Biomedical subjects

G Canizal

Publications and source records attributed to G Canizal.

3 recordsLinked to original sources

PubMed2006

Structural selection and amorphization of small Ni-Ti bimetallic clusters.

Classical molecular dynamics simulation is used for structural thermodynamic analysis of Ni-Ti bimetallic clusters. Experimental observation for the nanoclusters synthesized by the bioreduction method is used to consolidate the conclusion. The results demonstrate that Ni-Ti nanoclusters as small as 2-3 nm are not energetically favorable for common ordered geometrical arrangements such as cuboctahedron, decahedron, and icosahedron, though they can be synthesized experimentally. For the elemental distribution, Ni and Ti tend to aggregate separately. In the cases under study, eutectic-like and Ni-core/Ti-shell structures can keep their basic shape and elemental distribution during long periods of relaxation at room temperature. For other cases such as solid solution and Ti-core/Ni-shell, the structures amorphized and the elements tend to distribute uniformly even though they are at temperatures as low as room temperature. Experimental evidence was obtained by the analysis of biosynthesized nanoparticles using transmission electron microscopy techniques. This allowed determination of the partial amorphized structures of small bimetallic particles with cubic and multiple twined-like structures.

Journal Article↗

PubMed2006

Neodymium nanoparticles: biosynthesis and structural analysis.

Small metallic nanoparticles of neodymium are obtained by a facile route based on the biosynthesis and the pH conditions that demonstrate the possibility of obtaining particles of 1-8 nm. The size is controlled by synthesis conditions. Smaller clusters were obtained with pH = 5, while for pH = 10 evidences of nanorods productions are found and this opens the perspective to use this rare-earth element for zero and one dimensional based applications. Using transmission electron microscopy techniques, the size distribution and structure are studied. Density functional theory-based calculations allow the determination of the lowest energy configuration, which is based on the hexagonal bulk symmetry. Theoretical models are used to simulate the high resolution transmission electron microscopy to identify the experimental image, determining that the synthesized nanoparticles reach the lowest energy hexagonal configurations.

Computer Simulation↗

PubMed2006

Synthesis and characterization of Mn quantum dots by bioreduction with water hyacinth.

The bio-reduction method is reported as a part of a complimentary self-sustained technology, where bioremediation and metal particle production are related. The use of the characterization methods in this self sustainable technique open the expectative to be used for several other elements and with other plants, which will be discussed. However, the particular case of Mn nanoparticles involves an important option to generate nanoparticles in the range of 1-4 nanometers with a well controlled size and with a structure based on an fcc-like geometry for the smallest clusters and with more complex arrays for cluster greater than four shells, which involves magnetic moments significantly related to their atomistic configuration. At the same time, the use of the characterization methods establishes the dependence of the nanoparticle's size on the pH conditions used during the synthesis; small clusters in the range of 1-2 nm were generated using pH=5, and it was shown that for the smallest aggregates, simple polyhedron shapes are stable.

Biomass↗