ORIGINAL_ARTICLE
Identification of p53 Gene Mutations among Iranian Patients Involved with Esophageal Squamous Cell Carcinoma: the Efficiency of the Two Different Methods
https://jsciences.ut.ac.ir/article_31619_9dcc592a108cb4157b8a9af720777d3b.pdf
2005-03-01
ORIGINAL_ARTICLE
Enzymatic-Like Properties of dsDNA and Its Comparison with ssDNA
https://jsciences.ut.ac.ir/article_31620_78df058cd1dc9631c0c4f70fd67afb0a.pdf
2005-03-01
ORIGINAL_ARTICLE
Evidence for the Essential Arginine and Histidine Residues in Catalytic Activity of Glucose 6-Phosphate Dehydrogenase from Streptomyces aureofaciens
Glucose 6-phosphate dehydrogenase (G6PD) was purified from Streptomyces aureofaciens and inactivated with butanedione and diethylpyrocarbonate. Incubation of the enzyme with butanedione resulted in a rapid activity loss (80%) within 5 min, followed by a slow phase using a molar ratio to enzyme concentration of 100. Fluorescence studies showed a conformational change in the butanedione-modified enzyme. NAD+, NADP+ and glucose 6-phosphate protected the enzyme against inactivation. Diethylpyrocarbonate (2 mM) completely inactivated the enzyme after 2 min. Stoichiometry of the inactivation showed 2 moles of histidine residues per mole of enzyme with complete activity loss. Maximum emission spectrum of the enzyme decreased (23%) upon modification and the presence of NAD+ or NADP+ further decreased the fluorescence by 27% and 10.5%, respectively. The data suggest that essential arginine and histidine residues may be involved in the catalytic activity of Streptomyces aureofaciens G6PD
https://jsciences.ut.ac.ir/article_31621_9113301d6db6f4521430630c7ae3c7ec.pdf
2005-03-01
ORIGINAL_ARTICLE
Detection of Plasmodium falciparum Directly from Blood Samples Using the Polymerase Chain Reaction
https://jsciences.ut.ac.ir/article_31622_f31e60b18858c0ac4a17ef9744428389.pdf
2005-03-01
ORIGINAL_ARTICLE
Purification of Saccharomyces cerevisiae eIF4E/eIF4G/Pab1p Complex with Capped mRNA
Protein synthesis is one of the most complex cellular processes, involving numerous translation components that interact in multiple sequential steps. The most complex stage in protein synthesis is the initiation process. The basal set of factors required for translation initiation has been determined, and biochemical, genetic, and structural studies are now beginning to reveal details of their individual functions in this process. In Saccharomyces cerevisiae, eIF4E is the central component of the eIF4F complex, which binds the 5? cap structure of the mRNA. This complex is significant in many ways. First of all, it is essential for translational initiation, mediating the initial interactions of ribosomes with the mRNA 5? end. Secondly, because of its key role in interacting with the 5? end of the mRNA, and possibly also with proteins such as the poly (A) binding protein (PABP) at the 3? end of the mRNA, the eIF4F complex is thought to be involved in the process of mRNA degradation. Thirdly, eIF4F is a site of translational regulation, responding to signals communicated along the signal transduction pathway that are induced by stress conditions or hormones. To study about the interactions of eIF4E within the eIF4F complex, we tried to find conditions that would enable us to obtain structural data about S. cerevisiae eIF4E/eIF4G/Pab1p interactions. To yield information about the eIF4E/eIF4G/Pab1p complex, affinity chromatography was conducted using synthetic biotinylated capped mRNAs. For this purpose, a capped 55-nucleotide RNA was synthesised and labeled with Biotin-21-UTP at the 3?-end in an in vitro transcription reaction. For Biotin labeling of mRNA, rUTP was substituted with Biotin-21-UTP in the reaction. Soft Link Avidin Resin was used for the isolation of biotinylated mRNA, which can bind eIF4E via the capped structure at the 5?-end of the mRNA and Pab1p via the poly (A) tail at 3? end. These results confirm that a highly pure eIF4E/eIF4G/Pab1p/RNA complex can be generated using the procedures outlined.
https://jsciences.ut.ac.ir/article_31623_39d6364742c1e7b8fa9cca00f9f3ca02.pdf
2005-03-01
ORIGINAL_ARTICLE
Synthesis of some New Thiosemicarbazide and 1,3,4-Thiadiazole Heterocycles Bearing Benzo[b]Thiophene Nucleus as a Potent Antitubercular and Antimicrobial Agents
Reaction of 2-hydrazinocarbonyl-3-chloro-5-phenoxy-benzo[b] thiophene with different substituted phenyl isothiocyanate gave N-substituted arylthiosemi-carbazide derivatives (1a-h). 1,3,4-Thiadiazole derivatives (2a-h) were prepared by the cyclization of arylthiosemicarbazides (1a-h) with concentrated sulphuric acid. All the compounds were screened for their antitubercular activity against Mycobacterium tuberculosis (H37Rv) and antimicrobial activity against various microorganisms
https://jsciences.ut.ac.ir/article_31624_0196f34b7e1c5995b59bc6f9d406a688.pdf
2005-03-01
ORIGINAL_ARTICLE
-Solid Lithium Perchlorate, a Highly Efficient and Chemoselective Catalyst for the Acetalyzation of Aldehydes
-A simple, efficient, and general method has been developed for the chemoselective acetalization of aldehydes with 1,3-propanediol, 1,2-ethanediol and trimethyl orthoformate in the presence of solid lithium perchlorate under solvent-free conditions. Both cyclic and acyclic acetals of aldehydes were obtained under environmentally benign conditions in good to excellent yields.
