VictorJuiz/thesis huggingface dataset:
Outcomes of a Modified Pulpotomy Technique
Keywords: Pulpotomy
Formocresol
Outcomes
Modified

Background: Despite the high success rates reported with the use of a five minute application of formocresol it has been postulated that it may be applied for a lesser amount of time and still achieve equivalent results. Few studies have adequately addressed the effects of the medicament on permanent successors and exfoliation times. Furthermore, the effects of shorter application times on success rates have not been adequately reported. Objectives: To assess the clinical and radiographic outcomes of a one minute application of full strength Buckley’s formocresol with concurrent hemostasis using the medicated cotton pledget in human primary teeth. To evaluate the effect of this technique on their successors and to evaluate the exfoliation times in comparison to the contralateral non-pulpotomized tooth. Methods: Using a retrospective chart review, clinical and radiographic data were available for 557 primary molars in 320 patients. Descriptive statistics and regression analysis were used to assess outcomes. Results: 99.3% clinical and 89.8% radiographic success rates were obtained. Internal root resorption (4.85%) and pulp canal obliteration (1.97%) were the most frequently observed radiographic failures. Sixty-five and half percent exfoliated at the same time as their contra-lateral counterpart and 28.8% exfoliated earlier (p<0.001). There was no difference in the number of enamel defects of succedaneous teeth between treated and control teeth (p>0.05). Conclusions: Success rates for the modified technique are comparable to techniques that use the five-minute dilute or full strength solutions reported in the literature. The one minute technique had no clinical effect on exfoliation times or incidence of enamel defects on succedaneous teeth. The one minute full strength formocresol technique is an acceptable alternative to published traditional techniques.
Evaluation of a Caries Risk Assessment Model in an Adult Population
Keywords: dentistry
risk assessment

The purpose of this study was to evaluate a multifactorial caries risk assessment model by comparing the risk factor scores with caries increment. Secondary data analysis included a chart review of 434 dental patients in which basic caries risk scores, total risk score and caries increment were collected. ANOVA and logistic regression were conducted to assess the statistical significance of the difference between caries increments across categories of risk factors. Mean tooth caries increments of the risk groups were 0.20±0.8 (low), 1.13±1.59 (moderate), 2.09±2.63 (high), which were statistically significant (p<0.001). Past and present caries experience, carbohydrates, mucogingival bleeding index, and stimulated salivary flow showed statistically significant associations with caries increment (p<0.05) but the total risk score proved to be the most powerful predictor of future caries activity (p<0.001). The multifactorial etiology of caries necessitates the use of a risk assessment model that includes various factors that contribute to caries development.
Biodegradation of Resin-Dentin Interfaces Increases Bacterial Microleakage
Keywords: Biodegradation
Bacterial Microleakage
Resin-dentin interface

Bis-GMA-containing resin-composites undergo biodegradation by human saliva derived esterases, yielding Bis-hydroxy-propoxy-phenyl-propane (Bis-HPPP). The hypothesis of this study is that the exposure of dental restorations to saliva-like esterase activities accelerates marginal bacterial microleakage. Resin-composites (Scotchbond, Z250, 3M) bonded to human dentin were incubated in either buffer, or dual-esterase media (pseudocholinesterase/cholesterol-esterase; PCE-CE) with activity levels simulating that of human saliva, for up to 90 days. Incubation solutions were analyzed for resin degradation by-products using high-performance liquid-chromatography. Post-incubation, specimens were suspended in a chemostat-based biofilm fermentor cultivating Streptococcus mutans NG8 for 7 days. Bacterial microleakage was assessed by confocal laser scanning microscopy. Bis-HPPP production, as well as depth and spatial volume of bacterial cell penetration within the interface increased with incubation time. Biodegradation and bacterial microleakage were significantly higher for 30 and 90 day PCE-CE vs. buffer incubated groups (p<0.05). Conclusion: An overall decline in interfacial integrity was observed following exposure to human saliva-like esterases over time.
Investigation of Glass Fibre Reinforced Polymer Reinforcing Bars as Internal Reinforcement for Concrete Structures
Keywords: Reinforced Concrete
GFRP

