2021-08-13T05:08:45Z https://jsciences.ut.ac.ir/?_action=export&rf=summon&issue=3952

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 The activity of phospholipase C in crude enzymatic preparation of Melia azadiracht seeds (Neem seeds) was studied by the use of lecithin as a substrate in aqueous medium. The enzyme activity was found optimum at pH 2.5 and temperature 35?C. The phospholipase C was found heat labile, being inactivated 88% within 10 minutes at 90°C 1992 06 01 https://jsciences.ut.ac.ir/article_31197_4c131da55d7e8ccb024e6aa0d2ebd74a.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 The first enzyme of the pathway for uridine diphosphate N-acetyl-D-glucosamine (UDPAG) biosynthesis i.e. L-glutamine: D-fructose 6-P amidotransferase (E.C. 2.6.1.16) was purified 52-fold from human placenta using methanol fractionation and column chromatography on DEAE-Sephadex A-50. The enzyme showed optimal activity in a broad range of pH from 5.8 to 7.8 in both phosphate and cacodylate buffers. Its K m value for D-fructose 6-P was found to be 2.14 mM. The enzyme was inhibited up to 76% in the presence of 0.12mM UDPAG. A K value of 6.6 ?M was obtained for the feedback inhibition of this enzyme by UDPAG 1992 06 01 https://jsciences.ut.ac.ir/article_31198_379a5afcc4955d121319a38a7b95410b.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 The binding of sodium n-dodecyl sulphate (SDS) to Aspergillus niger catalase in various ionic strengths at pH 6.4 and a temperature of 27? and 37?C has been studied over a range of SDS concentrations using equilibrium dialysis and fluorescence spectroscopy techniques. The binding data were used and interpreted in terms of theoretical models (Scatchard Equation and Wyman Binding Potential). The cationic ionizable residues were estimated and have been compared with data from amino acid analysis 1992 06 01 https://jsciences.ut.ac.ir/article_31199_13c31d71bebeaf5d294a35348664858f.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 FABMS analysis of T-lb peptide before and after one cycle of Edman degradation indicated an unblocked N-terminal Thr residue for this tryptic peptide. In contrast , our data showed a molecular protonated ion, MH + for T- la peptide at 655 mass units (mu) which is 42 mu higher than the MH ion of T- 1b peptide. In addition, T- la peptide was not amenable to one cycle of manual Edman degradation. These observations suggest that the N-terminal residue of T- 1 a peptide is blocked by a chemical group having a mass of 42 mu. This observation is consistent with the presence of an N-terminal acetyl group. This prediction was further investigated by complete characterization of the gas phased fragment ions, originated from the individual peptides, using link-scanning approach. The fragment ions again suggest an acetyl group attached to an N-terminal threonine. In addition, the fragment ions provide evidence that the two peptides (T-la and T-lb) have identical structures except for the N-acetyl group 1992 06 01 https://jsciences.ut.ac.ir/article_31200_331f7b41e33370ddae16190f0f100677.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 Methyl tetra - 0-methyl- ?-D- glucopyranoside is stereoselectively prepared from tetramethyl-D- glucopyranose by using (MeI+NaH) in toluene (86%) or cyclohexane (85%), while its ?- isomer is best synthesized in hexamethyl phosphoramide (64%). Similarly, methyl tetra-o-methyl-?- D-mannopyranoside is synthesized in cyclohexane (80%), while its ?- isomer is predominantly prepared by (MeI+n-BuLi) in cyclohexane (98%). The ?-and ?- isomers of these glycosides were identified and quantified by G.C 1992 06 01 https://jsciences.ut.ac.ir/article_31201_d9336c74c284aaa7a8e5b78a95096779.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 3,5- dinitrobenzoyl chloride-pyridine system has been used for dehydration of aldoximes and carboxamides at room temperature 1992 06 01 https://jsciences.ut.ac.ir/article_31202_dc468d3f00aada954933c9e873c0552e.