Background: The aim of this study was to evaluate and compare the static frictional forces produced by monocrystalline ceramic (sapphire) bracket and polycrystalline ceramic bracket. Materials and methods: one hindered twenty brackets/segment of archwire combinations were used, each bracket/segment of archwire combination was tested 10 times. The tests were performed in a universal testing Instron machine. The data was submitted to in depended t-test. Results: The independent sample t-tests showed a highly significant difference in the static frictional forces between monocrystalline ceramic (sapphire) bracket and polycrystalline ceramic bracket. Conclusion: According to the biomechanical result gained from the present study, the monocrystalline ceramic (sapphire) brackets produced lower static friction level than polycrystalline ceramic bracket.
The multimetric Phytoplankton Index of Biological Integrity (P-IBI) was applied throughout Rostov on Don city (Russia) on 8 Locations in Don River from April – October 2019. The P-IBI is composed from seven metrics: Species Richness Index (SRI), Density of Phytoplankton and total biomass of phytoplankton and Relative Abundance (RA) for blue-green Algae, Green Algae, Bacillariophyceae and Euglenaphyceae Algae. The average P-IBI values fell within the range of (45.09-52.4). Therefore, water throughout the entire study area was characterized by the equally "poor" quality. Negative points of anthropogenic impact detected at the stations are: Above the city of Rostov-on-Don (1 km, higher duct Aksai) was 38.57 i
... Show MoreThe photooxidative degradation process of plastics caused by ultraviolet irradiation leads to bond breaking, crosslinking, the elimination of volatiles, formation of free radicals, and decreases in weight and molecular weight. Photodegradation deteriorates both the mechanical and physical properties of plastics and affects their predicted life use, in particular for applications in harsh environments. Plastics have many benefits, while on the other hand, they have numerous disadvantages, such as photodegradation and photooxidation in harsh environments and the release of toxic substances due to the leaching of some components, which have a negative effect on living organisms. Therefore, attention is paid to the design and use of saf
... Show MoreStabilization of phenol trapped by agricultural waste: a study of the influence of ambient temperature on the adsorbed phenol
raqi species of (Euphorbia lathyris F. Euphorbiaceae) have been used in the present study to evaluate genotoxicity of petroleum ether fraction in two doses (100mg/kg and 200mg/kg) on bone marrow cells in mice for seven successive days, comparing their effects with a positive control (methotrexate at a dose 20 mg/kg). Both doses of petroleum ether fraction of Euphorbia Lathyris significantly decrease mitotic index (P<0.05) compared to dimethylsulfoxide (negative control) group. For total chromosomal aberration, the petroleum ether fraction of Euphorbia lathyris (in both doses) produced significant increase (P<0.05) compared to dimethyl sulfoxide (negative control) group .at the same time, 20mg/kg methotrexate significantly increases (P<0.05)
... Show MoreImpairment of financial assets defined according to IFRS 9 as the difference between all contractual cash flows that are due to an entity in accordance with the contract and all the cash flows that the entity expects to receive, the entity should estimates all the cash flows through looking to the contract terms during the life time period of the assets or for shorter period if possible, the cash flow should include the amounts of selling any collateral taken or any other enhancement. On the other hand, the Central bank of Iraq guidelines regards impairment differ from the IFRS 9 that’s does not consider the collateral value on calculating the impairment that’s effects on the net profit through recognizing exaggerated loss an
... Show MoreThe Vogue of the Restoration Comedy of Manners and George Etherage's The Man of Mode; or, Sir Fopling Flutter
Autorías: Omar Khalid Yasir, Marwa Husein Ali, Aws Miqdad Jafar Hassan Alhusseini. Localización: Retos: nuevas tendencias en educación física, deporte y recreación. Nº. 70, 2025. Artículo de Revista en Dialnet.