VLSI implementation of heart sounds maximum entropy spectral estimation

Thesis (M.E.Sc.) -- University of Adelaide, Dept. of Electrical Engineering, 199

Galvanic Corrosion of Orthodontic Brackets and Wires in Acidic Artificial Saliva: Part II

Objective: Orthodontic wires should have high resistance against corrosion in the oral environment. Since the effect of pH on corrosion has been well recognized, this study sought to assess and compare the electrochemical corrosion of orthodontic brackets and wires of different brands in   acidic artificial saliva.Methods: This in vitro experimental study was conducted on 24 mandibular central incisor brackets of 4 manufacturers namely Dentaurum, American Orthodontics, Shinye and ORJ. The brackets were immersed in acidic artificial saliva along with stainless steel (SS) or NiTi 0.016 round wires for 28 days. All specimens were weighed before and after the experiment by a digital scale. After the experiment, the specimens were evaluated under a light stereomicroscope and specimens with corrosion were further assessed by scanning electron microscope (SEM) and energy-dispersive X- ray spectroscopy (EDX). Two-way ANOVA was used for statistical analysis.Results: The mean corrosion rate (CR) was -1.80, 0.11, 0.05 and -0.93 mpy for Dentaurum, American Orthodontics, Shinye and ORJ brackets, respectively in combination with NiTi wire; these values were 0.46, -0.71, 0.87 and -0.27 mpy, respectively in combination with SS wires; the differences in this regard were not statistically significant (p>0.05). Micrographs showed high corrosion in ORJ brackets followed by Shinye brackets. EDX showed that the combination of ORJ bracket with SS wire had the highest iron (Fe) content and the highest CR.Conclusion: SS brackets manufactured by Shinye and ORJ companies in combination with SS wires showed higher CR in acidic artificial saliva compared to other bracket/wire combinations

Galvanic Corrosion and Ion Release from Different Orthodontic Brackets and Wires in Acidic Artificial Saliva

Objective: Corrosion resistance is among the most important properties of metal alloys used in the oral cavity. Consumption of acidic foods reduces the salivary pH and intensifies the corrosion of brackets and orthodontic wires. This study aimed to compare electro galvanic corrosion of different orthodontic brackets and wires and determine the amount of ions released into acidic artificial saliva. Methods: In this in vitro experimental study, 24 mandibular incisor brackets of 4 different manufacturers (Dentaurum, American Orthodontics, Shinye and ORJ) with stainless steel (SS) or nickel-titanium (Ni-Ti) round wires 0.016 were immersed in acidic artificial saliva for 28 days and their potential difference with the reference electrode was recorded. The amount of released ions was measured in the solution using atomic absorption method. Data were analyzed using two-way ANOVA and repeated measures ANOVA.Results: The mean amount of ions released was not significantly different between groups (p>0.05). The potential difference of Shinye brackets coupled to SS wire was significantly lower than that of other combinations and was negative throughout the study. The potential difference of Dentaurum bracket-NiTi wire, ORJ bracket-NiTi wire, Shinye bracket-SS wire and ORJ bracket-SS wire combinations at the end of experiment was negative as well.Conclusion: The galvanic corrosion of Shinye bracket coupled to SS wire in acidic artificial saliva was greater than that of other bracket-wire combinations. The specimens were not significantly different in terms of the released ions

STRATIGRAPHY OF THE LOWER OLIGOCENE NUMMULITIC LIMESTONES, NORTH OF SONQOR (NW IRAN)

