Stimulus-response bindings contribute to item switch costs in working memory.

In counter updating tasks, responses are typically faster when items repeat than when they change (item switch costs). The present study explored the contribution of stimulus-response bindings to these item switch costs. In two experiments, we orthogonally manipulated the repetition/switch of to-be-counted items and the repetition/switch of required manual responses.

Masked response priming in expert typists.

In masked priming tasks responses are usually faster when prime and target require identical rather than different responses. Previous research has extensively manipulated the nature and number of response-affording stimuli. However, little is known about the constraints of masked priming regarding the nature and number of response alternatives.

Bio-jETI: a framework for semantics-based service composition.

Background: The development of bioinformatics databases, algorithms, and tools throughout the last years has lead to a highly distributed world of bioinformatics services. Without adequate management and development support, in silico researchers are hardly able to exploit the potential of building complex, specialized analysis processes from these services. The Semantic Web aims at thoroughly equipping individual data and services with machine-processable meta-information, while workflow systems support the construction of service compositions.

Context-specific prime-congruency effects: on the role of conscious stimulus representations for cognitive control.

Recent research suggests that processing of irrelevant information can be modulated in a rapid online fashion by contextual information in the task environment depending on the usefulness of that information in different contexts. Congruency effects evoked by irrelevant stimulus attributes are smaller in contexts with high proportions of incongruent trials and larger in contexts with high proportions of congruent trials (e.g.

Highly regioselective gold-catalyzed ring-opening allylation and azidation of dihydrofurans.

The ring-opening allylation and azidation of 2,5-dihydrofurans has been accomplished with allyltrimethylsilane or Me(3)SiN(3) in the presence of catalytic amounts of HAuCl(4) x 3 H(2)O. Whereas the allylation proceeds regioselectively in the 2-position to afford 2,6-dien-1-ols, the azidation takes place in the 4-position exclusively.

Photolysis of difloxacin and sarafloxacin in aqueous systems.

The photodegradation of two fluoroquinolone veterinary antibiotics, difloxacin (DIF) and sarafloxacin (SARA) has been explored for the first time in aqueous systems. The study was performed to evaluate the influence of pH, inorganics, humic substances, and other additives. The drugs followed first-order degradation kinetics in matrix free aqueous medium with a rate constant 'k' value of 0.

Aggregation of amyloidogenic peptides near hydrophobic and hydrophilic surfaces.

The general effect of surface hydrophobicity/hydrophilicity on the aggregation of peptides is studied by simulations of oversaturated aqueous solutions of hydrophobic and hydrophilic amyloidogenic peptides. Peptide aggregation was studied in bulk solution, in solutions confined between hydrophobic boundaries (smooth planar paraffin-like surfaces and liquid-vapor interfaces) and in solutions confined between hydrophilic surfaces (smooth planar silica-like surfaces). Aggregation of hydrophobic peptides strongly enhances due to the confinement between hydrophobic surfaces with all peptides adsorbed at the boundaries and aligned predominantly parallel to them.

Thermal expansivity of amyloid beta(16-22) peptides and their aggregates in water.

Temperature dependence of the volumetric and structural properties of Abeta(16-22) peptides (wild type and pathogenic forms) and their aggregates in water was studied by simulations. The intrinsic thermal expansion coefficient alpha(p) of peptides was evaluated by taking into account the difference between the volumetric properties of hydration and bulk water. Single peptides show mainly positive values of alpha(p) that correlates with the increasing number of intrapeptide hydrogen bonds upon heating.

Visual and tactile action effects determine bimanual coordination performance.

Effect-based models of motor control assign a crucial role to anticipated perceptual feedback in action planning. Two experiments were conducted to test the validity of this proposal for discrete bimanual key press responses. The results revealed that the normally observed performance advantage for the preparation of two responses with homologous rather than non-homologous fingers becomes inverted when homologous fingers produce non-identical visual effects, and non-homologous fingers produce identical visual effects.

