"Psychology in extremis: Preventing problems of professional competence in dangerous practice settings": Correction to Johnson et al. (2011).

Reports an error in "Psychology in extremis: Preventing problems of professional competence in dangerous practice settings" by W. Brad Johnson, Shannon J. Johnson, Glenn R. Sullivan, Bruce Bongar, Laurence Miller and Morgan T. Sammons (Professional Psychology: Research and Practice, 2011[Feb], Vol 42[1], 94-104). The title and authors for the first section of the article, beginning of the first column on page 95, were inadvertently omitted. The section should have begun with the following: “In Extremis Practice: Ensuring Competence During and After Deployment to a Combat Zone,” by W. Brad Johnson and Shannon J. Johnson. (The following abstract of the original article appeared in record 2011-04544-013.) When a psychologist provides services in a dangerous context—a work setting defined by persistent threat to the psychologist's own personal safety and well-being—the psychologist is said to practice in extremis. Psychologists who routinely function in extremis, such as those in correctional, disaster response, military, and police psychology—among other specialties—may be at increased risk for troubling experiences such as direct or vicarious traumatization, compassion fatigue, and empathy failure. Over time, in extremis experiences may contribute to decrements in professional competence. When psychologists become aware of personal problems that interfere with their work, they must take steps to ameliorate the problem while protecting consumers. In this Focus on Ethics, we discuss the difficulty inherent in self-identifying and correcting problems of professional competence when working in a high-threat environment. Three expert commentaries further elucidate in extremis competency concerns from the perspective of disaster response, police, and military psychology. The authors provide numerous recommendations for helping psychologists to ensure ongoing competence in in extremis jobs. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Controlling reaction rate of phase transfer hydrogenation of acetophenone by application of low external electric field

The controllable mass transfer and reaction rate for phase transfer hydrogenation of acetophenone across a well-defined boundary were investigated. The effect of solvent was found important and 1-butanol exhibited the best performance among the five investigated homologous alcohol solvents, consistent with its higher solubility in water and greater dielectric constant. Initial reaction rates increased with increasing electric potential, consistent with enhanced mass transfer across the aqueous/organic boundary. At longer reaction times, deactivation was apparent. It correlated with increasing voltage and is ascribed to lower equilibrium concentration of reactive species at the interface. External control over reaction rate was demonstrated by switching the applied electric potential over the course of the reaction. Effects of external electric field on enantioselectivity were also explored with reversal field direction. The changes correlate with catalyst decomposition.     

Tagging Live Cells that Express Specific Peptidase Activity with Solid‐State Fluorescence

A three‐component probe harnesses the extraordinary properties of a solid‐state fluorophore for the detection of living cells exhibiting a particular peptidase activity. The off–on mode by which the probe operates, the bright fluorescence of the resulting precipitate, and the rapid response allow an exceptional signal‐to‐background ratio during microscopic imaging. A tertiary carbamate link between the spacer and phenolic fluorophore is at the heart of the probe's long‐term stability. The degree of chlorination of the probe determines its response time and thus its suitability for live‐cell analysis. Our probe also allows highly resolved localization of peptidase activity during gel analysis or on agar. In comparison, probes releasing soluble fluorophores demonstrate complete diffusion of the fluorescent signal. These results demonstrate the probe's potential for diverse biomedical applications, including high‐fidelity flow cytometry and sensitive colony assays.     

The effect of TiO2, pigmentation on the hydrolysis of amino resin crosslinked epoxy can coatings

Pigmented (TiO₂), amino resin crosslinked coatings, designed for applications in can coatings’ internal lacquers, were formulated, characterized, applied, and cured. Three grades of a pigmentary form of TiO₂ were characterized in terms of their particle size, their particle morphology, their zeta potential, and their moisture retention behavior. Epoxy coatings that were crosslinked using one of several, different amino crosslinkers were prepared. The effect of the presence of the TiO₂ pigments on the hydrolysis of the cured coatings was monitored via the controlled retorting of the coatings. The different grades of TiO₂ pigment were selected, to establish whether or not they could be used interchangeably with respect to hydrolysis and to melamine release. Also, the effects of the aging of the fluid coatings on the amount of melamine released from the coatings (after curing and retorting) were monitored. Storage under laboratory conditions for 2, 20, and 40 weeks was used for this purpose. The TiO₂ pigment contributed significantly to the hydrolysis behavior of the epoxy coatings in that their presence substantially reduced the amount of melamine released and the extent of crosslinker hydrolysis. Typical results show that excluding the TiO₂ pigment particles from the formulation results in there being 50% more hydrolysis of the crosslinker to melamine. With respect to the melamine release and crosslinker hydrolysis, the different grades of the pigment gave similar results.     

