Evaluation of accuracy of implant impressions : a comparative analysis of the impression techniques, impression materials and the inter-implant span

Thesis (MSD) --Boston University, Henry M. Goldman School of Dental Medicine, 2009 (Department of Restorative Science and Biomaterial).Includes bibliographic references: leaves 88-94.Purpose: The aim of this study was to evaluate and compare the accuracy of implant casts made by differrent impression techniques and materials and to study the association between the inter-implant distance and the positional distortion of the implants. Method and material: A metal master model was duplicated from a clinical complete edentulous maxillary stone cast with four implant analogs placed in position of teeth # 3, 5, 11, 14 to serve as abutments for a short and a long FPDs. Using two impression materials (polyether and polyvinyl siloxane) and three impression techniques (Indirect, Direct and Direct Splinted), a total of sixty impressions were made of the master model. For the Direct Splint group, prefabricated acrylic resin bars were used to splint the impression copings. Coordinate Measuring Machine (FaroArm) with an accuracy of 0.025 mm was used to measure the relative position of implants on each cast on three axes ([delta]X,[delta]Y, and [delta]Z). The difference in global distortion inter-implant distances ([delta]R) on each cast and the master model was calculated. The Kruskal-Wallis test was selected for the analysis of the data followed by the Mann-Whitney (P [less than or equal to] 0.05 with confidence level of 95%). Results: The overall measured distortion of the inter-implant distance was [delta]R=0.11mm, [delta]X=0.05mm, [delta]Y=0.11mm, and [delta]Z=0.11mm. Irrespective of impression technique or material used, the longer inter-implant span’s distortion ([delta]R=0.14±0.04mm) was significantly more than the short span’s distortion ([delta]R=0.09±0.04mm) (P=0.05). Irrespective of impression material, the impression techniques produced comparable accuracy. Irrespective of impression techniques, polyether with mean distortion of ([delta]R=0.10±0.05mm) resulted in significantly better accuracy than poly vinyl siloxane with mean distortion of ([delta]R=0.13±0.04mm) (P=0.05).The results of this study demonstrated an interaction between the three tested factors (Impression technique, material and inter-implant distance).In some cases, the significance of the differences in accuracy was affected by this interaction. Conclusion: All three impression techniques and two impression materials studied showed some degree of distortion in transferring implant positions. The distance between two implants had a decisive influence on the accuracy of the transfer of the implant positions. The longer the inter-implant distance, more distortion of the impression occurred. Splinting impression copings results in statistically significant impression accuracy only if used in combination with polyether for impression of long inter-implant span. Some specific combinations of impression techniques and materials had a significant influence on the accuracy of the impression but considering the amount of distortion differences between the experimental groups (about 0.04mm or less), and the accuracy of the measuring device (0.025mm), the differences calculated for most variables may be too small for significant clinical impact

