Journal of Sciences, Islamic Republic of Iran
Volume:23 Issue: 4, Autumn 2012

Pectinases have multiple nature and various forms which are necessary for the hydrolysis of pectin in several conventional industrial and natural processes. In this investigation fourteen fungal strains which isolated from agricultural soils, were screened for pectinase activity. Pectinase activity were measured in vitro by assaying released reducing sugar from pectin as sole carbon source. Aspergillus foetidus and Aspergillus aculeatus showed highest pectinase activity. Rhizoctonia solani (AG-4) and Trichoderma reesei S578 showed the highest level of protein production. Reducing sugars concentration were different between 13th and 15th then reduced to 29th days after inoculation. Secreted proteins increased to 11th and 13th then decreased to 29th days. Optimum pH and temprature for pectinase activity were 5 and 50°C respectively. Glucose was detected as a degradation product by thin layer chromatography (TLC). Electrophoresis of the extracellular proteins of A. foetidus and A. aculeatus revealed two major proteins having a molecular mass of 79 and 63 kDa respectively.

V2O5/SiO2 nanoparticles was prepared via an one-pot sol gel method from vanadyl- acetylacetonate and tetraethylorthosilicate in refluxing MeOH, followed by calcination at 700 °C for 2 hours. The resultant nanoparticles was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), TGA and FTIR techniques. Rapid and efficient aromatization of 1,4-dihydropyridines (DHPs) catalyzed by V2O5/SiO2 nanoparticles is described in this presentation.

The Miocene pyroxene andesite lava flows are exposed in southeastern edge of Urumieh Dokhtar Magmatic assemblage in Iran. The hypocrystalline andesite in parts contain conspicuous co-magmatic igneous enclaves which are dark grey and occur mostly as spherical and occasionally as ribbon shapes with some showing chilled margins. Petrographic study shows that the ribbon type enclaves have been formed by merging of rounded blobs. Mineralogically the enclaves consist of plagioclase, clinopyroxene, orthopyroxene and magnetite as phenocrysts and microphenocrysts in a glassy microlitic groundmass of the same minerals. The host andesite contains the same mineral assemblage, but with high amount of glassy groundmass. The plagioclase shows a relatively large range of anorthite content (An43-91), whereas pyroxenes generally show a uniform chemical composition and are classified mainly as hypersthene (En59.67 to En73.30) and augite (Wo40.88-46.00, Fs11.08-17.07, En36.69-47.85). Enclaves are cogenetic with the host andesites and reveal the existence of disequlibrium crystallization in the magma chamber. The enclaves are resulted from a magmatic emulsion with suspended droplets of one magma in another. The rounded enclaves are likely to represent quenched blebs of intruding new andesite magma with higher liquidus that have been incorporated into the host andesitic magma in a liquid or near liquid state. Their small sizes reflect a small viscosity contrast and some turbulence during mixing. The intrusion of fresh magma also resulted convection in the magma chamber which along with the temperature differences has permitted buoyant uprising of enclaves and incorporating some of the phenocrysts from the host andesitic magma.

As a tool for exploration of concealed coal seams by modern techniques, determination of the depth of erosion of coal seams with reference to the surface of angular unconformity underlying the remnants of a key bed is conducted for the first time in coal mines of Kerman region. The angular unconformity surface (the initial surface exposure of coal seams) separates the coal seams of Jurassic age from thick limestone beds of Cretaceous age (key bed) in the coal synclinorium of Kerman region. Frequent tectonic deformation in Cenozoic led to the exhumation of portions of Cretaceous limestone (key bed) together with the coal seams of Jurassic age. The initial surface exposure of coal seams which is referred to as the "initial surface" herein, determines the upper limit of the coal seams in Early Cretaceous and is used as a "reference surface". After importing and processing the available information, namely, satellite data, field survey data, geological maps, topographic and hypsometric data, Global Positioning System (GPS) data and geo-structural data of the reference surface and present surface exposure of coal seams into GIS software, the depth of erosion of coal seams between the "initial surface" (reference surface) before erosion and the "present surface" after erosion was calculated. It is concluded that the depth of erosion of coal seams in northern region is higher than the southern region. Therefore, the remnant of the coal seams (concealed coal seams) along the dip direction is higher in the south as compared to the northern sector.

This article focuses on the estimation of population proportion when the study variable is sensitive in nature. Two implicit randomized response techniques are proposed where the unrelated trait can be chosen subjectively. In addition to unbiased estimation of population proportion and variance, an empirical study is conducted to inspect the relative efficiency facet of the proposed techniques. The cases of positive binomial and negative binomial sampling are also studied. The proposed techniques are exposed to be better at the job than the accustomed randomized response dealings in binomial sampling. Further, it is established that negative binomial sampling may result in more precise estimation of population proportion using the proposed techniques.

An analytical treatment of the electron screening effect within an active-electron model is given for positronium formation from helium atoms. A first-order distorted wave approximation with correct boundary conditions is applied to evaluate the transition amplitude. In the range of impact energy for which the introduced perturbative approach is valid, both the total and differential cross sections are calculated and the results for total cross sections are compared with the other calculations and with the available experimental data.