A queuing approach for inventory planning with batch ordering in multi-echelon supply chains

This paper presents stylized models for conducting performance analysis of the manufacturing supply chain network (SCN) in a stochastic setting for batch ordering. We use queueing models to capture the behavior of SCN. The analysis is clubbed with an inventory optimization model, which can be used for designing inventory policies . In the first case, we model one manufacturer with one warehouse, which supplies to various retailers. We determine the optimal inventory level at the warehouse that minimizes total expected cost of carrying inventory, back order cost associated with serving orders in the backlog queue, and ordering cost. In the second model we impose service level constraint in terms of fill rate (probability an order is filled from stock at warehouse), assuming that customers do not balk from the system. We present several numerical examples to illustrate the model and to illustrate its various features. In the third case, we extend the model to a three-echelon inventory model which explicitly considers the logistics process.

A Bayesian incentive compatible mechanism for decentralized supply chain formation

In this paper we consider a decentralized supply chain formation problem for linear multi-echelon supply chains when the managers of the individual echelons are autonomous, rational, and intelligent. At each echelon, there is a choice of service providers and the specific problem we solve is that of determining a cost-optimal mix of service providers so as to achieve a desired level of end-to-end delivery performance. The problem can be broken up into two sub-problems following a mechanism design approach: (1) Design of an incentive compatible mechanism to elicit the true cost functions from the echelon managers; (2) Formulation and solution of an appropriate optimization problem using the true cost information. In this paper we propose a novel Bayesian incentive compatible mechanism for eliciting the true cost functions. This improves upon existing solutions in the literature which are all based on the classical Vickrey-Clarke-Groves mechanisms, requiring significant incentives to be paid to the echelon managers for achieving dominant strategy incentive compatibility. The proposed solution, which we call SCF-BIC (Supply Chain Formation with Bayesian Incentive Compatibility), significantly reduces the cost of supply chain formation. We illustrate the efficacy of the proposed methodology using the example of a three echelon manufacturing supply chain.

Indian Nanoelectronics Users Program An Outreach Vehicle to Expedite Nanoelectronics Research in India

The worldwide research in nanoelectronics is motivated by the fact that scaling of MOSFETs by conventional top down approach will not continue for ever due to fundamental limits imposed by physics even if it is delayed for some more years. The research community in this domain has largely become multidisciplinary trying to discover novel transistor structures built with novel materials so that semiconductor industry can continue to follow its projected roadmap. However, setting up and running a nanoelectronics facility for research is hugely expensive. Therefore it is a common model to setup a central networked facility that can be shared with large number of users across the research community. The Centres for Excellence in Nanoelectronics (CEN) at Indian Institute of Science, Bangalore (IISc) and Indian Institute of Technology, Bombay (IITB) are such central networked facilities setup with funding of about USD 20 million from the Department of Information Technology (DIT), Ministry of Communications and Information Technology (MCIT), Government of India, in 2005. Indian Nanoelectronics Users Program (INUP) is a missionary program not only to spread awareness and provide training in nanoelectronics but also to provide easy access to the latest facilities at CEN in IISc and at IITB for the wider nanoelectronics research community in India. This program, also funded by MCIT, aims to train researchers by conducting workshops, hands-on training programs, and providing access to CEN facilities. This is a unique program aiming to expedite nanoelectronics research in the country, as the funding for projects required for projects proposed by researchers from around India has prior financial approval from the government and requires only technical approval by the IISc/ IITB team. This paper discusses the objectives of INUP, gives brief descriptions of CEN facilities, the training programs conducted by INUP and list various research activities currently under way in the program.

