Energetics of Defect Fluorite and Pyrochlore Phases in Lanthanum and Gadolinium Hafnates

Aerodynamic levitation combined with laser heating was used to prepare melts in the HfO₂–La₂O₃ (–Gd₂O₃) systems. All melts crystallized upon quenching in oxygen. Hf₂La₂O₇ pyrochlore and Gd_0.5Hf_0.5O_1.75 fluorite phases were identified. Gd_0.5Hf_0.5O_1.75 fluorite was transformed into the pyrochlore structure by annealing at 1450°C. Pyrochlore that crystallized from HfO₂- La₂O₃ melts contained 31.6–34.2 mol% La₂O₃. The unit cell parameter increased linearly with La content from 10.736 to 10.789 Å. Drop solution calorimetric experiments were performed in 3Na₂O·4MoO₃ melt at 702°C. The enthalpies of formation from the oxides for pyrochlore phases are −107.0±5.0 kJ/mol for Hf₂La₂O₇ and −48.8±4.7 kJ/mol for Hf₂Gd₂O₇. The enthalpy of the pyrochlore–fluorite phase transition in Hf₂Gd₂O₇ is 23.6±3.1 kJ/mol.     

The Relation Between Television Exposure and Theory of Mind Among Preschoolers

This study explored the relation between preschoolers' television exposure and one important indicator of cognitive processing called theory of mind (ToM). A total of 107 preschoolers and their parents provided data on the preschoolers' television exposure (including both intentional viewing and exposure via background television), parent–child discussion of television, and preschoolers' ToM. The results indicated that preschoolers who were exposed to more background television and who had a television in their bedroom performed more poorly on ToM assessments compared with other children. Parent–child discussion of television was positively related to ToM performance, however. These results have implications for how we understand the effects of television on preschoolers.     

Relation of task switching to speed, age, and fluid intelligence.

Two studies were conducted to investigate whether a meaningful task-switching construct could be identified and, if so, to determine how it was related to measures of higher order cognition and to adult age. Both studies revealed that measures of task switching were moderately correlated across different combinations of tasks and that a switching construct could be distinguished from a construct reflecting processing speed. The results of the 2nd study revealed that although the task-switching construct was related to age and to measures of episodic memory, inductive reasoning, and spatial visualization, most of the relations between the switching construct and both age and other measures of cognition were shared with other variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Arsenic transformation and mobilization from minerals by the arsenite oxidizing strain WAO

Analysis of arsenic concentrations in New Jersey well water from the Newark Basin showed up to 15% of the wells exceed 10 microg L(-1), with a maximum of 215 microg L(-1). In some geologic settings in the basin, this mobile arsenic could be from the weathering of pyrite (FeS2) found in black shale that contains up to 4% arsenic by weight. We hypothesized that under oxic conditions at circumneutral pH, the microbially mediated oxidation of sulfide in the pyrite lattice would lead to the release of pyrite-bound arsenic. Moreover, the oxidation of aqueous As(III) to As(V) by aerobic microorganisms could further enhance arsenic mobilization from the solid phase. Enrichment cultures under aerobic, As(III)-oxidizing conditions were established under circumneutral pH with weathered black shale from the Newark Basin as the inoculum source. Strain WAO, an autotrophic inorganic-sulfur and As(III)-oxidizer, was isolated and phylogenetically and physiologically characterized. Arsenic mobilization studies from arsenopyrite (FeAsS) mineral, conducted with strain WAO at circumneutral pH, showed microbially enhanced mobilization of arsenic and complete oxidation of released arsenic and sulfur to stoichiometric amounts of arsenate and sulfate. In addition, WAO preferentially colonized pyrite on the surface of arsenic-bearing, black shale thick sections. These findings support the hypothesis that microorganisms can directly mobilize and transform arsenic bound in mineral form at circumneutral pH and suggest that the microbial mobilization of arsenic into groundwater may be important in other arsenic-impacted aquifers.     

Insights from NMR Spectroscopy into the Conformational Properties of Man‐9 and Its Recognition by Two HIV Binding Proteins

Man₉GlcNAc₂ (Man‐9) present at the surface of HIV makes up the binding sites of several HIV‐neutralizing agents and the mammalian lectin DC‐SIGN, which is involved in cellular immunity and trans‐infections. We describe the conformational properties of Man‐9 in its free state and when bound by the HIV entry‐inhibitor protein microvirin (MVN), and define the minimum epitopes of both MVN and DC‐SIGN by using NMR spectroscopy. To facilitate the implementation of 3D ¹³C‐edited spectra to deconvolute spectral overlap and to determine the solution structure of Man‐9, we developed a robust expression system for the production of ¹³C,¹⁵N‐labeled glycans in mammalian cells. The studies reveal that Man‐9 interacts with HIV‐binding proteins through distinct epitopes and adopts diverse conformations in the bound state. In combination with molecular dynamics simulations we observed receptor‐bound conformations to be sampled by Man‐9 in the free state, thus suggesting a conformational selection mechanism for diverse recognition.     

Examining the relationship between the Big Five,Grit and avoidance of automated communication scales in adults 40–65

Automated communication technologies (ACTs) have largely become commonplace in the day to day life. Although these technologies are widely used, there is a not insubstantial proportion of the population that prefers to avoid contact with ACTs. Recently, a scale was developed to assess dispositional avoidance of automated communication technologies. The current study provides validation of the scale in an older adult population and demonstrates that the avoidance of automated communication scale can be discriminated from personality measures, including the Big Five and Grit, and is predictive of avoidance of ACTs.     

The perceived effectiveness of Christian and secular graduate training programs in preparing Christian psychologists to deal with experiences of sexual attraction.

Most psychologists experience feelings of sexual attraction toward clients, and for some Christian therapists this situation can be further complicated by their tendency to deny such sexual attraction. How effective are graduate training programs in teaching Christian psychologists to manage feelings of sexual attraction in professional contexts? In this survey, 258 Christian psychologists answered questions regarding their graduate training. A positive training environment was related to healthy coping responses in managing feelings of sexual attraction, and graduates of explicitly Christian training programs reported greater satisfaction with training conditions than graduates of secular programs. Those involved in training professional psychologists should consider the general training environment in addition to specific course work about managing feelings of sexual attraction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The characterization of protein post-translational modifications by mass spectrometry

Most biological processes are regulated by post-translational modifications of proteins, and conditions that disrupt the regulation of such events can lead to disease. In the past decade, the identification and characterization of covalent modifications have been driven by advances in mass spectrometry. Here, we discuss current mass spectrometric and proteomic approaches for the identification of proteins and their covalent modifications, and we highlight high-throughput strategies for comprehensive analysis of cell proteomes.