The lower Oligocene hyaline and porcellaneous larger foraminifera of a carbonate platform setting, north of Sonqor, were studied for high-resolution biostratigraphy in the context of European standard zonation (Shallow Benthic Zones). According to the geological map of Kermanshah, these beds were previously ascribed to the Miocene. The identified larger foraminifera include Nummulites fichteli Michelotti, Nummulites vascus Joly & Leymerie, Operculina complanata (Defrance), Asterigerina rotula (Kaufmann), Planorbulina bronnimanni Bignot & Decrouez, Discogypsina discus (Goës), Gypsina mastelensis Bursch, Halkyardia maxima Cimerman, Stomatorbina concentrica (Parker & Jones), Praerhapydionina delicata Henson, Penarchaias glynnjonesi (Henson), Austrotrillina aff. paucialveolata Grimsdale, and Haddonia heissigi Hagn, associated with the coralline alga Subterraniphyllum thomasii Elliott. The foraminiferal association characterises the SBZ 21 Zone (early Rupelian)

Comparison of the value of multidetector-row computed tomography in diagnosis of biliary obstruction reasons with the results obtained from invasive procedures

زمینه و هدف: تصویر برداری تشخیصی نقش اساسی در تشخیص غیر تهاجمی علل انسداد صفراوی و غربالگری بیماران با ریسک بالا را دارا می باشد. این مطالعه با هدف مقایسه ارزش سی تی اسکن مولتی اسلایس در تشخیص علل انسداد صفراوی با یافته های حاصل از روش های تهاجمی انجام شده است. روش بررسی: در این مطالعه توصیفی ـ تحلیلی به روش سرشماری، کلیه بیمارانی که از بهمن ماه 1388 تا خرداد ماه 1390، (50 بیمار)، دارای تشخیص انسداد صفراوی، بر مبنای یافته های کلینیکی و سونوگرافیک بودند، با روش سی تی اسکن مولتی اسلایس (MDCT) بررسی شدند و گزارش رادیولوژی آن ها با یافته های حاصل از سایر روش های تهاجمی شامل تکنیک کلانژیوگرافی معکوس از طریق آندوسکوپ (ERCP)،PTC (Percutaneous transhepatic cholangiography) و یا جراحی مورد مقایسه قرار گرفت. یافته ها: یافته ها نشان داد که حساسیت، ویژگی و دقت سی تی اسکن مولتی اسلایس در تشخیص علل بدخیم انسداد صفراوی به ترتیب 100، 4/88 و 94، در تشخیص علل خوش خیم انسداد صفراوی به ترتیب 75، 100 و 96، در تشخیص سنگ صفراوی به ترتیب 4/94، 100 و 98 بود و رابطه معنی داری بین شدت اتساع مجاری صفراوی و خوش خیم بودن یا بدخیم بودن عامل انسدادی وجود داشت (001/0>P). نتیجه گیری: بر مبنای یافته های این مطالعه، سی تی اسکن مولتی اسلایس روشی سریع ،غیر تهاجمی و با دقت بالا در تشخیص علل انسداد صفراوی و افتراق عوامل انسدادی خوش خیم از عوامل بدخیم بوده و برنامه ریزی قبل از عمل جراحی مفید می باشد

Investigation of the Relationship between Accounting Conservatism and Earnings Management Using Benford's Law in Listed Companies of Tehran Stock Exchange

The present study investigates the relationship between accounting conservatism and earnings management using Benford's Law. In this study, the quantitative index of conservatism (cscore) by Khan & Watts (2009) was considered as the accounting conservatism. Target sample includes 363 listed companies in Tehran Stock Exchange during 1999-2015. Divergence between the actual earning and loss frequencies and Benford' distribution has been taken into account. Chi-square and Z-statistic tests, regards to degrees of conservatism were applied. The results revealed that in companies with low or high levels of conservatism, distribution of earning and lose first to fourth digits follow Benford's law. However the distribution of first and second digits of earning, and first to fourth digits of losses differ from the expected distribution when there is an increase in conservatism. Divergence between the third and fourth digits and expected distribution reduced, when conservatism increases

Comparison of Changes in Mandibular Third Molar Angulation Following First/Second Premolar Extraction versus Non-Extraction Orthodontic Treatments

