788 research outputs found
Study of mycoflora in cultured Indian white shrimp (Penaeus indicus) in Abadan, Iran
The development of the commercial culture of penaeid shrimps has been accompanied by the occurrence of infectious and noninfectious diseases. The most important penaeid diseases are caused by organisms that are part of the normal microflora of penaeids. In 1998, the samples were collected from five farms in Ghofase area (Ahadan) 2-5 ponds in each farm. The shrimps of these ponds were preserved in full hygienic conditions, from each pond, at least 5 samples were collected and then transferred to the Aquatic Diseases Laboratory of Khouzestan Fisheries Research Center. The main tissues of Gill, Hemolymph, Hepatopancreas and cuticle of live-shrimps were studied in the laboratory. In this research, a total of 40 fungal species were isolated from different tissues with high abundance in Hepatopancrease (19 species) and Hemolymph (12 species). Aspergillus niger was identified as the most abundant species
Optimizing an Adaptive Neuro-Fuzzy Inference System for Spatial Prediction of Landslide Susceptibility Using Four State-of-the-art Metaheuristic Techniques.
Four state-of-the-art metaheuristic algorithms including the genetic algorithm (GA), particle swarm optimization (PSO), differential evolutionary (DE), and ant colony optimization (ACO) are applied to an adaptive neuro-fuzzy inference system (ANFIS) for spatial prediction of landslide susceptibility in Qazvin Province (Iran). To this end, the landslide inventory map, composed of 199 identified landslides, is divided into training and testing landslides with a 70:30 ratio. To create the spatial database, thirteen landslide conditioning factors are considered within the geographic information system (GIS). Notably, the spatial interaction between the landslides and mentioned conditioning factors is analyzed by means of frequency ratio (FR) theory. After the optimization process, it was shown that the DE-based model reaches the best response more quickly than other ensembles. The landslide susceptibility maps were developed, and the accuracy of the models was evaluated by a ranking system, based on the calculated area under the receiving operating characteristic curve (AUROC), mean absolute error, and mean square error (MSE) accuracy indices. According to the results, the GA-ANFIS with a total ranking score (TRS) = 24 presented the most accurate prediction, followed by PSO-ANFIS (TRS = 17), DE-ANFIS (TRS = 13), and ACO-ANFIS (TRS = 6). Due to the excellent results of this research, the developed landslide susceptibility maps can be applied for future planning and decision making of the related area
Appraisal of intra-reservoir barriers in the Permo-Triassic successions of the Central Persian Gulf, Offshore Iran
Owing to their tightness, intra reservoir barriers have the potential to prevent homogenization of reservoir fluids and so cause compartmentalization. Identification of these barriers is an important step during reservoir evaluation. In order to achieve this, three main approaches: i) detailed petrographic and core analysis, ii) petrophysical studies (flow unit concept) and iii) geochemical analysis (strontium residual salt analysis) were applied systematically in the Permo-Triassic carbonate reservoirs (Dalan and Kangan formations) of a supergiant gas reservoir located in the Central Persian Gulf. Integration of these approaches has led to a fullclarification of the intra reservoir barriers. Petrographic examinations revealed the potential stratigraphic barriers to fluids flow created by various depositional/ diagenetic characteristics. Petrophysical data such as poroperm values, pore throat size distribution and scanning electron microscopy (SEM) analysis were used to differentiate the reservoir flow units from non-reservoir rock. According to different trends in 87Sr/86Sr ratios of residual salts, the existence of flow barriers was evaluated and proved. Finally, by integrating these approaches, three intra reservoir barriers were introduced in the studied reservoir interval. These intra reservoir barriers are depositional and diagenetic in nature and are located in stratal positions with sequence stratigraphic significance. The possibility of reservoir compartmentalization was evaluated in the studied wells, and then their existence was predicted at the adjacent fields. As shown in this study, integration of petrographic examinations with flow unit determination in a sequence stratigraphic framework has the potential for recognizing intra reservoir barriers and predicting compartmentalization of the studied Permo-Triassic reservoirs
Effects of mineral trioxide aggregate on the osteogenesis of normal human osteoblasts
Thesis (M.S.D.)--Boston University, Henry M. Goldman School Dental Medicine, 2003 (Endodontics).Includes bibliography (leaves 88-100).A novel material, Mineral trioxide aggregate (MTA) has been used in endodontics for sealing the roots of teeth and has been reported to produce biological response. Many studies have been done on biocompatibility and cytotoxicity of this material. However, there are many unidentified factors in the response of various cells, such as osteoblasts to MTA.
