Dissociating local and global levels of perceptuo-motor control in masked priming.

[Correction Notice: An erratum for this article was reported in Vol 33(3) of Journal of Experimental Psychology: Human Perception and Performance (see record 2007-07213-006). Figure 5 was inadvertently duplicated in the production process and was incorrectly substituted in place of the original Figure 6 submitted by the authors. The correct figure and caption that should have appeared for Figure 6 are listed in the erratum.] Masked prime stimuli presented near the threshold of conscious awareness affect responses to subsequent targets. The direction of these priming effects depends on the interval between masked prime and target. With short intervals, benefits for compatible trials (primes and targets mapped to the same response) and costs for incompatible trials are observed. This pattern reverses with longer intervals. We argue (a) that these effects reflect the initial activation and subsequent self-inhibition of the primed response, and the corresponding inhibition and subsequent disinhibition of the nonprimed response, and (b) that they are generated at dissociable local (within response channels) and global (between channels) levels of motor control. In two experiments, global-level priming effects were modulated by changing the number of response alternatives, whereas local-level effects remained unaffected. These experiments suggest that low-level motor control mechanisms can be successfully decomposed into separable subcomponents, operating at different levels within the motor system. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

X-ray reflectivity study of cyclic peptide monolayers at the air-water interface

The dynamic and living characteristics of monolayers at the air-water interface of a cyclohexapeptide ( C6G ) and a cyclooctapeptide ( C8G ), both composed of glutamic acid and 3-aminobenzoic acid subunits in an alternating sequence, were investigated using the Langmuir balance technique, Brewster angle microscopy (BAM), and X-ray reflectivity (XR). An alanine-containing cyclohexapeptide ( C6A ) was included in this study for comparison. All three cyclopeptides preferentially adopt an orientation parallel to the subphase at low surface pressure. Continuous compression then causes the molecules to flip to a perpendicular state, thus minimizing their molecular area. In contrast to C8G and C6A , a pronounced hysteresis observed during the compression-expansion cycle of C6G indicates that strong intermolecular interactions between the cyclopeptide rings occur in the monolayers of this peptide. This result is supported by BAM measurements that show the formation of crystallite structures for C6G at high surface pressures, whereas no structures were observed for C8G and C6A . These results indicate that C6G is able to self-assemble upon surface compression, an ability that is obviously critically dependent on the correct ring size and composition of the peptide. The presence of hydrogen bond acceptors in the side chains of C6G suggests that the structural stabilization of the monolayer is due to H-bonding, possibly between ring NH groups and side chain CO groups. Our in situ study thus provides a detailed understanding of the molecular dynamics and uninterrupted interfacial behavior of the three peptides in a real-time frame.     

Using Knock-Out Mutants to Investigate the Adhesion of Staphylococcus aureus to Abiotic Surfaces

The adhesion of Staphylococcus aureus to abiotic surfaces is crucial for establishing device-related infections. With a high number of single-cell force spectroscopy measurements with genetically modified S. aureus cells, this study provides insights into the adhesion process of the pathogen to abiotic surfaces of different wettability. Our results show that S. aureus utilizes different cell wall molecules and interaction mechanisms when binding to hydrophobic and hydrophilic surfaces. We found that covalently bound cell wall proteins strongly interact with hydrophobic substrates, while their contribution to the overall adhesion force is smaller on hydrophilic substrates. Teichoic acids promote adhesion to hydrophobic surfaces as well as to hydrophilic surfaces. This, however, is to a lesser extent. An interplay of electrostatic effects of charges and protein composition on bacterial surfaces is predominant on hydrophilic surfaces, while it is overshadowed on hydrophobic surfaces by the influence of the high number of binding proteins. Our results can help to design new models of bacterial adhesion and may be used to interpret the adhesion of other microorganisms with similar surface properties.     

The risk of transfer of foodborne bacterial hazards in Turkey through the consumption of meat; risk ranking of muscle foods with the potential to transfer Campylobacter spp.

