Mesograde amnesia during the sleep onset transition: replication and electrophysiological correlates

The present study was designed to explore mechanisms of amnesia for meaningful auditory material presented during the sleep onset transition. Thirty undergraduate subjects (17 female, 13 male) were presented with auditory stimuli in an oddball paradigm until sleep onset. Subjects were allowed to accumulate either 30 seconds or 10 minutes of sleep, then awakened and tested on free recall and recognition memory for the meaningful stimuli. After 10 minutes of sleep, but not after 30 seconds of sleep, subjects had profound amnesia on free recall for stimuli presented in the 4-minute window prior to sleep onset. Increased beta electroencephalograph (EEG) power during the sleep period correlated positively with recall of stimuli in the 4-minute presleep window. Event-related potential recordings provided suggestive evidence that subjects continued to process the auditory stimuli to some extent during the sleep onset transition. When allowed to sleep for 10 minutes, subjects evidenced a mixed anterograde and retrograde amnesia for auditory stimuli presented in the 4-minute window prior to sleep onset. The results are discussed in terms of stimulus encoding, consolidation, and retrieval.     

Optic chiasm astrocytomas of childhood. 1. Long-term follow-up

There are many in vivo animal models for studying airway mucus secretion and hypersecretion, each with advantages and disadvantages. Use of a particular test system will depend upon the aspect of secretion to be modelled. Airway hypersecretory diseases exhibit chronic mucus hypersecretion, of which the clinical impact is predominantly in the distal airways. The majority of documented test preparations study acute secretion, invariably using tracheal preparations, but have been invaluable in elucidating the normal physiology of airway mucus secretion. Chronic models of the hypersecretory state in the distal airways have been developed, but are predominantly histologic in nature (for example quantification of increased goblet cell number). There are few investigations of mucus hypersecretion. Examination of the 'antisecretory' potential of pharmaceutical compounds has been investigated predominantly in chronic histologic models with the drug being given 'prophylactically' rather than 'therapeutically'. Refinement of chronic hypersecretory models should lead to elucidation of the connection between airway irritation, inflammation, MUC gene expression, mucous cell hyperplasia/metaplasia, airway hypersecretion and bronchial hypersecretory disease.     

Effect of object onset on the distribution of visual attention.

There now exists considerable evidence to suggest that the appearance of a new object in the visual field captures visual attention. One of the consequences of this attentional capture is that the object initiates a redistribution of attentional resources across visual space. This is classically observed in the precuing paradigm in which the onset of an abrupt cue influences the processing of a subsequently presented target. The present research describes a new phenomenon that occurs as a result of a new object appearing in the visual field. A stimulus presented in a region of space adjacent to a comer of an onsetting object receives an enhancement of processing relative to a stimulus presented adjacent to one of the object's straight edges. With the use of 2 converging methods, evidence is presented that suggests that the effect is a higher order attentional phenomenon whereby greater resources become directed to the comers of objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gravitational effects on grain coarsening during liquid-phase sintering

Grain growth in liquid-phase sintering (LPS) is often treated as an extension of Ostwald ripening. However, the inherent grain contact at high solid contents leads to coalescence and other conflicts with most coarsening theories. Consequently, grain growth rates during LPS significantly deviate from the predictions of most coarsening theories. This study compares grain sizes of tungsten heavy alloys sintered on Earth and under microgravity conditions. The microgravity samples consistently produced a smaller grain size. A case is made for a gravity contribution to coarsening during LPS. Such a concept provides a rationalization for previously reported differences in sintered grain size with location in compacts sintered on Earth.     

Cover Picture: Improving Organic Thin‐Film Transistor Performance through Solvent‐Vapor Annealing of Solution‐Processable Triethylsilylethynyl Anthradithiophene (Adv. Mater. 13/2006)

In work reported by Loo and co‐workers on p. 1721, the current–voltage characteristics of triethylsilylethynyl anthradithiophene (TES ADT) thin‐film transistors are improved dramatically by a simple solvent‐vapor annealing process after device fabrication. Exposing the transistors to dichloroethane vapor induces structural rearrangement and crystallization of TES ADT, as shown on the cover (lower section, before annealing, upper section, after). The annealing results in drastic increases in on currents; the saturation mobility increases by two orders of magnitude and the current–voltage hysteresis is largely eliminated.     

