Identification of the major synaptojanin-binding proteins in brain

Synaptojanin is a nerve-terminal enriched inositol 5-phosphatase thought to function in synaptic vesicle endocytosis, in part through interactions with the Src homology 3 domain of amphiphysin. We have used synaptojanin purified from Sf9 cells after baculovirus mediated expression in overlay assays to identify two major synaptojanin-binding proteins in rat brain. The first, at 125 kDa, is amphiphysin. The second, at 40 kDa, is the major synaptojanin-binding protein detected, is highly enriched in brain, is concentrated in a soluble synaptic fraction, and co-immunoprecipitates with synaptojanin. The 40-kDa protein does not bind to a synaptojanin construct lacking the proline-rich C terminus, suggesting that its interaction with synaptojanin is mediated through an Src homology 3 domain. The 40-kDa synaptojanin-binding protein was partially purified from rat brain cytosol through a three-step procedure involving ammonium sulfate precipitation, sucrose density gradient centrifugation, and DEAE ion-exchange chromatography. Peptide sequence analysis identified the 40-kDa protein as SH3P4, a member of a novel family of Src homology 3 domain-containing proteins. These data suggest an important role for SH3P4 in synaptic vesicle endocytosis.     

On intelligence testing and immigration legislation.

Criticizes M. Snyderman and R. J. Herrnstein's (see record 1984-09428-001) discussion of how and to what extent intelligence test data influenced the passage of the 1924 Immigration Act. The present author argues against Snyderman and Herrnstein's claim, based on a lack of reference in the Congressional Record, that intelligence testing had no influence on the law's passage. It is also noted that Snyderman and Herrnstein's general point has been made elsewhere, although they appear unaware of it. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is psychology the science of behavior?

Discusses some of the reasons for, and consequences of, the custom in research of disregarding the complexity and nuances of behavior in favor of observing and measuring single facets of it. The roots of this practice appear to have started with the pioneer psychologists' determined efforts to demonstrate that their subject matter was tangible, not psychic, and that it was natural and not supernatural. This defensiveness initiated the still persisting and widely sanctioned practice of playing up the kinship of psychology with biology and playing down its independence and uniqueness. The adoption of the methods of the physical sciences also led to an emphasis on regularity and thus to a slighting of the irregularity that is characteristic of behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A 3-V fully differential distributed limiting driver for 40-Gb/s optical transmission systems

A fully differential 40-Gb/s electro-absorption modulator driver is presented. Based on a distributed limiting architecture, the circuit can supply up to 3.0-V/sub pp/ (peak-to-peak) per side in a 50-/spl Omega/ load at data rates as high as 44 Gb/s. Both the input and the output are internally matched to 50 /spl Omega/ and exhibit return loss of better than 10 dB up to 50 GHz. Additional features of the driver include the use of a single -5.2-V supply, output swing control (1.7-3.0-V/sub pp/ per side), dc output offset control (-0.15 V to -1.1 V), and pulsewidth control (30% to 66%). The driver architecture was optimized based on a comprehensive analytical derivation of the frequency response of cascaded source-coupled field-effect transistor logic blocks using both single and double source-follower topologies.     

Rheological characterization of a charged cationic hydrogel network across the gelation boundary

The in situ rheological behavior across the gelation threshold has been investigated for an affine network of a completely charged cationic monomer (3-acrylamidopropyl)-trimethylammonium chloride (APTMAC1) when it is crosslinked with a neutral crosslinker (N,N′-methylenebisacrylamide) to form a fully charged novel cationic hydrogel. The elastic moduli (G′) near the gel point (during the crosslinking or ‘curing’ process) show a power law dependence of the form G′(t)=ε^z, where ε=((t−t_c)/t_c) is the distance from the gel point (t_c). The critical exponent, z, for the hydrogel series investigated is estimated to be 1.5, slightly lower than the predictions based on percolation theory (z∼1.7-1.9). From the equilibrium (after the curing process) rheological measurements of a series of samples, it is inferred that there is a critical crosslinker mole percent (X_c) with respect to the monomer concentration, required to form a well-defined three-dimensional network with a solid-like behavior. The value of this X_c is found to be between 0.5 and 1%. The theoretically predicted value of X_c using the percolation theory (for the percolation of crosslinks, G₀(X)∝[|X−X_c|/X_c]^z) and the exponent estimated from the in situ measurements (z=1.5), is X_c∼0.6, which is in good agreement with the experiments. The results may have applicability in translating from bulk systems to the nanoscale in hydrogel design.     

Transient temperatures produced by abrasion of aragonite

The transformation of aragonite to calcite has been used to provide an indication of the thermal history of debris and the surface of aragonite during abrasion on 320 grade silicon carbide papers. The temperature rise of debris was estimated to be 500°–600°C whereas the specimen surface temperature was considerably lower. This supports the view that the mechanism of material removal during the abrasion of non metallic materials is essentially similar to that occurring in metals.     

The fuzzy Hough transform-feature extraction in medical images

Identification of anatomical features is a necessary step for medical image analysis. Automatic methods for feature identification using conventional pattern recognition techniques typically classify an object as a member of a predefined class of objects, but do not attempt to recover the exact or approximate shape of that object. For this reason, such techniques are usually not sufficient to identify the borders of organs when individual geometry varies in local detail, even though the general geometrical shape is similar. The authors present an algorithm that detects features in an image based on approximate geometrical models. The algorithm is based on the traditional and generalized Hough Transforms but includes notions from fuzzy set theory. The authors use the new algorithm to roughly estimate the actual locations of boundaries of an internal organ, and from this estimate, to determine a region of interest around the organ. Based on this rough estimate of the border location, and the derived region of interest, the authors find the final (improved) estimate of the true borders with other (subsequently used) image processing techniques. They present results that demonstrate that the algorithm was successfully used to estimate the approximate location of the chest wall in humans, and of the left ventricular contours of a dog heart obtained from cine-computed tomographic images. The authors use this fuzzy Hough transform algorithm as part of a larger procedure to automatically identify the myocardial contours of the heart. This algorithm may also allow for more rapid image processing and clinical decision making in other medical imaging applications.     

Critical issues for e‐learning delivery: what may seem obvious is not always put into practice

Abstract The successful adoption of information and communication technology to enhance learning can be very challenging, requiring a complex blend of technological, pedagogical and organizational components, which may at times require the resolution of contradictory demands and conflicting needs. The research reported in this paper investigated and analysed critical success factors (CSFs) that are required to deliver e‐learning within higher education (HE) courses and programmes. The research design adopted a critical research approach, instantiated by focus group discussions with e‐learning experts drawn from administrative, educational, technology and research domains. The findings revealed that staffing issues, pedagogically sound delivery models and training of both tutors and students cannot be treated as trivial issues and are critical to the success of e‐learning. Furthermore, this research also shows that there is a strong relationship between these factors and inspirational institutional leadership. The findings also suggest that in order to assure the success of e‐learning, this leadership should guarantee the presence of institutional enablers. It is hoped that the CSFs, described and discussed in depth in this paper, will provide a suitable theoretical foundation to underpin the successful delivery of e‐learning within HE.