Transient poly

Simbulan-Rosenthal CM, Rosenthal DS, Iyer S et al. Transient poly(ADP-ribosyl)ation of nuclear proteins and role of poly(ADP-ribose) polymerase in the early stt s of apoptosis. J Biol Chem 1998 273(22) 13703-13712. 

Ghoreishy, M. H. R. and Nassehi, V., 1997. Modelling the transient flow of rubber compounds in the dispersive section of an internal mixer with slip-stick boundary conditions. Adv. Poly. Tech. 16, 45-68. 

Excitation of an aqueous solution of poly(A/St/Phen) with a 355-nm, 22-ps laser pulse in the presence of MV2+ generated a transient absorption band peaking at about 600 nm due to MV + [120]. As shown in Fig. 16, the buildup of the 600-nm band completes immediately after the pulse excitation, indicating that the photoinduced ET from the singlet-excited Phen residue ( Phen ) to MV2 + occurs on a time scale comparable to or shorter than the duration of the laser pulse (ca. 22 ps) [120], Figure 16 also shows that a fast decay of the absorbance at 600 nm owing to the back ET from MV + to the Phen cation radical (Phen+ )... 

Fig. 16. Time-resolved transient absorption spectra for poly(A/St/Phen) (29) in aqueous solution in the presence of 5 mM MV2 + [Phen] (residue) = 0.66 mM. Delay times after the laser pulse are indicated [102]...

For APh-2, on the other hand, the forward ET from Phen to MV2+ was a little slower than that for the poly(A/St/Phen)-MV2+ system i.e., the intensity of the S <- Sj band for the Phen moiety at 510 nm still remained significant for 27 ps after the pulse excitation (Fig. 17) [120]. In striking contrast to the poly(A/St/Phen)-MV2 + system, the APh-2-MV2+ system showed an extremely fast decay in the transient absorbance at 600 nm over the picosecond regime and no subsequent slower decay. The transient absorbance almost completely decayed in 200 ps after the pulse. 

Fig. 18. Time profiles of transient absorbance at 602 nm due to MV+ for the poly (A/St/Phen)-MV2+ system [Phen](residue) = 0.66 mM [MV2+] = 5mM ( ), 10mM (a). The solid lines represent the best-fit curves calculated from Eq. 10 with the use of the parameters given in Table 6 [120]...

Equation (40) relates the lifetime of potential-dependent PMC transients to stationary PMC signals and thus interfacial rate constants [compare (18)]. In order to verify such a correlation and see whether the interfacial recombination rates can be controlled in the accumulation region via the applied electrode potentials, experiments with silicon/polymer junctions were performed.38 The selected polymer, poly(epichlorhydrine-co-ethylenoxide-co-allyl-glycylether, or technically (Hydrine-T), to which lithium perchlorate or potassium iodide were added as salt, should not chemically interact with silicon, but can provide a solid electrolyte contact able to polarize the silicon/electrode interface. 

Figure 36. Microwave conductivity transients of an n-type silicon/polymer (poly(epichlorhydrine-co-ethylenoxide-co-allyl-glycylether plus iodide) junction at 0 and -5V.

Figure 2.62 The l/t transient obtained during the growth of a poly thiophene film on a 6.30 cm2 Pt electrode at 1.80V vs. SCE in acetonitrile/0,1 M tetraethylammonium tetrafluoroborate electrolyte. At f = 7 s, the potential was switched to OV to terminate the growth process. After...

Other groups may cause shortening of the lifetime. The phosphorescence of parvalbumin is quenched by free tryptophan with a quenching rate constant of about 10s M i s l (D. Calhoun, unpublished results). A more extensive survey of proteins or model compounds with known distances between tryptophans is needed to study how adjacent tryptophans affect the lifetime. It should be noted that at low temperature the phosphorescence lifetime of poly-L-tryptophan is about the same as that of die monomer.(12) This does not necessarily mean that in a fluid solution tryptophan-tryptophan interaction could not take place. Thermal fluctuations in the polypeptide chain may transiently produce overlap in the n orbitals between neighboring tryptophans, thus resulting in quenching. 

Dynamic Light Scattering and Transient Electric Birefringence Study of Poly(vinyI chloride) Micrc els... 

Mozer AJ, 8ariciftci N8, Pivrikas A, Osterbacka R, Juska G, Brassat L, Bassler H (2005) Charge carrier mobility in regioregular poly(3-hexylthiophene) probed by transient conductivity techniques a comparative study. Phys Rev B 71 035214... 

A Summary of Published Data for Transient Maximal Plasma Concentrations of Diet-Derived (Poly)Phenols, Typical Plasma Concentrations of Endogenous Phenols and ... 

Fig. 2. a) Transient decays from poly(A) (triangles) and poly(dA) (circles) at 570 run in back-to-back experiments at neutral pH. The solid curves are fits. The inset provides a short time view along with the signal from AMP (crosses), b) Normalized transient absorption at 570 nm following UV excitation of poly(A) at the indicated temperatures. 

Fig. 3. Transient absorption signals from a) poly(A) (normalized) and b) AMP at 570 nm in back-to-back experiments at different pHs. The solid curves are fits.

Further evidence that the long-time components are associated with excitations in base-stacked regions comes from pH-dependent measurements. The transient decays of poly(A) and AMP solutions are shown in Fig. 3 at several pH values. The pK values of poly(A) and AMP are 5.87 and 3.8, respectively [14]. As seen in the figure, the relative fraction of the... 

Fig. 4. Transient absorption signals of poly(C) at 570 nm at pH 7 (o) and pH 5 ( ). The pH 5 transient has been offset vertically for clarity. Solid lines are best-fit curves.

Transient absorption experiments were performed on the cytosine homopolymer poly(C) as a function of pH. Poly(C) adopts a double-stranded form in the pH range between 3.8 and 5.5 [21], which was previously reported to be more fluorescent than the cytosine monomer [22]. In the double-stranded form, two poly(C) strands are joined in parallel fashion by hemiprotonated base pairs, in which paired cytosine residues share a single proton. At higher pH values, poly(C) is present solely in single-stranded form. 

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