SALICYLIC ACID INHIBITION OF
GERMINATION, ETHYLENE PRODUCTION AND
RESPIRATION IN COCKLEBUR SEEDS
text
article
1999
eng
Salicylic acid (SA) inhibited germination of cocklebur (Xanthium pennsylvanicum
Wlr), lower seeds, which are completely after-ripened and nondormant. SA also
inhibited ethylene production during a pre-germination period of the seeds. Exogenous ethylene overcame the inhibtion of the seed germination by SA. Moreover, SA reduced respiration in pre-germinating whole seeds as well as excised axial tissues.S A was suggested to inhibit more severely cyanide-sensitive respiration than cyanideresistant respiration. The inhibition of both ethylene production and respiration by S A was thought to be the cause of prevention of cocklebur seed germination . The mechanism of the action of SA is discussed in the inhibition of cockelbur seed germination
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31428_eb35e11da2575e195b46a098946c9e5d.pdf
STREPTOMYCES FRADIAE, A POTENT
PRODUCER OF CHOLESTEROL OXIDASE
text
article
1999
eng
Thirteen species of Streptomycetes, Arthrobacters and Mycobacterium were
studied for the determination of a potential cholesterol oxidase producer. Only
Streptomyces fradiae and Streptomyces rishiriences were found to be capable of
producing this enzyme. Streptomyces fradiae was selected for the production of
cholesterol oxidase and cultured in different media to find optimum media and
conditions for enzyme production. The optimum media was found (g/Lit): glucose, 12;
starch, 9; yeast extract, 6 ;peptone, 4; (NH ) SO ,7.5; Tween 80,0.5 with cholesterol,
2 as an enzyme inducer. 3 4 ?C w as the optlmum temperature for the production of
cholesterol oxidase
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31429_8484b38bde1293d7d67e7f476743d4ad.pdf
SPECTROPHOTOMETRIC- STUDY OF
THERMODYNAMICS OF SOME HEAVY
METAL COMPLEXES OF 4-(2 - PYRIDYLAZO)
RESORCINOL IN BINARY ACETONITRILEDIMETHYLFORMAMIDE
MIXTURES
text
article
1999
eng
The complexation reactions between 4-(2-pyridy1azo)-resorcinol and Cd ,H g and Pb io ns have been investigated in acetonitrile-dimethyEomamide mixtures at various temperatures using a spectrophotometric technique. The stoichiometry and
the formation constants of the complexes formed in solution were calculated by
computer refinement of absorbance-mole ratio data using nonlinear least-square
program. The stoichiometries of resulting complexes are 1 : 1,l: 1 -2: 1 and 1 :2 (metalto - ligand ratio) for Pb H, g a nd Cd r espectively. Linear relationship is observed between equilibrium constants and the mole fraction of aceionitrile in the solvent mixtures. The ?H? and AS? of complex formation reactions were calculated from the temperature dependence of the stability constants. The effects of solvent composition on stability and thermodynamic parameters were discussed
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31430_02336c04162394f8e8f0518f60d7058d.pdf
A CONVENIENT AND GENERAL SYNTHESIS OF
THIADIAZOLO [2,3-C] [1,2,4] TRIAZINES
text
article
1999
eng
Condensation and cyclization of 5-hydroxy- 1,2,4- thiadiazol-2-yl hydrazine 1
with pyruvic acid, phenacyl bromide, propargyl bromide and ally1 bromide afforded
compounds 2,5,7 3, 4 ,6 and 8 respectively, Reaction of 1 with epichforohydrine
afforded 4-hydroxy-N-[5-hydroxy- 1 ,3,4-thiadiazoly1] pyrazolidine 9
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31431_e4f962fd1fbaa9c5860e3fa795bc1936.pdf
SYNTHESIS OF NORBORNENE FURYL ESTERS
AND THEIR ENZYMATIC KINETIC
RESOLUTION BY PIG LIVER ESTRASE (PLE)
text
article
1999
eng
The reaction of furylacrylic acid with cyclopentadiene in toluene gave the
expected Diels-Alder endo-and exo-adductsin -1 : 1 ratio. The adducts were separated
by iodolactonization method to provide 3-endo-(2'-furyl) bicyclo 12.2.11 hept-5-ene-
2-exo-carboxylic acid and 3-exo-(2'-fury1)bicyclo 12.2.11 hept-5-ene-2-endocarboxylic
acid. Esterification of these acids by MeI / HMPA gave the expected
methyl esters. Kinetic resolution of racemic endo- and exo-ester adducts by
PLE(phosphate buffer, pH, 8) provided the related optically active isomers
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31432_18f26ff37fcce3eceb53fca8faa24757.pdf
TRACE ELEMENT STUDY ON THE MIXED
CARBONATE-PYROCLASTIC SEDIMENTS
(LOWER MIOCENE, CENTRAL BASIN, IRAN)
text
article
1999
eng
Geochemical investigations have permitted the refinement of the environmental
interpretation of the f-Member of the Qum formation, Central Basin, Iran, which has
been established through detailed microfacies (MF) analysis. The analysis revealed
that the f-Member carbonates consist of eight distinct microfacies designated by the
letters A through H. On the basis of petrographic characteristics and environmental
significance, the studied MF have been interpreted in terms of depositional
environments as follows: MF-A (basin); MF-B (lower slope); MF-C (reef flank); MFD
(proximal talus), MF-E (organic reef); MF-F (lagoon); MF-G (restricted marine
shoal), MF-H (restricted shelf). The concentrations of Ti, V, Fe, Co, Ni, Cu, Sr, Zr,
U and Rb have been measured in limestones from outcrop samples of this formation.
