Background: The demand for better esthetic during orthodontic treatment has increased nowadays, so orthodontists starting using esthetic arch wires, brackets and ligatures.Tooth colored brackets were introduced in different types of materials. Sapphire ceramic brackets are one type of esthetic brackets and their color stability remains the main concern for the clinicians and patients at the same time. The present study design to evaluate the effect of three different staining materials (pepsi, black tea and cigarette smoke) on the stainability of sapphire ceramic brackets bonded with three types of light cure orthodontic adhesives which include: Resilience, Enlight and Transbond. Materials and Methods: The sample consisted of three hundred sixty sapphire brackets. The brackets were divided according to bonding materials into three groups each group consist of one hundred twenty brackets, then each subgroup farther subdivided into four groups according to the material they were immersed (distilled water, black tea, Pepsi and cigarette smoke) with thirty brackets each, then Each group with ten brackets farther subdivided according to time interval of immersion in each media into three groups one day, seven days and fourteen days at 37°C in the incubator.A UV-Visible spectrophotometer (Shimadzu, UV -1800) was used to perform a light absorption test. Results: ANOVA and LSD post Hoc tests were used to identify the significant effects of the staining materials at a significance level P ≤ 0.05.It was found that the immersion time gradually influenced the color stability of the adhesive materials with sapphire brackets with the highest activity observed at fourteen days interval. The brackets bonded with Resilience light cure adhesive are the most type affected by staining materials, then followed by the brackets bonded with Transbond and finally the brackets bonded with Enlight light cure adhesive. For the staining materials it was found that the cigarette smoke is the most powerful staining material, followed by tea and finally pepsi. Conclusions: From the above result we can conclude that the type of adhesive must take in consideration when the esthetic brackets have been used.
The study seeks the relationship between the mathematical-procedural Knowledge and the logical-mathematical intelligence among students at the third stage in mathematics department. To this end, three questions were arisen: what is the level of mathematical-procedural Knowledge among the third stage students in mathematics department regarding their gender? Do male or female students have more logical-mathematical intelligence and are there significant differences base on their gender? What kind of correlation is between the level of mathematical-procedural Knowledge and the logical-mathematical intelligence of male and female students in the third stage in the mathematics department? A sample of (75) male and female students at the thir
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A paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat metho
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Purpose: This study aims to shed the light on allusions to real lab rats in Dashner’s trilogy: The Maze Runner (2009), The Scorch Trails (2010), and The Death Cure (2011). It also aims to trace the historical documents and chronicles essential to reveal the justifications behind the vague political and scientific crimes. Methodology: The researchers have used the literary analytical approach to study and analyze selected prominent aspects from each novel; such as the concept of lab rats and genocide crimes in The Maze Runner; references to weather experiments, the climate change conspiracy, gas chambers, and the Holocaust in The Scorch Trails; and finally, the man-made diseases and biological weapons in The Death Cure. Results
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Resumen
La literatura infantil es uno de los géneros literarios que incluye varios estilos de la prosa, cuento, poesía etc. Ha florecido en el siglo XX con la aparición de los autores que dedicaron la mayor parte de su tiempo para escribir sus composiciones para los niños, tomando de las leyendas y las historias populares y religiosas a fin de hacerla sencilla para ser correspondiente con sus edades. La traducción de la literatura infantil lleva a ampliar los horizontes y los conocimientos de los niños cuando conocen las costumbres y las tradiciones de los pueblos. Se sabe que hay muchas dificultades respecto al proceso de la traducirían en cuanto a la comprensión de l
... Show MoreSeveral problems have emerged as a result of urban expansion or the connection of urban areas with rural areas. This process has led to the urbanization of rural areas, and to have overlapping edges and margins of areas, which were outside the basic design of the city. Accordingly, the present research assumes that the accelerating growth of Baghdad population has contributed significantly to the process of unplanned urbanization. Thus, the study aims to examine the factors that have led to an increase of urban sprawl at the expense of the agricultural land. The study has thus adopted the descriptive, analytical, and historical approaches relying on the simple linear regression method to predict the phenomenon of urban expansion and its
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An investigation was provided in this work for the host range of brown soft scale Coccus hesperidum Linnaeus in Baghdad Province. Five plant species were found infected by this insect, three of these species, Citrusaurantium L. (Rutaceae); Nerium oleander L. (Apocynaceae); Ficuscarica L. (Moraceae) reported earlier, and the remaining two, Dahlia pinnata Cav. (Asteraceae) and Myrtuscommunis L. (Myrtaceae) are recordedhere for the first time as host plants for this pest.
The current research aimed at deducing the psychological contents of Suliman dialogue with the Hodhod and statement applications in school counseling. The researcher followed the Islamic approach in the search, which deals with the study of events, phenomena and practices through a broad understanding of Islamic principles and limitations associated with the general framework of Islam. In addition to the deductive approach is derived from a sub-rule is a general provision.
The research revealed many of the psychological contents, including: the importance of continuing care counselor psychological learners, and follow-up field to their problems, conditions, listen good horseshoe to defend himself, clarify the motives of his ac
The aim of this paper is to derive a posteriori error estimates for semilinear parabolic interface problems. More specifically, optimal order a posteriori error analysis in the - norm for semidiscrete semilinear parabolic interface problems is derived by using elliptic reconstruction technique introduced by Makridakis and Nochetto in (2003). A key idea for this technique is the use of error estimators derived for elliptic interface problems to obtain parabolic estimators that are of optimal order in space and time.
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