2024-03-28T19:00:01Z
https://scientiairanica.sharif.edu/?_action=export&rf=summon&issue=266
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
Spectroscopic and Thermodynamic Studies of Interaction Between Dopamine and Cobalt(III) Schi-Base Complexe
D.M.
Boghaei
In this paper, the interactions of cobalt(III) tetradentate Schi-base complexes, [Co(3-
MeO-salophen)]ClO4, (1), [Co(5-NO2-salophen)]ClO4, (2), and [Co(5-Br-salophen)]ClO4, (3), with
dopamine, an important neurotransmitter, have been investigated. The formation and kinetic constants for
complex formation of [Co(3-MeO-salophen)]ClO4, (1), with dopamine were determined spectrophotometrically
in H2O/EtOH solution (4:1) at 30 C by using the Benesi-Hildbrand and Guggenheim equations,
respectively. The stoichiometry has been found to be 1:1. The rate and equilibrium constants for the
coordination of dopamine to [Co(3-MeO-salophen)]ClO4 were found to be 0.0053 min????1 and 1600 dm3
mol????1, respectively.
Cobalt(III) Schi-base complexes
Dopamine
Benesi-Hildbrand equation
Guggenheim's method
Neurotransmitter
2009
12
01
https://scientiairanica.sharif.edu/article_3265_001e6109bafa3422e392c8892a376ff4.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
DFT Study of the Interaction of Thymine with Cu+ and Zn2+
A.
Fattahi
M.
Shakorian Fard Jahromi
Interaction of the DNA thymine base with Cu+ and Zn2+ was studied to explore: a) The
metal binding energy (MIA) of thymine with Cu+ and Zn2+ and b) The possible correlation between
charge transfer and MIAs. The gas-phase Cu+ and Zn2+ anities of thymine, as well as the Mulliken
charges, on the complexed metal cations were both determined at the same computational level, including
the density functional level and employing the hybrid B3LYP exchange correlation potential in connection
with the 6-311++G (d; p) basis set. All the molecular complexes were obtained by interaction between the
most stable tautomer of thymine and two transition mono and divalent (Cu+, Zn2+) metal ions. To probe
all possible binding sites, these two cations were placed around the thymine nucleobase and optimized. For
both Cu+ and Zn2+, the complexes of thymine with O4 are the most stable structure. For complexes of
thymine with mono cations (Li+, Na+, K+ and Cu+) and dications (Mg2+, Ca2+ and Zn2+), the results
indicate a linear correlation between the transferred charge and metal binding energy. The results also
indicate that the amount of charge transfer and bonding strength are the highest for the transion metal
ions Cu+ and Zn2+, respectively.
Divalent cations
Metal ion anity
Thymine
Metal complexation
Charge transfer
2009
12
01
https://scientiairanica.sharif.edu/article_3266_49a6897c0dccc9ebe07bb8675c84cc8c.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
Superheated Water Extraction of Catechins from Green Tea Leaves: Modeling and Simulation
I.
Goodarznia
A.
Abdollahi Govar
Catechins from fresh green tea leaves as potential sources of anticancer and antioxidant
components were target materials in this work. Superheated water extraction, which is a kind of leaching
operation, and solvent partition with chloroform and ethyl acetate were utilized to recover Catechins
from tea leaves. Then, a mathematical model was developed to simulate the superheated water extraction
of Catechins. The unsteady state mass balance of the solute in solid and superheated water phases
led to two partial dierential equations. The model was solved numerically using a linear equilibrium
relationship. The model parameters were predicted applying existing experimental correlations. An
intraparticle diusion coecient was used as the model tuning parameter. The model is able to show
the in
uence of dierent process parameters, such as time of extraction, particle size and the ratio of
water/leaves (v/w), on Catechin recovery.
Superheated extraction
modeling
Mass transfer
Diusion
Catechins
2009
12
01
https://scientiairanica.sharif.edu/article_3267_ab0805531581e6e20e93f335d174a15a.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
Application of Cyclic Steam Stimulation by Horizontal Wells in Iranian Heavy Oil Reservoirs
S.D.
Razavi
R.
