Hydroxytelechelic hydrocarbon copolymers with high aging resistance for elastomeric materials

Dihydroxytelechelic copolyalkenamers were prepared via metathetical polymerization of cyclic olefins (cyclooctadiene, cyclooctene and cyclododecene) in presence of first generation Grubbs catalyst and butene diacetate as functionalizing chain transfer agent in order to study their aging resistance. The influence of compositions and molar masses of the copolyalkenamers were investigated in terms of thermo‐mechanical properties. Increasing chains length or the proportion of polycyclooctadiene allow to get non‐cristalline polymers. Low T_g materials (between ?78°C and ?108°C) were prepared. The resistance towards oxidation of the different copolyalkenamers was carried out using a viscosity measurement method. A critical time, corresponding to a brutal increase of the apparent viscosity, was related to degradation of the polymers and was shown to be dependent on the Csp² proportion in the structure. The absence of vinylic units and the decrease of the double bonds content within the copolymers were proved to enhance the stability of the copolyalkenamers towards aging resistance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Executive function and theory of mind: Predictive relations from ages 2 to 4.

Despite robust associations between children's theory of mind (ToM) and executive function (EF) skills, longitudinal studies examining this association remain scarce. In a socially diverse sample of 122 children (seen at ages 2, 3, and 4), this study examined (a) developmental stability of associations between ToM, EF, verbal ability, and social disadvantage; (b) continuity and change in ToM and EF; and (c) predictive relations between ToM and EF. Verbal ability and social disadvantage independently predicted changes in EF (but not ToM). Task scores improved with age and showed stable individual differences. The authors examined predictive relations between ToM and EF using partial correlations (controlling for age and verbal ability) and hierarchical regressions (that also controlled for social disadvantage and initial ToM and EF). The findings provide only partial support for the view that ToM is a prerequisite for EF but stronger support for the proposal that EF facilitates children's performance on ToM tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluating the Costs and Benefits of Salt Management Strategies at Mine Sites Using a Systems Model

Unprecedented expansion of coal mining in Australia is occurring within the context of a severe ongoing drought. This has induced more companies to adopt improved water management strategies, such as water reuse. A direct consequence of this is an increase in the salt concentration of the water, which affects in turn the efficiency of the coal preparation processes, the quality of the coal product, and the level of required equipment maintenance. There are three strategies that can be adopted with respect to salt management: accept the elevated salt concentrations and increase spending on equipment maintenance; remove the salt by desalination; and dilute the salt by importing more water. A tool is required to predict the salt concentrations arising from water reuse and to simulate the impact of potential management strategies. This paper presents a systems approach to the modelling of coupled mine site water and salt balances to assist with understanding the implications of implementing desalination or dilution and with assessing the costs and benefits of each option.     

The Role of Feedback Information for Calibration and Attunement in Perceiving Length by Dynamic Touch.

Two processes have been hypothesized to underlie improvement in perception: attunement and calibration. These processes were examined in a dynamic touch paradigm in which participants were asked to report the lengths of unseen, wielded rods differing in length, diameter, and material. Two experiments addressed whether feedback informs about the need for reattunement and recalibration. Feedback indicating actual length induced both recalibration and reattunement. Recalibration did not occur when feedback indicated only whether 2 rods were of the same length or of different lengths. Such feedback, however, did induce reattunement. These results suggest that attunement and calibration are dissociable processes and that feedback informs which is needed. The observed change in variable use has implications also for research on what mechanical variables underlie length perception by dynamic touch. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical and sublexical translation of spelling to sound: Strategic anticipation of lexical status.

