Background: The bond strength of root canal sealers to dentin was important for maintaining the integrity of the seal in root canal filling in both static and dynamic situations. In a static situation, it should eliminate any space that allowed the percolation of fluids between the filling and the wall while in a dynamic situation; it was needed to resist dislodgement of the filling during subsequent manipulation. Materials and Methods: Forty mandibular premolars were selected for this study. All canals were instrumented using ProTaper rotary instruments. Instrumentation was done with copious irrigation of 5.25% sodium hypochlorite. Roots were randomly divided into four groups according to the type of cleaning and method of root canal irrigation (ten teeth for each group): Group A. The root canals were irrigated with 5 ml of 17% of EDTA for 1 minute and 5 ml of 5.25% NaOCl. Group B. Cleaning with waterlase laser. Group C. The root canals were irrigated with 5 ml of 5mg/ml of siwak (Salvadora persica) extract for one minute. Group D. The root canals were irrigated with 5 ml of 5% of green tea (camellia sinensis) extract for one minute. All groups were rinsed with distilled water and then obturated with cold lateral condensation technique and i Root sp sealer (Bioceramic sealer, the roots then stored in moist environment at 37°C for one week. Three horizontal sections were prepared at a thickness of 1 mm ±0.1 in the apical, middle and coronal parts of each root. The test specimens were subjected to the push-out test method using a Universal Test Machine that carried 1-mm, 0.5- mm and 0.3-mm plungers for coronal, middle and apical specimens, respectively. The loading speed was 0.5 mm/ min. The computer showed the higher bond force before dislodgment of the filling material. These forces were divided by the surface area to obtain the bond strength in MPa. Results: In all groups the mean value of push-out strength was greatest in apical area and least in coronal area and the middle area was in between, except in Waterlase the middle area showed the least mean push-out strength. Conclusion: Herbal extracts used in this study (Siwak and green tea) can be used safely as an intra-canal irrigant for smear layer removal with efficiency that is comparable with conventional synthetic materials (EDTA) and more complicated methods (Waterlase).
Objective: The present study investigates whether the exposure to low-power diode laser induces denaturation in red blood cell (RBC) membrane protein composition, and determines the irradiation time for when denaturation of membrane protein process begins. Background: A low-energy laser has been used extensively in medical applications. Several studies indicated significant positive effects of laser therapy on biological systems. In contrast, other studies reported that laser induced unwanted changes in cell structure and biological systems. The present work studied the effect of irradiation time of low-power diode laser on the structure of membrane proteins of human RBCs. Materials and methods: The RBC suspension was divided into five equa
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Extract from cell culture of medicinal plant like Nigella sativa have been assessed for its cytotoxic properties. Thymol is likely responsible for the theraputic effects of Nigella sativa leaf callus extract. In this short study the inhibitory effect of Nigella sativa leaf callus extract (Thymol) has been studied on Human Lorgnx Epidrmoid Carcinoma (Hep-2) cell line during different exposure period of time (24, 48 and 72 hrs.) using different concentration of the extract (1000, 500, 400, 300, 200 and 100 µg/ml). The optical density of the Hep-2 cells has been readed on 492 nm wave length. Thymol –induced cytotoxicity was (500 µg/ml) which inhibit cell growing compared to the control and this
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The study dosage ethanol in the total content of acid sialic TC and acid sialic associated fat (LBSA) in blood serum and congener brain Dkor Jerd eggs study included dosage 20 animals of male rat Ald ethanol daily for a period of four weeks and concentrations 20% and 30%, 40%, 50% and size of dose 5mlThe results of the study showed that levels of TSA homogeneous in the brain and blood serum significantly reduced Ankhvaza
Back ground: In the present study Pinealoctomy
was used to study the sympathetic innervations of
the pineal gland by the superior cervical ganglion
(SCG) of the albino rat.
Objective: Following Pinealoctomy, it is
expected to observe the Chromatolysis reaction in
some neurons of the SCG if they were to innervate
the pineal gland (i.e. retrograde Chromatolysis
changes).
