Dental Inlay and Onlay Construction by Iterative Laplacian Surface Editing

We propose a new method for automatic construction of inlays and onlays. Mesh models from a small tooth library are adapted to the remaining healthy surface of the patient's tooth. In the area above the cavity, the general morphology of the model tooth (fissures, cusp tips, etc) is preserved, but precisely adjusted to the intra‐oral situation. Our approach uses iterative Laplacian Surface Editing to deform the model tooth. This allows the automatic generation of highly individual, functional and anatomically correct inlays/onlays, without having to resort to a large library of different tooth shapes.     

Influence of groove characteristics on strength of form-fit joints

Joining by electromagnetic forming (EMF) is an innovative method to connect, e.g. extruded aluminum profiles to lightweight frame structures without heating or penetrating the profile. This article describes the joining of extruded aluminum profiles by electromagnetic forming, taking into account the process characteristics and the joint design. Forming is initiated by a magnetic impulse of high energy density, such that material with high electrical conductivity is deformed by Lorentz forces. With this high-speed forming process high-strength joints can be manufactured as interference fits, form fits, impact welded joints or a combination of these types. The focus of this paper is on form-fit joints of extruded aluminum profiles for lightweight frame structures. Based on fundamental technological investigations the parameters which specifically affect the strength of the joints were identified and analyzed. Throughout these experiments the groove geometry was varied size and shape wise. The influence of the acting magnetic pressure and the charging energy on the joint strength was also analyzed for the various groove geometries.     

CD9-mediated costimulation of TCR-triggered naive T cells leads to activation followed by apoptosis

The induction of full activation or death in TCR-triggered T cells depends largely on whether appropriate costimulatory signals are provided. In this study, we show that the costimulation of CD9 on naive T cells during TCR stimulation results in transient, albeit potent, activation followed by apoptosis, rather than full activation. Anti-CD9 mAb synergized with suboptimal doses of anti-CD3 mAb in inducing T cell activation. [3H]TdR incorporation determined 2 days after CD9 costimulation was as potent as that induced by CD28 costimulation. In contrast to progressive T cell proliferation induced by CD28 costimulation, CD9 costimulation led to the induction of apoptosis of once-activated T cells. Although IL-2R expression was induced significantly earlier and to a greater degree after CD9 costimulation than after CD28 costimulation, CD9 costimulation only transiently produced a small amount of IL-2 and induced apparently low levels of bcl-xL compared with those observed in CD28 costimulation. Addition of rIL-2 to cultures of CD9 costimulation induced strikingly enhanced expression of bcl proteins, especially of bcl-xL, and protected TCR-stimulated T cells from apoptosis. These data indicate that CD9-mediated costimulation of TCR-triggered naive T cells leads to activation followed by apoptosis as the result of failure to generate a positive signal for sufficient levels of IL-2 production.     

Hydrogen quantification of magnetron sputtered hydrogenated amorphous carbon (a-C:H) coatings produced at various bias voltages and their tribological behavior under different humidity levels

Hydrogenated amorphous carbon (a-C:H) films have extraordinary tribological properties under dry conditions since the C-atoms at the surface are hydratized and not available for any bonding with the opposing material. Under wet conditions water molecules are weakly absorbed by the a-C:H-coatings so the interaction between the coating surface and the tribological counterpart changes to a dipole-like interaction which is disadvantageous for the tribological performance. According to this, the hydrogen-content plays an important role in the wear and friction behavior of diamond-like carbon (DLC) coatings under different humid conditions.This work focuses on the quantification of the hydrogen content of differently bias a-C:H top layered coating systems and their influence on the tribological behavior under different humidity conditions. By means of a magnetron sputter device DLC-coating systems with an a-C:H-top layer have been deposited at bias voltages between ? 75 and ? 200 V. In order to quantify the hydrogen content of the layers Nuclear Reaction Resonance Analysis (NRRA) was used. In combination with the results of the tribological tests under different humid conditions using a ball-on-disk-tester, correlations between the hydrogen content, the bias voltage and the wear and friction performance were made. A clear relationship between the bias voltage and the hydrogen content has been observed, since the values decrease consistently from 27.2 at.% at ? 75 V to a minimum of 19.9 at.% at ? 200 V bias voltage. Furthermore the different humidity levels show a strong influence on the tribological performance, while the bias voltage effects mainly the wear and friction results of the samples tested under wet conditions.     

