Showing 6 results for ghorbanzadeh
Ghadir ghorbanzadeh, Gholamreza Rafiee, Soheil Eagderi, Hadi Poorbagher, Iraj Efatpanah,
Volume 3, Issue 2 (9-2014)
Abstract
The early morphological development and allometric growth pattern of Caspian kutum (Rutilus frisii kutum) during early development (from 0-35 days post hatch=dph) was studied. Morphological data were obtained using ImageJ software from 2D pictures and allometric growth patterns were computed based on Log10 y = Log10 α + βLog x function. Based on inflexion point of morphological traits and body shape changes, the early developmental of kutum were divided into Eleuthero-embryo, Propterygio-larval, Pterygio-larval” and younger juvenile phases, each of which included vital developmental events. Rapid and intense changes occurred during Eleuthero-embryo and Propterygio-larvae stages such as development of gills, depletion of yolk-sac and exogenous feeding, development of feeding apparatus, sense organs and organs related to swimming performance. The results also revealed that developmental changes occurred in agreement with the inflexion points of morphological characters and their developmental priority imply on functional importance of feeding, respiration and swimming related structures.
Volume 9, Issue 2 (Spring 2018)
Abstract
Aims: In recent years, magnetotactic bacteria and their magnetic nanoparticles (magnetosomes) were considered in different fields of science, including medicine, biotechnology, and nanobiotechnology due to their novel and unique magnetic properties. The present study was performed with the aim of evaluating the effect of temperature and reducing agent on labeling of magnetosomes with 188Re and biodistribution of labeled magnetic nanoparticles.
Materials and Methods: In this experimental study, Alphaproteobacterium MTB-KTN90 and sonication extraction method were used for the extraction of magnetic nanoparticles. After bacterial lysis, the magnetic nanoparticles produced by electron microscope were investigated and tin (II) chloride, as reducing agent, was used to check the labeling efficiency and rats were used to examine the biodistribution of the labeled magnetosomes.
Findings: The highest efficiency in magnetosome labeling experiments was 11100kBq in the initial activity, which decreased with increasing activity. The increase in temperature did not have much effect on increasing the labeling efficiency. The labeling value in the absence of a reducing agent was 721.5kBq, while at a concentration of 2mg of this agent, the labeling value increased to 10745.91kBq. After the injection of magnetosomes through the sublingual vein of the rat, the magnetosomes accumulated in the liver.
Conclusion: Magnetosomes extracted from Alphaproteobacterium MTB-KTN90 have a high potential for labeling by 188Re. Increasing temperature does not affect the labeling efficiency, but tin (II) chloride is a very important factor in optimizing the labeling efficiency, and the highest accumulation of magnetosomes labeled with 188Re after injection is in the liver of the rat.
Volume 13, Issue 12 (2-2014)
Abstract
Reorganizations of cyclic variations, depending on fuel type, equivalence ratio, engine load and speed, and engine geometry, are the major purposes and may cause fluctuations of output power and unburned hydro-carbon. During this study, the effects of gasoline and natural gas (NG) as fuel on cyclic variations were investigated utilizing the recorded cylinder pressure of a research SI engine over more than 400 successive cycles. This work was performed at full load, 1800rpm and compression ratio of 8 with 0.94 equivalence ratio using gasoline-air and NG-air mixtures. ُStatistical analysis of the obtained results showed that at the above conditions the coefficient of variations (COV) of indicated mean effective pressure (imep), peak pressure (Pmax) and the crank angle position of the peak pressure for gasoline-air mixture were 2.4, 1.29 and 1.04 times of those for NG-air mixture, respectively; at the optimum ignition timing, imep of gasoline-air mixture is increasing with rising Pmax and decreasing with enhancing , however, imep of NG-air mixture seems to be independent to Pmax and .
