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.
In this paper, the researcher suggested using the Genetic algorithm method to estimate the parameters of the Wiener degradation process, where it is based on the Wiener process in order to estimate the reliability of high-efficiency products, due to the difficulty of estimating the reliability of them using traditional techniques that depend only on the failure times of products. Monte Carlo simulation has been applied for the purpose of proving the efficiency of the proposed method in estimating parameters; it was compared with the method of the maximum likelihood estimation. The results were that the Genetic algorithm method is the best based on the AMSE comparison criterion, then the reliab
... Show More
Background: Bone defect healing is a multidimensional procedure with an overlapping timeline that involves the regeneration of bone tissue. Due to bone's ability to regenerate, the vast majority of bone abnormalities can be restored intuitively under the right physiological conditions. The goal of this study is to examine the immunohistochemistry of bone sialoprotein in order to determine the effect of local application of bone sialoprotein on the healing of a rat tibia generated bone defect. Materials and Methods: In this experiment, 48 albino male rats weighing 300-400 grams and aged 6-8 months will be employed under controlled temperature, drinking, and food consumption settings. The animals will be subjected to a surgical procedure o
... Show More
(1)
(1)
The adequacy of diagnostic tests, together with trichomoniasis associated clinical symptoms, were investigated in females suffering vaginitis, and they were referred to the Gynecology Department, Al-Yarmouk Teaching Hospital during the period December 2004 – June 2005. The total number of patients was 250 cases (age range: 18 - 52 years), and each patient was examined using a sterile speculum to obtain vaginal swabs for examination. The diagnosis with T. vaginalis was done in many methods. The direct methods included wet and stained (Leishman's stain) examinations and cultivation in different culture media (Kupferberg Trichomonas Broth Base;, Trichomonas Agar Base; TAB and Trichomonas Modified CPLM), while the indirect methods were serol
... Show More
(1)
Recently, there has been an increasing advancement in the communications technology, and due to the increment in using the cellphone applications in the diverse aspects of life, it became possible to automate home appliances, which is the desired goal from residences worldwide, since that provides lots of comfort by knowing that their appliances are working in their highest effi ciency whenever it is required without their knowledge, and it also allows them to control the devices when they are away from home, including turning them on or off whenever required. The design and implementation of this system is carried out by using the Global System of Mobile communications (GSM) technique to control the home appliances – In this work, an ele
... Show More
(7)
(5)
In this work a model of a source generating truly random quadrature phase shift keying (QPSK) signal constellation required for quantum key distribution (QKD) system based on BB84 protocol using phase coding is implemented by using the software package OPTISYSTEM9. The randomness of the sequence generated is achieved by building an optical setup based on a weak laser source, beam splitters and single-photon avalanche photodiodes operating in Geiger mode. The random string obtained from the optical setup is used to generate the quadrature phase shift keying signal constellation required for phase coding in quantum key distribution system based on BB84 protocol with a bit rate of 2GHz/s.
E-commerce is the most important result of information technology in this day and age, has resulted in the use of commercial transactions to changes in economic, social, and psychological, and produced a new type of shopping, jobs, and create new job opportunities, and changed the traditional work environment. The challenge currently facing economic units is how to transfer this technology and its integration within the community, especially after the massive developments that have occurred in the areas of commercial and congested markets units, the economic and the products and services the many and varied and intensified competition among these units to achieve a profit, leading to the emergence of e-commerce as on
... Show More
In this paper, Bayes estimators of the parameter of Maxwell distribution have been derived along with maximum likelihood estimator. The non-informative priors; Jeffreys and the extension of Jeffreys prior information has been considered under two different loss functions, the squared error loss function and the modified squared error loss function for comparison purpose. A simulation study has been developed in order to gain an insight into the performance on small, moderate and large samples. The performance of these estimators has been explored numerically under different conditions. The efficiency for the estimators was compared according to the mean square error MSE. The results of comparison by MSE show that the efficiency of Bayes est
... Show More
(2)
Soil movement resulting due unsupported excavation nearby axially loaded piles imposes significant structural troubles on geotechnical engineers especially for piles that are not designed to account for loss of lateral confinement. In this study the field excavation works of 7.0 m deep open tunnel was continuously followed up by the authors. The work is related to the project of developing the Army canal in the east of Baghdad city in Iraq. A number of selected points around the field excavation are installed on the ground surface at different horizontal distance. The elevation and coordinates of points are recorded during 23 days with excavation progress period. The field excavation process was numerically simulated by using the finite
... Show MoreThis work has been done to prepare a series of new alkene compounds derived from 4-thiozolidinones by substituting different aldehydes, P-acetamido-phenol, and 2-mercapto-benzoimidazole, which were used as starting materials to form ester [I]a,b and then make hydrazides [II]a,b, which were used to prepare 1, 3, and 4-oxadiazoles [III]a,b, which were then used for prepared Schiff bases [IV]a-f, The next step was the synthesis of 4-thiazoldinone derivatives [V]a-f from Schiff bases. The final step was the synthesis of alkenes [VII]a-f, the prepared derivatives were identified with spectral methods (FT-IR, 1H-NMR, mass, and CHNS). The antibacterial activity of the prepared derivatives was evaluated against four types of bacteria, pos
... Show More
(2)