University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
PHENETIC ANALYSIS OF THE IRANIAN SPECIES OF THE BROMUS SECTIONS GENEA, NEOBROMUS AND NEVSKIELLA
EN
A phenetic analysis of the 12 taxa or operational taxonomic units (OTUs) belonging to the three sections; Genea, Neobromus, and Nevskiella of the genus Bromus was performed. Unweighted pair-group method using arithmetic averages (UPGMA) and weighted pair-group method using arithmetic averages (WPGMA) clustering and factoriel method analyses were used to set the taxa apart. Forty-four characters including 4 vegetative and 38 reproductive characters, the chromosome number and the geographical distribution were considered in this study. The outcomes of multivariate analyses were compared with different conventional classifications. The results show that four major phenetically well-defined groups existed which confirmed the Sale's concept. This finding, however, is in odd with that expressed in Flora of U.S.S.R. The relations between the taxa were discussed, and a key to identify them was presented.
https://jsciences.ut.ac.ir/article_31747.html
https://jsciences.ut.ac.ir/article_31747_26ddb2829c1d9983f7ac0a2fb70a5c23.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
EXPRESSION OF INDUCIBLE NITRIC OXIDE SYNTHASE GENE (iNOS) STIMULATED BY HYDROGEN PEROXIDE IN HUMAN ENDOTHELIAL CELLS
EN
Inducible nitric oxide synthase (iNOS) gene expresses a calcium calmudolin-independent enzyme which can catalyse NO production from L-arginine. The induction of iNOS activity has been demonstrated in a wide variety of cell types under stimulation with cytokines and lipopoly saccharide (LPS). Previous studies indicated that all nitric oxide synthases (NOS) activated in human umbilical vein endothelial cells (HUVEC) were calcium dependent. In this work we indicate that endothelial cells can express iNOS mRNA under stimulation by cytokines, LPS and H2O2. We also found that iNOS mRNA expression has increased by augmentation of H2O2 concentration and its expression depends on increasing in time. Therefore we conclude that two isoforms of NOS are expressed in the HUVEC and induction of iNOS enzyme by H2O2 and NO production in endothelial cells may represent a novel cellular defence mechanism against oxidative stress and infections.
https://jsciences.ut.ac.ir/article_31748.html
https://jsciences.ut.ac.ir/article_31748_6fa6491075c0e28c24f902bf72b1fde2.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
PHENETIC STUDIES IN AVENA SPECIES AND POPULATIONS OF IRAN
EN
A multivariate statistical analysis was performed on morphological characters of sixty-one populations of Avena eriantha Dur. A. clauda Dur., A. barbata Pott ex Link., A. wiestii Steud., A. fatua L., A. sterilis ssp. ludoviciana L. and A. sativa L. Factor analysis revealed that intraspecific morphological variations are due to quantitative characters. Interspecific as well as intersectional relationships were investigated using cluster, discriminant analysis and ordination method based on principal components supporting the Baum’s classification.
https://jsciences.ut.ac.ir/article_31749.html
https://jsciences.ut.ac.ir/article_31749_51cca640fc22182b54953ef484d2dcfd.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
SYNTHESIS OF 4-(1-BENZYL-5-IMIDAZOLYL)-1,4-DIHYDROPYRIDINES
EN
The o-nitrophenyl group at position 4 of dihydropyridine of nifedipine analogues was replaced with 2-alkylthio-1-benzyl-5-imidazolyl substituent. Starting from dihydroxyacetone 2-alkythio-1-benzyl- 5-formyl imidazole (3) was first synthesized which was subsequently used in synthesizing symmetrical (5a-f) and asymmetrical (6a,b) dihydropyridines. Primarily pharmacological studies of the title compounds have shown they have good calcium channel antagonist activities.
https://jsciences.ut.ac.ir/article_31750.html
https://jsciences.ut.ac.ir/article_31750_1c91d92190a2ff81978d204c94b09b29.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
A NEW ALKALOID FROM FLOWERS OF ERYTHRINA STRICTA
EN
The alkaloids present in the flowers of Erythrina stricta have been isolated and characterized by spectroscopic methods. A new alkaloid 11-acetyl erysotrine has been isolated and its structure established by spectral studies (UV, IR, 1H NMR and HRMS).
