Electric potential mapping by thickness variation: A new method for model-free mobility determination in organic semiconductor thin films

Charge transport, with charge carrier mobility as main parameter, is one of the fundamental properties of semiconductors. In disordered systems like most organic semiconductors, the effective mobility is a function of the electric field, the charge carrier density, and temperature. Transport is often investigated in a space-charge limited current (SCLC) regime in thin film single carrier devices, where an electric current is driven in the direction perpendicular to the surface. Direct evaluation of the current–voltage characteristics, however, is problematic, because parasitic contributions from injection or extraction barriers can falsify results.     

Symmetric Large‐Area Metal‐Molecular Monolayer‐Metal Junctions by Wedging Transfer

A method is described for fabricating and electrically characterizing large‐area (100–400 μm²) metal‐molecular monolayer‐metal junctions with a relatively high overall yield of ≈45%. The measurement geometry consists of ultra‐smooth (template‐stripped) patterned Au bottom electrodes, combined with ultra‐smooth top Au electrodes deposited using wedging transfer. The fabrication method is applied to the electrical characterization of Au‐alkanethiol self‐assembled monolayer‐Au junctions. An exponential decay of the current density is found for increasing the chain length of the alkanethiols, in agreement with earlier studies. The symmetric device geometry, and flexibility for contacting monolayers with various end groups are important advantages compared to existing techniques for electrically characterizing molecular monolayers.     

Protein kinase Mzeta maintains fear memory in the amygdala but not in the hippocampus.

Recent work on the long-term stability of memory and synaptic plasticity has identified a potentially critical role for protein kinase Mzeta (PKMζ). PKMζ is a constitutively active, atypical isoform of protein kinase C that is believed to maintain long term potentiation at hippocampal synapses in vitro. In behaving animals, local inhibition of PKMζ disrupts spatial memory in the hippocampus and conditioned taste aversion memory in the insular cortex. The role of PKMζ in context fear memory is less clear. This study examined the role of PKMζ in amygdala and hippocampal neurons following a standard fear conditioning protocol. The results indicate that PKMζ inhibition in the amygdala, but not in the hippocampus, can disrupt fear memory. This suggests that PKMζ may only maintain select forms of memory in specific brain structures and does not participate in a universal memory storage mechanism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Separating habit and recollection in young and older adults: Effects of elaborative processing and distinctiveness.

An extension of L. L. Jacoby's (1991) process-dissociation procedure was used to examine the effects of aging on recollection and automatic influences of memory (habit). Experiment 1 showed that older adults were impaired in their ability to engage in recollection but did not differ from young adults in their reliance on habit. Elderly adults were also less able to exploit distinctive contextual information to enhance recollection. Experiments 2 and 3 showed that with more supportive conditions, older adults were able to benefit from distinctive contextual information. Quantitative and qualitative deficits in recollective abilities are interpreted within a dual-process model of memory. The problem of distinguishing between a deficit in recollection and a deficit in inhibitory processes in older adults (e. g., L. Hasher & R. T. Zacks, 1998) and the importance of this distinction for purposes of repairing memory performance are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Effects of optimism, pessimism, and trait anxiety on ambulatory blood pressure and mood during everyday life": Correction to R?ikk?nen et al. (1999).

Reports an error in the original article by K. R?ikk?nen et al (Journal of Personality and Social Psychology, 1999, 76(1), 104–113). Table 4 on page 111 contained an error. The 4 sets of column heads ("Adjusted" and "Unadjusted") were inadvertently transposed. The corrected table is provided. (The following abstract of this article originally appeared in record 1999-00166-008): This study tested whether dispositional measures of optimism, pessimism, and anxiety affected ambulatory blood pressure (BP) and mood and whether any cardiovascular effects of dispositions were moderated by mood. Pessimistic and anxious adults had higher BP levels and felt more negative and less positive than did optimists or low anxious adults throughout the monitoring. The few times that optimists did feel negative were associated with levels of BP as high as those observed among pessimists or anxious individuals, regardless of their mood. To the extent that trait anxiety measures neuroticism, these findings suggest that neuroticism is directly related to health indicators rather than simply to illness behavior. Furthermore, the results suggest that pessimism has broad physiological and psychological consequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

COMT val158Met and executive control: A test of the benefit of specific deficits to translational research.

The role of catechol-O-methyltransferase (COMT) val158met in prefrontal cortical deficits associated with the liability to schizophrenia remains controversial. This study evaluated 464 healthy adult participants using three measures of executive functions in working memory: a 3-back version of the N-back continuous performance task (CPT) and two variants of the AX-CPT. The interpretability of N-back performance was confounded by possible generalized deficits, whereas the AX variants included internal controls for uncovering specific deficits. There was no relationship between the COMT genotype and N-back performance, whereas val/val individuals had a specific deficit on a dot-pattern version of the AX-CPT. In this case, a specific executive function known as context processing appeared to be compromised. These data suggest that the interpretability gained by including task manipulations to uncover specific deficits can enhance associations between cognitive and genetic levels of analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Words, imagination, meaning: Toward change.

Discusses imaginative literature as a therapeutic intervention in psychology and describes the change mechanisms existing within literature and the therapeutic components created through the use of literature. Bibliotherapy research is reviewed, including studies using specific theoretical approaches, populations, and purposes. Selections from narrative works illustrate various therapeutic applications of literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Foamed rigid vinyl for building products

PVC foamed building products have seen good growth lately because of their favorable properties and economics. Continued good growth is seen for the future. Expanding application areas, especially in the U.S. market, have created a need for knowledge on formulation and processin prarameters. Application areas are explored as well as raw material considerations, processing methods and parameters, and final physical properties.