Marasmius scorodonius extracellular dimeric peroxidase - exploring its temperature and pressure stability.

The temperature and pressure dependent stability and function of MsP1, an uncommon peroxidase from the basidiomycetous fungus Marasmius scorodonius were investigated. To this end, a series of biophysical techniques (DSC, fluorescence and FTIR spectroscopy, small-angle X-ray scattering) were combined with enzymatic studies of the enzyme. The dimeric MsP1 turned out to be not only rather thermostable, but also highly resistant to pressure, i.

Fluorescence microscopy studies on islet amyloid polypeptide fibrillation at heterogeneous and cellular membrane interfaces and its inhibition by resveratrol.

Type II diabetes mellitus (T2DM) is a disease characterized by progressive deposition of amyloid in the extracellular matrix of beta-cells. We investigated the interaction of the islet amyloid polypeptide (IAPP) with lipid model raft mixtures and INS-1E cells using fluorescence microscopy techniques. Following preferential partitioning of IAPP into the fluid lipid phase, the membrane suffers irreversible damage and predominantly circularly-shaped lipid-containing IAPP amyloid is formed.

Gold-catalyzed cycloisomerization of alk-4-yn-1-ones.

Depending on the substitution pattern and the solvent, the gold-catalyzed cyclization of alk-4-yn-1-ones affords different oxygen heterocycles under mild reaction conditions. Alkynones with one substituent at C-3 undergo a 5-exo-dig cycloisomerization to substituted furans , whereas a 6-endo-dig cyclization to 4H-pyrans is observed with substrates bearing two substituents at C-3. In alcoholic solvents, alkylidene/benzylidene-substituted tetrahydrofuranyl ethers are formed in a tandem nucleophilic addition/cycloisomerization.

Nonmonotonic crossover from adsorption to desorption in supercritical fluid near a weakly attractive surface.

The density profiles of a supercritical Lennard-Jones fluid near a weakly attractive surface are used to study the excess adsorption Gamma of supercritical fluid in a wide density range. We report the observation of two extrema of Gamma along the isotherm as a function of density. The attractive fluid-wall interaction potential tends to make Gamma positive, whereas the missing neighbor effect tends to make Gamma negative.

Degradation of a chiral nonylphenol isomer in two agricultural soils.

The degradation of a chiral nonylphenol isomer, 4-(1-ethyl-1,4-dimethylpentyl)phenol (NP(112)), in two agricultural soils from Monheim and Dortmund, Germany has been studied. The degradation of NP(112) and the formation of a nitro-nonylphenol metabolite were determined by means of GC-MS analysis. The degradation followed bi-exponential order kinetics, with half-life of less than 5 days in both soils.

Rhodium(I)-catalyzed enantioselective C-C bond activation.

Relieving the strain: The rhodium(I)-catalyzed activation of C-C bonds in functionalized cyclobutanes opens a novel route to highly substituted carbo- and heterocycles. Particularly intriguing is the differentiation of enantiotopic C-C bonds, which leads to the formation of highly enantiomerically enriched lactones, cyclopentanones, and cyclohexenones (see scheme).

Influence of the lipidation motif on the partitioning and association of N-Ras in model membrane subdomains.

In a combined chemical biological and biophysical approach using time-lapse tapping-mode atomic force microscopy, we studied the partitioning of differently lipidated N-Ras proteins with various membrane-localization motifs into lipid domains of canonical model raft mixtures. The results provide direct evidence that partitioning of N-Ras occurs preferentially into liquid-disordered lipid domains, independent of the lipid anchor system. N-Ras proteins bearing at least one farnesyl group have a comparable membrane partitioning behavior and show diffusion of the protein into the liquid-disordered/liquid-ordered phase boundary region, thus leading to a decrease of the unfavorable line tension between domains.

First total synthesis of (R,R,R)- and (3R,5S,9R)-bejarol by gold-catalyzed allene cycloisomerization and determination of absolute configuration of the natural product.

