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  • Author: Rashid Ahmad, x
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Summary

The sorption of uranium(VI) ions onto PAN loaded PUF has been investigated. Quantitative sorption of uranium(VI) onto PAN loaded PUF was achieved after 30 minutes equilibration time from pH 7 buffer solution. The sorption data followed Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherms. Langmuir parameters Q = 45.3 ± 0.2 μmol g−1 and b = (76.2 ± 0.2) × 103 dm3 mol−1, Freundlich constants 1/n = 0.21 ± 0.01 and K F = 229 ± 21 μmol g−1 and D–R parameters β = −0.0015 ± 0.00005 kJ2 mol−2, X m = 72.23 ± 3.11 μmol g−1 and E = 18.3 ± 0.3 kJ mol-1 have been evaluated. The variation of sorption data with temperature gives ΔH = 176 ± 5 kJ mol−1, ΔS = 626 ± 17 J mol−1 K −1 and ΔG = −10.6 ± 0.7 kJ mol−1 at 298 K. The positive value of enthalpy (ΔH) and negative value of free energy (ΔG) show endothermic and spontaneous nature of sorption respectively. A number of solvents were tested to elute the uranium-PAN complex from the PAN loaded PUF, only amine solvents and cyclohexanone have the capability to desorb the complex. The sorption mechanism has been discussed.

Observation of Esterase-Like-Albumin Activity during N'-Nitrosodimethyl amine Induced Hepatic Fibrosis in a Mammalian Model

Aim: Hepatic fibrosis (HF) is characterized by irregular growth and amassing of fibrous scar tissues in the liver causing weakened hepatocytes metabolism and protein level alterations, including albumin. Albumin with Mr~68-70 kDa is unglycosylated soluble plasma protein with various biological roles. In this study, we demonstrate ‘esterase-like activity’ of albumin during NDMA-induced HF in rats.

Material and Methods: In rats, HF was induced by weekly i.p. injections of NDMA in doses of 10 mg/kg b.wt. Sera of controls (untreated) and treated rats were processed for biochemical tests, electrophoretic profiling and in-gel esterase activity localization using α, β-naphthyl acetates. H&E staining of liver sections (~ 5 μm) was done to confirm induction of HF.

Results: NDMA satisfactorily induces hepatic fibrosis within 21 days which is also evident by significant increase in SALP, SGOT, SGPT and bilirubin levels in rats. ‘Esterase-like activity’ of albumin detected in animal sera remains stable throughout the course of treatment irrespective of other biochemical changes.

Conclusion: During pathogenesis of HF, formation of stable esterase-albumin complex may have some important role and hence, prior recommending the use of albumin as diagnostic marker we propose further investigations to elucidate the mechanism of its formation.

Abstract

Coomassie Brilliant Blue R-250 (CBBR-250) is the most frequently used dye stain in protein research. However, relatively poor sensitivity and long application durations are the major limitations of this stain. In the present study, we have investigated the effect of pre-stain methanol washing on the sensitivity of the conventional CBB staining method. Concentrations of methanol ranging from 5 to 30% were prepared in 5% acetic acid. Pre-stain washing of SDS-gels using acetic acid (5%) and methanol were assessed at various timings and temperatures. Our results demonstrate that pre-stain washing by methanol greatly improves the sensitivity of the CBB stain and facilitates the visualization of low molecular weight components present in a complex muscle protein, actomyosin. The outcome of this study also revealed duration of pre-stain washing and temperature as other factors that determine the sensitivity of CBB staining method. Therefore, it is suggested that pre-stain washing with methanol may improve the sensitivity of CBB stain in SDS-PA gels.

