Background: Esthetic treatment is the options of patient seeking orthodontic treatment. Therefore this study was conducted to measure the concentration of Aluminum, Nickel, Chromium and Iron ions released from combination of monocrysralline brackets with different arch wires immersed in artificial saliva at different duration, to evaluate the corrosion point on different parts of the orthodontic appliances before and after immersion in artificial saliva, and to evaluate the corrosion potential of each group of the orthodontic appliances. Material and methods: Eighty orthodontic sets prepared. Each set represents half fixed orthodontic appliance, from the central incisor to the first molar, for the maxillary arch, each set consisted of molar band, five brackets, half arch wire and ligature elastic.These sets are divided into two groups: Group A: with monocrystalline brackets divided into five subgroups (each subgroup has ten sets), but differ in arch wires, as numbered stainless steel, nickel-titanium, thermally activated, coated stainless steel and coated nickel-titanium arch wires respectively. Group B: with stainless steel brackets divided into three subgroups (also each subgroup has ten sets), but differ in arch wires, as numberedstainless steel, nickel-titanium, and thermally activated arch wires respectively. Used optical microscope to check the corrosion points, and used potentiostat techniques to indicate corrosion rate and tendency. Results: The greatest concentration of Aluminum and nickel ions release during the 1st week in group A, then sharply decreased in the 2nd week. The release of chromium ion released increase with increase intervals, while iron ion released decrease with increase time. Both nickel and chromium ions increase with increase intervals in group B,while iron increase to the maximum at 3rd weeks, then began to degrease. Optical microscope displayed pitting, crevices, and intergranular corrosion. Potentiostat techniques indicated that increase corrosion when used stainless steel and coated nickel titanium than others arch wires with group A, while corrosion increase with nickel titanium than stainless steel arch wires with group B. Conclusions: Non-significant difference in the total nickel, chromium and iron release in group B. Aluminum and iron increase in A4 and A5, while nickel and chromium increase in A1 and A2.The total released amounts of metals ions in both groups were less than the amounts of daily intake.
Energy is one of the components of the national security of countries and is of particular importance to the industrialized countries, including Germany. Energy policy includes many areas and has an impact on various sectors such as the environment, climate, agriculture and others. During the past few years, Germany has witnessed many transformations, the most important of which is the energy transition towards renewable energy, and it was strengthened in the strategy that was It was developed in 2010, which aims to achieve a long-term energy transformation, and sales of the German energy technology sector have evolved from 2010 to 2020, and this issue is related on the other hand to the concept of energy security and because of its strateg
... Show MoreResearch title: Ruling on abortion in Sharia and law.
The importance of research: Projection is of great importance because it touches the life of a living being who enjoys human qualities. However, this organism often wastes its rights and does not protect its human beings. These souls are lost in millions by the sake of casual desire or hidden desire.
The research plan: The research dealt with an introductory topic, four topics, and in each topic there are demands, branches, and a conclusion.
The most important findings of the study: The ruling on aborting the fetus in the Sharia is only permissible (and the necessity is valued at its va
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Precarity means the lack of social and economic networks; a considerable exposure to danger and harm. Minority groups are precariat for they lack rights and full citizenship. Precarity is related, states Judith Butler, with the individual’s performativity, and his ability to perform his gender role. Toni Morrison continually goes to past to retell the history of African Americans. The issues of race, gender and national identity are recurrent in her work. Reading her book Home (2012) evokes the idea of precarity and performativity since the two main characters, Frank and Cee are precarious characters that fail to perform their gender role properly, and eventually are exposed to hazard and harm. This research displays how African American
... Show MoreBackground .To know the incidence of adenoid hypertrophy in adults causing nasal obstruction and other nasal complains.
Methods.Prospective studyof(140 ) adult patientstheir main chief complaint were nasal obstruction , presented to Otolaryngology department at Aljumhory Teaching Hospital in Mosul , from the period (september 2010 to september 2011) ,their age ranged from (21 to 53) years . They were investigated clinically, radiologicaly ,and nasal endoscopic examination was carried out (rigid and fibro-optic ) . Adenoidectomy was performed for those with adenoid hypertrophy and sent for histopathological study .
Results:. we found adenoid enlargement in(24) patients (17.14%),in addition to nasalobstruction they were also complain
This research is the subject of "Domination and Motivation in the Sculptures of Mona the Saudi" to the study of an accomplished Arab sculptor with its varied sculptural activity between the works of the exhibition and the works of the squares, as well as its distinguished place among the contemporary Arab sculptors. This research is divided into four chapters:
The first chapter deals with the general methodological framework of the research in terms of the research problem which is focused on the question: What is the hegemony and motivation in the sculptures of Mona Saudi? The importance of research and the need for it, including the technical scientific material concerned with the sculptural achievement of t
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In this paper, we use concepts and results from percolation theory to investigate and characterize the effects of multi-channels on the connectivity of Dynamic Spectrum Access networks. In particular, we focus on the scenario where the secondary nodes have plenty of vacant channels to choose from-a phenomenon which we define as channel abundance. To cope with the existence of multi-channels, we use two types of rendezvous protocols: naive ones which do not guarantee a common channel and advanced ones which do. We show that, with more channel abundance, even with the use of either type of rendezvous protocol, it becomes difficult for two nodes to agree on a common channel, thereby potentially remaining invisible to each other. We model this
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