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The adsorption of human serum albumin onto polystyrene (PS) and polymethylmethacrylate (PMMA) blend surface from five different pH solutions is studied using x-ray photoemission electron microscopy. Albumin exhibits completely extended (pH 2.0) and a completely contracted (pH 10.0) structures, but at the intermediate stages (pH 4.0) albumin opens some hydrophilic sites and shows preferential adsorption for hydrophilic PMMA.

The C 1s spectral features are interpreted with the aid of ab initio calculation for core excitation of benzene, biphenyl, hexafluorobenzene, and decafluorobiphenyl. A weak feature at 287.7 eV in biphenyl is identified as a C 1s -->pi(super *)(sub deloc) transition, characteristic of ring-ring delocalization and its intensity and position are shown to be related to the average torsion angle.

The first in situ measurements with scanning transmission X-ray microscopy (STXM) of an active electrochemical cell are reported. An electrochemical wet cell, consisting of an electrodeposited polyaniline thin film on a thin Au film covered by an overlayer of 1 M HCl solution sitting between two X-ray transparent silicon nitride windows, was assembled. X-ray absorption images and spatial and time-resolved spectra of this system under potential control were examined using the beamline 5.3.2 STXM at the Advanced Light Source. The chemical state of the polyaniline film was reversibly converted between reduced (leucoemeraldine) and oxidized (emeraldine chloride) states by changing the applied potential. The electrochemical changes were monitored by spatially resolved C 1s and N 1s X-ray absorption spectroscopy and chemical-state selective imaging. Comparison of differences between images at two energies at different potentials provided electrochemical contrast with a resolution better than 50 nm, thereby monitoring that component of the polyaniline film that was electrochemically active. Kinematic studies in the subsecond regime are demonstrated.

The C 1s, Si 2p, Si 2s and O 1s inner-shell excitation spectra of vinyltriethoxysilane, trimethylethoxysilane and vinyltricetoxysilane is recorded by electron energy loss spectroscopy under scattering conditions dominated by electric dipole transitions. The use of the measurements in assisting chemistry studies of adhesion promoters for electronic applications is discussed.

A study was conducted to analyze the sensitivity of near-edge X-ray absorption fine structure to differences in key chemical components of polyurethane polymers. The polymers were chosen to isolate particular chemical environments present in complex polyurethane polymers. Results indicated that differences in phenyl ring substitution promote significant variations in transition energies and character.

The 3D chemical structure (4D spectromicroscopy) of nanoporous Al2O3 aerogels coated with ZnO by atomic layer deposition (ALD) was studied by multienergy scanning transmission X-ray microscopy. These materials are representative of a class of designer catalysts in which the nanoporous support is prepared separately from the active catalyst material, which is subsequently introduced by ALD, thereby allowing independent optimization of the morphology, chemistry, and spatial distribution of the support and catalyst. The samples studied were prepared by Ga ion and Xe plasma focused ion beam (FIB) milling as well as drop casting from water suspension. Zn L and Al K edge spectra of six samples with three different ZnO loadings were measured to investigate how loading and different sample preparation methods affect the 3D distribution of the ZnO and Al2O3. Scanning transmission X-ray microscopy (STXM) and ptychographic imaging at two energies each at the Zn L3 and Al K edge were measured. The ptychography data were analyzed by using the SHARP reconstruction code to generate quantitative 2D chemical maps of the Al2O3 and the ZnO. The STXM and ptychography maps were then measured at a sequence of tilt angles, covering up to 160° of rotation. The 3D structure of the ZnO and Al2O3 was derived from the tilt series data by tomographic reconstruction using a compressed sensing algorithm. A two-dimensional spatial resolution (half-period) of 6 nm, measured by Fourier ring correlation, and a 3D spatial resolution (half-period) of 9 nm, measured by Fourier shell correlation, were achieved when using the COSMIC beamline at the Advanced Light Source (ALS). The results show that for all of the ZnO loadings studied there is nonuniform coverage of the ZnO on the Al2O3 aerogel framework. In addition, we found that both FIB methods create sample artifacts, although the distortion was less with Xe plasma than Ga ion FIB. [ABSTRACT FROM AUTHOR]

Summary: The most well‐recognized magnetoreception behaviour is that of the magnetotactic bacteria (MTB), which synthesize membrane‐bounded magnetic nanocrystals called magnetosomes via a biologically controlled process. The magnetic minerals identified in prokaryotic magnetosomes are magnetite (Fe3O4) and greigite (Fe3S4). Magnetosome crystals, regardless of composition, have consistent, species‐specific morphologies and single‐domain size range. Because of these features, magnetosome magnetite crystals possess specific properties in comparison to abiotic, chemically synthesized magnetite. Despite numerous discoveries regarding MTB phylogeny over the last decades, this diversity is still considered underestimated. Characterization of magnetotactic microorganisms is important as it might provide insights into the origin and establishment of magnetoreception in general, including eukaryotes. Here, we describe the magnetotactic behaviour and characterize the magnetosomes from a flagellated protist using culture‐independent methods. Results strongly suggest that, unlike previously described magnetotactic protists, this flagellate is capable of biomineralizing its own anisotropic magnetite magnetosomes, which are aligned in complex aggregations of multiple chains within the cell. This organism has a similar response to magnetic field inversions as MTB. Therefore, this eukaryotic species might represent an early origin of magnetoreception based on magnetite biomineralization. It should add to the definition of parameters and criteria to classify biogenic magnetite in the fossil record. [ABSTRACT FROM AUTHOR]