bluuebunny/crossref_metadata_2025 huggingface dataset:
Essays on the optimal choice of exchange rate regimes
Authors:   , Zhang Hongfang , Luca Alina C. , Jeon Bang Nam
Published: July 2021

The way a country manages its currency can affect its volume of trade, capital flows and income. A country, especially one with high degree of trade openness, needs to find the most suitable exchange rate arrangement to reduce the volatility of its currency value and output. This thesis examines the optimal choice of exchange rate arrangements from various aspects. The first essay examines whether or not the Northeast Asian economies, that is, China, Japan, Korea, and Taiwan can form a currency union, where a single currency and a uniform monetary policy are adopted, or an exchange rate union, where all the currencies are pegged to an internal or external currency or currency basket. It also attempts to find the optimal currency or currency basket for the four Asian economies if an exchange rate union is feasible. Structural VAR models with identification assumptions are applied to analyze the correlations of supply, exchange rate, monetary, and demand shocks. The paper finds that the shocks of these four economies are not symmetric, implying that the Northeast Asian economies are not ready yet to form a common currency union. However, it is found that these economies can form an exchange rate union with a major currency basket including the U.S. dollar, the Japanese yen and the Euro as currency anchor. The paper also examines the option of pegging to a basket of regional currencies, similar to the Asian Currency Unit (ACU). The second essay uses panel data on emerging and developing countries to study the interrelationships between balance-sheet currency mismatches and the choice of exchange rate regimes. The evidence shows that the lack of exchange rate flexibility reinforces currency mismatches and increases dollar liabilities, but the estimated economic effects are small. The third essay uses a three-country model to analyze the choice of the optimal weights of a currency basket for emerging market economies. This model assumes imperfect capital mobility and allows the domestic country to impose a reserve requirement on capital inflows. The optimal weights are derived by minimizing the loss from the volatility of output and trade. The result shows that the optimal weights are affected by variance of the cross exchange rate between the two major currencies, the covariance between inflations in the two large countries and the cross exchange rate, the relative weights assigned to trade and output, and price and exchange rate elasticities of trade, demand and supplies.
Distributed multi-phase distribution power flow
Authors:   , Kleinberg Michael R. , Miu Karen Nan
Published: July 2021

With the increasing presence of distributed intelligence throughout power distribution systems, the possibilities for distributed control and operation schemes are becoming progressively more attractive and feasible. Distributed operations will require tools to properly assess and predict the present and future status of the system in order to make proper control decisions. Multi-phase distribution power flow is a basic tool which calculates the operating state of the distribution system and is used to support all other applications. Therefore, this thesis will present a new method for calculating distribution power flow using physically remote distributed processors. The proposed power flow requires the distribution system to be partitioned with each partition distributed to a remote processor. Each processor then only requires detailed information about the portion of the network it will represent. Distributed analysis component models for multi-phase distribution systems have been developed to model the remaining network not explicitly retained in each partition. These models are embedded in a new distributed algorithm for multi-phase distribution power flow. Properties of the converged solution of this algorithm have been investigated and will be reported. A distributed processor test bed was designed to emulate the distribution of intelligent devices throughout power distribution networks and simulations were conducted to asses the proposed algorithm. Results have shown the proposed method will converge to the same solution as that of an un-partitioned traditional power flow validating the accuracy of the proposed models and algorithm.
An empirical investigation into alternative theories explaining taxpayer behavior
Authors:   , Flynn Kevin Eugene , Trewin Janet , Curatola Anthony Paul
Published: July 2021

This study furthers our understanding of taxpayer behavior by introducing two alternative theories that might provide better explanations of taxpayer behavior than prospect theory: the house money effect and the breakeven effect. Prospect theory posits that taxpayers in a refund situation act conservatively, while those in a tax due situation act aggressively. It is theorized in the house money effect that taxpayers in a refund situation act aggressively up to the point where the potential exists to eliminate the refund, at which point taxpayers become conservative. Conversely, it is theorized in the breakeven effect that taxpayers in a tax due situation act conservatively up to the point where the potential exists to eliminate the tax due amount, at which point taxpayers become aggressive. A secondary purpose of this study is to determine how a preliminarily determined current year tax position, also prior years' taxpaying experience, influence taxpayer behavior. A total of 415 graduate students from four regional universities in the Middle-Atlantic states completed a case study where they were asked whether they would take an ambiguous deduction given a 40 percent IRS disallowance rate and a risk of incurring IRS penalties and interest of $600. The subjects responded conservatively when provided with either a refund position or a tax due position. Therefore, these initial results do not support the house money effect, the breakeven effect, or prospect theory, but do support the idea that taxpayers are inherently conservative. However, when one of the assumptions, either the disallowance rate or the penalty and interest amount, was relaxed, subjects responded more aggressively. Subjects provided with a refund position responded in a manner consistent with the house money effect, while subjects provided with a tax due position responded in a manner consistent with the idea that a larger tax due position promoted more aggressive behavior. Further, when testing the refund position, current year versus prior year, an initial current year refund position more significantly promotes conservative behavior than an initial prior year refund position. When testing the tax due position, current year versus prior year, neither position has more influence over compliance behavior.
The role of self-appraisal of cognitive function in predicting psychosocial outcome
Authors:   , Kervick Robyn Beth , Williams J. Michael
Published: July 2021

