Background: With the increasing demand on esthetic orthodontic appliances, discoloration of clear elastomeric chains and modules remains an issue which concerns both orthodontics and patients. This in vitro study was conducted to evaluate the effect of exposing stretched clear elastomeric chains from six different companies (Ortho Technology, Ormco, Ortho Organizer, American Orthodontics, Opal and G&H companies) to three types of dietary media (tea, coffee and turmeric). Materials and methods: A total of 960 lengths of six modules were cut from short type elastomeric chain; 160 pieces from each brand. The specimens were stretched 50%, placed on plastic boards, and incubated in water at 37°C for 1 day, 7 days, 14 days and 28 days. Once a day, the specimens were immersed for ten minutes in the testing dietary media, washed and then returned back to the water container. Color measurements were made before and after incubation of the specimens. Digital image were taken by an SLR digital camera and the color changes were calculated according to CIE L*a*b* color space system by Adobe Photoshop program. The resulting data were statistically analyzed using ANOVA and LSD tests. Result: Elastomeric chains from AO, Opal and G&H companies were the most brands prone to discoloration. Ortho Organizers and Ortho Technology chains were the least prone to discoloration. Tea, coffee and turmeric solutions discolored elastomeric chains from all companies in a variable degree, however turmeric caused significantly more discoloration, followed by tea and least by coffee. The amount of discoloration caused by tea and coffee increases gradually to peak at 28 days, while most of the discoloration caused by turmeric was in the first day and reached a plateau in a week. Conclusion: To decrease the discoloration of clear elastomeric chains the consumption of colored dietary media especially spices like turmeric are to be discouraged.
In this work, we present the notion of a multiplier on AT-algebra and investigate several properties. Also, some theorems and examples are discussed. The notions of the kernel and the image of multipliers are defined. After that, some propositions related to isotone and regular multipliers are proved. Finally, the Left and the Right derivations of the multiplier are obtained
In this paper we will study some of the properties of an operator by looking at the associated S-act of this operator, and conversely. We look at some operators, like one to one operators, onto operators. On the other hand, we look at some act theoretic concepts, like faithful acts, finitely generated acts, singular acts, separated acts, torsion free acts and noetherian acts. We try to determine what properties of T make the associated S-act has any of these properties.
Constructing a fine 3D geomodel for complex giant reservoir is a crucial task for hydrocarbon volume assessment and guiding for optimal development. The case under study is Mishrif reservoir of Halfaya oil field, which is an Iraqi giant carbonate reservoir. Mishrif mainly consists of limestone rocks which belong to Late Cenomanian age. The average gross thickness of formation is about 400m. In this paper, a high-resolution 3D geological model has been built using Petrel software that can be utilized as input for dynamic simulation. The model is constructed based on geological, geophysical, pertophysical and engineering data from about 60 available wells to characterize the structural, stratigraphic, and properties distribution along
... Show MoreConstructing a fine 3D geomodel for complex giant reservoir is a crucial task for hydrocarbon volume assessment and guiding for optimal development. The case under study is Mishrif reservoir of Halfaya oil field, which is an Iraqi giant carbonate reservoir. Mishrif mainly consists of limestone rocks which belong to Late Cenomanian age. The average gross thickness of formation is about 400m. In this paper, a high-resolution 3D geological model has been built using Petrel software that can be utilized as input for dynamic simulation. The model is constructed based on geological, geophysical, pertophysical and engineering data from about 60 available wells to characterize the structural, stratigraphic, and properties distri
... Show MoreThe work in this research presents an experimental and a theoretical study to obtain the effect of using a low permeability geosynthetic material on the longitudinal and lateral coefficients of dispersion. This would have its effect on the contaminants migration through an isotropic, homogenous and saturated soil. The first stage of this research involves the study of the geosynthetic material and in calculating the longitudinal and lateral coefficients of dispersion for an Iraqi sandy soil by using an experimental set-up to simulate the processes. To investigate the effect of using a geosynethtic material on the dispersion coefficients, the test was conducted for each velocity that was used in the experimental work and as follows: with
... Show MoreBackground: Moyamoya disease (MMD) is a rare cerebrovascular disease characterized by bilateral stenosis starting at the supraclinoid internal carotid artery (ICA), with the development of a collateral network of vessels. It is an established cause of stroke in the pediatric age group. Despite its increasing prevalence in various parts of the world, it remains largely underrecognized in the Middle East, particularly in Iraq. This is the first case of MMD in an Iraqi patient undergoing surgery. Case description: A 12-year-old boy presents with a 3-months history of progressive behavioural changes. MRI revealed diffuse infarcts of different ages. MRA and CT angiography revealed extensive asymmetrical steno-occlusive changes of t
... Show MorePlentiful of healthcare practice is based on a disease/treatment approach rather than a prevention one. That is, the predominant focus is on treating existing symptoms and conditions that bring the patient to healthcare setting. There is no doubt about the significance of this approach for acute conditions, but there is some question whether this is the most efficient and effective way of distributing healthcare for increasing number of diseases and limited resources.
The evidences from everywhere have showed the profound cost benefit of prevention in healthcare practice. Healthy community, therefore, is the ultimate aim in any health services planning. The priority of care giver is shifted now to promote health and prevent
... Show MoreIn this paper, a method for hiding cipher text in an image file is introduced . The
proposed method is to hide the cipher text message in the frequency domain of the image.
This method contained two phases: the first is embedding phase and the second is extraction
phase. In the embedding phase the image is transformed from time domain to frequency
domain using discrete wavelet decomposition technique (Haar). The text message encrypted
using RSA algorithm; then Least Significant Bit (LSB) algorithm used to hide secret message
in high frequency. The proposed method is tested in different images and showed success in
hiding information according to the Peak Signal to Noise Ratio (PSNR) measure of the the
original ima
Experiments were carried out to investigate natural convection heat transfer in an inclined uniformly heated circular cylinder . The effects of surface heat flux and angle of inclination on the temperature and local Nusselt number variations along the cylinder surface are discussed . The investigation covers heat flux range from 92 W/m² to 487 W/m², and angles of inclination 0° ( horizontal) , 30° , 60° and 90° (vertical) . Results show an increase in the natural convection as heat flux increases and as angle of inclination moves from vertical to horizontal position. An empirical equation of average Nusselt number as a function of Rayliegh number was deduced for each angle of inclination .