It is found that hypersensitive teeth have a larger number and wider patent tubules than those of non-sensitive teeth. Objective: The aim of this study is to compare between the effects of diode laser at different power densities, with and without sodium fluoride on the sealing of exposed dentinal tubules and dentin permeability. Materials and methods: 118 teeth were used. Samples were divided into three major groups. The first consisted of 100 teeth used for permeability test. The second consisted of 16 teeth for measuring external surface temperature elevation while irradiation. The third, in turn, consisted of one pair of teeth observed under SEM for dentine surface morphology analysis. Results: For dentin permeability measurement, the results revealed a highly significant difference between the control group and 2, 3 W with varnish groups. For the external surface temperature elevation, the results revealed that temperature rise, for both laser alone and with varnish groups, was between (67-97.9 ∘C) at 1.6, 2 W. SEM analysis revealed that approximately optimum sealing of tubules occurred in 2W with the varnish group. Conclusions: The combined application of 940 nm diode laser at 2W with 809.7 W/cm² power densities, with sodium fluoride white varnish show a significant improvement in their effects on dentin permeability reduction as compared to each treatment alone.
The current study examined the impact of using PowerPoint presentation on EFL student’s attendance, achievement and engagement. To achieve the aim of this study, three null hypotheses have been posed as follows: There is no statistically significant difference between the mean score of the experimental group attendance and that of the control one; there is no statistically significant difference between the mean score of the experimental group achievement and that of the control one, and there is no statistically significant difference between the mean score of the experimental group engagement and that of the control one. To verify a hypothesis, a sample of sixty students is chosen randomly from the third year, department of English,
... Show MoreIs the subject of Facebook of more topics that aroused interest and that it provides the features and services that allows users to direct communication and interaction and dialogue with others, and deals with the subject of research the use of Facebook and its effects left by the social relations, as the field study was conducted on a sample of 130 students from students Baghdad University of males and females in the Faculty of Political Science and Agriculture, Science and Education, Girls, and limited the sample to Facebook users exclusively to test the study hypotheses and relationships connectivity, and the results revealed the presence of a significant impact of Facebook in th
... Show MoreGrabisch and Labreuche have recently proposed a generalization of capacities, called the bi-capacities. Recently, a new approach for studying bi-capacities through introducing a notion of ternary-element sets proposed by the author. In this paper, we propose many results such as bipolar Mobius transform, importance index, and interaction index of bi-capacities based on our approach.
Partial shading is one of the problems that affects the power production and the efficiency of photovoltaic module. A series of experimental work have been done of partial shading of monocrystalline PV module; 50W, Isc: 3.1A, Voc: 22V with 36 cells in series is achieved. Non-linear power output responses of the module are observed by applying various cases of partial shading (vertical and horizontal shading of solar cells in the module). Shading a single cell (corner cell) has the greatest impact on output energy. Horizontal shading or vertical shading reduced the power from 41W to 18W at constant solar radiation 1000W/m2 and steady state condition. Vertical blocking a column
... Show MoreIn this work, analytical study for simulating a Fabry-Perot bistable etalon (F-P cavity) filled with a dispersive optimized nonlinear optical material (Kerr type) such as semiconductors Indium Antimonide (InSb). Because of a trade off between the etalon finesse values and driving terms, an optimization procedures have been done on the InSb etalon/CO laser parameters, using critical switching irradiance (Ic) via simulation systems of optimization procedures of optical cavity. in order to achieve the minimum switching power and faster switching time, the optimization parameters of the finesse values and driving terms on optical bistability and switching dynamics must be studied.
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So I present in the hands of the honorable reader what God Almighty has made easy for me in terms of what I dealt with in the rule (the principle of permissive things) and what branches from it and what is related to it.
This research was divided into an introduction, a preface, three demands, and a conclusion.
The preamble is to explain the meaning of the rule in language and terminology and the definition of the legal rule and what is related to it. The first requirement is to explain the rule that we have in our hands and the words related to its text - and is it a fundamentalist or jurisprudential rule? .
As for the second requirement - in the difference of scholars and their opinions in whether the origin of things is permi
The synthesis and bioactivity of zinc oxide nanoparticles has been extensively studied. The antibacterial activity of different antibiotics individually (ceftriaxone (C), chloramphenicol (CRO), penicillin (P) and amoxicillin (Ax)) and Zinc oxide nanoparticles (60μg/ml) in combination with the previously mentioned antibiotics has been demonstrated in the present study by using the disk diffusion assay method. The results showed a synergistic effect between Zinc oxide nanoparticles (ZnO NPs) and both Ax and P for most of the studied Gram-positive isolates (Staphylococcus aureus1, Staphylococcus aureus2, Staphylococcus epidermidis1, Staphylococcus epidermidis2, Enterococcus faecalis1, Enterococcus faecalis2 ) and between ZnO NPs and both C
... Show MoreThis work aims to investigate the dependence of gravitational lensing properties on the lens redshift and source redshift.
The angular diameter distance hereafter referred to as ADD has been determined using two different numerical integral methods, Simpson's rule, and definite integral methods. Both of those two methods gave identical results. In addition, observational data of gravitational Lensing systems have been used to find the most probable value of lens redshift and source redshift. The result showed that the lens redshift and source redshift are more likely to occur in the ranges of zL=0.2-0.6 and zS=1-3, respectively.
Einstein radius and the critical surface mass density
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The structural, optical properties of copper oxide thin films ( CuO) thin films which have been prepared by thermal oxidation with exist air once and oxygen another have been studied. Structural analysis results of Cu thin films demonstrate that the single phase of Cu with high a crystalline structure with a preferred orientation (111). X-ray diffraction results confirm the formation of pure (CuO) phase in both methods of preparation. The optical constant are investigated and calculated such as absorption coefficient, refractive index, extinction coefficient and the dielectric constants for the wavelengths in the range (300-1100) nm.
Throughout the centuries, several incidents of mercury toxicity have been reported. Mercury is found in many industries such as battery, thermometer and barometer manufacturing, in the agricultural industry is used in fungicides and in medicine, mercury is used in dental amalgams. An important mechanism involved in cellular injury is induced by exposure to different forms of mercury involves in the induction of oxidative stress. This study was conducted on non-smoker, male working in a chloroalkali plant for different periods, all workers were not suffering from chronic disease. Healthy non-smoker males that are not exposed, matched age were used as controls(C), workers aged (22-61) years, they were di
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