Individuals who sustain a traumatic brain injury (TBI) can experience changes intheir physical, cognitive, and emotional status (Cifu, Kreutzer, Marwitz, Rosenthal, Englander, & High, 1996). Adjustment to these changes varies, with a number of interacting factors, including age, injury severity, psychological variables, and occupational status influencing outcome (Stratton & Gregory, 1994). Given the multitude of symptoms often experienced by the TBI survivor, it is perhaps surprising that individuals may not always be aware of such impairment. There is support that lack of awareness into disability may impede rehabilitation efforts and result in poor adjustment post-trauma (Prigatano, 1991). While a subset of individuals appears to minimize impairment, there is evidence to suggest that individuals with milder injuries may demonstrate exaggerated statements of impairment. However, no researcher has yet investigated the impact of symptom overreport on psychosocial outcome. The aim of the proposed study was to examine the extent to which self-appraisal of cognitive function was predictive of psychosocial outcome following TBI. It was hypothesized that accurate appraisal of cognition would predict better adjustment in terms of interpersonal relationships, independent living, and occupational status following TBI. Results from the investigation lent partial support for this hypothesis, although obtained effect sizes were small. Findings are discussed in the context of how they relate to previous research and future implications.
Thioether-oxime complexes of nickel(II) and copper(II)
Authors:   , Prushan Michael J. , Addison Anthony William
Published: July 2021

Nickel(II) and Copper(II) complexes of tetra-and pentadentatethioether-oxime ligands have been synthesized. An extraordinary range ofproperties are exhibited by the complexes. The tetradentate thioether-oximecomplexes of copper(II) form axial/equatorial dimeric complexes in the solidstate. These complexes exhibit weak ferromagnetic coupling betweenadjacent copper(II) ions. ESR spectra reveal that the dimer is broken insolution, and indeed the ESR spectra reveal tetragonal symmetry about thecopper(II) ions in the tetradentate thioether-oximes. The electrochemistry of these complexes supports the fact that oxime-containing ligands stabilizecopper(II). Nickel(II) forms a wide range of structures with the tetradentate ligands; the geometries vary from low-spin square planar to high-spin trinuclear complexes. The nickel(II) ions in trimeric complexes are disposed at the corners of an isosceles triangle and couple to each other through weak antiferromagnetic interactions. The electrochemistry of the trimeric nickel(II) complexes reveals that Ni(III) is attainable, due to the presence of anionic donors. Nickel(II) and Copper(II) form octahedral and square-pyramidal complexes with the pentadentate thioether-oxime ligands. The electrochemistry of the Ni(II) complexes reveals that most of the pentadentate ligands can stabilize both Ni(I) and Ni(III)
Numerical simulations of high Knudsen Number gas flows and microchannel electrokinetic liquid flows
Authors:   , Yan Fang , Farouk Bakhtier
Published: July 2021

Low pressure and microchannel gas flows are characterized by high Knudsen numbers. Liquid flows in microchannels are characterized by non-conventional driving potentials like electrokinetic forces. The main thrust of the dissertation is to investigate these two different kinds of flows in gases and liquids respectively. High Knudsen number (Kn) gas flows were characterized by 'rarified' or 'microscale' behavior. Because of significant non-continuum effect, traditional CFD techniques are often inaccurate for analyzing high Kn number gas flows. The direct simulation Monte Carlo (DSMC) method offers an alternative to traditional CFD which retains its validity in slip and transition low regimes. To validate the DSMC code, comparisons of simulation results with theoretical analysis and experimental data are made. The DSMC method was first applied to compute low pressure, high Kn flow fields in partially heated two dimensional channels. The effects of varying pressure, inlet flow and gas transport properties (Kn, Reynolds number, Re and the Prandtl number, Pr respectively) on the wall heat transfer (Nusselt number, Nu) were examined. The DSMC method was employed to explore mixing gas flows in two dimensional microchannels. Mixing of two gas streams (H₂ and O₂) was considered within a microchannel. The effect of the inlet-outlet pressure difference, the pressure ratio of the incoming streams and the accommodation coefficient of the solid wall on mixing length were all examined. Parallelization of a three-dimensional DSMC code was implemented using OpenMP procedure on a shared memory multi-processor computer. The parallel code was used to simulate 3D high Kn number Couette flow and the flow characteristics are found to be very different from their continuum counterparts. A mathematical model describing electrokinetically driven mass transport phenomena in microfabricated chip devices will also be presented. The model accounts for the principal physical phenomena affecting sample mass transport in microchip channels. Numerical simulations were performed to study the capillary electrophoresis flow in microchannels. Flow fields and species distribution are simulated for both the loading and the dispensing steps in a two dimensional cross channel device for species separation. The goal of these simulations is to identify the parameters providing optimal separation performance.
The effect of judicial instructions on jury consideration of defendant's refusal to testify
Authors:   , Zdrok Victoria A. , Bersoff Donald N.
Published: July 2021

