Chitosan‐coated alginate–polyvinyl alcohol beads for encapsulation of silicone oil containing pyrene: a novel method for biodegradation of polycyclic aromatic hydrocarbons

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are potential hazards in the environment owing to their toxic, carcinogenic and recalcitrant nature. Biodegradation of these compounds, although effective compared with other treatment techniques, is problematic owing to its low aqueous solubility and negligible bioavailability. The present study reports a novel method for biodegradation of PAHs using an encapsulated form of the pollutant in chitosan‐coated alginate–polyvinyl alcohol (PVA) beads. RESULTS: A suitable combination of 3% (w/v) PVA, 100 g L^?1 non‐ionic surfactant Brij 30 and 0.3 silicone oil fraction in the formulation was found to be optimal in the preparation of stable emulsion. The emulsion obtained was admixed with alginate (3% w/v) to prepare suitably sized microspheres by an emulsion gelation technique, which were later coated with chitosan to yield a maximum pyrene encapsulation efficiency of 90.7%. Pyrene in silicone oil at concentration as high as 2 g L^?1, when delivered through the chitosan coated alginate–PVA beads, was completely degraded by Mycobacterium frederiksbergense within 10 days without any significant lag phase. CONCLUSION: Using chitosan‐coated alginate–PVA beads sustained release of pyrene and subsequent biodegradation by M. frederiksbergense were achieved. Using the present system, complete degradation of pyrene was attained even at its very high initial concentration and within a short time period. Further advantage offered by this system seems to be negligible toxic effect of pyrene and solvents on the degrading microorganisms since these were in an encapsulated form and were not in direct contact with the organism. Copyright © 2010 Society of Chemical Industry     

India’s national food security programme: a strategic insight

Indian National Food Security Programme, with a goal to provide highly subsidized food grains to more than 800 million people in every nook and corner of the vast country, faces strategic challenges related to production, procurement, storage, transportation, distribution, finance, and organization. While the production issues are related to low yield, small farm size, and lack of financial support, the procurement process is skewed and lacks integration with the markets. The storage facilities are inadequate and are non-optimally located. Transportation facilities lack coordination leading to multiple loading and unloading of the food grains. Leakage and improper distribution of food grains are also big challenges. Very high subsidy, inefficient processes, and a large work force have brought to the fore the question of financial viability of the programme. There are also organizational issues related to payment disparity and resistance to labor reforms. The paper has also given a framework for efficient implementation of the programme using cloud system with effective procurement and stock management policy measures.     

High Na+ conducting Na3Zr2Si2PO12/Na2Si2O5 composites as solid electrolytes for Na+ batteries

Sodium superionic conductor Na₃Zr₂Si₂PO₁₂ (NZSP) is a promising material as a solid electrolyte for sodium-ion batteries. The highest conductivity of ∼1.0 mS/cm at room temperature (RT) was reported for the compound with a Na content of approximately 3.3 per formula unit (f. u.) and when the material is synthesized with a final sintering temperature ≥1220°C. Herein, we propose a new synthesis method to enhance the conductivity of the NZSP by liquid-phase sintering with the optimum amount of additive of amorphous-Na₂Si₂O₅. In this regard, a series of composite materials were prepared by mixing Na₃Zr₂Si₂PO₁₂ with amorphous-Na₂Si₂O₅ (NZSP/NS-x wt.%; with x = 0.0, 2.5, 5.0, 7.5, 10.0) and sintering at a lower temperature of 1150°C. Enhanced conductivity of 1.7 mS/cm at RT has been achieved for the Na₃Zr₂Si₂PO₁₂/Na₂Si₂O₅-5.0 wt.% (NZSP/NS-5.0) composite. The effects of additives on the NZSP phase formation, microstructure, and ion conductivity have been investigated by XRD, MAS NMR, SEM, and impedance spectroscopy. Our study demonstrates that the higher conductivity of the NZSP/NS-5.0 composite is caused by the combined effect of increased Na content in the NZSP phase (by diffusion of Na⁺ ions from the liquid phase of NS to bare NZSP phase), higher density, and microstructures with lesser pores.     

Antibiotic production by Erwinia herbicola Eh1087: its role in inhibition of Erwinia amylovora and partial characterization of antibiotic biosynthesis genes

Mutants of Erwinia herbicola Eh1087 (Ant-), which did not produce antibiotic activity against Erwinia amylovora, the fire blight pathogen, were selected after TnphoA mutagenesis. In immature pear fruit Ant- mutants grew at the same rate as wild-type strain Eh1087 but did not suppress development of the disease caused by E. amylovora. These results indicated that antibiosis plays an important role in the suppression of disease by strain Eh1087. All of the Ant- mutations obtained were located in a 2.2-kb region on a 200-kb indigenous plasmid. Sequence analysis of the mutated DNA region resulted in identification of six open reading frames, designated ORF1 through ORF6, four of which were essential to antibiotic expression. One gene was identified as a gene which encodes a translocase protein which is probably involved in antibiotic secretion. A sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of plasmid proteins produced in Escherichia coli minicells confirmed the presence of proteins whose sizes corresponded to the sizes of the predicted open reading frame products.     

