Pulse irradiated aqueous solutions

Maughan RL, Michael BD, Anderson RF. (1978) The application of wide band transformers to the study of transient conductivity in pulse irradiated aqueous solutions by the d.c. method. Radiat Phys Chem 11 229-238. 

Concerning other Group V elements, some low temperature (77 K) ESR radiation studies have verified the existence of 2c/lc radical cations with P.. P and As. . As bonds. 149,150 in solution, only one mention has been made, namely, on (Et3P. .PEt3)" .15i. in this case assignment was made on the basis of a transient optical absorption at 385 nm obtained upon reaction of OH radicals with triethyl phosphine in pulse irradiated aqueous solution at pH >7. The high pH was necessary to prevent the phosphorus from protonation and keep the phosphorus lone pair available for both, one-electron oxidation and P-P orbital coupling. 

The discovery of the hydrated electron in irradiated aqueous solutions has made it necessary to re-examine the mechanisms proposed for the irradiation of aqueous solutions of substances which are biologically important. The new technique of pulse radiolysis has provided a breakthrough in many ways, particularly in determining absolute rate constants. These advances have made it possible to begin working out the reactivity of solvated electrons in vivo, although it is not yet possible to specify the precise role of the reactions in radiation biology. 

Dorfman, C.M., Taumb, I.A., and Buhler, R.E., Pulse radiolysis studies. I. Transient spectra and reaction rate constant in irradiated aqueous solution of benzene, /. Chem. Phys., 36, 3051-3061, 1962. 

Nese C, Schuchmann MN, Steenken S, von Sonntag C (1995) Oxidation vs fragmentation in radiosensitization. Reactions of a-alkoxyalkyl radicals with 4-nitrobenzonitrile and oxygen. A pulse radiolysis and product study. J Chem Soc Perkin Trans 2 1037-1044 Neta P (1972) Electron spin resonance study of radicals produced in irradiated aqueous solutions of 5-halouracils. J Phys Chem 76 2399-2402... 

A large variety of organic radicals have been produced in irradiated aqueous solutions and monitored by their optical absorption spectra. Pulse radiolysis techniques allow the recording of such spectra and... 

In the course of pulse radiolysis studies of purine and pyrimidine bases, Fielden et al. (1970) and Greenstock et al. (1973b) have been able to follow the kinetics of deprotonation of these compounds by OH- produced in the irradiated aqueous solution. The observation is made possible by the difference in ultraviolet absorption between the neutral and basic forms. The rate constants for deprotonation were found to be (1-2) x 101 0 M s-1 and those for the protonation of the anion by H+, 4 x 1010 M I s-1. 

With the discovery of the hydrated electron and the newly available technique of pulse radiolysis rapid advances were made in the understanding of the processes which occur in irradiated aqueous solutions. For an excellent review of the current state of knowledge see reference 36. The chemistry of the hydrated electron has been reviewed in detail by Hart and Anbar(37), but its reactions can be summarised as ... 

The hydrated electron represents a ubiquitous entity in irradiated aqueous solutions, and its experimental discovery by pulse radiolysis has raised considerable interest in investigations of electron-transfer reactions in chemistry and radiobiology (i, 47-49). The dynamical component of an excess electron in a polar solution is directly dependent on transient electron-solvent couplings. The excess electron is equivalent to a microprobe that can test the inhomogeneous structures of a reaction area. This elementary charge exhibits several delo-cahzed or localized states in the condensed phase 14, 16, 18, 29). 

By pulse radiolysis of nitrous oxide-saturated aqueous solutions of ferricyanide (2 X 10 " M) and various alcohols (0.1 M), Adams and Willson " were able to obtain absolute rate coefficients for the ferricyanide oxidation of the radicals derived from the alcohols by attack of the solvent irradiation product, OH-. 

Soft-pulse multiple irradiation In this method, pre-saturation is done using shaped pulses having a broader excitation profile. Therefore, it is a more suitable method for the suppression of multiplets. This technique is very effective, easy to apply and easy to implement within most NMR experiments. In aqueous solutions, however, slowly exchanging protons would be detectable due to the occurrence of transfer of saturation. In addition, the spins with resonances close to the solvent frequency will also be saturated. 

Henglein [71] has used pulsed ultrasound and has shown that the degree of polymerisation decreases when the duration of pulsed ultrasound is decreased. The growth and collapse of cavitation bubbles require a finite time - they are not instantaneous. Henglein has also shown that the rate (and degree of polymerisation) depends upon the nature of the gas used to saturate the system. For the polymerisation ofmethacrylic acid in aqueous solution, a 15 min irradiation yielded 10.7% conversion in the presence of Nj, 1.8% conversion in the presence of O2 (low presumably due to inhibition) and no polymerisation in a degassed solution). 

