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We study the use of polymer gratings as light couplers into porous silicon planar waveguides for sensing applications. Experimental evidence of a guided mode in a grating-coupled porous silicon structure is presented, along with a study of its detuning due to waveguide infiltration with a chemical linker. All the measurements are in good agreement with simulations obtained by means of a Fourier modal method, where the porous silicon birefringence is considered. These results demonstrate that this system is potentially useful for chemical and biological sensing applications. [ABSTRACT FROM AUTHOR]

Carbon nanofibers are high-aspect ratio graphitic materials that have been investigated for numerous applications due to their unique physical properties such as high strength, low density, metallic conductivity, tunable morphology, chemical and environmental stabilities, as well as compatibility with organochemical modification. Surface studies are extremely important for nanomaterials because not only is the surface structurally and chemically quite different from the bulk, but its properties tend to dominate at the nanoscale due to the drastically increased surface-to-volume ratio. This review surveys recent developments in surface analysis techniques used to characterize the surface structure and chemistry of carbon nanofibers and related carbon materials. These techniques include scanning probe microscopy, infrared and electron spectroscopies, electron microscopy, ion spectrometry, temperature-programed desorption, and atom probe analysis. In addition, this article evaluates the methods used to modify the surface of carbon nanofibers in order to enhance their functionality to perform across an exceedingly diverse application space. [ABSTRACT FROM AUTHOR]

In this study, different accelerating voltages were applied in the ion-milling process to fabricate CoPt nanopillar arrays in order to investigate the influence of ion damage to magnetic properties. Nanopillar arrays fabricated at a higher accelerating voltage give a lower value of coercivity and ion damage does not broaden the switching field distribution (SFD). The ‘edge damage’ model was employed in micromagnetic simulations to investigate the reversal mechanism and SFD. The results shows that the edge damage can change the switching mode from coherent rotation to nucleation followed by rapid domain wall motion, and the broad SFD mainly comes from the intrinsic anisotropy distribution, rather than size distribution. In addition, the angle dependence of the switching field measurement shows that nanopillars with damaged edges have Stoner–Wohlfarth behaviour, which indicates that fitting the Stoner–Wohlfarth curve does not necessarily mean coherent rotation. It is the comparison between the field for domain wall motion and the nucleation field that determines the location of angle dependence curves. [ABSTRACT FROM AUTHOR]

The antiferromagnetic domain structure in LaFeO3 thin-film epilayers grown on Lao7Sr0,3MnO3 is imaged combining linearly polarized x-ray-absorption spectroscopy with photoemission electron microscopy. Detailed analysis of polarization-dependent domain contrast from magnetic dichroism reveals two sets of symmetrically different antiferromagnetic easy axes in the LaFeO3 layer along the in-plane (110) and (100) crystalline axes (pseudocubic notation), respectively. We show that extended antiferromagnetic domains can be stabilized selectively for nanowires defined in this perovskite thin-film system along either orientation of the easy axes. The results demonstrate how the equilibrium domain structure of thin-film nanoscale antiferromagnets depend on a combination of substrate symmetry, nanowire dimensions, and in-plane crystalline orientation. [ABSTRACT FROM AUTHOR]

Atomic force microscopy (AFM) provides a unique opportunity to study live individual bacteria at the nanometer scale. In addition to providing accurate morphological information, AFM can be exploited to investigate membrane protein localization and molecular interactions on the surface of living cells. A prerequisite for these studies is the development of robust procedures for sample preparation. While such procedures are established for intact bacteria, they are only beginning to emerge for bacterial spheroplasts. Spheroplasts are useful research models for studying mechanosensitive ion channels, membrane transport, lipopolysaccharide translocation, solute uptake, and the effects of antimicrobial agents on membranes. Furthermore, given the similarities between spheroplasts and cell wall-deficient (CWD) forms of pathogenic bacteria, spheroplast research could be relevant in biomedical research. In this paper, a new technique for immobilizing spheroplasts on mica pretreated with aminopropyltriethoxysilane (APTES) and glutaraldehyde is described. Using this mounting technique, the indentation and cell elasticity of glutaraldehyde-fixed and untreated spheroplasts of E. coli in liquid were measured. These values are compared to those of intact E. coli. Untreated spheroplasts were found to be much softer than the intact cells and the silicon nitride cantilevers used in this study.