University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
NUMERICAL TAXONOMIC STUDY OF THE
IRANIAN SPECIES OF ALYSSUM L. BASED ON
MORPHOLOGICAL CHARACTERS
-
31112
EN
Journal Article
1970
01
01
The genus Alyssum L. belongs to the subtribe Alyssinae, tribe Alysseae and family
Cruciferae (Brassicaceae). This genus is one of the largest genera of the family of
Cruciferae in Iran, and seems to be the most problematic genus in which the boundary
of certain species is not completely clear due to the polymorphism of morphological
characters. The main objective of this research is to study the species of the genus
Alyssum using numerical taxonomic methods. Thirty-three Operational Taxonomic
Units (OTUs) belonging to the twenty-nine species of Alyssum L. from Iran were
examined and scored for thirty-six qualitative characters having two or more states.
This work is based on field and different herbarium samples. The data were analysed
by UPGMA clustering method. The results of this study suggest that there are
basically four sections (Meniocus, Odontarrhena, Alyssum and Psilonema) which
can be grouped under two subgenera, namely subgenus Eualyssum and subgenus
Meniocus. The results of cluster analysis were compared with the classification
obtained by conventional methods and the relations among the taxa have been
discussed
https://jsciences.ut.ac.ir/article_31112_630ca2eb14f88fcb3172fc6fb16647ad.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
THE EFFECTS OF SALT STRESS ON THE SHOOT
APICAL MERISTEM AND LEAF GENIERATION IN
SUNFLOWER (HELIANTNUS ANNUUS L.)
-
31113
EN
Journal Article
1970
01
01
Sunflower (Helictnthur annuus L. cvs Mehr Shafagh) seedlings were grown in
nutrient solutions containing 20.5 to 70.4 mM NaCl and 0 as the control. The effects
of salinity on developmental changes occurring in the shoot apices of plants were
studied. At 20.5 mM NaCI concentration, the leaf emergence rate and plastochron
index of Shafagh increased significantly, but this phenomenon was not observed in
Mehr. These parameters decreased in 41 mM and higher salt concentrations. In
Shafagh plants, anatomical changes in shoot apical meristem at 20.5 mM NaC1
consisted of the meristem and increased density and chromophilly in rneristem cells,
which are indicators of stimulated mitosis, pitrticularly in the peripheral zone. No
changes were observed in Mehr. In both cultivars, 41 mM and greater NaCl
concentrations led to an increase in the width of meristems, uniform chromophilly of
cells and dispersed mitotic activity. These phenomena are assumed to be signs of the
transformation of a vegetative apical meristem into a reproductive one. The leaf
segments shortened and xylem differentiation was seen nearer to the apex. The shoot
apical meristem of Shafagh cultivar plants at 20.5 mM NaCl appeared to be activated
for leaf generation. The effect of high salt concentrations on precocious flower
formation of sunflower is also discussed
https://jsciences.ut.ac.ir/article_31113_653eda0715c931e940f0b31ba8f0a318.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
THE STUDY OF CHROMOSOMES AND
SOLUBLE PROTEINS IN FOUR SPECIES OF VINCA (V.ROSEA, V. MAJOR , V. MINOR, V.HERBACEA) GROWN IN IRAN
-
31114
EN
Journal Article
1970
01
01
Indole ahloids of Vinca species are valued greatly in medical sciences, one
reason being for their use as powerful anticancer agents. There are four species of
Vinca in Iran: V. rosea, V. major, V. minor and V. herbacea. In previous
investigations, we found that these plants have considerable alkaloid similarity (58.8- 75%). Therefore, chromosomic and electrophuretic studies followed after investigation. We tried to provide exact chromosome numbers and karyotypes of Vinca plants by using acetocarmine and Feulgen staining procedures. Diploid numbers of V. rosea,V. major, V. minor and V. herbacea were 16,64,46,46, respectively. The observed number for V. major, with one exception, was different fkom existing reports. In fact , we had a new cytotype of this species in Iran. Vinca plants were also compared with each other electrophoretically. The SDS-PAGE of total proteins was provided and their dendrogram was drawn. The results showed that V. rosea, V. herbacea and V minor resemble one another cbsely. In general, it can be concluded that V. major on the one hand and V. minor and V. herbacea on the other may have originated from V.rosea species.
https://jsciences.ut.ac.ir/article_31114_1adb0297b4b87091af68d01f276e3c4e.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
POLAROGRAPHIC AND POTENTIOSTATIC
REDUCTION OF CARBODIIMIDES:
A MECHANISTIC STUDY
-
31115
EN
Journal Article
1970
01
01
The polarographic reduction of aromatic carbodiimides in anhydrous aprotic
solvents goes through a carbene intermediate by a diffusion controlled process in two
one-electron steps. The first step is the rate-determining step and converts the
carbodiirnide to a radical anion (6) that reduces further by a fast one-electron step to
a carbene dianion intermediate (7). This abstracts an oxygen, along with protons,
from the solvent to give diphenyl urea (9) or reduces further to methylene dianiline
(12) .
https://jsciences.ut.ac.ir/article_31115_463d94080e3c9aa9ac65a38b7140113b.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
ELECTROCHEMICAL BEHAVIOR OF GC, Pt
AND Au ELECTRODES MODIFIED WITH THIN
FILM OF COBALT HEXACYANOFERRATE
-
31116
EN
Journal Article
1970
01
01
0A thin film of cobalt hexacyanoferrate (CoHCF), an analogue of mixed-valence
Prussian blue, was deposited electrochemically on the glassy carbon, platinum and
gold electrode surfaces in 0.5M KC1 solution. The electrochemical behavior of these modified electrodes show three couples of redox peaks by CV in a supporting
electrolyte solution of 0.5M NaCl, whereas for Au modified electrode only one
couple of redox peaks is observed because of self-oxidation of gold substrate at more
positive potentials. The effect of various factors such as cations and anions of
supporting electrolyte, solution pH, scan rate and the limit of sweeping potential on
the CV response of modified electrodes was also studied. It was shown that the
electrodeposited CoHCF film is stable for several days, whether stored at open circuit
in a 0.5M KC1 or NaCl supporting electrolyte or in air
https://jsciences.ut.ac.ir/article_31116_861ffb30f3ca3cb5eaee1160a624f7a6.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
SYNTHESIS AND CHARACTERIZATION OF
AMINE(CHLOR0)COBALOXIME DERIVATIVES.
