Continuous separation of particles from macromolecules in split-flow thin (SPLITT) cells

A split-flow thin (SPLITT) cell with a perpendicular driving force of one gravity has been utilized for the rapid separation of micron-sized particles from macromolecules. The procedure involves the simultaneous use of two transport mechanisms and thus two operating modes: a sedimentation process controls the displacement of the particles across the thickness of the thin channel, while diffusion controls the displacement of macromolecules. The theoretical equations for these two operating modes are summarized and it is shown how the two modes can be combined to yield specified recovery factors. The theory was tested on a mixture of 10 μm polystyrene latex beads and three different proteins. The observed separation was in excellent agreement with theory. Attempts to fractionate red blood cells and plasma proteins from whole blood were only partially successful as a consequence of the weak sedimentation of red blood cells. Various remedies to this problem are suggested, the most promising of which is the use of a SPLITT cell subject to mild centrifugal forces.     

Editorial.

This editorial introduces the current issue of the Journal of Educational Psychology. This issue embarks on a year-long celebration through which we recognize 100 years of our parent organization, the American Psychological Association, in the business of psychology. The Journal's contribution to the celebration is the following: In each 1992 issue, we will publish one or more special articles, special in the sense that these articles have been solicited rather than submitted and in the sense that they reflect on selected aspects of the science and status of educational psychology as we approach the 21st century. In addition, each issue will contain a centennial-year surprise—a reprinted article from an earlier issue of the Journal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What is a specialist? The role of board certification in occupational medicine

A shortage of occupational medicine physicians exists for which a number of solutions have been proposed. The lack of board-certified specialists to address the increasingly complex issues encountered in this area of medicine has contributed to a credibility and identity crisis within the occupational medicine community. This article will review the significance of board certification and its importance for enhancing and preserving the specialty of occupational medicine.     

An automated system for investigating the thermal properties of crystallizing polymers

Equipment for investigating crystal-melt-crystal phase transitions in polymers of the polyethylene oxide group by the differential thermal analysis (DTA) method is described. An original construction is proposed which enables DTA thermograms to be recorded automatically with computer processing of the results obtained. __________ Translated from Izmeritel’naya Tekhnika, No. 2, pp. 45–46, February, 2006.     

Heat shock protein 27 kDa expression and phosphorylation regulates endothelial cell migration

The effects of enhanced HSP27 expression or expression of a nonphosphorylatable form of HSP27 on the migration of bovine arterial endothelial cells was assessed. Expression of the wild-type protein enhanced migration by twofold compared to control transfectants, whereas expression of the mutant protein retarded migration by 40%. Since homologs of the small heat shock protein inhibit F-actin polymerization in vitro and may alter basolateral F-actin content in vivo, it was postulated that the 27 kDa heat shock protein affects microfilament extension essential for cell motility. Expression of the wild-type protein promoted the generation of long cellular extensions, whereas expression of the dominant negative mutant protein resulted in a marked reduction of lamellipodia and generated aberrant microfilament morphology at the wound edge. Immunofluorescence combined with phalloidin staining demonstrated the colocalization of the HSP27 gene products with lamellipodial microfilament structures. These data suggest that the 27 kDa heat shock protein regulates migration by affecting the generation lamellipodia microfilaments.     

Predictors of outcome following severe head trauma: follow-up data from the Traumatic Coma Data Bank

Outcome as a function of employment status or return to school was evaluated in severely head-injured patients. A priori we selected the most salient demographic, physiological, neuropsychological and psychosocial outcome predictors with the aim of identifying which of there variables captured at baseline or 6 months would best predict employability at 6 or 12 months. Based on the patients evaluated at 6 months, 18% of former workers had returned to gainful employment and 62% of former students had returned to school. For those not back to work or school at 6 months, 31% of the former workers and 66% of the former students had returned by 12 months. Age, length of coma, speed for both attending and motor movements, spatial integration, and intact vocabulary were all significantly related to returning to work or school. The three most potent predictors for returning to work or school were intactness of the patient's verbal intellectual power, speed of information processing and age.