Computational proteomics on the grid

The large number of protein sequences, provided by genomic projects at an increasing pace, constitutes a challenge for large scale computational studies of protein structure and thermodynamics. Grid technology is very suitable to face this challenge, since it provides a way to access the resources needed in compute and data intensive applications. In this work, we concentrate on the grid-aware implementation of a protein structure prediction algorithm.     

Hemisphericity, cognitive set, and susceptibility to subliminal perception.

Although many studies have apparently demonstrated that subliminal stimuli influence perception and cognition, the effects have been weak and unreliable. A review of the factors related to the magnitude of these phenomena suggests that both individual differences in hemisphericity and situational manipulations of cognitive sets are associated with the strength of subliminal effects. This hypothesis was tested in a group of 24 right movers and 25 left movers (male undergraduates), who responded to subliminal stimuli under both organized and unorganized cognitive set conditions. Results indicate that left movers showed a subliminal effect in the unorganized condition, while they showed no effect in the organized condition. Right movers showed a reverse pattern. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Seismic analysis and design of electrical cable trays and support systems

Most cable trays in nuclear power plants are classified as seismic category I components. Current safety requirements dictate that all such components be adequately designed in order to remain functional during and after the most severe possible earthquake, so that a safe and orderly plant shut-down can be ensured. The design aspects of electrical cable trays and support systems are discussed from the seismic and structural standpoint. The effects of the inherent flexibility of commonly used cable trays is considered. A procedure for the selection of trays and the design of their support structure is recommended. The dynamic characteristics of typical trays are determined analytically and also from test results. The advantages of a rigid support system are discussed. Two procedures are presented for the design of the support systems, namely, static loading and spectral analysis. The interaction between trays and supports is discussed.     

Polyethyleneglycol catalytic dehydration kinetics in the liquid phase

Eleven representative polyethyleneglycol (25322–68–3) catalytic dehydration reactions have been studied in the liquid phase at atmospheric pressure. The aim of this research is to build a kinetic model representative of the polyethyleneglycol dehydration process. Three types of reaction take place simultaneously in the process: cyclisation, condensation and alcoholysis. Activation energies and frequency factors are given, and the relationships between kinetic parameters and chain length of reactants and products are discussed according to the reaction type.     

Interface tracking with dynamically-redistributed surface markers in unstructured quadrangular grids

In this work we present an extension of a front-tracking algorithm with a dynamical redistribution of surface markers for interface advection of a fluid body in unstructured quadrangular grids. The interface is described by an ordered list of markers connected by segments which are first advected along the streamlines and then redistributed uniformly along the interface while conserving the spanned area. In this article we perform two-dimensional tests over unstructured meshes and compare the results with those obtained in Cartesian grids. Solid body motions, such as translations and rotations, and more complex vortical flows which progressively deform and stretch the interface line are considered over different geometries. The results show that the interface evolution can be tracked successfully in challenging situations with a very good accuracy in terms of area conservation and a rather moderate decrease in the performance of the method with respect to the structured Cartesian mesh.     

Three-dimensional shape optimization of hip prostheses using a multicriteria formulation

A multicriteria optimization model is developed to obtain the optimal geometry of the femoral component of a hip prosthesis. The objective function minimizes both the relative tangential displacement and the contact normal stress. For cementless stems, these two factors are relevant for the prosthesis stability and therefore for the implant success. The three-dimensional optimization procedure developed allows us to characterize the stem shape that minimizes displacement and stress individually, or simultaneously using a multicriteria approach. Design variables characterize successive stem sections, and are subjected to linear geometric constraints to obtain clinically admissible geometries. Multiple loads are considered to incorporate several daily life activities. The system bone–stem is considered a structure in equilibrium with contact condition on the interface. Results show that thin stem tips minimize the interface stress while collared stems minimize displacement. The multicriteria formulation leads to balanced solutions.     

Metal Particle Composite Hardening in Ba0.85Ca0.15Ti0.90Zr0.10O3 Piezoceramics

Hard-type piezoceramics are key materials in high-power transducers and transformers. Acceptor doping is the most widely used piezoelectric hardening approach, but the mobility of oxygen vacancies at large electric fields or at high temperatures inevitably leads to the deterioration of hardening performance. The present study proposes a new hardening method associated with intragranular metal particles for achieving strong pinning of ferroelectric domain walls. Highly effective piezoelectric hardening via intragranular Ag particles in Ba_0.85Ca_0.15Ti_0.90Zr_0.10O₃ ceramic is realized, where the mechanical quality factor Q_m and the coercive field E_c increase by 170% and 53%, respectively. The Ba_0.85Ca_0.15Ti_0.90Zr_0.10O₃/0.10Ag sample features a larger high-power mechanical quality factor than the pure Ba_0.85Ca_0.15Ti_0.90Zr_0.10O₃. Moreover, the piezoelectric properties (d₃₁ and k₃₁) of the Ba_0.85Ca_0.15Ti_0.90Zr_0.10O₃/0.10Ag sample show exceptional stability with the increase in vibration velocity. This composite approach of introducing metal particles can be considered as a generic hardening method and can be extended to other ferroelectric systems.     

Thiophene-Based Optical Ligands That Selectively Detect Aβ Pathology in Alzheimer's Disease

In several neurodegenerative diseases, the presence of aggregates of specific proteins in the brain is a significant pathological hallmark; thus, developing ligands able to bind to the aggregated proteins is essential for any effort related to imaging and therapeutics. Here we report the synthesis of thiophene-based ligands containing nitrogen heterocycles. The ligands selectively recognized amyloid-β (Aβ) aggregates in brain tissue from individuals diagnosed neuropathologically as having Alzheimer's disease (AD). The selectivity for Aβ was dependent on the position of nitrogen in the heterocyclic compounds, and the ability to bind Aβ was shown to be reduced when introducing anionic substituents on the thiophene backbone. Our findings provide the structural and functional basis for the development of ligands that can differentiate between aggregated proteinaceous species comprised of distinct proteins. These ligands might also be powerful tools for studying the pathogenesis of Aβ aggregation and for designing molecules for imaging of Aβ pathology.