A study of the existing data shows that two areas of GFRP bar research among others are in need of investigation, the first being behaviour of GFRP bars at cold temperatures and the second being the behaviour of large diameter GFRP rods. Based on the results of experimental work performed, cold temperatures were found to have minimal effect on the mechanical properties of the GFRP bars tested. In addition, through beam testing, large 32mm diameter GFRP bars were found to not fail prematurely due to interlaminar shear failure. By evaluating the mechanical and durability properties of GFRP bars and behaviour of GFRP RC, it can be concluded that GFRP appears to be an adequate alternative reinforcement for concrete structures. Because of high strength, low stiffness and elastic behaviour of GFRP bars, issues of significant importance for reinforced concrete are bond development, influence of shear on member behaviour and member deformability.
Nonlinear Finite Element Analysis of Static and Dynamic Tissue Indentation
Keywords: Tisuue Indentation
FEA Simulation

Detailed knowledge of tissue mechanical properties is widely required by medical applications, such as disease diagnostics, surgery operation, simulation, planning, and training. A new two degrees of freedom portable device, called Tissue Resonator Indenter Device (TRID), has been developed for measurement of regional viscoelastic properties of soft tissues at the Bio-instrument and Biomechanics Lab of the University of Toronto. As a device for clinical application, the accuracy and reliability of TRID is crucial. This thesis thus investigates the tissue samples’ mechanical properties through finite element analysis method after reviewing the experimental results of the same tissue samples using TRID. The accuracy of TRID is verified through comparing its experimental results with finite element simulation results of tissue mechanical properties. This thesis also investigates the reliability of TRID through experimental study of its indenter misalignment effect on the measurement results of tissue static stiffness, dynamic stiffness, and damping respectively.
Influenza Virus H5N1 Non-structural Protein 1 Alters Interferon-alpha/beta Signaling
Keywords: Influenza
Interferon

Type I interferons (IFNs) function as the first line of defense against viral infections by modulating numerous biological processes to establish an antiviral state and influencing the activation of various immune cells. During influenza A infection, the NS1 encoded by the virus genome disrupts many cellular processes to block type I IFN responses. We show that expression of H5N1 NS1 in HeLa cells reduces IFN-inducible activation of STAT proteins and its subsequent binding to DNA complexes. Subsequent analysis suggests NS1 blocks IFN signaling by inhibiting expression of type I IFN receptor subunit, IFNAR1, as well as up-regulating SOCS1 expression. Finally, we demonstrate that pretreatment of primary human lung tissue with IFN alfacon-1 inhibits H5N1 viral replication by up-regulating a number of interferon-stimulated genes. The data suggest that NS1 can directly interfere with Type I IFN signaling, and that pretreatment with IFN can inhibit H5N1 infection in primary human lung tissue.
VBR Video Streaming over Wireless Networks
Keywords: video streaming
wireless
networking
multimedia

Video streaming applications over wireless networks have turned out to be immensely popular recently. In this thesis, we first study the buffering schemes for the VBR video streaming in heterogeneous wireless networks. An analytical framework is presented to derive the expected number of jitters and average buffering delay. Through experimenting with a wide range of buffering schemes, we quantify the bene¯t of incorporating user location information in streaming over heterogeneous wireless networks. Second, we consider the delivery of scalable VBR video streams over wireless channels. We propose adaptive rate control algorithms to improve the combined system performance of video frame quality and playout smoothness based on the feedback information of wireless network estimation, buffer content and playback situation. The proposed adaptive rate control algorithms provide significantly improved streaming quality compared with the non-control policy.
Effect of Hyperbaric Oxygen on Non-Grafted and Grafted Calvarial Critical-sized Defects
Keywords: Hyperbaric Oxygen
Bone healing
Critical sized defect
Autogenous bone graft

