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In Vitro Evaluation of Shear Bond Strength of Sapphire Brackets after Dental Bleaching
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Background: The present study was conducted to evaluate the effects of different bleaching methods on the shear bond strength of orthodontic Sapphire brackets bonded to human premolars teeth using light cured composite resin and to determine the predominant site of bond failure. Materials and Methods: Thirty freshly extracted human premolars were selected and randomly divided into three groups (10 per group). These groups are: control (unbleached) group, hydrogen peroxide group (HP) 37.5% ; which is the in- office bleaching method group, carbamide peroxide group (CP) 16%; which is the at- home bleaching method group. After bleaching process was performed, all the teeth stored in distilled water in a sealed container at room temperature for 24 hours before bonding was initiated, then orthodontic brackets were bonded with a light cure composite resin, stored in distilled water at room temperature for another 24 hours before debonding then the brackets de-bonded and tested for shear bond strength using an Instron universal testing machine. For adhesive remnant index (ARI) the enamel surface and bracket base of each tooth were inspected under magnifying lens (20X) of a stereomicroscope. Results and Conclusions: Non-statistically significant differences of shear bond strengths were found between the control group and the bleached groups, the dental bleaching in both methods did not affect the SBS of Sapphire brackets. The mode of failure was mostly between the adhesive and the enamel and the bond failure between the bracket base and the adhesive were also observed. Keywords: Shear bond strength, tooth bleaching agents, orthodontic brackets, dental bonding.

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Publication Date
Sun Aug 01 2021
Journal Name
Nano Biomedicine And Engineering
In-vivo and In-vitro Anti-Acinetobacter Baumannii Activity of Citrate-Capped Silver Nanoparticles
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Silver nanoparticles (AgNPs) are of potential interest because of their effective antibacterial and antiviral activities. Capping agents are used for exhibiting a better antibacterial activity than uncapped Ag NPs. There are very few reports that have shown the usage of AgNPs for in-vivo antibacterial therapy. Citrate-capped silver nanoparticles were synthesized chemically by citrate reduction method; the size of Cit-AgNPs was determined by an atomic force microscope (AFM) and was between 15-90 nm. Acinetobacter baumannii (A. baumannii) isolates were the only sensitive species to Cit-AgNPs. MICs and MBC of Cit-AgNPs were determined by using A. baumannii. The results showed an additive effect of Cit-AgNPs. Four mice groups were infected with

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Publication Date
Sun Mar 01 2020
Journal Name
Iraqi Journal Of Physics
Studying the Impact Strength of Layered Denture Base Resin
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This paper displays the effect of uncoated and coated chopped carbon fibers with alumina Al2O3 or Tri calcium phosphate (TCP) on the impact strength of acrylic poly methyl methacrylate (PMMA) denture base resin. To improve bonding between carbon fibers and coating materials powders, the surface of carbon fibers has been treated with Para amino benzoic acid (C9H10N2O3) and poly vinyl alcohol (PVA) was also used. The morphology of the coating layers has been examined by field emission scanning electron microscope (FE-SEM). From the results, PMMA reinforced with uncoated chopped carbon fiber has high impact strength value but still have bad aesthetic.  Samples prepared b

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Publication Date
Fri May 01 2015
Journal Name
Journal Of Engineering
Strength Improvement of Clay Soil by Using Stone Powder
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Soil stabilization with stone powder is a good solution for the construction of subgrade for road way and railway lines, especially under the platforms and mostly in transition zones between embankments and rigid structures, where the mechanical properties of supporting soils are very influential. Stone powder often has a unique composition which justifies the need for research to study the feasibility of using this stone powder type for ground improvement applications. This paper presents results from a comprehensive laboratory study carried out to investigate the feasibility of using stone powder for improvement of engineering properties of clays.

