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Immobilization Imparts Stability to Watermelon Urease to Work in Water Miscible Organic Media
Om Prakash,Lata Sheo Bachan Upadhyay 한국생물공학회 2006 Biotechnology and Bioprocess Engineering Vol.11 No.2
The behaviour of alginate immobilized and soluble watermelon (Citrullus vulgaris) urease in water miscible organic solvents like, acetonitrile, dimethylformamide (DMF), ethanol, methanol, and propanol is described. The organic solvents exhibited a concentration dependent inhibitory effect on both the immobilized and the soluble urease in the presence of urea. Pretreatment of soluble enzyme preparations with organic solvents in the absence of substrate for 10 min at 30oC led to rapid loss in the activity, while similar pretreatment of immobilized urease with 50% (v/v) of ethanol, propanol, and acetonitrile was ineffective. Time-dependent inactivation of immobilized urease, both in the presence and in the absence of urea, revealed stability for longer duration of time even at very high concen-tration of organic solvents. The soluble enzyme, on the other hand, was rapidly inactivated even at fairly lower concentrations. The results suggest that the immobilization of watermelon urease in cal-cium alginate make it suitable for its application in organic media. The observations are discussed.
( Om Prakash ),( Seongwon Im ),( Alsayed Mostafa ),( Chungman Moon ),( Dong Hoon Kim ) 한국폐기물자원순환학회(구 한국폐기물학회) 2021 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2021 No.-
The treatment of sulfate rich wastewater leads to the failure of anaerobic digestion process due to high sulfide generation. Sulfide toxicity for the anaerobic digestion process is one the major concern that needs to overcome in order to recover the methanogenic potential of the sulfate-rich wastewater. In the present study, we tried to enhance the sulfide tolerance by promoting direct interspecies electron transfer (DIET) via electrical energy input (EEI). Two different operational conditions have been set to study the effect of sulfide on methanogenic process using up-flow anaerobic sludge blanket (UASB) reactor, comprising one control and one EEI reactor with an applied voltage of 0.6 V. The operation was continued for 194 days under different COD/SO<sub>4</sub> <sup>2-</sup> ratios. The EEI reactor exhibited maximum performance of 2.3 L CH<sub>4</sub>/L/d at the COD/SO<sub>4</sub> <sup>2-</sup> of 5 which is 15 % higher than the control. The free sulfide concentration were 251 and 283 mg S<sup>2-</sup>/L in control and EEI reactors, exceeding the inhibition threshold (50-200 mg S<sup>2-</sup>/L). Only EEI reactor could keep its advanced performance, by acquiring 12 and 15% higher sulfate removal and CH<sub>4</sub> productivity respectively than control reactor. Form this study, it can be claimed that DIET stimulation has potential for enriching efficient sulfate-metabolizing microbes. Furthermore, microbiological studies can enhance the depth of the mechanism and unearthed the reason behind the sulfide tolerance system supported by DIET promoting reactor.
Immobilization of Watermelon (Citrullus vulgaris) Urease in Agarose Gel for Urea Estimation
Om Prakash,Srilakshmi Puliga,Lata Sheo Bachan Upadhyay 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.2
Urease from dehusked seeds of watermelon was immobilized in 1.5% agarose gel with 53.9% entrapment. There was negligible leaching (< 10% at 4℃) and the same gel membrane could repeatedly be used for seven days. The immobilization exhibited no apparent change in the optimum pH but there was a significant decrease in the optimum temperature (50℃ as compared to 65℃ for soluble urease). The immobilized urease revealed an apparent Km of 9.3 ± 0.3 mM; 1.2 times lower than the soluble enzyme (11.4 ± 0.2 mM). Unlike soluble enzyme which was inhibited at 200 mM urea, the immobilized urease was inhibited at 600 mM of urea and above, and about 47% activity was retained at 2 M urea. The time-dependent thermal inactivation kinetics at 48 and 52℃ was found to be biphasic, in which half of the initial activity was destroyed more rapidly than the remaining half. These gel membranes were also used for estimating the urea content of the blood samples from the University hospital. The results obtained matched well with those obtained by the usual method employed in the clinical pathology laboratory. The significance of these observations is discussed.
Om Prakash,S. H. Hasan,Rajesh K. Pandey,Mahe Talat 한국생물공학회 2008 Biotechnology and Bioprocess Engineering Vol.13 No.2
Enzyme urease is extracted from the discarded seeds of pumpkin. Urease was purified to apparent homogeneity (5.2 fold) by heat treatment at 48 ± 1℃ and gel filtration through Sephadex G-200. Effect of model metal ions on the activity of the homogeneous enzyme preparation (sp. activity 353 U/mg protein, A280/A260 = 1.12) of soluble as well as immobilized enzyme was investigated. The soluble and immobilized urease has been used for the quantitative estimation of general water pollution with heavy metal ions like Hg²+, Cu²+, Cd²+, and Co²+. The measurements of the urease residual activity have been carried out in tris-acetate buffer after pre-incubation of model metal salt. The inhibition was found to be biphasic with an initial rapid loss of activity and remainder in slow phase of 10~15 min. The immobilization was done in 3.5% alginate beads leading to 86% of entrapment. There was no leaching of the enzyme over a period of 15 days at 4℃. The beads were fairly stable up to 50℃ and exhibited activity even at -10℃. The inhibition by these ions was non-competitive and irreversible, hence could not be restored by dialysis. Based on the values of inhibition constant Ki the heavy-metal ions were found to inhibit urease in the following order Hg²+ > Cu²+ > Cd²+ > Co²+.