Optimization of Hot Rolled Coil Widths Using a Genetic Algorithm

This paper focuses on the assortment problem in the steel industry; with the help of the genetic algorithm, it attempts to determine the optimum width of the parent stock given a set of forecasted customer widths so that the trim loss is minimized. For each given set of forecasted customer widths, an attempt is made to find a single width of the mother coil to be manufactured and kept in stock. In the genetic algorithm, six different selection schemes are considered. A number of test problems are taken up for different selection schemes. Evaluated against the maximum fitness value, the optimal mother coil width, and the generation number at which they are achieved, the elitism selection scheme shows consistently good results in all the test problems compared with the other selection mechanisms.     

A novel large value ac capacitor using two dc capacitors

The paper proposes a novel power electronic circuit to realize bipolar ac capacitor using two unipolar dc capacitors. Experiments are successfully carried out to verify the validity of the proposed circuit. Copyright © 2008 John Wiley & Sons, Ltd.     

Calcium-permeable AMPA receptors mediate long-term potentiation in interneurons in the amygdala

Fear conditioning is a paradigm that has been used as a model for emotional learning in animals. The cellular correlate of fear conditioning is thought to be associative N-methyl-D-aspartate (NMDA) receptor-dependent synaptic plasticity within the amygdala. Here we show that glutamatergic synaptic transmission to inhibitory interneurons in the basolateral amygdala is mediated solely by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. In contrast to AMPA receptors at inputs to pyramidal neurons, these receptors have an inwardly rectifying current-voltage relationship, indicative of a high permeability to calcium. Tetanic stimulation of inputs to interneurons caused an immediate and sustained increase in the efficacy of these synapses. This potentiation required a rise in postsynaptic calcium, but was independent of NMDA receptor activation. The potentiation of excitatory inputs to interneurons was reflected as an increase in the amplitude of the GABA(A)-mediated inhibitory synaptic current in pyramidal neurons. These results demonstrate that excitatory synapses onto interneurons within a fear conditioning circuit show NMDA-receptor independent long-term potentiation. This plasticity might underlie the increased synchronization of activity between neurons in the basolateral amygdala after fear conditioning.     

Quasi-passive filter for harmonic filtering

To overcome the limitations of conventional shunt passive filters, a quasi-passive filter has been proposed in this paper. It comprises of a parallel and series tuned LC tank circuit. Unlike the conventional shunt passive filter, the quasi-passive filter utilizes a large value ac capacitor. Unipolar dc capacitors and power semiconductor devices are used to realize the large value ac capacitor. The operation of the quasi-passive filter is simple and it does not require the complex control methods of active power filters. The proposed quasi-passive filter is verified through analysis and simulation.     

Aggregate procurement,production, and shipment planning decision problem for a three-echelon supply chain using swarm-based heuristics

Supplier selection is deemed as a crucial strategic decision-making activity in building a competitive edge. Firms prefer to operate with a few trusted suppliers, selected from a bigger pool of vendors. The chosen suppliers are the ones whose commitments are best oriented in realising the business goals of the company. At the same time enterprise targets cannot be achieved in the absence of cost-effective inventory management policies. This has created the inevitable need for aggregate production and distribution planning. Even more competitive strategy would be integrating procurement planning with production-distribution scheduling. We address the problem of integrated procurement, production and shipment planning for a supply chain, spanning over three echelons. Supplier order scheduling is combined with a production-shipment planning process to realise a minimum cost operations policy. Two recently developed swarm heuristics are employed to search for the near optimal solution of the mathematical model, which is developed to capture the aggregate planning problem.     

A decision framework for the analysis of green supply chain contracts: An evolutionary game approach

The overwhelming growth in the struggle between economy and ecology has led managerial research to promote methodologies to reap profits ensuring sustainability of the ecosystem thus venturing into the novel domain incorporating sustainability with supply chain management and coordination. In this paper, we look for a synergetic alliance between the environmental and commercial benefits by establishing coordination between the producer and the retailer to adjudicate their strategies to trigger green practices with the focus on maximizing economic profits by leveraging upon the product’s greenness. A two player game has been developed to stand synonymous to the situation considered. Special considerations have been devised to augment the analysis with the consumer psychology towards the green products to establish a practical outlook involving the greenness and economic returns. Evolutionary dynamics has been adopted extensively to locate the optimal and the most stable point offering the best economic gains. The economically suitable solutions are then substantiated on an existing sustainability metric and hence we aim to offer a holistic view into supply chain dynamics from the perspective of environmental management. The insights drawn provide managerial implications and advantages of having environment as a key focus along with business motives.