eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31369
SHOOT REGENERATION FROM PROTOPLASTS
OF PENNISETUM AMERICANUM L
(MIL CEREAL)
A finely dispersed cell suspension was obtained from embryogenic calli of
two genotypes of pearl millet (Pennisetum americanum L. Mil cereal). Protoplasts
isolated from both cell suspensions divided and produced globular embryoids
and calli. On an agar medium, the embryoids were induced to form
albino shoots or albino plantlet- like structures
https://jsciences.ut.ac.ir/article_31369_155a10eb07101ff4a71f4208f6b376ee.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31370
THERMODYNAMIC STUDIES ON THE
INTERACTION BETWEEN DODECYL
TRIMETHYL AMMONIUM BROMIDE AND
HISTONE H A
The thermodynamic parameters of interaction between calf thymus histone
H A and dodecyl trimethyl ammonium bromide (DTAB), a cationic surfactant,
in aqueous solutions of pH 3.2, 6.4 and 10.0 were measured over a wide range
of DTAB concentrations by equilibrium dialysis at 27°C and 37°C and are
discussed. The data are used to determine the free energy from the Wyman
binding potential theoretical model, and the enthalp y of interaction from the
temperature dependence of the equilibrium constants using the van't Hoff relation.
The data obtained for H A-DTAB are compared with the corresponding
data for H A and sodium n-dodecyl sulphate (SDS) complexes. The difference
between the cationic and anionic surfactants interaction in regard to histone
H A is discussed
https://jsciences.ut.ac.ir/article_31370_6c027be6135a7f4b86806067124e1f2f.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31371
A MODEL FOR THE BASIC HELIX- LOOPHELIX
MOTIF AND ITS SEQUENCE SPECIFIC
RECOGNITION OF DNA
A three dimensional model of the basic Helix-Loop-Helix motif and its
sequence specific recognition of DNA is described. The basic-helix I is modeled
as a continuous ?-helix because no ?-helix breaking residue is found
between the basic region and the first helix. When the basic region of the two
peptide monomers are aligned in the successive major groove of the cognate
DNA, the hydrophobic side chains of the helix I-helix I come in van der Waals
proximity. In this way, the end residues of the helix I-helix I are placed far
from each other so that a "loop" is needed to bring the helix II-helix II close
together for hydrophobic interactions and therefore dimerization. The proposed
sequence specific recognition is by hydrogen bonding of the conserved Asn (or
Thr) and Glu side chains to the consensus guanine and adenine respectively.
The methyl group of Thr and the hydrophobic residue next to it also produce a
hydrophobic pocket for recognition of the methyl group of the consensus thymine.
The highly conserved Arg's interact with backbone phosphates and a direct
recognition of base pairs by Arg's is not likely
https://jsciences.ut.ac.ir/article_31371_7605b47d1eb4678854cbb707716c990b.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31372
A STUDY OF THE ANTHELMINTIC ACTIVITY
OF AQUEOUS EXTRACT OF PLEUROTUS
ERYNGII ON SYPHACIA OBVELATA AND
HYMENOLEPIS NANA
Pleurotus eryngii is a mushroom growing in the Bakhtiari province of Iran
and is known as a mountain fungus. The fresh fungus is used as a food, and
when dried its powder has been used as an anthelmintic drug. We decided to
study the anthelmintic activity of P. eryngii on Hymenolepis nana (cestode) and
Syphacia obvelata (nematode), using experimental animals. Water extract of P.
eryngii was prepared by the maceration method. White mice (Suri) laboratory
bred were infected with H. nana worms. Four concentrations of aqueous extract
of the fungus (484.5,800,900 and 1500 mg fungus/ml) were fed three times to
the infected mice. The anthelmintic effects of the aqueous extract of the fungus
on S. obvelata were also studied in the infected animals using the same procedure.
