Profile of cognitive functioning in women with the fragile X mutation.

Two studies tested the specificity of the neurocognitive profile of women with fragile X syndrome (FXS). First, women with an FXS full mutation were compared with women with a premutation and women without FXS who grew up in FXS families. Women with FXS had a significantly lower IQ than the other groups, and analyses of subtest profiles showed they had a relative weakness on Arithmetic and strength on Picture Completion. Women with FXS performed worse than the other groups on executive function, spatial ability, and visual memory. Next, women with FXS were compared with women without FXS matched on age and IQ. A similar IQ profile was found, but women with FXS were worse than controls only on executive function. The authors also examined which neurocognitive indices were related to the underlying biology of the disorder. Overall, the results indicated that executive rather than visuospatial deficits were primary in the neurocognitive profile of FXS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reversible active switching of the mechanical properties of a peptide film at a fluid-fluid interface

Designer peptides have recently been developed as building blocks for novel self-assembled materials with stimuli-responsive properties. To date, such materials have been based on self-assembly in bulk aqueous solution or at solid-fluid interfaces. We have designed a 21-residue peptide, AM1, as a stimuli-responsive surfactant that switches molecular architectures at a fluid-fluid interface in response to changes in bulk aqueous solution composition. In the presence of divalent zinc at neutral pH, the peptide forms a mechanically strong 'film state'. In the absence of metal ions or at acid pH, the peptide adsorbs to form a mobile 'detergent state'. The two interfacial states can be actively and reversibly switched. Switching between the two states by a change in pH or the addition of a chelating agent leads to rapid emulsion coalescence or foam collapse. This work introduces a new class of surfactants that offer an environmentally friendly approach to control the stability of interfaces in foams, emulsions and fluid-fluid interfaces more generally.     

Uptake and biocompatibility of functionalized poly(vinylalcohol) coated superparamagnetic maghemite nanoparticles by synoviocytes in vitro

Superparamagnetic iron oxide nanoparticles (SPION) were coated with either Polyvinyl alcohol (PVA) or Vinyl alcohol/vinyl amine copolymer and further functionalized with the fluorochromes Cy3.5 or Texas Red. A colloidally stable suspension of nanoparticles was incubated on sheep synovial cells in vitro for 3, 24, 72, and 120 hours. Nanoparticle internalization into synoviocytes as well as biocompatibility was visualized using light, fluorescence and confocal microscopy and fluorochrome labeled cells were quantified by flow cytometry. Data were analyzed by ANOVA factorial tests. Amino-PVA-SPION alone was detectable in cytoplasmic endosome-like structures after 3 hours of incubation but resulted in early cell death after 24 hours. Although amino-PVA-Cy3.5-SPION and PVA-TexasRed-SPION were taken up more slowly and less intensely, both labeled more than 80% of the cells in culture, but did not significantly change cell morphology or vitality at any time of evaluation in comparison to control cells. Results indicate that functionalized amino PVA-coated SPION are biocompatible, were successfully internalized by synoviocytes and hold promise for future biomedical applications utilizing magnetic drug targeting in joint disease.     

Understanding affect in design: an outline conceptual framework

This paper provides an outline conceptual framework that may be helpful for those involved in the emerging area of ‘affective design’. Historically, the shift from cognitive approaches that eschewed emotions towards a more encompassing conceptual approach that includes affective or emotive processes is understandable. A basic understanding of concepts such as affect and emotion are required in order to address many questions such as how to design to evoke affect and how to predict user emotions? We utilize concepts from Activity Theory in order to understand the world of ‘feelings’. The latter involves several different levels and classes, principally those of affect, emotion and sentiment. Feelings involve important psychological processes, although they have received minimal attention within the mainstream cognitive frame until very recently. The intent of this paper is to provide a coherent conceptual frame for the discussions within the interaction design and HCI communities concerning such terms as emotional interfaces, hedonic design and affective design.     

Mixing Enhancement in Gas-Stirred Melts by Rotating Magnetic Fields

A model experiment of a submerged gas injection system in a cylindrical vessel under the influence of a rotating magnetic field and its effect on liquid metal mixing is presented. Argon gas is injected through a nozzle into a column of the eutectic alloy GaInSn, which is liquid at room temperature. Without a magnetic field, the bubble plume in the center region of the cylindrical vessel produces a recirculation zone with high fluid velocities near the free surface, while the fluid velocities in the bottom region are rather low. Our measurements revealed the potential of rotating magnetic fields to control both the amplitude of the meridional flow and the bubble distribution and to provide an effective mixing in the whole fluid volume. Various periodic flow patterns were observed in a certain parameter range with respect to variations of the magnetic field strength and the gas flow rate.     

