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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

The impact of dental implant length on failure rates : a systematic review and meta-analysis

Abdel-Halim, Maha, Issa, Dalia January 2021 (has links)
Purpose  To evaluate the impact of implant length on failure rates between short (<10 mm) and long (≥10 mm) dental implants.   Materials and methods A search was undertaken in three electronic databases, complemented by manual search of some journals. Implant failure was the outcome evaluated, with the estimate of relative effect expressed in risk ratio (RR). Heterogeneity among studies was evaluated by I2statistic. Inverse variance method was used for random- or fixed-effects models. Quality assessment of the studies was performed, and a funnel plot was drawn. A meta-regression was performed in order to verify how the RR was associated with the follow-up time.   Results The reviews included 353 publications. Altogether, there were 25,490 short implants and 159,435 long implants. Pairwise meta-analysis showed that short implants had a higher risk of failure than long implants (RR 2.437, p<0.001). The meta-regression observed that the follow-up time did not have any effect of the RR of failure between short and long implants. A sensitivity analysis plotting together only the studies with follow-up up until 7 years, resulted in an estimated increase of 0.6 in RR for every additional month of follow-up.   Conclusion Short implants showed (< 10 mm) a 2.5 times higher risk of failure than long implants (≥ 10 mm). Implant failure is multifactorial and the implant length is only one of the many factors contributing to the loss of implant. A good treatment plan and the patient’s general health should be taken into account when planning for an implant treatment.       Keywords: dental implant, failure, implant length, systematic review, meta-analysis
412

Wool Production, Systematic review of Life Cycle Assessment studies / Ullproduktion, Systematisk granskning av livscykelanalysstudier

Devaux, Caroline Alexandra January 2019 (has links)
Wool is often being marketed as sustainable. However, when looking at LCA studies, results can be significantly different from one study to another and wool sometimes shows higher impacts than other fabrics. Based on a comprehensive literature review, this thesis aims at understanding the key environmental impacts of wool production and assessing the influence of main methodological choices on wool LCA results. In particular, the choice of the scope, allocation method and further considerations on water consumption and land use indicators have a great significance on the results of the studies. In order to provide with a fair representation of wool environmental impacts, the whole life-cycle should be taken into account, and methodological choices, such as the scope definition and allocation methods are to be clearly stated. The current tools that are the most widely used in the textile industry to rank fibres according to their sustainability performance are not suitable for wool due to unresolved methodological issues. Indeed, the impact categories that are taken into account in those tools are disadvantageous for wool compared to other alternative fibres, especially regarding water consumption and land use. This thesis also explores the construction of a single score based on the eco-costs of environmental impacts as a more suitable option to build a representative tool.
413

What Teachers Want To Know: A Systematic Review Of Action Research Theses Related To K-8 Mathematics And Science

Steele, Bridget 01 January 2006 (has links)
The research conducted was a systemic review of 88 action research masters theses from a teacher enhancement program for K-8 mathematics and science at the University of Central Florida and the teachers that performed the studies. The purpose of this study is to synthesize existing research results of a collection of master's theses from a teacher enhancement program for K-8 mathematics and science teachers in order to arrive at meaningful conclusions regarding teachers' research interests and classroom practices. Also, the study will help teacher educators who deliver the teacher enhancement program to improve the effectiveness of the program. A summary sheet was filled out for each thesis and teacher, and then entered into a spreadsheet that was later analyzed for reoccurring themes in the data. The results showed themes in topics of action research studies, questions in action research studies, and results of action research studies. There were no trends in characteristics of teachers performing the action research studies.
414

The Placenta as a Predictor for Future Cardiovascular Health Following Placenta-Mediated Diseases