Integrated Magnetics-Based Multisource Quality AC Power Supply

This paper proposes a method of sharing power/energy between multiple sources and multiple loads using an integrated magnetic circuit as a junction between sources and sinks. It also presents a particular use of the magnetic circuit as an ac power supply, delivering sinusoidal voltage to load irrespective of the presence of the grid, taking only active power from the grid. The proposed magnetic circuit is a three-energy-port unit, viz.: 1) power/energy from grid; 2) power energy from battery-inverter unit; and 3) power/energy delivery to the load in its particular application as quality ac power supply (QPS). The product provides sinusoidal regulated output voltage, input power-factor correction, electrical isolation between the sources and loads, low battery voltage, and control simplicity. Unlike conventional series-shunt-compensated uninterruptible power supply topologies with low battery voltage, the isolation is provided using a single magnetic circuit that results in a smaller size and lower cost. The circuit operating principles and analysis, as well as simulation and experimental results, are presented for this QPS.

Laser receptive polyelectrolyte thin films doped with biosynthesized silver nanoparticles for antibacterial coatings and drug delivery applications

We report a simple method to fabricate multifunctional polyelectrolyte thin films to load and deliver the therapeutic drugs. The multilayer thin films were assembled by the electrostatic adsorption of poly (allylamine hydrochloride) (PAH) and dextran sulfate (DS). The silver nanoparticles (Ag NPs) biosynthesized from novel Hybanthus enneaspermus leaf extract as the reducing agent were successfully incorporated into the film. The biosynthesized Ag NPs showed excellent antimicrobial activity against the range of enteropathogens, which could be significantly enhanced when used with commercial antibiotics. The assembled silver nano composite multilayer films showed rupture and deformation when they are exposed to laser. The Ag NPs act as an energy absorption center, locally heat up the film and rupture it under laser treatment. The antibacterial drug, moxifloxacin hydrochloride (MH) was successfully loaded into the multilayer films. The total amount of MH release observed was about 63% which increased to 85% when subjected to laser light exposure. Thus, the polyelectrolyte thin film reported in our study has significant potential in the field of remote activated drug delivery, antibacterial coatings and wound dressings. (C) 2013 Elsevier B.V. All rights reserved.

A cationic cholesterol based nanocarrier for the delivery of p53-EGFP-C3 plasmid to cancer cells

The p53 protein mediated anti-tumor strategy is limited due to the lack of suitable delivery agent with insignificant immunogenic response, serum compatibility, and early and easy detection of the transfected cell population. To overcome these problems, we generated a p53-EGFP-C3 fusion construct which expressed easily detectable green fluorescence protein (GFP) and allowed an estimation of p53 mediated anti-tumor activity. A mixture of cationic cholesterol gemini (Choi-5L) with natural lipid, DOPE (molar ratio 1:4), acronymed as Chol-5LD, formed a nano-liposome as characterized by various physical methods. The prepared clone was evaluated for the expression of GFP and functional p53 in HeLa and two additional cell lines with varied p53 status namely, H1299 (p53(-/-)) and HEK293T (p53(+/+)). Transfected cells were screened using RT-PCR, Western blotting, FACS analysis, MTT, Trypan blue assay and visualized under a fluorescence microscope. The p53-EGFP-C3 fusion protein induced apoptosis in cancer cells as evident from DNA fragmentation, cell cycle analysis, Annexin-V staining and PARP cleavage assays. The transfection and apoptosis induction efficiency of Chol-5LD was significantly higher than commercial reagents Lipofectamine2000 and Effectene irrespective of the cell lines examined. Further it significantly decreases the xenograft tumor volume in nude mice tumors via apoptosis as observed in H&E staining. (C) 2013 Elsevier Ltd. All rights reserved.

Co-liposomes of redox-active alkyl-ferrocene modified low MW branched PEI and DOPE for efficacious gene delivery in serum