This study investigated the effects of judicial instructions to disregard the defendant's failure to testify on juridical consideration of the defendant's silence. One hundred seventy nine actual jurors from the unused jury panels at the Philadelphia and Delaware courts watched one of the three versions of a two hour long condensed version of the actual trial. Trial versions differed in the strength of judicial instruction to disregard the defendant's silence. As predicted, instructing the jurors to disregard the defendant's silence resulted in greater conviction rate, consistent with the thought suppression and reactance literature. However, the conviction rate was not linearly related to the strength of the judicial instruction. It is hypothesized that other psychological factors, such as cognitive dissonance, may have contributed to this outcome. Jurors who rated defendant's silence as an important factor in their verdict outcome were more likely to find the defendant guilty. Results are discussed in light of the applicability of directed forgetting, thought suppression, belief perseverance and psychological reactance paradigms to the research on jury decision-making.
Investigating the role of nuclear receptors in HIV/HAART-associated dyslipidemic lipodystrophy
Authors:   , Berbaum Jennifer , Bentz Joseph Edward
Published: July 2021

The use of highly active antiretroviral therapy (HAART) to manage HIV infection is associated with the development of HIV/HAART-associated dyslipidemic lipodystrophy (HADL). HADL symptoms are comprised of metabolic dysfunctions resulting in hyperlipidemia, fat redistribution, and insulin resistance. The direct interaction of HIV drugs with nuclear receptors involved in metabolic pathways has been largely unexplored. HIV drugs were evaluated for effect on the activation of farsenoid X receptor (FXR), liver X receptor alpha (LXR[alpha]), retinoid X receptor alpha (RXR[alpha]), pregnane X receptor (PXR) and the peroxisome proliferator-activated receptor family (PPAR [alpha], [gamma], and [delta]). Our results indicate direct inhibition of PPAR[alpha] and PPAR[gamma] activation by protease inhibitors (PIs) in both coactivator recruitment and reporter gene assays. Gene chip analysis demonstrated that saquinavir and ritonavir reduced the expression level of PPAR[gamma] target genes in primary human hepatocytes. Partial recovery of mRNA levels of glucokinase (GK) and GLUT2 was achieved when hepatocytes were incubated in combination with the PPAR[gamma] agonist troglitazone. Decreased glucose sensing capabilities through PI-mediated inhibition of PPAR[gamma] activation may be a contributing factor in symptoms of HADL. PPAR[alpha] is the nuclear receptor responsible for regulating genes that control lipid homeostasis. Because of this role, PPAR[alpha] has become a target of interest for the development of drugs to treat diseases such as dyslipidemia, obesity and atherosclerosis. Assays currently employed to determine potency and efficacy of potential drug candidates typically utilize a truncated form of the native receptor, one which lacks the entire N-terminal region of the protein. We report that differences in PPAR[alpha] full length and ligand binding domain constructs result in differences in binding affinity for coactivator peptides, but have little effect on potency of agonists in both cell free and cell based nuclear receptor assays.
Performance of polypropylene geosynthetic filters under pressurized hydraulic flow conditions
Authors:   , Mitchell Blackwood Jade , Gurian Patrick L.
Published: July 2021

Fibers present favorable physical, hydraulic and specific surface area properties for use as a substrate in developing a novel media for the adsorption of heavy metals from drinking water. Specifically the high surface area of the fibers is able to achieve a significantly higher iron-oxide density than reported results for sand under similar coating conditions; the high porosity and high permeability can result in lower headloss in column treatment than traditional materials; and the chemical inertness of the surface can only achieve loosely attached, physically associated coatings making simple, physical regeneration a possibility. The coating procedures for iron-oxide coated sand from previously reported studies were considered as a model. Previous studies included abrasion tests to remove loosely attached iron-oxide after coating at unspecified or very high Reynolds numbers. This study was conducted to determine the ability of polypropylene fiber to retain a high iron-oxide coating under reasonable flow rates, typical of those used in water treatment, through column studies. In the column studies, the material was tested under two different packing schemes, and headloss, an important parameter to consider in choosing filter media for practical application, was also measured. Additional experiments were included to characterize the coated media, illustrate the removal effectiveness of a representative heavy metal (arsenic), and determine its ability to be regenerated. The polypropylene mat achieved an iron density of up to 99.8 mg Fe/g of material and retained 72% of this coating after being subjected to hydraulic flows several times the reasonable rate, while maintaining an acceptable headloss. However, even after washing at 100 bed volumes, the suspended iron concentration of the effluent water was consistently above the secondary MCL for iron in drinking water, 0.3 mg/L. While the samples showed a substantial reduction from the initial concentrations, the result, while promising is unreliable. Further investigation should include maximizing the coating conditions, minimizing iron loss in effluent water and evaluating the effective lifetime of the media.
Exploration of the fundamentals of matrix assisted laser desorption/ionization time-of-flight mass spectrometry
Authors:   , Erb William Joseph , Owens Kevin Glenn
Published: July 2021

