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328 records returned

Is precession electron diffraction kinematical? Part II A practical method to determine the optimum precession angle.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A series of experiments was undertaken to investigate the kinematical nature of precession electron diffraction data and to gauge the optimum precession angle for a particular system. Kinematically forbidden reflections in silicon were used to show how a large precession angle is needed to minimise multi-beam conditions for specific reflections and so reduce the contribution from dynamical diffraction. Small precession angles were shown to be detrimental to the kinematical nature of some low-order reflections. By varying precession angles, precession electron diffraction data for erbium pyrogermanate were used to inves...
Source: Ultramicroscopy - October 28, 2009 Category: Laboratory Medicine Authors: Eggeman AS, White TA, Midgley PA Tags: Ultramicroscopy Source Type: journals

Long-range correlations in In(2)O(3)(ZnO)(7) investigated by DFT calculations and electron holography.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The system In(2)O(3)(ZnO)(7) exhibits a strained ZnO-like domain structure intersected by indium containing, parallely arranged defect planes with a regular spacing of about 2.4nm. We propose that the strain within the domains originates from long-range electric fields due to charge localization at the defects inducing ionic displacements. The origin of the electric fields has been investigated theoretically by means of density functional theory (DFT). Calculated electric fields were incorporated as scattering potentials in holographic imaging simulations. Since the exact structure of the system is unknown, a novel str...
Source: Ultramicroscopy - October 25, 2009 Category: Laboratory Medicine Authors: Röder F, Lubk A, Lichte H, Bredow T, Yu W, Mader W Tags: Ultramicroscopy Source Type: journals

Multivariate statistics applications in phase analysis of STEM-EDS spectrum images.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Spectrum imaging (SI) methods are displacing traditional spot analyses as the predominant paradigm for spectroscopic analysis with electron beam instrumentation. The multivariate nature of SI provides clear advantages for qualitative analysis of multiphase specimens relative to traditional gray-scale images acquired with non-spectroscopic signals, where different phases with similar average atomic number may exhibit the same intensity. However, with the improvement in qualitative analysis with the SI paradigm has come a decline in the quantitative analysis of the phases thus identified, since the spectra from individua...
Source: Ultramicroscopy - October 24, 2009 Category: Laboratory Medicine Authors: Parish CM, Brewer LN Tags: Ultramicroscopy Source Type: journals

Theoretical aspects of image formation in the aberration-corrected electron microscope.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The theoretical aspects of image formation in the transmission electron microscope (TEM) are outlined and revisited in detail by taking into account the elastic and inelastic scattering. In particular, the connection between the exit wave and the scattering amplitude is formulated for non-isoplanatic conditions. Different imaging modes are investigated by utilizing the scattering amplitude and employing the generalized optical theorem. A novel obstruction-free anamorphotic phase shifter is proposed which enables one to shift the phase of the scattered wave by an arbitrary amount over a large range of spatial frequencie...
Source: Ultramicroscopy - October 21, 2009 Category: Laboratory Medicine Authors: Rose H Tags: Ultramicroscopy Source Type: journals

On the benefit of the negative-spherical-aberration imaging technique for quantitative HRTEM.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Employing an aberration corrector in a high-resolution transmission electron microscope, the spherical aberration C(S) can be tuned to negative values, resulting in a novel imaging technique, which is called the negative C(S) imaging (NCSI) technique. The image contrast obtained with the NCSI technique is compared quantitatively with the image contrast formed with the traditional positive C(S) imaging (PCSI) technique. For the case of thin objects negative C(S) images are superior to positive C(S) images concerning the magnitude of the obtained contrast, which is due to constructive rather than destructive superpositio...
Source: Ultramicroscopy - October 21, 2009 Category: Laboratory Medicine Authors: Jia CL, Houben L, Thust A, Barthel J Tags: Ultramicroscopy Source Type: journals

The quantitative measurement of magnetic moments from phase images of nanoparticles and nanostructures-I. Fundamentals.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An approach that can be used to measure the magnetic moment of a magnetized nanoparticle or nanostructure from an electron-optical phase image is introduced. The measurement scheme is based on integration of the gradient of the measured phase image within a circular boundary that contains the structure of interest. The quantity obtained is found to be directly proportional to the magnetic moment of the particle, with a constant of proportionality that does not depend on the particle's shape or magnetization state. The measurement of magnetic moments from both simulated and experimental phase images is demonstrated, and...
Source: Ultramicroscopy - October 17, 2009 Category: Laboratory Medicine Authors: Beleggia M, Kasama T, Dunin-Borkowski RE Tags: Ultramicroscopy Source Type: journals

SimulaTEM: Multislice simulations for general objects.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this work we present the program SimulaTEM for the simulation of high resolution micrographs and diffraction patterns. This is a program based on the multislice approach that does not assume a periodic object. It can calculate images from finite objects, from amorphous samples, from crystals, quasicrystals, grain boundaries, nanoparticles or arbitrary objects provided the coordinates of all the atoms can be supplied. PMID: 19853997 [PubMed - as supplied by publisher] (Source: Ultramicroscopy)
Source: Ultramicroscopy - September 30, 2009 Category: Laboratory Medicine Authors: Gómez-Rodríguez A, Beltrán-Del-Río LM, Herrera-Becerra R Tags: Ultramicroscopy Source Type: journals