This paper presents a simple approach to semi-quantitatively estimating the risk for human foodborne campylobacteriosis in Turkey, with a focus on typical/traditional meat and meat dishes. The following factors are considered: prevalence/concentration of the pathogen in raw meat according to species, changes in the pathogen’s titre as a result of heat treatment and cross-contamination, serving frequency and size, and demographic data. Regional differences as well as differences between social groups are considered in particular. The biological hazard “Campylobacter” is characterized as associated with conditions prevailing in the meat chain and this information is linked to food consumption and other data thus allowing an estimate of consumers’ exposure to Campylobacter via typical Turkish meat dishes. The latter are ranked on the basis of the presence of meat components and the associated risks.     

First Ring-Expanded Maytansin Lactone Accessed by a New Mutasynthetic Variant

A multiblocked mutant strain (ΔAHBA and Δasm12, asm21) of Actinosynnema pretiosum, the producer of the highly toxic maytansinoid ansamitocin, has been used for the mutasynthetic production of new proansamitocin derivatives. The use of mutant strains that are blocked in the biosynthesis of an early building block as well as in the expression of two tailoring enzymes broadens the scope of chemo-biosynthetic access to new maytansinoids. Remarkably, a ring-expanded macrolactone derived from ansamitocin was created for the first time.     

Quantitative matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis of synthetic polymers and peptides

Matrix-assisted laser desorption ionization (MALDI) is a very powerful and widely used mass spectrometric technique to ionize high molecular weight compounds. The most commonly used dried droplet (DD) technique can lead to a concentration distribution of the analyte on the target and is therefore often not suitable for reproducible analyses. We developed a new solvent-free deposition technique, called compressed sample (CS), to prevent the distribution of the analytes caused by the crystallization of the compounds. The CS technique presented in this work allows the quantitative analysis of synthetic polymers such as derivatized maltosides with correlation coefficients of 0.999 and peptides up to 3500 Da with correlation coefficients of at least 0.982 without the use of stable-isotope-labeled standards.     

Beidseitige Innen‐ und Außenbeschichtung von PET‐Getränkeflaschen

Double‐sided interior and exterior coating of PET beverage bottles Plasma‐enhanced methods for the interior coating of PET beverage bottles have already been put into practice in the industry. Thereby the achieved barrier properties are limited due to defects in the coating, which emerge during the layer growth and allow a higher permeability. One possible way to improve barrier properties is the double‐sided coating. The implementation of the concept in form of a demonstrator plant is presented. By means of optical emission spectroscopy (OES) as a very versatile and easy to use method for the surveillance of industrial plasma processes, the influence of the gas composition on the plasma homogeneity and barrier properties of the coating is demonstrated. Permeation measurements are carried out, showing the potential of the combined coating process for the deposition of effective coatings.     

Action prediction with the Jordan model of human intention: a contribution to cooperative control

Cognition, Technology & Work - Human intentions are internal processes that can be deduced by observation of their resulting actions. Hence, an observation-based model of human intention is...     

N-nitrosamines migrating from food contact materials into food simulants: analysis and quantification by means of HPLC-APCI-MS/MS

It was the aim of the work described here to develop a validated analytical method for the determination of N-nitrosamines in food simulants. Here, we present the validation of a liquid chromatography–atmospheric pressure chemical ionisation–tandem mass spectrometry method for the determination of 13 N-nitrosamines in the food simulants deionised water, 3% acetic acid and 10% ethanol. Method validation encompassed linearity, LOD, LOQ, recovery, precision and stability of the N-nitrosamines. The method was found to be sufficiently rugged and suitable for routine analysis. In addition, the developed method is on average 10 times more sensitive than the gas chromatography–thermal energy analyser (GC-TEA) method that is currently stipulated in Recommendation XXI for commodities based on natural and synthetic rubber issued by the German Federal Institute for Risk Assessment (BfR). The developed method was applied to determine the N-nitrosamine contents in migration solutions of 12 elastomer samples covering a range of different elastomer types. In 10 out of 12 samples, N-nitrosamines were determined. In most samples, the guidance value of 1 µg/dm² specified in BfR Recommendation XXI was not exceeded. In conclusion, the analytical method presented here offers a useful alternative to the GC-TEA method currently stipulated in BfR Recommendation XXI. This is of wider relevance, since BfR recommendations are used for compliance assessment of Article 3, paragraph 1 a of the Regulation (EC) No. 1935/2004 with respect to their health safety.