This thesis focuses on the study of different tools used for preparing samples for MALDI TOFMS and the utilization of these tools to study different ionization processes operating in the MALDI experiment. The electrospray deposition technique was employed to study the effect of salt/analyte (S/A) ratio, a critical factor for the quantitation of synthetic polymer samples. The analysis was performed with four different matrices: DHB, CHCA, dithranol, and DCTB, with three different alkali ions: lithium, sodium, and potassium. The results obtained from titrating a PMMA 6800 sample with different alkalis in the presence of different matrices produced varying results, from an "ideal" titration curve using sodium with the DHB matrix to a "non-ideal" titration curve (i.e., increasing analyte signal up to a S/A value of approximately 1, followed by a decreasing analyte signal with further increases in salt) for sodium with the dithranol matrix. Utilization of a specially designed split probe in which the segregation of the PEG 1500 analyte and the lithium hyrdroxide cationization agent was complete, demonstrated the unequivocal proof of gas phase cationization. A dual electrospray deposition system was successfully developed in which two solutions are sprayed simultaneously, ensuring that the contents of the independently prepared samples are not mixed in the solution state. This device was used for the further study of both the gas phase cationization reactions of polymers and the counterion exchange reaction observed with inorganic complexes. Four matrices were used to analyze a ruthenium dimer complex in which the use of all matrices except DCTB led to dissociation of the non-covalent bonds of the dimer complexes. An analysis of hetero ligand ruthenium complexes with all matrices except DCTB demonstrated a counterion exchange reaction where the ClO4- or PF6- counterions were substituted by a matrix anion. Performing TOFMS instrument mass calibration using synthetic polymer calibrants with different molecular weight ranges uncovered visual and mathematical methods for evaluating the accuracy of the calibration function. Statistical analysis of systematic errors in the observed mass deviations enabled development of a correction method that yielded corrected mass values acceptable for use in accurate mass measurements.
The automated compilation of comprehensive hardware design search spaces of algorithmic-based implementations for FPGA design exploration
Authors:   , Balog Michael A. , Rosen Warren A.
Published: July 2021

Over the past few years FPGA hardware has become a logical choice for implementing cutting-edge signal processing applications. While there have been advances in FPGA technology, the common process of creating specialized hardware implementations for them is a manual one involving extensive design exploration. Design exploration is a process that requires a designer to look for designs that fit a set of performance characteristics such as size, throughput, or power depending on the application and it can be the most time consuming step when creating FPGA hardware. This process is a nontrivial task that requires extensive background knowledgeof both FPGA hardware and the application being implemented. While advances have been made in automating the process of design, there is still a gap between the application writers and hardware engineers that can be filled. This thesis presents a novel approach for automating the generation of hardware design search spaces that contain a comprehensive set of ways to implement signal processing algorithms with FPGAs. To accomplish this we generate a set of equivalent mathematical representations for an input equation via a novel declarative programming language that avoids a number of di±culties associated with the imperative languages used by previous approaches. We show that this equation space is bounded in terms of bracketing and ordering of mathematical operations, and that by changing the way an equation is written we can generate unique hardware instantiations (designs). The generated instantiations are mapped to heterogeneous computing architectures and written in a structural hardware descriptive language style to ensure that the intended instantiation will behave as predicted in hardware. A software system was created based on this approach that generates an equation space for varying numbers of summed multiplications and converts each representation into a comprehensive hardware design search space that can be analyzed for performance characteristics such as size, throughput, latency, and power.
Templated growth and characterization of carbon nanotubes for nanofluidic applications
Authors:   , Mattia Davide , Gogotsi Yury
Published: July 2021

