Laser adhesive technique

Microdissection via the laser adhesive technique may be a solution to this plight (Banks et al. 1999). The tissue sample (e.g., the punctate) is cut into slices with the microtome and the slices are stained with hematoxylin and eosin. You lay the stained cut on a glass plate and push it under an inverted microscope. Now you identify the tumor and lay a little tube on the interesting area. The bottom of the little tube is sealed with a UVA polymer film. The film thus touches the tissue. Now the cancerous parts of the tissue are glued to the film. This is done with a laser beam directed at the desired areas. Once the adhesion is complete, you take the little tube off, with film and the tissue that is stuck to it. The rest of the cut remains on the glass plate. Now the little tube is put on an Eppendorf cup like a lid. In the cup there is sample buffer. If you turn the cup aroimd, the sample buffer loosens the protein from the film (Figure 7.3). 

In any case, the method has one problem per slice you get minute amounts of protein. This means you have to stain, inspect, glue, and extract many, many slices. Rosamonde Banks needed 13 h (without a break ) to prepare enough protein for a 2D gel. Many doctorate students or TAs would probably not have a similar stamina. The team leaders who want to use the laser adhesive technique as a standard method will have to invest a substantial share of their research money into help-wanted ads in lab journals. 

V. Gupta, J. Yuan, A. Pronin, Recent Developments in the Laser Spallation Technique to Measure the Interface Strength and Its Relationship to Interface Toughness with Applications to Metal/Ceramic, Ceramic/ Ceramic and Ceramic/Polymer Interfaces, in K.L. Mittal (Ed.), Adhesion Measurement of Films and Coatings, VSP BV Publishers, 1995, p. 367. 

Another approach is to coat the cutting tool material with a carbide former, such as titanium or siUcon or their respective carbides by CVD and deposit diamond on top of it. The carbide layer may serve as an iaterface between diamond and the cemented carbide, thus promoting good bonding. Yet another method to obtain adherent diamond coatings is laser-iaduced microwave CVD. By ablating the surface of the substrate with a laser (typically, ArF excimer laser) and coating this surface with diamond by microwave CVD, it is possible to improve the adhesion between the tool and the substrate. Partial success has been achieved ia this direction by many of these techniques. 

Buchman, A. and Dodiuk-Kening, H., Laser surface treatment to improve adhesion. In Mittal, K.L. and Pizzi, A. (Eds.), Adhesion Promotion Techniques — Technological Applications. Dekker, New York, 1999, pp. 205-244. 

Laser diffraction is a fast alternative for analysis of the size distribution of particles in an aerosol cloud. The theory of laser diffraction is well understood [124,125]) but this technique requires special measures to test inhalation devices and to interpret the results correctly. One of the major problems is that flow adjustment through the inhaler is not possible. Furthermore, the presence of carrier particles from adhesive mixtures may disturb the measurement of the fine drug particles and the size distribution obtained is of an unknown dehvered mass fraction of the dose. These practical problems and limitations have been solved by the design of a new modular inhaler adapter for the Sympatec laser diffraction apparatus (Figure 3.6). 

Other coating processes involving fluoridated apatite have been investigated to improve the long-term adhesion and promote osteointegration of cementless titanium-based metal implants pulsed laser deposition, electron beam deposition and ion beam sputter deposition techniques, and sol-gel methods, for example. They lead to fluor-containing calcium phosphates (apatites in most cases) with different compositions and crystallinity states. 

Understanding particle adhesion to a surface has applications in tissue engineering and particle processing. Experimental techniques for charactering particle adhesion to surfaces include laser trapping, AFM and microscopy with force measurement. 

During the last decade, processing of polymers has become an important field of applied and fundamental research [48]. One of the most important fields is laser ablation involving various techniques and applications. Laser ablation is used as an analytical tool for MALDI (matrix-assisted laser de-sorption/ionization) [28, 29] and LIBS (laser-induced breakdown spectroscopy) [49] or as a preparative tool for PLD (pulsed laser deposition) of inorganic materials [37] and of synthetic polymer films [50, 51]. Another application is surface modification of polymers [52] if low fluences are applied, the polymer surface can be either chemically modified to improve adhesion... 

Alternatively, excimer laser treatment can be used to obtain additional improvement of adhesion. By this technique, polymer layers at the surface can be removed selectively before bonding, thus making the adhesive layer directly hnked to the fiber reinforcement itself Hence, crack propagation which occurs cohesively in the material under this polymer layer can no longer take place. Section 20.3.2 provides the results of such an approach. 

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