25 research outputs found

    Intracanal Retention of Glass Fiber Posts

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    Objective: Fiber-reinforced composite (FRC) posts have recently become more popular for restoring endodontically treated teeth because of providing esthetics, better stress distribution and lower risk  of root fracture. Resistance against tensile forces dislodging the post from the root canal is a prerequisite for these posts. This study aimed to evaluate the tensile retention (strength) of intracanal glass fiber posts produced by three manufacturers.Methods: In this interventional study, the crowns of 30 sound human maxillary central incisors were cut at the cementoenamel junction and the roots were endodontically treated. Post space was prepared to a length of 10mm and the specimens were divided into three groups of 10. HtCo, Anthogyr and Svenskposts were used in groups 1, 2 and 3, respectively. The posts were cemented with Panavia F2 resin cement according to the manufacturer’s instructions. Specimens were then immersed in water at 37°C for 30 days and were then subjected to 7500 thermal cycles between 5- 55°C. Intracanal tensile retention (strength) was measured at a crosshead speed of 0.5 mm/min. Data were analyzed using one-way ANOVA at p<0.05 level of significance.Results: The mean retention was 188.53 (15.43), 183.81 (16.37) and 192.19 (17.50) N in Htco, Anthogyr and Svensk posts, respectively. Statistical analyses showed no significant difference in this regard among groups (p=0.111).Conclusion: Within the limitations of this study, retention of HtCo glass fiber posts in the root  canals was similar to that of two other posts

    The Life and Works of Sadid al-Din Kazeroni: An Iranian Physician and Anatomist

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    Background: One of the great physicians in Iran who had expertise in medicine, surgery, and pharmacy was Sadid al-Din Kazeroni. He was a 14th century physician. No information is available on his birth and death – only “Al-Mughni”, a book, has been left to make him famous in surgical and medical knowledge. Methods: We used desk and historical research methods in this research, with a historical approach. This commonly used research method in human sciences was used to criticize and study the birthplace and works of Sadid al-Din Kazeroni. Results and Conclusion: Sadid al-Din Kazeroni discussed the exact issues in the field of anatomy, surgery, and gynecology. He was fluent in pharmacology. In his pharmacology book, for the first time, he named drugs considered necessary before and after surgery. In this study, we reviewed the biography and introduction of the works and reviewed “Al-Mughni”, a book on breast cancer

    Does Age Affect Outcomes of Percutaneous Nephrolithotomy?

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    Introduction: The present study aimed to assess the efficacy and safety of percutaneous nephrolithotomy (PCNL) in elderly patients. Materials and Methods: We retrospectively reviewed 50 PCNLs performed in the elderly patients (age > 65 years) carried out in our clinic from 2001 through 2007 and compared those with 248 PCNLs performed in younger patients (age < 40 years) during the same period. Results: No significant difference was seen in calculus burden between the two groups. The success rates (stone-free patients and patients with residual calculi < 4 mm) were 85% for the elderly patients and 90% for the younger patients (P = .45). The major composition of calculi was calcium oxalate in 58% and 66.5% of the elderly and younger groups, respectively. No significant complication was observed in the elderly group. Fever without sign and symptoms of bacteremia was seen in 3 patients of each group (8.0% versus 1.2%, P = .004). The operative time was 75.0 ± 6.4 minutes and 76.0 ± 5.1 minutes (P = .25), and the mean hospital stay was 3.7 ± 0.3 days and 3.8 ± 0.9 days (P = .80) in the elderly and younger patients, respectively. Conclusion: We found that PCNL in patients over 65 years was a safe and reliable technique with a stone-free rate of 85% for all types of calculi. Well-controlled comorbidities do not increase the risk of operation. It seems that despite the higher medical risk in the elderly patients, PCNL could be safe and yields a high stone-free rate

    On the volume of fluid simulation details and droplet size distribution insider rotating packed beds