Dajka, K Takacs, E Solpan, D Wojnarovits, L Guven, O. High-energy irradiation treatment of aqueous solutions of C.l. Reactive Black 5 azo dye pulse radiolysis experiments. Radiation Physics and Chemistry, 2003 67, 535-538. 

Polymer radicals can be observed in irradiated solid polymer (ESR) and in aqueous solutions (pulse radiolysis), in concentrations comparable with the eventual crosslinking density. 

Fig. 1. Computer trace of the time-dependence of the formation of [( )5 - 2 02 ]+ followed at 300 nm and first order plot (insert). (1M CH3C02Na, 1 x 10 3 M C0SO4, 20% NH3, N20 saturated aqueous solution irradiated with a maximum pulse.)...

The problems associated with the M11 state of the elements of group III have been noted previously cf. Sections 25.1.13 and 25.2,3). The Tl2+ ion has been identified in pulse radiolysis decomposition of aqueous TI2SO4,350,351 and in y-irradiated frozen aqueous solutions.352... 

ARS2 (1-10 pmole) was mixed with a 100-fold molar excess of sinap-inic acid in an aqueous solution containing 10% trifluoroacetic acid (TFA). The mixture was placed inside a JMS-LDI 1700 time-of-flight (TOF) MS spectrometer (JEOL, Japan) and irradiated with a nitrogen laser (337 nm, 3 ns pulse). The ions formed by each pulse were accelerated by a 30 kV potential into a 1.7 m evacuated tube. 

Effect of separation space on yield was found in some experiments. A higher quantum yield was observed for In2S3 with larger particle size when the electron transfer to methylviologen in aqueous solution was examined by pulse-laser irradiation.13) A decrease in the yield of the products with decreasing size has also been reported for the photocatalytic polymerization of methyl methacrylate with ZnO of the size ranging from 4 to 40 nm 15) this was attributed to the increase in the recombination caused by the reduction of the dimensions. 

Adams GE, Armstrong RC, Charlesby A, Michael BD, Willson RL (1969) Pulse radiolysis of sulphur compounds, part 3. Repair by hydrogen transfer of a macromolecule irradiated in aqueous solution. Trans Faraday Soc 65 732-742... 

Box HC, Budzinski EE, DawidzikJB, Wallace JC, lijima H (1998) Tandem lesions and other products in X-irradiated DNA oligomers. Radiat Res 149 433-439 Budzinski EE, DawidzikJB, Rajecki MJ, Wallace JC, Schroder EA, Box HC (1997) Isolation and characterization of the products of anoxic irradiation of d(CpGpTpA). Int J Radiat Biol 71 327-336 Candeias LP, O Neill P, Jones GDD, Steenken S (1992) Ionization of polynucleotides and DNA in aqueous solution by 193 nm pulsed laser light identification of base-derived radicals. Int J Radiat Biol 61 15-20... 

Ward JF (1988) DNA damage produced by ionizing radiation in mammalian cells identities, mechanisms of formation, and repairability. Progr Nucleic Acid Res Mol Biol 35 95-125 Ward JF, Kuo I (1976) Strand breaks, base release and postirradiation changes in DNA y-irradiated in dilute 02-saturated aqueous solution. Radiat Res 66 485-498 Ward JF, Mora-Arellano VO (1984) Pulse radiolysis studies of WR-1065. Int J Radiat One Biol Phys 10 1533-1536... 

Wardman P, Dennis MF, Everett SA, Patel KB, Stratford MRL, Tracy M (2003) Radicals from one-electron reduction of nitro compounds, aromatic N-oxides and quinones the kinetic basis for hypoxia-selective, bioreductive drugs. Biochem Soc Symp 61 171-194 Warman JM, de Haas MP, Hummel A, van Lith D, VerberneJB, Loman H (1980) A pulse radiolysis conductivity study of frozen aqueous solutions of DNA. Int J Radiat Biol 38 459-459 Warman JM, de Haas MP, Rupprecht A (1996) DNA a molecular wire Chem Phys Lett 249 319-322 Warters RL, Lyons BW (1992) Variation in radiation-induced formation of DNA double-strand breaks as a function of chromatin structure. Radiat Res 130 309-318 Warters RL, Hofer KG, Harris CR, Smith JM (1977) Radionuclide toxicity in cultured mammalian cells Elucidation of the primary site of radiation damage. Curr Top Radiat Res Q 12 389-407 Weiland B, Huttermann J (1998) Free radicals from X-irradiated, dry and hydrated lyophilized DNA as studies by electron spin resonance spectroscopy analysis of spectral components between 77 K and room temperature. Int J Radiat Biol 74 341-358 Weinfeld M, Soderlind K-JM (1991) 32P-Postlabeling detection of radiation-induced DNA-damage identification and estimation of thymine glycols and phosphoglycolate termini. Biochemistry 30 1091-1097... 

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