In this in vitro study, effects of MTA on cell attachment efficiency, cell proliferation, osteocalcin expression and alkaline phosphatase (ALP) activity of human osteoblasts were tested. Human osteoblast-like cells, derived from healthy alveolar bone were used for all of the experiments in this study. All of the experiments were performed using cells from second passage.
Cells in the experimental, MTA group and controls were cultured in Dulbecco’s Modified Eagle Medium (DMEM) supplemented with F-12 nutrient mixture, fetal bovine serum (FBS), penicillin G (5000 U/ml)/streptomycin sulfate (5000 [mu]g/ml), and 250 [mu]g/ml Amphotericin B. Cells were cultured for periods of 12 and 20 days. MTA was mixed according to manufacturer’s instructions, and made into discs of ~0.5 mm thickness in a cuIture hood, and maintained in 37[degrees]C, 5% Co2 and 1OO% humidity and allowed to set for 24 hours. Differentiation medium, culture medium supplemented with Vit. D3, was used for all culture for 48 hours. Cells were screened for osteoblast phenotype prior to all experiments. The pH changes in the culture medium was observed and recorded. Cell attachment efficiency and proliferation were determined by measuring the optical density of crystal violet dye in fixed culture cells. ALP activity was determined by measuring optical density of released p-Nitrophenol in extracted culture media.
Osteocalcin expression was determined by measuring [125]l-labeled antibody in extracted culture media. All data were normalized on per 10[5] ceils basis and a two sample t-test assuming equal variances was used for statistical analysis. Mean pH value of culture medium increased during culture period, cell attachment efficiency was significantly higher in cells cultured in presence of MTA (p[less than]0.0001). Cell proliferation rate was significantly higher in MTA group (p[less than]0.0001) after 12 day of culture. There were significantly higher number of cells in presence of MTA both at 12 and 20 days (p[less than]0.001), ALP activity of cells in presence of MTA was significantly higher than control at 12 days (p[less than]0.05).
However, cells in the control exhibited significantly higher osteocalcin expression at 12 days (p[less than]0.01). Based on the results of this in vitro study, MTA is capable of stimulating some osteogenic effects in normal osteoblast-like cultures. Further studies needed to evaluate exact mechanism of action of this material on osteoblasts
Evaluating urban housing development patterns in developing countries: Case study of Worn-out Urban Fabrics in Iran
The restoration of Worn-out Urban Fabrics (WoUFs), i.e., the disfiguration of fabric components of the city from their main shape, and the implementation of the urban housing development plan have always been pivotal activities for designing livable cities – especially in developing countries. Prior research, however, did not identify an appropriate model of sustainable housing development for the recovery of WoUFs. To fill this gap, housing development patterns – i.e., supportive housing, Mehr housing, rental, and social housing – aimed at restoring the WoUF of the Hemmatabad district in Isfahan city (Iran) were studied. Expert opinions, on the criteria affecting the selection of housing development patterns, from 40 professionals in urban management and urban development models were collected and then analyzed by the Analytic Hierarchical Process and VIKOR method. It resulted that, in order to revive the WoUF of Hemmatabad, social housing is the more desirable pattern of housing development (Qi = 1) compared to supportive housing (Qi = 0.911), Mehr housing (Qi = 0.117) and rental housing (Qi = 0.004). Results help governments of developing countries in directing their effort in the decision of which housing development pattern for WoUFs to implement
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Influence of tempering and normalising on the structure and properties of low alloy and plain carbon-manganese steels
The influence of tempering on the impact and tensile properties of various types of microstructures has been examined. The following heat treatments were investigated during the course of this project.
