The color stability of polyvinyl chloride, polyurethane, and silicone polymers for maxillofacial applications was determined after accelerated aging using reflectance spectrophotometry. On the basis of color stability after accelerated aging, and ease of processing, several silicone materials were the most promising.

Soybean seeds which had aged in long-term storage ("natural aging") or by exposure to high temperature and humidity ("accelerated aging") were analyzed for their tocopherol and organic free radical contents. Tocopherol levels remained unchanged during both types of aging. Three principal tocopherol homologues (alpha, gamma, delta) were present in fairly constant proportions throughout. Organic ...

Past works showed that the degradation of the passive devices caused by aging could induce failures of electronic system, including a harmful evolution of electromagnetic compatibility. This paper presents the impact of accelerated aging conditions on several typical passive components (capacitor, inductor). The preliminary degradation models of electrolytic capacitor and powder iron inductor a...

Alterations in the architecture and dynamics of the nuclear lamina have a causal role in normal and accelerated aging through both cell-autonomous and systemic mechanisms. However, the precise nature of the molecular cues involved in this process remains incompletely defined. Here we report that the accumulation of prelamin A isoforms at the nuclear lamina triggers an ATM- and NEMO-dependent si...

Glia Maturation Factor-β (GMF), a brain specific protein, is induced by proteinuria in renal tubules. Ectopic GMF overexpression causes apoptosisin vitro via cellular vulnerability to oxidative stress. In order to examine the roles of GMF in non-brain tissue, we constructed transgenic mice overexpressing GMF (GMF-TG). The GMF-TG mice exhibited appearance phenotypes associated with premature agi...

Over the past three decades, supernovae observations have been the primary tool used in measuring both the current expansion rate and the expansion history of the universe. Supernovae are preferred because they are the best known standard candle and they can be observed in the early and recent universe. But because they are rare and unpredictable, they are difficult to measure. In the late 1990...

Initial estimates of aggregate output and its components are based on very incomplete source data, so they may not fully capture shifts in economic conditions. In particular, if those estimates are based partly on trends in preceding quarters, one would expect to see provisional estimates overstating activity when actual output is decelerating and understating it when actual output is accelerat...

The unexpected dimness of Type Ia supernovae at redshifts z . 1 has over the past 7 years been seen as an indication that the expansion of the universe is accelerating. A new model cosmology has been proposed by one of us (Wiltshire 2005), based on the idea that our observed universe resides in an underdense bubble remnant from a primordial epoch of cosmic inflation. Although there is no cosmic...

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A rational approach to the problem of accelerated testing of high temperature polymeric composites is discussed. The methods provided are considered tools useful in the screening of new materials systems for long-term application to extreme environments that include elevated temperature, moisture, oxygen, and mechanical load. The need for reproducible mechanisms, indicator properties, and real-...