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    In this research, the volume of fluid (VOF) method is used to study the hydrodynamics of rotating packed beds (RPBs). The model is validated, and grid independence analyses are performed for cases with different operating conditions. The droplet size distribution is investigated to characterize the hydrodynamics of RPBs. Droplet size distributions are compared in two-dimensional and three-dimensional simulations, and it is demonstrated that two-dimensional simulations can provide an accurate prediction while significantly reducing the significant computational cost. Radial distributions of droplet diameter in the packing region are studied, and different trends are observed at different rotational speeds (fluctuating at ω = 250 rpm, increasing–constant at ω = 500 rpm, and decreasing at higher rotational speeds). These trends are explained using the breakup and coalescence of droplets during droplet–packing and droplet–droplet collisions. Breakup, coalescence, and deposition regimes of droplets depend on the Weber, Ohnesorge, and impact parameters. We observed that with increasing rotational speed, the average droplet diameter and its standard deviation decreased, while changing the liquid flow rate did not significantly affect the average droplet diameter. It is also observed that there is a critical rotational speed (depending on the bed configuration), beyond which the average droplet size does not decrease with increasing rotational speed

    Integrated Use of n-Alkanes and PAH to Evaluate the Anthropogenic Hydrocarbon Sources and the Toxicity Assessment of Surface Sediments from the Southwestern Coasts of the Caspian Sea

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    Polycyclic aromatic hydrocarbon (PAH) compounds and normal alkanes form a large group of undegradable environmental contaminats. This study aims to determine the sources and distribution of oil pollution (PAH compounds and normal alkanes) in the sediments of the southwestern coastal areas of the Caspian Sea and to compare their levels with the relevant standards. For this purpose, 18 surface sediment samples were collected from depths of 10, 20, and 50 meters along two transects in the vertical direction located in the coastal areas of Sangachin and Hashtpar (Gilan Province). The samples were then examined using mass-spectrometric gas chromatography. The origins of n-alkanes were identified using CPI index (0.76-0.95), U/R (3.30‒6.57), and Pristane/Phytane (0.21‒0.42). The sources of PAHs were determined using the index ratios of LMW/HMW (1.93‒13.37), Phenanthrene/Anthracene (11.44‒ 16.7), Chrysene/Benzo (a) anthracene (4.69‒10/33), Fluoranthene/Pyrene (0.53‒0.69), and MP/P (0.05‒0.08). Results confirmed the dominant petrogenic source of the hydrocarbons found in the region. The total concentrations of 30 aliphatic hydrocarbons and PAHs in the sediments ranged from 823.8 to 3899.5 µg/g and from 626.95 to 3842.5362 ng/g, respectively. Comparison of the measured PAH concentrations with US sediment quality guidelines revealed that the levels of naphthalene, fluorine, Acenaphthylene, and Acenaphthene exceeded the ERLs at stations with depths of 50m in Sangachin and Hashtpar while comparisons with Canadian standards indicated that they were higher than PELs at all the stations sampled. A major point of great concern is the high concentration of naphthalene as the most toxic PAH compound, which naturally warrants due attention to adopt appropriate management programs

    Introduction of Manuscript: Mokhtasar Andar Elm Teb (Available in the Library of Leiden, The Netherlands)

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    This article is a brief history and the manuscript of the book “Mokhtasar Andar Elm Teb” by Zrdglym. This manuscript is now, with No. 604 in Leiden library. In this version, the text states the manuscripts of three books respectively entitled “Andar Elm Teb”, ”Bahnameh” and the third book did not mention. This version is about 167 pages in which 70 pages are about “Andar Elm Teb”. In this article, Zardglym biography is made, then the authenticity of this work is investigated and analyzed. Finally, a list of the contents of the book in details is scrutinized. A survey was conducted and found that the author of the second book attributed to Zardglym. Although the third book is attributed to Zardglym, comparing to its introduction and its texts, it is the manuscript of Seyed Esmail Gorgani

