ORIGINAL_ARTICLE
THE CALCIUM BINDING SITES OF THE
BAKERS' YEAST TRANSKETOLASE
The calcium binding sites of Bakers' Yeast Transketolase (TK) was elucidated
by estimating the pKa values of the functional groups that bind to calcium. These
pKa's were found to be 6.25 and 7.2 relating to the pKa's of the two immidazol
moieties of histidine residues on the enzyme. The rate of the binding of calcium to
the enzyme was obtained separately as a function of pH. Maximum values were
obtained at the pKa's of the immidazol rings of histidine correlating closely with the
values obtained by direct titration. The activity rate studies as a function of pH
showed that the enzyme, when bound to its cofactors, becomes further activated
over and above the regular increasing trend of the pH rate profile at similar pH's
which are optimal for calcium binding
https://jsciences.ut.ac.ir/article_31510_82d72ee698f4df1e406a40a936bda38e.pdf
1992-12-01
ORIGINAL_ARTICLE
EFFECTS OF WOOD ON THE GROWTH OF
LIGNICOLOUS FRESHWATER FUNGI
The addition of cottonwood and ash sapwood powder to YPSSl2 medium influenced
the mycelial growth of 13 species of freshwater lignicolous Ascomycetes and
Hyphornycetes. These species fall into three groups with respect to their responses to
the presence of leached or non-leached wood powder. Neither wood type showed
strong inhibitory effect on the mycelial growth of the species. Leaching did not affect
the response of the species to the presence of wood powder
https://jsciences.ut.ac.ir/article_31511_b5b2cc6ffd2d1188f04adec5d49cfc12.pdf
1992-12-01
ORIGINAL_ARTICLE
A NEW SPECTROPHOTOMETRIC PROCEDURE
FOR THE DETERMINATION OF NICKEL (11)
USING 6-PHENYL-2,3-DIHYDRO-AS-TRIAZINE-3 –THIONE
A spectrophotometric procedure for the determination of Nickel (??) based on the
complex formation with 6-phenyl-2, 3-dihydro-as-triazine-3-thione (PDTT) was
developed. A yellow compound forms and is easily extractable by chloroform at
pH>6. The mole ratio between Nickel (??) and PDTT is 1:4. The absorbance of the
complex obeys Beer's law over the concentration range of 1-7 ug of Ni (??) per ml
chloroform. This procedure can be carried out in the presence of many cations and
anions without appreciable interference.
https://jsciences.ut.ac.ir/article_31512_116a1523a6f630130e2ce2eabe3307c8.pdf
1992-12-01
ORIGINAL_ARTICLE
(II) PREPARATION AND CHARACTERIZATION
OF MN (III) COMPLEXES
We have prepared and characterized a few Mn (III) complexes by using a few
bidentate and tridentate ligands. Spectra of the manganese (Abstract
We have prepared and characterized a few Mn (III) complexes by using a few
bidentate and tridentate ligands. Spectra of the manganese (III) ion in a variety of
molecular environments are reported . On the basis of solution spectra, some of these
complexes seem to be typically distorted
https://jsciences.ut.ac.ir/article_31513_2561704edd21f995ee46666af9c156d3.pdf
1992-12-01
ORIGINAL_ARTICLE
PREPARATION AND CRYSTAL STRUCTURE OF
CaCl .[OC(NH ) ]
Calcium dichloride tetra urea was prepared by the reaction of calcium chloride
with urea in aqueous solution. The crystals are monoclinic, a= 7.633, b= 12.45 1,
c= 8.118 ?,? = 113.17, Z = 4, space group P 2,/a. The crystal structure was
determined by single crystal X-ray methods and refined to R= 0.041. The calcium
atoms are coordinated to four oxygen atoms of urea and to two chloride ions. The
coordination polyhedra are distorted octahedral
https://jsciences.ut.ac.ir/article_31514_191f247444e7bc1d4dffb80866230ea1.pdf
1992-12-01
ORIGINAL_ARTICLE
PURINE ALKYLATING AGENTS 2 ,
6-DIAMINO-8-HALO ALKYL PURINES
(POTENTIAL ANTI - MALARIALS)
Haloalkyl purines i.e. 2,6-diamino-8-(chloromethyl) purine 10; 2, 6-diamino-X-
(chloromethyl) purine 17; 2,6-diamino-8-(chloropropylp) urine 18; were synthesized
by two distinct but facile methods. The N-alkylating potential of 2, 6-diamino-8-
(chloromethyl) purine was investigated. The following products 2,6-diamino-8-(Nbenzyl-
N-methyl) purine 11; 2,6-diamino-8-(4-nitro anilinomethyl) purine 13; 2,6-
diarnino-8-(piperidino-N-methyl)Purine 14; 2,6-diamino-8-(3,4,5-trimethoxyanilinomethyl)
purine 12; of N-alkylation are reported. Antifolate activities obtained for
these compounds are also reported. 2,6-diamino-8-(3,4,5-trimethoxyanilinom ethyl)
purine demonstrated significant biological activity (ID = 1 x10 ). Most antifols
are also antimalarials e.g. trimethoprim and pyrimethamine, and therefore these 8-haloalkyl
purines may be effective antimalarials if modified by appropriate reagents
https://jsciences.ut.ac.ir/article_31515_71c5c59f6327f9454dc7644a4ab7beec.pdf
1992-12-01
ORIGINAL_ARTICLE
SYNTHESIS AND STRUCTURE ELUCIDATION
OF 1,2,4-TRIAZINO [4,3-b] 1,2,4-TRIAZINES,
1,2,4-TRIAZINO [3,4-C] 1,2,4-TRIAZINES AND
1,2,4-TRIAZINO [4,3-dl l,2,4-TRIAZINES
https://jsciences.ut.ac.ir/article_31516_ac236133d28fafb9891c24d4d4fbf410.pdf
1992-12-01
ORIGINAL_ARTICLE
B IOSTRATIGRAPHY OF SARAKHS (N.E.