Selection for intrabody solubility in mammalian cells using GFP fusions

Single-chain antibody fragments (scFv) expressed in the cytoplasm of mammalian cells, also called intrabodies, have many applications in functional proteomics. These applications are, however, limited by the aggregation-prone behaviour of many intrabodies. We show here that two scFv with highly homologous sequences and comparable soluble expression levels in Escherichia coli cytoplasm have different behaviours in mammalian cells. When over-expressed, one of the scFv aggregates in the cytoplasm whereas the second one is soluble and active. When expressed at low levels, using a retroviral vector, as a fusion with the green fluorescent protein (GFP) the former does not form aggregates and is degraded, resulting in weakly fluorescent cells, whereas the latter is expressed as a soluble protein, resulting in strongly fluorescent cells. These data suggest that the GFP signal can be used to evaluate the soluble expression of intrabodies in mammalian cells. When applied to a subset of an E.coli-optimised intrabody library, we showed that the population of GFP+ cells contains indeed soluble mammalian intrabodies. Altogether, our data demonstrate that the requirements for soluble intrabody expression are different in E.coli and mammalian cells, and that intrabody libraries can be directly optimised in human cells using a simple GFP-based assay.     

The Importance of Bridging Points for Charge Transport in Webs of Conjugated Polymer Nanofibers

Electrical characterizations on webs of highly ordered semiconducting polymer nanofibers (NFs) are often performed with large electrodes devices (millimeter scale) for which the carrier transport is an average between transport within isolated NFs and transport at the intersection of two or more NFs. In order to assess the nanoscale electrical properties of the NFs, a field‐effect transistor based on conductive atomic force microscopy is introduced that allows the visualization of the current distribution at the nanometer scale within a web of poly(3‐butylthiophene) NFs. The contact resistance is evaluated to be ≈4 kΩ cm, which does not limit the charge transport process, and the mobility in one single NF is μ_NF = 0.07 ± 0.03 cm² V^?1 s^?1. One NF can carry a current density of 20 kA cm^?2 without being destroyed. Moreover, by observing the current maps in detail, it is found that the electrical resistance associated with the bridging of two or more individual NFs does not reduce the charge transport inside the web of NFs. Finally, different kinds of bridging geometries are shown and the role of tie molecules is discussed.     

Thermostable Transketolase from Geobacillus stearothermophilus: Characterization and Catalytic Properties

Here we have characterized the first transketolase (TK) from a thermophilic microorganism, Geobacillus stearothermophilus, which was expressed from a synthetic gene in Escherichia coli. The G. stearothermophilus TK (mTK_gst) retained 100% activity for one week at 50 °C and for 3 days at 65 °C, and has an optimum temperature range around 60–70 °C, which will be useful for preparative applications and for future biocatalyst development. The thermostability of the mTK_gst allowed us to carry out an easy, one‐step purification by heat shock treatment of crude cell extracts at 65 °C for 45 min, directly yielding 132 mg of pure mTK_gst from 1 L of culture. The reaction rate of mTK_gst with glycolaldehyde was 14 times higher at 70 °C than at 20 °C, and 4 times higher at 50 °C when compared to E. coli TK under identical conditions. When tested at 50 °C with other aldehydes as acceptors, mTK_gst activity was approximately 3 times higher than those obtained at 20 °C. Applications of this new TK in biocatalysis were performed with hydroxypyruvate as donor and three different aldehydes as acceptors – glycolaldehyde, D ‐glyceraldehyde and butyraldehyde – from which the corresponding products L ‐erythrulose 1 , D ‐xylulose 2 and 1,3‐dihydroxyhexan‐2‐one 3 were obtained, respectively. The optical rotations for products 1 and 2 indicate that the stereospecificity of mTK_gst is identical to that of other TK sources, leading to a (3S) configuration. With the non‐hydroxylated substrate, butanal, the ee value was 85% (3S), showing higher enantioselectivity than the E. coli TK (75% ee, 3S). Processes at elevated temperatures could offer opportunities to extend the applications of TK biocatalysis, by favoring hydrophobic aldehyde acceptor substrate solubility and tolerance towards non‐conventional media.     

Applications and implications of nanotechnologies for the food sector

A review of current and projected nanotechnology-derived food ingredients, food additives and food contact materials is presented in relation to potential implications for consumer safety and regulatory controls. Nanotechnology applications are expected to bring a range of benefits to the food sector, including new tastes, textures and sensations, less use of fat, enhanced absorption of nutrients, improved packaging, traceability and security of food products. The review has shown that nanotechnology-derived food and health food products are set to grow worldwide and, moreover, a variety of food ingredients, additives, carriers for nutrients/supplements and food contact materials is already available in some countries. The current level of applications in the European food sector is at an elementary stage; however, it is widely expected that more and more products will be available in the EU over the coming years. The toxicological nature of hazard, likelihood of exposure and risk to consumers from nanotechnology-derived food/food packaging are largely unknown and this review highlights major gaps in knowledge that require further research. A number of uncertainties and gaps in relevant regulatory frameworks have also been identified and ways of addressing them proposed.