Background: This study was formulated to compare the effect of 5%hydrofluoric acid in comparison to 37%phosphoric acid with and without the application of silane on bond strength of composite to porcelain. Materials and Methods: Specimen preparation was divided in to two phases, metal-disks fabrication (8mm-diameter and 4mm-thickness) and ceramic veneering. Thirty two specimens were prepared, sandblasted with 50 μm aluminum oxide, and divided into four groups of eight samples. Groups I and III were etched with 37%phosphoric acid while groups II and IV were etched with 5%hydrofluoric acid; and groups I and II were silaneted while groups III and IV were not. Heliobond, and resin composite were applied to each specimen using a plastic transparent split mold (4mm- diameter and 4mm-height). Specimens were stored in distilled water for 24 hours then thermocycled for 100 cycles. Shear bond strength was determined by a Zwick universal machine at a cross-head speed 5 mm/minute. Results: Mean shear bond strength values were 21.02(group I), 23.31(group II), 4.00(group III), and 18.60(group IV). Paired-t revealed that specimens treated with 5%hydrofluoric acid were significantly higher than those treated with 37%phosphoric acid regardless the use of silane. The use of silane dramatically enhanced the bond strength of composite resin to porcelain for both acids. All specimens treated with 37%phosphoric acid without silane showed adhesive failure, while those treated with 5%hydrofluoric acid showed mostly cohesive failure within ceramic. Conclusion: Silane improved the shear bond strength of composite to ceramic, and hydrofluoric acid performed greater bond strength compared to phosphoric acid.
Jurisprudence purposes Anwash and his importance
In this work a Nd:YVO4 thin disc laser setup is designed and fabricated. The disk laser system
is designed to be compact. The laser crystal was pumped by a 808 nm diode laser. The effect of input
current and pulse frequency on the output energy at pulse operation mode, and the effect of the input
current on the output power at CW mode operation are tested. At the pulsed mode, the output energy
increased linearly with the input current and decreased with pulse frequency. The threshold current
increased with increasing pulse frequency increasing. The maximum output energy from the thin disc
laser was 0.98 μJ at 1.3 kHz frequency, with 0.49A. A minimum threshold current for CW mode of
operation. The maximum outpu
The goal of this research is to introduce the concepts of Large-coessential submodule and Large-coclosed submodule, for which some properties are also considered. Let M be an R-module and K, N are submodules of M such that , then K is said to be Large-coessential submodule, if . A submodule N of M is called Large-coclosed submodule, if K is Large-coessential submodule of N in M, for some submodule K of N, implies that .
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Abstract Rationality and freedom are fundamental elements of Western modernity. Although modern and contemporary Islamic thought has established its intellectual foundations on the fundamentals of intellectual thought that are at the core of its Islamic intellectual system, at the same time many of its intellectual products have been a response In spite of the fact that this Islamic intellectual response stands out from Western modernity as a negation or a positive attitude. The Islamic intellectual response differed in determining its position on Western modernity, depending on the nature of the historical stage that was The Islamic nation, as well as the nature of the challenge posed by Western civilization to other nations and other c
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Despite the history of Baghdad city extends into a long history, most of the contemporary buildings of Baghdad have been shaped in the era of modernity. Furthermore, most of the buildings of modernity in Baghdad are types of modernity buildings in Iraq as a whole, and due to all the joints of change and development are taking place in Iraq starts from Baghdad. Accordingly, all selected buildings, which would be presented as case studies of modernity will be exclusively in Baghdad. Although the importance of this significant modernist product, which represents the identity of Baghdad, which should be preserved by the renewal and preservation policies, the problem of research was emerged as follow: new fin
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E-learning seeks to create an interactive learning environment between the teacher and the learner through electronic media conveying in more than one direction, regardless of how the environment and its variables are identified. It also develops skills necessary to deal with technology in order to be able to take into account the individual differences between them and helps e-learning teacher and learner to achieve the goals set in advance and identify educational objectives in a clear manner. The research aims to identify e-learning in its benefits and management systems. It has three sections dealt with in the current research. Chapter II concentrates on the research Methodology, which consisted of three sections: The first s
... Show MoreBackground: Fetal macrosomia represent a
continuing challenge in obstetrics and increasing in
it's occurrence as well as it is associated with maternal
and perinatal complications.
Objective : To determine the maternal and perinatal
outcome related to fetal macrosomia.
Design: A prospective case control study.
Patients and methods) :10th March-31st May, 2006
A prospective case control study had done over the
period from 10th March to 31st May, 2006 in Al-Batool
maternity teaching hospital in Mosul city .The study
group consisted from 633 singleton alive newborns
with gestational age ≥37weeks weighing 4000 grams
and heavier and mothers of these newborns compared
with control group which consiste
This paper focuses on the most important element of scientific research: the research problem which is confined to the concept of concern or concern surrounding the researcher about any event or phenomenon or issue paper and need to be studied and addressed in order to find solutions for them, to influence the most scientific research steps from asking questions and formulating hypotheses, to employ suitable methods and tools to choose the research and sample community, to employ measurement and analysis tools. This problem calls for a great effort by the researcher intellectually or materially to develop solutions.
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Melatonin, a hormone synthesized mainly by the pineal gland, has been found in extra-pineal organs as well. It’s known as an organizer of circadian rhythms and more recently as an anti-oxidant. In addition to its role in maintaining immunity, pathophysiology of cardiovascular and neurological diseases, and as an anti-cancer agent, evidence has demonstrated that melatonin exerts a positive impact on male and female fertility primarily through oxygen scavenging effects. In In Vitro Fertilization (IVF) programs, supplementation of melatonin may be associated with better outcomes in terms of sperm quality, oocyte quality, embryo quality and pregnancy rates. This review summarizes various actions of melatonin on the body focusing on male an
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