Methods: Fifty albino rats were used in this study,
Pinealoctomy was done, then after a different time
interval ganglionectomy was done, in order to
study the Chromatolysis in their cell body.
Result: The present study has demonstrated that
the most obvious Chromatolysis reaction in the
neurons which innervate the pineal gland a
Six proposed simply supported high strength-steel fiber reinforced concrete (HS-SFRC) beams reinforced with FRP (fiber reinforced polymer) rebars were numerically tested by finite element method using ABAQUS software to investigate their behavior under the flexural failure. The beams were divided into two groups depending on their cross sectional shape. Group A consisted of four trapezoidal beams with dimensions of (height 200 mm, top width 250 mm, and bottom width 125 mm), while group B consisted of two rectangular beams with dimensions of (125 ×200) mm. All specimens have same total length of 1500 mm, and they were also considered to be made of same high strength concrete designed material with 1% volume fraction of steel fiber.
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This study aims to investigate the behavior and strength of self-compacted ferrocement slabs under punching shear load. Experimental results of thirteen square ferrocement slabs of 500×500 mm simply supported on all edges are presented. The main parameters investigated include the volume fraction of reinforcement, slab thickness and size of load-bearing plate. The load deflection and cracking characteristics of the tested slabs are studied and compared. The test results showed that the volume fraction of wire mesh has significant effect on both ultimate load and displacement. The increase of slab thickness leads to decrease in deflection values and increase in stiffness of slabs. Both ductility and stiffness increase as the
... Show MoreThis paper presents the application of nonlinear finite element models in the analysis of dapped-ends pre-stressed reinforced concrete girders under static loading by using ANSYS software. The girder dimensions are (4.90 m span, 0.40 m depth, 0.20 m width, 0.20 m nib depth, and 0.10 m nib length) and the parameters considered in this research are the pre-stress effect, and strand profile (straight and draped).
The numerical results are compared with the experimental results of the same girders. The comparisons are carried out in terms of initial prestress effect, load- deflection curve, and failure load. Good agreement was obtained between the analytical and experimental results. Even that, the
... Show MoreThe present work is concerned with the investigation of the behavior and ultimate capacity of axially loaded reinforced concrete columns in presence of transverse openings under axial load plus uniaxial bending. The experimental program includes testing of twenty reinforced concrete columns (150 × 150 × 700 mm) under concentric and eccentric load. Parameters considered include opening size, load eccentricity and influence of the direction of load eccentricity with respect to the longitudinal axis of the opening. Experimental results are discussed based on load – lateral mid height deflection curves, load – longitudinal shortening behavior, ultimate load and failure modes. It is found that when the direction of load
... Show MoreThis paper presents the application of nonlinear finite element models in the analysis of dappedends pre-stressed reinforced concrete girders under static loading by using ANSYS software. The girder dimensions are (4.90 m span, 0.40 m depth, 0.20 m width, 0.20 m nib depth, and 0.10 m nib length) and the parameters considered in this research are the pre-stress effect, and strand profile (straight and draped). The numerical results are compared with the experimental results of the same girders. The comparisons are carried out in terms of initial prestress effect, load- deflection curve, and failure load. Good agreement was obtained between the analytical and experimental results. Even that, the numerical model was stiffer than the experiment
... Show MoreThe electrical properties of pure NiO and NiO:Au Films which are
deposited on glass substrate with various dopant concentrations
(1wt.%, 2wt%, 3wt.% and 4wt.%) at room temperature 450 Co
annealing temperature will be presented. The results of the hall effect
showed that all the films were p-type. The Hall mobility decreases
while both carrier concentration and conductivity increases with the
increasing of annealing temperatures and doping percentage, Thus,
indicating the behavior of semiconductor, and also the D.C
conductivity from which the activation energy decrease with the
doping concentration increase and transport mechanism of the charge
carriers can be estimated.
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