Objective: Extraction of premolars is believed to affect the eruption of third molars. This comparative study aimed to assess the change in angulation of third molars following first/second premolar extraction versus non-extraction orthodontic treatments.Methods: This historical cohort study was conducted on patients assigned to three treatment groups: extraction of mandibular first premolars (group A), extraction of mandibular second premolars (group B) and non-extraction orthodontic treatment (group C). Each group included 30 third molars. Patients were in the age range of 11-19 years and the third molars were in Nolla’s6-8 stage of tooth development. Pre- and post-treatment panoramic radiographs were analyzed.Results: The angle between the long axis of the mandibular third molar and mandibular plane increased by 7 (2.2°) in group A and 5.2° in group B and the increase in both groups was statistically significant (p<0.05). Angular changes in group C were not statistically significant (p>0.05). The angle between the long axes of mandibular first and third molars decreased by 6.83 (0.3°) in group A. This reduction was statistically significant (p<0.05).Conclusion: In extraction orthodontic treatments (versus non-extraction treatments), mandibular third molars tend to straighten up and become upright so the risk of their impaction may be decreased

The estimation of investment risk in an asset portfolio by using value at risk method (VAR)

This study attempts to use value at risk method (VAR) as risk measurement criterion in formation of household asset portfolio. To do this, the data which are related to the assets price including: bank deposit, bonds, stock, exchange, coin, and housing that are used in time period of 1991 to 2011 and the value at risk of portfolio is calculated in reliability level of 90%, 95%, and 99% and in time periods of one year and 19 years. After calculating returns, return standard deviation, correlation coefficient among assets and VAR of every asset, the optimal mix of assets is extracted by using variance- mean model and Matlab software and assets portfolio risk is calculated by VAR method. The results indicated that there is the most portfolio risk of 55/13% with the probability of 99% for high risk people and the lowest portfolio risk of Zero%, with the probability of 90% for low risk people. In one year period, there is also the most portfolio risk of 17/51% with the probability of 99% for high risk people and the lowest portfolio risk of 88% with the probability of 90% for low risk people

The estimation of investment risk in an asset portfolio by using value at risk method (VAR)

This study attempts to use value at risk method (VAR) as risk measurement criterion in formation of household asset portfolio. To do this, the data which are related to the assets price including: bank deposit, bonds, stock, exchange, coin, and housing that are used in time period of 1991 to 2011 and the value at risk of portfolio is calculated in reliability level of 90%, 95%, and 99% and in time periods of one year and 19 years. After calculating returns, return standard deviation, correlation coefficient among assets and VAR of every asset, the optimal mix of assets is extracted by using variance- mean model and Matlab software and assets portfolio risk is calculated by VAR method. The results indicated that there is the most portfolio risk of 55/13% with the probability of 99% for high risk people and the lowest portfolio risk of Zero%, with the probability of 90% for low risk people. In one year period, there is also the most portfolio risk of 17/51% with the probability of 99% for high risk people and the lowest portfolio risk of 88% with the probability of 90% for low risk people

The estimation of investment risk in an asset portfolio by using value at risk method (VAR)

This study attempts to use value at risk method (VAR) as risk measurement criterion in formation of household asset portfolio. To do this, the data which are related to the assets price including: bank deposit, bonds, stock, exchange, coin, and housing that are used in time period of 1991 to 2011 and the value at risk of portfolio is calculated in reliability level of 90%, 95%, and 99% and in time periods of one year and 19 years. After calculating returns, return standard deviation, correlation coefficient among assets and VAR of every asset, the optimal mix of assets is extracted by using variance- mean model and Matlab software and assets portfolio risk is calculated by VAR method. The results indicated that there is the most portfolio risk of 55/13% with the probability of 99% for high risk people and the lowest portfolio risk of Zero%, with the probability of 90% for low risk people. In one year period, there is also the most portfolio risk of 17/51% with the probability of 99% for high risk people and the lowest portfolio risk of 88% with the probability of 90% for low risk people