Fine specificity of anti-V3 antibodies induced in chimpanzees by HIV candidate vaccines

The fine specificity of the anti-V3 antibody responses induced in chimpanzees immunized by various human immunodeficiency type 1 (HIV-1) candidate vaccines and challenged by heterologous strains of HIV-1 was analyzed by enzyme-linked immunosorbent assay (ELISA) and Pepscan epitope mapping. Two chimpanzees immunized with the recombinant canarypox virus ALVAC-HIV (vCP125) expressing gp160MN and boosted with purified gp160MN/LAI alone, then with both immunogens in combination, were not protected against challenge with HIV-1 SF2. Their sera mainly recognized one epitope of the V3 loop, located in the NH2-terminal half. By contrast, immunization of two other chimpanzees with purified gp160MN/LAI and boosting with a synthetic V3MN peptide elicited a strong anti-V3 antibody response with a broader specificity directed against multiple epitopes all along the V3 loop. These chimpanzees were protected against infection by HIV-1 SF2. However, when these two chimpanzees were challenged later with a HIV-1 clade E strain virus, they became infected. We failed to detect any reactivity with the peptide of the ectodomain of gp41 of sera harvested after immunization with the various immunogens or after challenge with HIV-1 SF2 or HIV-1 90CR402. These results demonstrated that anti-V3 antibodies with a restricted fine specificity were induced in chimpanzees immunized with gp160 purified or expressed by recombinant canarypox confirming our previous results obtained in three different species (human, guinea pig and, macaque). In contrast, a boost with the V3 peptide broadened antibody responses, suggesting that the mode of presentation of the V3 loop to the immune system strongly influences the epitope specificity of the resulting antibody response.     

Interpreting the negative mood-helping literature via "mega"-analysis: A contrary view.

"Mega"-analysis was developed by M. Carlson and N. Miller (see record 1987-31249-001) as an extension of traditional meta-analytic procedures for conducting integrative reviews of existing research literatures. One such mega-analysis was conducted by Carlson and Miller to synthesize the literature on the relation between negative mood states and helping. That analysis found no support for a theoretical account (negative state relief) that had been confirmed previously by using various experimental approaches. In an attempt to reconcile the discrepancy, the logic and methods used in Carlson and Miller's mega-analysis of the negative mood-helping literature were examined, and several serious problems were found. These problems are discussed, and data are presented to show that the results of that mega-analysis, and perhaps all mega-analyses, should not be viewed with confidence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A thermodynamic investigation of adsorbate‐adsorbate interactions of carbon dioxide on nanostructured carbons

A thermodynamic study of carbon dioxide adsorption on a zeolite‐templated carbon (ZTC), a superactivated carbon (MSC‐30), and an activated carbon (CNS‐201) was carried out at temperatures from 241 to 478 K and pressures up to 5.5?10⁶ Pa. Excess adsorption isotherms were fitted with generalized Langmuir‐type equations, allowing the isosteric heats of adsorption and adsorbed‐phase heat capacities to be obtained as a function of absolute adsorption. On MSC‐30, a superactivated carbon, the isosteric heat of carbon dioxide adsorption increases with occupancy from 19 to 21 kJ?mol^?1, before decreasing at high loading. This increase is attributed to attractive adsorbate–adsorbate intermolecular interactions as evidenced by the slope and magnitude of the increase in isosteric heat and the adsorbed‐phase heat capacities. An analysis of carbon dioxide adsorption on ZTC indicates a high degree of binding‐site homogeneity. A generalized Law of Corresponding States analysis indicates lower carbon dioxide adsorption than expected. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1026–1033, 2018     