An Insect-Inspired Target Tracking Mechanism for Autonomous Vehicles

Target tracking is a complicated task from an engineering perspective, especially where targets are small and seen against complex natural environments. Due to the high demand for robust target tracking algorithms a great deal of research has focused on this area. However, most engineering solutions developed for this purpose are often unreliable in real world conditions or too computationally expensive to be used in real-time applications. While engineering methods try to solve the problem of target detection and tracking by using high resolution input images, fast processors, with typically computationally expensive methods, a quick glance at nature provides evidence that practical real world solutions for target tracking exist. Many animals track targets for predation, territorial or mating purposes and with millions of years of evolution behind them, it seems reasonable to assume that these solutions are highly efficient. For instance, despite their low resolution compound eyes and tiny brains, many flying insects have evolved superb abilities to track targets in visual clutter even in the presence of other distracting stimuli, such as swarms of prey and conspecifics. The accessibility of the dragonfly for stable electrophysiological recordings makes this insect an ideal and tractable model system for investigating the neuronal correlates for complex tasks such as target pursuit. Studies on dragonflies identified and characterized a set of neurons likely to mediate target detection and pursuit referred to as ‘small target motion detector’ (STMD) neurons. These neurons are selective for tiny targets, are velocity-tuned, contrast-sensitive and respond robustly to targets even against the motion of background. These neurons have shown several high-order properties which can contribute to the dragonfly’s ability to robustly pursue prey with over a 97% success rate. These include the recent electrophysiological observations of response ‘facilitation’ (a slow build-up of response to targets that move on long, continuous trajectories) and ‘selective attention’, a competitive mechanism that selects one target from alternatives. In this thesis, I adopted a bio-inspired approach to develop a solution for the problem of target tracking and pursuit. Directly inspired by recent physiological breakthroughs in understanding the insect brain, I developed a closed-loop target tracking system that uses an active saccadic gaze fixation strategy inspired by insect pursuit. First, I tested this model in virtual world simulations using MATLAB/Simulink. The results of these simulations show robust performance of this insect-inspired model, achieving high prey capture success even within complex background clutter, low contrast and high relative speed of pursued prey. Additionally, these results show that inclusion of facilitation not only substantially improves success for even short-duration pursuits, it also enhances the ability to ‘attend’ to one target in the presence of distracters. This inspect-inspired system has a relatively simple image processing strategy compared to state-of-the-art trackers developed recently for computer vision applications. Traditional machine vision approaches incorporate elaborations to handle challenges and non-idealities in the natural environments such as local flicker and illumination changes, and non-smooth and non-linear target trajectories. Therefore, the question arises as whether this insect inspired tracker can match their performance when given similar challenges? I investigated this question by testing both the efficacy and efficiency of this insect-inspired model in open-loop, using a widely-used set of videos recorded under natural conditions. I directly compared the performance of this model with several state-of-the-art engineering algorithms using the same hardware, software environment and stimuli. This insect-inspired model exhibits robust performance in tracking small moving targets even in very challenging natural scenarios, outperforming the best of the engineered approaches. Furthermore, it operates more efficiently compared to the other approaches, in some cases dramatically so. Computer vision literature traditionally test target tracking algorithms only in open-loop. However, one of the main purposes for developing these algorithms is implementation in real-time robotic applications. Therefore, it is still unclear how these algorithms might perform in closed-loop real-world applications where inclusion of sensors and actuators on a physical robot results in additional latency which can affect the stability of the feedback process. Additionally, studies show that animals interact with the target by changing eye or body movements, which then modulate the visual inputs underlying the detection and selection task (via closed-loop feedback). This active vision system may be a key to exploiting visual information by the simple insect brain for complex tasks such as target tracking. Therefore, I implemented this insect-inspired model along with insect active vision in a robotic platform. I tested this robotic implementation both in indoor and outdoor environments against different challenges which exist in real-world conditions such as vibration, illumination variation, and distracting stimuli. The experimental results show that the robotic implementation is capable of handling these challenges and robustly pursuing a target even in highly challenging scenarios.Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 201

Cognitive Rehabilitation Training in Improving Executive Function, Antisocial Behaviors, and Legal Problems in Children With Attention-Deficit/Hyperactivity Disorder

Background: Attention Deficit Disorder/Attention-Deficit/Hyperactivity Disorder (ADD/ADHD) is one of the most prevalent childhood diseases, and it may substantially influence social behaviors, legal issues, and disputes. The goal was to see how cognitive rehabilitation training affected executive functioning and impulsivity in children with ADHD in Tehran, District 5.Methods: A quasi-experimental design was used, with two groups (experimental and control) and a pretest-posttest. All students with ADHD disorder aged 7 to 12 years were included in the statistical population. The sample comprised 30 kids who were age-matched and randomly split into two groups. They were tested for two months in February and March 2021. Slow cognitive rehabilitation training was given to the experimental group. Both groups were given a pretest and a posttest. Information was gathered using the BRIEF (parent form) and Conners’ (parent form) questionnaires. MANCOVA was used to analyze the data, using the SPSS software v. 26, with a significance threshold of 0.05.Results: There was a significant difference in executive function variables (inhibition, attention transfer, emotional control, initiation, working memory, planning, material organization, and control) and reduced impulsivity (attention deficit , hyperactivity, opposition, and ADHD) (P≤0.001).Conclusion: Cognitive rehabilitation improves executive skills and impulsivity in children with ADHD aged 7-12 years. Cognitive rehabilitation training should be utilized with other educational approaches to rectify social behaviors, minimize conflict, and improve executive functions

The Influence of Positive Parenting Training on Improving Behavioral Function and Impulsivity in Children Suffering From Attention-Deficit/Hyperactivity Disorder

