UPON-MODIFICATION

RAMSES is usually generated from molecular structures in a VB representation. The details of the connection table (localized charges, lone pairs, and bond orders) are kept within the model and are accessible for further processes. Bond orders are stored with the n-systems, while the number of free electrons is stored with the atoms. Upon modification oF a molecule (e.g., in systems dealing with reactions), the VB representation has to be generated in an adapted Form from the RAMSES notation. 

The change in the electronic properties of Ru particles upon modification with Se was investigated recently by electrochemical nuclear magnetic resonance (EC-NMR) and XPS [28]. In this work, it was established for the first time that Se, which is a p-type semiconductor in elemental form, becomes metallic when interacting with Ru, due to charge transfer from Ru to Se. On the basis of this and previous results, the authors emphasized that the combination of two or more elements to induce electronic alterations on a major catalytic component, as exemplified by Se addition on Ru, is quite a promising method to design stable and potent fuel cell electrocatalysts. 

Goethals, P. and Stevens, M. (1994). Dimensional stability and decay resistance of wood upon modification with some new type chemical reactants. International Research Group on Wood Preservation, Doc. No. IRG/WP 94 0028. 

Before discussing novel in situ ETEM developments for heterogeneous catalysis, we present some background information about various in situ developments in the materials sciences. A number of notable in situ experiments have relied upon modifications to the standard TEM operations. The main electron optical functions of the TEM, especially the electron gun, depend on a high vacuum environment. The typical 10 -10 mbar TEM environment is mildly reducing. With an ECELL, controlled chemically reducing atmospheres, such as... 

Sorption capacity is one of the major properties used for industrial applications of zeolites. H. Lee reviews the aspects of zeolites used as adsorbents. The other papers in the section deal with the theory of sorption and diffusion in porous systems, the variation of sorption behavior upon modification, and the variation of crystal parameters upon adsorption. NMR and ESR studies of sorption complexes are reported. H. Resing reviews the mobility of adsorbed species in zeolites studied by NMR. 

The effect of protic additives was rationalized by the formation of hydrogen-bonded adducts, such as that between benzoic acid and the carbonyl group of the coordinated benzoate, as observed by 1H NMR. Such an adduct would be expected to facilitate the formation of a polar transition state. The reaction rate also increases upon modification of the ligand with anionic groups and in polar solvents. Radical initiators have no effect. 

In this section, experimental data on the spectroscopic changes observed upon modifications of the medium surrounding the luminescent probe will be first presented. These changes do not include inner-sphere complexation of the probe itself, a topic examined in detail in sect. 5. However, the term luminescent probe may refer to a complex, for which the lifetime changes induced by modifications of the surrounding medium are investigated. The various models and empirical approaches that have been used to interpret the data will then be presented and discussed. 

Deuteration is the exchange of surface silanol hydrogen atoms for deuterium. This process has been used to study the surface and structural properties of silica and their variation upon modification. The isotopic exchange of H for D is highly favoured by the kinetic isotope effect, because the mass of the D atom is double that of the H atom. 

The reaction with C02, as reported for the dried aminosilane polymer also occurs with immobilized aminosilane molecules. Culler43 reported that approximately half of the amine groups are reacting with C02 when silica samples modified with APTS in aqueous solution, are dried in air. Comparison with AEAPTS and a triaminosilane showed that only primary amines react with C02. The reaction product is evidenced by FTIR bands at 1630, 1575, 1488 and 1332 cm 1. Also after modification in dry conditions and drying at room temperature in humid air, the reaction with C02 may be observed. Characteristic infrared bands appear upon modification at high concentrations of APTS. Figure 9.32 shows the infrared spectrum of dry silica, modified with a 10% APTS/toluene solution, after air drying for 30 minutes. 

Transmission electron microscopy and X-ray powder diffraction of 4.0% H2[PtCl6]/TH revealed the presence of about 200 nm large aggregates consisting of 2-4 nm sized anatase crystallites (12). Specific surface areas of unmodified P25 (50 m2/g) and Aid (3 m2/g) were not changed upon modification whereas the area of TH decreased from 334 m2/g to 260 m2/g. 

The spectral shifts of the iron complexes of transferrins occurring upon modification of amino groups were particularly prominent with succinylated derivatives. Absorption spectra in the visible range for succinylated chicken ovotransferrin are seen in Fig. 17. The changes were a shift in the maximum from 465 mp to shorter wavelengths, and an increase in absorption at approximately 400 mp. Similar but slightly different spectral shifts have been obtained by treatment of metal free transferrins with hydrogen peroxide (82) (Komatsu and Feeney, 1966 un-... 

Mogharrab N, Ghourchian H, Amininasab M (2007) Structural stabilization and functional improvement of horseradish peroxidase upon modification of accessible lysines experiments and simulation. Biophys J 92 1192-1203... 

In this paper we have described a design approach for heterogeneous enantioselective catalysts. The approach is based upon modification of the counter-cation of zeolites or mesoporous alumino-silicates with a suitable chiral ligand.7 We have demonstrated the approach with two examples (a) enantioselective aziridination of alkenes using Cu2+-exchanged zeolite Y modified with chiral oxazolines and (b) the modification of... 

There is increasing use of NMR in the study of protein conformation (Gronenborn and Clore, 1990). Its application to the study of conformational changes upon modification of a-lactalbumin is considered in Section IX,E. 

The involvement of lysine amino acid residues on cytochrome c in the heterogeneous reactions with functionalized electrodes seems to have been established. Importantly, it is now thought that the proposed protein-promoter complex is more likely to be dynamic, as revealed by the results of a recent investigation (28) of site-specific 4-chloro-3,5-dinitrophenyl (CDNP)-substituted cytochrome c. It was found that monosubstitution of either Lys 13 or Lys 72 did not result in any significant change in its electrochemical response, whereas two modifications greatly decreased the heterogeneous rate constant, and complete loss of electrochemical activity was observed upon modification of more lysines. It was proposed that the electrode reaction occurred in numerous rotational conformations. Therefore, for the mono-... 

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