Optical/chemical micro-methods

Micro flow control devices open new possibilities for the miniaturization of conventional chemical and biochemical analysis systems. The micro total analysis system (pTAS) including microfabricated detectors (e.g. silicon based chemical sensors, optical sensors), micro flow control devices and control/detec-tion circuits is a practical micro electro mechanical system (MEMS). pTAS realize very small necessary sample volume, fast response and the reduction of reagents which is very useful in chemical and medical analysis. Two approaches of monolithic and hybrid integration of these devices have been studied. Monolithic and hybrid types of flow injection analysis (FIA) systems were already demonstrated [4, 5]. The combination of the partly integrated components and discrete components is useful in many cases [6]. To fabricate such systems, bonding and assembling methods play very important roles [7]. 

The sulfite reaction is used for the above-mentioned purpose and hence is an analytical tool for judging micro-reactor performance [5,9,10]. The sulfite oxidation as a chemical method provides complementary information to optical analysis of the specific interfacial area. 

In general, optical-based pH measurement techniques require relatively expensive and cumbersome instruments, and their sophisticated method cannot be easily carried out for routine assay. Interfering contact and reactions of the dye molecules, particularly considering in-vivo measurements, cannot be excluded [34], Some other possible factors, such as a weaker signal at shorter response times, complications in microfabrication, and difficulties in attaching the chemical or biological agents to the small fiber tip, are potential limitations for the application of these optical sensors to in-vivo measurements in micro environments [35]. 

Some of the technological areas in which means and methods of electrochemical deposition constitute an essential component are all aspects of electronics—macro and micro, optics, optoelectronics, and sensors of most types, to name only a few. In addition, a number of key industries, such as the automobile industry, adopt the methods even when other methods, such as evaporation, sputtering, chemical vapor deposition (CVD), and the like, are an option. That is so for reasons of economy and/or convenience. 

Optical absorption spectra were measured using the glass and composite samples of 2-4 mm thickness in the IR, visible- and UV-regions. The pore-size distribution in the gel structure measured by BET-method has a complex character the network contains micro- (3.0 nm), meso- and macro-pores (5-25 nm). The pore size can be increased by chemical attack of silica network by fluorine ions in solution and also in vapor phase until heating and dissociation of F-containing compounds (HF, NH4F). 

Bertsch PM, Seaman JC (1999) Characterization of complex mineral assemblages Implications for contaminant transport and environmental remediation. Proc Nat Acad Sci 96 3350-3357 Bertsch PM, Hunter DB, Sutton SR, Bajt S, Rivers ML (1994) In situ chemical speciation of uranium in soils and sediments by micro X-ray absorption spectroscopy. Envir Sci Techno 28 980-984 Bildeiback DH, Huang R (2001) X-ray tests of microfocusing mono-capillary optic for protein crystallography. Nucl Instrum Methods Phys Res A 467-468 954-967 Bilderback DH, Thiel DJ (1995) Microbeam generation with capillary optics. Rev Sci Instrum 66 2059-2063... 

No convincing conclusion has been reached as to the biodegradation mechanisms of bioactive ceramics. Many researchers have reported different results, as described above. These discrepancies are considered to be caused by the fact that materials used for the experiments were different, and that experimental methods and analytical methods were also different. Therefore, when these reported results are compared, it is important to consider the characteristics of the material used (chemical compositions, impurity, crystallinity, dense or porous, micro- or macro-porous, porosity), experimental methods used in vivo or in vitro, animal species, implanted duration, implanted sites, load bearing or not), and analytical methods used (radiographic, optical microscopic, electron microscopic). Futhermore, a good understanding of the characteristics of the materials to be used becomes important when bioactive ceramics are used clinically. 

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