Bhattacharya R.,Jadavpur University |
Bandyopadhyay S.,Maulana Abul Kalam Azad University of Technology
International Journal of Advanced Manufacturing Technology | Year: 2011
A review of the past research studies on the causes of bullwhip effect is presented in this paper. This paper is an effective study from the point of view that it presents a detailed classified study of the overall research studies on the effect of both the operational and the behavioral factors on bullwhip effect. A total of 19 causes of bullwhip effect have been shown here. We have identified the various gaps of research in the past research studies. An overview of the steps taken by the industries in order to tackle the bullwhip effect is also provided at the end of this paper. Directions for further research studies are also provided in each subsection of this study and at the end of this paper. © Springer-Verlag London Limited 2010.
Mukherjee I.,Jadavpur University |
Moulik S.P.,Jadavpur University |
Rakshit A.K.,Maulana Abul Kalam Azad University of Technology
Journal of Colloid and Interface Science | Year: 2013
Amphiphile adsorption at the air/water interface lowers the surface tension (γ) of the solution. After a critical surfactant concentration (C), γ becomes constant (with a break in the γ-logC plot), which is considered the critical micelle concentration (CMC). At very low amphiphile concentration, γ decreases slowly, forming a plateau, then decreases sharply and often nonlinearly by a co-operative adsorption process till the second plateau is reached at CMC. To get the Gibbs surface excess (Γ) of the amphiphile relative to water, a polynomial equation of appropriate degree needs to be used, since the drop in γ progresses with continuous changing slope, which maximizes at CMC and becomes zero afterward. Recent research has evidenced that a complete saturated Gibbs monolayer may not always form at CMC; there may be formation of multilayer of micelles below the Gibbs monolayer, which cannot be assessed by ST measurements. A method like neutron reflectometry (NR) can evaluate the Γ beyond CMC. A procedure for determining Γmax from tensiometric results is herein proposed. Amphiphiles do sometimes show a linear decline in γ with logC followed by a break with a plateau at CMC. There, a single slope leading to a single surface excess quantity is obtained for the Gibbs equation at all concentrations up to CMC. Possible reasons for such results are given. Current conflicting ideas and criticisms on the issue of Gibbs equation and determination of Γ and Γmax have been addressed. © 2012 Elsevier Inc.
Roy S.,Maulana Abul Kalam Azad University of Technology |
Thakur A.R.,West Bengal State University
Journal of Biomolecular Structure and Dynamics | Year: 2010
Homeodomains are one of the important families of eukaryotic DNA-binding motifs and provide an important model system for studying protein-DNA interactions. The crystal structure and NMR structure of the antennapedia homeodomain-DNA complex and comparison between them is available. Although earlier works have shown that the direct contacts and water mediated contacts are important for the binding and specificity. The detail dynamical structural characteristics of the complex, water mediating interactions in the complex and also the detail study of the free DNA and protein has not done. In the present paper we have reported the results of 20ns MD simulation of this complex with the presence of explicit water and also the 20ns MD simulation of the protein and the DNA separately in explicit water. The results show that the complex remains stable during the last 8ns of the simulation. The part of the protein which is interacting with the DNA has fewer fluctuations than other part of the protein. The pattern of water distribution around the interacting center has a typical pattern for this complex and it is quite different from the free protein and the free DNA. Water molecules penetrate into the interacting center during the simulation. Several water bridges have been identified which is responsible for recognition but not observed in the crystal structure. The recognized DNA sequence (14 mer) has been characterized by helical and step parameters. The correlated motions of the DNA and the protein in the complexed form and the free form has been analyzed. ©Adenine Press (2010).
Bandyopadhyay S.,Maulana Abul Kalam Azad University of Technology
International Journal of Advanced Manufacturing Technology | Year: 2010
This paper focuses on the facility location problem with two conflicting objectives. We observe that minimization of the total cost of a particular echelon may lead to the increase in the total cost of a supply chain as a whole. Thus, these conflicting objectives are required to be met together from a supply chain perspective. We have solved the problem formulated in mixed nonlinear programming by a multi-objective evolutionary algorithm (MOEA) known as non-dominated sorting algorithm, or NSGA II in short. Numerical example is provided to show the effect of the algorithm on the solution. © 2010 Springer-Verlag London Limited.
Chatterjee S.,Maulana Abul Kalam Azad University of Technology
Journal of Advanced Pharmaceutical Technology and Research | Year: 2015
Microbial alkaline protease has become an important industrial and commercial biotech product in the recent years and exerts major applications in food, textile, detergent, and pharmaceutical industries. By immobilization of microbes in different entrapment matrices, the enzyme produced can be more stable, pure, continuous, and can be reused which in turn modulates the enzyme production in an economical manner. There have been reports in support of calcium alginate and corn cab as excellent matrices for immobilization of Bacillus subtilis and Bacillus licheniformis, respectively. This study has been carried out using calcium alginate, κ-carrageenan, agar-agar, polyacrylamide gel, and gelatin which emphasizes not only on enzyme activity of immobilized whole cells by different entrapment matrices but also on their efficiency with respect to their reusability as first attempt. Gelatin was found to be the best matrix among all with highest enzyme activity (517 U/ml) at 24 h incubation point and also showed efficiency when reused.
