Volume 3, Issue 5 - Special issue: Nanotechnology: from convergence to divergence / Issue editor: Jae-Seung Lee

High-resolution electron microscopy and electron diffraction are quite useful for structural characterization of perovskite-type superconducting copper oxides on the atomic scale. Valuable information on the crystal structures and the microstructures could be obtained from observed high-resolution images if severe conditions such as thinner crystals and definite defocus values are satisfied. The structure images and electron diffraction patterns include information not only on accurate atomic coordinates of cations but also on ordered arrangements of oxygen atoms and oxygen vacancies. Crystal structures of the various perovskite-type copper oxides were analyzed from the observed structure images. Modulated structures, defects, intergowth, surfaces, and interfaces were also investigated.

The aim of the present work is a spectroscopic and thermodynamic study of DNA catalytic properties in the following processes: a) redox; b) formation of interstrand crosslinks; c) performing of photodynamic effects; d) nanoscale resonance radiationless electron excitation energy transfer. The most attention is paid to the latter, as it is truly nanoscale method in its origin. The nanoscale method of laser-induced fluorescence resonance energy transfer (FRET) to donor (acridine orange)-acceptor (ethidium bromide) intercalator pair for quantitative and qualitative study of stability quality DNA double helix in solution in real time is used. The FRET method allows to estimate the concentration of double helix areas with high quality stability applicable for intercalation in DNA after it is subjected to stress effect. It gives the opportunity to compare various types of DNAs with 1) different origins; 2) various degrees of damage; 3) being in various functional states. An alternative model and mechanisms of photodynamic effect on DNA in solutions are proposed. They are based on photoenergy degradation in solutions. The energy activates electrolytic dissociation of water molecules on H 3 O + and OH - and acts as a catalyst for hydrolysis reactions of phosphordiester and glycoside linkages.

In this review, the author’s results are observed in the field of the computerized modeling of the multicomponent mass transport kinetic processes in the bifunctional matrixes of the various shapes: spherical r -bead, cylindrical ro -fiber, planar L -membrane for the updated sorbent materials – nanocomposites (NC). The new contemporary NC model is developed for investigations of the multicomponent mass transfer kinetics in the bifunctional matrix of NC materials. The key concept of the author’s model is based on the two routes approach ( I and II ) for the multicomponent mass transfer inside the bifunctional NC matrix. These two routes function simultaneously and together: route I – for the mass transformation in reactions of dissociation ( I a ) and association ( I b ) onto the active nanocenters-nanosites ( R 0 ) expressed in the “sinks” and “sources” terms, and simultaneously there is carried out along the second II route the multicomponent diffusion of the i components (D i ) in the pores of the bifunctional ( I + II ) NC matrix with the forming of the diffusion i concentration waves. Transformations of the masses of the diffusing i components that occur on I -route are described by the equilibria relations of mass action laws and may be determined as “selectivity” of the nanosites – R 0 in the NC matrix. All factors of the author’s NC model are included into the description of the NC kinetics by multicomponent mass transfer partial differential equations. The propagating concentration waves represent the results of the computerized solution of the mass transfer equations. The equations for the all i components participating in the NC mass transport processes are completed by the additional J k fluxes that are described by the “sinks” and “sources” mechanism for the mass transformation on the I route. One of the main result of the computer modeling with the formulated NC model positions: it has been shown that the basic properties of the multicomponent mass transfer in the rather simple NC system are analogous to the characteristics of the dynamic process of chromatography. This similarity concludes in the fact that the multicomponent selectivity ( I ) and diffusion ( II , D i ) influence on the propagating concentration i waves are in analogy to the sorption isotherms and HETP parameters of the theory of multicomponent chromatography. The corresponding estimations in the NC kinetics are presented by using the integral parameters: C enter of M ass ( CM R ), and Dispersion ( Disp R ) for the k R 0 concentration waves of the formed R 0 nanosite distribution. There is a demonstrated analogy between the propagation of the kinetic k R 0 concentration wave and dynamic wave behavior in the chromatographic column. The essential feature concludes in the propagation of the formed k R 0 wave inside the NC matrix, though its diffusivity is zero (D R =0, as the R 0 nanosites are fixed). The new displacement effect is displayed in the result of the computer simulation for the two i concentration diffusion waves invading and interfering into the ion exchange (IEX) matrix (including the 3 d concentration wave coming out from the IEX matrix) for the ternary nonselective IEX kinetics where selectivity factor ( I ) is absent.

Silver nanomaterials have attracted a lot of interest from researchers, mainly owing to their distinctive optical properties such as localized surface plasmon resonance (LSPR) and surface-enhanced Raman scattering (SERS). These properties are particularly interesting for the diagnostic applications when combined with target-recognition capabilities of surface ligands and target concentration-dependent quantitative aspects of the LSPR or SERS signal. This review covers these two main optical properties of silver nanomaterials with respect to their sensing applications for various chemical and biological targets. The LSPR-based colorimetric detection schemes are further divided into two categories based on what they depend on: (1) assembly and (2) deformation of the silver nanoparticle probes. Because the various shapes of the silver nanomaterials are highly associated with how to design and control the LSPR- and SERS-based detection schemes, the latest progress in the development of highly sensitive and selective detection strategies are discussed with respect to the morphological diversity of the silver nanomaterials.

In this paper, the results of the adsorption and catalytic properties of the mono- and bimetallic palladium and rhodium nanoparticles (0.7–6.5 nm) impregnated on γ-Al 2 O 3 were presented. Metal nanoparticles were obtained in reverse micelles by two reduction methods: radiation-chemical and chemical reduction of ions. Three types of bimetallic nanoparticles Rh core /Pd shell , Pd core /Rh shell and substitution alloy Rh-Pd were obtained. The isotope exchange H 2 +D 2 ⇄2HD and the conversion ortho -H 2 ⇄ para -H 2 reactions were used as model catalytic processes. It was found that with increasing ω =[H 2 O]/[surfactant] in addition to increasing the size of the formed particles, also the ratio of particle sizes in a micellar system changes, and in systems with a high value ω , the formation of fine particles is observed. The BMNPs of Rh core /Pd shell type, showing a synergistic effect in the catalytic properties of reactions involving molecular hydrogen, were obtained [K s (Rh core /Pd shell )>4 K s (Rh or Pd)]. The dependence of the catalytic activity for Rh and Pd NPs on their sizes was obtained. The catalytic activity of the NPs increases with their diameters in the studied range of sizes. The phenomenon of aggregation (sintering) of Rh NPs at a temperature of 800°C was observed. Reflected attempt to compare the optical absorption spectra with the type of nanoparticles.