Putting the brakes on prejudice: On the development and operation of cues for control.

A model concerning the establishment and operation of cues for control was developed and tested to understand how control can be exerted over (automatic) prejudiced responses. Cues for control are stimuli that are associated with prejudiced responses and the aversive consequences of those responses (e.g., guilt). In Exp 1 and 2, 3 events critical to the establishment of cues occurred: behavioral inhibition, the experience of guilt, and retrospective reflection. In Exp 3, the presentation of already-established cues for control did, as expected, produce behavioral inhibition. In Exp 4, participants were provided with an experience in which cues could be established. Later presentation of those cues in a different task resulted in behavioral inhibition and less racially biased responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and characterization of iron-substituted hydroxyapatite via a simple ion-exchange procedure

Hydroxyapatite (HA), the main inorganic component of natural bones, is widely studied as a biomaterial due to its excellent biocompatibility and osteoinductivity. The crystal structure of HA lends itself to a wide variety of substitutions and ion doping, which allows for tailoring of material properties. In this study, iron-doped HA was synthesized via a simple ion-exchange procedure and characterized thoroughly for crystal structure and phase purity using X-ray diffraction, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectroscopy, and Fourier transform infrared spectroscopy. Magnetic properties were studied using vibrating sample magnetometer and superconducting quantum interference device analysis. Ion-exchange was attempted using both ferric and ferrous chloride iron solutions, but a substitution was only achieved using ferric chloride solution. The results showed that after iron substitution the powder retained characteristic apatite crystal structure and functional groups, but the iron-doped samples displayed paramagnetic properties, as opposed to the diamagnetism of pure HA. The effect of soaking time on iron content was also examined, and collectively X-ray diffraction and inductively coupled plasma atomic emission spectroscopy results suggested that an increase in soaking time led to an increase in iron content in the sample powder. Iron-substituted HA nanoparticles, a biomaterial with magnetic properties, could be a promising biomaterial to be used in a variety of biomedical fields, including magnetic imaging, drug delivery, or hyperthermia-based cancer treatments.     

Low‐Field Magnetoresistance in La0.67Sr0.33MnO3:ZnO Composite Film

A nanocomposite film of La_0.67Sr_0.33MnO₃ (LSMO):ZnO is synthesized by depositing LSMO solution on a vertical array of ZnO nanorods grown on (0001) Al₂O₃ substrate. The magnetic behavior of the composite film differs from that of a pure LSMO film, possibly due to smaller grain size in the composite, small amount of Zn doping, or the presence of nonmagnetic ZnO phase near the LSMO grain boundaries. Magnetotransport measurements show that the low‐field magnetoresistance (LFMR) of the nanocomposite film is significantly enhanced as compared to that observed for pure LSMO film. The highest value of the LFMR of the nanocomposite film at 10 K is –23.9% with a magnetic field of 0.5 T applied parallel to the current.     

Measuring in vitro biotransformation rates of super hydrophobic chemicals in rat liver s9 fractions using thin-film sorbent-phase dosing

Methods for rapid and cost-effective assessment of the biotransformation potential of very hydrophobic and potentially bioaccumulative chemicals in mammals are urgently needed for the ongoing global evaluation of the environmental behavior of commercial chemicals. We developed and tested a novel solvent-free, thin-film sorbent-phase in vitro dosing system to measure the in vitro biotransformation rates of very hydrophobic chemicals in male Sprague-Dawley rat liver S9 homogenates and compared the rates to those measured by conventional solvent-delivery dosing. The thin-film sorbent-phase dosing system using ethylene vinyl acetate coated vials was developed to eliminate the incomplete dissolution of very hydrophobic substances in largely aqueous liver homogenates, to determine biotransformation rates at low substrate concentrations, to measure the unbound fraction of substrate in solution, and to simplify chemical analysis by avoiding the difficult extraction of test chemicals from complex biological matrices. Biotransformation rates using sorbent-phase dosing were 2-fold greater than those measured using solvent-delivery dosing. Unbound concentrations of very hydrophobic test chemicals were found to decline with increasing S9 and protein concentrations, causing measured biotransformation rates to be independent of S9 or protein concentrations. The results emphasize the importance of specifying both protein content and unbound substrate fraction in the measurement and reporting of in vitro biotransformation rates of very hydrophobic substances, which can be achieved in a thin-film sorbent-phase dosing system.     

Directed collagen patterning on gold-coated silicon substrates via micro-contact printing

The ability to create biologically functional systems from non-biological materials has importance in the arena of tissue engineering and medical device implantation. Directing the immobilization of proteins to specified regions on a substrate has attracted a lot of attention as one potential approach. Functionalization of the surface of gold-coated silicon wafers was accomplished by micro-contact printing a hydrophilic (or hydrophobic) self-assembled monolayer (SAM) atop the gold coating using poly(dimethylsiloxane) (PDMS) stamps. Afterwards, the substrate was soaked in a solution of hydrophobic (or hydrophilic) surfactant molecules which filled in the un-stamped area. The intention was to use carbodiimide coupling to attach fluorescently labeled collagen to COOH-terminated (hydrophilic) regions of the substrate. However, even in the presence of the reagents for this reaction, the collagen preferred to assemble on the hydrophobic regions. The results suggest that micro-contact printing may provide a simple mechanism for patterning collagen onto surfaces simply using selective adsorption. This might be useful for examining directed cell interactions, or to enhance the biocompatibility of inorganic materials used as substrates in tissue engineering or devices that are to be implanted into the body.     

Sports participation and juvenile delinquency: The role of the peer context among adolescent boys and girls with varied histories of problem behavior.

In a study of 1,344 urban adolescents, the authors examined the relation between participation in organized sports and juvenile delinquency. They compared youth who participated in sports to those who only participated in nonathletic activities and to those who did not participate in any organized activities. They also examined the indirect relations between sports and delinquency via 2 peer-related constructs—deviant peer affiliations and unstructured socializing. Finally, they examined the extent to which gender and prior externalizing problems moderated the direct and indirect relations between sports participation and delinquency. The authors found that the odds of nonviolent delinquency were higher among boys who participated in sports when compared to boys who participated only in nonathletic activities but not when compared to boys who did not participate in any organized activities. Deviant peer affiliations and unstructured socializing mediated the relation between sports participation and boys' nonviolent delinquency. Moreover, prior externalizing problems moderated the mediated path through peer deviance. The authors did not, however, find direct, mediated, or moderated relations between sports and boys' violent delinquency nor between sports and girls' violent or nonviolent delinquency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adolescents' participation in organized activities and developmental success 2 and 8 years after high school: Do sponsorship, duration, and intensity matter?

Using data from the National Education Longitudinal Study, the authors examined relations between educational, civic, and occupational success in young adulthood and the duration and intensity of participation in organized activities during high school. They also examined these relations as a function of sponsorship (i.e., school- vs. community-sponsored organized activities). They found that youths who participated in organized activities for 2 years demonstrated more favorable educational and civic outcomes in young adulthood than those who participated for 1 year. More intensive participation was also associated with greater educational, civic, and occupational success in young adulthood--particularly among youths who participated in activities for 2 years. Educational attainment often mediated the relations between temporal measures of participation and young adult civic and occupational outcomes. With the exception of analyses examining occupational success, findings varied little as a function of sponsorship. Of note, analyses revealed that both temporal measures of participation were positively associated with young adult outcomes as many as 8 years after high school. (PsycINFO Database Record (c) 2010 APA, all rights reserved)