Pal S.,Maulana Abul Kalam Azad University of Technology |
Saha C.,Maulana Abul Kalam Azad University of Technology
Journal of Biomolecular Structure and Dynamics | Year: 2014
Flavonoids are a class of plant secondary metabolites and among thousands of flavonoids few are considered as dietary flavonoids. Serum albumin (SA), the most abundant protein in plasma, functions as the most important carrier of vital drugs, including dietary flavonoids. The binding affinity of dietary flavonoids to SA is demonstrated to be governed by structure-affinity relationship (SAR) and its bioavailability. The present review summarizes the interactions of flavonoids categorized as flavanol, flavonol, flavone, isoflavone, flavanones, and anthocyanidins with SAs (bovine serum albumin and human serum albumin) in light of SAR. The key findings are: (1) the position and degree of hydroxylation highly influence the affinity of flavonoids to SAs, (2) glycosylation decreases and substitution of methoxy group increases the affinity of flavonoids for SAs, (3) catechin gallates have higher binding affinity to SAs than catechins and gallocatechins, (4) inorganic metal ions modulate the binding affinity of flavonoids to SAs, and (5) hydrophobic interaction plays a major role in the interactions of all flavonoids with SAs. © 2013 © 2013 Taylor & Francis.
Samanta T.B.,Maulana Abul Kalam Azad University of Technology
Indian Journal of Biotechnology | Year: 2012
The constraint in synthesis of ß-lactams by penicillin acylase is the hydrolysis of the activated acyl donor and the synthetic product. The thermodynamically controlled synthesis of ß-lactams deals with direct acylation of a nucleophile (6- APA, 7-ACA or 7-ADCA) by free acids in acidic pH and high concentration of solvent to achieve good yield. On the other hand, the kinetically controlled synthesis with esters is much faster. However, success and yield of kinetically controlled synthesis depend on combined application of an insolubilized catalyst, optimum pH of the reaction, addition of suitable solvent and high concentration of actvated acyl donor and ß-lactam nucleus. Water miscible solvents play an important role in the synthesis. The choice of solvent is guided by its inhibitory effect on enzyme activity and deleterious effect on enzyme stability. Synthetic yield of cefazolin in presence of water-miscible solvent is reduced, while the reaction carried in water- immiscible solvent markedly improves the yield of cefazolin, possibly due to reduction in hydrolysis of acyl donor and the product. Ethylene glycol inhibits more the hydrolysis of ampicillin than the hydrolysis of PGME and the synthetase/amidase ratio varies depending on the concentration of the solvent used. Hydrolytic vs synthetic activity of penicillin acylase is also influenced by water activity of the insolubilized catalyst. Shuffling of PA-encoding genes has been shown to improve the ß- lactam synthesis. Delineation of enzyme-solvent interaction needs close scrutiny to ensure further success in biocatalysis and synthesis of ß-lactams in particular.
Maulik A.,Maulana Abul Kalam Azad University of Technology |
Basu S.,Maulana Abul Kalam Azad University of Technology
Proteins: Structure, Function and Bioinformatics | Year: 2013
Polygalacturonase inhibiting proteins (PGIPs) are leucine-rich repeat (LRR) proteins from plants that are organized into multigene families. They act as specific inhibitors against Polygalacturonases (PGs) from phytopathogens and share high sequence identity within species. We performed in silico mutation (Q224K and V152G) in PGIP2 from Phaseolus vulgaris to corresponding residues of another member, PGIP1. This mutation is known to cause 100% loss of inhibition against the PG of fungus Fusarium phyllophilum (Fp). A comparative analysis between PGIP2 and the double mutant, using 50 ns molecular dynamics simulations explored structural difference affecting PG binding properties. Simulations revealed that the mutation at 224, strains this residue which acts as a lock for the PGIP-PG complex through main chain H-bond. Changes in secondary structural elements and strain in the bend region along the convex face of the solenoidal protein affected the flexibility of the mutant protein. At the concave interacting face of the mutant, subtle changes in the sidechain behavior of the PG-binding residues occurred in a concerted manner revealing flipping of aromatic rings to be crucial to avoid steric clash with FpPG in PGIP2. Docking PGIP2 and the mutant protein individually to FpPG illustrated the inability of the latter to inhibit FpPG leaving its active site free. Our study demonstrates that the effect of mutation affects the flexibility of the protein along the convex face, while binding specificity is altered through the concave face imparting minimal change in the typical structure supported by the LRRs. © 2013 Wiley Periodicals, Inc.
Maulana Abul Kalam Azad University of Technology | Date: 2011-07-28
Systems and methods for the bioremediation of soluble sulfates from an environmental effluent, include a first chamber including lactic acid bacteria immobilized on a first matrix and a second chamber including sulfate-reducing bacteria immobilized on a second matrix. The methods include providing the lactic acid bacteria a suitable medium for the production of lactic acid, which is directed to the culture of sulfate-reducing bacteria for use as a substrate/electron donor for the reduction of sulfates present in the environmental effluent.
Maulana Abul Kalam Azad University of Technology | Date: 2010-11-30
The disclosure describes systems and methods for determining a route in a network. A method according, to one embodiment includes determining a set of neighbor nodes that are within wireless communications range of a current node, determining that a route is needed from a source to a destination node, selecting a first neighbor node that is located closest to the destination node as the next hop in the route, and sending:a route-request message to the first neighbor node. The process continues on a hop-by-hop basis until reaching the destination node, whereupon a route-reply message is sent beck to the source node confirming that the route has been determined.