a. vaziri

This research aimed to investigate optimum operating condition for selective extraction of free amino acids by supercritical carbon dioxide (SFE). OVAT experiment design technique is used, setting temperature and pressure as variables and setting time at 60 minute as constant. Results show that SFE has good efficiency in extraction of alanine, glycine, serine, glutamic acid and histidine while showing unsatisfactory results on others under the chosen operating conditions for this study. Experimental extraction results are plots in excel software which shows maximum selectivity and yield for glutamic acids at (P=14 Mpa T=20 °C) and for glycine at (P=16 Mpa T=60 °C) and for alanine, serine and histidine at (P=20 Mpa T=60 °C). The highest extraction yield (3.5%) was achieved at conditions where glutamic acid, the most abundant amino acid in the sample, had the highest exaction yield.

High concentrations of heavy metals in the soil are considered as a serious risk to human health and the environment. The aim of this study was to investigate the risk of heavy metals (Pb, Ni, Zn, Cu, Cd, Cr, As, V and Co) in surface soils of Khuzestan province (2018).

This research is an experimental-applied study. For this purpose, 87 samples of surface soils were collected from Khuzestan province and analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The level of heavy metals (Pb, Ni, Zn, Cu, Cd, Cr, As, V and Co) pollution was estimated based on environmental indicators. Also, the spatial pattern of metal concentrations in surface soils was prepared in GIS (10.2).

The average concentration of heavy metals of As, Cd, Co, Cr, Cu, Ni, Pb, V and Zn was 3.22, 0.31, 9.46, 42.67, 23.92, 66.34, 9.09, 35.56 and 46.66 (mg/kg) respectively. The average concentrations of all heavy metals other than cobalt were higher than the baseline value (concentration in the earthchr('39')s crust). Based on the average value of the enrichment factor (EF), the heavy metals of Co, Cd and Zn have a high contamination. According to the comprehensive evaluation of Nemrow integrated pollution index (NIPI), 40.98% of the samples were in medium pollution and 19.54% of the samples had high pollution.

The results of environmental indicators showed that the source of pollution of studied metals was anthropogenic such as traffic, burning fossil fuels, and uncontrolled use of fertilizers, urban wastewater entering the soil, the presence of oil industries in the region and the presence of gases released from the metal industry like the steel industry in the study area.

The proper consumption of plant wastes could not only provide a possible source of natural products, but it also is an environmental friendly research. The aim of this study was to use grape wastes as a source of peroxidase.  In practice, one isoenzyme of peroxidase (POD1) was partially purified from Vitis vinifera wastes, the plant which is widely harvested in Iran. The activity of this novel peroxidase was determined using guaiacol as its substrate. The new peroxidase was partially purified and its kinetic parameters determined. The values of Km and Vmax of peroxidase for guaiacol were 83.2 mM and 0.35 M/min respectively. Optimum pH and temperature were determined for guaiacol to be 6.2 and 60°C respectively. According to SDS-PAGE results, the molecular weight of isozymes was 38-40 KD. The results indicate that agricultural leftovers from Vitis vinifera are a considerable source for a peroxidase with reliable kinetic behaviors.

Usingof nanoparticles in Composite solidpropellant formulations has extended in recent years. Nano additiveshave characteristics as high potential of reactivity, high catalytic activity and high surface area to volume ratio. For this reasons, usingof this additives in Composite solidpropellant formulations increases burning rate ofthemand consequently improvestheirperformance.on the other hand,poor dispersibility ofnanoparticles leads to agglomeration in the binder and thus reduces their effectiveness.To reduce agglomeration and thus, achievingtogood dispersibility of nanoparticles in the binder,drymixing methodisineffective and methods such as premixing, metallic nanooxidesupport,sonication,predispersingand in-situ nano-assembly areeffective.