Fabrication of ball-shaped atomic force microscope tips by ion-beam-induced deposition of platinum on multiwall carbon nanotubes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report that nano-scale ball tips can be fabricated by ion-beam-induced deposition (IBID) of Pt at the free end of multiwall carbon nanotubes that are attached to AFM tips. Scanning electron microscopy and transmission electron microscopy analyses were done on the Pt ball tips produced by IBID in this manner, using ranges of Ga ion beam conditions. The Pt ball tips produced consisted of aggregated Pt nano-particles and were found to be strong enough for AFM imaging. PMID: 19853998 [PubMed - as supplied by publisher] (Source: Ultramicroscopy)
Source: Ultramicroscopy - September 30, 2009 Category: Laboratory Medicine Authors: Ho Kahng Y, Choi J, Jeong K, Chon Park B, Kim DH, Lyou J, Lee JJ, Lee H, Lee T, Jung Ahn S Tags: Ultramicroscopy Source Type: journals

Interpretation of O K-edge EELS in zircon using a structural variation approach.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This work describes an approach to interpret the near-edge fine structure of electron energy-loss spectroscopy (EELS) of O K-edge in zircon using a structural variation method. The positions and intensities of several peaks in the O K-edge EELS spectrum are assigned to specific structural parameters. It suggests that the near-edge structures in EELS can be used to measure atomic structure changes. PMID: 19840891 [PubMed - as supplied by publisher] (Source: Ultramicroscopy)
Source: Ultramicroscopy - September 29, 2009 Category: Laboratory Medicine Authors: Jiang N, Spence JC Tags: Ultramicroscopy Source Type: journals

Application of image processing to STEM tomography of low-contrast materials.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, the effect of various image-processing techniques on the visibility of tomographic reconstructions is investigated for a low-contrast material system of non-uniform thickness containing complex features such as grain boundaries and nanoparticles. Starting with a tilt series of high-angle annular dark-field (HAADF) images from an area of Dy-doped YBa(2)Cu(3)O(7-x)-coated superconductor obtained using a scanning transmission electron microscope, various image-processing techniques were applied. These can be classified as edge detection, contrast-enhancing methods for non-uniform thickness and image sharpening....
Source: Ultramicroscopy - September 24, 2009 Category: Laboratory Medicine Authors: Ortalan V, Herrera M, Morgan DG, Browning ND Tags: Ultramicroscopy Source Type: journals

Probing the local temperature by in situ electron microscopy on a heated Si(3)N(4) membrane.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present a method allowing us to obtain localized heating that is compatible with high-temperature operation and real time scanning and transmission electron microscopy. Localized heating is induced by flowing current through tungsten nanowires deposited by focused ion-beam-induced deposition on a 50-nm-thick Si(3)N(4) membrane. Based on the heat transport between the nanowire and the substrate, we applied an analytical model to obtain the temperature profile as a function of electrical power. In this model, the key parameter is the thermal resistance between the nanowire and the substrate that we determined experimental...
Source: Ultramicroscopy - September 21, 2009 Category: Laboratory Medicine Authors: Reguer A, Bedu F, Nitsche S, Chaudanson D, Detailleur B, Dallaporta H Tags: Ultramicroscopy Source Type: journals

A model based reconstruction technique for depth sectioning with scanning transmission electron microscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Depth sectioning in high angular annular dark field scanning transmission electron microscopy is considered a candidate for three-dimensional characterization on the atomic scale. However at present the depth resolution is still far from the atomic level, due to strong limitations in the opening angle of the beam. In this paper we introduce a new, parameter based tomographic reconstruction algorithm that allows to make maximal use of the prior knowledge about the constituent atom types and the microscope settings, so as to retrieve the atomic positions and push the resolution to the atomic level in all three dimensions...
Source: Ultramicroscopy - September 19, 2009 Category: Laboratory Medicine Authors: Van den Broek W, Van Aert S, Van Dyck D Tags: Ultramicroscopy Source Type: journals

ELNES study of chemical solution deposited SrO(SrTiO(3))(n) Ruddlesden-Popper films: Experiment and simulation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article analyzes electron energy-loss near-edge fine structures of the SrO(SrTiO(3))(n=1) Ruddlesden-Popper system and of the parent compounds SrTiO(3) and SrO by comparison with first principles calculations. For that, the fine structures of chemical solution deposited Ruddlesden-Popper films have been experimentally recorded by means of transmission electron microscopy. Moreover, density of states computations using an all-electron density-functional code have been performed. It is shown that the appearance and shape of the experimental O-K and Ti-L(2,3) fine structure features result from the crystallography-depend...
Source: Ultramicroscopy - September 16, 2009 Category: Laboratory Medicine Authors: Riedl T, Gemming T, Weissbach T, Seifert G, Gutmann E, Zschornak M, Meyer DC, Gemming S Tags: Ultramicroscopy Source Type: journals