Relationships between young drivers' personality characteristics, risk perceptions, and driving behaviour

Research has shown that inexperienced drivers underestimate the risks associated with a range of driving situations. In addition, personality factors are an important influence on both risk perceptions and driving behaviour. The study investigated the strength of relationship between personality factors, risk perceptions, and driving behaviour among young, mainly inexperienced drivers. One-hundred and fifty-nine students aged between 17 and 20 completed an online questionnaire assessing five facets of personality, four components of risk perceptions, and one measure of driving behaviour. Using structural equation modeling as a means of assessing the overall fit of each model, 39% of the variance in young drivers' speeding was accounted for by Excitement-Seeking, Altruism, their Aversion to Risk Taking, and their own likelihood of having an accident, with Altruism and Aversion to Risk Taking both showing moderate negative relationships. Road safety interventions should examine whether they strengthen young drivers' appreciation of the impact of their actions on others through positive reinforcement of altruistic norms.     

Rapid melting curve analysis on monolayered beads for high-throughput genotyping of single-nucleotide polymorphisms

This report describes a rapid solid-phase melting curve analysis method for single-nucleotide polymorphism (SNP) genotyping. The melting curve analysis is based on dynamic allele-specific hybridization (DASH). The DNA duplexes are conjugated on beads that are immobilized on the surface of a microheater chip with integrated heaters and temperature sensors. SNP on PCR products were scored, illustrating the sensitivity and robustness of the system. The method is based on random bead immobilization by microcontact printing. Single-bead detection and multiplexing were performed with a heating rate more than 20 times faster than conventional DASH. Analyses that took more than 15 min could be performed in less that 1 min, enabling ultrarapid SNP analysis. In addition, an array version of the chip was implemented enabling the preparation of an array of bead arrays for high-throughput and rapid SNP genotyping.     

Spatio-temporal operator formalism for holographic recording and diffraction in a photorefractive-based true-time-delay phased-array processor

We present a spatio-temporal operator formalism and beam propagation simulations that describe the broadband efficient adaptive method for a true-time-delay array processing (BEAMTAP) algorithm for an optical beamformer by use of a photorefractive crystal. The optical system consists of a tapped-delay line implemented with an acoustooptic Bragg cell, an accumulating scrolling time-delay detector achieved with a traveling-fringes detector, and a photorefractive crystal to store the adaptive spatio-temporal weights as volume holographic gratings. In this analysis, linear shift-invariant integral operators are used to describe the propagation, interference, grating accumulation, and volume holographic diffraction of the spatio-temporally modulated optical fields in the system to compute the adaptive array processing operation. In addition, it is shown that the random fluctuation in time and phase delays of the optically modulated and transmitted array signals produced by fiber perturbations (temperature fluctuations, vibrations, or bending) are dynamically compensated for through the process of holographic wavefront reconstruction as a byproduct of the adaptive beam-forming and jammer-excision operation. The complexity of the cascaded spatial-temporal integrals describing the holographic formation, and subsequent readout processes, is shown to collapse to a simple imaging condition through standard operator manipulation. We also present spatio-temporal beam propagation simulation results as an illustrative demonstration of our analysis and the operation of a BEAMTAP beamformer.     

An energy conservation approach to adsorbate-induced surface stress and the extraction of binding energy using nanomechanics

Surface stress induced by molecular adsorption in three different binding processes has been studied experimentally using a microcantilever sensor. A comprehensive free-energy analysis based on an energy conservation approach is proposed to explain the experimental observations. We show that when guest molecules bind to atoms/molecules on a microcantilever surface, the released binding energy is retained in the host surface, leading to a metastable state where the excess energy on the surface is manifested as an increase in surface stress leading to the bending of the microcantilever. The released binding energy appears to be almost exclusively channeled to the surface energy, and energy distribution to other channels, including heat, appears to be inactive for this micromechanical system. When this excess surface energy is released, the microcantilever relaxes back to the original state, and the relaxation time depends on the particular binding process involved. Such vapor phase experiments were conducted for three binding processes: physisorption, hydrogen bonding, and chemisorption. Binding energies for these three processes were also estimated.