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 Spiro-4- thiazolidinones have been synthesized by the cyclocondensation of phthalazinyl hydrazones with cyclic ketones and substituted mercapto acetic acids. Compounds were screened for their antibacterial, antifungal and antihypertensive activity. The combined elemental analyses and spectroscopic data prove the authenticity of the synthesized compounds 1992 06 01 https://jsciences.ut.ac.ir/article_31203_17d2a7bd6895c4a10b4a849643cbaddd.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 A new homologous series of linear aliphatic polyesters, such as poly (cis-2- butenylene carboxylate)S, PBms (m is the number of methylene groups in the acid component, m=2-8 have been synthesized by direct polyesterification reactions in anisole, as solvent. FT-IR, 400 MHz H- NMR, C-NMR and elemental analysis were used to establish the structure of polyesters. Molecular weight distributions were studied by GPC. The most narrow distributions were found to be for PB2 and PB8, whereas, the average molecular weight for all polyesters, except PB6, was about 3000-400 1992 06 01 https://jsciences.ut.ac.ir/article_31204_21db458be308faa7ac7777f856b35723.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 The aerial parts of Salvia glutinosa afforded in addition to lupeol, a - and ? - amyrin a furanosesquiterpene, its structure being established by high field NMR techniques. The relative configuration at C-1, C-10, C-4, C-5 and C-6 of 6?tigloyloxyglechomafuran 1 was determined by the observed NOE'S 1992 06 01 https://jsciences.ut.ac.ir/article_31205_58debdab22d8cc89eba3fb892628a0d0.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 Twenty four samples of xenoliths and country rocks from the 1961 lava flow of Calbuco volcano have been studied. Fourteen samples have been analyzed for major elements and P, Ni, Ba, Cr, V, Zr, Sc, Y, and Sr. Five of these samples were further analyzed for Sm, Nd, Sr, and Pb isotope ratios. Seventeen samples were analyzed under the microscope and three samples were analyzed by microprobe for their pyroxene composition. Based on petrograghic studies xenoliths were divided into three groups. Fine grained xenoliths (groups I and II) probably formed from metamorphosed MORB-like basalts , whereas coarse grained xenoliths (group III) were apparently derived from cumulate minerals that crystallized from the Calbuco magma. The fine grained xenoliths were probably entrained in magma at intermediate levels of the crust, near the stability limit of amphibole to form pyroxene and plagioclase. In the coarse grained xenoliths amphibole that form at depth dehydrated as the xenoliths were brought to the surface. The country rocks are apparently unrelated to the xenoliths. 1992 06 01 https://jsciences.ut.ac.ir/article_31206_821a9beb1406b08df96330dd206bbdea.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 In this paper we give a 2-generator 2-relation presentation for the group SL(2,121). This proves that SL(2,121), the covering group of PSL(2,121), is efficient 1992 06 01 https://jsciences.ut.ac.ir/article_31207_351b7ee8c8eaa0952dea236adfecf806.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 Following recent works of several authors like Huilgol, Bhattacharya etd. and Javadpour et al., this paper is to contribute further to the literature of axial flow in a rotational coaxial rheometer. We consider axial flow of Herschel Bulkley mode1 between two concentric cylinders with the inner one rotating, while the outer cylinder is held stationary. An attempt has been made to direct the analysis toward an examination of the relationship between moment (M) and angular velocity ( ) at the inner cylinder. The radial dependence of the shear stress and viscosity follows directly by our mathematical analysis with a simple numerical procedure. We describe the relationship between shear stress and shear rate and the dependence of these on axial flow rate in the annular region, for power law and Herschel Bulkley fluids 1992 06 01 https://jsciences.ut.ac.ir/article_31208_71f308e87be0074149af365e1a0ceff7.pdf

1992-06-01 10.22059

Journal of Sciences, Islamic Republic of Iran J.Sci.I.R.I 1016-1104 1016-1104 1992 3 1 A heuristic way to calculate the approximate value of the Casimir force is introduced 1992 06 01 https://jsciences.ut.ac.ir/article_31209_0ac7170baac98705020c8c5195a32946.pdf