Objectives: The purpose of this study was to evaluate whether the effects of hyperbaric oxygen (HBO) therapy could alter the critical size defect (CSD) diameter and to evaluate the effect of HBO on the repair of CSD in the presence and absence of a non-vascularized autogenous bone graft (ABG). Study Design: Twenty rabbits were divided in two groups of ten animals each. CSD were created in the parietal bones bilaterally. Defects were critical-sized, 15 mm on one side and supracritical-sized, 18 mm on the contralateral side. Group 1 received a 90-min HBO treatment sessions at 2.4 absolute atmospheric pressure (ATA) for 90 minutes per day for 20 days. Group 2 served as a normobaric roomair control (NBO). Additional ten animals were divided into 2 groups of 5 animals each. Bilateral CSD were created. ABG were allocated to one side of each calvarium. Group 1 received HBO treatments. Group 2 served as NBO. After sacrifice, data were collected including qualitative assessment, radiographic analysis, Micro CT bone analysis and histomorphometric analysis. ANOVA and paired sample t test were used for statistical analysis. Results: Both radiographic analysis and histomorphometric analysis demonstrated more new bone in the HBO CSD (p<.001). Micro CT analysis indicated a higher bone mineral content (BMC) in ABG CSD (p<.05). Histologically, complete bridging of the defect was observed in ABG defects. Histomorphometric analysis showed that HBO treatment increased new bone and marrow and reduced fibrous tissue in the defects (p<.01 for all). Conclusion: Bone regeneration was significantly greater in the HBO animals regardless of the defect size. HBO may have changed the accepted diameter of CSD to more than 18 mm. HBO enhances bony healing in non-grafted CSD.
Initial Examination of the English-language Dimensional Personality Symptom Item Pool
Keywords: personality measurement
developmental personality pathology
dimensional model of personality pathology
DIPSI

Dimensional models of personality pathology present a promising approach to the assessment of maladaptive personality in adults and children (eg. De Clercq, De Fruyt, & Widiger, 2009). In addition, recent findings show that some childhood maladaptive traits can be predictive of adulthood personality disorders (eg. Mervielde, De Clercq, De Fruyt, & Van Leeuwen, 2005). The Dimensional Personality Symptom Item Pool (DIPSI) is a questionnaire designed to measure maladaptive lower and higher order traits in children and adolescents. This study aims to examine the DIPSI’s scales and to replicate several previous findings of maladaptive trait patterns in children. The results indicate that the DIPSI’s lower and higher order trait scales are high in reliability and show many of the trait relationships suggested by previous literature. A successful outcome of this study serves as the first step towards establishing the DIPSI as a valid and useful measure of personality pathology in children.
Acoustic and Articulatory Changes Accompanying Different Speaking Instructions and Listening Situations
Keywords: clear speech
Lombard Effect
speech production in noise
speaking instructions
speech kinematics

The purpose of this study was to compare the effects on speech acoustics of a wide variety of speaking instructions that have been used across different studies on clear speech, and to investigate the acoustic and articulatory changes that occur in response to these instructions and in different talking environments. Five young adult females were recorded speaking under different instructions meant to elicit more intelligible speech, and measures of speaking rate, speaking F0 and intensity were found to distinguish instructions to speak "as if to someone with hearing loss" from instructions to speak "clearly" or "slowly", which produced different results from instructions to speak "loudly" or as if in noise. Preliminary acoustic and articulatory data are described for a sixth talker who spoke under a subset of these instructions, and in both a quiet and a noisy talking environment.
Autocatalytic Activation and Characterization of Staphylococcus aureus Cysteine Protease Staphopain A
Keywords: Protease
Staphylococcus
Virulence

