Recent Patents on Nanotechnology - Volume 8, Issue 1, 2014

Many patents have been devoted to developing medical nanometer zirconia ceramic grinding techniques that can significantly improve both workpiece surface integrity and grinding quality. Among these patents is a process for preparing ceramic dental implants with a surface for improving osseo-integration by sand abrasive finishing under a jet pressure of 1.5 bar to 8.0 bar and with a grain size of 30 µm to 250 µm. Compared with other materials, nano-zirconia ceramics exhibit unmatched biomedical performance and excellent mechanical properties as medical bone tissue and dentures. The removal mechanism of nano-zirconia materials includes brittle fracture and plastic removal. Brittle fracture involves crack formation, extension, peeling, and chipping to completely remove debris. Plastic removal is similar to chip formation in metal grinding, including rubbing, ploughing, and the formation of grinding debris. The materials are removed in shearing and chipping. During brittle fracture, the grinding-led transverse and radial extension of cracks further generate local peeling of blocks of the material. In material peeling and removal, the mechanical strength and surface quality of the workpiece are also greatly reduced because of crack extension. When grinding occurs in the plastic region, plastic removal is performed, and surface grinding does not generate grinding fissures and surface fracture, producing clinically satisfactory grinding quality. With certain grinding conditions, medical nanometer zirconia ceramics can be removed through plastic flow in ductile regime. In this study, we analyzed the critical conditions for the transfer of brittle and plastic removal in nano-zirconia ceramic grinding as well as the high-quality surface grinding of medical nanometer zirconia ceramics by ELID grinding.

Because of the high surface energy, nanoparticles show strong tendency to agglomeration or aggregation during preparations and applications, which thus greatly deteriorate their performance. Investigations have proven that redispersible nanoparticles can exhibit enhanced performances or be used in new technical applications as compared with the non-redispersible nanoparticles. The redispersity or solubility of particles is defined as their ability for re-forming colloidlike suspension after they are redispersed in solvent. The redispersity/solubility of particles can be obtained by establishing compatibility between particles and solvent through various techniques. In this review, we will give summary descriptions about related methods and their mechanism for the fabrication of redispersible or soluble particles. Also, outlook for the development and applications in this area will be given.

Since the discovery of catalysis, the identification of the different species in the mechanism involved in the reaction has been a challenge. When nanocatalysis entered the scene, the detection of material that came out from solutions attracted the attention and raised several questions: was this solid part of the nanocatalyst? was it the precursor of the nanocatalysts (the so-called precatalyst)? or was it the nanocatalyst itself? The discussion focuses on whether the catalysis is determined by the species that exist in solution or if it is generated from the support and hence the catalytic reaction is carried out with these soluble species. Furthermore, it appears that leaching is a phenomenon which occurs mainly in palladium- catalyzed reactions and that involves palladium nanoparticles (NPs). The research, findings and patents in the leaching process in catalytic reactions are reviewed in the present paper.

In this review, we have presented the controlled synthesis of Fe-based metal and oxide nanoparticles with large size by chemical methods. The issues of the size, shape and morphology of Fe nanoparticles are discussed in the certain ranges of practical applications in biology and medicine. The homogeneous nanosystems of Fe-based metal and oxide nanoparticles with various sizes and shapes from the nano-to-micro ranges can be used in order to meet the demands of the treatments of dangerous tumors and cancers through magnetic hyperthermia and magnetic resonance imaging (MRI). In this context, the polyhedral Fe-based metal and oxide nanoparticles having large size in the ranges from 1000 nm to 5000 nm can be potentially used in magnetic hyperthermia and MRI in the innovative drug delivery, diagnosis, treatment, and therapy of tumor and cancer diseases because of their very high bio-adaptability. We have suggested that high stability and durability of Fe-based metal and oxide nanoparticles are very crucial to recent magnetic hyperthermia and MRI technology. The roles of various Fe-based nanostructures are focused in biomedical applications of tumors and cancers diagnostics, targeted drug delivery, and magnetic hyperthermia. Finally, Fe-based, α-, β- and γ-Fe2O3, and Fe3O4-based nanoparticles are shortly discussed in various potential applications in catalysis, biology, and medicine.

The basic and the higher fullerenes were chromatographically isolated from the obtained series of carbon soot extracts, in increased yields, by the new, advanced methods, on Al2O3 columns. The elution was performed continuously, in one phase of each process, at ambient conditions, with the several different original hexane-toluene gradients. Various separation systems were used previously. The unique and the main, dominant absorption maxima of the purified higher fullerenes were registered in the spectral regions where they intensively absorb, applying the IR and UV/VIS techniques. All the observed absorption bands are in excellent agreement with theoretical calculations, indicating the achieved advancement in chromatographic separation and spectroscopic characterization. The isolated fullerenes are important for investigation of their remarkable optical and electronic properties, as well as for the numerous possible applications in chemistry, physics, biomedicine, diagnostic and therapeutic agents, sensors, polymers, nanophotonic materials, special lenses, optical limiting, organic field effect transistors, solar cells etc.