Background: Children with Attention-Deficit Hyperactivity Disorder (ADHD) have deficiencies in their executive functions and also impulsivity that can result in various social harms and criminal behaviors. Methods: The research had a two-group semi-experimental design (case/control) with a pre-/post-test. The statistical population consisted of all students’ mothers aged between 7 and 12 years old suffering from ADHD. The studied samples included 30 parents matched based on age and randomly divided into the case and control groups with 15 people in each group and were examined from 2nd February to March 2020. Positive parenting training was performed for the case group in eight sessions of 90 minutes by observing all protocols. Both groups experienced pre- and post-test. We applied the BRIEF (parent form) and Canners (parent form) questionnaires to collect data. Data were analyzed by MANCOVA using SPSS v. 26 software at a significance level of 0.05.Results: The studied samples were in the age range of 22-40 years (Mean±SD: case group: 32.93±6.04 years and control group: 34.13±5.47 years), 56% with education lower than diploma (0.60% and 46.7% for the case and control groups, respectively), and 44% had an official business (0.40% and 46.7%, respectively). Results showed significant differences in the variables of executive functions (inhibition, attention transfer, emotional control, initiation, working memory, planning, material organization, and control) and reducing impulsivity (cognitive problems-neglect, hyperactivity, opposition, and ADHD index) in the control and case groups (P<0.001). Conclusion: Positive parenting training significantly affects improving executive functions and impulsivity in children aged between 7 and 12 years old suffering from ADHD. Accordingly, it is achievable to help modify their social behaviors and also decrease the amount of conflict and legal problems among these children by providing a codified positive parenting training program in their educational programs

Using Rasch rating scale model to reassess the psychometric properties of the Persian version of the PedsQLTM 4.0 Generic Core Scales in school children

<p>Abstract</p> <p>Background</p> <p>Item response theory (IRT) is extensively used to develop adaptive instruments of health-related quality of life (HRQoL). However, each IRT model has its own function to estimate item and category parameters, and hence different results may be found using the same response categories with different IRT models. The present study used the Rasch rating scale model (RSM) to examine and reassess the psychometric properties of the Persian version of the PedsQL^TM4.0 Generic Core Scales.</p> <p>Methods</p> <p>The PedsQL^TM4.0 Generic Core Scales was completed by 938 Iranian school children and their parents. Convergent, discriminant and construct validity of the instrument were assessed by classical test theory (CTT). The RSM was applied to investigate person and item reliability, item statistics and ordering of response categories.</p> <p>Results</p> <p>The CTT method showed that the scaling success rate for convergent and discriminant validity were 100% in all domains with the exception of physical health in the child self-report. Moreover, confirmatory factor analysis supported a four-factor model similar to its original version. The RSM showed that 22 out of 23 items had acceptable infit and outfit statistics (<1.4, >0.6), person reliabilities were low, item reliabilities were high, and item difficulty ranged from -1.01 to 0.71 and -0.68 to 0.43 for child self-report and parent proxy-report, respectively. Also the RSM showed that successive response categories for all items were not located in the expected order.</p> <p>Conclusions</p> <p>This study revealed that, in all domains, the five response categories did not perform adequately. It is not known whether this problem is a function of the meaning of the response choices in the Persian language or an artifact of a mostly healthy population that did not use the full range of the response categories. The response categories should be evaluated in further validation studies, especially in large samples of chronically ill patients.</p

Association between fibrinogen receptor (Glycoprotein IIb) polymorphism and the risk of venous thromboembolism: a systematic review

Background: The fibrinogen receptor is an integrin on the platelet surface and is shaped from two types of glycoprotein (GP) subunits, GPIIb and GPIIIa. Membrane glycoprotein IIb/IIIa plays an important role in platelet function. The gene encoding the glycoprotein IIIa shows a common polymorphism, PLA2 that increases the binding of the receptor to fibrinogen and enhances the platelet aggregation. The clinical impact of PLA2 polymorphism has been studied in some diseases, but the definition of its exact role on venous thromboembolism complications has been challenging. The present systematic review aimed to clarify the association of PLA2 polymorphism and venous thromboembolism. Main text: In this study, Electronic databases including PubMed, Embase, Scopus, Web of Science, and Cochrane Library were searched. All the assessed studies focused on the relationship between PLA2 polymorphism and venous thromboembolism. Five studies were eligible for systematic review. One study revealed a significant correlation between PLA2 polymorphism and venous thromboembolism. PLA2 polymorphism was associated with deep vein thrombosis in one study and pulmonary thromboembolism in another one. Conclusion: The published data supported the hypothesis that having the PLA2 polymorphism of GPIIIa may be a risk factor for venous thromboembolism, but the association cannot be concluded; it needs more clinical investigation Keywords: Venous thromboembolism, Deep vein thrombosis, Pulmonary embolism, PLA2 polymorphis

