Predicting successful completion of an aftercare program following treatment for alcoholism: The role of dispositional optimism.

In this study we investigated several variables as potential predictors of success in completing a transition program after treatment for alcoholism. Subjects were 54 men who had completed a 30-day treatment program and who were subsequently admitted to a 90-day inpatient aftercare program. The outcome measure was successful completion of this latter program. Predictor variables were dispositional optimism, hassles, uplifts, and several demographic variables. Optimism was positively associated with successful outcome. The simple association between uplifts and outcome also approached significance, but in the opposite to expected direction. Discriminant analyses used both of these variables, as well as age and education level, as predictors of successful outcome. There was no evidence of a role for hassles. Discussion centers on the importance of dispositional optimism as a predictor of successful adaptation in a variety of behavioral domains. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review Paper: Arbuscular Mycorrhiza: Biological, Chemical, and Molecular Aspects

Mycorrhizas are the most important mutualistic symbioses on earth. The most prevalent type are the arbuscular mycorrhizas (AMs) that develop between roots of most terrestrial plants and fungal species of the Zygomycota. The AM fungi are able to grow into the root cortex forming intercellular hyphae from which highly branched structures, arbuscules, originate within cortex cells. The arbuscules are responsible for nutrient exchange between the host and the symbiont, transporting carbohydrates from the plant to the fungus and mineral nutrients, especially phosphate, and water from the fungus to the plant. Plants adapt their phosphate uptake to the interaction with the AM fungus by synthesis of specific phosphate transporters. Colonization of root cells induces dramatic changes in the cytoplasmic organization: vacuole fragmentation, transformation of the plasma membrane to a periarbuscular membrane covering the arbuscule, increase of the cytoplasm volume and numbers of cell organelles, as well as movement of the nucleus into a central position. The plastids form a dense network covering the symbiotic interface. In some of these changes, microtubules are most likely involved. With regard to the molecular crosstalk between the two organisms, a number of phytohormones (cytokinins, abscisic acid, jasmonate) as well as various secondary metabolites have been examined: (i) Jasmonates occur at elevated level, which is accompanied by cell-specific expression of genes involved in jasmonate biosynthesis that might be linked to strong carbohydrate sink function of AM roots and induced defense reactions; (ii) apocarotenoids (derivatives of mycorradicin and glycosylated cyclohexenones) accumulate in most mycorrhizal roots examined so far. Their biosynthesis via the nonmevalonate methylerythritol phosphate (MEP) pathway has been studied resulting in new insights into AM-specific gene expression and biosynthesis of secondary isoprenoids.     

Impact of mutations at different serine residues on the tyrosine kinase activity of the insulin receptor

Insulin binding to its receptor activates a cascade of signaling events which are initiated by tyrosine autophosphorylation of the receptor and activation of the tyrosine kinase activity towards the insulin receptor substrates. In addition to phosphorylation at tyrosine residues a serine phosphorylation of the insulin receptor is observed. Neither the functional significance of serine phosphorylation of the receptor nor the location of relevant regulatory sites has been determined exactly so far. We studied potential functions of serine residues in human insulin receptor (HIR) with respect to its ability to undergo insulin stimulated autophosphorylation. Using site directed mutagenesis of HIR we exchanged serine to alanine at 13 different positions in the HIR beta-subunit. Sites were chosen according to the criteria of known serine phosphorylation sites (1023/25, 1293/94, 1308/09), conserved positions in hIR, hIGF-1 receptor, hIRR, and dIR (962, 994, 1037, 1055, 1074/78, 1168, 1177/78/82, 1202, 1263, 1267). All HIR mutants were expressed in HEK 293 cells and basal and insulin stimulated autophosphorylation were determined. We found that the exchange of serine to alanine at position 994 and at position 1023/25 increased insulin stimulated receptor autophosphorylation significantly (147% +/- 12% and 129% +/- 6% of control, p < 0.01, n = 7), while all other exchanges did not significantly alter insulin stimulated HIR autophosphorylation. The data suggest that the serine residues at position 994 as well as 1023/25 might be part of inhibitory domains of the insulin receptor.     

Amino acid requirements of the nucleocapsid protein of HIV-1 for increasing catalytic activity of a Ki-ras ribozyme in vitro

The nucleocapsid protein NCp7 of HIV-1 is a single-stranded nucleic acid binding protein with several functions such as specific recognition, dimerization and packaging of viral RNA, tRNA annealing to viral RNA and protection against nucleases. Since some of these functions involve annealing and double-stranded RNA-melting activity we applied the nucleocapsid protein to a hammerhead ribozyme specific for the activated Ki-ras mRNA in vitro, which carries at its mutated codon 12 a GUU site. A synthetic ribozyme containing 2'-O-allyl-modified nucleotides and alternatively in vitro transcribed ribozymes were used. At a one to one molar ratio of substrate to ribozyme almost no cleavage is observed at 37 degrees C. Presence of a synthetic nucleocapsid protein significantly increases the catalytic activity of the ribozyme. Kinetic analyses by means of single and multiple turnover reactions performed at various substrate to ribozyme ratios lead to only a slight stimulation of the rate constants for single turnover reactions. The rate constants in multiple turnover reactions, however, are stimulated up to 17-fold by the presence of the nucleocapsid protein. The activating region of the nucleocapsid protein was characterized by a number of mutants. The mutants demonstrate that activation requires both basic amino acid clusters as evidenced by point mutations. Deletion mutants indicate that the second zinc finger is totally dispensable and that replacement of the first zinc finger by a glycine-glycine spacer only slightly reduces the enhancing effect of the nucleocapsid protein on the ribozyme.     