Herein, we present six new lipopolymers based on low molecular weight, branched polyethylenimine (BPEI 800 Da) which are hydrophobically modified using ferrocene terminated alkyl tails of variable lengths. The effects of degree of grafting, spacer length and the redox state of ferrocene in the lipopolymers on the self assembly properties were investigated in detail by TEM, AFM, DLS and zeta potential measurements. The assemblies displayed an oxidation induced increase in the size of the aggregates. The co-liposomes comprising the lipopolymer and a helper lipid, 1,2-dioleoyl phosphatidyl ethanolamine (DOPE), showed excellent gene (pDNA) delivery capability in a serum containing environment in two cancer cell lines (HeLa and U251 cells). Optimized formulations showed remarkably higher transfection activity than BPEI (25 kDa) and were also significantly better than a commercial transfection reagent, Lipofectamine 2000 as evidenced from both the luciferase activity and GFP expression analysis. Oxidation of ferrocene in the lipopolymers led to drastically reduced levels of gene transfection which was substantiated by reduced cellular internalization of fluorescently labelled pDNA as detected using confocal microscopy and flow cytometry. Moreover, the transfection inactive oxidized lipopolyplexes could be turned transfection active by exposure to ascorbic acid (AA) in cell culture medium during transfection. Endocytosis inhibition experiments showed that gene expression mediated by reduced formulations involved both clathrin and caveolae mediated pathways while the oxidized formulations were routed via the caveolae. Cytotoxicity assays revealed no obvious toxicity for the lipopolyplexes in the range of optimized transfection levels in both the cell lines studied. Overall, we have exploited the redox activity of ferrocene in branched PEI-based efficient polymeric gene carriers whose differential transfection activities could be harnessed for spatial or temporal cellular transfections.

Efficacious redox-responsive gene delivery in serum by ferrocenylated monomeric and dimeric cationic cholesterols

Herein, we present the design and synthesis of new redox-active monomeric and dimeric (gemini) cationic lipids based on ferrocenylated cholesterol derivatives for gene delivery. The cationic cholesterols are shown to be transfection efficient after being formulated with the neutral helper lipid DOPE in the presence of serum (FBS). The redox activity of the resulting co-liposomes and their lipoplexes could be regulated using the alkanyl ferrocene moiety attached to the ammonium head groups of the cationic cholesterols. Atomic force microscopy (AFM), dynamic light scattering (DLS) and zeta potential measurements were performed to characterize the co-liposomal aggregates and their complexes with pDNA. The transfection efficiency of lipoplexes could be tuned by changing the oxidation state of the ferrocene moiety. The gene transfection capability was assayed in terms of green fluorescence protein (GFP) expression using pEGFP-C3 plasmid DNA in three cell lines of different origins, namely Caco-2, HEK293T and HeLa, in the presence of serum. The vesicles possessing ferrocene in the reduced state induced an efficient transfection, even better than a commercial reagent Lipofectamine 2000 (Lipo 2000) as evidenced by flow cytometry and fluorescence microscopy. All the co-liposomes containing the oxidized ferrocene displayed diminished levels of gene expression. Gene transfection events from the oxidized co-liposomes were further potentiated by introducing ascorbic acid (AA) as a reducing agent during lipoplex incubation with cells, leading to the resumption of transfection activity. Assessment of transfection capability of both reduced and oxidized co-liposomes was also undertaken following cellular internalization of labelled pDNA using confocal microscopy and flow cytometry. Overall, we demonstrate here controlled gene transfection activities using redox-driven, transfection efficient cationic monomeric and dimeric cholesterol lipids. Such systems could be used in gene delivery applications where transfection needs to be performed spatially or temporally.

Hydrological importance of sacred forest fragments in Central Western Ghats of India

Sacred groves are patches of forests of special spiritual significance to humans, offering also a diverse range of ecological and environmental services. We have attempted here to understand the local hydrological dynamics of a sacred forest, in terms of the benefits the village community derive, in central Western Ghats region of India. A comparative assessment has been made between two small watersheds in terms of their landscape structure (woody species composition) with soil water properties and availability of water in the respective downstream villages. The result shows that, sacred site with more primeval vegetation has close association with soil moisture in comparison to non-sacred site during dry spell of the year. The higher soil moisture ensures year long availability of water in the downstream village of the sacred site which facilitates farming of commercial crops with higher economic returns to the farmers, unlike the farmers in the other village where they face water crisis during the lean season. The study emphasizes the need for conservation endeavour on sacred groves highlighting its potential for water conservation at local and regional levels.