Novel methods for the synthesis of 3-arylmethyl-4-thiazolidine carboxylic acid-2-thiones and their methyl esters

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Hybrid chitosan derivative-carbon suport for oxygen reduction reactions

New hybrid chitosan derivative-carbon black was prepared and used as support for Pt nanoparticles. These catalysts improved the activity toward oxygen reduction reaction (ORR), compared with those of commercial Pt/C catalyst. The biopolymer chitosan provided an efficient and sustainable surface nitrogen source associated with the superior performance of the catalysts.Peer reviewe

Chromium removal from aqueous solution by a PEI-silica nanocomposite

It is essential and important to determine the adsorption mechanism as well as removal efficiency when using an adsorption technique to remove toxic heavy metals from wastewater. In this research, the removal efficiency and mechanism of chromium removal by a silica-based nanoparticle were investigated. A PEI-silica nanoparticle was synthesized by a one-pot technique and exhibited uniformly well-dispersed PEI polymers in silica particles. The adsorption capacity of chromium ions was determined by a batch adsorption test, with the PEI-silica nanoparticle having a value of 183.7 mg/g and monolayer sorption. Adsorption of chromium ions was affected by the solution pH and altered the nanoparticle surface chemically. First principles calculations of the adsorption energies for the relevant adsorption configurations and XPS peaks of Cr and N showed that Cr(VI), [HCrO4](-) is reduced to two species, Cr(III), CrOH2+ and Cr3+, by an amine group and that Cr(III) and Cr(VI) ions are adsorbed on different functional groups, oxidized N and NH3+

Designing and establishment of ISO/IEC 17025 in 3aboratories of Caspian Sea ecological research center

The project was carried out between March of 2007 and November of 2009.Five laboratories of research center (Clinical pathology, Plankton, Molecular genetics, Pollutants, Analysis Instrument were selected for accreditation. The main stages for establishment of the system consisted of: 1-Conducting a gap analysis to compare the present state of the laboratories with ISO/IEC 17025 Training 2 General requirements for the competence of testing and calibration laboratories Validation of methods Estimation of uncertainty Internal audits 3- Performing of technical and management requirements 4-Submit of quality manual to Iran Accreditation System (IAS) in order to accredit In January of 2010 the laboratories were accredited by Iran Accreditation System (IAS). The main results were including: 1-Increase the accuracy of measurement 2-Improvement of the Repeatability and Reproducibility of the test methods 3-Traceability and standardization of test methods 4- Calibration of measurement instruments 6- Updating of test methods 7-Standardization of physical condition of the laboratories 8- Getting the certification from Iran Accreditation System (IAS)

The Study on Electrospinning of Nanofibers from Sodium Alginate and the Effects of Different Co-solvents on Electrospinning of Polymer Solution

In the past decade, electrospinning as a facile and effective means in producing nanofibers with diameters ranging from microns down to a few nanometers has been developed and considered important. In this work, electrospinning of an interesting natural biopolymer, sodium alginate, has been investigated. The results showed that water solution of sodium alginate cannot be electrospun into nanofibers. Moreover, using different organic solvents and surfactants did not help the spinnability of the polymer solution. To improve the solubility of the polymer in organic solvents, we used ammonium alginate or alginic acid instead of sodium alginate, but the results were not satisfactory. However, we were able to electrospin the sodium alginate from aqueous solution by blending it with a synthetic polymer, poly(ethylene oxide) (PEO). The type of interactions between sodium alginate and PEO was examined by FTIR. The morphology and diameter of the electrospun fibers were observed and determined by using an optical microscope and a scanning electron microscope (SEM). The measurement of solution properties such as viscosity showed a strong dependence of spinnability and fiber morphology on solution viscosity and thus on alginate-to-PEO blend ratios