Acetylcholine receptor at neuromuscular junctions by EM autoradiography using mask analysis and linear sources

Several methods of analyzing EM autoradiograms are now available. Two such procedures, the grain density distribution (or histogram) method and the mask method use the resolution of the EM autoradiographic technique to generate grain distributions expected from postulated sources, and compare these with the observed grains in the autoradiograms. These two methods are here compared in the analysis of label on linear sources: the distribution of labeled acetylcholine receptor (AChR) down the postjunctional folds of lizard and frog neuromuscular junctions. The receptors were labeled with I-25-α-bungarotoxin and the autoradiograms coated with the high resolution Kodak emulsion 129–01. We found that both methods gave similar results in confirming that the bulk of the AChR is concentrated on the thickened region of the membrane at the top ∼2000 A of the junctional folds, and that there may be a gradient of receptor concentration down the folds. The grain density distribution method is simpler, but does not lend itself easily to quantifying the extent of deviation from simple models. Although computer graphics is not necessary for either method, its use allows the expected grains from linear sources to be generated quickly, making the mask analysis a feasible routine method for assigning the extent of label in different membrane regions.     

Mixed crystalline films of co-evaporated hydrogen- and fluorine-terminated phthalocyanines and their application in photovoltaic devices

Blends of organic electron and hole conductive materials are widely used for ambipolar charge carrier transport and photovoltaic cells. An obvious choice for donor–acceptor blends are organic semiconducting materials in their hydrogenated and fluorinated form, since they combine potentially suitable electronic properties with structural compatibility of the two constituents. This study focuses on the structural, optical, and electrical properties of blends using hydrogenated copper-phthalocyanine (H₁₆CuPc) in combination with its per-fluorinated version (F₁₆CuPc). Using X-ray scattering, scanning force microscopy and optical absorption measurements we show that mixed crystalline films are obtained by co-evaporation of the two materials. Electrical transport measurements reveal a profound reduction of the current for bipolar charge injection in mixed films. We discuss the formation of self-trapped charge transfer excitons as possible explanation for this unexpected behaviour, which impedes the usability of this system in photovoltaic cells.     

Methods for Compression of Feedback in Adaptive Multi-carrier 4G Schemes

In this paper, several algorithms for compressing the feedback of channel quality information are presented and analyzed. These algorithms are developed for a proposed adaptive modulation scheme for future multi-carrier 4G mobile systems. These strategies compress the feedback data and, used together with opportunistic scheduling, drastically reduce the feedback data rate. Thus the adaptive modulation schemes become more suitable and efficient to be implemented in future mobile systems, increasing data throughput and overall system performance.

0.2 μm AlSb/InAs HEMTs with 5 V gate breakdown voltage

DC and microwave measurements on AlSb/InAs HEMTs with a gate length of 0.21 μm are reported. The reverse gate characteristics exhibit relatively low gate leakage current and gate-drain breakdown voltages as high as 5 V. Equivalent circuit modelling yields an f_T of 110 GHz after removal of the gate bonding pad capacitance. The bias dependence of f_max is examined indicating a significant reduction in the unilateral gain due to impact ionisation     

Writing quality, reading skills, and domain knowledge as factors in text comprehension.

103 undergraduates listened to and recalled 3 passages and were given a general reading comprehension test. The passages were presented such that Ss could use general knowledge to understand them or such that no specific world knowledge seemed applicable. The passages were written in 2 different versions, preserving their content but varying their style. All 3 factors (domain knowledge, writing style, and skill) significantly affected reproductive recall, and there were no interactions between these factors. However, while good writing was sufficient to improve the reproduction of the texts, an analysis of the recall elaborations Ss made revealed that the correctness of their elaborations depended strongly on the availability of appropriate domain knowledge. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contribution to Shear Wrinkling of GFRP Webs in Cell-Core Sandwiches