The results of the study indicated that the highest anthelmintic effects of
the fungus on H. nana and S. obvelata were 89% and 95%, respectively
https://jsciences.ut.ac.ir/article_31372_a5c6f7b030ec2985564e7256e3a27c41.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31373
AN NMR STUDY OF IONIC SOLVATION OF
ALKALINE EARTH CATIONS WITH
DIMETHYLSULFOXIDE IN NITROMETHANE
SOLUTION
A proton NMR method for the determination of the solvation numbers of
alkaline earth cations with dimethylsulfoxide (DMSO) in nitromethane as
diluent is described. The method is based on the monitoring of the resonance
frequency of DMSO protons as a function of DMSO to metal ion mole ratio
while keeping the metal ion concentration constant. The average solvation number
of cations at any DMSO/metal ion mole ratio was calculated from the
NMR chemical shift mole ratio data and was plotted against the mole ratio
values. The solvation numbers of alkaline earth cations were extracted from the
limiting values of the corresponding ii-mole ratio plots and were found to be 6
for Ba ,sr an d ca i ons and 5 for Mg ion . Effect of the presence of water
on the solvation numbers of alkaline earth cations with DMSO was studied. In
this case, the variation in the resonance frequency of H 0, brought about upon
titration of the cations by DMSO, was also used to estimate the solvation
number of cations with DMSO
https://jsciences.ut.ac.ir/article_31373_78235abf9160fc94ca9177b657c05fbf.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31374
REACTION OF QUINONEIMINES WITH
KETENES
The reactivity of quinoneimines towards ketene and diphenylketene was examined.
N-Phenylbenzoquinoneirnines (I), (2) and also N-phenylnaphthoquinoneimine
react with ketene to give the spiro-adducts (5), (7) and (1 1) respectively.
These adducts were stable even after prolonged heating in high boiling
solvent. Reaction of the above imines with diphenylketene also afforded 13-
lactam spiro-adducts (6), (8) and (12), but they rearranged to oxindole derivatives
(9), (10) and (13) by heating in boiling ethanol. N-Phenyl-9, 10-
anthraquinoneirnine, however, was inert towards ketene or diphenylketene under
the same reaction conditions
https://jsciences.ut.ac.ir/article_31374_9b7c2123c5aa44d537aa422d7096ade8.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31375
GAS-PHASE ACIDITY OF SOME CARBOXYLIC
ACIDS CALCULATED BY MNDO
Gas-phase acidities of 15 aliphatic carboxylic acids, X CH -,COOH, have
been calculated using the MNDO method. Among the substituted groups exist
the electron donor alkyl groups and electron acceptor halogens. The average
error in acidity is within the experimental uncertainty of the data. Systematic
errors have been found for the substituents which form internal hydrogen
bondings. A reasonable correlation does exist between the gas-phase acidity
and the net atomic charges on the acidic hydrogens in the neutral form and the
net atomic charges and ionization potentials of the anions. There is no correlation
between the gas-phase acidity and HOMO and bandgaps
https://jsciences.ut.ac.ir/article_31375_c8e8948b8dbc485a7df191d5a3abcfb9.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31376
A NOVEL METHOD FOR SYNTHESIS OF
NAPHTHOFURANS AND NAPHTHODIFURANS
Thermal rearrangement of propargyl naphthyl ethers produced naphthopyrans.
In the presence of sodium methoxide, propargyl naphthyl ethers were
converted easily to naphthofurans and naphthodifurans in good yields
https://jsciences.ut.ac.ir/article_31376_00872b058ce6bf0721aee191bdd75876.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31377
THE KINETICS OF HYDROLYSIS OF
TRANS-DIFLUOROTETRAMMINECHROMIUM
(111) ION IN VARIOUS
CONCENTRATED ACID SOLUTIONS
The rate of hydrolysis of trans -[Cr(NH ) F ] was obtained as a function of acid
concentsation in perchloric, sulfuric and nitric acid at 3Q°C. The results have been
analyzed by the treatment of Bunnett and Olsen. Values of the parameter ?in Olsen
equation are consistent with the participation of water as a proton-wansfer agent in the rate-determining step. The Arrhenius plot for perchloric acid was linear, with an
activation energy of 19.8 ± 0.8 KCal K mole .
