380 research outputs found

    MARKOV CHAIN MODEL FOR PROBABILITY OF DRY, WET DAYS AND STATISTICAL ANALISIS OF DAILY RAINFALL IN SOME CLIMATIC ZONE OF IRAN

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    Water scarcity is a major problem in arid and semi-arid areas. The scarcity of water is further stressed by the growing demand due to increase in population growth in developing countries. Climate change and its outcomes on precipitation and water resources is the other problem in these areas. Several models are widely used for modeling daily precipitation occurrence. In this study, Markov Chain Model has been extensively used to study spell distribution. For this purpose, a day period was considered as the optimum length of time. Given the assumption that the Markov chain model is the right model for daily precipitation occurrence, the choice of Markov model order was examined on a daily basis for 4 synoptic weather stations with different climates in Iran (Gorgan, Khorram Abad, Zahedan, Tabriz)during 1978-2009. Based on probability rules, events possibility of sequential dry and wet days, these data were analyzed by stochastic process and Markov Chain method. Then probability matrix was calculated by maximum likelihood method. The possibility continuing2-5days of dry and wet days were calculated. The results showed that the probability maximum of consecutive dry period and climatic probability of dry days has occurred in Zahedan. The probability of consecutive dry period has fluctuated from 73.3 to 100 percent. Climatic probability of occurrence of dry days would change in the range of 70.96 to 100 percent with the average probability of about 90.45 percent

    Microscopic Enteritis; Clinical Features and Correlations with Symptoms

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    Aim: To assess the clinical characteristic of CD as well as correlation of symptoms and the degrees of intestinal mucosal lesions in Iranian children. Background: Microscopic Enteritis (Marsh 0-II) is associated with malabsorption. Patients and methods: From August 2005 to September 2009, 111 cases with malabsorption and classical gastrointestinal symptoms were evaluated. Results: The mean (±SD) age of children with CD was 4.9±3.5 years (range, 6 month - 16 years) and the mean duration of symptoms was 8 ± 20.5 months. 50 cases (45%) were female and 61 cases (55%) were male. The most common clinical presentation was failure to thrive in 72%, chronic diarrhea in 65.8% and Iron deficiency anemia in 59.5%. Sensitivity of EMA was 100% in patients with Marsh IIIb and Marsh IIIc. EMA was also positive in 77% of cases with Marsh 0, 18% in Marsh I, 44% in Marsh II and 81.8% in patients with Marsh IIIa. Conclusion: Histopathology did not reflect the severity of gluten sensitivity. This would suggest that the degree of intestinal mucosal damage might not be a reliable prognostic factor. Significant symptoms can be present with minor histological change on biopsy

    Molecular Dynamic Simulation Model for the Growth of Thin Films in The Structure Zone Model

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    A two dimensional molecular dynamic (atomistic) simulation model was used to investigate the relationship between the nano-structure and the deposition parameters; namely, substrate temperature, deposition rate, angle of incidence, surface roughness. Qualitative agreements with the predictions of the structure zone model (SZM) and the theoretical results of Srolovitze and coworkers (1988), as well as expectations through changes in the activated processes during film growth due to changes in deposition parameters (Grovenor and coworkers (1984)) are obtained. It is shown that by enhancing the atomic mobility (i.e., increasing the substrate temperature or/and lowering the deposition rate) films of higher density with fewer voids are produced. By increasing the deposition angle, the nano-structure of the film changes from a dense film with few voids, to a nano-structure with columns/boundless inclined with the same angle ( β ) towards the incidence atoms with elongated voids. The angle β increases with increasing the deposition angle (α ), and in agreement with the tangent rule (Dirks and Leamy (1977)). The angle of bundles (or the angle of the formation of the voids between atomic bundles), and columnar structure are caused by shadowing effects. Results showed that β decreases slowly with increasing surface mobility (i.e., increasing the substrate temperature or/and reducing the deposition rate). In general, the model provides almost all predicted results and agrees well with observation

    Novel 5-oxo-hexahydroquinoline derivatives: design, synthesis, in vitro P-glycoprotein-mediated multidrug resistance reversal profile and molecular dynamics simulation study

