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The effect of composite bonding spot size and location on the performance of poly-ether-ether-ketone (PEEK) retainer wires
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Background: Poly-ether-ether-ketone(PEEK) has been introduced to many dental fields. Recently it was tested as a retainer wire‎ following orthodontic treatment. This study aimed to investigate the effect of changing the bonding spot size and location on the performance of PEEK retainer wires. Methods: A biomechanical study involving four three-dimensional finite element models was performed. The basic model was with a 0.8 mm cylindrical cross-section PEEK wire, bonded at the center of the lingual surface of the mandibular incisors with 4 mm in diameter composite spots. Two other models were designed with 3 mm and 5 mm composite sizes. The last model was created with the composite bonding spot of the canine away from the center of the crown, closer to the lateral incisor. The linear displacement of the teeth, strains of the periodontal ligament, and stresses in PEEK wire and composite were evaluated. The data was numerically produced with color coded display by the software. Selected values were tabulated and compared among models. Results: The amount of linear displacement and strain was very low. Stresses in the wire and composite were affected by the size and position of the composite bonding spot. The safe limits were identified at 235 MPa for PEEK and 100 MPa for composite. The basic model had a von Mises stress in the PEEK wire of 122.09 MPa, and a maximum principal stress in the composite of 99.779 MPa. Both stresses were within the safe limits, which means a lower risk of failure in PEEK and composite. All other models had stresses that exceeded the safe limit of the composite. The 3 mm composite model was the only one that developed stresses in the wire more than the safe limits of PEEK. Conclusions: Within the limitations of this study, bonding PEEK wires with 4 mm bonding spots to the clinical crown center provided the best mechanical performance of the wires and spots; otherwise, the mechanical properties of the wire and composite would be affected and, therefore, might affect the retention process. Keywords: Retention, PEEK, Finite element analysis

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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Medicine And Life
Effect of commercially pure titanium implant coated with calcium carbonate and nanohydroxyapatite mixture on osseointegration
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In this research, rabbit femurs were implanted with CP Ti screws coated with a combination of CaCO3 and nanohydroxyapatite, and the effect on osseointegration was assessed using histological and histomorphometric examination at 2 and 6 weeks. CaCO3 and nanohydroxyapatite were combined with the EPD to coat the surfaces of the CP Ti screws. The femurs of five male rabbits were implanted with coated and uncoated implant screws. Healing time was divided into two groups (2 and 6 weeks). After 2 and 6 weeks of implantation, the histological examination revealed an increase in the growth of bone cells for coated screws, and the histomorphometric analysis revealed an increase in the percentage of ne

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Publication Date
Thu Sep 22 2016
Journal Name
Applied Sciences
Analysis and Evaluation of Performance Gains and Tradeoffs for Massive MIMO Systems
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Publication Date
Wed Nov 04 2015
Journal Name
Eng. &tech. Journal
Photoconductivity and Performance of Mn2+ and Ce3+ Doped ZnS Quantum Dot Detectors
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Mn2+ and Ce3+ Doped ZnS nanocrystals were prepared by a simple microwave irradiation method under mild condition. The starting materials for the synthesis of Mn2+ and Ce3+ Doped ZnS P nanocrystals were zinc acetate as zinc source, thioacetamide as a sulfur source, manganese chloride and Cerium chloride as manganese and cerium sources respectively (R & M Chemical) and ethylene glycol as a solvent. All chemicals were analytical grade products and used without further purification. The nanocrystals of Mn2+ and Ce3+ Doped ZnS P with cubic structure were characterized by X-ray powder diffraction (XRD), the morphology of the film is seen by field effect scanning electron microscopy (FESEM). The composition of the samples is analyzed by EDS. The s

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Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Effect of the fungus Metarhizumanisopliae (Metchnikoff) Sorokin and actelic insecticide in the protection of bean seeds packaged in bag from infection by cowpea beetle
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this study was perform to defined the effect of fungus Metarhiziumanisopliae Sorokin with concentrations 5x101, 5x103 and 5x105 spore/ ml and Actelic insecticide with concentration 0.001% in in rate of germinate treated string bean seeds also study effect of packed bags in two different type: jute and polypropylene bags which treated with fungal suspension pervious mention and insecticide in rate infested the string bean seeds packed in it.Results of the study showed the following: Lower rate of weight loss of cowpea seeds appear in poly propylene bags 4.41, 5.95% after six months of treatment with 5x 105 spore/ ml and Actelic insecticide respectively compared with 15.08% to control treatment. The fungal concentrations and insecticide not

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Publication Date
Wed Mar 30 2022
Journal Name
Journal Of Economics And Administrative Sciences
Analyzing the impact of exchange rate fluctuations and inflation on the GDP in Iraq using the modern methodology of Cointegration for the period (1988-2020)
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     The research aims to analyze the impact of exchange rate fluctuations (EXM and EXN) and inflation (INF) on the gross domestic product (GDP) in Iraq for the period 1988-2020. The research is important by analyzing the magnitude of the macroeconomic and especially GDP effects of these variables, as well as the economic effects of exchange rates on economic activity. The results of the standard analysis using the ARDL model showed a long-term equilibrium relationship, according to the Bound Test methodology, from explanatory (independent) variables to the internal (dependent) variable, while the value of the error correction vector factor was negative and moral at a level less than (1%). The relationship bet

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Publication Date
Fri May 20 2005
Journal Name
Thesis
Extraction and Description of Urease Enzyme Produced from Staphylococcus saprophyticus and study of its effect on kidney and bladder of white mice
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Extraction and Description of Urease Enzyme Produced from Staphylococcus saprophyticus and study of its effect on kidney and bladder of white mice

Publication Date
Sun Sep 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
Measure the impact of the age structure of the population on the gross domestic product in Iraq
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   يهدف البحث إلى التعرف على The research aims to identify the effect ofاثر التركيب العمري للسكان على الناتج المحلي الإجمالي في العراق وتحديد الفئات العمرية من أطفال ومنتجين أي من هم في سن العمل والمسنين لأهمية ذلك لإغراض التخطيط الاقتصادي.إنeffectofeee age structure of the population on GDP in Iraq and determine the age groups of children and any of the producers wham are of working age and the elderly of the importance for the purposes of economic planning. نسبة الفئة العمرية Proportion of the age group (00- -4 4سنوات اقتربت من

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Publication Date
Tue Oct 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
The Impact of Exchange Rate Fluctuations on the Behavior of the Stock Markets in the Turkish Economy
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             A discussion about the repercussions of the exchange rate on the behavior of stock markets became one of the basic principles of financial economics. The Istanbul Stock Exchange , considered  one of the fastest financial markets growing in the region, driven by solid economic activity, for a diversified economy  which classified as one of the the fastest growing economies in the world. However, the aforementioned market witnessed sharp fluctuations in the past few months, coinciding with the continuous fluctuations in the exchange rate of the Turkish lira, posing a serious challenge to the economic and investment environment in a c

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Publication Date
Wed Jun 29 2022
Journal Name
Periodicals Of Engineering And Natural Sciences (pen)
The impact of the internet of things on information institutions from the perspective of library employees
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Publication Date
Fri Jul 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
The Impact Of Application Of Jit In The Banking Sector On The Quality Of Banking Service
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Abstract 

          The research the impact of the application of some of the production system tools in the specified time, which can be adapted in the service sectors (banking sector) over the improvement and increase the quality of banking services, and highlights the research problem in the low quality of banking services provided to customers because of the reliance on traditional banking systems in the provision of services Because of the lack keep pace with global developments in the banking industry, and the goal of research is to clarify the applicability of the production system in the time specified in the service sector and th

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