A statistical method for verifying mesh convergence in Monte Carlo simulations with application to fragmentation

A novel method is presented for assessing the convergence of a sequence of statistical distributions generated by direct Monte Carlo sampling. The primary application is to assess the mesh or grid convergence, and possibly divergence, of stochastic outputs from non‐linear continuum systems. Example systems include those from fluid or solid mechanics, particularly those with instabilities and sensitive dependence on initial conditions or system parameters. The convergence assessment is based on demonstrating empirically that a sequence of cumulative distribution functions converges in the L_infty norm. The effect of finite sample sizes is quantified using confidence levels from the Kolmogorov–Smirnov statistic. The statistical method is independent of the underlying distributions. The statistical method is demonstrated using two examples: (1) the logistic map in the chaotic regime, and (2) a fragmenting ductile ring modeled with an explicit‐dynamics finite element code. In the fragmenting ring example the convergence of the distribution describing neck spacing is investigated. The initial yield strength is treated as a random field. Two different random fields are considered, one with spatial correlation and the other without. Both cases converged, albeit to different distributions. The case with spatial correlation exhibited a significantly higher convergence rate compared with the one without spatial correlation. Copyright © 2011 John Wiley & Sons, Ltd.     

Old is old is old?

We examined potential differences between two matched subgroups of elderly men: young–old (65–74 years of age; n?=?56). Subjects were fairly healthy men from community agencies, who were interviewed and tested on a number of characteristics involving personality, mood, attitudes, and behaviors. Although t tests and correlations indicated some differences between the groups, the overall findings underlined their similarity on the vast majority of variables scrutinized. The crucial base for enhancing understanding in gerontology should not only focus on the age-advancing senescent person but on the whole individual. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exact results on ferromagnetism in correlated electron systems

Exact results, both old and new, on the stability of saturated ferromagneiism in the Hubbard model and its extensions are discussed. For the Hubbard model with all nearest-neighbor interactions a new set of rigorous criteria, valid at half filling, is derived and a generalization of Nagaoka's theorem to finite interactions is presented. Of all coupling parameters only the on-site and the exchange interaction are found to be essential. At strong coupling comparison with the effective t — J model is made. Further extensions, e.g. to the band-degenerate case, are discussed.     

"Mood contagion": The automatic transfer of mood between persons.

The current studies aimed to find out whether a nonintentional form of mood contagion exists and which mechanisms can account for it. In these experiments participants who expected to be tested for text comprehension listened to an affectively neutral speech that was spoken in a slightly sad or happy voice. The authors found that (a) the emotional expression induced a congruent mood state in the listeners, (b) inferential accounts to emotional sharing were not easily reconciled with the findings, (c) different affective experiences emerged from intentional and nonintentional forms of emotional sharing, and (d) findings suggest that a perception–behavior link (T. L. Chartrand & J. A. Bargh, 1999) can account for these findings, because participants who were required to repeat the philosophical speech spontaneously imitated the target person's vocal expression of emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Use of Sphere Indentation Experiments to Characterize Ceramic Damage Models

Sphere impact experiments are used to calibrate and validate ceramic models that include statistical variability and/or scale effects in strength and toughness parameters. These dynamic experiments supplement traditional characterization experiments such as tension, triaxial compression, Brazilian, and plate impact, which are commonly used for ceramic model calibration. The fractured ceramic specimens are analyzed using sectioning, X-ray computed tomography, microscopy, and other techniques. These experimental observations indicate that a predictive material model must incorporate a standard deviation in strength that varies with the nature of the loading. Methods of using the spherical indentation data to calibrate a statistical damage model are presented in which it is assumed that variability in strength is tied to microscale stress concentrations associated with microscale heterogeneity.     

Resistivity studies on different variants of κ-(BEDT-TTF)2Cu[N(CN)2]Br: Evidence for Disorder and/or defect-induced inelastic scattering contributions

Comparative resistivity measurements have been performed on differently prepared κ-(ET)₂Cu[N(CN)₂]Br single crystals. While the T_c values and their shifts under hydrostatic pressure are found to be sample independent, the resistivity profiles, especially around the resistivity hump at 90 K and the low-temperature ρ ∝ T² behavior, show striking sample-to-sample variations. In the absence of significant differences in the crystals’ structural parameters and chemical compositions, as proved by high-resolution X-ray and electron-probe-microanalysis studies, these results indicate that real structure phenomena, i.e. disorder and/or defects, strongly affect the inelastic scattering in these molecular conductors.