فهرست مطالب

Sciences, Islamic Republic of Iran - Volume:28 Issue: 2, 2019
  • Volume:28 Issue: 2, 2019
  • تاریخ انتشار: 1398/08/22
  • تعداد عناوین: 9
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  • Sf. Miri, M.A. Tajick, H. Rahimian, G. Nematzadeh Page 105
    In this study, after identification of genes involved in biosynthesis of penicillin, we evaluated the expression of pcbAB and pcbC genes in P. Chrysogenum. A quantitative PCR (qPCR) approach was used to determine how these genes were expressed in different time courses. In addition, the produced penicillin content was measured using HPLC. qPCR analysis of mRNAs extracted from P. chrysogenum indicated that the expression levels of pcbAB, pcbC increased in seven days after inoculation compared to the expressed levels with others time courses, but this difference was not significant statistically. The analysis of chromatograms from injected showed that the highest content of penicillin in media observed in 7 days after cultivation, except in P. chrysogenum PTCC 5033. In addition, the results of comparative analysis among the tested strains showed that the penicillin content in 5, 7 and 11 days after cultivation was highest in P. chrysogenum PTCC 5037, P. chrysogenum PTCC 5031 and P. chrysogenum PTCC 5033, respectively. However, the results showed an evident relationship between the expression levels of penicillin biosynthesis genes and yielded penicillin.
    Keywords: Secondary Metabolites, Penicillin, gene expression, HPLC
  • F. Farzaneh, L. Jafari Foruzin, Z. Sharif, E. Rashtizadeh Page 113
    Bismuth oxide (Bi2O3) nanorods was prepared via one pot sol-gel method using Bi(NO3)3.5H2O and starch (as template) in water under hydrothermal condition followed by calcination at 320˚C within 3 h. The resultant solid product was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), thermogravimetry (TGA), and FTIR techniques. Based on the obtained results, the formation of Bi2O3 nanoparticles and nanorods at lower and higher percentage of starch is promising. It was found that Bi2O3 nanorods catalyse the aromatization of 1,4-dihydropyridines (DHPs) with 100% conversion and 100% selectivity.
    Keywords: Bi2O3 nanstructures, Hydrothermal synthesis, Aromatization, 1, 4dihydropyridines
  • M. Akhbari, S. Tavakoli, Z. Ghanbari, M. Dadgarnia, A. Mazoochi Page 119
    This study reports chemical composition of the essential oils and in vitro antioxidant, antimicrobial and cytotoxic activity of the volatile fraction, extracted using simulations steam distillation-solvent extraction (SDE) method, and methanolic extract from the stems and young leaves of Pterocarya fraxinifolia from Gilan, west-north of Iran for the first time. The extraction yield of volatile fraction from stems was about two times more than that of leaves. GC and GC/MS analysis of the stem oil, exhibited 44 components; the most abundant constituents was hexadecanoic acid. On the other hand,23 components were identified in the oil from leaves, with 3¸7-guaiadiene as the major components. The oils and extracts from both examined plant samples showed excellent antioxidant activities in 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC50 values
    Keywords: Pterocarya fraxinifolia, Essential oil analysis, Antioxidant activity, Antimicrobial activity, Brine shrimp bioassay
  • Moshafi M. H., N. Bahador, S. Moghimi, R. Ejtemaei, A. Foroumadi, Asadipour A. Page 127
    In this report, a new series of fluoroquinolone agents which was derived from levofloxacin was synthesized and evaluated against Gram-positive (Bacillus subtillis, Staphylococcus aureus, Staphylococcus epidermidis and Micrococcus luteus) and Gram-negative (Esherichio coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Serratia marcescens) organisms. The results showed that some of the synthesized compounds are strong antibacterial agents. All the synthesized compounds showed remarkable activities against Staphylococcus epidermidis and Staphylococcus aureus (MIC = 0.03-1 µg/mL and 0.06-1 µg/mL respectively).