Hydroaminomethylation of n‐Alkenes in a Biphasic Ionic Liquid System

Hydroaminomethylation reactions were performed successfully in an imidazolium‐based ionic liquid using a rhodium/sulfoxantphos system by reacting piperidine with different n‐alkenes, affording yields higher than 95 % of the resulting amine with turnover frequencies of up to 16,000 h⁻¹, along with high regioselectivity for the linear amines with l/b ratios up to 78. Additionally, facile quantitative catalyst recovery was accomplished and recycling of the catalyst and product separation was achieved by a fast phase separation after the reaction. The product distribution was monitored over time at different temperatures both in an organic solvent and in the ionic liquid in order to investigate and compare the course of the formation of (side) products and intermediates in these reactions. Furthermore, it was shown that the nature of the rhodium precatalyst has a profound effect on the activity and selectivity. Protic organic solvents and ionic liquids containing a C H acidic bond in the imidazolium part have a beneficial effect on the hydrogenation activity of the catalyst systems.     

Mobility-limiting mechanisms in polar semiconductor heterostructures

The mechanisms controlling the carrier mobility of two-dimensional electron gases (2DEGs) in ultrathin polar semiconductor heterostructures, such as III–V nitrides, have been analyzed. In_xAl_1?xN/AlN/GaN heterostructures with different AlN layer thicknesses have been investigated. These structures can be considered a very good benchmark for the analyses of III–V nitrides, due to the possibility of modulating the strain by varying the In composition. In order to determine an estimate of the mobility, charged dislocation and remote surface roughness scattering lifetimes have been calculated. Atomic force microscopy and scanning tunneling microscopy analyses have been used to measure the parameters required for the lifetime calculation, such as surface roughness, correlation length and dislocation density, and the total mobility has thus been calculated without the need of any a priori assumptions on the values of these parameters. The mobility of In_xAl_1?xN/AlN/GaN heterostructures has been measured at room temperature and liquid nitrogen temperature by the Hall effect. A comparison between the calculated and the Hall-effect-measured mobilities allowed us to establish, without using any ad hoc assumptions or fitting parameters, that the remote surface roughness is the most effective factor in controlling the transport properties of 2DEGs in nitride-based heterostructures at low temperature.     

Reconstruction procedure for 3D micro X-ray absorption fine structure

A new approach for chemical speciation in stratified systems using 3D Micro-XAFS spectroscopy is developed by combining 3D Micro X-ray Fluorescence Spectroscopy (3D Micro-XRF) and conventional X-ray Absorption Fine Structure Spectroscopy (XAFS). A prominent field of application is stratified materials within which depth-resolved chemical speciation is required. Measurements are collected in fluorescence mode which in general lead to distorted spectra due to absorption effects. Developing a reliable reconstruction algorithm for obtaining undistorted spectra for superficial and in-depth layers is proposed and validated. The developed algorithm calculates the attenuation coefficients of the analyte for the successive layers facilitating a new spectroscopic tool for three-dimensionally resolved nondestructive chemical speciation.     

Development and characterization of a coronary polylactic acid stent prototype generated by selective laser melting

In-stent restenosis is still an important issue and stent thrombosis is an unresolved risk after coronary intervention. Biodegradable stents would provide initial scaffolding of the stenosed segment and disappear subsequently. The additive manufacturing technology Selective Laser Melting (SLM) enables rapid, parallel, and raw material saving generation of complex 3- dimensional structures with extensive geometric freedom and is currently in use in orthopedic or dental applications. Here, SLM process parameters were adapted for poly-l-lactid acid (PLLA) and PLLA-co-poly-ε-caprolactone (PCL) powders to generate degradable coronary stent prototypes. Biocompatibility of both polymers was evidenced by assessment of cell morphology and of metabolic and adhesive activity at direct and indirect contact with human coronary artery smooth muscle cells, umbilical vein endothelial cells, and endothelial progenitor cells. γ-sterilization was demonstrated to guarantee safety of SLM-processed parts. From PLLA and PCL, stent prototypes were successfully generated and post-processing by spray- and dip-coating proved to thoroughly smoothen stent surfaces. In conclusion, for the first time, biodegradable polymers and the SLM technique were combined for the manufacturing of customized biodegradable coronary artery stent prototypes. SLM is advocated for the development of biodegradable coronary PLLA and PCL stents, potentially optimized for future bifurcation applications.