• The structure property relationships for two quenched and tempered C- Mn-Al steel flanges made to ASTM A350 LF2 specification have been determined. Samples heated to temperatures in the range 900 - 1250°C to produce a wide range in 7 grain size and quenched in oil or iced water followed by tempering at 300, 600, 650 and 700°C to produce a variety of commercially obtainable micro-structures. Impact transition curves as well as the tensile strength and the Vickers hardness values were obtained. Increasing the cooling rate and quenching temperature increased the hardness and strength.
The microstructural parameters have been determined and related to the Vickers hardness, the yield stress, and impact behaviour. The re-sults obtained have been analysed and it has been found that 7 grain size is the major structural parameter controlling the mechanical prop-erties of these quenched and tempered flanges.
Tempering improved the impact behaviour of quenched steels while the strength and hardness fell. The fall in strength and hardness was found in part to be related to a reduction in dislocation density. How-ever spheroidization of carbides and a reduction in the ky value after tempering are also possible reasons for the further fall in strength. The improvement in impact behaviour, however, is associated with the fall in strength and coarsening of the grain boundary carbides.
• A V free and a V containing steel flange have been examined and the impact and tensile behaviour determined after normalising at 900° C and austenitising at 1050°C . After normalising, both steels had fine grain sizes and passed the ASTM A350 LF2 specification. Austenitising at 1050°C coarsened the grain size and produced a large amount of precipitation hardening in the V steel. However, because of its low S level and higher shelf energy the V steel met the impact requirement, while the V free steel in which there was no precipitation hardening failed the specification
A green vehicle routing problem with customer satisfaction criteria
This paper develops an MILP model, named Satisfactory-Green Vehicle Routing Problem. It consists of routing a heterogeneous fleet of vehicles in order to serve a set of customers within predefined time windows. In this model in addition to the traditional objective of the VRP, both the pollution and customers' satisfaction have been taken into account. Meanwhile, the introduced model prepares an effective dashboard for decision-makers that determines appropriate routes, the best mixed fleet, speed and idle time of vehicles. Additionally, some new factors evaluate the greening of each decision based on three criteria. This model applies piecewise linear functions (PLFs) to linearize a nonlinear fuzzy interval for incorporating customers' satisfaction into other linear objectives. We have presented a mixed integer linear programming formulation for the S-GVRP. This model enriches managerial insights by providing trade-offs between customers' satisfaction, total costs and emission levels. Finally, we have provided a numerical study for showing the applicability of the model
The Role of Proper Use Factor Model for the Prediction of Available Forage in Rangeland in the South of Iran
In Iran, 80 to 90% of the livestock production is associated with rangeland but 48% of the rangeland has been classified as in poor condition (Farahpour, 2002). Available Forage (AF) is that portion of the forage production accessible for use by a specified kind or class of grazing animal. Estimates of AF by plant species, consumption by the animal, and the contribution of the forage to the animal\u27s diet must be synchronised with each other in the same time frame (Valentine, 2001). The Proper Use Factor (PUF) is the degree of utilisation of current year\u27s growth of the vegetation that, if continued, will achieve management objectives and maintain or improve the long-term productivity of the site. The objective of this study was to identify and determine the PUF of forage that cause effect the qualitative and quantitative aspects of AF in rangeland of Bakkan, south Iran
Effects of temperature on hematological and histopathological changes and survival rate of juvenile Fenneropenaeus vannamei experimentally challenged to White Spot Virus
Many shrimp farmers were suffering from White Spot Disease (WSD) onset in last decades. Oscillation of environmental factors could lead mortality in susceptible hosts. Our study was aimed to investigate the effect of different temperatures on juvenile Fenneropenaeus vannamei experimentally exposed to White Spot Virus (WSV). Five hundred and forty juveniles were distributed among 3 treatments in triplicates, 22, 25 and 30°C and experimentally WSV were injected in the shrimps. Our results showed mortality started at 36 h post inoculation (hpi) in the treatment at 25°C (T25), meanwhile the mean value of mortality percent at 54 hpi in T25 (71.10±17.35) showed the significant difference (p=.045) with T22 (3.33±3.33) and T30 (Not Observed, NO.). Our results suggest that in site selection, in primary stage of farm designing, water temperature at more than 29°C, should be considered as key environmental factor. This finding can lead us that why the White Spot Disease occurred with high mortality in some area when the days of shrimp culture were prolonged until mid autumn
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