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Shakoor A.,Bz University | Rizvi T.Z.,Quaid-i-Azam University | Nawaz A.,Quaid-i-Azam University
Journal of Materials Science: Materials in Electronics | Year: 2011

A series of polyaniline/montmorillonite clay (PANI-MMT) nanocomposites were synthesised by in situ polymerisation of aniline in acidic medium in the presence of varying amounts (from 1 to 30 wt%) of MMT and a substoichiometric amount of ammonium persulfate (APS). For a preferred molar ratio of monomer to oxidant of 2:1, the aniline was polymerised and largely incorporated into the MMT. The PANI-MMT nanocomposites were characterised and compared by wide-angle powder X-ray diffraction and UV-Vis spectroscopy. Raman spectroscopy was used to investigate the interaction between clay layers and the intercalated polymer chains. Room temperature AC conductivity was measured in the frequency range 30 Hz to 1 MHz. Pure PANI and all the composites exhibited a low frequency region of frequency independent AC conductivity followed by a high frequency dispersive region where the AC conductivity obeyed a fractional power law of frequency dependence. The fractional exponent n for all the nanocomposites is significantly high as compared to that of pure PANI; n = 0.9 for all the composites whereas for pure PANI n = 0.2. In pristine PANI the onset of the dispersive region ω c is at a much higher frequency (at 300 kHz) as compared to the nanocomposites in which ω c is about 10 kHz. © 2010 Springer Science+Business Media, LLC. Source


Alam M.A.,University of Veterinary and Animal Sciences | Maqbool A.,University of Veterinary and Animal Sciences | Nazir M.M.,Bz University | Lateef M.,University of Veterinary and Animal Sciences | And 2 more authors.
Veterinary Parasitology | Year: 2015

Entamoeba histolytica, a protozoan parasite that affects humans and other primates all over the world. It is a common waterborne pathogen in endemic areas that have fecal oral transmission cycle. The aim of the present study was to examine the prevalence of E. histolytica and other Entamoeba species cysts in three different dog populations. Fecal samples from 600 dogs were collected and processed to detect Entamoeba cysts using the triple fecal test (light microscopy) and fecal antigens of E. histolytica were detected using a fecal antigen ELISA (TechLab E. histolytica II). Because it is impossible to differentiate E. histolytica from Entamoeba dispar and E. moshkovskii, using light microscopy we referred to all cysts morphologically consistent with E. histolytica as E. histolytica/. dispar/. moskovskii to reflect this uncertainty. Samples from 197 household dogs without clinical signs, 122 samples from household dogs exhibiting clinical signs of diarrhea, dysentery and vomiting and 281 stray dogs with no specific clinical signs were examined. Entamoeba histolytica-like cysts were observed in 94 (15.6%, 95% CI. =. ±3.88) by triple fecal test microscopy and E. histolytica antigens were demonstrated in 66 (11%, 95% CI. =. ±4.41) by fecal antigen ELISA in 600 fecal samples. Significant differences (. P≤. 0.05) in prevalence were found between the three populations. Twenty (10.1%, 95% CI. =. ±7.86) and 11 (5.6%, 95% CI. =. ±7.70) of 197 fecal samples from household dogs without clinical signs were positive by microscopy and by antigen ELISA, respectively. Twenty-nine (23.8%, 95% CI. =. ±6.58) and 23 (18.8%, 95% CI. =. ±7.81) of 122 the fecal samples from household dogs with clinical signs were positive by microscopy and by antigen ELISA, respectively. Forty-five (16.01%, 95% CI. =. ±5.62) and 32 (11.3%, 95% CI. =. ±6.38) of 281 fecal samples from stray dogs were positive by microscopy and by fecal antigen ELISA, respectively. Dogs from the youngest age group (6 months to 1 year) were more likely to be E. histolytica antigen positive than were dogs from the other two older age groups, with a significant difference (. P≤. 0.05) between all age groups. Statistically, no significant (. P≥. 0.05) difference of prevalence was seen in male and female dogs. The local dogs had the highest prevalence rate of E. histolytica antigens (36 of 246, 14.2%, 95% CI. =. ±6.32) followed by imported breeds (11 of 115, 9.5%, 95% CI. =. ±10.4) and crossbred (19 of 239, 8.3%, 95% CI. =. ±7.47), indicating a significant (P≤. 0.05) trend of positivity between various breeds of dogs. These findings suggest that dogs may play an important role in the epidemiology of this pathogen. © 2014 Elsevier B.V. Source


