University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 PROBING THE ACTIVE SITE OF RHODANESE WITH DISULFIDE REAGENTS - 31210 EN Journal Article https://jsciences.ut.ac.ir/article_31210_0b5130310a93e632cdfcf01eefd6b01e.pdf

University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 LIFE HISTORY, BEHAVIOR AND MORPHOLOGY OF THE IMMATURE STAGES OF ENOCHRUS QUADRIPUNCTATUS HERBST IN THE LABORATORY (COLEOPTERA: HYDROPHILIDAE) I- LIFE HISTORY AND BEHAVIOR - 31211 EN Journal Article The life history of Enochrus quadripunctatus Herbst was studied in the laboratory. The duration of each developmental stage, larval behavior, and preimaginal mortality rate were determined. It takes the insect a total of 43 days from hatching to reach the adult stage, with a high mortality rate in the first stadium. The mortality rate decreases as the beetle passes through the immature stages. Although the species is basically similar to the other hydrophilids studied thus far, some differences with those reared in the laboratory, such as time of each developmental stage, larval behavior, and mortality rate have been observed. https://jsciences.ut.ac.ir/article_31211_fedc79bd71deb70ba0564157e3314fec.pdf

University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 PARTIAL PURIFICATION AND CHARACTERIZATION OF B-GALACTOSIDASE FROM ASPERGILLUS NIGER UV-5 - 31212 EN Journal Article The enzyme pgalactosidase from a mutant strain of A. niger UV-5 was partially purified using ammonium sulfate and acetone. The saturation range of 60-80% ammonium sulfate was found to yield 60.5% enzyme recovery with 2.4 fold purification. Acetone precipitation at enzyme: acetone ratio of 1 : 1.5 brought about a higher yield i.e. 68% and three-fold purification. The combined procedures of 1.5 volume solvent fractionation followed by 50% ammonium sulfate precipitation brought about 8-fold purification with 40% enzyme yield. The optimum temperature of the enzyme was 65°C and the optimum pH was 4- 5. The pgalactosidase was strongly inhibited by galactose. Comparative study of partially purified P-galactosidase in the present study with a commercial lactase from A. oryzae revealed comparable results https://jsciences.ut.ac.ir/article_31212_957c16082dfc126c427faaf49ea8c4c6.pdf

University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 SYNTHESIS OF 8-HYDROXY-6-METHOXY- 3-UNDECYLISOCOUMARIN AND 2-HY DROXY - 4-METHOXY-6-(2-OXOTRIDECYL) BENZOIC ACID - 31213 EN Journal Article Straightforward conversion of (+)-6,8-dimethoxy-3,4-dihydro-3- undecylisocoumarin (3) to the title isocoumarin was carried out. Hydrolytic ring opening of (3) afforded the hydroxy acid (4) which was immediately oxidized to keto acid (5) using chromic acid, Cyclodehydration of (5) afforded the 6,8- dimethoxy-3-undecylisocoumarin (6) which on selective demethylation of 8- methoxy group furnished the title isocoumarin (2). The title keto acid (1, R=H) which was obtained by hydrolytic ring opening of title isocoumarin (2) was esterified to keto ester (1, R=Me) https://jsciences.ut.ac.ir/article_31213_5ae6fe0b2972337b942e469a2e1d5678.pdf

University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 NITROIMIDAZOLES XI [I]. SYNTHESES OF DISUBSTITUTED NITROIMIDAZOLYLQUINOLINES - 31214 EN Journal Article Reaction of substituted-aniline (8) with ethyl (l-methyl-5-nitroimidazole-2- carbonyl) acetate (9) gave 4-hydroxy-2-(l-methyl-5-nitro-2-imidazolyl)- substituted-quinolines (lo), which were converted to compound 11 with phosphorus oxychloride. Substituted-2-(l-methyl-5-nitro-2-imidazo1yl)-4.- methyl-(or phenyl-) quinolines (14) were prepared through the reaction of 2- acetyl-5-nitro-1-methyl-imidazole (13) with 0-aminoacetophenones (or Oaminobenzophenones) in acid medium https://jsciences.ut.ac.ir/article_31214_d28b6717d8f0015f84b874f9d6688ef7.pdf