    Does fasting in Ramadan ameliorate Lipid profile? A prospective observational study

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    Background and Objectives: There are conflicting data on the effects of fasting in Ramadan in Muslim countries on Lipid profile. We aimed to evaluate the effect of fasting on lipid profiles and some ratios which are strong for predicting cardiovascular disease. Methods: This prospective observational study was done in Iran in 2012. Forty three persons were enrolled into the study. Their anthropometric measurement was done. Fasting plasma high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), total cholesterol (TC), and triglyceride (TG) were measured at baseline and after one month fasting during Ramadan by standard methods. Paired t test were used to compare lipid profiles before and after the intervention. Results : High density lipoprotein cholesterol was 33.10±6.53 mg/dL at baseline and increased to 42.49±8.44mg/dL (P <0.001). Fasting in Ramadan decreased serum LDL/HDL and TG/HDL ratios significantly (P <0.001). Triglyceride levels were unaffected. Low density lipoprotein and total cholesterol levels increased (P=0.008). Changes did not differ significantly between men and women. Conclusion: Fasting in Ramadan is effective to ameliorate High density lipoprotein, and LDL/HDL and TG/HDL ratios. Omitting one meal may be considered to control High density lipoprotein level

    Effects of Biebersteinia multifida hydro-ethanol extract on proliferation and apoptosis of human prostate cancer and human embryonic kidney cells

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    Objective: Biebersteinia (Geraniaceae) has a history of use in traditional medicine in some countries including Iran. In the present study, cytotoxic and apoptogenic properties of hydro-ethanol extract of B. multifidi was investigated on human prostate cancer cell lines (PC3 and DU 145) and human embryonic kidney 293 (HEK293) cells. Materials and Methods: Cells were cultured in RPMI-1640 medium supplemented with 10% FBS at 37ºC in a humidified atmosphere of 95% air and 5% CO2. The root of the plant was macerated with EtOH 70%. Cytotoxic activity of ethanol extract of B. multifida was assessed using alamarBlue® assay after 48 hr of treatment. Apoptotic cells were stained with propidium iodide (PI) and detected by flow cytometry (sub-G1 peak). Results: B. multifidi had cytotoxic effect on malignant cells and normal HEK293 cells in a dose-dependent manner and significantly decreased the cell viability (IC50 values were between 199.2 and 302.9 µg/ml). B. multifida increased the sub-G1 peak in flow cytometry histogram of treated PC3 cells compared to control showing the induction of apoptosis and DNA fragmentation. Conclusion: Due to cytotoxic and apoptotic activity of B. multifida, the plant is suggested for further phytochemical analysis and mechanistic evaluation

    Efficient dispersion of magnetite nanoparticles in polyurethane matrix through solution mixing and investigation of the nanocomposite properties

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    Recent studies on inorganic/polymer nanocomposites have shown enhancements in thermal, mechanical, and chemical properties over the neat polymer without compromising density, toughness, and processibility. When nanoparticles are incorporated into the polymer matrix, significant enhancements in thermal and mechanical properties of the nanocomposite are observed. The present study is focused on the preparation and characterization of nanosize magnetite-reinforced PU composites, which induces magnetic properties to a specific thermoplastic polyurethane elastomer. The nanocomposites are prepared and the effects of magnetite content on thermal, mechanical, and magnetic properties of the nanocomposites are evaluated. Ultrasonication was used to disperse the nanoparticles and break up any large clumps and aggregates and followed by mechanical mixing. The magnetic nanocomposites were characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). Characterization of the magnetic nanocomposite by FT-IR showed a successful incorporation of magnetite nanoparticles into the polymeric matrix. TGA and magnetometry of the magnetic nanocomposites revealed the amount of magnetite that was incorporated into the polymeric phase. Finally, the corresponding magnetization behavior of the nanocomposites was studied.status: publishe
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