Nanofluidics deals with the static and dynamic behavior of fluids at the nanoscale. Fundamental nanofluidic studies are focused on understanding whether continuum fluid mechanics equations hold at the nanoscale and whether there is a threshold dimension below which they no longer apply. Device fabrication focuses on developing integrated systems capable of handling attoliter (10-18 liter) or less of fluid for applications ranging from single molecule detection in biology to microchip cooling. Interest in nanofluidic increased with more widespread availability of carbon nanotubes (CNT), which appeared to have the ideal characteristics for this kind of studies. Prior to the development and commercial application of nanotube-based devices, the mechanisms of nanofluidic phenomena, liquid interaction and transport within the internal cavity of carbon nanotubes has to be better understood. The proposed PhD research is dedicated to the development of carbon nanotubes with geometry, wall structure and chemistry, and properties optimized for fluidic applications, as wells as understanding the liquid-carbon interactions. The results obtained will be applied to control the flow of fluids through nanotubes. These nanotubes will be used as building blocks of nanofluidic devices.
Texture evolution in processing of polystyrene-clay nanocomposites
Authors:   , Steinmetz David Richard , Li Christopher Y. , Kalidindi Surya
Published: July 2021

Polymers are used in a wide variety of applications, including but not limited to construction plastics materials, electronics and communications, surface coatings, packaging, and automobiles. They are used extensively because they are lightweight, relatively inexpensive, and have desirable properties. A prominent area of interest lies in the enhancement of material properties in polymer systems. The primary method of property enhancement has been the addition of a secondary phase, usually on the nanoscale such as layered silicate clays or carbon nanotubes. The purpose of this study was to develop an innovative technique to study the microstructure of polymer-clay nanocomposites. An X-ray diffraction technique was developed which allows non-destructive evaluation of orientation distribution of clay plates in polystyrene with two different morphologies: intercalated and phase separated. X-ray diraction, thermogravimetric analysis, dynamic mechanical analysis, and light absorption were used to characterize the composites. Observation of texture evolution as a function of strain in polystyrene montmorillonite composites was reported, as was the dierence in texture evolution between intercalated and phase separated samples. The dierence between texture evolution was also reported using two dierent diraction peaks from the same mixed sample, the intercalated peak and the phase separated peak.
Attention to change
Authors:   , Lease-Spellmeyer Jessica F. , Williams J. Michael
Published: July 2021

Neglect, a dramatic manifestation of attention, is a primary source of strokerelated long-term disability (Katz, Hartman-Maeir, Ting, & Soroker, 1999). Subtle attention deficits (extinction) may recover more slowly than overt symptoms (neglect). (Heir, Mondlock, & Caplan, 1983) While often not captured by traditional bedside tests, subtle deficits have real-world implications. To guide rehabilitation efforts, it is clinically relevant to examine attention in a 6-month post-lesion population. The visual attention tasks in this study were a simple detection task and a change detection task. A novel component of this study was vigilance, sustaining attention over extended periods of time. The frontal lobes are associated with vigilance (e.g. Manly & Robertson, 1997), and the frontal-parietal cortex mediates spatial attention (e.g. Beck, Rees, Frith, & Lavie, 2001). This study examined the role of the frontal-parietal network in detecting change at spatial locations over time. Nine frontal-lesioned, seven parietal-lesioned, and twenty-nine non-lesioned individuals were administered the Detection and Monitoring Tasks. The Detection Task required participants to report whether the letter 'T' appeared, and if so, in which hemispace. The Monitoring Task involved bilateral stimuli presentation of two blinking red 'T's. The participants were asked to report whether either letter changed to green, and if so, in which hemispace. The temporal component of both tasks was for the stimuli to appear (Detect Task) or change (Monitor Task) over the time intervals of 200, 800, 1400, or 2000 msec. Detection Task: No participants showed an accuracy performance difference over time or hemispace. Contralesional accuracy performance was worse than Ipsilesional performance for Parietals, but not Frontals. Contralesional RT performance, relative to Ipsilesional, was worse for all patients. Parietals performed significantly worse (accuracy and RT) than Controls. Monitoring Task: No participants showed a performance difference over time. Surprisingly, all participants showed a hemispheric difference. Accuracy performance for right hemispace was significantly worse than left hemispace. This left-hemispace advantage may explain why patients did not demonstrate worse Contralesional accuracy performance, relative to Ipsilesional, despite slower Contralesional RT performance. Parietals performed worse (accuracy and RT) than Controls. A trend suggested better accuracy performance for Frontals relative to Parietals.
Power flow computation using field programmable gate arrays
Authors:   , Vachranukunkiet Petya , Nagvajara Prawat , Johnson Jeremy Russell
Published: July 2021