Volume 14, Issue 1 (FALL 2023)
Abstract
Production of drought tolerant crop is an important strategy for avoiding water scarce crisis. Improvement of the root structure leading to the higher yield and seed quality. In this study, three genes affecting root structure, drought tolerance and phosphorous absorbance are used in producing hybrid constructs used for the rice transformation. Three genes: a serine/threonine protein kinase (PSTOL1), a gene from the cytokinin oxidase/dehydrogenase family (OsCKX4) and a transcription factor induced under stress from the NAM-ATAF-CUC family (OsNAC5) isolated from the rice wild cultivars are cloned under separate regulatory elements in the T-DNA region of the Agrobacterium binary vector. OsNAC5 gene was cloned under RCc3 root specific promoter and PSTOL1 gene under ubiquitin promoter. Also, OsCKX4 gene was cloned once under ubiquitin promoter and once under RCc3 promoter. Two hybrid multi-gene constructs named pUhrN5CkPstol and pUhrCkPstol harboring multiple genes are synthetized and used for the gene transformation into the Hashemi cultivar. Gene transfer was done to callus obtained from mature rice seeds. Transgenic plants were confirmed using PCR analysis. From the number of 107 regenerated plants in which the presence of transgenes was proved, 14 transgenic events were finally obtained. Root structure of the T0 plants showed drastic phenotypic difference in comparison to the non-transgenic ones. By now, one transgenic event harboring CKX4 and PSTOL1 is confirmed to have a homozygous line in T2 generation. It is hoped that genetic engineering of rice for enhanced root structure lead to drought tolerance, reduce water consumption and improve yield under stress conditions.
Volume 16, Issue 1 (3-2016)
Abstract
In this study, a numerical method is used to investigate the effects convergence primary nozzle on the air ejector performance used in Polymer Electrolyte Membrane Fuel Cell (PEMFC). Simulations have been performed by solving the compressible form of two-dimensional Navier–Stokes equations. The turbulence model have been employed to estimate the turbulent region. A comparison of the computed results with the published experimental data exhibits agreement in terms of entrainment ratio at defined operating conditions. The ejector with convergence nozzle was widely used in the aerospace science, jet engine and Polymer Electrolyte Membrane Fuel Cell, because it has many advantages such as jet noise reduction, prevent condensation of water vapor inside the ejector and improvement of conventional converging-diverging nozzle. According to several applications and advantages of convergence nozzle, effects of primary converging nozzle on the flow characterization and the ejector performance have studied at any part of its. Based on particular application of the ejector with convergence primary nozzle in PEMFC, performance improvement is the purpose of this study. The results have been compared with air ejector with convergence-divergence primary nozzle. The results show that the air ejector performance has been enhanced under changing primary nozzle structure. This means that the ejector can consume available energy in its operation processes optimally beside increasing drawn secondary flow.
Volume 19, Issue 4 (April 2019)
Abstract
In this paper, heat transfer and magnetic fields in a vacuum induction melting furnace have been studied numerically. To solve the coupled equations of thermal and magnetic induction heating, the finite element method has been used. An induction furnace model is simulated using an industrial geometry. The studies indicate that the effect of the geometry of the crucible and the coil on the melting time has not been thoroughly investigated and requires more in-depth studies. It is attempted to improve the shape of the induction furnace, so that in less time aluminum is melted in a small scale furnace. The effect of the diameter-to-height ratio of the crucible on the duration of melting has been investigated. By decreasing the diameter-to-height ratio, the temperature reaches melting temperature in a shorter time. The results show that for the diameter-to-height ratio of less than 0.4, there will not be a significant change at the average temperature. 10% reduction in the distance between the coils leads to an increase in the average temperature of the working material inside the furnace. With considering the constant density of the coil current and the constant induced current in the heated material, the effects of the number of coil turns on the temperature distribution and magnetic flux are investigated. In this way, the accuracy of the model is also checked by induction heating concepts. The effect of frequency on temperature has been investigated in different coil lengths. The results show that an increase of 4 times in the frequency caused an increase of 1.7 times in the average temperature.
