Rugulactone and its analogues exert antibacterial effects through multiple mechanisms including inhibition of thiamine biosynthesis

Rugulactone is a dihydro-α-pyrone isolated from the plant Cryptocarya rugulosa in 2009. It has been reported to display IkB kinase (IKK) inhibitory activity, as well as antibiotic activity in several strains of pathogenic bacteria. However, its biological targets and mode of action in bacteria have not yet been explored. Here we present enantioselective syntheses of rugulactone and of some corresponding activity-based protein profiling (ABPP) probes. We found that the ABPP probes in this study are more potent than rugulactone against Staphyloccocus aureus NCTC 8325, S. aureus Mu50, Listeria welshimeri SLCC 5334 and Listeria monocytogenes EGD-e, and that molecules of this class probably exert their antibacterial effect through a combination of targets. These targets include covalent inhibition of 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate (HMPP) kinase (ThiD), which is an essential component of the thiamine biosynthesis pathway in bacteria. This represents the first example of a small-molecule inhibitor of ThiD.     

The Effects fo Speed,Load, and Film Thickness on the Performance of Gas-Lubricated,Tilting-Pad Journal Bearings

This paper deals with the effects of lubricant compressibility on the pressure profile and total load capacity in a partial journal bearing; pivot pressure as a measure of shoe load capacity; shoe friction characteristics; and optimum shoe clearnace ratios for various speeds. The parameter A is used as an indicator of the compressibility effect of gas in the bearing clearance.     

Surface Integrity and Wear Behavior of Ground Ceramics

The present study intends to cast some light upon the performance of ceramic parts ground with diamond and to determine the extent of improvement possible by an adapted finishing process. From the analysis of material removal in grinding, a model was derived which predicts the state of stress in the machined surface and thus the likely behavior of parts in service.     

In-Operation Monitoring of the Soot Load of Diesel Particulate Filters: Initial Tests

Diesel particulate filters (DPF) are indispensable parts of modern automotive exhaust gas aftertreatment systems due to the stringent emissions legislation. For a fuel-efficient control strategy, it would be beneficial to determine directly and in-operation their actual trapped soot mass. Two novel approaches—based on the electrical conductivity of trapped soot particles—emerged recently. By measuring the electrical resistance between different single walls inside the filter, the soot load is determined with local resolution. The microwave-based technique is a contactless approach that gives an integral value depending on the soot mass in the DPF. We present investigations on loading and regeneration of DPFs in a dynamometer test bench applying both methods. The results are compared with each other and correlated with the differential pressure and the soot mass. Especially the microwave-based technique has a potential for serial application.     

Numerical Modeling of Turbulent Melt Flow in a Continuous Casting Mold Affected by an Electromagnetic Brake

The current work combines numerical and experimental investigations based on a small-scale mockup using the eutectic alloy GaInSn.The jet flow discharging from the submerged entry nozzle was exposed perpendicularly to a DC magnetic field across the entire wide face of the mold.Numerical calculations were performed by using the commercial package CFX with an implemented RANS-SST turbulence model.The anisotropic properties of the MHD turbulence were taken into account by specific modifications of the turbulence model.The comparison between our numerical calculations and the experimental results shows a very well agreement.In particular,the modified RANS-SST turbulence model is capable to reconstruct the peculiar phenomenon of the excitation of non-steady,non-isotropic large-scale flow perturbations caused by the application of the DC magnetic field.Another important finding of our study is the feature that the electrical boundary conditions,namely the wall conductivity ratio,have a great impact on the mold flow subjected to an external magnetic field.     

Diffusion of a hydrocarbon mixture in a one-dimensional zeolite channel: An exclusion model approach

Zeolite channels can be used as effective hydrocarbon traps. Earlier experiments [K.F. Czaplewski et al., Micropor. Mesopor. Mater. 56 (2002) 55] show that the presence of large aromatic molecules (toluene) block the diffusion of light hydrocarbon molecules (propane) inside the narrow pore of a zeolite sample. As a result, the desorption temperature of propane is significantly higher in the binary mixture than in the single-component case. In order to obtain further insight into these results, we use a simple lattice gas model of diffusion of hard-core particles to describe the diffusive transport of two species of molecules in a one-dimensional zeolite channel. Our dynamical Monte Carlo simulations show that taking into account an Arrhenius dependence of the single-molecule diffusion coefficient on temperature, one can explain many significant features of the temperature programmed desorption profile observed in experiments. However, on a closer comparison of the experimental curve and our simulation data, we find that it is not possible to reproduce the higher propane current than toluene current near the desorption peak seen in experiment. We argue that this is caused by a violation of strict single-file behavior.     

Factors affecting motion integration

The perceived direction of motion of a featureless contour inside a circular aperture is always perpendicular to the contour's orientation, regardless of its true motion (the aperture problem). This study investigates the circumstances under which unambiguous feature motion (of line terminators, single dots, or truncations of a D6 pattern) in adjacent apertures can alter the perceived direction of such featureless contours. We find that integration mechanisms responsible for motion capture are fairly robust against misorientations and contrast manipulations of individual components, are sensitive to differences in spatial frequencies, and scale with pattern size. Motion capture is not diminished when a D6 profile is substituted for the square-pulse profile of a line and is independent of the visibility of the apertures, indicating that object interpretations and three-dimensional analyses of a scene are less important than has been postulated previously. These results have strong implications for the neuronal hardware underlying the integration of motion signals across space and provide a framework for global motion models.