Driver training conditions affect sensitivity to the impairing effects of alcohol on a simulated driving test to the impairing effects of alcohol on a simulated driving test.

[Correction Notice: An erratum for this article was reported in Vol 16(2) of Experimental and Clinical Psychopharmacology (see record 2008-03846-009). The correct title of the article should read "Driver training conditions affect sensitivity to the impairing effects of alcohol on a simulated driving test".] Research shows that prior behavioral training in a challenging environment reduces alcohol-induced impairment on simple psychomotor tasks. However, no studies have examined if this relationship generalizes to driving performance. The present study examined simulated driving performance and tested the hypothesis that a challenging training history would protect against the impairing effects of alcohol on driving performance. The challenging training history involved driving in a visually-impoverished environment. Thirty adults were randomly assigned to one of three groups. Two groups were tested under alcohol (0.65 g/kg) after prior experience performing the task under either a visually-impoverished environment or a normal visual environment. The remaining group served as a control and was trained and tested under the visually-impoverished condition environment. Results showed that individuals trained in the impoverished environment displayed sober levels of performance when their performance was subsequently tested under alcohol. By contrast, volunteers trained in a normal environment showed impairment under alcohol. The findings suggest that differences in driving training history can affect a driver's sensitivity to the impairing effects of alcohol. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In situ synthesized ceramic–polymer composites for bone tissue engineering: bioactivity and degradation studies

As an alternative to current bone grafting strategies, a poly-lactide-co-glycolide/calcium phosphate composite microsphere-based scaffold has been synthesized by the direct formation of calcium phosphate within forming microspheres. It was hypothesized that the synthesis of low crystalline calcium phosphate within forming microspheres would provide a site-specific delivery of calcium ions to enhance calcium phosphate reprecipitation onto the scaffold. Both polymeric and composite scaffolds were incubated in simulated body fluid (SBF) for 8 weeks, during which time polymer molecular weight, scaffold mass, calcium ion concentration of SBF, pH of SBF, and calcium phosphate reprecipitation was monitored. Results showed a 20% decrease in polymeric scaffold molecular weight compared to 11–14% decrease for composite scaffolds over 8 weeks. Composite scaffold mass and SBF pH decreased for the first 2 weeks but began increasing after 2 weeks and continued to do so up to 8 weeks, suggesting interplay between pH changes and calcium phosphate dissolution/reprecipitation. Free calcium ion concentration of SBF containing composite scaffolds increased 20–40% over control values within 4 h of incubation but then dropped as low as 40% below control values, suggesting an initial burst release of calcium ions followed by a reprecipitation onto the scaffold surface. Scanning electron micrographs confirm calcium phosphate reprecipitation on the scaffold surface after only 3 days of incubation. Results suggest the composite scaffold is capable of initiating calcium phosphate reprecipitation which may aid in bone/implant integration.     

Daunorubicin‐Loaded DNA Origami Nanostructures Circumvent Drug‐Resistance Mechanisms in a Leukemia Model

Many cancers show primary or acquired drug resistance due to the overexpression of efflux pumps. A novel mechanism to circumvent this is to integrate drugs, such as anthracycline antibiotics, with nanoparticle delivery vehicles that can bypass intrinsic tumor drug‐resistance mechanisms. DNA nanoparticles serve as an efficient binding platform for intercalating drugs (e.g., anthracyclines doxorubicin and daunorubicin, which are widely used to treat acute leukemias) and enable precise structure design and chemical modifications, for example, for incorporating targeting capabilities. Here, DNA nanostructures are utilized to circumvent daunorubicin drug resistance at clinically relevant doses in a leukemia cell line model. The fabrication of a rod‐like DNA origami drug carrier is reported that can be controllably loaded with daunorubicin. It is further directly verified that nanostructure‐mediated daunorubicin delivery leads to increased drug entry and retention in cells relative to free daunorubicin at equal concentrations, which yields significantly enhanced drug efficacy. Our results indicate that DNA origami nanostructures can circumvent efflux‐pump‐mediated drug resistance in leukemia cells at clinically relevant drug concentrations and provide a robust DNA nanostructure design that could be implemented in a wide range of cellular applications due to its remarkably fast self‐assembly (≈5 min) and excellent stability in cell culture conditions.     

Inhibition of hIAPP Amyloid Aggregation and Pancreatic β‐Cell Toxicity by OH‐Terminated PAMAM Dendrimer

Human islet amyloid polypeptide (hIAPP, or amylin) forms amyloid deposits in the islets of Langerhans, a phenomenon that is associated with type‐2 diabetes impacting millions of people worldwide. Accordingly, strategies against hIAPP aggregation are essential for the prevention and eventual treatment of the disease. Here, it is shown that generation‐3 OH‐terminated poly(amidoamine) dendrimer, a polymeric nanoparticle, can effectively halt the aggregation of hIAPP and shut down hIAPP toxicity in pancreatic MIN6 and NIT‐1 cells as well as in mouse islets. This finding is supported by high‐throughput dynamic light scattering experiment and thioflavin T assay, where the rapid evolution of hIAPP nucleation and elongation processes is halted by the addition of the dendrimer up to 8 h. Discrete molecular dynamics simulations further reveal that hIAPP residues bound strongly with the dendrimer near the c‐terminal portion of the peptide, where the amyloidogenic sequence (residues 22–29) locates. Furthermore, simulations of hIAPP dimerization reveal that binding with the dendrimer significantly reduces formation of interpeptide contacts and hydrogen bonds, thereby prohibiting peptide self‐association and amyloidosis. This study points to a promising nanomedicinal strategy for combating type‐2 diabetes and may have broader implications for targeting neurological disorders whose distinct hallmark is also amyloid fibrillation.     

