Two-dimensional roughening of adsorbate islands in thermodynamic equilibrium

Equilibrium fluctuations of islands of adsorbed O atoms on Ru(0001) were investigated by scanning tunneling microscopy (STM), density functional theory calculations (DFT) and Monte Carlo (MC) simulations. Very ramified (2 x 2)-O islands were observed by high-speed STM that point to complex interactions between the O atoms. The DFT calculations show that, in addition to pairwise attractive interactions between third-nearest neighbors, a repulsive three-body interaction exists between these. MC simulations that include three-body interactions reproduce the observed ordering behavior.     

Biocorrosion studies of TiO<Subscript>2</Subscript> nanoparticle-coated Ti–6Al–4V implant in simulated biofluids

The corrosion behaviors of the TiO₂ nanoparticles coated bioimplant Ti–6Al–4V exposed to three different simulated biofluids (SBF), namely, (1) NaCl solution, (2) Hank’s solution, and (3) Cigada solution, were studied by using micro-Raman spectroscopy, electrochemical techniques, and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). The different electrochemical impedance spectroscopy models were applied to fit the data obtained from the implants before and after the coating of TiO₂ nanoparticles (50–100 nm). It was found that the TiO₂ nanoparticle coatings increased the thickness of the pre-existing oxide layer on the Ti–6Al–4V surface, serving to improve the bioimplant corrosion resistance.     

Academic librarians at play in the field of cheminformatics: building the case for chemistry research data management

There are compelling needs from a variety of camps for more chemistry data to be available. While there are funder and government mandates for depositing research data in the United States and Europe, this does not mean it will be done well or expediently. Chemists themselves do not appear overly engaged at this stage and chemistry librarians who work directly with chemists and their local information environments are interested in helping with this challenge. Our unique understanding of organizing data and information enables us to contribute to building necessary infrastructure and establishing standards and best practices across the full research data cycle. As not many support structures focused on chemistry currently exist, we are initiating explorations through a few case studies and focused pilot projects presented here, with an aim of identifying opportunities for increased collaboration among chemists, chemistry librarians, cheminformaticians and other chemistry professionals.     

Carbonation and Other Super Saturated Gases as Solution Modifiers for Improved Sensitivity in Solvent Assisted Ionization Inlet (SAII) and ESI

Solvent Assisted Ionization Inlet (SAII) produces ions in a heated inlet to a mass spectrometer from aqueous and aqueous/organic solutions with high sensitivity. However, the use of acid modifiers, which typically aids electrospray ionization, generally results in ion suppression in SAII. Here we demonstrate that the use of carbonation and other super-saturated gases as solution modifiers increases analyte ion abundance and reduces metal cation adduction in SAII. Carbonation is also found to enhance electrospray ionization. The mechanistic and practical utility of carbonation in mass spectrometry is addressed.      

Determination of the antiferroquadrupolar order parameters in UPd(3)

By combining accurate heat capacity and x-ray resonant scattering results we have resolved the long standing question regarding the nature of the quadrupolar ordered phases in UPd(3). The order parameter of the highest temperature quadrupolar phase has been uniquely determined to be antiphase Q{zx} in contrast to the previous conjecture of Q{x{2}-y{2}}. The azimuthal dependence of the x-ray scattering intensity from the quadrupolar superlattice reflections indicates that the lower temperature phases are described by a superposition of order parameters. The heat capacity features associated with each of the phase transitions characterize their order, which imposes restrictions on the matrix elements of the quadrupolar operators.     

X-ray resonant scattering study of the quadrupolar order in UPd3

Quadrupolar ordering in a 5f electron system has been observed directly for the first time, using x-ray scattering techniques. In UPd (3) at low temperatures satellite peaks appear at (1,0,l) (orthorhombic notation) with l odd and even. Both sets of peaks show a resonant enhancement of the scattering at the M(IV) edge of U. At resonance, the dominant scattering of the l odd peaks occurs in the unrotated polarization channel, whereas for l even a significant rotated component is found. These results are discussed in terms of possible structures of the antiferroquadrupolar phases.     

Field desorption mass spectrometry of air sensitive transition metal complexes

Field desorption mass spectrometry was used to obtain molecular weight information on a variety of transition metal complexes which are air sensitive and nonvolatile. The base peak for the neutral complexes is the molecular ion and for the salt complexes is the cation.     

Community engagement and informed consent in the International HapMap project

The International HapMap Consortium has developed the HapMap, a resource that describes the common patterns of human genetic variation (haplotypes). Processes of community/public consultation and individual informed consent were implemented in each locality where samples were collected to understand and attempt to address both individual and group concerns. Perceptions about the research varied, but we detected no critical opposition to the research. Incorporating community input and responding to concerns raised was challenging. However, the experience suggests that approaching genetic variation research in a spirit of openness can help investigators better appreciate the views of the communities whose samples they seek to study and help communities become more engaged in the science.