Transient dichroism

Figure 17 Emission intensity in two channeis for a buik sampie (a) and corresponding iinear dichroism transient (b). Emission intensity in two channeis for a singie moiecuie (c) and the corresponding iinear dichroism transient (d). The biack and the red iine in (a) and (c) represent /p and /s, respectiveiy.

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).

Figure 4.11. Longest bending relax- 200 ation time t, as a function of (W-f-1 )A The symbols are the fast 8Q0 components detected in the off-field transient electric dichroism data of...

The ability of DNA-binding drugs to induce chromatin condensation calls for in-depth studies, because the biological consequence of chromatin condensation is its loss of transcriptional ability. Therefore it might be a mechanism of transcription inhibition by the reversible DNA binders. The first report in this line (Sen and Crothers, 1986) employed transient electric dichroism to study the ability of the drugs to induce folding of chromatin from the 10- to 30-nm fiber either by... 

Optical Spectroscopy General principles and overview, 246, 13 absorption and circular dichroism spectroscopy of nucleic acid duplexes and triplexes, 246, 19 circular dichroism, 246, 34 bioinorganic spectroscopy, 246, 71 magnetic circular dichroism, 246, 110 low-temperature spectroscopy, 246, 131 rapid-scanning ultraviolet/visible spectroscopy applied in stopped-flow studies, 246, 168 transient absorption spectroscopy in the study of processes and dynamics in biology, 246, 201 hole burning spectroscopy and physics of proteins, 246, 226 ultraviolet/visible spectroelectrochemistry of redox proteins, 246, 701 diode array detection in liquid chromatography, 246, 749. 

Probing Metalloproteins Electronic absorption spectroscopy of copper proteins, 226, 1 electronic absorption spectroscopy of nonheme iron proteins, 226, 33 cobalt as probe and label of proteins, 226, 52 biochemical and spectroscopic probes of mercury(ii) coordination environments in proteins, 226, 71 low-temperature optical spectroscopy metalloprotein structure and dynamics, 226, 97 nanosecond transient absorption spectroscopy, 226, 119 nanosecond time-resolved absorption and polarization dichroism spectroscopies, 226, 147 real-time spectroscopic techniques for probing conformational dynamics of heme proteins, 226, 177 variable-temperature magnetic circular dichroism, 226, 199 linear dichroism, 226, 232 infrared spectroscopy, 226, 259 Fourier transform infrared spectroscopy, 226, 289 infrared circular dichroism, 226, 306 Raman and resonance Raman spectroscopy, 226, 319 protein structure from ultraviolet resonance Raman spectroscopy, 226, 374 single-crystal micro-Raman spectroscopy, 226, 397 nanosecond time-resolved resonance Raman spectroscopy, 226, 409 techniques for obtaining resonance Raman spectra of metalloproteins, 226, 431 Raman optical activity, 226, 470 surface-enhanced resonance Raman scattering, 226, 482 luminescence... 

Figure 8. Top Transient dichroism signal of I2 in n-hexane. Bottom Linear prediction singular-value decomposition (LP-SVD) for the pump and probe wavelengths of 580 and 475 nm, respectively. Note the overall delay of the negative signal, which is modulated by the B state frequency. (From Ref. 28.)...

S. J. Johnson, P. L. Frattini and G. G. Fuller, Simultaneous dichroism and birefringence measurements of dilute colloidal suspensions in transient shear flow, J. Colloid Interface Sci., 104,440 (1985) S. J. Johnson and G. G. Fuller, Flowing colloidal suspensions in non-Newtonian suspending fluids decoupling the composite birefringence, Rheol. Acta, 25, 405 (1986). 

Magnetic quantum beats in the transient process after pulsed depopulation of the ground state may be observed not only in fluorescence, but also in a more direct way, namely in absorption. In connection with what was discussed in Section 3.5, one must expect maximum sensitivity if the experiment is conducted according to the laser interrogated dichroism method see Fig. 3.17. To this end it is convenient to direct the external magnetic field B along the 2-axis as shown in Fig. 4.21 where the probe beam E-vector can be either in the xy plane (Em) or in the yz plane (Epr2). 

Keywords Absolute configuration and conformation determinations Density functional theory Induced solvent chirality Transient VCD measurements Vibrational circular dichroism... 

The BPh (1) which is reduced transiently when the reaction center is excited with a short flash of light (or is reduced semipermanently if reaction centers are illuminated continuously at low temperature in the presence of Q and reduced cytochromes) is the one that absorbs at longer wavelengths, 545 and 760 nm in Rb. sphaeroides [52,70,71,75,76]. Measurements of the linear dichroism of oriented Rp. viridis crystals indicate that this is BPhL [129,136]. This assignment agrees with the identification of as menaquinone and Qg as ubiquinone in Rp. viridis [32], since menaquinone is on the same side of the reaction center as BPhL (F g- 4). 

A crystal structural analysis of the salt [Rh(bpy)3]Cl3-4H20 has been reported 401). The natural abundance NMR spectrum of [Rh(bpy)3l + has been recorded 84). Flash photolysis or pulse radiolysis of [Rh(bpy)3] + produces a transient formally rhodium(II) species, which is best formulated [Rh "(bpy)2(bpy )] 169, 652, 801). The ion has been resolved as its (-l--tris- L-cysteinesulfinato(2)S,iV cobalt-ate(III) salt 214) and circular dichroism (CD) spectra described 591, 592). The toxicity of [Rh(bpy)3 salts has been noted and interpreted in terms of specific interactions 264,297,953). The reduction of CO2 to formate in aqueous solution is catalyzed by [Rh(bpy)3] + 278). 

P. Jones, W. J. Jones, and G. Williams, Transient optical dichroism in photochromic polymer glass and its relationship to molecular reorientation, J. Chem. Soc., Faraday Trans. 86, 1013-1014 (1990). 

A review of rheo-optical techniques by Sherman et al. (1996) notes that there has been an increase in the use of rheo-optic set-ups both for FT-IR dichroism and for dynamic IR dichroism spectroscopies for polymer melts and polymer blends. Skytt et al. (1996) highlight the use of simultaneous measurement of the transient or steady-state rheological properties and IR dichroism to characterize orientation in polymer melts. However, there is little reference to dual spectroscopic-rheological techniques for reactive polymer systems in the literature. 

Hogan M, Dattagupta N, Crothers DM. Transient electric dichroism of rodlike DNA molecules. Proc Natl Acad Sci USA 1978 75 195-199. 

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