Mery, Erika 19 December 2022 (has links)
Introduction: The placenta is essential for fetal development and pregnancy prolongation. Its dysfunction can lead to short and long-term health consequences for mother and child. A subset of diseases resulting from placental dysfunction have been collectively termed placental-mediated diseases (PMD) - which includes the common and serious hypertensive disorder of pregnancy preeclampsia (PE), among others. PMDs are independent risk factors for maternal cardiovascular disease (CVD) in later life. This thesis presents a multi-pronged body of work, which includes: 1) A systematic review, aimed at summarizing the current state of knowledge on the risk for future maternal CVD after PMDs; 2) A cohort study, aimed at assessing the utility of placenta pathology examination at delivery to identify women at high lifetime risk for CVD following PE; and 3) An assessment of an immunohistochemistry screening panel for 3 placenta protein markers of interest, aimed at determining if these markers can accurately identify women deemed to be at high-risk for future CVD following a PE pregnancy. Methods: 1) We searched 4 databases for observational studies evaluating clinical and biochemical markers of CVD risk and/or a subsequent calculated risk score based on these parameters in women with a history of PMD. We excluded interventional studies and studies measuring these outcomes during or prior to pregnancy. 2) A cohort study was established across two clinical sites (Kingston, Ottawa), in which patients with PE (N=85) underwent cardiovascular risk assessments at 6-months postpartum. The placentas from these pregnancies also underwent detailed placenta histopathology examination to determine the presence, absence, and severity of 35 distinct placental lesions. The associations between distinct placental lesions and estimated lifetime cardiovascular risk were evaluated by odds ratios (OR) and receiver operator curve analysis (ROC). 3) Immunohistochemistry (IHC) analysis was performed on placental samples from a subset of the previously described cohort (N=41; Ottawa site only). Protein expression for FLT-1, ENG, and CD68 was quantified. Using a multivariate logistic regression model, the association between placenta protein expression, with and without clinical and placenta pathology findings, and cardiovascular risk was assessed. Results: 1) The search yielded 11,039 articles of which 104 met our inclusion criteria. All PMD types demonstrated evidence of increased CVD risk markers at varying timepoints postpartum. At least one study per PMD type had non-optimal measures of systolic blood pressure, BMI, and total cholesterol. 2) In the analysis of placenta pathology lesions within the cohort of individuals with PE, lesions of maternal vascular malperfusion (MVM) were found to be associated with elevated life-time risk for maternal CVD at 6 months postpartum (OR: 3.10[1.20-7.92]). We also found that adding these lesions to a logistic regression model improved the predictive accuracy for elevated maternal lifetime CVD risk (AUC: 73.0, sensitivity: 78.4%, specificity: 51.6%). 3) Individually, no significant differences were found in FLT-1, ENG, and CD68 expression between the individuals deemed to be at high and low-risk for lifetime CVD. Although, when added to a model that included placenta pathology lesions and clinical data the predictive accuracy for elevated maternal lifetime CVD risk increased (AUC: 1.0, sensitivity: 100%, specificity: 100%). Conclusions: In conclusion, this thesis provides further evidence of the utility of assessing placenta features in the prediction of future maternal CVD. This is evidenced by the association between PMDs, placental pathology, and placental protein biomarkers with elevated risk profiles for lifetime CVD. Thus, specific placental phenotypes of PMDs may be at increased risk for CVD. The use of placental data should be further explored as a triage strategy to identify these high-priority of women following delivery.
415

Three Essays on the Determinants of Radicalization: A Case of North-Western Pakistan

Nawaz, Fahim 16 December 2022 (has links)
Radicalization is as a formidable challenge for several nations. While radicalization continues to flare across the world, empirical evidence and consensus regarding its determinants remain scarce. This cumulative dissertation aims to contribute to understanding the determinants of radicalization based on three research papers. The first paper undertakes a systematic review of the existing scientific literature on radicalization. The second paper empirically tests the predictive power of the most plausible factors identified in the systematic review. The third paper empirically investigates the existence of non-linearities in the relationship between radicalization and socioeconomic factors.:1. Introduction 2. Understanding the Determinants of Radicalization: A Systematic Review 3. An Empirical Assessment of the Determinants of Radicalization: Evidence from North-Western Pakistan 4. Socioeconomic Factors and Radicalization in Pakistan: A Non-Linear Exploration 5. References
416

Appetite Hormones Following Roux-en-Y Gastric Bypass: What is the Magnitude of Change with Time?

Simoneau, Mylène 18 January 2023 (has links)
Background. Roux-en-Y gastric bypass (RYGB) is an effective treatment for obesity, where gut peptides such as ghrelin, glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) play an instrumental role in reduced appetite after RYGB. This systematic review and meta-analysis aimed to establish the magnitude of change of ghrelin, GLP-1, PYY and appetite sensation following RYGB. Methods. A systematic search was conducted in Medline Ovid, Embase, Scopus, and Cochrane Central Register of Controlled Trials up until March 2021. Two independent reviewers screened articles for studies that evaluated ghrelin, GLP-1, PYY or appetite sensation via visual analogue scales (VAS) before and after RYGB in adults. Risk of bias was assessed with the quality assessment tool for before-after studies with no control group from the National Heart, Lung and Blood Institute (NHLBI). A multilevel model with random effects for study and follow-up time points nested in study was fit to the data. The model included kilocalorie consumption as a covariate and time points as moderators. Results. Among the 2,559 articles identified, 47 met the inclusion criteria, among which k=19 evaluated ghrelin, k=40 GLP-1, k=22 PYY and k=8 appetite sensation via VAS. Our results indicate that fasting ghrelin levels are decreased 2 weeks post-RYGB (p = .005) but do not differ from baseline from 6 weeks to 1-year post-RYGB. Postprandial ghrelin levels at 6 months and 1-year post-RYGB were not different from pre-surgical values (p = .51). Fasting GLP-1 levels were not different from pre-surgical levels up to 2 years post-RYGB. Postprandial levels of GLP-1 increased significantly from 1 week (p < .001) to 2 years post-RYGB (p < .01) compared to before surgery. Compared to pre-RYGB levels, fasting PYY increased at 6 months (p = .034) and 1 year (p = .0299) post-surgery and postprandial levels were increased up to 1 year (p < .01). Heterogeneity was significant in most analyses. Insufficient data on appetite sensation was available to be meta-analyzed. Conclusion. Our analyses illustrate the magnitude of change of ghrelin, GLP-1 and PYY before and after RYGB surgery. Importantly, between study heterogeneity within the current literature warrants more standardized protocols and studies with longer follow-up periods for better comprehension of changes in gut peptides following RYGB surgery.
417

