Introduction: This study was performed to compare the effect of Fractional CO2 laser or Q switched Nd:YAG laser of surface treatment on the shear bond strength of zirconia-porcelain interface. Methods: Fractional CO2 laser at 30 W, 2 ms, time interval 1 ms, distance between spots 0.3 mm, and number of scans is (4) or Q switched Nd:YAG laser at 30 J/mm2 and 10 Hz were used to assess the shear bond strength of zirconia to porcelain. Pre-sintered zirconia specimens were divided into three groups (n = 10) according to the surface treatment technique used: (a) untreated (Control) group; (b) CO2 group; (c) Nd:YAG group. All samples were then sintered and veneered with porcelain according to the manufacturer’s instructions. Surface morphology was examined using a light microscope, the surface roughness test was done by the atomic force microscope (AFM), and the shear bond strength (SBS) test was done by a universal testing machine. After debonding following shear bond test, zirconia surfaces were examined under a light microscope to determine their fracture mode. Results: The Results of this study showed that the lowest SBS was recorded in the control group, and the highest SBS recorded in the Fractional CO2 group, followed by the Q switched Nd:YAG laser group, as well as an increase in surface roughness and change in the morphology and mode of failure in the experimental groups . Conclusion: This study shows that Fractional CO2 laser and Q switched Nd:YAG laser treatments significantly increase the bond strength than untreated zirconia .
This work introduces a new electrode geometry for making holes with high aspect ratios on AISI 304 using an electrical discharge drilling (EDD) process. In addition to commercially available cylindrical hollow electrodes, an elliptical electrode geometry has been designed, manufactured, and implemented. The principal aim was to improve the removal of debris formed during the erosion process that adversely affects the aspect ratio, dimensional accuracy, and surface integrity. The results were compared and discussed to evaluate the effectiveness of electrode geometry on the machining performance of EDD process with respect to the material removal rate (MRR,) the electrode wear rate (EWR), and the tool wear ratio (TWR). Dimensional features an
... Show MoreIn the present study, activated carbon supported metal oxides was prepared for thiophene removal from model fuel (Thiophene in n-hexane) using adsorptive desulfurization technique. Commercial activated carbon was loaded individually with copper oxide in the form of Cu2O/AC. A comparison of the kinetic and isotherm models of the sorption of thiophene from model fuel was made at different operating conditions including adsorbent dose, initial thiophene concentration and contact time. Various adsorption rate constants and isotherm parameters were calculated. Results indicated that the desulfurization was enhanced when copper was loaded onto activated carbon surface. The highest desulfurization percent for Cu2O/AC and o
... Show MoreThe university Service employee is considered one of the categories of public employees, However, The academic and administrative tasks duties that undertakes have made him a special importance and a distinguished legal status, Therefore, we find That the Iraqi legislatures assigned this category a special Law, it is the university Service law No (23) of 2008 as amended who dealt with some aspects related to serving this category, such as duties, right, condition for appointment and award of academic titles, and financial allocation, such as university service allocation, academic title allocations, and some other Provisions leaving other matters to the general service laws and employee discipline, among the matters that the legislator negl
... Show MoreBackground: Heterocyclic compounds and its derivatives have biological activities and used as analgesic, anti-helminthic, antituberculer, antifungal, antiviral, anticancer and inhibitor of some enzymes. Oxazepine (benzodiazepine) derivative used in relief of psychoneuroses characterized by anxiety and tension. Alkaline phosphatase (ALP) hydrolyzes phosphate monoesters, while Lactate dehydrogenase (LDH) catalyses oxidation of L-lactate to pyruvate utilizing NAD+Objective: The study was carried out to know of the impact of 1,3-oxazepine derivative on the ALP and LDH enzyme activity on human serum in vitro.Methods: The study included the effect of synthesized 1,3-oxazepine divertive [(Z)-3-(5-mercapto-1-3,4-Thiadizol-2-yl)-2-(4-nitroph
... Show MoreSurface water samples from different locations within Tigris River's boundaries in Baghdad city have been analyzed for drinking purposes. Correlation coefficients among different parameters were determined. An attempt has been made to develop linear regression equations to predict the concentration of water quality constituents having significant correlation coefficients with electrical conductivity (EC). This study aims to find five regression models produced and validated using electrical conductivity as a predictor to predict total hardness (TH), calcium (Ca), chloride (Cl), sulfate (SO4), and total dissolved solids (TDS). The five models showed good/excellent prediction ability of the parameters mentioned above, which is a very
... Show MoreThe present work determines the particle size based only on the number of tracks detected in a cluster created by a hot particle on the CR-39 solid state nuclear track detector and depending on the exposure time. The mathematical model of the cross section developed here gives the relationship between alpha particle emitting from the (n, α) reaction and the number of tracks created and distribution of tracks created on the surface of the track detector. In an experiment performed during this work, disc of boron compound (boric acid or sodium tetraborate) of different weights were prepared and exposed to thermal neutron from the source. Chemical etching is processes of path formation in the detector, during which a suitable etching solut
... Show MoreBackground: The relation between insulin resistance ,leptin levels and other hormones in women with polycystic ovary syndrome(PCOS) is still controversial.Metformin therapy is proved effective in reducing insulin resistance and also in some studies it was seen to be effective in reducing leptin levels.
Al- Kindy Col Med J 2012 ; Vol .8 No. (2) p: 65
Objective: to study the effect of metformin on reducing leptin levels and enhancing ovulation in PCOS women.
Methods:metformin 500mg 3 times daily for 3 months was was given to 36 women
with proved PCOS, in addition to that, other parameters were included.
Results:28 women out of 36(77.78%) showed an evidence of ovulation ovulation after 3 months of metformin therapy(p<0.01)
Background: There is a clear debate about the role of bad oral habits (thumb-sucking and biting nails) and on oral health and the state of the dental caries, but there is no doubt that continuing these bad habits until advanced ages will lead to deep and difficult problems to solve. Objective: The purpose of study was to evaluate the effect of bad habits, include finger sucking and nail biting on dental caries among children aged from 6 to 10 years old. Subjects and methods: In Al-Hilla city, Iraq, a comparative study was conducted in which (200) primary school students aged between 6 to10 years old were involved. A questionnaire filled out by their parents was used to gather information related to the bad oral habit, and then all the stude
... Show More