Power flow computation is ubiquitous in the operation and planning of power systems. Traditional power flow computation is performed using commodity general purpose processors that are commonly found in today's personal computers. These general purpose processors however, are not necessarily designed to provide optimal performance for power flow computation. The goal of these general purpose processors is to provide good performance across a wide range of problems, but not necessarily for all problems. Recently, field programmable gate arrays (FPGA) have been identified as having the capability to compete with these high frequency processors for floating point throughput despite operating at a much lower clock speed. This research presents the methodology used to design an implementation of an FPGA based accelerator for power flow computation that provides increased performance over the standard general purpose processor solution. The design follows a fine-grained study of the sparse LU decomposition of several benchmark power system matrices. Performance results for this hardware design indicate an order of magnitude improvement in solve time compared to a state of the art sparse LU solver package for personal computers. The limitations of fine-grained parallelism are explored and additional performance through higher-level parallelism is also presented.
Finding groups of graphs in databases
Authors:   , Peabody Mitchell A. , Regli William C. , Shokoufandeh Ali
Published: July 2021

Presented with a database of solid models, the task is to group the solid models together by similarity. This similarity can be defined in a number of ways, including topological or feature interaction. It turns out that both of these similarity metrics can be represented by undirected, simple graphs, and the problem can be abtracted to grouping graphs by similarity. To do this, a metric that captures the differences in graphs is needed. Unfortunately, known metrics are NP-Hard to calculate. In this thesis, I further expand on an approximate similarity metric known as [lambda]-distance and propose a way to handle cospectral graphs. In addition, I use a well established clustering algorithm to graphs these graphs into clusters. I use techniques from information theory to measure the quality of results on controlled datasets of random graphs. This work is applied to the problem of grouping a set of solid models.
Occupational stress, social problem solving, and burnout among mental health professionals in HIV/AIDS care
Authors:   , Huey Solam Tsang , Nezu Christine M.
Published: July 2021

The burnout syndrome is a multidimensional process consisting of emotional exhaustion, depersonalization, and reduced personal achievement affecting health and service workers. Mental health professionals have particular vulnerabilities to occupational stress and burnout due to the nature of their work, and those who work with HIV/AIDS individuals are believed to face additional demands. The current study had three objectives: 1) To examine the relationships between occupational stress, social problem solving ability, and burnout among mental health professionals who work with HIV/AIDS individuals; 2) To predict the dimensions of burnout from occupational stress and social problem solving ability, and; 3) To examine whether social problem solving ability moderates the effects of occupational stress on burnout. Following Dillman's Tailored Design Method, a mail survey measuring demographic and professional information, negative life stress, occupational stress, social problem solving ability, and burnout was sent to a heterogeneous group of 200 mental health professionals working with HIV/AIDS individuals. The total return rate was 63% (n = 126), with 39% (n = 78) meeting study inclusion criteria. Results indicated that occupational stress significantly correlated with emotional exhaustion and depersonalization, while social problem solving ability significantly correlated with all three dimensions of burnout. Occupational stress predicted emotional exhaustion and depersonalization even after controlling for demographic, professional, and negative life stress factors. Social problem solving ability predicted only personal accomplishment above and beyond demographic, professional, negative life stress, and occupational stress factors. Lastly, social problem solving ability did not moderate the relationship between occupational stress and burnout, suggesting that more effective problem solving may not buffer against burnout under higher levels of occupational stress. However, there may be some benefits to using an impulsive response style in decreasing emotional exhaustion. Results suggest that evaluating mental health professionals' social problem solving ability in addition to occupational stress may allow for better identification of those who may be at risk of burnout. Implications of findings, study limitations, and suggestions for future research are discussed.
Theoretical and experimental approaches to control blood vessel growth into tissue engineered scaffolds
Authors:   , Jabbarzadeh Ehsan , Abrams Cameron F. , Laurencin Cato T.
Published: July 2021

The field of tissue engineering s to regenerate natural tissues and create new tissues using combinations of living cells, biomaterials and signaling molecules. One of the important requirements for biomaterials is that they allow for development of healthy, internal capillary networks. The objective of this project was to explore the underlying mechanisms that control vascular growth into porous biomaterials through a co-operation between experimentation and mathematical modeling. We developed a a discrete probabilistic mathematical model of cell migration and vascular growth into porous biomaterials. Some of the highlight results of this study included the following: (i) transience in chemoattractant secretion profiles determined the effectiveness of cell motility and cell-to-cell signaling, (ii) tuning the pore surface reactivity to angiogenic factors offered a possible mechanism to hasten the speed of cell migration and tissue ingrowth, and (iii) optimal release durations of an angiogenic growth factor induced deeper vascular growth into the scaffold. The experimental part of this project aimed at exploring the variables that influence the extent of vascular growth in 3D porous poly(1actide-co-glycolide) (PLAGA) sintered microsphere scaffolds. In addition, we designed a combined gene-therapy/cell- transplantation strategy to induce vascular ingrowth. Some of the highlight results of this work were: (i) PLAGA scaffolds supported the growth and biological functions of endothelial cells and adipose derived stromal cells (ADSCs), (ii) vascular endothelial growth factor (VEGF) transfected ADSCs secreted biologically active VEGF on scaffolds, (iii) in-vivo implantation of PLAGA scaffolds containing transfected ADSCs and endothelial cells showed a significantly improved vascular ingrowth.
A path analysis of the role of symptom severity and health care and educational resources in the psychosocial functioning of adults with Tourette Syndrome
Authors:   , Keefer Amy J. , Nezu Christine M.
Published: July 2021

