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by
A. Ghasemi |
Total Records (
7 ) for
A. Ghasemi |
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F. Aram
,
G.H. Shahidi Bonjar
,
M.J. Mahdavi
,
S. Mansouri
,
P. Rashid Farrokhi
,
N. Bana Hosein Pour
,
M. Shekari
,
A. Ghasemi
and
S. Aghighi
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Streptomyces sp. are mostly soil-inhabitants and several species are responsible for important diseases in plants, S. scabies causal agent of Common Scab disease of potato and human S. somaliensis causal agent of Mycetoma. Methanolic extracts of leaves of Myrthus communis and seeds of Terminalia chebula, which had documented uses in Iranian herbal-medicine, were tested for anti-Streptomyces activity against S. scabies. For bioassays, concentration of 50 mg mL-1 of methanolic extracts prepared in dimethyl sulfoxide: methanol (v/v, 1/1) and tested in well diffusion method. Inhibitory zones (IZ) in contrast to controls were measured five days after inoculation at 29°C. Both plants showed high biological activity against S. scabies. Future goals include bioassays on human and further plant pathogenic Streptomycetes. |
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M.H. Djavareshkian
,
F. Talati
,
A. Ghasemi
and
S. Sohrabi
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In this research, combustion process in the combustion
chamber of a DI diesel engine is simulated. Afterwards, results obtained
from the multidimensional simulation of the combustion process are used
in analytical solution of the heat conduction in cylinder wall. An eddy
break-up combustion model and a diesel auto-ignition model were implemented
to simulate the ignition and combustion process. All the simulations were
carried out by the use of FIRE CFD tool. Numerical results were validated
via experimental data for OM_355 DI diesel engine for mean cylinder pressure.
The results show that there have been good agreements between experimental
data and the CFD calculations. The research demonstrated that the combination
of multidimensional CFD simulation and analytical methods is useful for
diesel engine wall heat transfer modeling. Effect of cylinder wall material,
insulation material and thickness were studied in order to obtain lower
heat rejection from the combustion chamber. Using cast iron instead of
alluminium for cylinder material, using insulation and increasing the
insulation thickness resulted in lower outer wall temperature and heat
flux. |
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A. Ghasemi
and
M.H. Djavareshkian
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The objective of this study is to simulate combustion process, pollutant formation and flow field in the combustion chamber of a DI diesel engine converted to work as a dual fuel (Diesel/Natural gas) engine. Effect of natural gas equivalence ratio, in constant diesel pilot injection and piston bowl shape, on the combustion process, pollutant formation and flow field are investigated in 5 cases defined. An eddy break-up combustion model and a diesel auto-ignition model were implemented to simulate the ignition and combustion processes. Experiments were performed on OM_355 DI diesel engine to validate the simulations. Results show that there have been good agreements between experiments and the CFD calculations. |
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M.H. Djavareshkian
and
A. Ghasemi
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The objective of this study, is to simulate spray flow with different break-up models and investigate the processes of spray breakup and mixture formation. Effect of these models on the DI diesel engine combustion and performance is also investigated. The 3 Dimensional Naiver-Stokes equation is solved with SIMPLEC algorithm. An eddy break-up combustion model and a diesel auto-ignition model were implemented to simulate the ignition and combustion process in a diesel engine. All the simulations were carried out by the use of FIRE CFD tool. Results were validated via., available experimental data for OM_355 DI diesel engine for mean cylinder pressure. The results show that there have been good agreements between experiments and the CFD calculations. The research demonstrated that practically all the break-up models are capable of simulating the spray processes, as long as model constants are properly chosen and they affect the combustion simulation results. |
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H. Zolgharnein
,
M. Kamyab
,
S. Keyvanshokooh
,
A. Ghasemi
and
S.M.B. Nabavi
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Genetic variation of four populations of Avicennia marina encompassing the Iranian coastal areas of Persian Gulf were studied using five microsatellite loci. The average number of alleles per locus per population ranged from 4 to 4.6, showing no significant difference among the four populations. The observed heterozygosity (Ho), ranging from 0.782 to 0.960 with an average of 0.864, was comparable in the Iranian populations and much higher comparing to the earlier studies on A. marina in the worldwide range. Significant to highly significant deviations from Hardy-Weinberg expectations were observed in 10 out of 20 (five loci H four populations) cases. Most of Fis values were negative and significantly different from zero, thus suggesting excess of heterozygosity. The microsatellite analysis showed low genetic differentiation among the populations (mean Fst = 0.044), which could be explained by the remarkable gene flow (Nm>1) among populations. |
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A. Ghasemi
,
M.H. Shirazi
,
R. Ranjbar
,
M.R. Khorramizadeh
,
N.E. Daryani
and
M. Hosseini
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The aim of this study was to investigate the prevalence
of cagA and cagE genes in H. pylori strains isolated
from different patient groups with Non-Ulcer Dyspepsia (NUD), Duodenal
Ulcer (DU), Gastric Ulcer (GU) and Gastric Cancer (GC). The patients admitted
to the gastroenterology unit at Sharyati hospital in Tehran in 2006 were
included in this study. Gastric biopsy specimens were obtained from the
antrum of the stomach from each patient then cultured for detection of
H. pylori. Identification of H. pylori was performed according
to the standard bacteriological methods. Genomic DNA was extracted using
a commercially available Qia gene kit. PCR was done using primers cagA-F,
cagA-R and cagE-F, cagE-R to detect the target genes cagA and cagE,
respectively. Amplified products of target genes were confirmed by sequencing.
The cagA and cagE were detected among 85 and 86% of H.
pylori isolates, respectively. Prevalence of cagA and cagE
genes in the patients with NUD, DU, GU and GC were 22 (64.7%), 28 (100%),
18 (90%), 10 (100%) and 25 (73.5%), 27 (96.4%), 19 (95%), 7 (70%), respectively.
The current study demonstrated a significant correlation between peptic
ulceration and the presence of H. pylori isolates carrying cagE
and cagA genes in Iranian patients. |
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A. Ghasemi
,
H. Jalilvand
and
S. Mohajeri Borazjani
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The purpose of this project was to asses ecological development of Avicennia marina in hyper saline condition. During 2001 and 2002 a restoration mangrove project planting A. marina in artificial inlet in Bushehr Province, Iran was carried out in Agriculture and Natural resources research center of Bushehr province in Sabkha lands. Some the vegetative characteristics of such as height, diameter and crown diameter in two aspects were recorded in 2012. To investigate physico-chemical properties of soil were taken in inside and outside of inlet and were analyzed: salinity, soil acidity, potassium, phosphorus, nitrogen, texture of soil were measured. Both of treatments were analyzed by t-test in SAS Software. |
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