Informing the design of an age of blood crossover randomized controlled trial in patients with Myelodysplastic syndromes to study change in quality of life as a response to RBC transfusion

Sholapur, Naushin Saba 11 1900 (has links)
Patients with myelodysplastic syndromes (MDS) frequently receive red blood cell (RBC) transfusions to alleviate symptoms of anemia and improve health-related quality of life (HR-QoL). Patients can sometimes continue to feel unwell after transfusion and the age of the transfused RBCs could contribute to this observation. Three pilot studies were conducted to inform the design of a randomized crossover trial to determine if fresh blood to MDS patients could improve HR-QoL post-transfusion. A systematic review was performed to inform the background and rationale for the trial. The results showed a dearth of literature addressing the research question. Only two clinical trials have been conducted to date where fatigue and HR-QoL were the primary outcomes of interest. Although results of the trials were negative, several limitations and generalizability issues warrant additional research in this area. Crossover designs necessitate patients have a stable prognosis while being observed; hence, a chart review of adult MDS patients was conducted to assess clinical stability using the following criteria: interval of days between transfusions; pre-transfusion Hb; number of hospital admissions; and severe infections. Results indicated that the majority of patients who had received greater than 3 transfusions within the 6-month observation period had stable disease and were appropriate for a crossover trial. The criteria defining stability will be useful for identifying eligible patients. Finally, an applied qualitative study in adult MDS patients in Hamilton was conducted to inform the selection of an appropriate outcome measure (i.e. HR- QoL tool). Short semi-structured interviews were conducted with participants to elicit information about anemia related symptoms and changes in well-being in response to transfusion. The results of the study support clinical observations that suggest patients do not immediately recover post-transfusion. Findings indicate that an appropriate HR-QoL tool should be short, be disease specific, and have a short recall period. Currently, the Quality of Life-E tool, validated in patients with MDS, fits most of these criteria. In conclusion, data from the systematic review and the two pilot studies suggest that it may be feasible to conduct an age of blood crossover trial in MDS patients where the primary outcome of interest is HR-QoL. / Thesis / Master of Science (MSc)
418

MANAGING PREOPERATIVE ANXIETY IN CHILDREN UNDERGOING SURGERY

Chow, Cheryl H.T. January 2017 (has links)
Objectives: 1) To examine the effectiveness of Audiovisual (AV) interventions at reducing preoperative anxiety (PA) and its associated outcomes in children undergoing surgery; 2) To assess the psychometric properties of a new scale, the Children’s Perioperative Multidimensional Anxiety Scale (CPMAS); 3) To examine the feasibility and acceptability of a novel tablet-based intervention, Story-Telling Medicine (STM), for reducing children’s PA; 4) To examine the relation between temperament and PA in the surgical context. Methods: A systematic review of studies where the primary outcome was children’s PA was conducted (Study 1). A study of the reliability and validity of the CPMAS were assessed at preoperative assessment (T1), on the day of surgery (T2), and 1 month postoperatively (T3) was also undertaken (Study 2). The feasibility and acceptability of STM were then examined and compared its effect to Usual Care (UC) (Study 3). Finally, children’s temperament was examined using the Colorado Childhood Temperament Inventory at T1 along with the CPMAS assessed at T1 and T2 (Study 4). Results: Fourteen of the 18 studies led to reductions in children’s PA (Study 1). The CPMAS demonstrated good internal consistency, stability and convergent validity across all visits (Study 2). The participant recruitment and study procedures were shown to be feasible and children in the STM group demonstrated greater reductions in CPMAS compared to the UC group (Study 3). Shyness predicted lower PA at T1, while sociability predicted higher PA at T1 and T2 (Study 4). Conclusions: AV interventions appear useful but full-scale RCTs of these treatments are required to pinpoint those that are most effective. The CPMAS is a promising tool for evaluating children’s PA and preliminary evidence suggests that STM is a feasible intervention for reducing children's PA. Finally, our findings highlight the importance of considering individual differences in predicting anxiety in the surgical setting. / Thesis / Doctor of Philosophy (PhD) / Preoperative anxiety affects up to 5 million children in North America annually and is associated with many adverse psychological, behavioural, and health effects. These problems not only produce significant distress for children and families, but can have immediate and long-term effects on a child’s mental health and development. Current methods to reduce preoperative anxiety in children (e.g., medications and psychological preparation programs) are limited by their expense and/or time-intensive nature. In an attempt to reduce children’s preoperative anxiety and its associated negative outcomes, this work examined the usefulness of audiovisual interventions in reducing children’s preoperative anxiety, sought to develop a new instrument to measure children’s preoperative anxiety, tested a new tablet-based application to reduce children’s preoperative anxiety, and examined the relation between children’s temperament and preoperative anxiety. The goal is to improve the surgical experience for children and families, and to reduce psychological and physical problems in children undergoing surgery.
419

