مجله علوم جمهوری اسلامی ایران
سال:1381 | دوره:14 | شماره:1 |تعداد مقالات:17

Interference between the two members of reoviridae family, which multiply inside the cytoplasm of the host cell, was investigated. Monkey kidney cells (BSC-1) were coinfected with reo and rota viruses and the amount of virus produced was determined by TCID50 and Fluorescent Focusing Assay (FFA). Upon coinfection the growth of reovirus was reduced considerably in presence of rotavirus. Electron microscope examination of viruses extracted from mixed infected cells revealed that only rotavirus particles were present. This observation was confirmed by examining thin section of coinfected cells in which only cytoplasmic rotavirus like particles were visualized. Interference between rotavirus and reovirus was not at the level of adsorption and receptor attachment competition. Analysis of viral RNA extracted from the coinfected cells revealed that RNA genomes of both viruses were synthesized but after the first passage only rotavirus RNA was present in the infected cells. Similarly viral proteins of both viruses were produced in coinfected cells as was shown by polyacrylamide gel electrophoresis, followed by immunoblotting and by the immunofluorescence staining. Since there was no inhibition of viral macromolecular synthesis in mixed infected cells it was concluded that inhibition of reovirus maturation in presence of rotavirus was probably at the level of virus assembly.

Helicobacter pylori (H. pylori) infection, which is always accompanied by inflammation, and increased expression of the cell adhesion molecule CD44 have both been purported to be correlated with gastric cancer. Specifically, altered expression of alternatively spliced CD44 transcripts has been found in many cancers, including cancer of the stomach. Considering the association between H. pylori infection and inflammation, it is possible that the correlation between CD44 alternative splicing and gastric cancer is due to inflammation. To test this, we compared the expression of all CD44 variant exons V2-V10 in non-cancerous individuals with and without inflammation. To ascertain the extent to which the effect of H. pylori is mediated by inflammation, CD44 variant exon expression in inflamed individuals with and without H. pylori infection was compared.CD44 variant exon expression was assessed in gastric biopsy samples of 43 H. pylori infected (H. pylori+) and 46 non-infected (H. pylori-) individuals using nested RT-PCR. Thirteen of the non-infected individuals were without inflammation. The results suggest that inflammation alone does not change CD44 expression. There was a significant correlation between the expression of CD44 variant exons V8, V9 and V10 and H. pylori infection. Further investigations will be necessary to address the possibility that infection and inflammation have synergistic roles in the increased expression of V8, V9 and V10. These exons code for parts of the extracellular portion of the protein and changes in their expression may affect oncogenic processes because of changed affinities for the extracellular matrix.

A one-pot synthesis of (S)-(-)-propranolol is reported. Zn(NO3)2/(+)-tartaric acid catalyzed enantioselective synthesis of (S)-(-)-propranolol via kinetic resolution of key intermediate α-naphthyl glycidyl ether with high optical and chemical yield.

Two modified methods for assaying sodium diclofenac were developed by GC  and HPLC. Diclofenac was converted into methyl ester derivative by methyl iodide in acetone. The ester was extract and subjected to GLC with flame ionization detector. %5 SE-30/chrom W-HP (80-100 mesh) was used as a column in GC. For reversed phase HPLC, the mobile phase was methanol and water (55-45). The separation was performed on an analytical 300×3.9 mm i.d. μ-bondapak phenyl column using UV detector (274 nm). O-(4-chlorobenzoyl)benzoic acid and mefenamic acid were used as internal standard for GC and HPLC method respectively. The stability of diclofenac was examined by results obtained from two chromatographic methods at high temperature. The described HPLC and GC methods were successfully applied for the prediction of the shelf life period of diclofenac.  

