Noninvasive in situ, techniques

Measurement techniques for the resolution of concentration and temperature profiles in chemical reactors with heterogeneously catalyzed gas-phase reactions are a very useful tool not only for a better understanding of the reaction sequence and derivation of reaction kinetics but also for the elucidation of the coupling between catalytic reaction kinetics and mass and heat transport. The combination of numerical simulations of the reactive flow in catalytic reactors incorporating microkinetic reaction schemes and those recently developed invasive and noninvasive in situ techniques can today support the optimization of reactor design and operating conditions in industrial applications. 

In order to relate material properties with plasma properties, several plasma diagnostic techniques are used. The main techniques for the characterization of silane-hydrogen deposition plasmas are optical spectroscopy, electrostatic probes, mass spectrometry, and ellipsometry [117, 286]. Optical emission spectroscopy (OES) is a noninvasive technique and has been developed for identification of Si, SiH, Si+, and species in the plasma. Active spectroscopy, such as laser induced fluorescence (LIF), also allows for the detection of radicals in the plasma. Mass spectrometry enables the study of ion and radical chemistry in the discharge, either ex situ or in situ. The Langmuir probe technique is simple and very suitable for measuring plasma characteristics in nonreactive plasmas. In case of silane plasma it can be used, but it is difficult. Ellipsometry is used to follow the deposition process in situ. 

There are several new in situ soil carbon measurement techniques undergoing field testing. Some devices, such as those using a neutron generator, measure total C atoms to a known depth, and as a result do not require a bulk density measurement (L. Wielopolski, personal communication, March 2007). In addition, such in situ and noninvasive techniques would allow the same location to be measured repeatedly. However, for the time being, and likely for many applications in the future, the importance of carefully measuring bulk density cannot be overstated. 

Spectroscopy-based noninvasive analysis for any of the clinical applications noted above provides a means to collect critical analytical information in a novel fashion compared to competing technologies. Alternatively, implants can be used, but operation of implanted sensors is confounded by biologic responses that degrade performance and demand in situ calibration techniques. 

Milne et al. [154] have developed stereotactically guided laser thermotherapy for breast cancer in situ measurements. They determine the temperature field within the breast to highlight potential tumors. A review paper by Tromberg et al. [155] discusses the noninvasive in vivo characterization of breast cancer tumors using photon migration spectroscopy. They compare the use of this technique with straightforward NIR spectroscopy. 

TIRF occupies a unique niche, providing a noninvasive method for studying protein adsorption in situ and in real time. The TIRF technique, as it is applied in our laboratory, has been used successfully to study both macroscopic and molecular aspects of protein adsorption. The present goal of this laboratory is to elucidate the interactions occurring when a protein adsorbs to a solid surface using the TIRF technique. It is hoped that, eventually, a complete, general description of the protein adsorption process will be attained. 

The ability of the noninvasive TDS technique to analyze in situ the properties of the intracellular structures is very important. If indeed the two-shell model represents also the NE and the nucleoplasm, then it describes the very regions of the cell where the putative control of cell division resides, and also the region where the gene expression takes place. Electrical methods are relatively easy to apply (72, 214) and can lead flic molecular biologist to decipher more... 

In vivo NMR spectroscopy has enabled the investigation and monitoring of metabolic changes in living tissues in situ. Unlike many other biochemical techniques, it is noninvasive, facilitating studies on previously inaccessible tissues such as the brain. 

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