Syngas generation from n-butane with an integrated MEMS assembly for gas processing in micro-solid oxide fuel cell systems.

An integrated system of a microreformer and a carrier allowing for syngas generation from liquefied petroleum gas (LPG) for micro-SOFC application is discussed. The microreformer with an overall size of 12.7 mm × 12.7 mm × 1.9 mm is fabricated with micro-electro-mechanical system (MEMS) technologies. As a catalyst, a special foam-like material made from ceria-zirconia nanoparticles doped with rhodium is used to fill the reformer cavity of 58.5 mm(3). The microreformer is fixed onto a microfabricated structure with built-in fluidic channels and integrated heaters, the so-called functional carrier. It allows for thermal decoupling of the cold inlet gas and the hot fuel processing zone. Two methods for heating the microreformer are compared in this study: a) heating in an external furnace and b) heating with the two built-in heaters on the functional carrier. With both methods, high butane conversion rates of 74%-85% are obtained at around 550 °C. In addition, high hydrogen and carbon monoxide yields and selectivities are achieved. The results confirm those from classical lab reformers built without MEMS technology (N. Hotz et al., Chem. Eng. Sci., 2008, 63, 5193; N. Hotz et al., Appl. Catal., B, 2007, 73, 336). The material combinations and processing techniques enable syngas production with the present MEMS based microreformer with high performance for temperatures up to 700 °C. The functional carrier is the basis for a new platform, which can integrate the micro-SOFC membranes and the gas processing unit as subsystem of an entire micro-SOFC system.

Load sensing surgical instruments.

Force and pressure sensing technology applied to smart surgical instruments as well as implants allow to give a direct feedback of loads to the surgeon lead to better reliability and success of surgical operations. A common technology used for sensors is low-cost piezoresistive thick-film technology. However, the standard thick-film firing conditions degrade the properties of medical alloys. In order to avoid this problem, the solution is to decrease the firing temperature of thick films. This work presents the development and characterisation of low-firing thick-film systems (dielectrics, resistors and conductors), formulated to achieve chemical and thermal expansion compatibility with an austenitic stainless steel medical alloy. Adherence tests and results on electrical properties of these systems: resistance, temperature coefficient of resistance (TCR) are presented. It was found that the main issue in these systems lies in mastering the materials interactions during firing, especially at the silver-based resistor terminations. The interaction of silver, resistor and dielectric tends to give rise to highly resistive zones at the terminations, affecting reliability. This can be circumvented by post-firing the resistor terminations at a moderate temperature.

A spermine-coupled cholesterol metabolite from the shark with potent appetite suppressant and antidiabetic properties.

OBJECTIVE: We describe the pharmacological properties of a novel spermine-cholesterol adduct, MSI 1436 (3beta-N-1(spermine)-7alpha, 24R-dihydroxy-5alpha-cholestane 24-sulfate), which causes reversible suppression of food and fluid intake in mammals resulting in profound weight loss, not associated with other signs or symptoms of illness, and which exhibits antidiabetic properties in genetically obese mice. METHODS: Wild-type rodents and strains with genetic obesity were studied. Effects on food and fluid intake, body weight and composition were examined along with pharmacological and toxicological parameters. RESULTS: MSI-1436 induces profound inhibition of food and fluid intake in rats and mice, resulting in significant weight loss. MSI-1436 is active when introduced directly into the third ventricle of the rat, suggesting the compound acts on central targets. Pair-feeding studies suggest that MSI-1436 causes weight loss by suppressing food intake. Fluid intake is also profoundly reduced but animals remain normally hydrated and defend both water and electrolyte balance from parenteral administration. MSI-1436 is active in ob/ob, db/db, agouti and MC4 receptor knockout mice. MSI-1436 has been administered to ob/ob mice over a 4 month period via a regimen that safely controls body weight, glucose homeostasis and serum cholesterol levels. Following MSI-1436 treatment, db/db mice preferentially mobilize adipose tissue and hyperglycemia is corrected. CONCLUSION: A naturally occurring spermine metabolite of cholesterol, isolated from the dogfish shark, Squalus acanthias, has been identified that induces profound reduction in food and fluid intake in rodents in a setting where thirst is preserved and fluid and electrolyte homeostasis appears to be functioning normally. MSI-1436 probably acts on a central target involving neural circuits that lie downstream from the leptin and the MC4 receptors. Although long-term administration can be accomplished safely in mice, the utility of this compound as a potential human therapeutic awaits an analysis of its pharmacological properties in man.