More than 90% of Malaysian roads are constructed using asphaltic concrete. However, previous investigations of asphaltic concrete have mainly concentrated on the macroscopic properties of the composite materials based on the assumption that the mixtures are homogeneous and isotropic. This paper applies a digital image processing technique to compare the orientations of coarse Aggregate particles in asphaltic concrete compacted using Marshall, Servopac and Presbox compactors. Aggregate orientation was measured in terms of a vector magnitude and the average major axis angle.  The average major axis angle of all compactors are less than 45o indicating that Aggregate orientation in all of the prepared specimens have the preferential orientation along the horizontal plane. The vector magnitude results of the Presbox compacted sample is the least, indicating the presence of the most randomly oriented Aggregate. However, the Servopac specimens have more randomly oriented Aggregate compared to Marshall specimens. An ANOVA analysis for vector magnitude indicates that only compaction method, not Geometrically Cubical Shaped (GCS) proportion, has a significant impact on Aggregate orientation randomness.

The noticeable brittleness of lightweight Aggregate concrete limits its vast application. Using steel fibers will improve the disadvantage contrived in this type of concrete. Steel fiber increases the ductility and prevention of brittle failure of the concrete. In this paper, the influence of steel fiber on the ability of lightweight concrete to absorb energy during the response in compression has been investigated. For this purpose, steel fiber ratios of 0, 0.5, 1 and 1.5 percent by the volume of the sample were used. The sample with 0.0 percent steel fiber ratio was used as a reference to be compared with other samples. Two types of steel fibers, including hooked-end and crimped, were used. All of the fine and coarse Aggregates were lightweight. The results show that there is no noticeable improvement in the pre-peak energy absorption by adding steel fiber to the composite. The increase of steel fiber ratio changes the shape of the descending branch of the stress-strain curve in compression and increases the compressive toughness of lightweight Aggregate concrete. Furthermore, based on the experimental data, the relationship between compressive strength and steel fiber volume fraction was derived.

Particle size distribution (PSD) and Aggregate stability are two physical properties are important for soil conservation. This study investigates the effect of using different organic matters on the PSD in the wet and dry conditions. The experiment was conducted in randomized complete design with two plant residue treatments namely (straw stubble and pistachio residue) and three moisture levels namely 0, 1 and 5% water by weight in three replications. In addition, soil PSD was measured in two manners, dry (DPSD) and wet (WPSD). The results showed that the above treatments had different influences on the PSD, depending on the type and amounts of added plant residue and large Aggregates used. For the DPSD, median sizes of Aggregates in control, straw stubble (1%w), pistachio residue (1%w), straw stubble (5%w) and pistachio residue (5%w) were 0.228, 0.250, 0.227, 0.394 and 0.294 mm, respectively. In comparison to the results of DPSD relative to wet most frequent practices shifted from 0.125-0.25 mm particles to smaller than 0.125 mm. This finding indicated that the DPSD and WPSD do not follow the same trend. In addition, study of the WPSD indicated that addition of organic matters, aggregation improved and as a result larger Aggregates were formed. It was also determined that application of different organic residues resulted in different amount of aggregation so that this effect was more pronounced in some sizes of Aggregates.

Background and Aim: Three Dimensional obturation of root canal is one of the main goals of root canal therapy to preserve health or reach the regeneration or healing of periapical tissues. Root end filling materials are used in numerous situations to reach the mentioned goals. One of the common root end- filling materials is mineral trioxide Aggregate (MTA) which the foreign and Iranian ones are different in their prices. The aim of this study was to compare the rat connective tissue reaction to Iranian and foreign MTA.Materials and Methods: This was an animal study in which 40 rats were divided into 5 groups of 8 each. The polyethylene tubes filled with foreign (Pro Root MTA) and Iranian (Root MTA) white MTA and were implanted in subcutaneous connective tissue. Similarly, the empty tubes were inserted in subcutaneous connective tissue as control group. The samples were examined histologically after 7, 14, 30, 60 and 90 days and were scored as followings: 0, was characterized to samples without inflammatory cells; without inflammatory reaction 1, for samples with less than 25 inflammatory cells; mild inflammatory reaction. 2, for samples with 25 to 125 inflammatory cells; moderate inflammatory reaction and 3, for ones with more than 125 inflammatory cells; severe inflammatory reaction. The data were analyzed using Kruskal-Wallis test and p<0.05 was considered as the level of significance.Results: In general, inflammatory reactions were reduced in all groups. Experimental groups had moderate to severe inflammation in the 7th day which had significant difference with the control group having mild to moderate inflammation (p=0.04). There was not any significant differences between experimental and control group in 14th, 30th, 60th and 90th days (p>0.05).Conclusion: Based on the findings of this investigation, inflammatory subcutaneous connective tissue reaction to Iranian (Root MTA) and foreign (Pro Root MTA) MTA was the same.

Background and Objectives: One of the common matrials as a root-end filling is Mineral trioxide Aggregate that has different usages in Endodontics. The purpose of this study was to compare the microleakage of gray and White MTA as a root.end filling material.Materials and Methods: 50 single-rooted teeth were divided into two experimental groups of 20 teeth each and two positive and negative control groups of 5.After cleaning, shaping, obturation an cutting away of 3 millimeter from the apex, 3 mm deep preparations were made. The root-end preparation of experimental groups were filled with white MTA and gray MTA. In positive and negative control groups no material was placed. Leakage was determined using a dye penetration method. Leakage was observed with a stereomicroscope at 16 magnifications. Accuracy of 0.1 mm was used for measurements. Data was analyzed using the ANOVA test at the 0.05 level of significance. Results: Amount of leakage was zero and 3 mm in negative and positive control groups, respectively .The mean leakage was 0.5 mm in the white MTA and 0.3 mm in the gray MTA. There was not any significant difference between two experimental groups (P=0.14). Conclusion: There was not any difference between apical leakage when we used white and gray MTA as a root-end filling material in this in vitro study.