https://jsciences.ut.ac.ir/article_31751.html
https://jsciences.ut.ac.ir/article_31751_db764c76ad7e49ae4976ebe657c38c04.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
SYNTHESIS OF AMINO DERIVATIVE OF INDENE AND FLUORENE FROM IMIMIUM SALT GENERATED IN ETHEREAL LITHIUM PERCHLORATE SOLUTION
EN
A series of amino derivative of 1-indene and 9-fluorene have been synthesized from their corresponding iminium salt, generated in situ in the concentrated ethereal lithium perchlorate solution, and 1-indenyl or 9-fluorenyl anions. The yields of the reactions depend on the kind of anion. Addition of 1-indeny anion to the iminium salt gives the amino derivative of 1-indene, while addition of fluorenyl anion to the iminium salt gives 9-methylenefluorene derivatives as the major product.
https://jsciences.ut.ac.ir/article_31752.html
https://jsciences.ut.ac.ir/article_31752_3bf84520d1326fdab37884c7c66fbfa5.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
THE CAUSE OF BIOMASS EXTINCTION AT THE FRASNIAN-FAMENNIAN BOUNDARY,
THE KERMAN PROVINCE
SOUTHEASTERN, CENTRAL IRAN
EN
About 35 samples were collected from lower and upper parts of the proposed Frasnianamennian boundary in three sections of Upper Devonian marine sediments of the Kerman province. The biostratigraphical and geochemical studies indicate that about 45% extinction of brachiopods probably caused by the Frasnian-Famennian bioevents, which is slightly higher than thr rate of Devonian-Carboniferous extinction elsewhere. The results of isotopic carbon and oxygen isotope analysis (? 13C%0 VPDB and ? 10O %VPDB) show a sudden decrease at the proposed Frasnian-Famennian extinction boundary which is followed by positive values above this horizon. The negative excursion may indicate a biomass extinction due to either a meteorite impact or decay of organic matter. The isotopic variations are correlated with those of faunal changes and their extinctions in the area.
https://jsciences.ut.ac.ir/article_31753.html
https://jsciences.ut.ac.ir/article_31753_63928af18a122c8283d3116959711c00.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
SHEIKH-ALI COPPER DEPOSIT, A CYPRUS-TYPE VMS DEPOSIT IN SOUTHEAST IRAN
EN
https://jsciences.ut.ac.ir/article_31754.html
https://jsciences.ut.ac.ir/article_31754_febc650b98d1e09e80d49b5f408c2e9f.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
MIXED BOUNDARY VALUE PROBLEM FOR A QUARTER-PLANE WITH A ROBIN CONDITION
EN
We consider a mixed boundary value problem for a quarter-plane with a Robin condition on one edge. We have developed two procedures, one based on the advanced theory of dual integral equations and the other, in our opinion simpler technique, relying on conformal mapping. Both of the procedures are of interest, because the former may be easier to adapt to other boundary value problems.
https://jsciences.ut.ac.ir/article_31755.html
https://jsciences.ut.ac.ir/article_31755_2540fb47b89200cf3a35074a568e1f17.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
UNIQUENESS OF SOLUTION FOR A CLASS OF STEFAN PROBLEMS
EN
This paper deals with a theoretical mathematical analysis of one-dimensional solidification problem, in which kinetic undercooling is incorporated into the This temperature condition at the interface. A model problem with nonlinear kinetic law is considered. We prove a local result intimate for the uniqueness of solution of the corresponding free boundary problem.
https://jsciences.ut.ac.ir/article_31756.html
https://jsciences.ut.ac.ir/article_31756_5f8c103650bd0f003f9b7a8ef57ec23d.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
13
1
2002
03
01
MEASUREMENT OF D2O IN WATER USING 2H(?,n)1H REACTION
EN
Utilization of Photodisintegration reaction of Deuterium, 2H(?,n)1H, is a precise technique for determining the percentage of 2H in tritiated and natural water. The 23Na(n,?)24Na reaction is a suitable ?-source for producing the 2H(?,n)1H reaction. Tehran Research Reactor was used as a neutron source for producing 24Na isotopes. The BF3 detectors were used to detect the neutron emission of H2 content of water. We obtained a linear calibration plot by repeating the experiment with many samples of different concentrations of tritiated water. With this simple portable apparatus which have been used for this purpose for the first time, and corresponding linear plot, we can monitor and determine easily and accurately the 2H concentration of an unknown sample.
https://jsciences.ut.ac.ir/article_31757.html
https://jsciences.ut.ac.ir/article_31757_b566dfa8673ade0b2c6b781d67bff4b5.pdf