Ninety-five individuals with Tourette Syndrome (TS) registered with the Pennsylvania-Tourette Syndrome Association (mean age=37.0) participated in a study to determine if the severity of TS symptoms and the goodness-of-fit of health care and educational resources received in childhood have an impact on a variety of psychosocial variables through adulthood. Participants completed questionnaires containing measures of TS symptom severity in childhood, the goodness-of-fit of resources received in childhood, the quality of parental relationships in childhood, the quality of peer relationships in adolescence, the level of daily stress in adulthood, the level of social support satisfaction in adulthood, the level of employment satisfaction in adulthood, the amount of drug and alcohol use in adulthood, and the level of psychological distress in adulthood. Three pathways were added to the hypothesized model to reach an acceptable fit ·([chi]²=13.521, p=.562). Fourteen of the model's 20 pathways were found to be significant. The goodness-of-fit of resources had an indirect effect on psychological distress in adulthood through the quality of peer relationships in adolescence and daily stress level in adulthood. TS symptom severity had both a direct effect on level of psychological distress in adulthood and an indirect effect on the level of psychological distress through the quality of parental relationship in childhood and daily stress levels in adulthood. TS symptom severity in childhood and social support satisfaction in adulthood had direct effects on drug and alcohol use in adulthood. Social support satisfaction in adulthood significantly predicted employment satisfaction in adulthood.
Sensitivity, non-equilibrium thermodynamic and control analyses of insulin metabolic signaling pathways
Authors:   , Liu Ensheng , Yuan Jian-Min
Published: July 2021

The transportation of glucose, the primary energy source of all eukaryotic cells, from the bloodstream to the cells is catalyzed by a family of glucose transporters (GLUTs), among which GLUT4 is insulin stimulated and regulated. To study the insulinstimulated glucose transport, we analyze the hybrid metabolic and signaling pathway models constructed by Sedaghat, et al. by applying multiple strategies based on dynamic sensitivity analysis, concentration control analysis, non-equilibrium thermodynamics, and nonlinear dynamics. In dynamic sensitivity analysis, we have calculated the time-dependent sensitivities of the concentration of the membrane GLUT4 with respect to all the reaction parameters (reaction rate constants and initial concentrations of the effectors). The roles of feedbacks are investigated by using dynamic sensitivities. In addition, the integrated sensitivities of the membrane GLUT4 have been used to rank the accumulated influence of each reaction parameter on the membrane GLUT4. Results are consistent with experimental facts and predictions of drug targets in the literature. Furthermore, a strategy is developed using dynamic concentration and sensitivity analyses to control certain outputs of the insulin pathways. The objective is to enhance the accumulated action of the membrane GLUT4 for a fixed amount of insulin input. In the application of non-equilibrium thermodynamics, we calculate the fluxes, chemical affinities, and energy dissipated rates associated with each of the reaction steps of the pathways. The flux and chemical affinity associated with the GLUT4 translocation to the plasma membrane show clear sign of backflow, after the insulin application is suddenly switched off. This backflow results in the decrease in the concentration of membrane GLUT4, thus the reduction of glucose transport. Stimulated by these results, we have carried out a study of insulin dosage delivery aimed at enhancing the duration of the high concentration period of membrane GLUT4, that is, increasing insulin efficiency using various insulin input functions. Negative feedback and/or delay often cause oscillatory behaviors of a network system. This phenomenon reveals itself in the present insulin model as well. Nonlinear dynamical analysis and power spectra have been applied to the study of the complex oscillations associated with effectors concentrations.
Numerical simulations of droplet trajectories from an electrostatic rotary-bell atomizer
Authors:   , Colbert Steven Anthony , Cairncross Richard Allan
Published: July 2021

