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.
The paper comprise comparative palynological study of (11) species belong to the genus Echinops L. in Iraq i.e( E.armatus Boiss. & Hausskn ، E.bicolor Nabelek. ، E.cephalotes DC., E.haussknetchii Boiss. ، E.mosulensis ، Rech. ،
E.nitens Bornm. ، E.orientalis Trautv., E.parviflorous BOISS & BUHSE ،
E.spinossisms Turra . ، E.tenuisectus Rech. ، E.viscosus DC.، Pollen grain were found to be Tricolporate and with spherical shaped ,in polar view the grain found to be Interangular , while in equatorial view the grain found to be ellipsoid .
Gypsiferous soil deposits (Gypcrete) are weakly consolidate earthy mixture of secondary gypsum, sand and clay. It is formed in arid and semi- arid area with annual precipitation rainfall less than 400mm. These sediments occur in surface and subsurface in region of little rainfall and rapid evaporation. This research deals with the study of gypcrete in Alexandria to improve the mineralogical and geochemical properties of the gypcrete. The gypcrete soil is used as raw material to produce the plaster for building purposes. Three samples of gypcrete were chemically and geochemically analyzed. The common mineral is howed in 0-0.5m Gypsum followed by Calcite in 0-1m and Quartz in 1-1.5m due to leaching and infiltration by rainfall as well as it
... Show MoreIn this paper, we study flow of photons rate production in a quark-gluon QG plasma. General theory of this study is based on the field theory for hard interaction. The kinetic of photons production from hard interaction in charm with anti-top to production photons with gluon due to plasma phase at high temperatures (150, 200,250,300 and 350 MeV) .It has been investigated and studied using the postulate of quantum chromodynamic theory QCD .The photons production rate of hard photons with( GeV) are insensitive to strength coupling and depend mainly on the temperature of system T . Despite the different critical temperature (150 and 190MeV) comes, we ï¬nd that same order of flow rate photons magnitude in both cases. In both cases, the f
... Show MoreThe ambient temperature is the major parameter that influences wind speed. When temperature rises, air will be extended and wind will flow with different speeds in all directions, increasing of temperature means that wind speed will be increased and vice versa. The relative humidity and atmospheric pressure affected with temperature, too. Climate changes making significant effects on the atmospheric temperature. In this project, the data of thirty four years (1981 – 2004) has been analyzed to get an idea about the changes occurred in the meteorological parameters in Al-Nasiriya city, which was chosen because it has a distinctive wind speed.
The present research deals with the species Dionysia odora Fenzl.
(sy noname:Dionysia michauxii) it covers all its attributed and detailed. The plants are studied
in the college of A griculture/University of Sulaimaniya Herbar ium. The Palynology, Ecology
was given also. The sp ecimens of the plant collected and identified by Saman Abdulrahmad
Ahmad.
The present study aimed to investigate the morphological description and histological structure of kidney in adult albino mice (Mus musculus), The anatomical study revealed that the kidney in albino mice is represented by bean-like shape, smooth with red to brown color, It is situated within the anterior half of abdominal cavity under the diaphragm on both sides of vertebral column. The kidney is covered by capsule of loose connective tissue with mean thickness of (9.6±0.5) micrometer. Histological examination revealed that albino mice kidney tissue differentiated into cortex and medulla, the cortex contains glomeruli with mean diameter of (50.5±1.9) micrometer densely distributed at the peripheral area of the cortex ,
... Show MoreObjective :.
1-Find out the prevalence of alcohol and drugs addiction in two different years before and after the last
war i.e. in 2002 and in 200. 2-Study the association between the addiction
and some variables. 3-Identify the prescribed drugs and other substances that
have been abused
Methodology : A retrospective study has been conducted involving the in-patients at addiction unit-IbnRushd
psychiatric hospital in Baghdad by applying the semi-structured form based on ICD-10 criteria
of addiction and dependency with the confirmation of the specialist psychiatrist diagnosis of
dependency. Data concerning each patient admitted in the hospital was gathered to have an idea about
the problem of addiction (drugs an
the study covered theoretical concering parial molal volume the applicability of jones-dole equation
The Tamarix aphylla is a wild perennial shrub with erect stems that are long and glabrous. They have leaves that are simple, alternate, sheathed, and the apex of the blade is acuminate. And a scaly clawed bract and the the inflorescences were simple, spike-like. The pistil consists of ovary pyramidal, 3 styles, and 3 stigmas. The androecium consists of five stamens that are antisepalous. The perianth was distinct with five sepals and five petals. The fruits were capsule-shaped, pyramidal, and smooth. The seed has an apical pappus of unicellular hygroscopic hairs; endosperm is absent. The anatomical study of the leaves contained a uniseriate epidermis consisting of one layer of elongated cells covered by a layer of papillary cuti
... Show MoreThe importance of vibrations in rotating rotors in engineering applications has been examined, as has the best approach to interpreting vibration data. The most extensively used analytical approaches for rotating shaft vibration analysis have been investigated. In this research, a detailed study was made of the Rayleigh and Dunkerley methods due to their importance in the special calculations to find the amplitude of vibrations in the rotation system. The multi-node method was used to calculate both Dunkerley's and Rayleigh's methods. An experimental platform was built to study the vibrations that occur in the rotating shafts, and the results were compared with theoretical calculations and with different distances of the bearings. It pro
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