Staphylococcus aureus secretes two cysteine proteases, Staphopain A (scpA) and Staphopain B (sspB). We hypothesized that ScpA will exhibit a distinct activation mechanism, and a different or complementary substrate specificity compared to SspB. A Cys>Ala active site substitution led to the accumulation of unprocessed 40-kDa proScpA, confirming that ScpA undergoes autocatalytic activation. A temporal analysis of ScpA expression revealed that activation was initiated by processing at Lys171 and Glu176, producing an intermediate that was rapidly converted to several isoforms of mature protease by processing after Thr202, Lys209, Thr214 and Asn216. Consistent with broad specificity, mature ScpA was sensitive to autocatalytic degradation. ScpA demonstrated activity towards elastin, fibrinogen and indicated evidence for binding to heparin. Elastinolytic activity was uniquely associated with strains belonging to CC30, and was correlated with ScpA expression. Therefore, although ScpA and SspB share both sequence and structural similarity, they exhibited very different substrate specificities and activation mechanisms.
Ending Impunity for International Corporate Crimes: A Review of Domestic Principles of Corporate Attribution and an Examination of their Application under International Law
Keywords: Corporate Liability
International Criminal Law
Attribution of Liability
International Law

Currently there are no mechanisms under international criminal law to hold corporations accountable for their role in the commission of human rights abuses. A primary problem with establishing corporate liability under international law, is that it is unclear how to attribute liability to corporations for international crimes. This paper examines the strengths and weaknesses of domestic principles of corporate attribution utilized in Canada, the United States, Britain and Australia. The domestic principles are then reconciled with current international law principles and enumerated crimes of international criminal law. It is argued that a flexible approach is optimal for the imposition of corporate liability under international law. While some of the domestic principles work better than others at first glance, ultimately all can and should be used at international law to end impunity for corporate crimes.
The Regulation of Juvenile Hormone in Dictyoptera: A Functional and Evolutionary Study of USP/RXR and Allatostatin
Keywords: juvenile hormone
allatostatin
Diploptera punctata
retinoid X receptor

The objective of this study was to clarify the regulation of production and signal transduction of juvenile hormone (JH) in insects by experimentally examining the function and evolution of a putative receptor (USP/RXR) and a neuropeptide inhibitor (FGLamide allatostatin). To examine the role of USP/RXR, the cDNA sequence of the receptor was obtained from the cockroach Diploptera punctata. Transcript levels during developmentally critical periods for JH sensitivity may suggest USP/RXR is JH responsive. Comparative sequence analysis of evolutionary rates in the Mecopterida support current hypotheses which suggest some gain in function along this lineage, although this acquisition may have occurred more gradually than previously assumed. To examine allatostatin evolution within insects, ancestral peptides inferred using maximum likelihood ancestral reconstruction methods were assayed for in vitro inhibition of JH production in two cockroach species. Shifts in peptide potency in some ancestral peptides reconstructed may be related to peptide copy number evolution.
Solid Molecular Dispersions of Itraconazole for Enhanced Dissolution and Controlled Drug Delivery
Keywords: solid molecular dispersions
solubility enhancement

The purpose of this study was to investigate the formation of solid molecular dispersions of Itraconazole (ITZ) in a number of glassy polymers including PVP, crospovidone, PVP-EC, HPMCAS and HPMCAS-PEO to enhance its dissolution and achieve release control. Polarizing light microscopy was found to be more sensitive than DSC and XRD for detecting crystallinity. PVP, PVP-EC & crospovidone generated loading levels of ~20%, substantially greater than that of HPMCAS and HPMCAS-PEO (5%). The loaded ITZ was stabilized though molecular interactions with the polymer and reduced molecular mobility in a glassy polymer matrix. Overall, immediate release was achieve d using PVP and crospovidone, enteric delivery provided by HPMCAS, and controlled release generated with EC and PEO. Among all polymers studied, only ITZ in PVP failed to generate sufficient stability in the presence of moisture. In general, solid molecular dispersion is a useful approach to improve the poor solubility and bioavailability of Itraconazole.
Lost Foam Casting of Periodic Cellular Materials with Aluminum and Magnesium Alloys
Keywords: Lost Foam
Truss
AZ91
A356
Lattice
cellular

