Background: The irradiation of teeth with a laser results in an interaction between the light and the biological constituents of the dental hard substance, which is converted directly into heat.This thermal effect is the cause of the structural and chemical enamel changes.The combined treatment of topical fluoride agent with laser may increase fluoride uptake, and reduce progression of caries-like lesions. The aim of this study was to measure the uptake of the acidulated phosphate fluoride and sodium fluoride to the buccal and lingual caries-like lesion enamel surfaces before and after irradiated by Nd-YAG laser in comparison with matching control group. Materials and methods: The sample consisted of 30 human healthy upper premolar teeth which were stored in 0.1% thymol solution after extracted. Every tooth divided into: buccal and lingual specimen, each specimen has a rectangular window which was divided to right and left halves (120 specimens). The sample was divided into 2groups (60 specimens) for buccal surface, and the same for lingual surface. The caries-like lesion was formed for all groups except control (1) each group treated with either acidulated phosphate fluoride 1.23% or sodium fluoride 2%, (30 specimens) which contain other subgroups, these are: (10 specimens) one half treated with fluoride agent only and another half as control (first group as control (1) without caries-like lesion, and the second group control (2) with caries-like lesion, then de-ionized water only). (10 specimens) treated with fluoride agent then irradiated by Nd-YAG laser; one half with program (1) (short pulse), andanother with program (2) (long pulse). (10 specimens) irradiated by Nd-YAG laser; one half with program (1) and another with program (2) then treated with fluoride agent. The specimens of enamel were sectioned and the fluoride uptake was determined with using fluoride sensitive electrode. Results: There was a significant difference between the buccal and lingual enamel surfaces regarding the fluoride uptake in sound tooth, while a non- significant difference was observed after artificial caries-like lesion formation. Conclusion: Irradiation of Nd-YAG laser program (1) to the buccal and lingual caries-like lesion surfaces of enamel before application of fluoride agents (APF, NaF) was significantly increase fluoride uptake than that of using laser after the application of fluoride agent, as well as from using laser of program (2) after and before the application of fluoride agent, and from using fluoride agent alone in the buccal and lingual surfaces.
This work has been done with using of epoxy resin mixed with Granite powder were weighted by percent volume (5,10,15, and 20)%and then mixed with epoxy polymer to compose polymer composite. Hand lay-up technique is used in fabrication of the composite samples. Hardness test was carried out for the proper samples in both normal condition and after immersion in HCL (1 M and 2 M) solutions for periods ranging up to 10 weeks. After comparing the results between the polymer and their composite, the hardness increased with increasing Granite weight percent, it was found that Hardness were greater for the composites before immersion compared with their values after immersion.
The effect of the concentration of the colloidal nanomaterial on their optical limiting behavior is reported in this paper. The colloids of sliver nanoparticles in deionized water were chemically prepared for the two concentrations (31 ppm and 11ppm). Two cw lasers (473 nm Blue DPSS laser and 532 nm Nd:YAG laser) are used to compare the optical limiting performance for the samples. UV–visible spectrophotometer, transmission electron microscope (TEM) and Fourier Transformation Infrared Spectrometer (FTIR) were used to obtain the characteristics of the sample. The nonlinear refractive index was calculated to be in the order of 10-9 cm2/W. The results demonstrate that the observed limiting response is significant for 532nm. In addition, t
... Show MoreIn this work, the effect of vortex shedding on the solar collector performance of the parabolic trough solar collector (PTSC) was estimated experimentally. The effect of structure oscillations due to wind vortex shedding on solar collector performance degradation was estimated. The performance of PTSC is evaluated by using the useful heat gain and the thermal instantaneous efficiency. Experimental work to simulate the vortex shedding excitation was done. The useful heat gain and the thermal efficiency of the parabolic trough collector were calculated from experimental measurements with and without vortex loading. The prototype of the collector was fabricated for this purpose. The effect of vortex shedding at different operation condition
... Show MoreThe purpose of this study is designate quenching and tempering heat treatment by using Taguchi technique to determine optimal factors of heat treatment (austenitizing temperature, percentage of nanoparticles, type of base media, nanoparticles type and soaking time) for increasing hardness, wear rate and impact energy properties of 420 martensitic stainless steel. An (L18) orthogonal array was chosen for the design of experiment. The optimum process parameters were determined by using signal-to-noise ratio (larger is better) criterion for hardness and impact energy while (Smaller is better) criterion was for the wear rate. The importance levels of process parameters that effect on hardness, wear rate and impact energy propertie
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The objective of this research was to investigate the effect of replacing fat(shortening) with different percentages of tahena on the quality properties (physiochemical and sensory ) of shortened cake.The percentages of moisture,protein ,fat and ash of cake increased significantly(p<0.05) as the replacement was increased .The highest increase percentages were 10,48,5,and 90 %,respectivly, at 100% replacement .Carbohydrate,however,decreased by 10%at 100% replacement .these findings may indicate improvement of cake nutritional value.Standing height,as an indicator of cake volume, also increased significantly by 4% at the 50% replacement then it decreased by 4% 100% replacement level. Basic formula (control) has signific
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Unsaturated soil can raise many geotechnical problems upon wetting and drying resulting in swelling upon wetting and collapsing (shrinkage) in drying and changing in the soil shear strength. The classical principles of saturated soil are often not suitable in explaining these phenomena. In this study, expansive soil (bentonite and sand) were tested in different water contents and dry unit weight chosen from the compaction curve to examine the effect of water content change on soil properties (swelling pressure, expansion index, shear strength (soil cohesion) and soil suction by the filter paper method). The physical properties of these soils were studied by conducting series of tests in laboratory. Fitting methods
... Show MoreA field trial was conducted in Experimental Station of The Field Crops Department – College Of Agriculture In Abu Ghraib, University of Baghdad to assess the effect of sulphur applications and the time after application on pH and EC of soil sample solutions ,and on the growth and yield of rape seed (Brassica napus L.)A split plot design was used with four replications , The main plot included four sulphur applications levels (0,2000,3000,4000Kg S/ha) the sub plot were the time after application (0,1,2,and 3 moths) .Sulphur application significantly decreased soil pH value ,although that decrease reached minimum parameter after two months from application date .Rather increment of sulphur application level significantly raised soil EC val
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Background: Vibration decreases the viscosity of composite, making it flow and readily fit the walls of the cavity. This study is initiated to see how this improved adaptation of the composite resin to the cavity walls will affect microleakage using different curing modes
Materials and methods: Standard Class V cavities were prepared on the buccal surface of sixty extracted premolars. Teeth were randomly assigned into two groups (n=30) according to the composite condensation (vibration and conventional) technique, then subdivided into three subgroups (n=10) according to light curing modes (LED-Ramp, LED-Fast and Halogen Continuous modes). Cavities were etched and bonded with Single Bond Universal
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Nisoldipine (NSD) is a dihydropyridine class of calcium channel blockers used for hypertension treatment, it belongs to class II BCS (low solubility with high permeability), its absolute bioavailability is only 5% due to presystemic metabolism in the gut wall. It is also a substrate for a CYP3A and P-gp. Bilosomes are lipid bilayer vesicles incorporating bile salts in their walls to prevent degredation by GIT bile salts. The aim of this study is to prepare nisoldipine bilosomes as vesicular carrier and assess the effect of different formulation variables such as type of surfactant, amount of cholesterol, surfactant and sonication time on particle size, entrapment efficiency and poly dispersity index of the prepared bilos
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