A New Method for the Measurement of Low Concentrations of OH/O2-Radical Species in Water by High-LET Pulse Radiolysis. A Time-Resolved Chemiluminescence Study

2000 ◽  
Vol 104 (38) ◽  
pp. 8709-8714 ◽  
Author(s):  
V. Wasselin-Trupin ◽  
G. Baldacchino ◽  
S. Bouffard ◽  
E. Balanzat ◽  
M. Gardès-Albert ◽  
...  
2001 ◽  
Vol 79 (2) ◽  
pp. 171-175
Author(s):  
V Wasselin-Trupin ◽  
G Baldacchino ◽  
B Hickel

A new method for the detection of low concentrations of hydroxyl and superoxide radicals, formed by water radiolysis, is described in this article. The method used is the time resolved chemiluminescence. It has been performed with an electron beam delivered by a Febetron 707 accelerator. This method allows to measure hydroxyl and superoxide radical concentrations in a large range of concentrations, between 10–5 and 10–8 M.Key words: chemiluminescence, pulse radiolysis, hydroxyl radical, superoxyde radical.[Traduit par la Rédaction]


2001 ◽  
Vol 79 (2) ◽  
pp. 180-183 ◽  
Author(s):  
G Baldacchino ◽  
V Trupin-Wasselin ◽  
S Bouffard ◽  
E Balanzat ◽  
M Gardès-Albert ◽  
...  

The radiolysis of water with heavy ions of high linear energy transfer (LET) (-dE/dx) is characterized, in deaerated medium, by the production of superoxide anions, the radiolytic yields of which increase with the LET. Radiobiological interest in such radical species comes from the oxidative stress which may be generated by their dismutation in O2 and H2O2 in anoxic medium (radiotherapy with heavy ions). A brief review of the measurements of superoxide free radicals in aqueous solution by indirect or direct methods is presented. Moreover, some experimental results obtained by pulse radiolysis with Ar18+ ions (TEL = 290 keV·µm-1), are described. The interpretation of the kinetics takes into account the superoxide absorbance and that of hydrogen peroxide, which is present at the millisecond time scale.Key words: pulse radiolysis, heavy ions, superoxide radicals, high LET, kinetics.[Traduit par la Rédaction]


Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.


2019 ◽  
Vol 210 ◽  
pp. 171-176
Author(s):  
Thorsten Wittemeier ◽  
Timothy G. Foat ◽  
Steven Herring ◽  
John S. Shrimpton ◽  
Zheng-Tong Xie

1975 ◽  
Vol 35 (4) ◽  
pp. 566-568 ◽  
Author(s):  
A.D. Trifunac ◽  
K.W. Johnson ◽  
B.E. Clifft ◽  
R.H. Lowers

1978 ◽  
Vol 75 (3) ◽  
pp. 519 ◽  
Author(s):  
Myran C. Sauer ◽  
Klaus H. Schmidt ◽  
Charles D. Jonah ◽  
Conrad A. Naleway ◽  
Edwin J. Hart

2015 ◽  
Vol 19 (1) ◽  
pp. 75-78
Author(s):  
Deba Bahadur Khadka

The cross sections for the deexcitation of Ne(3P1) by H2 have been measured as a function of the mean collisional energy in the range of 17.3-37.9 meV or in the temperature range from 134 K to 293 K using a pulse radiolysis method as combined with time-resolved optical absorption spectroscopy. The deexcitation cross sections are in the range of 2.1- 5.6 Å2 for Ne(3P1) and nearly constant or increase slightly with increasing the collisional energy.Journal of Institute of Science and Technology, 2014, 19(1): 75-78


Cytokine ◽  
2000 ◽  
Vol 12 (11) ◽  
pp. 1702-1711 ◽  
Author(s):  
Mary E Neville ◽  
Kurt W Richau ◽  
Lawrence T Boni ◽  
Laura E Pflug ◽  
Richard J Robb ◽  
...  
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