The analysis revealed a wide range of concentration both within and between
different microfacies. A volcanic eruption in the nearby area located in the northeastern
part of the sedimentary basin exerted an influence on trace element composition by
supplying pyroclastic materials to carbonate sediments. In general, the basin
microfacies is characterized by having the highest concentrations of Ti and Zr. The
lower slope microfacies has the highest values of V, Fe, Ni, Cu, Sr, U and ratios of
Ni /Co, Cu/Co and Ni/V, whereas the reef flank microfacies have only elevated
concentrations of Co. All of these traces and elemental ratios are depressed in both
proximal talus and reef rnicrofacies. The restricted marine shoal microfacies possesses
elevated Rb values and the restricted shelf microfacies is characterized by a high
concentration of Sr and elevated Cu , U and Rb values and show a slight increase in
the Ti. Fe, V, Co, Ni, Zr values.
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31433_9740c31b0848ca8831fa1d826236973f.pdf
A RESEARCH NOTE ON THE SECOND ORDER
DIFFERENTIAL EQUATION
text
article
1999
eng
Let U(t, ) be solution of the Dirichlet problem
y''+( t-q(t))y= 0 - 1 t l
y(-l)= 0 = y(x),
with variabIe t on (-1, x), for fixed x, which satisfies the initial condition
U(-1, )=0 , (-1, )=1.
In this paper, the asymptotic representation of the corresponding eigenfunctions
of the eigen values has been investigated . Furthermore, the leading term of the
asymptotic formula for - (x, (x)), (x) and is obtained where (x) is a negative eigenvalue of the Dirichlet problem on [-1, x] with fixed x < 0.
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31434_5ea31294f7373e2dccbeebc62955df5e.pdf
ON COMMUTATIVE GELFAND RINGS
text
article
1999
eng
A ring is called a Gelfand ring (pm ring ) if each prime ideal is contained in a unique
maximal ideal. For a Gelfand ring R with Jacobson radical zero, we show that the
following are equivalent: (1) R is Artinian; (2) R is Noetherian; (3) R has a finite
Goldie dimension; (4) Every maximal ideal is generated by an idempotent; (5) Max
(R) is finite. We also give the following resu1ts:an ideal of R is uniform, if and only
if, it is a minimal ideal; Ass (R) is exactly the set of all maximal ideals which are
generated by an idempotent element of R
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31435_ca1164ba1b71c3ad1a40b0d101498d3a.pdf
ON MULTIPHASE ALGORITHM FOR SINGLE
VARIABLE EQUATION USING NEWTON'S
CORRECTION METHOD
text
article
1999
eng
This paper brings to light a method based on Multiphase algorithm for single
variable equation using Newton's correction. Newton's method is derived through the
logarithmic differentiation of polynomial equation. A correction term which enhances
the high speed of convergence is hereby introduced. A translation of Newton's method
to Total Step and Single Step Methods (T. S. M and S. S. M) respectively, forms the
peak of discussion. Our method, so derived, is also discussed in the light of numerical
evidence
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31436_588346005778d2c13928a070384a0e25.pdf
A MODEL STUDY OF LASER ISOTOPE
SEPARATION BY PHOTOIONIZATION OR
PHOTODISSOCIATION PROCESS
text
article
1999
eng
In this study, the selective photoexication of isotopic mixtures by laser light is
investigated. Atomic and molecular methods are examined and rate equations are
derived for both cases. Two and three step photoionization techniques are considered
and rate equations are solved for ion yields. The molecular photodissociation process
is also studied and the dependence of the dissociation product on the laser fluence is
reported. The results of the developed model for SF molecule is compared with the
other results and the agreement found in this comparison indicates the validity of the
developed model
Journal of Sciences, Islamic Republic of Iran
University of Tehran
1016-1104
10
v.
3
no.
1999
https://jsciences.ut.ac.ir/article_31437_071aa4f461a5d56af330a81dc850958a.pdf