Glass water interface

Fig. 1 Real-time tracking of cell adhesion [42]. (a) Components of a total internal reflection fluorescent microscope (TIRFM). (b) The cell adhesion process (7) a cell approaches the surface, (2) the cell lands, (3) the cell attaches, and (4) the cell spreads out on the surface. The evanescent field was generated by total internal reflection of a laser beam at the glass-water interface. Cells with fluorescently labeled membranes (dashed lines) were plated on SAMs. Cell membranes within the evanescent field (solid line) were observed by TIRFM. Corresponding TIRFM images are shown below...

For a bare glass/water interface, this criterion is... 

Some of these difficulties can be traced to unproven, and perhaps incorrect, assumptions implicit within the Aagaard Helgeson (1982) model. For example, reaction rates at the glass/ water interface are modelled as sequential. As we discuss below, there is good reason to consider reactions as taking place concurrently. In a system that is close to equilibrium, the identity of the dominant dissolution mechanism among a set of concurrent elementary reactions may change as conditions shift. Another potential pitfall is the assumption that the principle of... 

Fig. 6.9. A Spontaneous Raman spectrum of d62-DPPC lipids and its decomposition into Lorentzian line profiles. B Normalized multiplex CARS spectra (dots) of a planar-supported bilayer and monolayer formed by d62-DPPC on a glass-water interface for parallel-polarized input beams, together with the fit using the center frequency and line width parameters extracted from the decomposition analysis in (A) (solid line). The spectrum exposure time was 0.64 s. Error bars indicate the shot-noise standard deviation (Copyright American Chemical Society [70])...

The contact angle between water and glass is increased considerably by even less than an adsorbed monolayer of greasy material such as fatty acid. Wa is decreased, since some of the glass-water interface is replaced by hydrocarbon-water interface (Figure 6.4a) hence, from the Young-Dupr6 equation, 0 increases. 

Calculate the rate of electro-osmotic flow of water at 25°C through a glass capillary tube 10 cm long and 1 mm diameter when the potential difference between the ends is 200 V. The zeta potential for the glass-water interface is -40 mV. 

A glass particle suspended in water (tj = 0.01 poise) was observed to move with a velocity of 21.0 X 10 cm. per sec. under a potential gradient of 6.0 volts per cm. Calculate the zeta-potential at the glass-water interface. 

From the materials point of view the surface of a solid can in a simple way be defined as a discontinuity in a lattice pattern. More precisely, a discontinuity in a lattice pattern is an interface. For example, the surface of a metal in a vacuum should be called the solid/ vacuum interface. The inner surface of a glass fish bowl filled with water should be called the glass/water interface. When we designate the interface simply as the surface of the solid we usually presume that what exists on the other side of the interfacial boundary has no effect on the solid at the interface. Sometimes this assumption is valid insofar as can be detected at other times the "environment" does affect the properties of the solid side of the interface. 

Fig. 3 Behavior of the penetration depth d normalized by the incident wavelength Xq as a function of the incident angle 6i for a typical glass-water interface with n = 0.878...

Crucial in the design of the instrument is the focusing control for the microscope objective. For TIRF applications it is necessary to place the centre of the depth of focus of the objective (the objective focal plane) near the glass water interface. For diffusion confocal and two-photon designs it is desirable to always... 

Haber developed a model and a theory that explained the forces developed by acids and bases at the boundaries of electrolytically conducting aqueous phases. Haber s "conceptualization" for the glass water interface envisioned, as reported in the thesis of Hans Schiller, ) was... 

Oddy and Santiago used micro-PIV techniques to study small particles in AC and DC electro-osmotic flow [10]. Independent measurements of the particle motion in the two fields can be correlated to determine the electrophoretic mobility of the particle and electro-osmotic mobility of the solid-liquid interface. The electrophoretic mobility of the fluorescent polystyrene particles was found to be —3.76 ib 0.05 pm cm/Vs and the zeta potential of the glass/water interface for a pH of 7 was — 115 zb 10 mV. 

At the edge between 6a and 6c, the laser beam is incident above critical angle at the glass/water interface at where the beam is totally internally reflected, generating evanescent field in the water. Thus, by shifting the position of the one mirror, the type of illumination can be switched between epi-fluorescence microscopy and objective-type TIRFM. 

Figure 3 compares the power collection efficiency of two optical collection schemes, system I, a trans-illumination scheme and system II, an epi-illumination scheme. The power collection efficiency is computed with respect to system 0 gathering the power Pq from a randomly oriented fluorophore located at a distance z > 0 from a glass-water interface using a 1.20NA water immersion objective positioned at z<0. The dotted line describes the fluorescence power Pi collected by system I, consisting of a 1.20NA water... 

Figure 2. Anisotropic dipole radiation profile modeling a fluorophore at a glass-water interface. The critical angle is indicated by straight lines. Depending on distance and dipole orientation, this radiation profile shows a pronounced anisotropy and asymmetry.

---