College students' judgements and perceptions of persons with AIDS from different risk groups.

In this analog study, 104 female and 75 male undergraduate students in the United States read 1 of 8 vignettes that described a person who had just received positive HIV antigen results. The vignettes were identical except for the sex of the person described and his or her risk-group membership (gay, heterosexual, injection-drug user, or hemophiliac). After reading the vignette, the participants completed questionnaires assessing (a) responsibility, blame, and personality characteristics of the person described in the vignette; and (b) their own homophobia and knowledge about AIDS. Results revealed that homophobia was a significant covariate that affected participants' perceptions of the person in the vignette. With homophobia as a covariate, the hemophiliac was judged the least harshly, followed by the heterosexual person, the gay person, and the injection-drug user. No gender differences were revealed. The injection-drug user was evaluated the most negatively on the personality characteristics; the other 3 groups were rated similarly. Analyses without homophobia as a covariate revealed significant gender differences, suggesting that prior research findings of gender differences on perceptions of persons with AIDS may be attributable more to differential levels of homophobia than to gender of the rater.

alpha- and beta-cyclodextrin rotaxanes of mu-bis(4-pyridyl)bis[pentacyanoferrate(II)] complexes.

The kinetics and mechanism of the self-assemblies of alpha- and beta-cyclodextrin (CD) [2]rotaxanes, [(NC)5Fe-[pyRpy.CD]Fe(CN)5]6-, containing pentacyanoferrate(II)-stoppered 4,4'-bis(pyridyl) threads pyRpy (R = -CH = CH-, -N=N-, -CH=N-N=CH-, and -C(CH3)=N-N=C(CH3)-) have been investigated in aqueous solution by using visible and 1H NMR spectroscopy. The rotaxanes may be formed rapidly by the addition of the [Fe(CN)5OH2]3- ion to the CD-included pyRpy thread or slowly by the addition of an excess of CD to the dimeric [(NC)5Fe(pyRpy)Fe(CN)5]6- complex. In the latter method, the mechanism involves a rate-determining dissociation of a [Fe(CN)5]3- center to form the monomeric complex, which subsequently includes the coordinated pyRpy in the CD cavity to yield the semirotaxane, which is rapidly recomplexed by the [Fe(CN)5OH2]3- ion, generating the [2]rotaxane. Rate and activation parameters and CD inclusion stability constants have been determined for the ligand substitution reactions involving the formations and dissociations of the semirotaxanes and rotaxanes. The extents of the decreases in the formation (kf) and dissociation (kd) rate constants upon CD inclusions of the free and coordinated ligands, respectively, are related to the natures of the CD hosts and the R linkage on the pyRpy guests. The semirotaxanes and rotaxanes exhibit significant bathochromic shifts in their visible MLCT transitions compared with the corresponding monomeric and dimeric iron complexes. A correlation between the extent of the decrease in kd and the change in the MLCT energy upon alpha-CD inclusions of [Fe(CN)5L]3-, where L is an aromatic N-heterocyclic 4-Rpy or pyRpy ligand, has been observed.