Inhibitors of \u3cem\u3eN\u3csup\u3eα\u3c/sup\u3e\u3c/em\u3e-acetyl-l-ornithine Deacetylase: Synthesis, Characterization and Analysis of their Inhibitory Potency

A series of N α-acyl (alkyl)- and N α-alkoxycarbonyl-derivatives of l- and d-ornithine were prepared, characterized, and analyzed for their potency toward the bacterial enzyme N α-acetyl-l-ornithine deacetylase (ArgE). ArgE catalyzes the conversion of N α-acetyl-l-ornithine to l-ornithine in the fifth step of the biosynthetic pathway for arginine, a necessary step for bacterial growth. Most of the compounds tested provided IC50 values in the μM range toward ArgE, indicating that they are moderately strong inhibitors. N α-chloroacetyl-l-ornithine (1g) was the best inhibitor tested toward ArgE providing an IC50 value of 85 μM while N α-trifluoroacetyl-l-ornithine (1f), N α-ethoxycarbonyl-l-ornithine (2b), and N α-acetyl-d-ornithine (1a) weakly inhibited ArgE activity providing IC50 values between 200 and 410 μM. Weak inhibitory potency toward Bacillus subtilis-168 for N α-acetyl-d-ornithine (1a) and N α-fluoro- (1f), N α-chloro- (1g), N α-dichloro- (1h), and N α-trichloroacetyl-ornithine (1i) was also observed. These data correlate well with the IC50 values determined for ArgE, suggesting that these compounds might be capable of getting across the cell membrane and that ArgE is likely the bacterial enzymatic target

Micro-manufacturing : research, technology outcomes and development issues

Besides continuing effort in developing MEMS-based manufacturing techniques, latest effort in Micro-manufacturing is also in Non-MEMS-based manufacturing. Research and technological development (RTD) in this field is encouraged by the increased demand on micro-components as well as promised development in the scaling down of the traditional macro-manufacturing processes for micro-length-scale manufacturing. This paper highlights some EU funded research activities in micro/nano-manufacturing, and gives examples of the latest development in micro-manufacturing methods/techniques, process chains, hybrid-processes, manufacturing equipment and supporting technologies/device, etc., which is followed by a summary of the achievements of the EU MASMICRO project. Finally, concluding remarks are given, which raise several issues concerning further development in micro-manufacturing

Perspective taking and systematic biases in object location memory.

The aim of the current study was to develop a novel task that allows for the quick assessment of spatial memory precision with minimal technical and training requirements. In this task, participants memorized the position of an object in a virtual room and then judged from a different perspective, whether the object has moved to the left or to the right. Results revealed that participants exhibited a systematic bias in their responses that we termed the reversed congruency effect. Specifically, they performed worse when the camera and the object moved in the same direction than when they moved in opposite directions. Notably, participants responded correctly in almost 100% of the incongruent trials, regardless of the distance by which the object was displaced. In Experiment 2, we showed that this effect cannot be explained by the movement of the object on the screen, but that it relates to the perspective shift and the movement of the object in the virtual world. We also showed that the presence of additional objects in the environment reduces the reversed congruency effect such that it no longer predicts performance. In Experiment 3, we showed that the reversed congruency effect is greater in older adults, suggesting that the quality of spatial memory and perspective-taking abilities are critical. Overall, our results suggest that this effect is driven by difficulties in the precise encoding of object locations in the environment and in understanding how perspective shifts affect the projected positions of the objects in the two-dimensional image

Novel process for butt-joined plastic-metal hybrid compounds

Particularly in the automotive industry, there is a persistent problem arising from the need to reliably and permanently bond dissimilar materials such as plastics and metals. To solve this problem, experts at the Fraunhofer ILT in Aachen have come up with a solution that is suitable for industrial applications. Unlike adhesive bonding, the process works without additives or additional intervals for hardening or surface cleaning. Starting from the state-of-the-art process used today, the chain can be optimized for butt connections to a novel process using the thermal energy applied by the microstructuring process of the metal component. A new joining device is introduced, which allows the microstructuring of the metal component with an angle of incidence. After heating the component by the microstructuring process, it is pressed into the plastic component in the same joining device. The liquid plastic flows inside the inclined microstructures, which have a big undercut groove and a barb-like effect in the tensile shear load direction. After curing, the connection is based on a mechanical interlocking between the two components. At first suitable microstructuring parameters are evaluated to achieve a homogeneous melt flow of the plastic inside the cavities, which enables a high structure filling-rate and a good mechanical performance of the joint in tensile shear tests. Furthermore, the resulting temperature distribution is evaluated by thermocouples. Different influencing factors on the strength are evaluated like various penetration depths, different structure distances, or different clamping offsets of the plastic component

Hybrid simulation of laser deep penetration welding

Beim Tiefschweißen mit Laserstrahlung ist die Kenntnis der Temperaturgeschichte des Materials von großem Interesse für die Beurteilung der Qualitätseigenschaften des Schweißergebnisses. Zu diesem Zweck wird ein hybrides Prozessmodell herangezogen, das die schnelle Berechnung von Temperaturverteilungen in Abhängigkeit der Laserstrahlparameter ermöglicht. Die Wechselwirkung zwischen Laserstrahl und Material wird durch ein reduziertes Modell berücksichtigt, das eine bei hohen Vorschubgeschwindigkeiten auftretende Hierarchie in den räumlichen Dimensionen ausnutzt. Die daraus resultierende Form einer stationären Kapillare wird als Dirichlet‐Rand in eine thermische Finite‐Elemente‐Simulation eingebettet, in der sie gemäß der Prozessführung des Laserstrahls durch das Werkstück bewegt wird. Der Rand wird mathematisch durch eine Level‐Set‐Funktion beschrieben und in ein festes Rechengitter eingetaucht. Die Dirichlet‐Randbedingung wird unter Verwendung einer Embedded‐Boundary‐Methode gesetzt. Die berechneten Temperaturverteilungen werden anhand von Blindschweißungen in 0,9 mm dicken Blechen aus 1.4301 (AISI 304) Edelstahl bewertet