Application of UV depth lithography and 3D-microforming for high aspect ratio electromagnetic microactuator components

 This paper was presented at the Fourth International Workshop on High Aspect Ratio Micro-Structure Technology (HARMST) 2001 in Baden-Baden, Germany. For building high aspect ratio parts, using a combination of UV lithography and electroplating is a very promising approach. This paper describes investigations regarding the application of UV lithography and electroplating to fabricate high aspect ratio component parts of microactuators, such as coils and pole pieces. As resist materials, both novolac-based resists and photosensitive epoxy were investigated. The high aspect ratio photomasks were used as micromolds for electroplating coils and magnetic structures in micromotors. Received: 10 August 2001/Accepted: 24 September 2001     

Tribology of microsystems

In this work the possibilities for the reduction of friction and wear in micro electro-mechanical systems (MEMS) are investigated. An improvement of the tribological behaviour of microsystems can be realized by optimizing the contact condition and by application of special coatings with low friction and low wear rates. For optimizing the contact condition a defined topography and surface profile is generated by photolithography. Furthermore tribological coatings with low friction and low wear rates are developed and investigated using nanoindentation and micro scratch experiments. Also novel results on micro structured surfaces coated with a-C:H and a-C films will be discussed. The results show the great potential of carbon-based coatings in combination with an optimized geometrical surface design.     

Response bias in "remembering" emotional stimuli: A new perspective on age differences.

Older adults sometimes show a recall advantage for emotionally positive, rather than neutral or negative, stimuli (S. T. Charles, M. Mather, & L. L. Carstensen, 2003). In contrast, younger adults respond "old" and "remember" more often to negative materials in recognition tests. For younger adults, both effects are due to response bias changes rather than to enhanced memory accuracy (S. Dougal & C. M. Rotello, 2007). We presented older and younger adults with emotional and neutral stimuli in a remember-know paradigm. Signal-detection and model-based analyses showed that memory accuracy did not differ for the neutral, negative, and positive stimuli, and that "remember" responses did not reflect the use of recollection. However, both age groups showed large and significant response bias effects of emotion: Younger adults tended to say "old" and "remember" more often in response to negative words than to positive and neutral words, whereas older adults responded "old" and "remember" more often to both positive and negative words than to neutral stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Corrosion mechanisms in ADI parts

The objective of this research is to study the influence of microstructure and grinding on the corrosion resistance of ADI in salt water. Immersion and electrochemical tests were performed on samples austempered at two different temperatures and ground. The results indicate that the dissolution rate increases as the nodule count does, and it is also affected by the microstructure and by the surface changes introduced during grinding. A porous layer is formed on ADI-corroded surface due to the selective dissolution of ferrite, and a preferential dissolution of the matrix around graphite is noticeable. Ground surfaces are less corrosion resistant than polished ones.     

Altered Secretome of Diabetic Monocytes Could Negatively Influence Fracture Healing—An In Vitro Study

Diabetes mellitus is a main risk factor for delayed fracture healing and fracture non-unions. Successful fracture healing requires stimuli from different immune cells, known to be affected in diabetics. Especially, application of mononuclear cells has been proposed to promote wound and fracture healing. Thus, aim was to investigate the effect of pre-/diabetic conditions on mononuclear cell functions essential to promote osteoprogenitor cell function. We here show that pre-/diabetic conditions suppress the expression of chemokines, e.g., CCL2 and CCL8 in osteoprogenitor cells. The associated MCP-1 and MCP-2 were significantly reduced in serum of diabetics. Both MCPs chemoattract mononuclear THP-1 cells. Migration of these cells is suppressed under hyperglycemic conditions, proposing that less mononuclear cells invade the site of fracture in diabetics. Further, we show that the composition of cytokines secreted by mononuclear cells strongly differ between diabetics and controls. Similar is seen in THP-1 cells cultured under hyperinsulinemia or hyperglycemia. The altered secretome reduces the positive effect of the THP-1 cell conditioned medium on migration of osteoprogenitor cells. In summary, our data support that factors secreted by mononuclear cells may support fracture healing by promoting migration of osteoprogenitor cells but suggest that this effect might be reduced in diabetics.     