A new iteration method for fixed point of nonexpansive mapping in uniformly convex Banach space
Omprakash Sahu,Amitabh Banerjee,Niyati Gurudwan 강원경기수학회 2022 한국수학논문집 Vol.30 No.4
The aim of this paper is to introduce a new iterative process and show that our iteration scheme is faster than other existing iteration schemes with the help of numerical examples. Next, we have established convergence and stability results for the approximation of fixed points of the contractive-like mapping in the framework of uniformly convex Banach space. In addition, we have established some convergence results for the approximation of the fixed points of a nonexpansive mapping.
Fabrication of Amorphous ZnO TFT with Tunable Channel Length
Omprakash S. S.,Naveen Kumar S. K. 한국전기전자재료학회 2022 Transactions on Electrical and Electronic Material Vol.23 No.1
The paper discusses the fabrication of amorphous zinc oxide (a:ZnO)-top gate top contact (the gate is situated on the top and the contacts are taken from the top) thin-film transistor (TFT) using spin-spray pyrolysis (SSP) unit. The solutions of ZnO and poly-vinyl-alcohol (PVA) are synthesized separately by the sol–gel method. The ZnO and PVA solution are coated over glass substrate using the SSP unit and drop-cast technique, respectively. These films are characterized using an optical profilometer, X-ray diffractometer, energy dispersive X-ray analysis, ultraviolet–visible spectrophotometry and Keithley measurement system. The XRD and EDAX measurement confirm the amorphous nature and composition respectively. The thickness of the ZnO and PVA film are 460 nm and 600 nm, respectively. The resistance of ZnO film is 100 KΩ. Using the absorption spectrum, we calculate the bandgap of ZnO and PVA thin film samples which are 3.05 eV and 3.9 eV respectively. The metal–insulator–metal (MIM) structure is fabricated using fluorine-doped tin oxide, PVA and silver paste. The MIM structure is characterized for the electrical parameters such as capacitance and dielectric constant (εr) which is found to be 0.4 μF and 8 respectively at 40 Hz frequency. The TFT is fabricated by depositing the aluminium as electrode, ZnO as channel layer and and PVA as insulator layer of TFT with different W/L ratios. The TFT parameters such as threshold voltage (V th ), on/off current ratio (I on/off ) and mobility are studied and presented. The results confirm that V th decreases with the shrinking of channel length. Current ratio I on/off increases with the reduction of the channel length due to the increase in on-current value.
( Omprakash Kaiwartya ),( Shiv Prakash ),( Abdul Hanan Abdullah ),( Ahmed Nazar Hassan ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.8
Energy consumption by large computing systems has become an important research theme not only because the sources of energy are depleting fast but also due to the environmental concern. Computational grid is a huge distributed computing platform for the applications that require high end computing resources and consume enormous energy to facilitate execution of jobs. The organizations which are offering services for high end computation, are more cautious about energy consumption and taking utmost steps for saving energy. Therefore, this paper proposes a scheduling technique for Minimizing Energy consumption using Adapted Genetic Algorithm (MiE-AGA) for dependent tasks in Computational Grid (CG). In MiE-AGA, fitness function formulation for energy consumption has been mathematically formulated. An adapted genetic algorithm has been developed for minimizing energy consumption with appropriate modifications in each components of original genetic algorithm such as representation of chromosome, crossover, mutation and inversion operations. Pseudo code for MiE-AGA and its components has been developed with appropriate examples. MiE-AGA is simulated using Java based programs integrated with GridSim. Analysis of simulation results in terms of energy consumption, makespan and average utilization of resources clearly reveals that MiE-AGA effectively optimizes energy, makespan and average utilization of resources in CG. Comparative analysis of the optimization performance between MiE-AGA and the state-of-the-arts algorithms: EAMM, HEFT, Min-Min and Max-Min shows the effectiveness of the model.
Approximation results of a three step iteration method in Banach space
Omprakash Sahu,Amitabh Banerjee 강원경기수학회 2023 한국수학논문집 Vol.31 No.3
The purpose of this paper is to introduce a new three-step iterative process and show that our iteration scheme is faster than other existing iteration schemes in the literature. We provide a numerical example supported by graphs and tables to validate our proofs. We also prove convergence and stability results for the approximation of fixed points of the contractive-like mapping in the framework of uniformly convex Banach space. In addition, we have established some weak and strong convergence theorems for nonexpansive mappings.
Omprakash Sahu,Amitabh Banerjee,Niyati Gurudwan 강원경기수학회 2023 한국수학논문집 Vol.31 No.1
The research article was published in your journal, Volume {\bf 30} (2022), N0. 4, pp. 665-678, but there are some citation errors on page numbers 670, 674-676.