Scapholunate dissociation in the skeletally immature carpus

Scapholunate dissociation is well documented as a condition occurring in adult patients. We report it in a 14-year-old female patient. Persistent wrist pain 9 months after a well healed fracture of the distal radius triggered further investigation. Dynamic clinical and radiological studies demonstrated the instability.     

On the Modeling of the Diffraction Pattern from Metal Nanocrystals

The powder diffraction patterns of spherical nanocrystals made of five different fcc metals were generated using atomistic models within a Molecular Dynamics simulation. Static and dynamic effects are interpreted and discussed within the framework of two different approaches, respectively, based on (1) a Reciprocal Space and (2) a Direct Space representation of diffraction. Chosen elements display a wide range of properties, especially related to material stiffness and elastic anisotropy, so to deeply challenge interpretation paradigms. The effect of the shape on static and dynamic features is also addressed.     

The psychobiology of dissociation and identification.

In response to K. S. Bowers's (see record 1988-16849-001) discussion of the unconscious, the present author suggests new research directions for the issues Bowers raises. The present author also notes that recent research data support the hypothesis that the common everyday trance has its psychobiological basis in the natural 90-min ultradian rhythms that alter such behaviors as cerebral hemispheric dominance and fantasy activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiological dissociation of recency and recognition memory

Event-related brain potentials (ERPs) were recorded during the test phases of two experiments. In experiment 1, subjects first studied two consecutively presented word lists. At test, they were presented with pairs of words, and were required to judge which word had been presented most recently. The test pairs were composed of two previously studied words, one drawn from each list, (Old+Old pairs), one previously studied and one new word (Old+New pairs), or two unstudied words (New+New pairs). At temporo-parietal electrodes, ERPs to Old+Old and Old+New pairs were both reliably more positive-going than those to New+New pairs. At electrode sites overlying prefrontal cortex, ERPs to Old+Old pairs attracting correct recency judgements were more positive, from around 300 ms onwards, than those elicited by the other classes of item, which did not differ from one another. In experiment 2, the test task was changed to one that required discrimination between Old+New items on the one hand, and Old+Old and New+New pairs on the other. ERPs to Old+Old and Old+New pairs once again differed from those to New+New pairs at temporo-parietal sites, but no differences were evident between the ERPs from frontal electrode sites. In line with the evidence from lesion studies, these findings suggest that judgements of relative recency depend upon processes, supported by the prefrontal cortex, additional to those that are necessary for recognition memory. They further suggest that these processes are activated rapidly and selectively in response to pairs of studied items when these must be discriminated on the basis of their relative recency of occurrence.     

A development of the oxyhemoglobin dissociation curve analyzer

The development and improvement of an oxyhemoglobin dissociation curve analyzer is described. PO2 electrode performance was improved by electrochemical means and circuits are described for processing the PO2 and pH signals from the analyzer. A circuit for automatically correcting the curve for Bohr shifts from pH 7.40 is described, and the performance of the Bohr shift unit is verified by experiment. The analyzer produces curves under standard conditions of PCO2 40 mmHg, pH 7.40, and 37 degrees C.     

Religious ritual and dissociation in India and Australia

Bone metastases, together with generalized bone resorption, represent the main complication in patients with advanced prostate cancer, and palliative treatments are required to delay the progression of the metastases and improve the quality of life of these patients. For this reason, the bisphosphonate clodronate was administered to 18 patients (clodronate group) from a total of 30, all of whom were receiving complete androgenic blockade; the remaining 12 formed the control group. Transiliac bone biopsies were taken at the beginning of the study and 6 months later to determine the effect of the bisphosphonate on the skeleton. The results were assessed by bone histomorphometry and showed, although without statistical significance between the groups, an antiresorptive effect of the clodronate expressed as the eroded surface/bone surface and as the osteoclast number/bone surface. However, the bone volume also decreased after 6 months of treatment. Similarly, osteoid formation decreased as indicated by the osteoid surface and by the osteoid volume, probably due to the effect of the drug on the osteoblasts. The mineralization rate was apparently slightly retarded in the clodronate group, although to a lesser degree than in the control group. The results confirm the antiresorptive effect of clodronate and its detrimental effect on osteoblast activity.     

Dislocation Effects on the Diffraction Line Profiles from Nanocrystalline Domains

A Pd nano-polycrystalline microstructure was simulated by molecular dynamics, including edge or screw dislocations in one of the 50 grains, so as to produce a realistic model of nanocrystalline domain with line defect. The same crystalline domain was also studied, with or without line defects, as a free-standing, isolated nanocrystal. Atomic coordinates of the selected domain were used to generate powder patterns by means of the Debye scattering equation, and these patterns were used as “experimental” data to test existing methods of line profile analysis in controlled condition, i.e., with known type and density of defects. Results show that the Krivolgaz–Wilkens theory of dislocation line broadening qualitatively agrees with the MD model, but errors can be larger than 50 pct. A critical issue arises from the instability of the Krivolgaz–Wilkens model when all line profile parameters are simultaneously refined: reasonable results can be obtained by fixing or restricting some parameters.