Hydrophobic Nanoreactor Soft‐Templating: A Supramolecular Approach to Yolk@Shell Materials

Due to their unique morphology‐related properties, yolk@shell materials are promising materials for catalysis, drug delivery, energy conversion, and storage. Despite their proven potential, large‐scale applications are however limited due to demanding synthesis protocols. Overcoming these limitations, a simple soft‐templated approach for the one‐pot synthesis of yolk@shell nanocomposites and in particular of multicore metal nanoparticle@metal oxide nanostructures (M_NP@MO_x) is introduced. The approach here, as demonstrated for Au_NP@ITO_TR (ITO_TR standing for tin‐rich ITO), relies on polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) inverse micelles as two compartment nanoreactor templates. While the hydrophilic P4VP core incorporates the hydrophilic metal precursor, the hydrophobic PS corona takes up the hydrophobic metal oxide precursor. As a result, interfacial reactions between the precursors can take place, leading to the formation of yolk@shell structures in solution. Once calcined these micelles yield Au_NP@ITO_TR nanostructures, composed of multiple 6 nm sized Au NPs strongly anchored onto the inner surface of porous 35 nm sized ITO_TR hollow spheres. Although of multicore nature, only limited sintering of the metal nanoparticles is observed at high temperatures (700 °C). In addition, the as‐synthesized yolk@shell structures exhibit high and stable activity toward CO electrooxidation, thus demonstrating the applicability of our approach for the design of functional yolk@shell nanocatalysts.     

Trends in Water Clarity of the Lower Great Lakes from Remotely Sensed Aquatic Color

Satellite observations of aquatic colour enable environmental monitoring of the Great Lakes at spatial and temporal scales not obtainable through ground-based monitoring. By merging data from the Coastal Zone Color Scanner (CZCS) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), monthly binned images of water-leaving radiance over the Great Lakes have been produced for the periods 1979–1985 and 1998–2006. This time-series can be interpreted in terms of changes in water clarity, showing seasonal and inter-annual variability of bright-water episodes such as phytoplankton blooms, re-suspension of bottom sediments, and whiting events. Variations in Secchi disk depth over Lakes Erie and Ontario are predicted using empirical relationships from coincident measurements of water transparency and remotely-sensed water-leaving radiance. Satellite observations document the extent to which the water clarity of the lower Great Lakes has changed over the last three decades in response to significant events including the invasion of zebra mussels. Results confirm dramatic reductions in Lake Ontario turbidity in the years following mussel colonization, with a doubling of estimated Secchi depths. Evidence confirms a reduction in the frequency/intensity of whiting events in agreement with suggestions of the role of calcium uptake by mussels on lake water clarity. Increased spring-time water clarity in the eastern basin of Lake Erie also corroborates previous observations in the region. Despite historical reports of localised increases in transparency in the western basin immediately following the mussel invasion, image analysis shows a significant increase in turbidity between the two study periods, in agreement with more recent reports of longer term trends in water clarity. Through its capacity to provide regular and readily interpretable synoptic views of regions undergoing significant environmental change, this work illustrates the value of remotely sensing water colour to water clarity monitoring in the lower Great Lakes.     

Sources of social support and burnout, job satisfaction, and productivity.

Social support has been identified as an important correlate of a variety of work outcomes. Support from different sources, including family, coworkers, and supervisors, was examined in 211 traffic enforcement agents (92 men, 119 women). Outcomes included subjective variables (burnout and job satisfaction) and an objective measure of productivity (number of summonses). Support was negatively associated with burnout and positively associated with satisfaction and productivity. A cluster of support variables accounted for 7% of the variance in burnout and productivity and 12% of the variance in job satisfaction. Family support was more closely associated with burnout than with satisfaction or productivity, whereas immediate supervisor support was related to satisfaction and productivity but not burnout. Results suggest that support may be associated with work-related outcomes through multiple pathways. (PsycINFO Database Record (c) 2010 APA, all rights reserved)