Kharrat
In Iran, there are a number of heavy oil reservoirs whose importance is growing as the
conventional resources deplete. This study concerns the numerical simulation of cyclic steam stimulation
of one of the heavy oil reservoirs. Results are encouraging and should be tested by eld pilots. Heavy oil is
characterized by its high viscosity. Thermal methods reduce viscosity and residual oil saturation to improve
mobility and achieve an economical recovery. Cyclic Steam Stimulation (CSS) which has faster production,
lower capital costs and lower pressure operations than steam-
ooding is of great interest in thermal
methods. Oil recovery with steam injection has been enhanced with horizontal wells by increasing sweep
eciency, the contact area opened to
ow, producible reserves, steam injectivity and also by decreasing the
number of wells required so that higher oil production is reached. K-Field is one of the Iranian fractured
heavy oil elds with low API of 7.24 and high viscosity of 2700 cp. Although steam injection in naturally
fractured heavy oil reservoirs provides extremely challenging issues, it can be considered as a potentially
eective and ecient improved recovery method. In this study, using STARS, a thermal dual-porosity
model was constructed based on the available measured data to study CSS. Comprehensive and comparative
studies and a sensitivity analysis of various operational parameters were conducted in order to nd the
optimum conditions for a high RF. This work shows that oil recovery could be improved from 0.66% by
cold production to more than 10% by CSS during a 10 year period.
Heavy oil
Enhanced oil recovery
Thermal methods
Steam injection
Cyclic steam stimulation
Horizontal well
2009
12
01
https://scientiairanica.sharif.edu/article_3268_c0e17357a344ed103b2f6da83d1a477f.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
Production of Chitosan by Submerged Fermentation from Aspergillus niger
S.
Yaghmaei
V.
Maghsoodi
J.
Razavi
The eect of glucose concentration in submerged fermentation (SMF) on chitosan
production by Aspergillus niger was investigated. A. niger, BBRC, 20004, from the Biochemical and
Bioenvironmental Research Centre at Sharif University of Technology, Tehran, Iran, was grown in a
Sabouro Dextrose media. Chitosan was extracted from the fungal mycelia using hot alkaline and acid
treatment and after 12 days of cultivation, 0.8455 g chitosan /l of the fermentation medium was obtained.
The content of glucose in the Sobouro Dextrose Broth media was also changed and the highest yield of
chitosan 0.9121g/l was obtained in Sobouro Dextrose Broth media containing 8% glucose.
Chitosan
Aspergillus niger
Submerged fermentation
Sabouro Dextrose Broth media
Glucose
2009
12
01
https://scientiairanica.sharif.edu/article_3269_c74b21e07952f940b51d9c438555406a.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
A New Eco-Friendly and Ecient Mesoporous Solid Acid Catalyst for the Alkylation of Phenols and Naphthols Under Microwave Irradiation and Solvent-Free Conditions
F.
Matloubi Moghaddam
M.
Akhlaghi
L.
Hojabri
M.G.
Dekamin
The catalytic activity of a mixture of ZnCl2: AlCl3 supported on silica gel was evaluated for
the alkylation of phenols with benzyl alcohol, tret-butyl alcohol and styrene under microwave irradiation
and solvent-free conditions. The catalyst preparation method, its characterization and reusability, were
reported. The eect of the phenol to benzyl alcohol ratio and the time of reaction on the phenol conversion
and distribution of products was investigated. A conversion percentage up to 97% was achieved when
hydroquinone was used. A selective ortho- directed alkylation for phenol, -naphthol and -naphthol was
observed.
Mesoporous solid acid catalyst
Alkylation
Phenols
Microwave irradiation
Solvent free
2009
12
01
https://scientiairanica.sharif.edu/article_3270_06a1fecd245c2a7f63c5db91a9499161.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
Highly Ecient One-Pot Three-Component Mannich Reaction Under Solvent-Free Conditions
N.
Azizi
M.R.
Saidi
F.
Ebrahimi
A mild and practically-convenient one-pot procedure for the direct Mannich reaction has
been developed using a condensation of amines, aldehydes and unmodied ketones under solvent free
conditions in the presence of ZnI2 with good to excellent yields. The present methodology oers several
advantages, such as excellent yields, simple procedures, short reaction times and milder conditions with
very small amounts of catalyst. Furthermore, it is the rst time that the catalytic activity of several
catalysts under solvent free conditions has been studied. It was found that both the diastereoselectivity
and the rate of reaction were improved with various Lewis acids and metal oxides. However, the chiral
catalysts, such as L-cystine, (-)-cinchonidine and L-proline, did not work well in terms of yield and
diastereoselectivity under this condition.
Amine
aldehyde
Catalyst
Maanich reaction
Solvent-free
2009
12
01
https://scientiairanica.sharif.edu/article_3271_592f60adb7d3ba9f7511cf6eb6609ccd.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
An Improved Procedure for the Enrichment of Plasma F2-Isoprostanes Prior to Final Determination by GC-MS/NICI
J.
Nourooz-Zadeh
One of the most popular approaches to quantify oxidative injury is to measure lipid
peroxidation products and, in particular, F2-isoprostanes (F2-IPs). F2-IPs is a group of prostaglandin
F2-like compounds derived from the non-enzymatic oxidation of arachidonic acid. Of these, the
15-F2t-isoprostane (8-iso-PGF2) has received considerable attention, because it possesses adverse
biological activities. Previous Gas Chromatographic-Mass Spectrometric (GC-MS) methods for measuring
plasma F2-IPs from this laboratory involved two chromatography steps on C18 and NH2-cartridges.
