Glass Formation and Polyamorphism in Rare-Earth Oxide–Aluminum Oxide Compositions

We report formation of single- and two-phase glasses from rare-earth oxide–alumina materials. Liquids with the Y₃Al₅O₁₂ and Er₃Al₅O₁₂ compositions underwent a liquid–liquid phase transition which resulted in glasses with a cloudy appearance due to spheroids of one glass in a matrix of a second glass. The two glasses were isocompositional within the limits of experimental error. Clear, brilliant, single-phase glasses were obtained from La₃Al₅O₁₂, ErLaYAl₅O₁₂, and compositions containing ≥5 mol% La₂O₃ substituted for the other rare-earth oxides. Formation of two glasses is attributed to nucleation and growth of the second liquid at a temperature below the equilibrium liquid–liquid transition temperature. Addition of lanthanum depresses the phase transition temperature below the glass transition temperature and the liquid–liquid phase transition is not observed. The results are discussed in the context of first-order liquid–liquid phase transitions (polyamorphism) and formation of single-phase glass from liquids that contain a high proportion of 4-coordinate aluminum ions.     

Reduction of fumonisin B₁ in corn grits by twin-screw extrusion

Abstract: This study was designed to investigate the fate of fumonisins in flaking corn grits during twin‐screw extrusion by measuring fumonisin B₁ (FB₁) and its analogs with a mass balance approach. Food grade corn grits and 2 batches of grits contaminated with FB₁ at 10 and 50 μg/g by Fusarium verticillioides M‐2552 were processed with or without glucose supplementation (10%, w/w) with a twin‐screw extruder. Extrusion reduced FB₁ in contaminated grits by 64% to 72% without glucose and 89% to 94% with added glucose. In addition, extrusion alone resulted in 26% to 73% reduction in the levels of fumonisin B₂ and fumonisin B₃, while levels of both mycotoxins were reduced by >89% in extruded corn grits containing 10% glucose. Mass balance analysis showed that 38% to 46% of the FB₁ species detected in corn extruded with glucose was N‐(deoxy‐D‐fructos‐1‐yl)‐FB₁, while 23% to 37% of FB₁ species detected in extruded corn grits with and without added glucose was bound to the matrix. It was also found that the hydrolyzed form of FB₁ was a minor species in extruded corn grits with or without added glucose, representing <15% of the total FB₁ species present. Less than 46% of FB₁ originally present in corn grits could be detected in the fumonisin analogues measured in this study. Research is needed to identify the reaction products resulting from extrusion processing of fumonisin‐contaminated corn products. Practical Application: Twin‐screw extrusion is widely used in food industry for its versatility. This technology may reduce the level of fumonisins in corn particularly with added glucose.     

Thinking about thinking in therapy: An examination of clients' understanding of their therapists' intentions.

Two therapists each provided 2 clients time-limited (10 sessions each) therapies. These were examined to discover relations between (a) clients' understanding of therapists' intentions and episode level outcome, (b) similarities and differences between the participants' valuing of different intentions, and (c) shifts in intentions valued from the beginning to the terminal phases of therapy. By using therapists' segmentation of sessions into episodes and a computerized Counselor Intention List, some positive relations between clients' understanding of counselor intention and episode impact were documented. Differences were found between therapists' and clients' valued intentions as were systematic shifts on valued intentions from beginning to end phases of therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning effects in the block design task: A stimulus parameter-based approach.

Learning effects were assessed for the block design (BD) task, on the basis of variation in 2 stimulus parameters: perceptual cohesiveness (PC) and set size uncertainty (U). Thirty-one nonclinical undergraduate students (19 female) each completed 3 designs for each of 4 varied sets of the stimulus parameters (high-PC/high-U, high-PC/low-U, low-PC/high-U, and low-PC/low-U), ordered randomly within a larger set of designs with mixed stimulus characteristics. Regression analyses revealed significant, although modest, learning effects in all conditions. Negative-logarithmic learning slopes (growth factors) were greatest for high-U/high-PC designs and smallest for low-U/low-PC designs. Comparison of these slopes with known Wechsler Adult Intelligence Scale (3rd ed.; D. Wechsler, 1997; and 4th ed.; D. Wechsler, 2008) BD subtest gain scores demonstrated that presenting novel test items matched on stimulus parameters in multiple administrations reduced learning effects compared with the repeated use of the same test items. The results suggest that repeated administration of novel test items of the BD subtest, matched for PC and U, would result in more accurate assessments of changes in examinees’ abilities over time than would the use of the same items. Difficulties inherent in implementing this method are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multilevel modeling and school psychology: A review and practical example.

The purpose of this article is to provide an overview of the state of multilevel modeling in the field of school psychology. The authors provide a systematic assessment of published research of multilevel modeling studies in 5 journals devoted to the research and practice of school psychology. In addition, a practical example from the nationally representative Early Childhood Longitudinal Study—Kindergarten Cohort (ECLS–K) is presented to help school psychologists become familiar with the basic terminology and procedures used in multilevel modeling studies. Implications for statistical reform and future research practices are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

“Are You Kidding Me?”: The Role of Nonverbal Cues in the Verbal Accounting Process

This article reports on an investigation of 78 interactions for the messages sent by nonverbal cues in account sequences. Account elicitations and evaluations were rated based on vocal and facial behaviors communicating five messages: (a) positive or negative affect, (b) certainty or uncertainty, (c) understanding or confusion, (d) agreement or disagreement, and (e) belief or disbelief. We also coded the accounters' discourse that followed elicitations and evaluations to investigate the relationship between nonverbal messages and the account forms used by the teller. Our results showed that, even when controlling for what a person said, the messages sent by nonverbal cues could all predict subsequent account forms, although not always in the way expected. These results help our argument that nonverbal cues may be an important part of moving through account sequences, both on their own and when combined with verbal utterances.     

A spatially and chemically defined platform for the uniform growth of human pluripotent stem cells

We report the design of a chemically defined platform engineered for the culture of human pluripotent stem cells (hPSCs) that supports the long-term maintenance of self-renewing hPSC populations in a more uniform manner than standard culture systems. Microcontact printing (μCP) of alkanethiol self-assembled monolayers (SAMs) was used to spatially direct hPSC adherence. This technique not only establishes control over hPSC colony size and shape but also preserves genetic stability and provides unprecedented uniformity in the pluripotency of hPSC populations that is quantitatively assessed in the present study.