Pakistan Council of Scientific and Industrial Research Labs Complex

Peshāwar, Pakistan

Pakistan Council of Scientific and Industrial Research Labs Complex

Peshāwar, Pakistan
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Shabbiri K.,The University of Lahore | Ahmad W.,The University of Lahore | Syed Q.,Pakistan Council of Scientific and Industrial Research Labs Complex | Adnan A.,The University of Lahore
Brazilian Journal of Microbiology | Year: 2010

A respiratory complex was isolated from plasma membrane of pathogenic Proteus mirabilis strain ATCC 29245. It was identified as complex II consisting of succinate:quinone oxidoreductase (EC 1.3.5.1) containing single heme b. The complex II was purified by ion-exchange chromatography and gel filtration. The molecular weight of purified complex was 116.5 kDa and it was composed of three subunits with molecular weights of 19 kDa, 29 kDa and 68.5 kDa. The complex II contained 9.5 nmoles of cytochrome b per mg protein. Heme staining indicated that the 19 kDa subunit was cytochrome b. Its reduced form showed absorptions peaks at 557.0, 524.8 and 424.4 nm. The a-band was shifted from 557.0 nm to 556.8 nm in pyridine ferrohemochrome spectrum. The succinate: quinone oxidoreductase activity was found to be high in this microorganism.


Khan U.S.,University of Peshawar | Khattak N.S.,Sarhad University of Science and Information Technology | Rahman A.,Pakistan Council of Scientific and Industrial Research Labs Complex | Khan F.,Pakistan Council of Scientific and Industrial Research Labs Complex
Journal of the Chemical Society of Pakistan | Year: 2011

This paper deals with the synthesis and characterization of magnetite nanoparticles via the controlled modified chemical coprecipitation method using ferrous and ferric salt solution in alkaline medium with out any surfactant addition. The nanoparticles of 9-14 nm in size were prepared under non-oxidized environment and characterized by transmission electron microscopy, energy dispersive X-rays spectrometry, X-ray diffraction and BET surface area analyzer. The reaction temperature and the stirring rate during the precipitation were found to be crucial in limiting their size and size distribution. Low temperature and high stirring rate are the appropriate conditions for the synthesis of these particles.


Khan U.S.,Sudan University of Science and Technology | Khattak N.S.,Sarhad University of Science and Information Technology | Manan A.,Sudan University of Science and Technology | Rahman A.,Pakistan Council of Scientific and Industrial Research Labs Complex | And 2 more authors.
Journal of Electronic Materials | Year: 2014

Temperature, stirring rate, stirring time, reaction pH, and concentration of precursors during synthesis were found to be crucial in determining the size of the magnetite nanoparticles (NPs) obtained. The relationship between synthetic conditions and the crystal structure, particle size, and size distribution of the NPs was studied. Surface coating of iron oxide NPs was performed in two steps. Magnetite NPs were prepared by coprecipitation then coated with silica by use of a sol–gel process. Saturation magnetization of the magnetite NPs increased from 47.23 to 49.12 emu/g when their size was increased from 8.89 to 9.39 nm. Magnetite NPs in the size range 11–12 nm, coated with silica, are monodispersed and their corresponding saturation magnetization is 40.67 emu/g (11 nm) and 34.65 emu/g (12 nm). The decrease in the saturation magnetization of the coated samples is attributed to the increase in the amount of tetraethyl orthosilicate. © 2014, The Minerals, Metals & Materials Society.


Khan U.S.,University of Peshawar | Khattak N.S.,University of Peshawar | Rahman A.,Pakistan Council of Scientific and Industrial Research Labs Complex | Khan F.,Pakistan Council of Scientific and Industrial Research Labs Complex
Journal of the Chemical Society of Pakistan | Year: 2011

Top down and bottom up are two fundamental routes for the formation of magnetite nanoparticles (MNPs). These routes are generally utilized for producing technologically and economically significant MNPs. This review discusses the synthesis of MNPs and outlines methods of preparation that allow control over the size, morphology, surface treatment and magnetic properties of the nanoparticles. In the past, long grinding of bulk magnetite in the presence of stabilizing surfactants produced the first accepted ferrofluid containing MNPs. Such mechanogrinding methods were inherently time consuming and costly. Currently, perhaps the most commonly accepted approaches for creating MNPs concentrate around different forms of coprecipitation, microemulsion, biological nanoreactors, sol-gel and polyol methods. Various additional methods also exist for the controlled synthesis of MNPs including ultrasound irradiation (sonochemical synthesis), spray and laser pyrolysis.

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