Hemispheric asymmetries for global and local visual perception: Effects of stimulus and task factors.

Although neurological and physiological studies indicate a right hemisphere superiority in global processing and a left hemisphere superiority in local processing of Navon-type hierarchical letters (D. Navon, 1977), most investigations of lateralized perception in healthy participants report neither asymmetry. In 6 experiments the authors examined the influence of attentional demands, stimulus properties, and mode of response on perceptual asymmetries for global and local perception. Consistent with their theoretical predictions, asymmetries were more robust on divided- than focused-attention tasks and in response to stimuli in which local and global levels were equally salient compared with those with greater global than local saliency. Contrary to their prediction, perceptual asymmetries were not influenced by the complexity of the motor response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis of acyl-S-pantetheine by rat liver microsomes

The synthesis of acyl-S-pantetheine was found to occur in rat liver microsomal preparations. The reaction required ATP and a metal ion as cofactors, a fatty acid and the reduced form of pantetheine for optimal activity. The K_m for pantetheine was 0.8 mM, for ATP 0.8 mM, and for oleic acid 0.3 mM. Mg²⁺ (20 mM), Mn²⁺ (5 mM), Ca²⁺ (5 mM), and Fe²⁺ (5 mM) produced approximately equal activity when all other conditions were optimal. The characterization of the product and other properties of the enzyme are described. The acyl-S-pantetheine formed does not act as an acyl donor in the acylation ofsn-glycerol-3-phosphate, 1,2-diacylglycerol, or lysolecithin.     

Synthesis of Stable NAD+ Mimics as Inhibitors for the Legionella pneumophila Phosphoribosyl Ubiquitylating Enzyme SdeC

Stable NAD⁺ analogues carrying single atom substitutions in either the furanose ring or the nicotinamide part have proven their value as inhibitors for NAD⁺-consuming enzymes. To investigate the potential of such compounds to inhibit the adenosine diphosphate ribosyl (ADPr) transferase activity of the Legionella SdeC enzyme, we prepared three NAD⁺ analogues, namely carbanicotinamide adenosine dinucleotide (c-NAD⁺), thionicotinamide adenosine dinucleotide (S-NAD⁺) and benzamide adenosine dinucleotide (BAD). We optimized the chemical synthesis of thionicotinamide riboside and for the first time used an enzymatic approach to convert all three ribosides into the corresponding NAD⁺ mimics. We thus expanded the known scope of substrates for the NRK1/NMNAT1 enzyme combination by turning all three modified ribosides into NAD⁺ analogues in a scalable manner. We then compared the three NAD⁺ mimics side-by-side in a single assay for enzyme inhibition on Legionella effector enzyme SdeC. The class of SidE enzymes to which SdeC belongs was recently identified to be important in bacterial virulence, and we found SdeC to be inhibited by S-NAD⁺ and BAD with IC₅₀ values of 28 and 39 μM, respectively.     

Language, cognition, and the right hemisphere: A response to Gazzaniga.

Responds to M. S. Gazzaniga's (see record 1984-07149-001) review of right-hemisphere language in split-brain patients. The present author disagrees with (1) Gazzaniga's assumption that any capacity to extract meaning from spoken or written words is indicative of linguistic competence, and (2) Gazzaniga's claim that the right hemisphere is passive and nonresponsive. The present author provides evidence that, although the right hemisphere is nonlinguistic, it is active, highly intelligent, thinking, conscious, and fully human. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Handwriting posture and cerebral organization: How are they related?

Since J. Levy and M. Reid (see PA, Vols 57:5149 and 61:12570) first reported an association between handwriting posture and cerebral lateralization, a number of studies related to this issue have appeared in the literature. There is currently a great deal of controversy regarding the nature of the association between handwriting posture and brain organization. It is argued that this controversy loses much of its force when clinical data regarding functional lateralization in left-handers are taken into account. The relevant background on brain organization in left-handers, Levy and Reid's findings and studies related to their findings, and Levy and Reid's speculations with respect to possible interpretations of their data and research bearing on those speculations are reviewed and discussed. (2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interhemispheric cooperation: Left is left and right is right, but sometimes the twain shall meet.

Interhemispheric cooperation in the processing of nonsense syllables projected simultaneously to both hemispheres was investigated in 2 experiments. Stimuli were projected unilaterally in the left and right visual fields (LVF, RVF) and bilaterally (the same syllable in both fields, BVF; Exp 1, 64 right-handed Ss) or centrally (CVF; Exp 2, 32 right-handed Ss). Accuracy and error patterns differed for the LVF and RVF. Error patterns were intermediate for the BVF–CVF and were partly shifted toward the RVF for Ss with large RVF advantages and toward the LVF for those with small asymmetries. Regression analyses showed that variance in BVF–CVF error patterns was jointly predicted by LVF and RVF variances. Both hemispheres, as demonstrated by means and regression analyses, contribute to the processing of bihemispherically presented syllables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Drag-and-drop multimedia: ¶an interface framework for digital libraries

In this paper, we describe a new interface for querying multimedia digital libraries and an interface building framework. The interface employs a drag-and-drop style of interaction and combines a structured natural-language style query specification with reusable multimedia objects. We call this interface DanDMM, short for “drag-and-drop multimedia”. DanDMM interfaces capture the syntax of the underlying query language, and dynamically reconfigure to reflect the contents of the data repository. A distinguishing feature of DanDMM is its ability to synthesize integrated interfaces that incorporate both example-based specification using multimedia objects, and traditional techniques including keyword, attribute, and free text-based search. We describe the DanDMM-builder, a framework for synthesizing DanDMM interfaces, and give several examples of interfaces that have been constructed using DanDMM-builder, including a remote-sensing library application and a video digital library. Received: 15 December 1997 / Revised: June 1999