Experimental Investigations on Microstructure,Mechanical Behavior and Tribological analysis of AA5154/SiC Composites by Stir Casting

Silicon - Aluminum metal matrix composites (MMCs) exhibit promising mechanical properties that are potential materials for the aeronautical and automotive industries. In this study,...     

Lamotrigine‐loaded polyacrylate nanoparticles synthesized through emulsion polymerization

A series of copolymeric nanoparticles of the partially water‐soluble monomer ethyl methacrylate and the water‐soluble monomer 2‐hydroxyl ethyl methacrylate were synthesized from emulsions containing sodium dodecyl sulfate via free‐radical polymerization. Lamotrigine, as a model drug, was loaded in nanoparticles during in situ polymerization. A stable and transparent poly(ethyl methacrylate‐co‐hydroxyl ethyl methacrylate) nanolatex was produced for all compositions and characterized for particle size by dynamic light scattering and transmission electron microscopy. Particles were found to be smaller than 50 nm in size. Structural characterization of copolymers was done by infrared spectrometry, gel permeation chromatography, and NMR spectroscopy. Drug encapsulation efficiency was determined by ultraviolet (UV)–visible spectrometry and was found to be 26–62% for copolymers with different compositions. UV data suggest molecular‐level dispersion of the drug in the nanoparticles. In vitro drug‐release studies showed the controlled release of lamotrigine. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Challenges in nucleic acid‐lipid films for transfection

The use of surface‐based methods for the delivery of therapeutics has recently generated increasing interest. These platforms have tremendous potential to minimize detrimental side effects associated with systemic delivery by localizing the therapeutic vehicle, and thus provide higher local doses for improved efficacy. Cationic lipids are one of the most commonly used synthetic carriers for the delivery of genetic cargo, such as DNA and RNA. However, reports on the use of lipid‐based films for gene delivery are scarce. Here we investigate the use of a lipid‐based film for the in vitro delivery of plasmid DNA. Solid DNA‐lipid films show very low levels of transfection, while identical complexes prepared for bolus delivery provide high levels of transfection when used directly. We investigate the mechanism, whereby the activity of these solid‐state films is lost and suggest methods for circumventing these challenges and restoring the efficacy of these films as gene delivery platforms. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3203–3213, 2013     

Characterization of Competitive Inhibitors of Plasmodium falciparum cGMP-Dependent Protein Kinase**

Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) is an enticing antimalarial drug target. Novel chemotypes are needed because existing inhibitors have safety issues that may prevent further development. This work demonstrates isoxazole-based compounds are potent ATP competitive inhibitors of PfPKG and discloses a new analogue in this series. Isoxazoles 3 and 5 had K_i values that are comparable to a known standard, 4-[2-(4-fluorophenyl)-5-(1-methylpiperidine-4-yl)-1H pyrrol-3-yl] pyridine. They also exhibited excellent selectivity for PfPKG over the human orthologue and the gatekeeper mutant T618Q PfPKG, which mimics the less accessible binding site of the human orthologue. The human orthologue's larger binding site volume is predicted to explain the selectivity of the inhibitors for the P. falciparum enzyme.     

Effect of accelerated aging on the tensile index of a synthetic insulation paper

This paper explores the possibility of using tensile index as one of the appropriate end point parameters to determine the thermal index of a synthetic insulation paper. The paper samples were aged at three different times and temperatures. The tensile index of fresh as well as aged samples was determined experimentally. The study showed that tensile index could be considered as an appropriate parameter to find the thermal index of the chosen synthetic insulation paper.     

Morphology,thermomechanical properties,and biodegradability of low density polyethylene/starch blends

The biodegradability of low density polyethylene (LDPE)/starch and LDPE/starch/starch acetate (STAc) blends was tested and observed to be dependent on STAc content. The binary and ternary blends containing up to a maximum concentration of 30% starch were examined for their thermal, mechanical, and morphological properties. The blends with no STAc or 2.5% STAc show almost no adherence of two phases. With 10% STAc, dispersion of starch was observed to increase with some adherence to LDPE. Tensile strength, elongation at break, and Izod impact strength of the blends decreased with increased starch content. However, incorporation of STAc along with starch improved all these properties, particularly elongation at break and toughness. The melt flow index was also improved on partial substitution of starch by STAc. Maximum biodegradability was observed for the blends containing 30% (starch + STAc). Cell growth was observed to increase with increasing concentration of (starch + STAc) in the blends. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2791–2802, 1999     

Prioritizing towards a green export portfolio for India: An environmental input–output approach

Proponents of free trade have often hailed international trade as an engine of economic growth. However, the foreign trade sector, like many other sectors in developing countries, frequently involves these countries walking a tightrope between their developmental objectives and environmental goals. In this regard, prioritizing for developing a ‘green’ yet internationally competitive export portfolio provides a quintessential win–win solution to the problem. This study factors in both environmental benignity (indicated by total CO₂ emission intensity) as well as trade competitiveness (indicated by revealed comparative advantage index) in identifying the ‘ideal’ Indian export portfolio. The analysis calculates the level of direct and indirect emissions from the foreign trade sector (exports and imports) using the environmental input–output (EIO) matrix for 2003/04 for India that has been jointly developed by researchers from Keio University, Japan, and The Energy and Resources Institute (TERI), New Delhi. The derived basket is compared to the current portfolio to estimate the potential saving from compositional changes and to suggest directions for policymaking to emphasize or de-emphasize the export of certain categories of exports.     

Solution properties of methyl methacrylate–acrylonitrile copolymers

Characterization of methyl methacrylate-acrylonitrile copolymers is done through viscosity, swelling, and differential refractometric studies. Viscosities of the copolymers and homopolymers were determined at 30, 40, and 50°C. The activation parameters of viscous flow, voluminosity, and shape factor were also calculated. The average shape factor was observed to be 2.5 ± 0.005 for all copolymer systems. Viscosity molecular weights were calculated, and from intramolecular expansion factor (α), it was observed that copolymers are less flexible than are homopolymers. dn/dc values obtained from differential refractometry are in good agreement with those calculated theoretically. © 1993 John Wiley & Sons, Inc.     

Relationship between morphology and mechanical properties of binary and compatibilized ternary blends of polypropylene and nylon 6

The effect of compatibilization on the morphology, mechanical properties, and dynamic mechanical properties of isotactic polypropylene (IPP)/nylon-6 (Ny-6) binary blends was investigated. Maleic anhydride (MAH) functionalized IPP was used as a compatibilizer in binary blends. The morphological, mechanical, and dynamic mechanical properties of binary and ternary blends were compared. The blends containing IPP-g-MAH showed more regular and finer dispersion of phases, different dynamic properties, and improved mechanical properties due to better adhesion between the two phases. The blends were also characterized for their flow properties and extent of water absorption. The melting peak temperature and percent crystallinity of IPP and Ny-6 phases were decreased in compatibilized blends. © 1996 John Wiley & Sons, Inc.     

Microstructural characterization and corrosion behavior of multipass friction stir processed AA2219 aluminium alloy

Multipass friction stir processing of AA 2219-T87 aluminium alloy to a depth of 2 mm in a 5 mm plate resulted in fine α-Al grains, reduction and dissolution of both eutectic phase (CuAl₂) and the strengthening precipitates (CuAl₂). Anodic polarization and electrochemical impedance tests in 3.5% NaCl showed an improved corrosion resistance of the processed alloy, which increased with the number of passes. Salt spray and immersion tests also showed improved resistance to corrosion. The increased resistance to corrosion is attributed to the dissolution of CuAl₂ particles, which was established by XRD and DSC studies.