Search

Enhanced diffusion in high angle grain boundaries in Al 2 O 3 is usually attributed to relatively easy point defect jumping in the plane of the boundary, due to the more open and disordered geometry of random boundaries. However, the pre-exponentials revealed by recent diffusion experiments are incompatible with a point defect mechanism. Instead, such grain boundary diffusion is thought to occur by migration of disconnections, grain boundary ledge defects characterized by a step height h , and a Burgers vector, b . [ABSTRACT FROM AUTHOR]

This cross-sectional study was designed to assess the predictors of coping behaviors of 147 Lebanese parents (101 mothers and 46 fathers) with a child with intellectual disability. It assessed the contribution of child's and parent's characteristics, informal social support, and stress on the coping behaviors of fathers and mothers. Multiple regression analysis confirmed that the father's education, informal social support, and stress were the best predictors of coping. The child's age, severity of illness, and parental health did not significantly contribute to predicting coping behaviors. Contrary to expectations in a Middle Eastern culture, both fathers and mothers reported similar levels of stress, perceived informal social support, and coping. Although informal social support cannot be forced on parents, health professionals can mobilize resources that are culturally sensitive, such as home visitation by nurses or support from other parents. This may especially be beneficial in developing countries with limited resources.Copyright © 2010 by Elsevier Inc. [ABSTRACT FROM AUTHOR]

Abstract: The effect of forming method (cold isostatic pressing and slip casting) on particle packing and the consequent effects on densification, phase transformation and microstructural evolution were evaluated during sintering of a transition alumina powder (Nanotek®, particle size of 47nm, δ and γ phases). It is well known that the transformation of transition alumina towards the stable α phase has a critical influence on the sintering behaviour. Therefore, correlation between microstructural evolution and shrinkage in compacts was established using dilatometry, Scanning Electron Microscopy and X-Ray Diffraction. By the two mentioned forming methods, green bodies with the same density were processed, in order to investigate only particle packing homogeneity and its effect on phase transition and sintering. For the same initial green density, the samples prepared by slip casting present a better homogeneity of particle packing, due to an optimal dispersion of particles in the slurry. This initial microstructure feature improves the particles rearrangement during the transition to α-alumina and hence enhances the transformation to the thermodynamic stable α-phase and the densification step. [Copyright &y& Elsevier]

A novel second generation retroviral producer cell strategy (an adenoviral/retroviral combined delivery system) has been developed by this laboratory. In the present studies, this delivery system was used to examine its delivery efficiency in vitro and in vivo by using a marker gene, LacZ, and a therapeutic gene, herpes simplex virus thymidine kinase (HSV-tk), both of which were transduced into a tumor cell line KBALB. In the in vitro experiments for delivery efficacy of the LacZ gene, the delivery efficiency of KBALB+KBALBLNPOZAdN/H (1:1) was 27.8% higher than that of KBALB+KBALBLNPOZ (1:1) (P<0.01). For the antitumor effect of HSV-tk/ganciclovir (GCV), the death ratio of KBALB+KBALBLNCTKAdN/H (1:1) was higher than that of KBALB+KBALBLNCTK (1:1), on 4, 6, and 8 days at a concentration of 0.1, 1, and 10 μg/ml, respectively (P<0.01 or P<0.05). In the in vivo experiments for LacZ gene expression, the delivery efficiency in KBALB+KBALBLNPOZAdN/H (1:1) was 21.5% more efficient than that in KBALB+KBALBLNPOZ (1:1) (P<0.01). For HSV-tk/GCV antitumor effect, the suppression of tumors by KBALB+KBALBLNCTKAdN/H (1:1) was more effective than that by KBALB+KBALBLNCTK (1:1) (P<0.05). Results suggest that this new delivery system is more efficient than the traditional in vitro and in vivo retroviral vector delivery system. [Copyright &y& Elsevier]

Memristors with steep off-on transitions and high “on” currents are excellent candidates for very low power and efficient electronics. Owing to their switching mechanism based on ion motion and oxidation/reduction process, memristors bridge the gap between MEMS and MOSFETs. They have better reliability similar to MOSFETS and at the same time have the more desirable off-to-on current ratios of MEMS. Here we show that by adding a gate electrode to memristors, the SET/RESET voltages in electrochemical memristors can be controlled enabling their applications in circuits with high input/output isolations. We discuss devices with 2 mV/dec sub-threshold slope and show that the gate field effect can be used to modify the SET/RESET voltages considerably. In addition to enabling very low power switches using memristors, the gate can also be used as a global RESET. [ABSTRACT FROM AUTHOR]