An experimental UHV AFM-STM device for characterizing surface nanostructures under stress/strain at variable temperature.

A compression setup fully integrated in an ultra high vacuum chamber is presented. The system has been designed to combine in situ mechanical test together with near field microscopy at variable temperature, from 90 to 600 K. Compressive stress can be applied on the samples up to 500 MPa at different strain rates ranging from 10(-6) s(-1) to 10(-2) s(-1). The setup performances are highlighted through investigations on Au and Ni3(Al,Ta) single crystals. In particular, it is demonstrated that the high mechanical stability of the original apparatus allows us to follow in situ the evolution of the same area of interest over a large range of temperature and to keep the high spatial resolution offered by near field microscopy, even at high strain levels.

Adhesion Forces between Lewis(X) Determinant Antigens as Measured by Atomic Force Microscopy.

The adhesion forces between individual molecules of Lewis(X) trisaccharide antigen (Le(X) ) have been measured in water and in calcium solution by using atomic force microscopy (AFM, see graph). These results demonstrate the self-recognition capability of this antigen, and reinforce the hypothesis that carbohydrate-carbohydrate interaction could be considered as the first step in the cell-adhesion process in nature.