Electrostatic spray coating (E-spray) is widely used for coating conductive substrates. The combination of a high-velocity focusing air, an imposed electric field and charged droplets, leads to higher transfer efficiency than that of conventional spray coating. In this thesis, a mathematical model of trajectories of droplets generated by a rotary-bell electrostatic atomizer is described which enables predictions of coating deposition rate patterns. A dilute spray assumption (i.e., no particle-particle interactions) allows modeling single droplet trajectories resulting from a balance of electrostatic force, drag and inertia. Atomization of liquid droplets is not modeled explicitly - instead an empirical correlation is used for the mean droplet size while individual droplet sizes and starting locations are determined using random distributions. The electrostatic field and droplet trajectories are strongly coupled and calculated iteratively with successive substitution and relaxation. Parametric studies on how bell voltage, bell rotation speed, and focusing air affect spray pattern, mass transfer efficiency, and droplet trajectories are presented. Simulated spray patterns are compared to those of physical experiments. For the parameter values considered in this thesis, most of the predicted sprays are hollow cones with negligible deposition near the center axis, deposition of a heavy ring surrounding the center and a tapering of thickness towards the outer edge of the substrate. In contrast, most of the experimental results display non-axisymmetric deposition patterns in the form of two lobes of coating. In addition, the experimental deposition patterns are relatively insensitive to any of the three primary parameters (i.e. bell rotation speed, bell voltage, or focusing air intensity). These results are not obtained with the simulations, which show a moderate trend between both uniformity and transfer efficiency, both of which are favored by high bell rotations speeds and lower voltages.
Reliability and validity of the progress questionnaire
Authors:   , Chapman Jason E. , Williams J. Michael
Published: July 2021

Patient- focused research is a methodology that involves the regular measurement of patient progress in treatment and the provision of feedback to clinicians to allow modification of interventions to maximize outcomes. A critical component of patient focused research endeavors is the availability of psychometrically sound assessment questionnaires, and one such measure is the Outcome Questionnaire (OQ-45.2). This investigation was comprised of three studies. Study 1 examined the factor structure and internal consistency of the Progress Questionnaire (PQ), an adaptation of the OQ-45.2, in 278 patients seeking psychotherapy and/or medication management services at a large, urban outpatient mental health clinic. Study 2 examined the factor structure and internal consistency of the OQ-45.2 in a sample of 450 patients receiving outpatient psychotherapy in numerous locations. Study 3 examined the temporal stability of the factor structure of the OQ-45.2. The PQ and OQ-45.2 were found to possess desirable estimates of internal consistency, similar to those previously reported for the OQ-45.2. The theoretically derived three factor structure of the OQ-45.2 was submitted to Confirmatory Factor Analysis (CFA) and found to be implausible for the PQ and the OQ-45.2. The studies next turned to exploratory procedures so as to investigate the empirical factor structures of the questionnaires. Results of a Principle Components Analysis (PCA) with Promax rotation revealed that the PQ was comprised of ten correlated factors accounting for 60% of the observed variance. Similarly, the OQ-45.2 was comprised of nine correlated factors accounting for 62% of the observed variance. The sample size in Study 2 permitted validation of this factor structure through CFA. The nine factor model provided significantly improved fit to the three factor model previously tested but was still implausible. Study 3 found that the ninefactor structure obtained with baseline data was not stable when imposed on a sample of data from the fourth assessment. The results suggest that the PQ is statistically less effective than the OQ-45.2, and further use of the modified version is not recommended. Possible explanations for the poor fit of the factor structures are offered, and guidelines are provided for future psychometric studies examining the OQ-45.2.
Effects of initial microbial density on disinfection efficiency and explanatory mechanisms
Authors:   , Kaymak Baris , Haas Charles Nathan
Published: July 2021

Numerous water disinfection studies have reported deviations from the Chick-Watson Law, which was used to develop the CT tables provided by the USEPA's SWTR. Some of the modifications of the Chick-Watson Law incorporate explicit dependence on initial microbial density. In this study a series of inactivation experiments were conducted with a gram-negative (E. coli) and a gram-positive bacterium (B. subtilis) and a protozoan (G. muris) under various growth stages to investigate cell density effects on inactivation. Cell density dependent inactivation was observed only during inactivation of continuous and batch cultures of E. coli at stationary growth phase and during inactivation of G. muris cysts. There was a statistically significant decrease in disinfection efficiency as the initial microbial density decreased. Inactivation of E. coli at exponential growth phase, vegetative cells of B. subtilis at exponential growth phase, and B. subtilis spores were independent of cell density. Statistically significant effects of growth phase and culture growth technique on inactivation efficiency were observed in E. coli experiments. Exponentially growing cells of E. coli were more sensitive to monochloramine than stationary phase cells. Batch cultures of E. coli were more resistant to monochloramine than continuous cultures of E. coli. Similarly, spores of B. subtilis were more resistant than the vegetative cells at exponential growth phase. The inactivation data of B. subtilis spores and G. muris cysts obtained in this study showed that B. subtilis spores can be used as a conservative surrogate to verify the removal efficiency of G. muris as they would overestimate CT requirement (over an order of magnitude) during the ozonation process. Comparison of survival data of B. subtilis spores from this study with survival data of C. parvum in the literature showed that B. subtilis spores were less resistant at higher ozone CT. However, the relation between survivals of C. parvum oocysts and B. subtilis spores can be expressed precisely using multiple linear regression. Using inactivation data of B. subtilis spores, an approximately 2-log reduction of C. parvum by ozonation was verified. B. subtilis spores could be used as a simple and inexpensive surrogate for on-site disinfection process performance.