Clinical Practice Guidelines for the Management of Neonatal Abstinence Syndrome: A Systematic Review and Evaluation

Figeys, Christine 05 December 2023 (has links)
Neonatal abstinence syndrome (NAS) refers to the withdrawal symptoms experienced when an infant has been exposed to certain substances (e.g., opioids) in-utero, resulting in health challenges for infants. Previous studies have reported substantial variations in the clinical management of NAS, suggesting that some infants may not be receiving optimal care. High-quality clinical practice guidelines are crucial to support optimal patient outcomes and standardize care. In response, I conducted a systematic review and quality appraisal of available NAS guidelines and recommendations using the AGREE-II and AGREE-REX tools. I also developed and piloted a tool to measure family-centred care in guidelines. Most guidelines received low-quality appraisal scores on the AGREE-II and the AGREE-REX appraisals (16/20 and 10/20, respectively) and have conflicting pharmacological recommendations. Findings will improve clinicians’ awareness of the variation in the quality of guidelines and assist them to make care decisions that are from the best available evidence and family-centred.
420

Systemic Quinolones and Risk of Adverse Reactions: Integrating Evidence from Clinical and Epidemiological Evidence Streams

Taher, Mohamed Kadry 31 May 2021 (has links)
Quinolones are a group of antibiotics that have gained significant popularity on a global scale since the end of the last century. This popularity was predominantly based on their proven potency, broad coverage against a wide range of bacteria, in addition to possessing a favorable pharmacologic profile. Whereas quinolone-associated adverse reactions are generally tolerable and self-limiting, some reactions have generated heightened concerns due to their serious nature, which have resulted in label changes or even market withdrawal in some instances. This thesis investigates the association between quinolone antibiotics and two adverse reactions of an acute and serious nature: acute liver failure and retinal detachment. Each adverse reaction is investigated through integrating evidence from three studies utilizing different designs based on data from different sources, with each source offering a unique perspective on this issue. The first study type (chapter 2 for acute liver failure ‘ALF’ and Chapter 5 for retinal detachment ‘RD’) analyzes spontaneous reports submitted to the US Food & Drug Administration (FDA) adverse event reporting system database. Chapters 3 and 6 systematically identified all relevant (published and unpublished) clinical trials for occurrences of ALF and RD, respectively, among trial participants. Finally, chapters 4 (ALF) and 7 (RD) involved case-control analysis of a major US database of electronic health records for nearly 70 million inpatients admitted to more than 500 hospitals between 2000 and 2016. The FAERS analysis revealed a positive ALF signal with ciprofloxacin and a marginal signal for RD with moxifloxacin. Examination of the evidence from clinical trials revealed only two cases of ALF, one associated with gemifloxacin and one with moxifloxacin. No cases of RD were reported in any of the identified clinical trials. Primary analyses of the Health Facts® data revealed no overall association between quinolones and the risk of ALF or RD. However, elevated risk was identified in some subgroups, including African Americans (ALF, RD), Caucasians (ALF), women (ALF, RD), men (ALF), those ≤60 years of age (ALF) or 56-70 years of age (RD), and those with no or few comorbidities (ALF). Evidence from analyses of data from spontaneous reports and clinical trials provided some evidence for an elevated risk of ALF or RD following the systemic administration of quinolone antibiotics. Some evidence of elevated risk was also identified in the case-control analyses of inpatient EHR records. Findings from our six epidemiologic studies are in line with current advisories by FDA and Health Canada.

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