Vibrational thermodynamics of materials

The literature on vibrational thermodynamics of materials is reviewed. The emphasis is on metals and alloys, especially on the progress over the last decade in understanding differences in the vibrational entropy of different alloy phases and phase transformations. Some results on carbides, nitrides, oxides, hydrides and lithium-storage materials are also covered.Principles of harmonic phonons in alloys are organized into thermodynamic models for unmixing and ordering transformations on an Ising lattice, and extended for non-harmonic potentials. Owing to the high accuracy required for the phonon frequencies, quantitative predictions of vibrational entropy with analytical models prove elusive. Accurate tools for such calculations or measurements were challenging for many years, but are more accessible today. Ab initio methods for calculating phonons in solids are summarized. The experimental techniques of calorimetry, inelastic neutron scattering, and inelastic X-ray scattering are explained with enough detail to show the issues of using these methods for investigations of vibrational thermodynamics. The explanations extend to methods of data analysis that affect the accuracy of thermodynamic information.It is sometimes possible to identify the structural and chemical origins of the differences in vibrational entropy of materials, and the number of these assessments is growing. There has been considerable progress in our understanding of the vibrational entropy of mixing in solid solutions, compound formation from pure elements, chemical unmixing of alloys, order-disorder transformations, and martensitic transformations. Systematic trends are available for some of these phase transformations, although more examples are needed, and many results are less reliable at high temperatures. Nanostructures in materials can alter sufficiently the vibrational dynamics to affect thermodynamic stability. Internal stresses in polycrystals of anisotropic materials also contribute to the heat capacity. Lanthanides and actinides show a complex interplay of vibrational, electronic, and magnetic entropy, even at low temperatures.A “quasiharmonic model” is often used to extend the systematics of harmonic phonons to high temperatures by accounting for the effects of thermal expansion against a bulk modulus. Non-harmonic effects beyond the quasiharmonic approximation originate from the interactions of thermally-excited phonons with other phonons, or with the interactions of phonons with electronic excitations. In the classical high temperature limit, the adiabatic electron-phonon coupling can have a surprisingly large effect in metals when temperature causes significant changes in the electron density near the Fermi level. There are useful similarities in how temperature, pressure, and composition alter the conduction electron screening and the interatomic force constants. Phonon-phonon “anharmonic” interactions arise from those non-harmonic parts of the interatomic potential that cannot be accounted for by the quasiharmonic model. Anharmonic shifts in phonon frequency with temperature can be substantial, but trends are not well understood. Anharmonic phonon damping does show systematic trends, however, at least for fcc metals.Trends of vibrational entropy are often justified with atomic properties such as atomic size, electronegativity, electron-to-atom ratio, and mass. Since vibrational entropy originates at the level of electrons in solids, such rules of thumb prove no better than similar rules devised for trends in bonding and structure, and tend to be worse. Fortunately, the required tools for accurate experimental investigations of vibrational entropy have improved dramatically over the past few years, and the required ab initio methods have become more accessible. Steady progress is expected for understanding the phenomena reviewed here, as investigations are performed with the new tools of experiment and theory, sometimes in integrated ways.     

Effects of rewards on children's prosocial motivation: A socialization study.

This study examined the relation between mothers' attitudes/practices regarding the use of rewards and children's susceptibility to the undermining effects of rewards. We assessed the attitudes/practices regarding rewards for 72 mothers and assigned their children to a control condition or to one of four experimental conditions that differed in whether children received rewards for helping and whether children engaged in the helping task or watched other children help. Children were then given an opportunity to help in a nonreward free-choice period. Rewards enhanced helping in the immediate situation. However, rewards undermined children's helping in the free-choice period, but only for children whose mothers felt positive about using rewards. Moreover, mothers who felt more positive about using rewards reported their children to be less prosocial than children of mothers who had less positive attitudes. It was suggested that children's responses to rewards depend in part on their experiences with rewards. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Critical self-reflection and self-perceived altruism: When self-reward fails.

Social learning theory has produced a three-step model of prosocial development: In the young child, prosocial behavior is elicited by material rewards; in the older child, it is elicited also by social rewards; and in the morally mature adult, it is elicited by self-rewards based on an internalized perception of oneself as a kind, caring, altruistic individual. Self-perception theory has complicated this social learning model by demonstrating that once the third step is reached, the continued presence of material and social rewards may undermine intrinsic prosocial motivation based on self-rewards, producing moral regression. We propose a further complication. Critical self-reflection—the desire to know thyself—may introduce a self-deprecating attributional bias that can undermine self-perceived altruism, even following helping for which one receives only intrinsic self-rewards. Two experiments are reported in which we manipulated critical self-reflection on one's reasons for helping. Results indicated that self-reflection undermined self-perceived altruism, especially when the salience of the self-rewards for helping was high. Experiment 2 also provided evidence that, as predicted, this self-reflection effect was most apparent for individuals who valued self-knowledge more highly than concern for others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Religious orientation and overt versus covert racial prejudice.

Tested the prediction that being more religious in one way—as an intrinsic end in itself—would be associated with displaying less racial prejudice when the prejudice was overt, but not when it was covert. It was also predicted that being more religious in another way—as an open-end quest—would be associated with displaying less racial prejudice even when the prejudice was covert. An attributional ambiguity technique developed by M. L. Snyder et al (see record 1981-05489-001) was used. 44 White undergraduates interested in religion chose between sitting with a Black person or a White person to watch a movie. In the overt prejudice condition, the same movie was being shown in both locations; in the covert prejudice condition, 2 movies were being shown. Although not all predicted relations were statistically reliable, the pattern of correlations was consistent with both predictions. An intrinsic orientation to religion was significantly negatively correlated with choosing to sit with the White person in the overt condition, but this correlation was close to zero in the covert condition. Only the quest orientation to religion was significantly negatively correlated with choosing to sit with the White person in the covert condition. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social evaluation and the empathy–altruism hypothesis.

Tested the claim of R. L. Archer et al (see record 1982-05783-001) that empathy leads to increased helping only under socially evaluative circumstances. In Exp I, 22 female undergraduates were led to believe that no one (including the person in need) would ever know if they declined to help. In this situation, which was designed to be devoid of the potential for negative social evaluation for not helping, there was still a positive relationship between self-reported empathic emotion and offering help. In Exp II, empathy (low vs high) and social evaluation (low vs high) were manipulated with 32 Ss. Once again there was a positive relationship between empathy and offering help when the potential for social evaluation was low as well as high. Results of both studies suggest that the motivation to help evoked by empathy is not egoistic motivation to avoid negative social evaluation. Instead, the observed pattern was what would be expected if empathy evokes altruistic motivation to reduce the victim's need. (23 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)