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Huntington's disease (HD) is an autosomal dominant disease affecting neurons predominantly in the striatum due to the production of the toxic huntingtin protein. Lowering the concentration of mutant huntingtin is a promising therapeutic approach, and a suitable delivery system is fascinating. Nanoparticles (NPs) minimize the host immune response and have no limit concerning the number of NPs administered. They are safe, targeted, and effective for RNA therapeutics providing a significant mode to cross the blood–brain barrier for a broad range of clinical applications. The present study generated and characterized magnetic NPs (MNPs) using the co-precipitation method with a mean particle size of around 10–20 nm. The dynamic light scattering and zeta potential measurements showed that NPs exhibited narrow size distribution and sufficient colloidal stability. These oleic acid-coated MNPs were further cross-linked with polyethyleneimine and designed to deliver interfering RNA into human embryonic kidney cells (HEK-293) driven by an external magnetic field. These MNPs showed low cytotoxicity with high transfection efficiency. Furthermore, a transient downregulation was observed in endogenous huntingtin protein obtained by RT-PCR and Western blot analysis. Thus, these MNPs may represent a promising and efficient platform for siRNA delivery and provide a potential treatment strategy for HD. [ABSTRACT FROM AUTHOR]

High-density polyethylene (HDPE) was blended with 'reinforcing' cycloolefin copolymer (COC) in order to produce polyolefin materials with increased stiffness, yield and tensile strength. Experimental data on tensile modulus [E.sub.b], creep modulus [E.sub.bcr], storage modulus [E.sub.b]', loss modulus [E'.sub.b], yield strength [S.sub.yb], and tensile strength [S.sub.ub] of blends are in plausible accord with their simultaneous prediction based on a predictive format that operates with a two-parameter equivalent box model and the data on the phase continuity of components obtained from modified equations of the percolation theory. Dependencies of these mechanical properties on blend composition indicate the critical volume fraction [v.sub.2cr] = 0.16 of COC. Interfacial adhesion in the HDPE/COC blends is strong enough to transmit acting stress up to the break point. Strain at break, tensile energy to break and tensile impact strength show conspicuous drops in the interval 15-25% of COC in the blends, during which COC starts to form a co-continuous brittle component. Further growth of COC fraction accounts for reduction of blend ultimate properties to values typical of brittle polymers. However, tensile impact strength shows a local maximum at HDPE/COC = 25/75, which probably corresponds to COC toughened with HDPE particles. POLYM. ENG. SCI., 45:817-826, 2005. © 2005 Society of Plastics Engineers, INTRODUCTION Polyethylene (PE) shows a relatively low yield strength and a high propensity to creeping. These deficiencies can be alleviated by blending PE with a yield- and/or creep-resistant polymer, which [...]

A cycloolefin copolymer matrix was melt mixed with exfoliated graphite nanoplatelets (xGnP) and the resulting nanocomposites were foamed by supercritical carbon dioxide. The density of the obtained foams decreased with the foaming pressure. Moreover, xGnP limited the cell growth during the expansion process thus reducing the cell diameter (from 1.08 to 0.22 mm with an XGnP amount of 10 wt% at 150 bar) and increasing the cell density (from 12 to 45 cells/mm² with a nanofiller content of 10 wt% at 150 bar). Electron microscopy observations of foams evidenced exfoliation and orientation of the nanoplatelets along the cell walls. Quasi-static compressive tests and tensile creep tests on foams clearly indicated that xGnP improved the modulus (up to a factor of 10 for a xGnP content of 10 wt%) and the creep stability. [ABSTRACT FROM AUTHOR]

Nanomer and Cloisite are the popular commercial nanoclays (NC) available in the market. The mechanical properties of wood—plastic composite (WPC) based on linear low density polyethylene with or without wood fiber are compared for different added nanoclays. In addition, the moisture uptakes at 23°C and 45% RH and water uptake/loss after immersion in water are evaluated. I.34TCN type nanoclay as well as Cloisite Na+ lead to composites with superior mechanical properties and better water resistance behaviors compared to the other kinds of nanoclays. It should be noted that the discoloration occurs in WPC reinforced with unmodified NC. [ABSTRACT FROM AUTHOR]