus protein interactions required for HCMV infection and showcases novel experimental and bioinformatic systems to study host-virus interactions
Multiple daily injection insulin regimen is an effective, and more economical, alternative to continuous insulin infusion for type 1 diabetics
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Heller S, White D, Lee E, et al. A cluster randomised trial, cost-effectiveness analysis and psychosocial evaluation of insulin pump therapy compared with multiple injections during flexible intensive insulin therapy for type 1 diabetes: the REPOSE Trial. Health Technol Assess. 2017 Apr;21(20):1-278. https://doi.org/10.3310/hta21200
for a patient with type 1 diabetes