Urokinase-type plasminogen activator receptor reversibly dissociates from complement receptor type 3 (alpha M beta 2' CD11b/CD18) during neutrophil polarization

Previous studies have shown that the leukocyte integrin CR3 (CD11b/CD18) is physically associated with the urokinase-type plasminogen activator receptor (uPAR;CD87), a glycosyl-phosphatidylinositol (GPI)-linked protein, in resting neutrophil membranes. We now show that uPAR-to-CR3 interactions are reversible, correlating with cell shape. Neutrophils were first labeled with fluorescein conjugates of anti-CR3 F(ab')2 fragments followed by capping using a second-step F(ab')2 directed against murine F(ab')2s. Cells were then probed using rhodamine-conjugated anti-uPAR F(ab')2s. Although uPAR co-caps with CR3 on resting cells, uPAR was found to dissociate or "uncap" coincident with spontaneous cell polarization for migration. CR3 caps transformed into uropods while uPAR accumulated at lamellipodia of polarized cells. Capping was unnecessary for the observed distribution of CR3 and uPAR since the anti-CR3 and anti-uPAR F(ab')2s traffic to the uropod and lamellipodium, respectively, during polarization of uncapped cells. These receptors reassociate when cells return to a spherical morphology. In contrast to uPAR, Fc gamma RIIIB did not dissociate from CR3 caps during cell polarization. Resonance energy transfer (RET) microscopy was used to image the spatial distribution of RET and to follow the kinetics of association and dissociation. Initial levels of RET dramatically fell during cell polarization, but did not change on cells fixed with paraformaldehyde. Receptor reassociation was a biphasic process with initial reassociation about the perimeter of a cap, followed by a plateau and a slower rise in RET within a cap. We suggest that cells regulate receptor-receptor associations depending upon their physiologic activities.     

Relative effectiveness of four combinations of oral and written presentations of job related information to disadvantaged trainees.

Hypothesized that conditions in which an oral presentation was given before a written presentation of information would be more effective than if a written presentation preceded an oral one. Ss were 73 trainees in a program for the disadvantaged (mean age, 22.3 yrs). 4 different combinations of oral and written messages were administered to each of 4 groups. The criterion of effectiveness was a multiple choice test which measured Ss' knowledge of the information in the message. 8 a priori comparisons based on the hypothesis were in the expected direction, but only 3 were significant (p     

Understanding the Crystal Packing and Organic Thin‐Film Transistor Performance in Isomeric Guest–Host Systems

In order to understand how additives influence the structure and electrical properties of active layers in thin‐film devices, a compositionally identical but structurally different guest–host system based on the syn and anti isomers of triethylsilylethynyl anthradithiophene (TES ADT) is systematically explored. The mobility of organic thin‐film transistors (OTFTs) comprising anti TES ADT drops with the addition of only 0.01% of the syn isomer and is pinned at the mobility of OTFTs having pure syn isomer after the addition of only 10% of the isomer. As the syn isomer fraction increases, intermolecular repulsion increases, resulting in a decrease in the unit‐cell density and concomitant disordering of the charge‐transport pathway. This molecular disorder leads to an increase in charge trapping, causing the mobility of OTFTs to drop with increasing syn‐isomer concentration. Since charge transport is sensitive to even minute fractions of molecular disorder, this work emphasizes the importance of prioritizing structural compatibility when choosing material pairs for guest–host systems.     

Langmuir-Blodgett films: a new class of pyroelectric materials

The authors report on a novel method for producing the noncentrosymmetric structures necessary for the observation of the pyroelectric effect. The Langmuir-Blodgett technique has been used to fabricate ultrathin films consisting of alternate layers of 22-tricosenoic acid and 1-docosylamine. The pyroelectric coefficient has been determined using both static and dynamic detection techniques, is approximately 0.2 nC cm(-2) K(-1) (static value); this value is independent of the film thickness in the range of 11 to 99 monolayers, but increases slightly if a substrate of lower thermal expansion coefficient is used. The results indicate that there is a piezoelectrically induced secondary effect contributing to the overall pyroelectric activity.     

The effects of majority versus minority source status on persuasion: A self-validation analysis.