Proposing a Model for Religious Tourism Development: Evidence from Iran

This study proposes a model for religious tourism as one of the most promising types of tourism worldwide, by focusing on the conditions of Iran as a potentially popular destination for religious tourism. The study relies on a mixed (qualitative and quantitative) method. The qualitative phase identifies the model dimensions and strategies. To do this, practitioners and experts were interviewed and the data collected were investigated through the thematic analysis method. This process revealed four main dimensions and 18 subsidiary strategies. In the quantitative phase, the dimensions and strategies identified were arranged in a questionnaire and through the survey method, were prioritised by experts in the Iranian tourism industry. The data analysis results, based on intuitionistic fuzzy AHP, revealed that the most important dimensions in religious tourism, as assessed by experts and practitioners in the Iranian tourism industry, were: ‘marketing strategies’, ‘HR training and development’, ‘reinforcing executive management structures’, and ‘implementing information technology.’ Finally, following a comparison of the results with those of another studies in this field, some executive and research-related suggestions are proposed

The antibacterial effect of methanolic fraction of Nepeta depauperataon against Pseudomonas aeruginosa isolates from burn wound infections

Background: In this study, the antibacterial effect of the methanolic fraction of Nepeta depauperata against 50 isolates of Pseudomonas aeruginosa from burn wound infections of patients who referred to Shahid Motahari hospital of Tehran in 2014 was evaluated.Materials and Methods: All bacterial isolates were confirmed by standard bacteriologic methods. Their resistant to common antibiotics were evaluated by disk diffusion method based on CLSI 2014. The Nepeta depauperata aerial parts were collected from Hormozgan Province and identified. Methanolic extract was prepared by maceration method using percolator apparatus and concentrated by rotary evaporator. The antibacterial activity of methanolic extract were determined by two methods; cup plate diffusion agar for determination the zone diameter of inhibition and microdilution broth for minimum inhibitory concentration (MIC) and further minimum bacteriocidal concentration (MBC). Statistical analysis was done by SPSS software version 20.Results: The percentage of resistance and susceptibility against nine different kinds of common antibiotic disk showed 83% resistance on average as evaluated by agar disk diffusion (Kirby–Bauer antibiotic test). Also, the mean of inhibition zone diameters has been measured in concentrations of 1000, 500, 250 mg/ml as follow: 12.58, 11.3 and 9.44 mm, respectively by cup plate and the amount of 87.93 and 104.78 mg/ml for MIC and MBC were determined, respectively, using the broth microdilution method. Statistic analysis was done with SPSS verssion19 software.Conclusion: According to the satisfying results of the antibacterial effect of the testing methanolic extract against clinical isolates of P. aeruginosa isolates further in vitro and in vivo studies are recommended

Health related quality of life of Iranian children with type 1 diabetes: reliability and validity of the Persian version of the PedsQL™ Generic Core Scales and Diabetes Module

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to measure health related quality of life (HRQOL) in Iranian children with type 1 diabetes and to test the psychometric properties of the Persian version of the PedsQL™ 4.0 Generic Core Scales and the PedsQL™ 3.0 Diabetes Module.</p> <p>Methods</p> <p>Participants were 94 children and adolescents diagnosed with type 1 diabetes for at least 3 months in Shiraz, southern Iran. Convergent, discriminant, and construct validity of the PedsQL™ 4.0 Generic Core Scales and the PedsQL™ 3.0 Diabetes Module were assessed. Moreover, internal consistency was checked by Cronbach's alpha coefficient.</p> <p>Results</p> <p>Cronbach's α for the PedsQL™ 4.0 Generic Core Scales and the PedsQL™ 3.0 Diabetes Module was greater than 0.80 both in the child self-report and parent proxy-report. Both generic and disease-specific versions of the PedsQL showed excellent convergent and acceptable discriminant validity except for 'diabetes symptoms' subscale in the child self-report of the disease-specific module. Moreover, Iranian children with diabetes, as compared with other countries, had lower HRQOL scores.</p> <p>Conclusions</p> <p>While this study showed that the Persian version of the PedsQL™ 4.0 Generic Core Scales has good psychometric properties in children with type 1 diabetes, the PedsQL™ 3.0 Diabetes Module needs some modifications to be used as a disease-specific quality of life (QOL) measure. Also, more support should be provided for the care of Iranian children with diabetes.</p