High precision densitometry of small specimen

Abstract

Li et al., [26] is as follows: The grain boundaries in UFG as well as in nanocrystalline materials will act as very effective sources and sinks for dislocations. Due to the relatively small grain size, reactions between mobile dislocations and grain boundary dislocations are very likely to occur. Thermally activated annihilation processes in the grain boundaries, which are still active at relatively low homologous temperatures, might therefore play a decisive role for the increasing ductility as the deformation rate decreases, although the homologous temperatures are rather low. Further investigations are planned in order to clarify this very important issue for understanding the paradox of strength and ductility.

A silicon‐based multi‐sensor chip for monitoring of fermentation processes

“…Besides temperature, pressure and oxygen content, the pH value is the most frequently monitored parameter during a fermentation process as enzymatic activity and, thereby the complete metabolism is susceptible to pH variations 12. In industrial fermentation plants and in lab‐scale fermenters, pH monitoring by means of pH glass electrodes remains state‐of‐the‐art 5. However, as further miniaturization and parallelization of bioprocesses become more and more important, alternative monitoring devices are needed.…”

“…Since cell growth and production rate have a strain‐dependent distinct temperature optimum, the temperature should be maintained during the process and thus needs to be monitored 5. Furthermore, the measurement of electrolyte conductivity has to be compensated for influences of temperature and referred to a standard temperature to be comparable 22.…”

“…However, cellular systems are still poorly understood due to a lack of suited sensor systems matching the stringent conditions for bioprocess monitoring. In practice, temperature, pH value, dissolved oxygen concentration and the exhaust gas composition are the most widely measured and controlled in situ parameters 4, 5. Even though vigorous research has been conducted, bioprocess optimization remains expensive and labor‐intensive as manifold experiments have to be performed.…”

Concept for a solid-state multi-parameter sensor system for cell-culture monitoring

“…Sensors for these parameters are typically inserted into specially designed ports on the vessel. Steam-sterilisable glass electrodes remain state-of-the-art for use in bioprocesses [1,5]. However, they suffer from low mechanical stability and are not useful in small-sized bioreactors.…”

Point-of-Care Assay of Telomerase Activity at Single-Cell Level via Gas Pressure Readout

“…Gas pressure is a very familiar physical parameter, and pressure measurements are widely used in industry. 23 However, bioanalysis based on measurement of gas pressure is very rare. Yang's group has creatively used platinum nanoparticles (PtNPs) to catalyze the decomposition of H 2 O 2 and generate O 2 for immunoassay.…”