APPROXIMATE VALUES OF THE ANGULAROVERLAP
PARAMETER, ?, FOR THE
COORDINATED AMINES
-
31117
EN
Journal Article
1970
01
01
Four new complexes of the type [LCo ((DO)(DOH) pn) Cl] PF , where (DO)
(DOH) pn = N , N '- propanediylbis (2, 3-butanedione2-imine3-oxirne)a nd L =morpholine (mrpln) (I), benzylamine (bzlan) (II), piperidine (pprdn)(III) and pyrrolidine (prldn) (IV) have been synthesized and characterized by elemental analyses and spectroscopic methods. Approximate values of the angular-overlap parameter, ?, for the coordinated amines are estimated to be: 6395,6627,6797, and 7076 cm for mrpln, bzlan, pprdn, and prldn, respectively
https://jsciences.ut.ac.ir/article_31117_1e0bae7c580317de0aa8a614d0fde12d.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
REACTION OF VINYLENE
TRITHIOCARBONATE WITH
CHLOROSULFONYL ISOCYANATE
-
31118
EN
Journal Article
1970
01
01
The reaction between vinylene trithiocarbonate and chlorosulfonyl isocyanate
proceeds by initial attack of thiocarbonyl on the isocyanate carbon.
https://jsciences.ut.ac.ir/article_31118_e8137e834d5ff09c7a2cce61b1e7916e.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
ISOLATION AND STRUCTURAL ELUCIDATION
OF THE FIRST KNOWN
C-HOMOPROTOBERBERINE
-
31119
EN
Journal Article
1970
01
01
A novel C-homoprotoberberine alkaloid, Hediamine (2), has been isolated from
the roots of Berberis actinucantha (Berberidaceae). Conclusive proof for the structure of hediamine was obtained by its comparison with the isomeric lactam (4), by chemical transformation, and by means of spectroscopic techniques (UV, IR, MS,
NMR).
https://jsciences.ut.ac.ir/article_31119_4078c51346aabd9b308afdd63a29b2a6.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
SIMPLE DERIVATION OF FRANCK-CONDON
INTEGRALS
-
31120
EN
Journal Article
1970
01
01
The expressions foavibrational overlap integrals of the one-dimensional harmonic
wavefunctions (centenxi about different equilibrium positions and having different
frequencies) have been derived in a simple and straightforward way.
https://jsciences.ut.ac.ir/article_31120_92d3b7cbc94b8f08af8245647a0966bc.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
ON OPTIMAL NOZZLE SHAPES OF
GAS-DYNAMIC LASERS
-
31121
EN
Journal Article
1970
01
01
Pontryagin's principle is used to study the shape of the supersonic part of the nozzle
of a carbon dioxide gas-dynamic laser whose gain is maximal. The exact shape is
obtained for the uncoupled approximation of Anderson's bimodal model. In this case,
if sharp corners are allowed, the ceiling of the supersonic part consists of a slant
rectangular sheet followed by a horizontal one; otherwise, a parabolic cylinder joins
the two sheets smoothly. Pontryagin's principle reduces the optimal control problem
to a multifactor optimal problem of the types treated by S.A. Losev, V.N. Makarov,
N.M. Reddy, and V. Shanmugasundaram
https://jsciences.ut.ac.ir/article_31121_f81585fc50858d4554b03a90f0110263.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
ON THE STATIONARY PROBABILITY DENSITY
FUNCTION OF BILINEAR TIME SERIES
MODELS: A NUMERICAL APPROACH
-
31122
EN
Journal Article
1970
01
01
In this paper, we show that the Chapman-Kolmogorov formula could be used as
a recursive formula for computing the m-step-ahead conditional density of a Markov
bilinear model. The stationary marginal probability density function of the model
may be approximated by the m-step-ahead conditional density for sufficiently large
m.
https://jsciences.ut.ac.ir/article_31122_42956bda4d838dcd36851ad72a01b18c.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
ON THE INFINITE ORDER MARKOV
PROCESSES
-
31123
EN
Journal Article
1970
01
01
The notion of infinite order Markov process is introduced and the Markov property
of the flow of information is established.
https://jsciences.ut.ac.ir/article_31123_cfcfbb8d73f48b126444e4d8a413a8ad.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
7
3
1996
09
01
OPTICAL STUDIES OF COLORED CHEMICAL
SPECIES
-
31124
EN
Journal Article
1970
01
01
Evanescent wave spectroscopy using thin optically transparent electrodes and
multiple reflections allows unique observations of the electrochemical interphase
since the region of solution sampled is typically 100 nm from the electrode in the
visible spectral region. This technique is found to be highly sensitive to the presence
of absorbing adsorbed species
https://jsciences.ut.ac.ir/article_31124_9d31fda17d859f5f1b21d32fdcbad5ae.pdf