The first total synthesis of (R,R,R)-bejarol and its (3R,5S,9R)-isomer has been accomplished which confirms the absolute configuration of the natural products. The key step is the gold-catalyzed cycloisomerization of the enantiomerically pure beta-hydroxyallenes 12/13 to the corresponding dihydropyrans 14/15.

Which properties of a spanning network of hydration water enable biological functions?

The central role of water in biological functions is well-recognized, but numerous questions concerning the physical mechanisms behind the importance of water for life remain unanswered. Water in biosystems exists mainly as hydration water. Analysis of the phase diagram of hydration water shows that biological functions are possible only when the surfaces of biomolecules are covered by spanning hydrogen-bonded networks of hydration water.

Multiple phases of liquid water.

The history of the study of the anomalies of liquid water, from the 17th century up to the present, is reviewed and the current view on the origin of these anomalies is summarized. The hypothesis of the multiple liquid-liquid transitions of water in the supercooled region is consistent with the available experimental and simulation data and provides physical explanation of water behavior in a wide thermodynamic range. The general character of the liquid-liquid transitions of fluids is discussed and the remaining questions are formulated.

Intrinsic thermal expansivity and hydrational properties of amyloid peptide Abeta42 in liquid water.

Volumetric and conformational properties of the amyloid beta(1-42) peptide (Abeta(42)) are studied in relation to the properties of hydration water in a wide temperature range by computer simulations. The apparent volume of Abeta(42), which is the change in the total volume of the solution due to the presence of Abeta(42), shows a quite different temperature dependence below and above T approximately 320 K. The apparent thermal expansion coefficient alpha(app)(Abeta(42)) is about 1.

Comparison of two spatial optimization techniques: a framework to solve multiobjective land use distribution problems.

Two spatial optimization approaches, developed from the opposing perspectives of ecological economics and landscape planning and aimed at the definition of new distributions of farming systems and of land use elements, are compared and integrated into a general framework. The first approach, applied to a small river catchment in southwestern France, uses SWAT (Soil and Water Assessment Tool) and a weighted goal programming model in combination with a geographical information system (GIS) for the determination of optimal farming system patterns, based on selected objective functions to minimize deviations from the goals of reducing nitrogen and maintaining income. The second approach, demonstrated in a suburban landscape near Leipzig, Germany, defines a GIS-based predictive habitat model for the search of unfragmented regions suitable for hare populations (Lepus europaeus), followed by compromise optimization with the aim of planning a new habitat structure distribution for the hare.

Effects of temperature and pressure on the lateral organization of model membranes with functionally reconstituted multidrug transporter LmrA.

To contribute to the understanding of membrane protein function upon application of pressure, we investigated the influence of hydrostatic pressure on the conformational order and phase behavior of the multidrug transporter LmrA in biomembrane systems. To this end, the membrane protein was reconstituted into various lipid bilayer systems of different chain length, conformation, phase state and heterogeneity, including raft model mixtures as well as some natural lipid extracts. In the first step, we determined the temperature stability of the protein itself and verified its reconstitution into the lipid bilayer systems using CD spectroscopic and AFM measurements, respectively.

Modeling of aqueous poly(oxyethylene) solutions. 2. Mesoscale simulations.

We extend our work on aqueous solutions of poly(oxyethylene) oligomers H-(CH2-O-CH2)n -H (POEn). On the basis of atomistic simulations of trimer and decamer solutions (first part of this series of papers), different sets of coarse-grained implicit-solvent potentials have been constructed using the iterative Boltzmann inversion technique. The comparison of structures obtained from coarse-grained simulations (gyration radii, end-to-end distances, radial distribution functions) with atomistic reference simulations and experiments shows that the state-specific potentials are transferable both to a wide concentration range, if the same molecule size is considered, and to at least 2 orders of magnitude larger molecules (in terms of molecular mass).