Reflection interference contrast

The interest in vesicles as models for cell biomembranes has led to much work on the interactions within and between lipid layers. The primary contributions to vesicle stability and curvature include those familiar to us already, the electrostatic interactions between charged head groups (Chapter V) and the van der Waals interaction between layers (Chapter VI). An additional force due to thermal fluctuations in membranes produces a steric repulsion between membranes known as the Helfrich or undulation interaction. This force has been quantified by Sackmann and co-workers using reflection interference contrast microscopy to monitor vesicles weakly adhering to a solid substrate [78]. Membrane fluctuation forces may influence the interactions between proteins embedded in them [79]. Finally, in balance with these forces, bending elasticity helps determine shape transitions [80], interactions between inclusions [81], aggregation of membrane junctions [82], and unbinding of pinched membranes [83]. Specific interactions between membrane embedded receptors add an additional complication to biomembrane behavior. These have been stud-... 

Schindl, M., WaUraff, E., Deubzer, B. et al. (1995). Cell-substrate interactions and locomotion of Dictyostelium wild-type and mutants defective in three cytoskeletal proteins a study using quantitative reflection interference contrast microscopy. Biophys. ]. 68, 1177-1190. 

Alternatively to force-based approaches, cell adhesion can be quantified by measuring the intersurface distance between the cell and a planar transparent substrate (Fig. 4.30). Reflection interference contrast microscopy (RICM) is ideally suited for studying cell adhesion characteristics and dynamics in aqueous environment, as it allows for nanometer precise determination of intersurface distances with milliseconds time resolution [62]. It has the added... 

FIGURE 4.30 Optical principle of reflection interference contrast microscopy (RICM). The optical path (a) and the formation of constructive and destractive interference with the resulting reference pattern (b) are depicted on Ref. 61. 

Figure 2.24 Schematic presentation of the direct, as well as inhibition-competition, assay using soft colloidal probes and their analysis via reflection interference contrast microscopy, adapted from Pussak et al. ...

Observation of the Contact Reflection Interference Contrast Microscopy... 

The experimental setup relies on a reflection interference contrast microscope (RICM) used in conjunction with a CCD camera and a video camera recorder (VCR). 

FIGURE 9.24. Principle of the reflection interference contrast microscopy (RICM) technique. 

Reflected light differential interference contrast (DIC), 16 482 Reflection correction algorithms, 24 456 Reflection high-energy electron diffraction (RHEED), 24 74 Reflection indexing... 

The colour interference contrast image is achieved via special experimental conditions, which comprise the angle of the incident light, wavelength of the light of the reflected ray, chemical composition, thickness and refractive index of a sample, and refractive index and chemical composition of a substrate. 

Figure 12.1. Elemental spiral step patterns observed on the 0001 face of beryl, (a) Low magnification, reflection (b) high magnification, differential interference contrast photomicrograph.

Suci et al. [918] have demonstrated that the possibilities of ATR can be extended by combining the method with reflected differential interference contrast spectroscopy. It was shown that such an approach allows the biofihn structure, distribution, and chemistry at solid-liquid interfaces to be investigated simultaneously, the data being obtained in situ, quasi-simultaneously, nondestructively, and in real time. 

The Nomarski differential interference contrast technique accentuates changes in specimen thickness and refractive index in transmission without giving the haloes round fine features that distract from the usefulness of the phase-contrast technique. In reflection, images are obtained that strongly accentuate the topographical features present. 

Calculated hardness values are not affected to any significant degree by the presence of cracks. Large variations in hardness values may be caused by the presence of pores, inclusions of other ceramic phases, or by the crystallographic orientation. Indentations in transparent materials are difficult to measure. In these cases, it is advisable to apply a thin, highly reflective film of gold by means of sputtering or to use the differential interference contrast (DIC) method. 

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