Problems may, however, arise with chromatography on C18 cartridges, as it can be time-consuming
and losses may occur depending upon the pH and eciency of the sample loading. Therefore, it was
decided that the C18 chromatography step be replaced with a single lipid partitioning step and the
NH2-chromatography be simplied. In 70 plasma samples from healthy individuals, total (sum of free and
esteried) 15-F2t-isoprostane concentrations ranged from 0.5 to 3.13 nM. This assay meets all predened
method performances in terms of specicity and sensitivity. The improved method is suitable for the
analysis of samples from larger clinical trials investigating the role of oxidant injury under conditions
associated with oxidative stress.
One of the most popular approaches to quantify oxidative injury is to measure lipid
peroxidation products and, in particular, F2-isoprostanes (F2-IPs). F2-IPs is a group of prostaglandin
F2-like compounds derived from the non-enzymatic oxidation of arachidonic acid. Of these, the
15-F2t-isoprostane (8-iso-PGF2) has received considerable attention, because it possesses adverse
biological activities. Previous Gas Chromatographic-Mass Spectrometric (GC-MS) methods for measuring
plasma F2-IPs from this laboratory involved two chromatography steps on C18 and NH2-cartridges.
Problems may, however, arise with chromatography on C18 cartridges, as it can be time-consuming
and losses may occur depending upon the pH and eciency of the sample loading. Therefore, it was
decided that the C18 chromatography step be replaced with a single lipid partitioning step and the
NH2-chromatography be simplied. In 70 plasma samples from healthy individuals, total (sum of free and
esteried) 15-F2t-isoprostane concentrations ranged from 0.5 to 3.13 nM. This assay meets all predened
method performances in terms of specicity and sensitivity. The improved method is suitable for the
analysis of samples from larger clinical trials investigating the role of oxidant injury under conditions
associated with oxidative stress.
F2-isoprostanes
Lipid peroxidation
Oxidative stress
Gas chromatography-mass spectrometry
2009
12
01
https://scientiairanica.sharif.edu/article_3272_a7d41ba18e923923c308e004a69165c7.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
Investigation and Selection of Suitable Layers in Bangestan Reservoir for Hydraulic Fracturing Operation
S.R.
Shadizadeh
B.A.
Habibnia
R.
Syllabee
Hydraulic fracturing is a process applied to boreholes to improve the ability of
uids (such
as oil and gas) to
ow to the hole and be recovered. Recent investigation has shown that fractures can
play a major role in the productivity of low permeability formations. The Ahwaz oil eld is one of the
largest in South West Iran. The Bangestan reservoir in this eld, with a suitable amount of oil in place
and good rock reservoirs, has been selected for the present research work. The pressure prole has been
calculated in tight reservoirs in a few wells, for the purpose of hydraulic fracturing operation studies. In
this work, the pore pressure was calculated by using the available eld data in the carbonated reservoir
of the Ahwaz eld. The results indicate that the Ilam formation could be a good candidate for hydraulic
fracturing.
Hydraulic fracturing
Minimum horizontal stress
Stress gradient
Bangestan reservoir
2009
12
01
https://scientiairanica.sharif.edu/article_3273_b7acfee07e806f002eccd5fab742c88f.pdf
Scientia Iranica
Scientia Iranica
1026-3098
1026-3098
2009
16
2
Mathematical Modeling of a Non-Catalytic Gas-Solid Reaction: Hematite Pellet Reduction with Syngas
M.S.
Valipour
A mathematical model is developed to investigate the nonisothermal reduction of the
hematite pellet with Syngas, namely is a mixture of hydrogen, water vapour, carbon dioxide and carbon
monoxide gases. This model is based upon special application of the grain model and contains the
interactions between Syngas and the hematite pellet as a re
ection of the heat and mass transfer phenomena.
Each grain is reduced as an un-reacted shrinking core model at three interfaces simultaneously.
A concluded set of equations is solved using the nite volume approach as an implicit formulation. Finally,
the model was applied to study the isothermal and non-isothermal reduction of the hematite pellet and
investigate the eects of Syngas characteristics, like gas utility ((CO+H2)/(CO2+H2O)) and gas ratio
(H2/CO), on the rate of reduction.
Mathematical modeling
Gas-solid reaction
Direct reduction iron
Hematite pellet
Kinetics
2009
12
01
https://scientiairanica.sharif.edu/article_3274_6b27e78d914ba8e032c3a58da5168cf5.pdf