Ion-induced modifications

It is now well established that organic polymers are rather more sensitive to various ionizing radiations. In a recent study (23) it has been shown that the irradiation of polystyrene films by 20 MeV 28gi beam results in ion-induced modifications of the sample because a significant quantity of H and C nuclei is released when the beam dose is increased above 1012 ions cm 2. Similar effects of erosion of H and C profiles of plasma-polymerized hexamethydisilasene (HMDSN) thin... 

Kumar, S. Kumar, R. Singh, D.P. 2009. Swift heavy ion induced modifications in cobalt doped ZnO thin films Structural and optical studies. Applied Surface Science, 255( 18) 8014-8018. 

Singhal, R. Agarwal, D.C. Mishra, Y.K. Mohapatra, S. Avasthi, D.K. Chawla, A.K. Chandra, R. Pivin, J.C. 2009. Swift heavy ion induced modifications of optical and microstructural properties of silver-fullerene C o nanocomposite. Nuclear Instruments and Methods in Physics Research, Section B, 267(8-9) 1349-1352. 

Kanjilal D, Swift heavy ion-induced modification and track formation in materials. Current Science, 80, 12, 1560-1566, 2001. 

Punzon-Quijoma E, Torres-Costa V, Manso-Silvan M, Martin-Palma RJ, Climent-Font A (2012) MeV Si ion beam implantation as an effective patterning tool for the localized formation of porous silicon. Nucl Instrum Methods Phys Res 282 25-28 Ruano GD, Ferron J, Koropecki RR (2009a) Reversible ion induced modification of consequent secondary electron emission in porous silicon. Open Surf Sci J 1 46 Ruano GD, Ferron J, Koropecki RR (2009b) Secondary electron emission in nanostmctured porous silicon. J Phys Conf Ser 167 012006... 

One example of energetic ion-induced modification is the implantation of chemically active ions (see Figures 3.8 and 3.19). In specific cases, this can also result... 

In conclusion, we want underline that three categories can all be defined as ion-beam processing or ion-beam-induced modification of materials ... 

The cytotoxicity of LDL can also be inferred from the study by Blake et al. (1985). In this study of human cultured endothelial cells, stored sera from patients with necrotizing arteritis demonstrated an enhanced tendency to develop oxidized LDL, which correlated closely with endothelial cell cytotoxicity. This process appears to require the presence of both oxygen and transition metal ions such as iron in the presence of a reducing agent (Gebicki ef /., 1991). There is considerable evidence that transition metals are involved in cell-induced modifications of LDL including the inhibitory effects of EDTA and desfer-rioxamine (Hiramatsu et 1987). A role for Of in LDL modification by endothelial cells and fibroblasts comes from studies showing inhibition of LDL oxidation by SOD (Steinbrecher, 1988). 

However, all of these studies were performed using model components in vitro—none have examined formaldehyde-induced modifications in vivo. Further, while modification sites have been mapped by MS/MS, intact cross-linked peptide species have not been observed in such experiments.49 This possibly indicates that the covalent bonds of the formaldehyde cross-links are not as strong as those of the peptide backbone. The resulting fragment ion spectra are similar to that of the unmodified peptide with the exception of 12Da or 30Da additions at modifications sites. Thirty Dalton modifications correspond to the addition of formaldehyde while 12 Da modifications indicate water elimination. 

Potential functions used82 were an exp-6 function with two free repulsive parameters and a modified exp-6 with three repulsive parameters. The modification was introduced as a screened ion-induced dipole attraction, which softens the repulsion at small r. The fitted potentials are shown in Fig- 10. The dashed curves in Fig. 9 show the fits obtained with the simple exponential repulsion and the solid curves with the modified repulsion. 

Time-resolved emission spectroscopy is gaining importance in the study of various chemical aspects of luminescent lanthanide and actinide ions in solution. Here, the author describes the theoretical background of this analytical technique and discusses potential applications. Changes in the solution composition and/or in the metal-ion inner coordination sphere induce modifications of the spectroscopic properties of the luminescent species. Both time-resolved spectra and luminescence decays convey useful information. Several models, which are commonly used to extract physico-chemical information from the spectroscopic data, are presented and critically compared. Applications of time-resolved emission spectroscopy are numerous and range from the characterization of the... 

Polymer films change their properties during ion implantation [25-29]. Carbonization mentioned above is one of the ion beam induced modification techniques for polymer surfaces. 

Hasegawa I, Niisato N, Iwasaki Y, Marunaka Y (2006) Ambroxol-induced modification of ion transport in human airway Calu-3 epithelia. Biochem Biophys Res Commun 343(2) 475 82... 

B.Y. Tsaur Ion-Beam-Induced Modifications of Thin Film Structures and Formation of Metastable Phases. Ph.D. Thesis, Calif. Inst, of Tech. (1980)... 

Kuntz and Roach34 carried out a series of classical trajectory calculations on reactions of the type A+ + BC - AB+ + C. The key in this approach is the construction of a realistic potential function representing the reaction. Kuntz and Roach used a modification of a potential energy function previously reported by Polanyi and Kuntz.35 A LEPS function36 with spectroscopic parameters adapted to the isolectronic reaction C1(D2, D)DC1 is added to a potential which contains the long-range ion-induced dipole forces peculiar to the reaction Ar+(D2, D)ArD +... 

B.S. Kaith, and A.S. Singha, "Modification of natural polymers-VII Ceric ion induced grafting of methylacrylate onto Flax fibre" International Congress of Chemistry and Environment, 2001. 

Ion Beam-Induced Modification of ZnO-Based Dilute Magnetic Semiconductor... 

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