The Manufacture and Characterisation of Reinforced Magnesium Foams

In the project introduced here, the manufacture of light‐metal foams based on magnesium are investigated and enhanced. Such foams possess an excellent mass‐volume ratio and are therefore perfectly suited as light and effective reinforcing elements. Apart from other functional properties, their suitability as energy absorbing crash elements is to be particularly emphasised and is the focus of the investigations here. In the case of impact loading, the energy is largely transformed into the work of plastic deformation during a reduction in volume. Although metallic foams themselves possess only low absolute strengths, it is expedient to employ them in the form of material combinations like sandwich structures or composites by integrating additional internal reinforcing elements. The latter approach is pursued in the present project. Both the initial results of the feasibility study and also the metallographic and mechanical investigations for characterising reinforced magnesium foams are presented.     

Adapting of the Background-Oriented Schlieren (BOS) Technique in the Characterization of the Flow Regimes in Thermal Spraying Processes

In thermal spraying technique, the changes in the in-flight particle velocities are considered to be only a function of the drag forces caused by the dominating flow regimes in the spray jet. Therefore, the correct understanding of the aerodynamic phenomena occurred at nozzle out let and at the substrate interface is an important task in the targeted improvement in the nozzle and air-cap design as well as in the spraying process in total. The presented work deals with the adapting of an innovative technique for the flow characterization called background-oriented Schlieren. The flow regimes in twin wire arc spraying (TWAS) and high velocity oxygen fuel (HVOF) were analyzed with this technique. The interfering of the atomization gas flow with the intersected wires causes in case of TWAS process a deformation of the jet shape. It leads also to areas with different aero dynamic forces. The configurations of the outlet air-caps in TWAS effect predominantly the outlet flow characteristics. The ratio between fuel and oxygen determine the dominating flow regimes in the HVOF spraying jet. Enhanced understanding of the aerodynamics at outlet and at the substrate interface could lead to a targeted improvement in thermal spraying processes.     

Damascene TiN-Gd2O3-gate stacks: Gentle fabrication and electrical properties

In this work, we present MOS capacitors and field effect transistors with a crystalline gadolinium oxide (Gd₂O₃) gate dielectric and metal gate electrode (titanium nitride) fabricated in a gentle damascene gate last process. Details of the gate last process and initial results on MOS devices with equivalent oxide thicknesses (EOT) of 3.0 nm and 1.5 nm, respectively, are shown.     

Priming in melody perception: Tracking down the strength of cognitive expectations.

The musical priming paradigm has shown facilitated processing for tonally related over less-related targets. However, the congruence between tonal relatedness and the psychoacoustical properties of music challenges cognitive interpretations of the involved processes. Our goal was to show that cognitive expectations (based on listeners' tonal knowledge) elicit tonal priming in melodies independently of sensory components (e.g., spectral overlap). A first priming experiment minimized sensory components by manipulating tonal relatedness with a single note change in the melodies. Processing was facilitated for related over less-related target tones, but an auditory short-term memory model succeeded in simulating this effect, thus suggesting a sensory-based explanation. When the same melodies were played with pure tones (instead of piano tones), the sensory model failed to differentiate between related and less-related targets, while listeners' data continued to show a tonal relatedness effect (Experiment 2). The tonal priming effect observed here thus provides strong evidence for the influence of listeners' tonal knowledge on music processing. The overall findings point out the need for controlled musical material (and notably beyond tone repetition) to study cognitive components in music perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)