https://jsciences.ut.ac.ir/article_31377_5d0e7b7f79a5402a1bcfe8e9f43536fc.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31378
MODELING THE STOCHASTIC BEHAVIOR OF
THE FARS RIVERS
Historical records for rivers in Fars Province are inadequate in comparison
with the design period of hydraulic structures. In this study, time series
techniques are applied to the records of three Iranian rivers in the Fars Province
in order to generate forecast values of the mean monthly river flows. The
autoregressive models (AR), moving average models (MA) and autoregressive
moving average models (ARMA) are fitted to the stationary series and the
optimum model for each river is formulated. Data generation is done and the
synthetic sequences are tested individually against the corresponding historical
data, and the optimum length of synthetic data is specified. Statistical tests
including means, standard deviations, spectral diagrams and Hurst's coefficient
are also provided
https://jsciences.ut.ac.ir/article_31378_520b6650d579b6c594356c4fac76509b.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31379
BATCH TRANSFERRING IN PRODUCTIONINVENTORY
SYSTEMS
In most production-inventory systems, the products are transferred from the
production centre to the inventory (warehouse) in subbatchs rather than one at a
time. In this paper, mathematical models of such systems for both deterministic
and stochastic cases of demand are developed and analysed. Comparison of
these new models with the EBQ model shows a considerable loss when applying
the rules of EBQ model to the batch transferring systems.
https://jsciences.ut.ac.ir/article_31379_9b75a1d40a74134ed19ed337d7d68129.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31380
IDEAL J *-ALGEBRAS
A C *-algebra A is called an ideal C * -algebra (or equally a dual algebra) if it
is an ideal in its bidual A**. M.C.F. Berglund proved that subalgebras and
quotients of ideal C*-algebras are also ideal C*-algebras, that a commutative
C *-algebra A is an ideal C *-algebra if and only if it is isomorphicto C (Q) for
some discrete space ?. We investigate ideal J*-algebras and show that the
above results can be generalized to that of .I*-algebras. Furthermore, it is
proved that if A is an ideal ,J*-algebra, then sp(a* a) has no nonzero limit point
for each a in A and consequently A has semifinite rank and is a restricted
product of its simple ideals
https://jsciences.ut.ac.ir/article_31380_9d9445565a925df07e365566e8e4ea9d.pdf
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
1994-06-01
5
1
31381
KINETIC STUDY OF TRR CORE IN FUEL
CONVERSION FROM HEU TO LEU
In the conversion of fuel in the Tehran Research Reactor core from Highly-
Enriched Uraniutn to Low-Enriched Uranium fuel neutronics analysis, thermal
hydraulic calculations and kinetic performance of the core have to be studied.
In this study, static and dynamic core performance for HEU and LEU fuels
were investigated. In static conditions, two groups of neutron flux distributions
in axial direction were obtained by solving diffusion equations. In transient
cases, the slow and fast transient phenomena, small reactivity and large reactivity
insertion effect, were investigated. To find the temperature feedback effect
on core reactivity, such as coolant drainage tnalfunction, the effective tnultiplication
factor was calculated for two different temperatures, namely 293? K and
373? K, using the cotnputer code WIMS-D/4. From here, the average temperature
coefficient of reactivity was obtained. It should be pointed out that the
coefficient dependence on temperature is approximately a linear function. In
fast transient study, for HEU fuel $1.510.5 reactivity and for LEU fuel $1.3510.5
reactivity were considered. In slow transient study, a reactivity equivalent to
$0.0085/s for HEU fuel and $0.0034/s and $0.00851~ in the case of LEU fuel
was introduced into the core. The result of calculations show that in fast transient
in the case of LEU fuel, reactor power drops sharply before the scram time
set is reached. It seems as if the overall performance of the LEU core is comparable
with that of the HEU fuelled core
https://jsciences.ut.ac.ir/article_31381_380f6aeba6df4de5d88fd556c037a10f.pdf