The present research proposes that sources in the numerical majority (vs. minority) can affect persuasion by influencing the confidence with which people hold their thoughts in response to the persuasive message. Participants received a persuasive message composed of either strong or weak arguments that was presented by a majority or a minority source. Consistent with the self-validation hypothesis, we predicted and found that the majority (vs. minority) status of the source increased the confidence with which recipients held their thoughts. As a consequence, majority (vs. minority) sources increased argument quality effects in persuasion when source status information followed message processing (Experiment 1). In contrast, when the information regarding source status preceded (rather than followed) the persuasive message, it validated the perception of the position advocated, reducing message processing. As a consequence of having more confidence in the position advocated before receiving the message, majority (vs. minority) sources reduced argument quality effects in persuasion (Experiment 2). Finally, Experiment 3 isolated the timing of the source status manipulation, revealing that sources in the numerical majority (vs. minority) can increase or decrease persuasion to strong arguments depending on whether source status is introduced before or after processing the message. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The mere perception of elaboration creates attitude certainty: Exploring the thoughtfulness heuristic.

Attitude theory has long proposed a mechanism through which antecedents of message elaboration produce attitude strength consequences. However, little direct evidence exists for the intervening process. The proposed thoughtfulness heuristic holds that perceiving that more thought has taken place leads to greater attitude certainty. Two roles were established for this heuristic: first as a mediator of the impact of antecedents of elaboration on attitude certainty and second as a way to influence attitude certainty independent of actual elaboration. In Studies 1 and 2, antecedents of elaboration (need for cognition, distraction) impacted attitude certainty because they impacted the actual amount of processing, which in turn affected perceptions of the amount of processing. In Studies 3 and 4, a manipulation of perceived thought impacted certainty independent of actual thought (i.e., after thinking had already occurred). Furthermore, the thoughtfulness heuristic was shown to influence behavioral intentions, establishing perceived amount of processing as both a mediator and an independent cause of attitude strength consequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clinical pharmacokinetics of 1-[((S)-2-hydroxy-2-oxo-1,4,2-dioxaphosphorinan-5-yl)methyl]cytosine in human immunodeficiency virus-infected patients

Gene 3 protein (pIII), a minor coat protein at one end of the filamentous bacteriophage fd, is involved in initiating the infection by the virus of Escherichia coli cells that display an F-pilus. Infection is thought to start with the adsorption of the D2 domain of pIII to the tip of the pilus, retraction of the pilus, and penetration of the E. coli cell membrane mediated by an interaction between the D1 domain of pIII and the Tol protein complex in the membrane. A subgene encoding the pIII-D1D2 di-domain was created, and the subgene was successfully overexpressed in E. coli cells. Domains D1 and D2 were separated after limited proteolysis of a modified pIII-D1D2 (designated pIII-D1D2.trp) into which two tryptic cleavage sites were introduced at appropriate points. The purified pIII-D1D2 di-domain and pIII-D2 domain were able to bind to the F-pilus, competing with the wild-type pIII and delaying infection by the intact filamentous phage. The pIII-D1 domain was unable to bind to the F-pilus by this criterion. This provides conclusive evidence that the pIII-D2 domain is responsible for the adsorption to the tip of the F-pilus and can achieve this in the absence of domain D1, opening the way to identifying the molecular basis of the interaction of pIII-D2 with the pilus.     

Contextual Moderation of Racial Bias: The Impact of Social Roles on Controlled and Automatically Activated Attitudes.

Three experiments tested the hypothesis that the social roles implied by specific contexts can attenuate or reverse the typical pattern of racial bias obtained on both controlled and automatic evaluation measures. Study 1 assessed evaluations of Black and Asian faces in contexts related to athlete or student roles. Study 2 compared evaluations of Black and White faces in 3 role-related contexts (prisoner, churchgoer, and factory worker). Study 3 manipulated role cues (lawyer or prisoner) within the same prison context. All 3 studies produced significant reversals of racial bias as a function of implied role on measures of both controlled and automatic evaluation. These results support the interpretation that differential evaluations based on Race X Role interactions provide one way that context can moderate both controlled and automatic racial bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)