Background: Sliding mechanics is widely used during orthodontic treatment. One of the disadvantages of this mechanics is the friction generated at the bracket/archwire interface, which may reduce the amount of desired orthodontic movement obtained. The aim of the present in vitro study was to evaluate and compare the static frictional forces produced by two passive self-ligating brackets stainless-steel and hybrid and two conventional brackets stainless-steel and monocrystal ligated with stainless-steel ligature wire at two degrees of torque(zero and twenty) under dry condition. Materials and method: One hundred and sixty brackets were used in this study divided into four groups each group consisted of forty brackets these are: Two self-ligating (stainless-steel and Hybrid) while the two conventional types are the (stainless-steel and monocrystal).twenty of each group examined with 0.016"x0.022"archwire, ten at 0? torque and ten at 20? torque while the other twenty of each group examined with 0.019"x0.025", ten at 0? torque and ten at 20? torque. Results: There was a significant different between all groups except in case when self-ligating brackets (both types) ligated to both wires at 0?torque there was no significant difference. Conclusions: The self- ligating brackets produce significantly lower static friction than the conventional types at both degrees of torque. There was no significant different between both self-ligating brackets at0?torque while at 20? torque the stainless- steel self –ligating produce lower static friction than the clear self-ligating type.
The measurement of vitamin B1 in pure and pharmaceutical formulations was proposed by using a straightforward and sensitive spectrophotometric approach. Sulfacetamide (SFA) is diazotized, then coupled with vitamin B1 in alkaline media to produce a colored azo dye complex with a stability constant of 5.597 × 105 L/mol. The product is stable, with a maximum absorption wavelength of 489.5 nm, molar absorptivity of 10108 L/mol∙cm, Sandell's sensitivity of 0.0334 μg/cm2, detection limit of 0.0135 μg/mL, and Beer's law being observed over the concentration range of 0.2–20.0 μg/mL. The stability constant and stoichiometry of the produced azo dye were calculated using the continuous variation (Job's) and mole ratio methods. The suggested ap
... Show MoreBackground: The repair of bone defects remains a major clinical orthopaedic challenge. Bone is a highly vascularised tissue reliant on the close spatial and temporal connection between blood vessels and bone cells to maintain skeletal integrity. This study aimed to study the efficacy of Panax ginseng as a osteoinducer in tibia of rat and as a stimulator for bone healing and to study the immunohistochemical expression of osteonectin as bone formation markers in experimental and control groups during bone healing. Material and method: : In this study thirty albino male rats , weighting (200-300) gram ,aged (2-3) months ,will be used under control conditions of temperature ,drinking and food consumption. The animals will subject for an
... Show MoreThe objective of this research work is to evaluate the quality of central concrete plant of Al-Rasheed Company by using Six Sigma approach which is a measure of quality that strives for near elimination of defects using the statistical methods to improve outputs that are critical to customers. The fundamental objective of Six Sigma methodology is the implementation of a measurement-based strategy that focuses on process improvement and variation reduction to reach delighting customers, and then suggesting an improvement system to improve the production of concrete in Al-Rasheed State Contracting Construction Company.
A field survey includes two parts (open and close questionnaire) that aimed to get the data and information required f
Baqubah city has grown extremely rapidly. The rate of growth exceeds the growth of services that must grow side by side with the growth of population. There are natural features that affect the growth of Baqubah city such as Dieyala river, Alssariya river, in addition to agricultural areas .All these natural features affect the growth of Baqubah city in the running form being seen . In this research the remote sensing and geographic information system (GIS) techniques are used for monitoring urban expansion and forecasting the probable axes to the growth of the city, and found that the probability of Baqubah growth to east is preferred due to Baqubah growth to the east would never interfere with natural features. Also in this res
... Show MoreBackground: Denture fracture is one of the most common problems encountered by the patients and prosthodontists. The objective of present study was to evaluate the transverse strength of nylon denture base resin repaired by using conventional heat polymerized, autopolymerized and visible light cure {VLC} resins, surface treatment that used for repair and adjustment of insufficient nylon denture bases and in case of addition of artificial teeth. As these corrective procedures are common chair side procedures in dental clinic. Materials and methods: One hundred twenty nylon specimens were prepared by using metal patterns with dimension of (65x10x2.5 mm) length, width, and thickness respectively for transverse strength test while for tensile b
... Show MoreBackground: Using dual-energy X-ray absorptiometry, body fat mass has been determined. The assessment of body fat mass was conducted utilizing dual-energy X-ray absorptiometry analysis of the pelvis and vertebral column. While it is acknowledged that osteoporosis can impact both body fat mass and bone mineral density, the particulars of this relationship currently remain uncertain. Objective: The aim of the present investigation is to assess gender differences in the effects of osteoporosis on the body fat mass of the upper and lower extremities. Method: 170 individuals participated (85 males and 85 females) in this study. Patients who presented with bone discomfort consisted of 40 males and 40 females. In addition, 90 apparently he
... Show MoreThe differential cross section for the Rhodium and Tantalum has been calculated by using the Cross Section Calculations (CSC) in range of energy(1keV-1MeV) . This calculations based on the programming of the Klein-Nashina and Rayleigh Equations. Atomic form factors as well as the coherent functions in Fortran90 language Machine proved very fast an accurate results and the possibility of application of such model to obtain the total coefficient for any elements or compounds.
Cyclophosphamide is chemotherapeutic agent that utilized for the treatment of different malignancies; however its’ used associated with numerous adverse effects. Vitamin B2 and vitamin B12 suggested having myeloprotective effect. This work is designed to investigate the myeloprotective effect of both vitamins against cyclophosphamide induced myelosuppression. One hundred adult rats of both sexes were used in this study. The animals were randomly enrolled into ten groups of 10 rats each. Group I: Control group. Group II: Cyclophosphamide-treated. Group III and Group IV Orally-administered vitamin B2 (10, and 40 mg/kg/day), respectively alone for 7 days. Group V:
... Show MoreEnhancement of heat transfer in the tube heat exchanger is studied experimentally by using discrete twisted tapes. Three different positions were selected for inserting turbulators along tube section (horizontal position by α= 00, inclined position by α= 45 0 and vertical position by α= 900). The space between turbulators was fixed by distributing 5 pieces of these turbulators with pitch ratio PR = (0.44). Also, the factor of constant heat flux was applied as a boundary condition around the tube test section for all experiments of this investigation, while the flow rates were selected as a variable factor (Reynolds number values vary from 5000 to 15000). The results s
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