Glass-fiber-reinforced polymer (GFRP) cell-core sandwiches are composed of outer GFRP face sheets, a foam core, and a grid of GFRP webs integrated into the core to reinforce the shear load capacity. One of the critical failure modes of cell-core sandwich structures is shear wrinkling, a local buckling failure in the sandwich webs because of shear loading. The shear wrinkling behavior of GFRP laminates with different laminate sequences, stabilized by a polyurethane foam core, was experimentally and numerically investigated. Shear wrinkling was simulated by a biaxial compression–tension setup. The results show that an increasing transverse tension load significantly decreases the wrinkling load. The decreasing effect of tension is explained by the lateral contraction because of Poisson’s effect, which causes an increase in the initial imperfections and subsequent accelerated bending.     

Are word representations abstract or instance-based? Effects of spelling inconsistency in orthographic learning.

In Experiment 1, 62 10-year-old children studied printed pseudowords with semantic information. The items were later represented in a different format for reading, with half of the items spelled in the same way as before and half displayed in a new phonologically equivalent spelling. In a dictation test, the exposure to an alternative spelling substantially increased the number of errors that matched the alternative spelling, especially in good spellers. Orthographic learning predicted word identification when accuracy on orthographic choice for words was controlled. In Experiment 2, the effects on dictation responses of exposure to a misspelling versus the correct spelling, and the interactive effect of spelling ability, were confirmed relative to a no-exposure control in adults. The results support a single-lexicon view of reading and spelling and have implications for abstractionist and instance-based theories of orthographic representations. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Neuropsychological functioning and personality characteristics of migrainous and nonmigrainous female college students.

Examined the theory that chronic migraine headaches can lead to permanent changes in brain function in 71 female college students. Ss were 20 classic migraineurs, 27 common migraineurs, and 24 controls. No significant group differences were found on the Halstead Reitan Neuropsychological Test Battery and additional memory tests. Classic migraineurs had significantly higher scores than common migraineurs on the Hysteria and Paranoia scales of the Minnesota Multiphasic Personality Inventory (MMPI) and significantly higher scores than the controls on Hypochondriasis and Hysteria scales. Explanations for the lack of cognitive deficits in this group are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Combined surgery of the mitral valve and the abdominal aorta in a case of Takayasu's disease

The authors report the case of a 34-year-old woman, of North African origin, with mitral valve disease and abdominal aortitis. The differential diagnosis between Takayasu' disease, embolism of cardiac origin and rheumatic aortitis is discussed. Treatment of these lesions was by combined cardiac and vascular surgery in a single-stage operation.     

On the relationship between lateralized brain function and orienting asymmetries: Correction to Teufel et al. (2010).

Reports an error in On the relationship between lateralized brain function and orienting asymmetries by Christoph Teufel, Asif A. Ghazanfar and Julia Fischer (Behavioral Neuroscience, 2010[Aug], Vol 124[4], 437-445). In the article, we wrote that “the likelihood of obtaining at least one significant result at p n. The probability of obtaining at least one significant result is therefore 1 — (1— α)n. (The following abstract of the original article appeared in record 2010-16138-001.) Hemispheric specializations for language perception constitute one of the classic topic in cognitive neuroscience. Evidence has accumulated to suggest that lateralized acoustic processing is not restricted to humans but is also found in numerous animal species. One of the methods used to track such lateralization is the orienting-asymmetry paradigm, a simple, noninvasive means to study lateralization that has been applied to a range of different species ranging from harpy eagles to humans. Here we summarize and compare the results of studies employing the orienting-asymmetry paradigm, showing that these studies yield largely inconsistent results. We critically discuss the methodology's implicit assumptions and conclude that the empirical inconsistencies produced by the orienting-asymmetry paradigm, and the lack of sufficient evidence supporting the paradigm's underlying assumptions, warrant serious caution when interpreting results obtained by the method. Nontrivial interpretations of orienting-asymmetry results will require a much better understanding of how lateralized brain functions interact with overt behaviors. (PsycINFO Database Record (c) 2011 APA, all rights reserved)