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.
Vocational education has great importance to comprehensive national development as it provides intermediate cadres able of operating the factories and laboratories in the farms and fields beside the work in the fields of health, service, administration and commercial. Due to the importance of this type of education in society, it is necessary to do a qualitative reform of vocational education in order to make the educational staffs get the necessary basic expertise to adapt the requirements of the labor market and try to rearrange and organize the workforce through put long-term economic and social policy through certain planning open to the workforce. The workforces structure according to gradual expansion in all the national ec
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In the present study, cytogenetic and molecular techniques were conducted to detect the chromosomal aneuploidy and the involvement of N and H genes in squamous larynx carcinoma cell line Hep-2.Our results showed that numerical and structural abnormalities were involved in larynx cancer Hep-2.The total number of chromosomes ranging from tripolyploidy in passage187to more than that in passage207.The more frequent chromosomes involved in numerical aberrations were chromosomes1,7,16,17 and 18. Structural chromosomal aberrations were also detected.Deletion of short arm was detected in chromosome 1(del 1p) and the long arm of chromosome 1(del 1q)and 6(del 6q).Gaining on short arms were also recorded in chromosomes 3(3p+) and 12(12p+).At the mole
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The current paper highlights an important character represented by the American president John Tyler 1841 – 1845, who is considered the tenth American president. The importance of this paper lies in identifying his personality in terms of his upbringing and the political activities he practiced before assuming the presidency and his most significant internal achievements, which showed his decisions as a president. He was fully prepared to support national policies since they do not exceed the authorities of the states. With his achievements in the foreign policy, he was capable to draw and define the features of the American foreign relations that were in harmony with the general situation in the United States of America at that time.
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The present work includes investigation of some features of shell morphology; shell size, shell thickness, shell colour of the land snail Monacha cantiana, in addition to the correlation between height and diameter of shell and between shell aperture diameter and shell diameter at four sites within Baghdad Province, Iraq. Also, measurements of three environmental variables were made; soil temperature, soil moisture and soil calcium content in adition to population density. Shell Aperture Index (Ia) and Shell Index (SI) for individuals from size class ranged between (9-12)mm were measured. The results showed that the deference in shell size by using (Ia) within population related to temperature, moisture and population density but, the valu
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This paper proposes two hybrid feature subset selection approaches based on the combination (union or intersection) of both supervised and unsupervised filter approaches before using a wrapper, aiming to obtain low-dimensional features with high accuracy and interpretability and low time consumption. Experiments with the proposed hybrid approaches have been conducted on seven high-dimensional feature datasets. The classifiers adopted are support vector machine (SVM), linear discriminant analysis (LDA), and K-nearest neighbour (KNN). Experimental results have demonstrated the advantages and usefulness of the proposed methods in feature subset selection in high-dimensional space in terms of the number of selected features and time spe
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Expansion the engineering consultancy offices in the universities of Iraq, about (14) offices, leading to increas the competition between them, especially after the great trends of Iraqi government agencies to use the academic experiences and their efficiencies in general, due to non-existence of the engineering qualification in the government institutions to do the engineering designs ,supervision of projects and other engineering works which are practicing by the engineering consultancy offices in order to get the best performance of the work.Within this serious competition, needing a specific approach to enable government agencies to choose the optimal and alternative consultancy office to meet specific project and not rely on cronyis
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Public debt has posed a major challenge to both developing and developed countries, which has focused attention on the optimal limits (threshold of debt) and its determinants.
The study examines the effect of the Public bank debt on the foreign reserves and the work of the foreign reserve as a limitation on the process of bank debt (part of the internal debt) for the period (2017-2004), in addition to finding the type and nature of the relationship between them according to the hypotheses of the study, Public bank debt and foreign reserves.
The study was based on data from the Iraqi banking sector, which showed that Iraq has a foreign reserve in line with internat
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The research entitled "The political changes and economic developments in contemporary Turkish Backgrounds, manifestations and future possibilities" consists of the introduction, four sections and conclusions. The background details, its developments, and the transformation in the economic sector in Turkey were reviewed. The first section concentrated on the brief introduction about the political developments which happened since the independence of Turkey at 1923 with the highlight on the years after the receipt of the Freedom and Justice Party (Ak PARTi) the Turkish Government rule. The second section demonstrated the reality of Turkish economy before 2002, while the
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