The stone powder contains bassanite (CaSO4. ½ H

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Publication Date
Sat Jan 01 2022
Journal Name
Iop Conference Series: Earth And Environmental Science
Residual post fire strength of non-prismatic perforated beams
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Abstract<p>The main aim of this study is to assess the performance and residual strength of post-fire non-prismatic reinforced concrete beams (NPRC) with and without openings. To do this, nine beams were cast and divided into three major groupings. These groups were classified based on the degrees of heating exposure temperature chosen (ambient, 400, and 700°C), with each group containing three non-prismatic beams (solid, 8 trapezoidal openings, and 8 circular openings). Experimentally, given the same beam geometry, increasing burning temperature caused degradation in NPRC beams, which was reflected in increased mid-span deflection throughout the fire exposure period and also residual deflectio</p> ... Show More
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Publication Date
Sat Feb 27 2021
Journal Name
Journal Of Engineering
Shaft Resistance of Long (Flexible) Piles Considering Strength Degradation
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Soil-structure frictional resistance is an important parameter in the design of many foundation systems. The soil-structure interface area is responsible for load transferring from the structure to the surrounding soil. The mobilized shaft resistance of axially loaded, long slender pile embedded in dense, dry sand is experimentally and numerically analyzed when subjected to pullout force. Experimental setup including an instrumented model pile while the finite element method is used as a numerical analysis tool. The hypoplasticity model is used to model the soil adjacent to and surrounding the pile by using ABAQUS FEA (6.17.1). The soil-structure interface behavior depends on many factors, but mainly on the interface soi

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Publication Date
Sun Feb 10 2019
Journal Name
Journal Of The College Of Education For Women
The Egyptian-Ethiopian Relations after the Change
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Egypt and Ethiopia have connected in a strong relation as there are historical facts that
deepen these relations, one of these is Egypt's cooperation in establishing the first economic
and financial banking system in Ethiopia.
Beside the religious relation between The Egyptian and Ethiopian churches the Nile River is
considered one of the effective connections
That strong then the relations as it leads to some tension between the two countries because
Ethiopia believes that Egypt seeks to control the river tries to build its project over the Blue
Nile means a threat to the Ethiopian national security.
The tension continues even after the revolution of 25th of January 2011because the Nahda
dam which is a clear t

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Publication Date
Mon May 25 2020
Journal Name
International Journal Of Psychosocial Rehabilitation
Strength Training and its Effect in Some Biochemical Variables in the High Jumping of Advanced Players
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The study of biomechanical indicators in the arc of the run and the upgrading stage is one of the important variables that affect the nature of the upgrading and thus affect the result of the race due to the importance of these stages and the consequent variables during the last steps. That’s why, the jump-trainings based on assistant means or body weight positively affect the step-time for each of the three steps in the acceleration arc. As well as, it focuses on the momentary strength of each step at this stage. It also significantly affects the speed of motor performance to suit the activity in which the runner needs to perform perfect steps with high flow in order to convert the horizontal speed to a vertical one. This is achieved thr

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Publication Date
Thu Jul 09 2020
Journal Name
International Journal Of Psychosocial Rehabilitation
Strength Training and its Effect in Some Biochemical Variables in the High Jumping of Advanced Players
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Publication Date
Sun Dec 31 2023
Journal Name
College Of Islamic Sciences
Variation in general formulas in the strength of its foundation and the reasons for the discrepancy
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A legal discourse in the Qur’an and Sunnah is almost devoid of the use of one of the general formulas, and due to its frequent rotation in the tongue of the legislator, the formulas may overlap their members in apparently contradictory provisions, which makes the individual from the general members appear to the beholder to be covered by two contradictory provisions, and this research came to present what might happen to him The legal text interpreter of weighting between the two opposing texts is the strength of the generality that is established by the generality formula, so the two strongest formulas in the inclusion of its members outweigh the weaker of them and precede them, and the research decided that the formulas vary

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Publication Date
Fri Dec 01 2023
Journal Name
Political Sciences Journal
Nation-Building in The Fragile States: Iraq After 2003 as a Model
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The nation-building process in fragile states is complex, often involving multifaceted challenges and opportunities. A pertinent example is Iraq post-2003, which serves as a model to study the intricacies of rebuilding a nation in the aftermath of conflict. During this period, we witnessed a significant international intervention aimed at establishing democratic governance, fostering economic development, and restoring social stability. Iraq’s nation-building journey showcases both successes and shortcomings. Establishing a representative government marked a step towards inclusivity and political participation, yet sectarian tensions persisted, hindering cohesive national identity. Economic initiatives aimed to harness Iraq's oil resou

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