Periodic inclusion of room-temperature-ferromagnetic metal phosphide nanoparticles in carbon nanotubes

We demonstrate the use of sequential catalytic growth to encapsulate iron, nickel-iron, and iron-cobalt phosphide catalyst nanoparticles periodically along the entire lengths of carbon nanotubes. Investigations by local electron spectroscopies and electron diffraction reveal the compositions and crystal structures of the encapsulated particles. Significantly, high spatial resolution magnetic characterization using magnetic force microscopy and off-axis electron holography demonstrates that encapsulated iron-cobalt phosphide nanoparticles are ferromagnetic at room temperature, in accordance with the properties of bulk metal phosphides of the same structure and composition.     

Analysis of Acidic Drugs in Swiss Wastewaters

Five acidic drugs (clofibric acid, ibuprofen, ketoprofen, mefenamic acid and diclofenac) were chosen in order to determine their behavior in a sewage treatment plant (STP). An analytical method using solid phase extraction (SPE) and a gas chromatograph coupled with a mass spectrometer (GC-MS) was used. The results show that four pharmaceuticals (clofibric acid, ketoprofen, mefenamic acid and diclofenac) are not well removed by treatment in Swiss STPs. Maximum concentration in the effluent was determined for mefenamic acid up to 1.0 µg/L. This component seems to be relevant in Swiss STPs effluents and we can expect its presence in surface waters.     

Theoretical study of fast repair of DNA damage by cistanoside C and analogs: Mechanism and docking

Experiments show that the natural substances phenylpropanoid glycosides (PPGs) extracted from pelicularis spicata are capable of repairing DNA damaged by oxygen radicals. Based on kinetic measurements and experiments on tumor cells, a theoretical study of the interaction between PPG molecules and isolated DNA bases, as well as a DNA fragment has been performed. An interaction mechanism reported early has been refined. The docking calculations performed using junction minimization of nucleic acids (JUMNA) software showed that the PPG molecules can be docked into the minor groove of DNA and form complexes with the geometry suitable for an electron transfer between guanine radical and the ligand. Such complexes can be formed without major distortions of DNA structure and are further stabilized by the interaction with the rhamnosyl side-groups.     

From Substrate to Coating: Micro- and Surface Analysis Techniques for the Development of Steel Products

For the development of ultra high strength steel and hyperdrawable steel grades precipitates had to be tailored at the nanoscale. Microbeam techniques helped to reach a superior quality of metallic coatings and a superb adhesion to the steel substrate. In this paper the use of micro-analytical techniques in steel product development is illustrated.     

The novel YMn2D6 deuteride synthesized under high pressure of gaseous deuterium

The novel intermetallic deuteride YMn₂D₆ was synthesized under high deuterium pressure. In order to identify the structure and characterize the magnetic properties of this deuteride the powder X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Mn X-ray absorption near edge structure (XANES) and magnetization measurement (SQUID) were carried out. The crystal structure, the chemical state of Mn and the magnetic properties of this novel deuteride were examined and discussed. It should be noted that the structure of YMn₂D₆ (F-43m) differs dramatically from C15 symmetry of the parent material. Such a great rearrangement of the metal lattice due to deuterium absorption is rather exceptional for C15 Laves phase.     

Quantification of MgO surface excess on the SnO2 nanoparticles and relationship with nanostability and growth

In this work, we experimentally showed that the spontaneous segregation of MgO as surface excess in MgO doped SnO₂ nanoparticles plays an important role in the system's energetics and stability. Using X-ray fluorescence in specially treated samples, we quantitatively determined the fraction of MgO forming surface excess when doping SnO₂ with several different concentrations and established a relationship between this amount and the surface energy of the nanoparticles using the Gibbs approach. We concluded that the amount of Mg ions on the surface was directly related to the nanoparticles total free energy, in a sense that the dopant will always spontaneously distribute itself to minimize it if enough diffusion is provided. Because we were dealing with nanosized particles, the effect of MgO on the surface was particularly important and has a direct effect on the equilibrium particle size (nanoparticle stability), such that the lower the surface energy is, the smaller the particle sizes are, evidencing and quantifying the thermodynamic basis of using additives to control SnO₂ nanoparticles stability.     

Electrodeposition of Ag nanoparticles onto carbon coated TEM grids: A direct approach to study early stages of nucleation

An innovative experimental approach to study the electrodeposition of small nanoparticles and the early stages of electrochemical nucleation and growth is presented. Carbon coated gold TEM grids are used as substrates for the electrodeposition of silver nanoparticles so that electrochemical data, FESEM, HAADF–STEM and HRTEM data can be acquired from the same sample without the need to remove the particles from the substrate. It is shown that the real distribution of nanoparticles cannot be resolved by FESEM whereas HAADF–STEM analysis confirms that a distribution of ‘small’ nanoparticles (d ≈ 1–2 nm) coexist with ‘large’ nanoparticles corresponding to a bimodal size distribution. Besides, particles grown under the same conditions have been found to present different structures such as monocrystals, polycrystals or aggregates of smaller particles.     

New model for gas evolving electrodes based on supersaturation

A new model for gas evolving electrodes is proposed, in which the gas evolution reaction is driven by the supersaturation of dissolved gas.