The porphyry copper deposit at Sungun is located in East Azarbaidjan, NW of Iran. The Sungun porphyries (Oligo-Miocene) occur as stocks and dikes and intruded a series of Oligocene pyroclastics and lavas, Eocene arenaceous-argillaceous rocks, and Upper Cretaceous carbonates. The porphyry stocks are divided into two groups, 1) porphyry stocks I (quartz monzo-diorite) and 2) porphyry stock II (quartz monzonite, granodiorite, and granite). Porphyry stock II hosts the copper and molybdenum ores. Numerous and various cross-cutting veinlets and micro-veinlets of quartz, sulfides, sericite, carbonates, and sulfates were developed in porphyry stock II. Three distinct types of hydrothermal alterations and sulfide mineralizations are recognized at Sungun; 1) hypogene, 2) contact metasomatic, and 3) supergene. The vertical variations in concentration of 12 elements (S, Cu, Mo, K, Rb, Ca, Sr, Na, Mg, Fe, Al, and Si) across various hypogene alteration zones at Sungun demonstrate that S, Cu, Mo, Fe, K, and Rb are mainly concentrated in the phyllic and potassic-phyllic zones where the abundance of Ca, Sr, Mg, and Na are appreciably low relative to the potassic zone. The values of Al and Si are relatively high in the supergene zones and their abundance gradually decrease downward toward the potassic zone. The copper and molybdenum are substantially localized in the phyllic and potassic-phyllic zones particularly in the central part of the mineralized porphyry stock where the rocks underwent severe stockwork-type fracturing and micro-fracturing. Their concentrations are relatively low in the potassic zone.

The paragenetic sequence at the Zarshuran arsenic deposit, NW Iran demonstrates that during the late stage of mineralization, gold precipitated with orpiment, realgar and arsenian pyrite. Thermodynamic calculations have been used to model sulphur and arsenic speciation and solubility at the P-T conditions of the late stage mineralization, reconstructed based on fluid inclusion studies. Arsenic was probably transported as the As+3 complex; H3AsO3 0, while the dominant Au complex was Au(HS)2 -. The calculations indicate that both pH and fO2 have opposing effects on gold and arsenic solubilities. Hence co-precipitation was not simply a response to changes in pH and fO2. Experimental data and geochemical modelling results indicate that pH, fO2, P, T and S availability are the main equilibrium factors controlling gold and arsenic transport and precipitation. The proposed geochemical model suggests that partial reduction of an oxidizing As-rich fluid of partial magmatic origin (As~S), leached gold from the Precambrian metamorphic rocks as it was reduced, but further reduction by the black shale resulted in gold and arsenic coprecipitation. An alternative model for As and Au co-precipitation is a kinetic one, with Au being adsorbed onto growing orpiment surfaces despite being undersaturated in the fluid. The result shows the condition in which an arsenic saturated fluid with mAs=mS may persist to a point where gold bisulphide has maximum solubility, and so may leach gold. Further reduction from that point may causes gold and orpiment co-precipitation. The high level As to S concentrations is one of the main features here, and is not known for the Zarshuran fluid, although data from different magmatic sources suggest that the requirements are within the range of magmatic fluids.

A two-factor experiment with interaction between factors wherein observations follow an Inverse Gaussian model is considered. Analysis of the experiment is approached via an empirical Bayes procedure. The conjugate family of prior distributions is considered. Bayes and empirical Bayes estimators are derived. Application of the procedure is illustrated on a data set, which has previously been analyzed by other authors.

Copper films (250 nm) deposited on glass substrates, at different substrate temperatures. Their optical properties were measured by ellipsometery (single wavelength of 589.3 nm) and spectrophotometery in the spectral range of 200– 2600 nm. Kramers Kronig method was used for the analysis of the reflectivity curves of Cu films to obtain the optical constants of the films, while ellipsometery measurement was carried out as an independent method. The influence of substrate temperature on the microstructure of thin metallic films [Structure Zone Model (SZM)] is well established. The Effective Medium Approximation (EMA) analysis was used to establish the relationship between the SZM and EMA predictions. Good agreements between SZM as a function of substrate temperature and the values of volume fraction of voids obtained from EMA analysis, are obtained; by increasing the substrate temperature the separation of the metallic grains decreases hence the volume fraction of voids decreases and denser films are formed. The unusual (anomalous) behavior of the void fraction as a function of wavelength for different substrate temperatures, in certain wavelength region is explained to be due to the roughness value of the film surface. This value corresponds to this wavelength region scattering from the surface roughness. This phenomenon may be used as a technique for surface roughness measurement.