Synthesis of biocompatible, mesoporous Fe(3)O(4) nano/microspheres with large surface area for magnetic resonance imaging and therapeutic applications

This article reports the fabrication of mesoporous Fe(3)O(4) nano/microspheres with a high surface area value (163 m(2)/g, Brunauer-Emmett-Teller) and demonstrates their use for drug loading, release, and magnetic resonance imaging (MRI). These monodispersed, mesoporous Fe(3)O(4) nano/microspheres with controllable average sizes ranging from 50 to 200 nm were synthesized using a Fe(3)O(4)/poly(acrylic acid) hybrid sphere template and subsequent silica shell formation and removal. We found that the SiO(2) coating is a crucial step for the successful synthesis of uniform mesoporous Fe(3)O(4) nano/microspheres. The as-synthesized mesoporous Fe(3)O(4) nanospheres show a high magnetic saturation value (M(s) = 48.6 emu/g) and could be used as MRI contrast agents (r(2) = 36.3 s(-1) mM(-1)). Trypan blue exclusion and MTT assay (see Supporting Information ) cytotoxicity analyses of the nanospheres based on HepG2 and MDCK cells showed that the products were biocompatible, with a lower toxicity than lipofectamine (positive control). Hydrophilic ibuprofen and hydrophobic zinc(II) phthalocyanine drug loading into mesoporous Fe(3)O(4) nanospheres and selected release experiments were successfully achieved. The potential use of mesoporous Fe(3)O(4) nanospheres in biomedical applications, in light of the nano/microspheres' efficient drug loading and release, MRI, and low cytotoxicity, has been demonstrated. It is envisaged that mesoporous Fe(3)O(4) nanospheres can be used as drug carriers and MRI contrast agents for the reticuloendothelial system; they can also be delivered locally, such as via a selective catheter.     

Nickel-boron nanolayer evolution on boron carbide particle surfaces during thermal treatment

This study is focused on reduction of Ni₂O₃ and B₂O₃ in the Ni-B nanolayer on B₄C particle surfaces and understanding of the nanolayer composition and morphology changes. Initially, the nanolayer contains Ni₂O₃, B₂O₃, and amorphous boron. After 400 °C thermal treatment in a H₂-Ar atmosphere, Ni₂O₃ is reduced to nickel; the nanolayer morphology is maintained and the coated particles demonstrate magnetism. As the thermal treatment temperature is increased to 550 °C, B₂O₃ is reduced to boron, which reacts with nickel and forms Ni₂B. Simultaneously, the nanolayer evolves into nanoparticles. Thermal treatment temperature increase to 700-900 °C only causes Ni₂B particle growth but does not fundamentally change the composition or phase.     

Narcissistic injury and its relationship to early trauma, early resources, and adjustment to college.

Used structural equation modeling to test the hypothesized model that the effects of early trauma are buffered by early resources and that these variables, in turn, affect psychological damage and subsequent adjustment. In addition, the utility of the Narcissistic Injury Scale (NIS; S. L. Slyter, 1991), an operationalization of A. Miller's (1981) construct of narcissistic injury, was assessed. 250 students completed questionnaires measuring past trauma, early resources, psychological damage, and adaptation to college. Results supported the reliability and validity of the NIS. Structural equation analyses resulted in a final model with a very good overall fit. The path linking early trauma to psychological damage and then subsequent adjustment accounted for the most variance. The hypothesized buffering effects of early resources were not supported. Counseling and research applications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Children's face recognition memory: More evidence for the cross-race effect.

It is well established that own-race faces are recognized more accurately than cross-race faces. However, there are mixed results regarding the developmental consistency of the cross-race effect. White and Black kindergarten children, 3rd graders, and young adults viewed a Black and a White target individual. One day later, recognition memory for each target was tested with a 6-person lineup. The interaction of race of participant by race of target face on Ag scores was significant, demonstrating an overall cross-race effect. The 2nd-order interaction with age did not approach significance: for each age group, own-race identification was more accurate than cross-race identification. The age consistency of the cross-race effect in light of the significant main effect of age suggests quantitative but not qualitative differences in face memory processing at various ages. For children, as well as adults, own-race faces are recognized more accurately than cross-race faces. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Knowledge construction in the learner-centered classroom.

In this study, the author describes the nature and occurrence of knowledge-construction links (KCLs) in 3 6th-grade classrooms that varied in degree of learner centeredness. KCLs are operationalized as prior learning that students bring to their current classroom experiences and include school and nonschool experiences. They are hypothesized to facilitate a knowledge-construction process that values prior learning. In the more learner-centered classroom, KCLs occurred in conjunction with open and divergent dialogue, positive reactions to students' use of prior learning, and opportunities within the classroom that allowed students to gain new experiences on which they could draw in further knowledge-construction efforts. In contrast, KCLs were ignored or viewed as inappropriate in the least learner-centered classroom, dialogue about content was convergent, and performance goals were the norm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptions of intelligence in leaderless groups: The dynamic effects of shyness and acquaintance.

Perceptions of intelligence were investigated in 2 longitudinal studies of leaderless discussion groups (LDGs). In Study 1 (N?=?87), students completed trait-shyness questionnaires and met 7 times in groups of 4–5. After Meetings 2 and 7, participants rated all group members on state shyness and intelligence. Trait-shy participants were initially judged to be less intelligent on both self and peer ratings. At Time 2, however, trait-shy participants were no longer derogated by peers. Study 2 (N?=?103) replicated the same pattern of shy derogation while demonstrating no actual relation between IQ and trait shyness. Again, trait-shy derogation disappeared by Time 2, but state-shy derogation continued. The state shy were now the low-lQ participants, who had begun to talk less. Thus, the bias against quiet individuals, originally inappropriate, gradually became a valid cue for low intelligence. Results were traced to overlapping cues for intelligence and shyness in LDGs. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Parental history of hypertension and screening attendance: Effects of wellness appeal versus threat appeal.

226 undergraduates with and without a hypertensive parent were given printed material about hypertension and the importance of early detection framed in either a wellness or illness-threat format. The major dependent measure was attendance at a blood pressure screening during the week following the experimental session. Results show that parental history (PH) Ss were more than twice as likely to attend the screening when given a wellness message in comparison to threat. In the threat condition, PH Ss also reported that hypertension was less preventable in comparison with Ss without a hypertensive parent. Reported likelihood of developing hypertension was inversely related to subsequent screening attendance among PH Ss only. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of cue-controlled desensitization, rational restructuring, and a credible placebo in the treatment of speech anxiety.

Compared the efficacy of cue-controlled desensitization and systematic rational restructuring with a placebo method (subconscious reconditioning) and a waiting-list control in reducing public speaking and nontargeted anxieties. Ss were 57 undergraduates. Cue-controlled desensitization was generally more effective than the other groups in reducing subjective speech anxiety. In general, no differential between-groups changes emerged on treatment generalization or behavioral speech anxiety measures. Although rational restructuring produced few significant pre–post changes, it did lead to significant gains on several measures by follow-up. On treatment credibility ratings, the placebo was initially perceived as less credible than rational restructuring, but this difference diminished by the middle of treatment. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)