IRAN) AND NAFTE- SHAHR (N.W. IRAN)
SECTIONS
It is the first time that biostratigraphic zonations of calcareous nannoplankton
from Maestrichtian to Lower Tertiary deposits of Iran are reported. The required
samples from the north-eastem and western parts of the country were selected from
the stocks of the National Iranian Oil Company. Taxonomic descriptions were not
the main objectives, although a new species and genus are apparently present in the
assemblages. The main purpose of this study is to establish the biostratigraphic
zonations and correlate them with the universally accepted standard biozones. Both
petrographic and scanning electronic microscopes were used in this investigation
https://jsciences.ut.ac.ir/article_31517_e0e870bca8e7c4d44ead707a766c6810.pdf
1992-12-01
ORIGINAL_ARTICLE
SOME GENERALIZATIONS OF WEAK
CONVERGENCE RESULTS ON MULTIPLE
CHANNEL QUEUES IN HEAVY TRAFFIC.
This paper extends certain results of Iglehart and Whitt on multiple channel
queues to the case where the inter-arrival times and service times are not necessarily
identically distributed. It is shown that the weak convergence results in this case are
exactly the same as those obtained by Iglehart and Whitt
https://jsciences.ut.ac.ir/article_31518_cddd419ccfe29371a12ee379bd287432.pdf
1992-12-01
ORIGINAL_ARTICLE
SOME RESULTS FOR SOLUTION AND FOCAL
POINTS OF NONSELFADJOINT SECOND ORDER
SYSTEMS
Consider y" (t) + A (t)y (t) + 0, y is a real n-dimensinal vector and A(t) is a real
nxn matrix, continuous on some interval. Some positivity properties of solutions
and conjugate points of y"(t) + A(t)y (t) = 0 appeared in literature. We prove similar
results for focal points
https://jsciences.ut.ac.ir/article_31519_22f1631c2610deaf30695672fbee0419.pdf
1992-12-01
ORIGINAL_ARTICLE
ON TE EXISTENCE OF PERIODIC SOLUTION
FOR CERTAIN NONLINEAR THIRD ORDER
DIFFERENTIAL EQUATIONS
https://jsciences.ut.ac.ir/article_31520_9bade70fb476f8f4cbdbe359cbbbbdaa.pdf
1992-12-01
ORIGINAL_ARTICLE
ALGEBRAIC INDEPENENCE OF CERTAIN
FORMAL POWER SERIES (II)
We shall extend the results of [5] and prove that if f = Z o a x ? Z [[X]] is
algebraic over Q (x), where a = 1, ƒ 1 and if ? , ? ,..., ? are p-adic integers, then 1 ? , ? ,..., ? are linkarly independent over Q if and only if (1+x) ,(1+x) ,…,(1+x) are algebraically independent over Q (x) if and only if f , f ,.., f are algebraically independent over Q (x)
https://jsciences.ut.ac.ir/article_31521_938ea3faeb9c21259ba15d7983c22970.pdf
1992-12-01
ORIGINAL_ARTICLE
THE LEFT REGULAR REPRESENTATION OF A
COMMUTATIVE SEPARATIVE SEMIGROUP
In this paper, a commutative semigroup will be written as a disjoint union of its
cancellative subsemigroups. Based on this fact we will define the left regular
representation of a commutative separative semigroup and show that this
representation is faithful. Finally concrete examples of commutative separative
semigroups, their decompositions and their left regular representations are given.
https://jsciences.ut.ac.ir/article_31522_62c3b934436e4f53005d63ad8ce419b0.pdf
1992-12-01
ORIGINAL_ARTICLE
NONDYNAMICAL ANALYSIS OF SPIN AMPLITUDES
IN PION-PROTON ELASTIC SCATTERING
IN OPTIMAL FORMALISM AT 6.0 GeV/C
Optimal conditions are used in nondynamical formalism to diagonalize the pionproton
reaction matrix as much as possible. Invariance laws are imposed to simplify
the relationship between observables and bilinear combination of amplitudes. Transverse
amplitudes are determined by using measured polarization parameter in xfp
elastic scattering at 6.0 GeVIC
https://jsciences.ut.ac.ir/article_31523_9c9409ef3e567bf964a4e47c71f71d10.pdf
1992-12-01