Anisotropy polarization

Jonas D M, Lang M J, Nagasawa Y, Joo T and Fleming G R 1996 Pump-probe polarization anisotropy study of femtoseoond energy transfer within the photosynthetio reaotion-oenter of Rhodobacter sphaeroides R26 J. Rhys. 

The fluorescence depolarization technique excites a fluorescent dye by linearly polarized light and measures the polarization anisotropy of the fluorescence emission. The fluorescence anisotropy, r, is defined as... 

Fluorescence polarization anisotropy of a ligand and its complexes with DNA or RNA can be given by the following expression ... 

Piquemal J-P, Chelli R, Procacci P, Gresh N (2007) Key role of the polarization anisotropy of water in modeling classical polarizable force fields. J Phys Chem A 111 8170... 

L.M. Herz and R.T. Phillips, Effects of interchain interactions, polarization anisotropy, and photo-oxidation on the ultrafast photoluminescence decay from a polyfluorene, Phys. Rev. B, 61 13691-13697, 2000. 

Figure 9. Experimental [59] and theoretical values of the polarization anisotropy time correlation function at 100 fs, as a function of OD stretch frequency, for three different temperatures. See color insert.

Photon echo and IR pump-probe experiments can also be performed on neat water, but one needs a very small sample. Fabrication of nano-fluidic Si3Ni4 sample cells have opened up this new and exciting field, and data from these experiments, performed by the Elsaesser and Miller groups, have recently been reported [73, 74]. At room temperature, spectral evolution occurs within 50 fs, and polarization anisotropy decays within 75 fs. At temperatures just about the freezing point, spectral evolution slows down dramatically [74],... 

Figure 21.8 The dynamics of the polarization anisotropy for the Au(0) i emission. The temporal profiles of the emission in the parallel plane (dashed line) and the plane perpendicular (dotted line) to the polarization of the excitation pulse are also shown.

The broad field of nucleic acid structure and dynamics has undergone remarkable development during the past decade. Especially in regard to dynamics, modem fluorescence methods have yielded some of the most important advances. This chapter concerns primarily the application of time-resolved fluorescence techniques to study the dynamics of nucleic acid/dye complexes, and the inferences regarding rotational mobilities, deformation potentials, and alternate structures of nucleic acids that follow from such experiments. Emphasis is mainly on the use of time-resolved fluorescence polarization anisotropy (FPA), although results obtained using other techniques are also noted. This chapter is devoted mainly to free DNAs and tRNAs, but DNAs in nucleosomes, chromatin, viruses, and sperm are also briefly discussed. 

Figure 4.1. Time scales for rotational motions of long DNAs that contribute to the relaxation of the optical anisotropy r(t). Experimental methods used to study these motions in different time ranges are also indicated along with the authors and dates of some early work in each case. FPA, Fluorescence polarization anisotropy (Refs. 15, 18-20, and 87) TPD, transient photodichroism (Refs. 28 and 62) TEB, transient electric birefringence (Refs. 26 and 27) DDLS, depolarized dynamic light scattering (Ref. 116) TED, transient electric dichroism (Refs. 25, 115, and 130) Microscopy, time-resolved fluorescent microscopy (Ref. 176).

Srebrodolski and Yushkin tested 14 brimstone crystals for hardness anisotropy and plotted from the data (Table 7.1) hardness rosettes for four crystal faces (Fig. 7.3). Apart from finding the normal anisotropy of 2nd order from the hardness ratio determined on two faces, they also determined the polar anisotropy of 1st order on each of the faces under test. 

It follows from WinchelPs data that change in orientation of the indenter on the (111) face also results in differences due to polar anisotropy, equalling -KtfCaFjUll) — 1.1. 

Crystallographic orientation Hardness 77v Polar anisotropy coefficient 77m a. jKh = TTmln Anisotropy ceofficient Mean hardness ... 

Thomas, J. C., Allison, S. A., Appellof, C. J., and Schurr, J. M. (1980). Torsion dynamics and depolarization of fluorescence of linear macromolecules. II. Fluorescence polarization anisotropy measurements of a clean viral phi 29 DNA. Biophys. Chem. 12, 177-188. 

Polarization of the CMB was shown to be < 300 fiK (Lubin and Smoot, 1981). This observation used a differential polarimeter that was only sensitive to linear polarization. COBE put a limit of < 15 fiK on the polarization anisotropy. The linear polarization of the CMB was first detected by DASIPOL (Kovac et al., 2002), and the cross-correlation of the temperature and polarization anisotropies was confirmed by WMAP (Kogut et al., 2003). 

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