Laser etching may be an alternative to acid etching of enamel and dentin. Several characteristics of irradiated dental hard tissues have been considered advantageous, microscopically rough surfaces without demineralization, open dentinal tubules without smear layer production and dentin surface sterilization. The aim of this study is to determine and compare histology the microleakage in class V cavity restored with a light cured composite after conditioning the samples(tooth surface) with 1-acid etching, 2-Q-switched Nd:YAG Laser etching and finally 3- acid and laser etching. Materials and methods: Twenty four non carious human extracted teeth were used in this study. The samples were equally grouped into four groups of six teeth each. A class V cavity was prepared. In group I, tooth surface was etched with a 37% phosphoric acid gel. In group II, the tooth surface was conditioned using a pulsed Nd:YAG Laser alone with a wavelength of 532 nm. The parameters were of pulse energy 60 mJ, pulse repetition rate 6Hz and energy density was 0.48 J/cm2. In group III, the tooth surface was treated with Nd: YAG Laser and then was etched with phosphoric acid. In group IV, the surface was treated with 37% phosphoric acid then irradiated with Nd: YAG Laser; with the same parameters and concentration mentioned in group I and II. The samples immersed in 1% basic fuschin dye to mimic the normal stains in oral cavity and the sections were examined by a stereomicroscope and the readings were scored. Results: The results showed that group IV, in which the surface was treated with 37% phosphoric acid and then irradiated with Nd: YAG Laser) recorded the least microleakage of the four groups, where group III, in which the tooth surface was treated with Nd: YAG Laser and then was etched with phosphoric acid)recorded reasonable results better than group I (group I tooth surface was etched with a 37% phosphoric acid gel) or group II , in which the tooth surface was conditioned using a pulsed Nd:YAG Laser alone) Conclusion: The use of Q-switched Nd:YAG laser in etching the tooth surface was so effective that it can be used in treating or conditioning the tooth surface to enhance bonding and the best parameters among the tested samples were pulse energy of 60mJ, pulse repetition rate of 6Hz and energy density 0.48 J/cm2.
The Andoluosian literatures has been captured my mind, and had a very
pure and great place in my spirit, which is remembering me the roots of
genuine Arabic civilization spread during eight century in endoluos region.
also the Arabic creation which is moved from east to far way land in that
ages. And very clearly appearance tremendous men interested in science and
all kind of literature and arts especially in poetry, no one who has taste and
minimum knowledge can denied the effect of indoluosan prosperity among
readers. So for that reason I work very hard to choose a very famous poet his
nick name (Al-Ramadee) he is Youseif Bin Haroon born in the first decade
of the 4TH hijri (Islamic Calendar), died in (403H).
ارتبط الانسان بالطبيعة بأشكالها المختلفة ارتباطا وثيقا ، فهي تمثل الحاضنة له بمجالات حياته كلها، فما كان من الأدباء الا أن يجعلوها في كثير من الأحيان مادة لأدبهم وأرضية خصبة لنتاجهم، فتمظهرت بصورها المختلفة وحاجة الانسان لها وخيرها وشرها في الأدب على مدى التاريخ، والعرب شأنهم شأن غيرهم من الأمم فمنذ عصر ما قبل الاسلام كانت الطبيعة منفذا مهما وملجأ للشعراء في انتاج الأدب وابداعه وإلى يومنا هذا، ونحن إذ نتحد
... Show MoreThe importance the youth because they are the fundamental basis of the development process so to be an emphasis on their active participation in community building . When there is community participation the democratization . Will tazzfa community because the process of community participation and develop the capacity to carry on almsoulin among young people and will lead to culture of self confidence and alhawwar walaklauah . Beactivted and community participation for young people through several channels . Family , school , media and civil society organization as we discussed in the research factrstnat hinder community participation of youth in development . The most important factors that hinder participating based on patriarc
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In this paper, a method for hiding cipher text in an image file is introduced . The
proposed method is to hide the cipher text message in the frequency domain of the image.
This method contained two phases: the first is embedding phase and the second is extraction
phase. In the embedding phase the image is transformed from time domain to frequency
domain using discrete wavelet decomposition technique (Haar). The text message encrypted
using RSA algorithm; then Least Significant Bit (LSB) algorithm used to hide secret message
in high frequency. The proposed method is tested in different images and showed success in
hiding information according to the Peak Signal to Noise Ratio (PSNR) measure of the the
original ima
وفي الحقيقة وأنا أكتب عن الفكر العمراني عند اليعقوبي وقفت وقفات طويلة أردت منها أن أحدد المجال الذي أبدع فيه اليعقوبي لكي أوسم موضوع بحثي، كأن أقول عنه الجغرافي أو مهندس أو رحالة أو أديب، لكني وجدته جغرافياً طبيعياً وبشرياً ومهندس بناءً عارفاً بمواد البناء وهندسة البناء وهندسة المساحة والطرق والجسور والهندسة المعمارية، لذا وجدته موسوعة لكل ما كان في عصره من العلوم، فضلاً عن كونه مؤرخاً، له مؤلفة المشهور ((
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