Two experiments on oral reading of single words compared naming performance in pure blocks of nonwords or exception words with performance in blocks of randomly mixed nonwords and exception words. Ss named exception words faster and made fewer regularization errors when they were not also prepared for nonwords. These data suggest Ss inhibit or ignore the computation of assembled phonology when only exception words are expected. Ss named nonwords faster, but no more accurately, when low-frequency exception words were not also anticipated. Thus, Ss' readiness to execute assembled phonology appears to be adjusted in relation to the likely time course of retrieval of learned pronunciations, when the latter must be attended to. This evidence for strategic dissociation between sublexical and lexical translation is discussed in relation to current models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimisation of extraction of phenolics and antioxidants from black currant leaves and buds and of stability during storage

Health benefits of a diet rich in fruits and vegetables are attributed in part to their contents of phenolics and other antioxidant compounds. In this research, the extraction of phenolics and antioxidant compounds from black currant was optimised for different plant organs. The extraction solvent affected yield: aqueous acetone was better than methanol and acetate or glycine buffer. In aqueous buffer, maximum yields of total phenolics and antioxidant activities were obtained at pH 3. Extraction from lyophilised materials yielded extracts with higher phenolic contents and antioxidant activities.     

Process analyses of the behavior of very young children in delay tasks.

Conducted 2 studies to examine the behavior of young children in tasks demanding self-control. In Study 1, 27 2-yr-olds were observed in 1 task. Behavior during the task was described using a 10-category coding system, and proportion scores derived from the 10-category coding system were correlated with total time in the task. Results show that 5 of the 10 correlations were significant. Behaviors bringing the goals into attention were negatively correlated with total delay time, whereas behaviors taking the goal out of attention tended to be positively associated with delay. In Study 2, 82 children (aged 24–36 mo) were observed in 3 delay tasks. The behavioral strategy studied was directing attention away from the goal object during delay periods. Significant effects were found for age and task type. When the sample was divided into shorter vs longer waiters, it was found that the longer waiters looked away from the goal for a larger proportion of the time. It is suggested that young children use implicit strategies for controlling their behavior in the face of a social demand. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Make believe and reality: Explorations of the imaginary realm.

Preschool children's ability to distinguish between pretense and reality was examined in 2 studies that adopted a modified version of the design used by P. L. Harris, E. Brown, M. Marriott, S. Whittall, and S. Harmer (1991) in which a pretend creature is assumed to hide inside a box. In Study 1, 19 4-year-olds participated in test conditions that closely followed Harris et al.'s procedures. In Study 2, 75 3- and 4-year-olds were randomly assigned to 1 of 4 emotionally colored pretense play scenarios that included 4 test conditions: an imaginary creature, invented by the adult or the child, whose affective value was either positive or negative. The results of both studies do not support Harris et al.'s interpretation of their data in terms of a breakdown of the distinction between pretense and reality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification in the rat neurotensin receptor of amino-acid residues critical for the binding of neurotensin

In order to identify charged amino-acid residues of the cloned rat brain neurotensin (NT) receptor (NTR) that are critical for NT binding, we performed site-directed mutagenesis on the cDNA encoding this protein, followed by transient expression into mammalian COS-7 cells and in Xenopus laevis oocytes. Point substitutions of charged residues in the N-terminal part and in the 2nd and 3rd extracellular loop of the receptor either did not affect (125)I-Tyr3-NT binding or resulted in a decrease in binding affinity by a factor of 2-3. Mutations of amino acids Asp113 in the second transmembrane domain (TM) and of Arg149 or Asp150 in TM III yielded receptors that bound NT as efficiently as the native receptor. By contrast, replacement of the Asp139 residue in the 1st extracellular loop, or of Arg143 or Arg327-Arg328 residues at the top of TM III and in TM VI, respectively, completely abolished ligand binding. Confocal and EM immunocytochemical studies of the expression of these affected receptors, tagged with the C-terminal sequence of the vesicular stomatitis virus glycoprotein (VSV-G), indicated that this loss of binding was not due to altered receptor expression or to their improper insertion into the plasma membrane. When these mutated forms of neurotensin receptor were expressed into Xenopus oocytes, Asp139-Gly- and Arg143-Gly-modified receptors remained functional in spite of a lowered response to NT whereas the Arg327-Arg328 mutant form was totally insensitive to NT at concentrations up to 10 microM. In the case of the Arg327-Arg328 mutation, the observed insensibility to NT could be the result of a drastic conformational alteration of this mutant protein. By contrast, it would appear that Asp139 and Arg143 residues located in the first extracellular loop of the receptor may be directly involved in the interaction of the receptor with neurotensin.