A5059506776- Ion-surface interactions and analysis
- Mass Spectrometry Techniques and Applications
- Analytical chemistry methods development
- Combustion and Detonation Processes
- Bacterial biofilms and quorum sensing
- Atmospheric chemistry and aerosols
- Antifungal resistance and susceptibility
- Energetic Materials and Combustion
- Spectroscopy and Chemometric Analyses
- Nanopore and Nanochannel Transport Studies
- Nanofabrication and Lithography Techniques
- Thermal and Kinetic Analysis
- Advanced Chemical Sensor Technologies
- Bacterial Identification and Susceptibility Testing
- Electron and X-Ray Spectroscopy Techniques
- Atmospheric and Environmental Gas Dynamics
- Force Microscopy Techniques and Applications
- Polymer Surface Interaction Studies
- Chemical Thermodynamics and Molecular Structure
- Nuclear Physics and Applications
- Metabolomics and Mass Spectrometry Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Diamond and Carbon-based Materials Research
- Photochromic and Fluorescence Chemistry
- Metallic Glasses and Amorphous Alloys
University of Münster
2016-2025
National Physical Laboratory
2014-2017
University of the West Indies
2008-2016
University of Washington
1989-2014
University of the West Indies System
2010-2011
University of Utah
2001-2008
Brigham Young University
2005-2008
Montana State University
1995-2002
University of Manchester
1967-1991
University of Cambridge
1962-1985
Abstract An algorithm for generating depth profiles from angle‐dependent XPS data has been developed. The uses the regularization method with non‐negativity constraints. Four criteria determining optimal amount of solution smoothing have investigated. A criterion that least‐squared error in regenerated set proved most effective selecting smoothing. Simulated a two‐layer sample were used to investigate effects number points, where each point consisted spectra acquired at take‐off angle. also...
The quantitative determination of the lattice disorder present in graphene layers will be crucial if this 2-D material is to commercialized. Raman spectroscopy has been shown a powerful technique for characterizing density these defects layers. Here, we study evolution spectra with defect size, vacancy created via ion bombardment. was used analyze variation D-peak and G-peak intensity ratio single-layer graphene, whilst equivalent highly ordered pyrolytic graphite were characterized using...
A novel photoresponsive and fully conjugated N-heterocyclic carbene (NHC) has been synthesized that combines the excellent photophysical properties of arylazopyrazoles (AAPs) with an NHC acts as a robust surface anchor (AAP-BIMe). The formation self-assembled monolayers (SAMs) on gold was proven by ToF-SIMS XPS, organic film displayed very high stability at elevated temperatures. This also reflected in desorption energy, which determined temperature-programmed SIMS measurements....
The resistance of Candida albicans biofilms to a broad spectrum antimicrobial agents has been well documented. Biofilms are known be heterogeneous, consisting microenvironments that may induce formation resistant subpopulations. In this study we characterized one such subpopulation. C. were cultured in tubular flow cell (TF) for 36 h. relatively large shear forces imposed by draining the TF removed most biofilm, which consisted tangled mass filamentous forms with associated clusters yeast...
Matrix-enhanced secondary ion mass spectrometry and matrix-assisted laser desorption/ionization are two imaging techniques used to image biological molecules in cells tissues. Both utilize an organic matrix coating enhance the detection of molecular ions. The homogeneity crystal size critical for obtaining high quality images. Sublimation/deposition is currently widely apply a layer onto sample because its ability produce homogeneous layers with small sizes. Additionally, absence solvent...
Multivariate analysis has become increasingly common in the of multidimensional spectral data. We previously showed that multivariate technique principal component (PCA) is an excellent method for interpreting static time-of-flight secondary ion mass spectrometry (TOF-SIMS) spectra adsorbed protein films. PCA unsupervised pattern recognition loses resolution between different proteins as more are added to data set due large within-group variation. The supervised techniques discriminant...
Abstract We have studied the surface chemistry of two lots Biomer™ (BSP067 and BSUAOOl), widely used commercial poly(ether urethane) (PEU). Although transmission infrared adsorption studies revealed no differences in bulk lots, chemistry, as seen by x‐ray photoelectron spectroscopy (XPS) static secondary ion mass spectrometry (SIMS), was different. Lot BSP067 showed softsegment enrichment at surface, which is typical PEU. BSUAOOl evidence either hard‐ or soft‐segment PEU components surface....
P. G. Ashmore and B. J. Tyler, Trans. Faraday Soc., 1962, 58, 1108 DOI: 10.1039/TF9625801108
Carbon dioxide is a stable constituent of the atmosphere that has no major terrestrial sinks other than atmospheric transport in absence photosynthetic activity by plants. In urban atmospheres, CO 2 mixing ratios are often elevated above ambient large local sources from combustion. We measured and isotopic composition at four locations Salt Lake Valley, Utah, during persistent cold pool event winter 2004. The results showed strong influence stability height capping inversion on suggested...
P. G. Ashmore, M. Burnett and B. J. Tyler, Trans. Faraday Soc., 1962, 58, 685 DOI: 10.1039/TF9625800685
Abstract High spatial resolution mass spectrometry imaging has been identified as a key technology needed to improve understanding of the chemical components that influence antibiotic resistance within biofilms, which are communities micro-organisms grow attached surface. Time-of-flight secondary ion (ToF–SIMS) offers unique ability for label-free 3D organic molecules with sub-micrometer and high sensitivity. Several studies biofilms have done help ToF–SIMS, but none those shown antibiotics...
Abstract Nanoparticles offer unique physical and chemical properties. Dip pen nanolithography of nanoparticles enables versatile patterning nanofabrication with potential application in electronics sensing, but is not well studied yet. Herein, the patterned deposition various onto unmodified silicon substrates presented. It shown that aqueous solutions hydrophilic citrate cyclodextrin functionalized gold as poly(acrylic) acid decorated magnetite are feasible for writing nanostructures. Both...
The adsorption of mussel adhesive protein (MAP) from the marine Mytilus edulis has been investigated on polystyrene (PS) and poly(octadecyl methacrylate) (POMA) surfaces using angle dependent X-ray photoelectron spectroscopy (XPS) atomic force microscopy (AFM). AFM images previously published in dehydrated state contact mode are compared with acquired hydrated fluid Tapping Mode to assess contribution that hydration architecture adsorbed proteins. To further characterize layer, XPS analysis...
Interpretation of time-of-flight secondary ion mass spectroscopy (TOF-SIMS) images from rough samples such as particles, fibers, or biological specimens can be problematic because the are influenced not only by sample chemistry but also topographical features. In this article we have investigated influence spherical and cylindrical features on total yields, relative feature shape. TOF-SIMS Pluronic coated fibers polystyrene spheres were collected using both triple focusing time reflectron...
ABSTRACT An in situ method for sensitive detection of differences the action chlorhexidine against subpopulations cells Candida albicans biofilms is described. Detection relies on monitoring kinetics propidium iodide (PI) penetration into cytoplasm individual during dosing with chlorhexidine. Accurate estimation time delivery concentration to substratum was facilitated by using a flow cell system which transport interfacial region previously characterized. A model developed quantify rates PI...