Contact areas in the thumb carpometacarpal joint

The thumb carpometacarpal joint is a common site of osteoarthritis. It has been hypothesized that peaks of localized stress on the dorsoradial or volar-ulnar regions, or both, of the articular surfaces of the trapezium and metacarpal lead to erosion of cartilage and may be responsible for the progression of the disease. The objective of this study was to determine the contact areas in this joint under the functional position of lateral (key) pinch and in the extremes of range of motion of the joint. These contact areas were assessed relative to the observed sites of cartilage thinning. Eight hands from cadavers of women and five from cadavers of men were tested in vitro with the thumb under a 25 N load in the lateral pinch position, and under small muscle loads (0-5 N) with the thumb in flexion, extension, abduction, adduction, and neutral positions. Contact areas of articular surfaces of the thumb carpometacarpal joint were determined for these positions using a stereophotogrammetric technique. The lateral pinch position produced contact areas predominantly on the central, volar, and volar-ulnar regions of the trapezium and the metacarpal. In three specimens, contact areas were distinctly separated between the dorsoradial and volar-ulnar regions, and in one specimen, from a man, contact occurred exclusively on the dorsoradial region of the trapezium. Using stereophotogrammetry, maps of cartilage thickness also were determined for a subset of nine specimens. The volar-ulnar, ulnar, and dorsoradial regions of the trapezium were the most common sites of thin cartilage, and these may be sites of cartilage wear.(ABSTRACT TRUNCATED AT 250 WORDS)     

Induced chemiluminescence of oxidized fatty acids and oils

The injection of a strong organic base into milligram quantities of fats and oils dissolved in methylene chloride results in a burst of chemiluminescence whose peak intensity is a function of the previous thermal oxidation history and of the degree of unsaturation of the starting material. The flash of this induced chemiluminescence can be 10⁸ times higher than the steady-state “spontaneous” chemiluminescence. The kinetics of the induced chemiluminescence are first order in concentration and second order in time. The emission spectrum is broad and extends into the near infrared. A model based on dioxetane chemiluminescence is proposed to explain the observed kinetics.     

Macromers by carbocationic polymerization

Polymer Bulletin - Copolymerization of α-(p-vinylphenyl) polyisobutylene(p-polyisobutenylstyrene, PIB-St) with styrene (St) in emulsion has been investigated. Copolymerization occurs only when...     

HARDBALL: Local Government’s Foray Into Sports Franchise Ownership

Smaller cities seeking new economic development vehicles have embraced the growth of minor league sports. In an attempt to eliminate the threat of competition and maintain a sense of stability, four local governments purchased their respective minor league baseball franchise. This action may serve as a model for local governments that have invested heavily in professional sports as an economic development strategy. This study investigates the benefits of ownership in terms of stability for development, economic gain, and increased civic spirit. The study finds that publicly owned teams can be successfully used to anchor comprehensive plans for economic development, and that public ownership provides a way to pay the costs of the sports facilities and the debt service. There is little evidence to show that publicly owned teams increase civic spirit. However, this model presents some challenges that may prevent its widespread utilization.     

Heavy metal content of the hair of children in industrial cities

Nuchal screening has the following advantages: Non invasive. First trimester procedure. Results are obtained quickly. 80-90% detection rate for Down's Syndrome.     

Does the medium matter? The interaction of task type and technology on group performance and member reactions.

Investigated the hypothesis that as group tasks pose greater requirements for member interdependence, communication media that transmit more social context cues will foster group performance and satisfaction. 72 3-person groups of undergraduates worked in either computer-mediated or face-to-face meetings on 3 tasks with increasing levels of interdependence: an idea-generation task, an intellective task, and a judgment task. Results showed few differences between computer-mediated and face-to-face groups in the quality of the work completed but large differences in productivity favoring face-to-face groups. Analysis of productivity and of members' reactions supported the predicted interaction of tasks and media, with greater discrepancies between media conditions for tasks requiring higher levels of coordination. Results are discussed in terms of the implications of using computer-mediated communication systems for group work. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Water deprivation enhances fear conditioning to contextual, but not discrete, conditional stimuli in rats.

Water-deprived and nondeprived rats were fear conditioned with a discrete tone CS and an aversive footshock unconditioned stimulus/stimuli (UCS). 24 and 48 hrs following conditioning, conditional fear to the tone CS and the context cues of the conditioning chamber, respectively, were assessed by measuring freezing behavior. Water deprivation had no effect on baseline responding to either tone or contextual stimuli. Following either 1 or 3 tone-shock pairings, however, water deprivation selectively enhanced conditional freezing to the contextual cues of the training chamber; conditional freezing to the tone was unaffected by water deprivation. These results are consistent with the view that water deprivation affects fear conditioning via an influence on the hippocampus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of attention in face encoding.

Ss studied faces in a full- or a divided-attention condition and then received a recognition test that included old faces, new faces constructed by combining facial features from previously studied faces ("conjunction faces"), and partly or completely new faces. Full- but not divided attention Ss responded "old" more often to old than to conjunction faces; all Ss responded "old" to these faces more often than to partially or completely new faces. Thus it is less attentionally demanding to encode facial features than it is to encode their interrelations. Dividing attention had identical effects on an incidental and an intentional learning group. Exp 3 demonstrated that dividing attention primarily affected explicit recollection rather than stimulus familiarity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)