University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 ON THE VISCOSITY OF NATURAL GAS - 31215 EN Journal Article The existing measuremenJs of the viscosity of gaseous systems can be extended if use is made of statistical mechanics. In this work, we confine ourselves to the measurements of the viscosity of multicomponent mixtures of low-density gases. The method is applied to one sample of natural gas. https://jsciences.ut.ac.ir/article_31215_d1c790abf37bba7049eb9e8c1e520334.pdf

University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 KINETICS AND MECHANISM OF AERIAL OXIDATION OF HYDROQUINONE IN A DEVELOPER SOLUTION AND DETERMINATION OF DEVELOPER'S HALF-LIFE AT 20°C - 31216 EN Journal Article The aerial oxidation of hydroquinone in a freshly prepared developer solution at 20°C has been studied through the measurement of concentration changes by a spectrophotometric method. The concentration of consumed hydroquinone is directly proportional to time, and the equation tIl2 = C, / 0.0786 was obtained to calculate the half-life of the developer. In this equation, the half-life is in hours and the initial concentration of hydroquinone, C,, is in g/l. The following mechanism for the reaction has also been proposed https://jsciences.ut.ac.ir/article_31216_c17d923ee20f8a125139fe2dc0054ff1.pdf

University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 AN ACCURATE SOLUTION FOR THE TWODIMENSIONAL MODEL OF ALBITE USING STATISTICAL MECHANICS - 31217 EN Journal Article A two-dimensional model of Al, Si ordering in alkali feldspar is formulated and used to calcul~tea ccurately the configurational entropy for the model. For this purpose, a new method called Independent Basic Unit or IBU is introduced. To compare the results with the exact values, this method is applied to the onedimensional model of albite. The results given by IBU are found to be accurate to the extent that the deviation in free energy is less than 0.8%. The reduced configurational entropy is calculated to 'be 1.065 corresponding to 8.854 J K-1 mol-1 for the two-dimensional model. This value is within 6% of standard values obtained by using approximate calculations for the same model https://jsciences.ut.ac.ir/article_31217_1020437f3495ce43edc5a85208ee60cf.pdf

University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 A NORM INEQUALITY FOR CHEBYSHEV CENTRES - 31218 EN Journal Article In this paper, we study the Chebyshev centres of bounded subsets of normed spaces and obtain a norm inequality for relative centres. In particular, we prove that if T is a remotal subset of an inner product space H, and F is a star-shaped set at a relative Chebyshev centre c of T with respect to F, then llx - qT (x)1I2 2 Ilx-cll2 + Ilc-qT (c) 112 x E F, where qT : F + T is any choice function sending x to the point qT (x) with Ilx - qT (x)11= SUPfeT Ilx - dl (note that T is called remotal if such a choice function qT exists). We then use such an inequality to show that, under some restrictions, a uniquely remotal set is a singleton. Further, we show that if c is a centre of a remotal subset T of a norrned space E and x E E, then there exists a. functional f E E* such that I I f I1 I 1 and Ilx - qT (x)1I2 L I I c - q*(c)112 + 2 If (X - C) 12 - IIx - ~11 https://jsciences.ut.ac.ir/article_31218_b5026aa7758dc0e6f85ddb75f754ed14.pdf

University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 6 1 1995 03 01 A STUDY OF ULTRASONIC ABSORPTION OF SOME AMINO ACIDS AND THEIR MIXTURES AT PHYSIOLOGICAL pH - 31219 EN Journal Article In this paper, the ultrasonic absorption of amino acids was measured using a small cylindrical resonator at physiological pH and 25°C and a concentration of 0.1. M. The absorption of mixtures of some amino acids was also measured. In the case of cysteine-histidine, the absorption of mixtures is much larger (more than twice) than the summation of absorption of the individual amino acid. This may be due to the weak bonds between the side chain of histidine and the SH group of cysteine molecules. As for the absorption of proteins, it could also be due to weak bonds mentioned earlier https://jsciences.ut.ac.ir/article_31219_6937a522264a52ef9e2ac283812fd4db.pdf