https://jsciences.ut.ac.ir/article_31625_b809e4da9298d29895a6c2684b62d555.pdf
2005-03-01
ORIGINAL_ARTICLE
Magmatic and Metamorphic Fluids in Pegmatite Development: Evidence from Borujerd Complex, Iran
The Borujerd complex of western Iran is composed of intrusions and their surrounding contact aureole, with, pegmatites and quartz veins. Pegmatites differ in mineralogy, origin and age, and two groups can be distinguished. The Older Pegmatites (about 120 Ma age) intruded contact metamorphic rocks from the early magmatic stage, while the Younger pegmatites (52-70 Ma age) formed during the late magmatic stage. Fluid inclusions from quartz veins, pegmatites and hornfelses have been studied using microthermometry, scanning electron microscopy, laser Raman spectroscopy and crush leach analysis to evaluate the source of fluids from which pegmatites formed. Host minerals of fluid inclusions in pegmatites are quartz and tourmaline, whereas in the hornfelses they are andalusite and quartz. Low salinity H2O inclusions are common in the Older Pegmatites and quartz veins whereas high salinity H2O inclusions occur in Younger Pegmatites. CO2-H2O fluid inclusions occur in Older Pegmatites and hornfelses, and in addition pure CO2 inclusions are observed in some hornfelses. The distribution of the different types of fluid inclusions suggests that CO2 fluids evaluated during metamorphism. The source of the carbon may be graphite which is present in hornfelses and the basement mica schists. Low salinity fluids in Older Pegmatites, quartz veins and hornfelses could have formed from low salinity late magmatic fluids. However, some mixing took place between magmatic fluids and metamorphic fluids to form CO2-H2O inclusions. High salinity magmatic fluids are only associated with Younger pegmatites and show low first ice melting temperature (?61.0 to ?75.5°C), probably due to the presence of Ca.
https://jsciences.ut.ac.ir/article_31626_c179f6a673781007009f6942dfc06f88.pdf
2005-03-01
ORIGINAL_ARTICLE
Estimating the Saturated Hydraulic Conductivity of Granular Material, Using Artificial Neural Network, Based on Grain Size Distribution Curve
https://jsciences.ut.ac.ir/article_31627_8e781946401f219c3c64411a1d6f09b2.pdf
2005-03-01
ORIGINAL_ARTICLE
Some Probability Inequalities for Quadratic Forms of Negatively Dependent Subgaussian Random Variables
In this paper, we obtain the upper exponential bounds for the tail probabilities of the quadratic forms for negatively dependent subgaussian random variables. In particular the law of iterated logarithm for quadratic forms of independent subgaussian random variables is generalized to the case of negatively dependent subgaussian random variables.
https://jsciences.ut.ac.ir/article_31628_8bee8313f2072d9dfd871257ba71f132.pdf
2005-03-01
ORIGINAL_ARTICLE
Maximal Inequalities for Associated Random Variables
In a celebrated work by Shao [13] several inequalities for negatively associated random variables were proved. In this paper we obtain some maximal inequalities for associated random variables. Also we establish a maximal inequality for demimartingales which generalizes and improves the result of Christofides [4].
https://jsciences.ut.ac.ir/article_31629_aefe8a0bdfa64c6f8ebc907c3e4af9ac.pdf
2005-03-01
ORIGINAL_ARTICLE
Hypercentral Constituent Quark Model and Isospin for the Baryon Static Properties
So far the static properties of hadrons have been introduced in various models. The static properties of hadrons (charge radius, magnetic moment, etc.) are useful for understanding the quark structure of hadron. In this work we have introduced the hypercentral constituent quark and isospin dependent potentials. Here constituent quarks interact with each other via a potential in which we have taken into account the three body force effect and standard two-body potential contributions. According to our model the static properties of hadrons containing u, d, and s quarks are better than the other models and closer to the experiment. The two key ingredients of this improvement are the effective quark-gluon hypercentral potentials, the hyperfine interaction and isospin-dependence potential.
PACS index12.39 .Ba, 12.39. Ki, 12.39. Pn,
https://jsciences.ut.ac.ir/article_31630_6d36f6a509f295b2a527bca78f6ec2df.pdf
2005-03-01