Do problematic and non-problematic video game players differ in extraversion,trait empathy,social capital and prosocial tendencies?

The increasing popularity of online and multiplayer games has meant that for many, social interaction and cooperation are vital components of the gaming experience. Previous research has suggested that not only has this made gaming more attractive to socially oriented people but also that it may be socially beneficial in terms of social capital and prosocial behaviors. However, for problematic video game players (those showing signs of compulsive or detrimental video game use), this may not be the case, and a number of theories hold deficiencies in socializing in real life as central to the development of this issue. In the present study, an online questionnaire completed by 416 participants assessed problematic video game use, extraversion, trait empathy, online and offline social capital and prosocial tendencies. Contrary to hypotheses, non-problematic, problematic and non-gamers did not differ in empathy, extraversion or prosocial tendencies. Problematic video game play was, however, associated with significantly higher online social capital and lower offline social capital whereas non-problematic players demonstrated only higher online capital than non-players. This highlights the importance of social support but suggests personality is not an influential factor.     

Emotional selection in memes: The case of urban legends.

This article explores how much memes like urban legends succeed on the basis of informational selection (i.e., truth or a moral lesson) and emotional selection (i.e., the ability to evoke emotions like anger, fear, or disgust). The article focuses on disgust because its elicitors have been precisely described. In Study 1, with controls for informational factors like truth, people were more willing to pass along stories that elicited stronger disgust. Study 2 randomly sampled legends and created versions that varied in disgust; people preferred to pass along versions that produced the highest level of disgust. Study 3 coded legends for specific story motifs that produce disgust (e.g., ingestion of a contaminated substance) and found that legends that contained more disgust motifs were distributed more widely on urban legend Web sites. The conclusion discusses implications of emotional selection for the social marketplace of ideas. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sharing the floodplain: Mediated modeling for environmental management

Complex ecosystems, such as the Upper Mississippi River (UMR), present major management challenges. Such systems often provide a range of ecosystem services that are differentially valued by stakeholders representing distinct interests (e.g., agriculture, conservation, navigation) or institutions (e.g., federal and state agencies). When no single entity has the knowledge or authority to resolve conflicts over shared resource use, stakeholders may struggle to jointly understand the scope of the problem and to reach reasonable compromises. This paper explores mediated modeling as a group consensus building process for understanding relationships between ecological, economic and cultural well-being in the UMR floodplain. We describe a workshop structure used to engage UMR stakeholders that may be extended to resource use conflicts in other complex ecosystems. We provide recommendations for improving on these participatory methods in structuring future efforts. In conclusion, we suggest that tools which facilitate collaborative learning, such as mediated modeling, need to be incorporated at an institutional level as a vital element of integrated ecosystem management.     

Effect of dopants on alumina grain boundary sliding: implications for creep inhibition

We investigate by means of periodic density functional theory the mechanism of grain boundary sliding along the α-alumina Σ11 tilt grain boundary. We identify minimum and maximum energy structures along a preferential sliding pathway for the pure grain boundary, as well as for grain boundaries doped with a series of early transition metals, as well as barium, gadolinium, and neodymium. We predict that the segregation of those dopants results in a considerable increase in the grain boundary sliding barrier. Grain boundary sliding occurs by a series of bond breaking and forming across the grain boundary. Our results suggest that the presence of large cations inhibits the regeneration of bonds during sliding, which results in a decrease in total number of bonds across the grain boundary interface, thereby raising the barrier to sliding. Trends in predicted grain boundary sliding energies are in good agreement with recently measured creep activation energies in polycrystalline alumina, lending further credence to the notion that grain boundary sliding plays a dominant role in alumina creep.     

Embedded cluster Δ-XANES modeling of adsorption processes on Pt

Full multiple scattering models of X-ray absorption near edge spectra of Pt Janin clusters, with atop and bridge bound oxygen, were systematically improved by increasing the number of cluster atoms contributing X-ray photoelectrons from unity (limited-absorber model), to all six Janin cluster Pt atoms, and finally embedding the Janin cluster into a larger Pt reservoir with photoelectron contributions from all atoms. The simulated XANES of the adsorbate modified clusters were subtractively normalized to their respective clean clusters to yield Δ-XANES signatures. The sequential analysis of previously published limited-absorber model, and the isolated and embedded all atoms models provide insights concerning the relative contribution of surface vs. subsurface atoms to adsorbate induced ligand effects and charge compensation provided by the bulk lattice. Limitations to the application of Δ-XANES signatures to interpretation of Δ-XANES data obtained from an air-breathing fuel cell are discussed.