Substituent effects on absorption spectra of pH indicators: an experimental and computational study of sulfonphthaleine dyes

Sulfonphthaleine dyes are an important class of pH indicators, finding applications in novel (textile) sensors. In this paper, we present a combined experimental and theoretical study to elucidate the halochromic behaviour of a large set of sulfonphthaleine compounds. Starting from an experimental analysis consisting of UV-Vis spectroscopy, the pH region and the absorption wavelengths related to the colour shift are obtained and pK(a) values are derived. The effect of the substituents on the pH region can be traced back to their electron donating/withdrawing properties. Time-Dependent Density Functional Theory (TD-DFT) is able to adequately produce the trend in experimental wavelengths. Proton affinities are used to assess the effect of substituents on the pH region. The combination of theory and experiment is able to give a better understanding of the pH sensitivity; the methodology in this work will be useful in future dye design and is applicable to other dye classes as well. (C) 2013 Elsevier Ltd. All rights reserved

Blonde like me: when self-construals moderate stereotype priming effects on intellectual performance

Stereotype priming can lead to assimilation or contrast effects on behavior. We argue that self-activation is a moderator of both assimilation and contrast effects. To test this hypothesis, in two studies, we activated independent or interdependent self-knowledge before priming participants with the dumb Blonde stereotype or a control category (Study 1) or no prime (Study 2). Participants then answered a knowledge test. Results support our expectations: Participants presented assimilation under interdependence (i.e., underperformance compared to control group) while they presented no assimilation (i.e., comparable performance with control group in Study 1) and contrast (better performance than control group in Study 2) under independence. We discuss implications of these findings in regards of previous research and recent models such as the Active Self Account (Wheeler, DeMarree, & Petty, 2005)

EFFECT OF COMPATIBILITY BETWEEN CONSCIOUS GOAL AND NONCONSCIOUS PRIMING ON PERFORMANCE

Goal pursuit can involve deliberate and conscious processes, but can also occur automatically and nonconsciously, following the priming of specific contents. The way in which priming and conscious goals combine remains unresolved. We investigated the effect of goal-compatible or goal-incompatible priming on the pursuit of a conscious goal. Participants 1) were primed with accuracy-related words or inaccuracy-related words, 2) were given an instruction of accuracy (i.e. a conscious goal), and 3) performed an unskilled motor task. Results indicated that both nonconscious priming and conscious goal influence motor performance. Effects of priming and conscious goal pursuit are additive when contents are compatible and subtractive when they are incompatible

Validité externe et méthode expérimentale

La méthode expérimentale en psychologie est souvent questionnée sous l’angle de la généralisation de ses résultats et de ses modèles (validité externe). Les critères classiques de la validité externe sont exposés. L’accent est mis sur la distinction entre validité externe fondée sur les situations expérimentales et celle fondée sur les processus postulés par un modèle. Les conséquences pour un dialogue entre les disciplines et les méthodes dans le champ de l’information et de la communication sont discutées.In psychology, experimental research is currently mistrusted about the generalization of results and models (external validity). Classical criteria of external validity are reviewed. External validity is either focused on experimental context itself or on process based models. External validity is discussed as a necessary step toward a dialogue between disciplines and methodologies within the field of communication

Polycaprolactone and polycaprolactone/chitosan nanofibres functionalised with the pH-sensitive dye Nitrazine Yellow

A

Raman-modes of index-identified free-standing single-walled carbon nanotubes

Using electron diffraction on free-standing single-walled carbon nanotubes we have determined the structural indices (n,m) of tubes in the diameter range from 1.4 to 3nm. On the same free-standing tubes we have recorded Raman spectra of the tangential modes and the radial breathing mode. For the smaller diameters (1.4-1.7nm) these measurements confirm previously established radial breathing mode frequency versus diameter relations, and would be consistent with the theoretically predicted proportionality to the inverse diameter. However, for extending the relation to larger diameters, either a yet unexplained environmental constant has to be assumed, or the linear relation has to be abandoned.Comment: 4 pages, 4 figures, +additional materials (select PostScript to obtain it

Concerns related to Safety Management of Engineered Nanomaterials in research environment

Since the rise of occupational safety and health research on nanomaterials a lot of progress has been made in generating health effects and exposure data. However, when detailed quantitative risk analysis is in question, more research is needed, especially quantitative measures of workers exposure and standards to categorize toxicity/hazardousness data. In the absence of dose-response relationships and quantitative exposure measurements, control banding (CB) has been widely adopted by OHS community as a pragmatic tool in implementing a risk management strategy based on a precautionary approach. Being in charge of health and safety in a Swiss university, where nanomaterials are largely used and produced, we are also faced with the challenge related to nanomaterials' occupational safety. In this work, we discuss the field application of an in-house risk management methodology similar to CB as well as some other methodologies. The challenges and issues related to the process will be discussed. Since exact data on nanomaterials hazardousness are missing for most of the situations, we deduce that the outcome of the analysis for a particular process is essentially the same with a simple methodology that determines only exposure potential and the one taking into account the hazardousness of ENPs. It is evident that when reliable data on hazardousness factors (as surface chemistry, solubility, carcinogenicity, toxicity etc.) will be available, more differentiation will be possible in determining the risk for different materials. On the protective measures side, all CB methodologies are inclined to overprotection side, only that some of them suggest comprehensive protective/preventive measures and others remain with basic advices. The implementation and control of protective measures in research environment will also be discussed