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.
Abstract:
The distribution or retention of profits is the third decision among financial management decisions in terms of priority, whether at the level of theory or practice, as the issue of distribution or retention is multi-party in terms of influence and impact, as determining the optimal percentage for each component is still the subject of intellectual debate because these decisions are linked to the future of the organization and several considerations, The research focus on the nature of the policies followed by the Iraqi banking sector As the sample chosen by the intentional sampling method was represented by the Commercial Bank of
... Show MoreThe research aims to study and definition of the concept of creative accounting and motives adopted by the management of companies to achieve their own goals and their impact on the reliability of the financial statements and the tax settling accounts and whether that tax administration is able to detect and limit the creative accounting practices and impose legal sanctions deterrent against companies The research has come to a set of conclusions, including:
- The administration motives in the use of creative accounting methods, some internal motives related to the interests of the administration in maximizing profits to increase incentives and rewards, others are external, such as the impact on stock prices or reduce the am
A New ligand, N-(2-oxo-1,2- Dihydropyrimidin-4- ylcarbamothioyl) Acetamide (DPA) was prepared by reaction of iso thiosyanate derivative with Cytosine. The ligand has been characterized through elemental analysis, H1 NMR, C13NMR, FT-IR, and UV Visible spectra, such ligand’s transition metal complexes have been characterized through conductivity measurement, FT-IR, UV Visible spectra and magnetic susceptibility, all the complexes of this ligand are solid crystal and molar ratio (2:1) (ligand: metal). The form of molecular for these complexes octa hedral. The general formula [M(DPA)2Cl2], where M+2 = (Mn, Co, Ni, Cu, Zn, Cd, Hg).
A study of taxonomic quality of soil algae was conducted with some environmental variables in three sites of local gardens (Kadhimiya, Adhamiya and Dora) within the governorate of Baghdad for the period from October 2016 to March 2017. The study identified 28 species belonging to 16 species in which the predominance of blue green algae (18 species) Followed by Bacillarophyta algae (7 species) and three types of Chlorophyta. The study showed an increase in species of Oscillatoria. The results showed no significant differences between sites in temperature, pH and relative humidity, while there were clear differences between sites for salinity and nutrient The study showed a difference of irrigation water quality and use of different fertilize
... Show MoreMicroalgae have been used widely in bioremediation processes to degrade or adsorb toxic dyes. Here, we evaluated the decolorization efficiency of Chlorella vulgaris and Nostoc paludosum against two toxic dyes, crystal violet (CV) and malachite green (MG). Furthermore, the effect of CV and MG dyes on the metabolic profiling of the studied algae has been investigated. The data showed that C. vulgaris was most efficient in decolorization of CV and MG: the highest percentage of decolorization was 93.55% in case of MG, while CV decolorization percentage was 62.98%. N. paludosum decolorized MG dye by 77.6%, and the decolorization percentage of CV was 35.1%. Metabolic profiling of
... Show MoreRouting protocols are responsible for providing reliable communication between the source and destination nodes. The performance of these protocols in the ad hoc network family is influenced by several factors such as mobility model, traffic load, transmission range, and the number of mobile nodes which represents a great issue. Several simulation studies have explored routing protocol with performance parameters, but few relate to various protocols concerning routing and Quality of Service (QoS) metrics. This paper presents a simulation-based comparison of proactive, reactive, and multipath routing protocols in mobile ad hoc networks (MANETs). Specifically, the performance of AODV, DSDV, and AOMDV protocols are evaluated and analyz
... Show MoreBackground: Chronic otitis media (COM) of mucosal or squamous type is a common problem in otolaryngology practice, the active form of COM is characterized by discharge of pus and is treated by antibiotics to start with, the appropriate antibiotic should be prescribed to avoid antibiotic abuse and guarantee good outcome. Objectives:The objective of this study is to identify the causative organisms of active chronic active otitis media both (mucosal, squamous) type and test their sensitivity to various anti- microbial agents &compare with abroad studies.Methods:A prospective study was done on eighty patients, different ages and sexes were taken and carful history and examination was done, examination under microscope was done with carf
... Show MoreThe use of non-parametric models and subsequent estimation methods requires that many of the initial conditions that must be met to represent those models of society under study are appropriate, prompting researchers to look for more flexible models, which are represented by non-parametric models
In this study, the most important and most widespread estimations of the estimation of the nonlinear regression function were investigated using Nadaraya-Watson and Regression Local Ploynomial, which are one of the types of non-linear
... Show MoreSoftware-defined networking (SDN) presents novel security and privacy risks, including distributed denial-of-service (DDoS) attacks. In response to these threats, machine learning (ML) and deep learning (DL) have emerged as effective approaches for quickly identifying and mitigating anomalies. To this end, this research employs various classification methods, including support vector machines (SVMs), K-nearest neighbors (KNNs), decision trees (DTs), multiple layer perceptron (MLP), and convolutional neural networks (CNNs), and compares their performance. CNN exhibits the highest train accuracy at 97.808%, yet the lowest prediction accuracy at 90.08%. In contrast, SVM demonstrates the highest prediction accuracy of 95.5%. As such, an
... Show MoreThe research has designed for studying the relationship between manufacturing strategy and its flexibility under the flexible manufacturing system with their reflection on the competitive environmental performance of the firm. To interpret and tackle the problem, a hypothesis has formulated stating that “ the competitive performance of a firm is interpreted by the manufacturing strategy and flexibility which are derived from the firm and its business strategies under the flexible manufacturing system”. Related literatures with their theoretical dissertations, which enhanced the thoughtful content, have analyzed. An illustrative case study on the flexible manufacturing system at Toyota Motors Corporation working at the g
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