Background and Aim: In 1993, Mineral Trioxide Aggregates (MTA), a grey-colored material was introduced to dentistry. A similar product in white-color was also produced later. The aim of this study was to review the literature in order to compare the chemical composition of these two different types of MTA.Materials and Methods: Over 600 articles have been published about the properties of MTA, 33 of which were about chemical and 28 were on its physical properties. In addition, about 80 articles have been published on similarities and differences between MTA and Portland Cements (PC). This article reviews the history of MTA’s manufacturing, its introduction to market, its patent, its commercial brands, and its similarities with PC. We also reviewed size of powder particle, setting form, and also hydration reaction of MTA.Results: Mainly consisting of CaO and SiO2, MTAs and PC have similar compositions. MTA also contains Bi2O3 as an opacifier. The main difference in chemical composition of white MTA and PC with grey MTA is that the latter contains less amount of some minor elements specifically FeO. White MTA has finer particles and crystals compared to the grey one. No phosphate does exist in MTA composition, but during the hydration, this material is able to release calcium and hydroxyl ions which, in reaction to exogenous phosphate, results in hydroxyapatite formation.Conclusion: Both MTA and PC are hydrophilic cements. Regarding the biocompatibility of these materials, MTA is considered suitable for clinical applications; while no permission exists for clinical use of PC.

Background and Aim: One of the materials used for repairing root-end fillings is mineral trioxide Aggregate (MTA).MTA has been reported to remain soft when placed in perforations with a high degree of inflammation. The purpose of this study was to evaluate the effect of environmental pH on the setting and micro structure of MTA.Materials and Methods: In this interventional study, tooth-colored MTA (Pro Root, Dentsply, USA) was mixed according to the manufacture's instructions. The mixture was placed into cylindrical polycarbonate tubes. The specimens were randomly divided in to four groups of 9 and were subjected to a pressure of 3.22 MPa~ 6kg applied for 1 minute in a custom-made condenser device. Each of the 9 specimens were then stored at room temperature and saturated humidity in four plastic plates containing buffer solutions of butyric and propyonic acid with a pH of 4.4, 5.4, 6.4 and 7.4, for 4 days. The Vickers hardness test was performed on each specimen. The microstructures of the specimens were analyzed using a scanning electron microscope after sectioning the specimens with a scalpel. Data were subjected to one-way ANOVA.Results: The lowest and highest PH values were 4.4 and 7.4, respectively. A statistically significant difference was observed between all four groups (p<0.05). Unrelated MTA particles scattered in a non uniform matrix were seen in specimens stored in pH 4.4 solutions whereas cases kept in a pH 7.4 environments had distinctive crystalline structures embedded in a more uniform matrix.Conclusion: The results indicate that the acidic pH of inflamed tissues can adversely affect the setting of MTA.

Statement of problem: Perforation is one of the most important problems which may occur during root canal therapy. To repair the perforation and to cut the relation of the root with the tissue of its peripheral environment, materials with adequate sealing ability and suitable price are needed.Purpose: The aim of this study was to survey the micro leakage of the three materials in the restoration of lateral perforations in the roots of the teeth.Materials and method: In this experimental study, 54 intact molar teeth were selected and assigned randomly to three groups. Canals were prepared with step back technique and perforations were made at the apical third of the roots. The cavities were restored with MTA, Root MTA and Portland Cements type 1. The positive control group was subjected to perforation but no perforations were made in the negative control group. The teeth were covered with two layers of nail varnish restoring in 2% fushin solution for 24 hours after incubation. The teeth were sectioned and their leakage was measured by stereomicroscope. The records were analyzed by one- way ANOVA and LSD (Least Square Differences) test.Results: In the positive group dye was completely entered in all perforation areas while no leakage was observed in the negative group. The statistical test showed no significant difference between MTA and Root MTA groups in terms of leakage (p>0.05). But MTA and Root MTA had significant differences with Portland cement (p<0.0001).Conclusion: Considering the results of this study, Root MTA may be considered as a substitute for Pro Root MTA in root canal treatment; however, using Portland type I cement needs more investigations.

To study the sexual fertility and for a dermination of the mating types of the cause of rice bakanae disease and foot rot, samples of infected rice were collected from different regions of Guilan Province in during 2004.One hundred and thirty and three single-spore isolates were obtained from Khazar while nine isolates from local cultivars. Morphological identification was carried out employing the valid morphological identification keys. For fertility test, crosses were carried out among local isolates on Carrot Agar medium, four pairs of which resulted in fertile crosses. Sixty isolates were crossed with six standard isolates representing three mating populations and six mating types (MATA-1, MATA-2, MATC-1, MATC-2, MATD-1 and MATD-2). Of those isolates 23, 17, and 38% belonged to mating populations A, C and D, respectively. Aall, local isolates with fertile crosses were, included in mating population D. Furthermore, the ascosporous isolated from field perithecia, stood in mating population D. For pathogenicity test, 142 isolates were inoculated to Khazar seedlings nine of which showed no disease symptoms. The results of the study revealed that indicated three mating populations, A (F. verticillioides), C (F. fujikuroi), and D (F. proliferatum) are the cause of rice bakanae disease and foot rot in Guilan province, north of Iran Province.