The purpose of this work was to study the effects of the Nd:YAG laser on exposed dentinal
tubules of human extracted teeth using a scanning electron microscope (SEM). Eighty 2.5mm-thick
slices were cut at the cementoenamel junction from 20 extracted human teeth with an electric saw. A
diamond bur was used to remove the cementum layer to expose the dentinal tubules. Each slice was
sectioned into four equal quadrants and the specimens were randomly divided into four groups (A to D ).
Groups B to D were lased for 2 mins using an Nd:YAG laser at 6 pulses per second at energy outputs of
80 , 100 and 120 mJ. Group A served as control. Under SEM observation, nonlased specimens showed
numerous exposed dentinal tubules. SEM observation revealed that application of Nd:YAG laser at
energy output of 80 mJ may cause melting of dentin and partial closure of exposed dentinal tubules
without dentin surface cracking. But when the energy output raised to 100 and 120 mJ more sealing of
dentinal tubules occurs. Heat generation occurred in all lased groups but the amount of temperature
increase was within the permissible limits(less than 5.5⁰C). The measured sealing depths were from 3-
5μm for groups B-D and the width of the created groove was 30μm in all lased groups. In conclusion
lasing with nanosecond Nd:YAG with a wavelength of 1064nm at 120mJ with 6Hz for 2 minutes (group
D) shows the efficient laser parameters for complete sealing of exposed dentinal tubules without
temperature increase to the damaging level of the pulp tissue.
The Local and Global Corporations are suffering of managerial and financial corruption phenomena, which leads them to loss and bankruptcy. So, it is necessary to search for tools which help prevent phenomena like this, and one of these tools is (corporate governance) which represent controlling tool that contribute in reducing corruption. this study aims at modifying (corporate governance system)in order to make it suitable with Iraqi government Corporations. the study depend upon main hypothesis which is (the performance level of the strategic perspective of governance system is depending upon work according to the perspective dimensions itself. From the main conclusions:-It is possible to building a strategic perspective
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One of the most significant elements influencing weather, climate, and the environment is vegetation cover. Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-up Index (NDBI) over the years 2019–2022 were estimated based on four Landsat 8 TIRS’s images covering Duhok City. Using the radiative transfer model, the city's land surface temperature (LST) during the next four years was calculated. The aim of this study is to compute the temperature at the land's surface (LST) from the years 2019-2022 and understand the link, between LST, NDVI, and NDBI and the capability for mapping by LANDSAT-8 TIRS's. The findings revealed that the NDBI and the NDVI had the strongest correlation with the
... Show MoreThis research aims to predict the value of the maximum daily loss that the fixed-return securities portfolio may suffer in Qatar National Bank - Syria, and for this purpose data were collected for risk factors that affect the value of the portfolio represented by the time structure of interest rates in the United States of America over the extended period Between 2017 and 2018, in addition to data related to the composition of the bonds portfolio of Qatar National Bank of Syria in 2017, And then employing Monte Carlo simulation models to predict the maximum loss that may be exposed to this portfolio in the future. The results of the Monte Carlo simulation showed the possibility of decreasing the value at risk in the future due to the dec
... Show MoreIn this paper , some of lexical stylistic , syntactical stylistic devices , and one phonetic stylistic device are going to be illustrated in the study of the aphorisms of “life and death” . These stylistic devices are parallelism , hyperbole , alliteration , meiosis , irony , oxymoron , cliché , litotes , metalepsis , and loose sentences. This paper aims at identifying the functions and the frequencies of these devices. These stylistic devices make one speech and writing more interesting and help to get the attention of readers/ listeners
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من الاهمية دراسة التاريخ كونه يمدنا بحلول للمشكلات المعاصرة في ضوء خبرات الماضي، ودراسة سلبيات وايجابيات هذه الحلول، وانطلاقا من مبدأ أن ذوي الإعاقة البصرية طاقة بشرية لابد من استثمارها بما يخدم تقدم وازدهار المجتمع، فمن الأهمية تسليط الضوء على هذه الفئة والإسهام بنقل صورة مشرفة عنها، قد تكون دافعا للآخرين ممن اوقفهم انطفاء شعاع النور والبصيرة عن اكمال حياتهم لشرارة امل تعيد لهم شغفهم في الحياة، وته
... Show MoreStatistics indicate criminal in most countries of the world that the suicide rate continues to increase, as it prevalence manufacturing and complexity of life and the intensification of conflicts and escalating problems of rising suicide rates. And suicide is death intentional, that is, the intentional act that leads to ending the life of the individual and self-on purpose. The current research aims to identify the suicide in terms of its causes and its factors and come up with recommendations for the prevention of suicide. Because suicide is a life-threatening problem has tried several theories of interpretation and stand on its grounds. Considering the theories of psychoanalysis (Freud) that suicide is the result of the individ
... Show MoreOral squamous cell carcinoma (OSCC) is the most common malignant neoplasm of the oral mucosa. Human papillomavirus (HPV) virus cause a broad scope of diseases from benign to invasive tumors, types 16 and 18 classified as carcinogenic to humans. This study aimed to provide the first molecular characterization of HPV types in Iraq. Thirty-five unstimulated whole saliva samples were collected from histopathologically confirmed patients with oral cancer were enrolled in this study. Genomic DNA was extracted from exfoliating cells to amplify HPV-DNA using HPV-L1 gene sequence primers by polymerase chain reaction method (PCR), the viral genotyping was performed using direct sequencing method. HPV genotypes identified were deposited in Gen
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