    Keywords: Antibacterial evaluation, Fluoroquinolone, Levofloxacin
  • H. Atapour Page 133
    This paper documents the exploration significance of Ag/Au, Au/Cu, Cu/Mo and (Ag×Au)/Cu×Mo) ratios of the supra-ore and sub-ore halos versus fluid inclusion evolution for 24 Cu, 6 Cu- Mo and 10 Cu-Au porphyry deposits worldwide. The ratios are based only on the economic and mineralized hypogene alteration zones. The results indicate that (Ag×Au)/(Cu×Mo), Au/Cu and Cu/Mo ratios increase with decreasing depth and could be considered as the possible exploration guides for many as-yet- undiscovered unexposed porphyry deposits. These ratios are well correlated with vertical elemental vector zoning and alteration halos from the center (proximal potassic) outward (distal propylitic-zeolitic) and follow the order of Cu-Mo-Au, Cu-Zn, Zn-Pb-Ag, Ag-Pb- As-Sb-Hg-Au. On the basis of the (Ag×Au)/(Cu×Mo) ratios and fluid inclusion data, the Iranian continental arc porphyry copper deposits show multiphase halite-sylvite saturated fluid inclusions and formed between 2 to 4.75 km depth. The simple and multiple geochemical ratios and fluid inclusion evolution highlight that the Cu, Cu-Mo and Cu-Au porphyry deposits of the world were probably formed at
    Keywords: Geochemical ratios, Fluid inclusions, Depth of porphyry Cu, Cu, Mo, Cu, Au deposits
  • F. Khoshbakht, M. R. Rasaie, A. Shekarifard Page 147
    Proper determination of bed boundaries in layered reservoirs is vital ýfor accurate petrophysical interpretation of conventional logs. In the ýwellbore, logs continuously measure physical properties of reservoir ýwhile the properties change stepwise. This continuous representation ýof logs may lead to ignorance of some high potential reservoir zones. ýThe main reasons for continuous nature of logs in laminated reservoirs ýare the influence of shoulder beds on the reading of logging tools and ýlow vertical resolution of these devices.ýIn this paper we optimized a Laplacian filter to detect bed boundaries ýin conventional well logs. These blocking-based boundaries are ývalidated with FMI derived bed boundaries. Then the calculated ýpetrophysical properties including porosity and volume of minerals ýand fluids are distributed into the detected beds. Comparison of ýpetrophysical interpretation of logs based on blocking and FMI ýderived bedding showed that the petrophysical properties realistically ýdistributed into beds in layered reservoirs with the blocking technique. ýThe results also showed that blocking reduces the uncertainties, ýbecause it realistically distribute the petrophysical properties inside real ýgeological beds and alter the noises.ý
    Keywords: Bed boundary, Blocking, Image Log, Carbonate reservoir
  • M. Mortazavi Page 155
    Damavand is a fascinating dormant stratovolcano, 60 km to the ENE of Tehran located in the Alborz Mountains. Damavand volcanic products consist of lava flows and pyroclastic fall, flow and surge deposits from different eruption cycles. The volcanic rocks ranges from trachyandesite to trachyadacite and minor basalt. The mineral assemblage consists of potash feldspar (Or43/7), Plagioclase (An25 to An59), amphibole, clinopyroxene (augite and salite), orthopyroxene (hypersthene and ferro-hypersthene), biotite (phologophite) and Fe-Ti oxides. Some of the lavas and pyroclastic deposits show calc-alkaline affinities. Lavas from different cycled are classified as shoshonitic types and most pyroclastic deposits are classified as High-K. In comparison to n-type MORB, three recent pyroclastic deposits in Damavand show an enrichment in LREE, LILE, Th, and P and are slightly depleted in MREE and HREE. Incompatible LILE (Rb, Ba and Sr) together with Th and U have not shown broad enrichment as a function of increasing SiO2 content. Variations in the Major and trace element compositions of Damavand rocks and pyroclastic deposits are difficult to explain by fractional crystallization mechanism. Scatter of several trace elements in plots against SiO2 and incompatible trace elements, also suggests that the petrogenesis is more complex than a simple fractionation process from a single composition parent. High K, Ba and Rb content in volcanic products could be due to enrichment of these elements in the source. Field observation such as limitation of magmatism in region suggest that decompression melting could be generate the Damavand Lavas and pyroclastic deposits.
    Keywords: Damavand Pyroclastics, Damavand Volcano, Damavand lavas
  • H. Myrnouri Page 169
    We study certain function algebras and their operator algebra completions on r-discrete abelian groupoids, the corresponding conditional expectations, maximal abelian subalgebras (masa) and eigen-functionals. We give a semidirect product decomposition for an abelian groupoid. This is done through a matched pair and leads to a C*-diagonal (for a special case). We use this decomposition to study the norm-one eigenvectors of corresponding full C*-algebra instead of the multiplicative functionals (spectrum) which have norm-one in the abelian group case.
    Keywords: Decomposable groupoid, Abelian groupoid, Dual groupoid, Eigen, functional
  • A. Eskandari, Asl Page 175
    The one photon absorption (OPA) cross section of a current carrying two-orbital quantum dot (QD) with strong electron-phonon interaction (polaron regime) is considered. Using the self-consistent non-equilibrium Hartree-Fock (HF) approximation, we determine the dependence of OPA cross section on the applied bias voltage, the strength of effective electron-electron interaction, and level spacing of QD. Our numerical results reveal a unique property that there are two distinct regimes for OPA. We find that for values of level spacing of QD smaller than half the strength of effective electron-electron interaction and all values of applied bias voltage, the absorption is due to the excitation of the plasmon modes of the system with low cross section, but for the values of level spacing larger than the aforementioned value, within a finite range of the applied bias voltage, set by the values of level spacing and the strength of electron-electron interaction, the OPA is due to electron transition between the two orbitals of QD with an order of magnitude larger cross section than the former case. This property results in an almost square shape cross section as a function of applied bias, for peak values of absorption at resonance frequencies.
    Keywords: Two, orbital Quantum dot, Polaron regime, Bias, induced absorption, OPA cross section