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    Overexpression of the efflux pump P-glycoprotein (P-gp) is one of the important mechanisms of multidrug resistance (MDR) in many tumor cells. In this study, 26 novel 5-oxo-hexahydroquinoline derivatives containing different nitrophenyl moieties at C-4 and various carboxamide substituents at C-3 were designed, synthesized and evaluated for their ability to inhibit P-gp by measuring the amount of rhodamine 123 (Rh123) accumulation in uterine sarcoma cells that overexpress P-gp (MES-SA/Dx5) using flow cytometry. The effect of compounds with highest MDR reversal activities was further evaluated by measuring the alterations of MES-SA/Dx5 cells' sensitivity to doxorubicin (DXR) using MTT assay. The results of both biological assays indicated that compounds bearing 2-nitrophenyl at C-4 position and compounds with 4-chlorophenyl carboxamide at C-3 demonstrated the highest activities in resistant cells, while they were devoid of any effect in parental nonresistant MES-SA cells. One of the active derivatives, 5c, significantly increased intracellular Rh123 at 100 mu M, and it also significantly reduced the IC50 of DXR by 70.1% and 88.7% at 10 and 25 mu M, respectively, in MES-SA/Dx5 cells. The toxicity of synthesized compounds against HEK293 as a noncancer cell line was also investigated. All tested derivatives except for 2c compound showed no cytotoxicity. A molecular dynamics simulation study was also performed to investigate the possible binding site of 5c in complex with human P-gp, which showed that this compound formed 11 average H-bonds with Ser909, Thr911, Arg547, Arg543 and Ser474 residues of P-gp. A good agreement was found between the results of the computational and experimental studies. The findings of this study show that some 5-oxo-hexahydroquinoline derivatives could serve as promising candidates for the discovery of new agents for P-gp-mediated MDR reversal

    Seroepidemiology of rubella, measles, HBV, HCV and B19 virus within women in child bearing ages (Saravan City of Sistan and Bloochastan Province)

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    Present survey basically focused on women between 15-45 years of age resident in a town of Sistan and Baluchistan province named as Saravan city located in border of Pakistan-Iran in order to find out the seropositivity against the viruses in child bearing ages in the above stated under study community. This descriptive cross-sectional study was carried-out from 2001 up to 2002. Saravan town was divided into 4 geographical areas and each area was further sub-divided into 10 blocks and in each block 10 families were chosen randomly. In the next step by referring to each family from the chosen married women with specified age i.e., 15-45 years, 5 mL blood was collected. Serum was then separated and stored at -20°C before the assay. ELISA kit was employed to detect anti B19, anti rubella, anti measles, anti HBV and anti HCV antibody. Furthermore during samples collection a questionnaire filled for each woman under study. This study showed that 89.6% of women understudy were seropositive against measles, rubella (96.2%), B19 (59.2%), HCV (0.8%) and HBV (19.8%), respectively. According to the results of no serious problem with rubella in this area; But, about measles, the present immunity against measles in this area is insufficient. It seems that incidence of B19 infection in this region is same as other places in Iran. The rate of seropositivity against HBV and HCV indicated of these viruses circulating in the population in this area. © 2007 Academic Journals

    The Effects of Functional Therapy on Motor Development in Children with Cerebral Palsy

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    ObjectivesThe cause of rheumatoid arthritis (RA) as a chronic inflammatory autoimmune disease is still unknown. It appears that both genetic and environmental factors play a role in its pathogenesis. Recent studies reveal that in addition to the CNS, immune cells synthesis neurotransmitters so that these catecholamines can regulate immune functions. The aim of this study is to evaluate the dopamine receptor gene expression profiles on peripheral blood mononuclear cells of rheumatoid arthritis patients in comparison with normal individuals.Material & MethodsIn the present study, we investigated dopamine receptor gene expression in PBMCs of 40 RA patients and 40 healthy individuals using Real Time-PCR.The specificities of the obtained Real time PCR products for the respective dopamine receptors fragments were confirmed by sequenced analysis capillary systemResultsWe found that DRD1-DRD5 types of dopamine receptors genes expression profiles of rheumatoid arthritis patients differ compared to healthy individuals. Moreover, a significant difference of DR2 and DR4 gene expression was seen in rheumatoid arthritis patients.ConclusionThis study showed that some types of dopamine receptors genes expression profiles alter in rheumatoid arthritis patients with comparison to healthy individuals Moreover, this alteration possibly could result in dysfunction of dopaminergic system in immune cells and finally lead to rheumatoid arthritis

    Antimicrobial resistance of Shigella spp. isolated from diarrheal patients in Zahedan