Ranjha N.M.,Bz University | Ayub G.,Drug Testing Laboratory | Naseem S.,University of Punjab | Ansari M.T.,Bz University
Journal of Materials Science: Materials in Medicine | Year: 2010

In the present work crosslinked hydrogels based on chitosan (CS) and acrylic acid (AA) were prepared by free radical polymerization with various feed compositions using N,N methylenebisacrylamide (MBA) as crosslinking agent. Benzoyl peroxide was used as catalyst. Fourier transform infrared spectra (FTIR) confirmed the formation of the crosslinked hydrogels. This hydrogel is formed due to electrostatic interaction between cationic groups in CS and anionic groups in AA. Prepared hydrogels were used for dynamic and equilibrium swelling studies. For swelling behavior, effect of pH, polymeric and monomeric compositions and degree of crosslinking were investigated. Swelling studies were performed in USP phosphate buffer solutions of varying pH 1.2, 5.5, 6.5 and 7.5. Results showed that swelling increased by increasing AA contents in structure of hydrogels in solutions of higher pH values. This is due to the presence of more carboxylic groups available for ionization. On the other hand by increasing the chitosan content swelling increased in a solution of acidic pH, but this swelling was not significant and it is due to ionization of amine groups present in the structure of hydrogel. Swelling decreased with increase in crosslinking ratio owing to tighter hydrogel structure. Porosity and sol-gel fraction were also measured. With increase in CS and AA contents porosity and gel fraction increased, whereas by increasing MBA content porosity decreased and gel fraction increased. Furthermore, diffusion coefficient (D) and the network parameters i.e., the average molecular weight between crosslinks (M c), polymer volume fraction in swollen state (V2s), number of repeating units between crosslinks (Mr) and crosslinking density (q) were calculated using Flory-Rehner theory. Selected samples were loaded with a model drug verapamil. Release of verapamil depends on the ratios of CS/AA, degree of crosslinking and pH of the medium. The release mechanisms were studied by fitting experimental data to model equations and calculating the corresponding parameters. The result showed that the kinetics of drug release from the hydrogels in both pH 1.2 and 7.5 buffer solutions was mainly non-Fickian diffusion. © 2010 Springer Science+Business Media, LLC. Source


Khan I.U.,Government College University at Faisalabad | Khan I.U.,Bz University | Ayub G.,University of Strasbourg | Ranjha N.M.,University of Strasbourg
BioImpacts | Year: 2013

Amphiphilic copolymers are capable of forming core shell-like structures at the critical micellar concentration (CMC); hence, they can serve as drug carriers. Thus, in the present work, polymeric micelles based on novel chitosan derivative were synthesized. Methods: Block copolymer of palmitoyl glycol chitosan sulfate (PGCS) was prepared by grafting palmitoyl and sulfate groups serving as hydrophobic and hydrophilic fractions, respectively. Then, fourier transform infrared spectra (FTIR) and spectral changes in iodine/iodide mixture were carried out. Results: FTIR studies confirmed the formation of palmitoyl glycol chitosan sulfate (PGCS) and spectral changes in iodine/iodide mixture indicated CMC which lies in the range of 0.003-0.2 mg/ml. Conclusion: Therefore, our study indicated that polymeric micelles based on palmitoyl glycol chitosan sulphate could be used as a prospective carrier for water insoluble drugs. © 2013 by Tabriz University of Medical Sciences. Source


Siddique M.,Pakistan Institute of Nuclear Science and Technology | Ahmad I.,Bz University | Kanwal M.,Bz University | Ahmed E.,Pakistan Institute of Nuclear Science and Technology
Acta Physica Polonica A | Year: 2015

The Mössbauer spectroscopy and X-ray diffraction techniques have been used to investigate the effect of boron concentration on the structural and magnetic properties of as-quenched and heat-treated melt-spun alloys Nd7.5Pr2.5Fe90xBx (x = 6, 8, 10) produced by melt-spinning technique. X-ray diffraction and Mössbauer spectroscopy results indicate that as-prepared samples are completely amorphous in nature. The X-ray diffraction patterns of samples heat-treated at 700°C are indexed as Fe3B,-Fe, (NdPr)2Fe14B and Fe23B6 phases. The Mössbauer spectra of heat-treated samples are very complex and constituted a number of sextets and a quadrupole doublet. Two main phases are (NdPr)2Fe14B hard and t-Fe3B soft magnetic phases while κ-Fe and Nd23Fe6 are detected as minor phases. The average internal magnetic field decreases with the increase of boron content; more sharply in as-prepared and comparatively slowly in heat-treated samples. The X-ray diffraction and Mössbauer spectroscopy results are in good agreement with each other. Source

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