This study investigates the possibility of fabricating periodic cellular materials (PCMs) via the lost foam casting (LFC) process using aluminum alloy A356 and magnesium alloy AZ91. This approach combines the structural efficiency of PCM architectures with the processing advantages of near-net-shape LFC. An initial feasibility study fabricated corrugated A356 panels. This was followed by a study of casting variables such as pattern design, vacuum assistance, and alloying additions in order to improve the fillability of the small cross-section struts. Finally, integrated pyramidal sandwich panels having different relative densities were subjected to artificial aging treatments and subsequently tested in uniaxial compression. The A356 PCMs experienced a continuous increase after yielding while the AZ91 PCMs exhibited strut fracture after peak strength. The results showed the compressive yield strengths of this study are comparable with those previously reported PCMs produced by different fabrication methods.
Risk of Acute Complications of Diabetes among People with Schizophrenia in Ontario
Keywords: Diabetes
Schizophrenia

Diabetes Mellitus (DM) is a complex, chronic disease, associated with potentially devastating complications. The DM-complication rate may be increased among people with schizophrenia. This study evaluated the relationship between schizophrenia and risk of preventable, acute DM-complications. Using administrative data, a retrospective study assessed acute DM complications (emergency department visits or hospitalization for hypo- or hyperglycemia, and hospital admissions for infections) among Ontario residents ages 18-50 with schizophrenia and newly diagnosed DM between 1995 and 2005, comparing people with and without pre-existing schizophrenia. People with schizophrenia had a 74% greater risk of requiring a hospital visit for hypo- or hyperglycemia (HR =1.74, 95% CI 1.42-2.12) compared to those without. The risk was similar when the outcome included infection (HR=1.62, 95% CI 1.39-1.89). Outcomes remained significant after adjustment for baseline characteristics. Understanding this relationship will direct future studies assessing barriers to care, and implementation of individualized approaches to care for this population.
Human Neutrophil Peptides: A Novel Agonist of Platelet Activation and Aggregation
Keywords: atherosclerosis
inflammation
alpha-defensins

INTRODUCTION: Platelets are involved in the inflammatory and thrombotic complications associated with atherosclerosis. Human neutrophil peptides (HNP), released from activated neutrophils, demonstrate inflammatory effects related to lesion development. HNP bind the low-density lipoprotein receptor (LR) family member LRP1 and LRP8 is the only member on platelets. HYPOTHESIS: HNP enhance platelet activation and aggregation through interactions with LRP8. METHODS: Platelet activation and aggregation in response to HNP were determined using flow cytometry and aggregometry. Activation was also examined in the presence of recombinant LRP8 and in LRP8 knockout platelets. RESULTS: HNP activate platelets as determined by P-selectin expression and the formation of microparticles. HNP sensitize platelets enhancing their aggregatory response to ADP. Lastly, LRP8 plays a role in HNP-induced platelet activation. CONCLUSIONS: With an improved understanding of the mechanism by which HNP induce platelet activation, we may be able to devise therapeutic strategies to treat patients with cardiovascular diseases.
Damage-tolerant Control System Design for Propulsion-controlled Aircraft
Keywords: aerospace engineering
control engineering
aircraft flight control

This thesis presents a damage-tolerant flight control system design for propulsion-controlled aircraft (PCA). PCA refers to an emergency piloting strategy that flight crews use throttle modulation only to achieve the attitude control of aircraft in case of conventional flight control system failures. PCA also refers to a conceptual or experimental aircraft that is installed with such automated thrust-only control system. When an aircraft undergoes structural damage to its airframe, lifting or control surfaces which cause conventional control system failures, PCA is adopted as an alternative control approach to stabilize the aircraft. However, the control of the damaged aircraft poses complications in stability recovering as unmodeled uncertainties and perturbed dynamics have significant impact on flight dynamics. Therefore, the PCA flight control system should have a high level of robustness against such model uncertainties, aerodynamics parameter deviations, and model perturbations. This thesis presents the study of robust PCA control system design using H infinity-based robust control method. The developed controllers are tested through both linear and nonlinear simulations. A comprehensive evaluation is performed for several different emergency scenarios. The results demonstrate the advantages of the newly-designed robust flight control architecture over the existing optimal controller in dealing with model deviations due to structural damage.