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    One of the great challenges in the treatment of infectious diseases is the resistance of pathogenic bacteria against antibiotics, and antibiotic resistance to Shigella is broadly observed in different parts of the world. The object of this study was to determine Shigella antibiotic resistance pattern against the antibiotics such as ampicillin, amoxicillin, trimethoprim-sulfamethoxazole, chloramphenicol, nalidixic acid, ciprofloxacin and ceftriaxone. In this cross-sectional study, a total of 147 Shigella strains were collected from the diarrheic patients referring to different medical centers of Zahedan. Specific antisera were used for serotyping of isolated Shigella and their antibiotic resistance patterns were determined by standard Kirby-Bauer method. Of the 147 studied Shigella strains, 102 (69.3) belonged to S. flexneri, 32 (21.7) to S. dysenteriae, 11 (7.4) to S. boydii, and 2 (1.36) to S. sonnei species. The isolated strains showed resistance to ampicillin (99.3), trimethoprimsulfamethoxazole (52) and nalidixic acid (1.3), but there was no resistance against ciprofloxacin and ceftriaxone. According to the findings, it is suggested that antibiotics should not be used without laboratory testing (antibiogram). © 2008 Tehran University of Medical Sciences

    Factors underlying life quality in urban contexts: Evidence from an industrial city (arak, iran)

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    Cities play a vital role in local development providing a high education level, specialized jobs and advanced services. When assessing living conditions and wellbeing in cities, economic indicators alone are generally unable to evaluate the inherent complexity of the 'quality of life' issue in urban environments. With rapid urbanization, shortage of infrastructures and services emerged in metropolitan regions of developing countries, leading to disadvantaged settlements, urban poverty, lower citizens' satisfaction, and an overall decline in life quality. Based on these premises, the present study illustrates a subjective investigation of life quality in an emerging economy such as Iran, focusing on Arak, the fourth largest industrial pole of the country. Based on a literature review on quality of life in industrial cities of emerging economies, subjective indicators of citizens' satisfaction on living quality in Arak were identified and quantified using empirical results from a field survey. Results of our study show that the overall satisfaction for living quality in Arak is rather low, reaching the lowest rank in the issues of environmental sanitation and public transportation. Lack of investments in urban infrastructure justifies the low citizens' perception of life quality in Arak city. The paper concludes outlining the urgent need of homogeneous and comparable macro-and micro-data on multiple aspects of quality of life at both city-level and metropolitan-level in emerging economies

    One-dimensional Modelling and Optimisation of an Industrial Steam Methane Reformer

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    Steam methane reforming is one of the most promising processes to convert natural gas into valuable products such as hydrogen. In this study, a one-dimensional model was used to model and optimise an industrial steam methane reformer, using mass and thermal balances coupled with pressure drop in the reformer tube. The proposed model was validated by the experimental data. Furthermore, the effects of flowrate and temperature of the feed, tube wall temperature, and tube dimension on the reformer performance were studied. Finally, a multiobjective optimisation was done for methane slip minimisation and hydrogen production maximisation using genetic algorithm. The results illustrated the optimum feed flowrate of 2761.9 kmol h–1 (minimum 32 mol.% produced hydrogen and maximum 0.15 mol.% unreacted methane). This is one of the few studies on investigation of steam methane reformer using a simple and effective model, and genetic algorithm. This work is licensed under a Creative Commons Attribution 4.0 International License

    Unraveling urban form and collision risk: The spatial distribution of traffic accidents in Zanjan, Iran

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    Official statistics demonstrate the role of traffic accidents in the increasing number of fa-talities, especially in emerging countries. In recent decades, the rate of deaths and injuries caused by traffic accidents in Iran, a rapidly growing economy in the Middle East, has risen significantly with respect to that of neighboring countries. The present study illustrates an exploratory spatial analysis’ framework aimed at identifying and ranking hazardous locations for traffic accidents in Zanjan, one of the most populous and dense cities in Iran. This framework quantifies the spatiotem-poral association among collisions, by comparing the results of different approaches (including Kernel Density Estimation (KDE), Natural Breaks Classification (NBC), and Knox test). Based on descriptive statistics, five distance classes (2–26, 27–57, 58–105, 106–192, and 193–364 meters) were tested when predicting location of the nearest collision within the same temporal unit. The empirical results of our work demonstrate that the largest roads and intersections in Zanjan had a significantly higher frequency of traffic accidents than the other locations. A comparative analysis of distance bandwidths indicates that the first (2–26 m) class concentrated the most intense level of spatiotem-poral association among traffic accidents. Prevention (or reduction) of traffic accidents may benefit from automatic identification and classification of the most risky locations in urban areas. Thanks to the larger availability of open-access datasets reporting the location and characteristics of car accidents in both advanced countries and emerging economies, our study demonstrates the potential of an integrated analysis of the level of spatiotemporal association in traffic collisions over metropolitan regions
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