Scientific Information Center

Karachi, Pakistan

Scientific Information Center

Karachi, Pakistan
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Aftab K.,Pakistan Council of Scientific and Industrial Research PCSIR | Ali M.D.,Pakistan Council of Scientific and Industrial Research PCSIR | Aijaz P.,Pakistan Council of Scientific and Industrial Research PCSIR | Beena N.,Pakistan Council of Scientific and Industrial Research PCSIR | And 4 more authors.
International Food Research Journal | Year: 2011

The quantitative determination of essential and trace elements via advanced X-ray fluorescence (XRF) Spectroscopic technique, in this response three different lemon grass samples were collected from different fields, among the analysed sample the highest amount of potassium (K) 53.40%, calcium (Ca) 26.19%, and silicon (Si) 10.01% were determined, while the second highest amount of sodium (Na) and magnesium (Mg) were found 2.57% and 2.05% respectively, the remaining were at below 2%. The standard deviations of samples are below than 5%. The validity and accuracy of the optimized procedure was checked by analysis of the certified reference materials (CRM)/literature values by XRF technique. © 2011.

Saify Z.S.,University of Karachi | Rasheed H.,University of Karachi | Mushtaq N.,University of Karachi | Nisa M.,University of Karachi | And 4 more authors.
Archives of Pharmacal Research | Year: 2012

Piperidine derivatives are known to exhibit analgesic activities and are likely to possess the ability to block the effects of prostaglandins through inhibition of downstream signaling pathways. The present study investigated the activity of five derivatives (PD2-6) of 4-(4′-bromophenyl)-4-piperidinol (PD1), against pain and platelet aggregation mediated by the release of prostaglandins and thromboxane A2, respectively. The results showed that compound PD1 and its two phenacyl derivatives PD3 and PD5 exhibited a highly significant analgesic effect (p < 0.01), whereas PD4 and PD6 also showed significant activity. PD3, the most active analgesic compound when docked to the opioid receptor, had interactions between the oxygen of its nitro group and the amino group of ARG 573, indicating a distance of 1.2563 Å. The antiplatelet data showed that compound PD5 (4-(4′-bromo-phenyl)-4-hydroxy- 1-[2-(2″,4″-dimethoxyphenyl)-2-oxo-ethyl]-piperidinium bromide) had an IC50 = 0.06 mM, which was the most active compound, whereas PD3 was the second most active compound against platelet aggregating factor-induced aggregation with an IC50 = 80 mM. Acetyl salicylic acid (IC 50 = 150 μM) was used as a positive control. © 2012 The Pharmaceutical Society of Korea and Springer Science+Business Media Dordrecht.

Saify Z.S.,University of Karachi | Nisa M.,University of Karachi | Azhar K.F.,Scientific Information Center | Azim M.K.,University of Karachi | And 6 more authors.
Natural Product Research | Year: 2011

Piperidine derivatives are reported to exhibit a variety of pharmacological activities. In this article, synthesis and aspartic protease inhibitory activity of three nitrophenacyl derivatives of N-methyl-4-hydroxy piperidine are reported. Enzyme assays showed that the attachment of a nitro group in the benzene ring plays an important role in the inhibition of plasmepsin-II of Plasmodium falciparum. The compound 1-methyl-1-(4-nitrophenacyl)-4- hydroxypiperidinium bromide (3), consisting of a nitro group at the para position, was the most active at the concentration of 1.0 μM. The activity of the compounds was evaluated through the observed orientation and diagrammatic representation of nitrophenacyl derivatives of 4-hydroxy piperidine. © 2011 Copyright Taylor and Francis Group, LLC.

Sarwar A.,Fuel Research Center | Khan M.N.,University of Karachi | Azhar K.F.,Scientific Information Center
Energy Sources, Part A: Recovery, Utilization and Environmental Effects | Year: 2014

The samples of Thar coalfield were characterized using a thermogravimetric analyzer, atomic absorption spectrophotometer, X-ray diffractometer, Fourier transform infrared spectra, and scanning electron microscopy-energy dispersive x-ray spectroscopy analysis. The samples were ranked as lignite and subbituminous according to American Society for Testing and Materials standard classification. Differential thermogravimetric analysis results specified chemical reactivity of coal at the primary devolatilization region (257-412°C) and secondary devolatilization region (741-900°C). The minerals identified were quartz, kaolinite, dikite, halloysite, gold copper indium, graphite hydrogen nitrate, and magnesium vanadium molybdenum oxide. X-ray diffraction study confirmed the presence of mineral constituents as indicated by microscopic investigation. Fourier transform infrared spectra identified C=C aromatic groups at 1,500-1,700 cm-1 as maturity indicator and 2,800-3,000 cm-1 and 2,300 cm-1 as aliphatic stretching regions. The peaks of quartz and kaolinite were observed at 900-1,100 cm-1. Strong correlations between mineral matter-SiO 2 (r 2 = 0.808) and Al2O3-SiO2 (r 2 = 0.957) indicates Al and Si as the dominant inorganic components. Cluster analysis appeared as an additional tool for coal ranking based on their physicochemical properties. © 2014 Copyright Taylor and Francis Group, LLC.

Sarwar A.,Fuel Research Center | Nasiruddin Khan M.,University of Karachi | Azhar K.F.,Scientific Information Center
Journal of Thermal Analysis and Calorimetry | Year: 2012

The concept of weighted mean activation energy has been used to assess the reactivity of Thar coal in terms of pyrolytic and combustion behavior using non-isothermal thermogravimetry. The samples were characterized as low sulfur and high volatile lignite to subbituminous coal. Modified Coats-Redfern method was applied to analyze the kinetic data of both processes. Thermal degradation of the samples studied was explained by three independent first-order kinetic steps. The good correlation coefficients for the independent first-order reaction models show the complexity of the overall process. The activation energy for pyrolysis reaction ranges from 19.20-63.55 to 23.68-54.49 kJ mol -1 for combustion profile. The samples of different rank were classified applying chemometric approach on the reactivity parameters. Principal component analysis was found as a statistical tool to organize the coal samples in accordance to ASTM classification. This study broadens the scope of thermal analysis in the field of coal utilization by assessing coal reactivity. © 2011 Akadémiai Kiadó, Budapest, Hungary.

Dukhovny V.A.,Scientific Information Center | Ziganshina D.,Scientific Information Center
Irrigation and Drainage | Year: 2011

Given the growing destabilizing factors (climate change demographic growth financial instability desertification) the water supply for future development of our planet will become even more an issue. In order to guarantee access to water for different countries regions and individuals it is necessary to elaborate and adopt for governance in general a body of legal financial institutional and economic tools and mechanisms that would become an indisputable set of rules as a kind of Bible for modern humankind and as a way to survive. Water governance should prevent any attempt to use water as a means of political or economic pressure or as a good like oil transformed into the subject of profiteering. Water is a holy thing and we all must take care of and save it so that everyone might have access to water in adequate quantity and quality. © 2011 John Wiley & Sons Ltd.

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