Light dependence

The color of the emitted light depends on what type of gas is present. For example, sodium atoms glow with a yellow light (as in the familiar yellow street lights), and neon glow with a dark red light (as in the familiar neon lights). 

Bacterial Photosynthesis A light-dependent, anaerobic mode of metabolism. Carbon dioxide is reduced to glucose, which is used for both biosynthesis and energy production. Depending on the hydrogen source used to reduce COj, both photolithotrophic and photoorganotrophic reactions exist in bacteria. 

For these reasons many research groups prefer to dry the chromatograms in a vacuum desiccator with protection from light. Depending on the mobile phase employed phosphorus pentoxide, potassium hydroxide pellets or sulfuric acid can be placed on the base of the desiccator, to absorb traces of water, acid or base present in the mobile phase. 

FIGURE 22.4 The light-dependent and light-independent reactions of photosynthesis. Light reactions are associated with the thylakoid membranes, and light-independent reactions are associated with the stroma. 

The construction of calibration curves is recommended in nephelometric and turbidimetric determinations, since the relationship between the optical properties of the suspension and the concentration of the disperse phase is, at best, semi-empirical. If the cloudiness or turbidity is to be reproducible, the utmost care must be taken in its preparation. The precipitate must be very fine, so as not to settle rapidly. The intensity of the scattered light depends upon the number and the size of the particles in suspension, and provided that the average size of particles is fairly reproducible, analytical applications are possible. 

The color of light depends on its frequency and wavelength long-wavelength... 

Figure 19. The polychromatic LGS. The laser beam is tilted on its way to the mesosphere, where it produces a spectmm spanning from the UV to the infrared. The optical path of the backscattered light depends on the wavelength.

The results of this study may be helpful to understand the light-dependent photosynthetic activity of H. pluvialis. At the same time, the information presented here can be used for enhancing the volumetric biomass productivity of the astaxanthin-accumulating alga. 

The color of the light depends on the energy loss for the electrons and increases with the size of the band gap of the semiconductor. Thus, red LEDs use semiconductors with relatively small band gaps, whereas... 

Armstrong, G. and Apel, K., Molecular and genetic analysis of light-dependent chlorophyll biosynthesis. Methods EnzymoL, 291, 237, 1998. 

The amount of ventilation required, like the amount of lighting, depends upon the circumstances. Some general rules are given in Table 8-8.44,45 Note that there are several guidelines and that in some instances more than one may apply. When this occurs the requirements for each should be calculated and the maximum rate used. None of these guidelines applies to hazardous areas, where the air may have to be moved more rapidly. Some estimates are given in Table 8-9. Safety guidelines and OSHA (Occupational Safety and Health Act) rules should be consulted under these conditions. 

Wilson LG, Bressan RA, Filner P. 1978. Light-dependent emission of hydrogen sulfide from plants. Plant Physiol 61 184-189. 

While s-polarized radiation approaches a phase change near 180° on reflection, the change in phase of the p-polarized light depends strongly on the angle of incidence [20]. Therefore, near the metal surface (in the order of the wavelength of IR) the s-polarized radiation is greatly diminished in intensity and the p-polarized is not [9]. This surface selection rule of metal surfaces results in an IR activity of adsorbed species only if Sfi/Sq 0 (/i = dipole moment, q = normal coordinate) for the vibrational mode perpendicular to the surface. 

We use optical microscopy to examine samples at magnifications from about 5x up to approximately l,000x. Samples may be examined using either transmitted or reflected light, depending on the nature of the sample and the information that we are seeking. 

Mizuno H, Mai TR, Walchli M, Rikuchi A, Fukano T, Ando R, Jeyakanthan J, Taka J, Shiro Y, Ikura M, Miyawaki A (2008) Light-dependent regulation of structural flexibility in a photochromic fluorescent protein. Proc Natl Acad Sci USA 105 9227-9232... 

Raman spectroscopy is an inelastic light scattering experiment for which the intensity depends on the amplitude of the polarizability variation associated with the molecular vibration under consideration. The polarizability variation is represented by a second-rank tensor, oiXyZ, the Raman tensor. Information about orientation arises because the intensity of the scattered light depends on the orientation of the Raman tensor with respect to the polarization directions of the electric fields of the incident and scattered light. Like IR spectroscopy, Raman... 

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