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.
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This paper presents a sight about the chemical structure deformation of poly (ethylene-co-vinyl acetate) (EVA) samples according to the change ratio of rate constant values. Spectroscopy kinetics fluorescence curves are fitted for two characteristic wavelength domains of fluorescent intensities. The short wavelengths (320-400 nm) domain show spectra overlapping, while at long wavelengths (400-800 nm) domain spectra are arranged in regular for each specific accelerated aging time. The ratio of kinetics rate constant at long wavelengths to kinetics rate constant of short wavelengths is the criterion of the degree chemical structure deformation. Molar extrin
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This paper focused on the stone matrix asphalt (SMA) technology that was developed essentially to guard against rutting distress. For this procedure, fibers play a racy role in stabilizing and preventing the drain down problem caused by the necessity of high binder content coupled with their strengthening effect. A set of specimens with cylindrical and slab shapes were fabricated by inclusions jute, polyester, and carbon fibers. For each type, three contents of 0.25%, 0.5%, and 0.75% by weight of mixture were added by lengths of 5, 7.5, and 10 mm. The prepared mixtures were tested to gain the essential pertained parameters discriminated by the values of drain down, Marshall quotient, rut depth, and dynamic stability. It
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Background: Treatment of malocclusions using removable orthodontic appliances may prepare new stagnant areas susceptible for colonization and retention of Candida species, therefore; the aim of this study was to investigate the effect of upper removable orthodontic appliances on the mucosal Candidal count in group of apparently healthy orthodontic patients. Materials and Methods: Patients enrolled in this study were children aged 8-12 years having upper removable orthodontic appliances. Candidal counts at six mucosal sites were estimated using Imprint Culture method before, 14 and 28 days during orthodontic therapy. Results: Whole mouth and individual mucosal sites for Candidal counts increase significantly during treatment with upper remov
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ABSTRACT Background: Piezosurgery device is a system developed recently to overcome the limitation of the traditional surgical technique in implant site preparation, which use the principle of ultrasonic microvibrations to create precise & selective cut in bone in harmony with the surrounding tissues. The aim of this study was to evaluate the outcomes of implants inserted by ultrasonic implant site preparation protocol (UISP) using piezosurgery device, regarding the survival rate, stability and other related factors, at 16 weeks postoperative follow up period. Materials and Methods: A total of (24) patients, (6) males and (18) females, aged between (19-51) years old, contributed in this study receiving a total of (42) implants, all of these
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The current study aims to compare between the assessments of the Rush model’s parameters to the missing and completed data in various ways of processing the missing data. To achieve the aim of the present study, the researcher followed the following steps: preparing Philip Carter test for the spatial capacity which consists of (20) items on a group of (250) sixth scientific stage students in the directorates of Baghdad Education at Al–Rusafa (1st, 2nd and 3rd) for the academic year (2018-2019). Then, the researcher relied on a single-parameter model to analyze the data. The researcher used Bilog-mg3 model to check the hypotheses, data and match them with the model. In addition
... Show MoreThe study aimed to investigate the effect of different times as follows 0.5, 1.00, 2.00 and 3.00 hrs, type of solvent (acetone, methanol and ethanol) and temperature (~ 25 and 50)ºc on curcumin percentage yield from turmeric rhizomes. The results showed significant differences (p? 0.05) in all variables. The curcumin content which were determined spectrophotometrically ranged between (0.55-2.90) %. The maximum yield was obtained when temperature, time and solvent were 50ºC, 3 hrs and acetone, respectively.
Liposomal amphotericin B (Amph B) has been used effectively to treat leishmaniosis, in spite of its high toxicity appeared in some patients. In our study, Amph B was administered in Leishmania donovani that infected BALB/c male mice using different concentrations to evaluate its efficacy challenge against infection as well as its effect in modulating immunity of the host. We observed that low doses with short duration of Amph B as a therapy regime significantly enhanced the induction of Th1 cytokine (INF-γ), but suppressed Th2 cytokine (IL-10) production. Groups of mice infected with L. donovani and treated with Amph B showed clearly increasing in INF-γ level and reduction in IL-10 level in concentration (3, 4, 5 mg/ml/kg) with best resul
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Solid dispersion (SD) is one of the most widely used methods to resolve issues accompanied by poorly soluble drugs. The present study was carried out to enhance the solubility and dissolution rate of Aceclofenac (ACE), a BCS class II drug with pH-dependent solubility, by the SD method. Effervescent assisted fusion technique (EFSD) using different hydrophilic carriers (mannitol, urea, Soluplus®, poloxamer 188, and poloxamer 407) in the presence of an effervescent base (sodium bicarbonate and citric acid) in different drug: carrier: effervescent base ratio and the conventional fusion technique (FSD) were used to prepare ACE SD. Solubility, dissolution rate, Fourier transformation infrared spectroscopy (FTIR), PowderX-ray diffraction
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CD-nanosponges were prepared by crosslinking B-CD with diphenylcarbonate (DPC) using ultrasound assisted technique. 5-FU was incorporated with NS by freeze drying, and the phase solubility study, complexation efficiency (CE) entrapment efficiency were performed. Also, the particle morphology was studied using SEM and AFM. The in-vitro release of 5-FU from the prepared nanosponges was carried out in 0.1N HCl.
5-FU nanosponges particle size was in the nano size. The optimum formula showed a particle size of (405.46±30) nm, with a polydispersity index (PDI) (0.328±0.002) and a negative zeta potential (-18.75±1.8). Also the drug entrapment efficiency varied with the CD: DPC molar ratio from 15.6 % to 30%. The SEM an
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