The sorption of Tm(III) ions from aqueous solutions by 1-(2-pyridylazo)-2-naphthol (PAN) incorporated sol–gel matrices have been studied extensively using radiotracer and batch techniques. Maximum accumulation (∼98%) of Tm(III) ions (2.55×10-5 M) onto solid surface is achieved from pH 7 buffer solution in 30 min using 50 mg of PAN incorporated sol–gel matrices. The sorption data follow Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherms. The Langmuir constants Q = 123.6 ±3.6 μmol g-1 and b = (19.2 ± 2.1)×104 dm3 mol-1 have been computed. Freundlich constants l/n = 0.56 ± 0.04 and C m = 45.4 ± 6.5 mmol g-1 have been estimated. Sorption capacity 1.13 ± 0.001 mmol g-1, β = -0.0035 ± 0.0001 kJ2 mol-2 and energy 11.95 ± 0.2 kJ mol-1 have been evaluated using D–R isotherm. The variation of sorption with temperature yields ΔH = 31.7 ± 0.8 kJ mol-1, ΔS = 128.5 ± 3 J mol-1 K-1 and ΔG = -6.5 ± 0.1 kJ mol-1 at 298 K reflecting the endothermic and spontaneous nature of sorption. Divalent Pb(II), Ba(II) and Mg(II) and monovalent chloride and K(I) increase the sorption while oxalate, citrate, disulfite and tartrate reduce the sorption significantly.

Abstract

This manuscript reports the synthesis and characterization of caprylpyrazolone tailored silica nanospheres, synthesized through sol–gel procedure by activating the silica nanospheres with organosilane precursor and grafting with caprylpyrazolone. Its successful attachment to the silica is confirmed by FTIR, TGA and elemental techniques. The feasibility of the synthesized nanospheres as adsorbent was systematically checked by elimination of trace level of Cr(III) from aqueous medium, using radiotracer technique. A number of factors such as effect of pH, agitation time, adsorbent and adsorbate dosage were optimized to guarantee the use of the adsorbent for practical use. Various counter ions were added to the matrix solution to check the selectivity of the synthesized sorbent. Various rate equations and adsorption isotherms such as Freundlich, D-R and Langmuir were employed to suggest the mechanistic pathway of the adsorption process. The Cr(III) extraction was monitored at room and elevated temperatures and thermodynamic parameters such as change in enthalpy, entropy, and Gibbs free energy of the metal ion uptake were computed. The removal of Cr(III) is endothermic (∆H=30.00 J mol−1 K−1) and spontaneous (∆S=105.43 J mol−1 K−1) in nature. Application of the adsorbent to real water samples demonstrated the practical utility of the adsorbent. The sorbent displayed good stability. Its cleaning efficiency is not significantly affected after various adsorption-desorption cycles and so it can be used repeatedly.

Abstract

The Fourier pseudo-spectral method has been studied for a one- dimensional coupled system of viscous Burgers equations. Two test problems with known exact solutions have been selected for this study. In this paper, the rate of con- vergence in time and error analysis of the solution of the first problem has been studied, while the numerical results of the second problem obtained by the present method are compared to those obtained by using the Chebyshev spectral collocation method. The numerical results show that the proposed method outperforms the conventional one in terms of accuracy and convergence rate.

Abstract

In this paper, the vibration analysis in terms of modal and harmonic responses are investigated for the power station structure of Kenyir Dam in Terengganu, Malaysia. Modal analysis is carried out to provide the dynamic characteristics of the power station which includes the natural frequencies and mode shapes. Meanwhile, the harmonic response analysis is performed by applying the force to the structure to obtain the Frequency Response Function (FRF) in certain range of frequencies. A real scale three-dimensional (3D) model of the Kenyir Dam power station is constructed using SolidWorks software and imported to ANSYS software for the Finite Element (FE) analysis. A proper boundary condition is taken into consideration to demonstrate the real behaviour of the power station structure. From the results, six most significant natural frequencies and mode shapes including the FRF in all three axes are selected. The highest natural frequency value occurred at 5.4 Hz with the maximum deflection of 0.90361 m in the z axis direction. This value is important in order to verify whether the structure can overcome the resonance phenomenon from the external disturbance forces in the future.

Abstract

There are diverse lifetime models available to the researchers to predict the uncertain behavior of random events but at times they fail to provide adequate fit for some complex and new data sets. New probability distributions are emerging as lifetime models to meet this ever growing demand of modeling complex real world phenomena from different sciences with better efficiency. Here, in this manuscript we shall compose Ailamujia distribution with that of power series distribution. This newly developed distribution called Ailamujia power series distribution reduces to four new special lifetime models on simple specific function parametric setting. Apart from this some important mathematical properties in the form of propositions will also be discussed. Furthermore, characterization and some statistical properties that include mgf, moments, and parameter estimation have also been discussed. Finally, the potency of newly proposed model has been analyzed statistically and graphically and it has been established from the statistical analysis that newly proposed model offers a better fit when it comes to model some lifetime data set.