Effect of chromatic aberration on atomic-resolved spherical aberration corrected STEM images.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The effect of the chromatic aberration (C(c)) coefficient in a spherical aberration (C(s))- corrected electromagnetic lens on high-resolution high-angle annular dark field (HAADF) scanning transmission electron microscope (STEM) images is explored in detail. A new method for precise determination of the C(c) coefficient is demonstrated, requiring measurement of an atomic-resolution one-frame through-focal HAADF STEM image. This method is robust with respect to instrumental drift, sample thickness, all lens parameters except C(c), and experimental noise. It is also demonstrated that semi-quantitative structural analysis...
Source: Ultramicroscopy - September 16, 2009 Category: Laboratory Medicine Authors: Kuramochi K, Yamazaki T, Kotaka Y, Ohtsuka M, Hashimoto I, Watanabe K Tags: Ultramicroscopy Source Type: journals

Preservation of high resolution protein structure by cryo-electron microscopy of vitreous sections.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study large single crystals of lysozyme were vitrified and from these X-ray diffraction patterns extending to better than 2.1A were obtained. The crystals were high pressure frozen in 30% dextran, and cryo-sectioned using a diamond knife. In the best case, preservation to a resolution of 7.9A was shown by electron diffraction, the first observation of sub-nanometre structural preservation in a vitreous section. PMID: 19819624 [PubMed - as supplied by publisher] (Source: Ultramicroscopy)
Source: Ultramicroscopy - September 16, 2009 Category: Laboratory Medicine Authors: Sader K, Studer D, Zuber B, Gnaegi H, Trinick J Tags: Ultramicroscopy Source Type: journals

Medipix 2 detector applied to low energy electron microscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Low energy electron microscopy (LEEM) and photo-emission electron microscopy (PEEM) traditionally use microchannel plates (MCPs), a phosphor screen and a CCD-camera to record images and diffraction patterns. In recent years, however, MCPs have become a limiting factor for these types of microscopy. Here, we report on a successful test series using a solid state hybrid pixel detector, Medipix 2, in LEEM and PEEM. Medipix 2 is a background-free detector with an infinite dynamic range, making it very promising for both real-space imaging and spectroscopy. We demonstrate a significant enhancement of both image contrast and...
Source: Ultramicroscopy - September 16, 2009 Category: Laboratory Medicine Authors: van Gastel R, Sikharulidze I, Schramm S, Abrahams JP, Poelsema B, Tromp RM, van der Molen SJ Tags: Ultramicroscopy Source Type: journals

Validation and generalization of a method for precise size measurements of metal nanoclusters on supports.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We recently described a data analysis method for precise ( approximately 0.1A random error in the mean for a 200kV instrument with a 3A FWHM probe size) size measurements of small clusters of heavy metal atoms on supports as imaged in a scanning transmission electron microscope, including an experimental demonstration using clusters that were primarily triosmium or decaosmium. The method is intended for low signal-to-noise ratio images of radiation-sensitive samples. We now present a detailed analysis, including a generalization to address issues of particle anisotropy and biased orientation distributions. In the futur...
Source: Ultramicroscopy - September 16, 2009 Category: Laboratory Medicine Authors: Reed BW, Morgan DG, Okamoto NL, Kulkarni A, Gates BC, Browning ND Tags: Ultramicroscopy Source Type: journals

Technical note: A tool for determining rotational tilt axis with or without fiducial markers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Virtually all reliable TEM tomographic reconstructions in life science depend upon cross-correlating successive images in a tilt-stack, and then using gold nanobeads as fiducial markers for determining the relative image rotation axis. Although the rotational tilt angle is one of the essential parameters affecting the quality of tomographic reconstructions, little is discussed about its determination. We provide here a simple tool based on the property of Fast Fourier Transformation for determining this rotation axis offset angle. Our method uses two publicly-available software packages (IMOD and ImageJ), and can be us...
Source: Ultramicroscopy - September 10, 2009 Category: Laboratory Medicine Authors: Kobayashi A, Fujigaya T, Itoh M, Taguchi T, Takano H Tags: Ultramicroscopy Source Type: journals

Lorentz microscopy mapping for domain wall structure study in L1(0) FePd thin films.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Thin film alloys with perpendicular anisotropy were studied using Lorentz transmission electron microscopy (LTEM). This work focuses on the configuration of domain walls and demonstrates the suitability and accuracy of LTEM for the magnetic characterization of perpendicular magnetic anisotropy materials. Thin films of chemically ordered (L1(0)) FePd alloys were investigated by micro-magnetic modeling and LTEM phase retrieval approach. The different components of magnetization described by the modeling were studied on experimental images and confirmed by LTEM contrast simulation. Furthermore, quantitative measurements o...
Source: Ultramicroscopy - September 3, 2009 Category: Laboratory Medicine Authors: Masseboeuf A, Gatel C, Bayle-Guillemaud P, Marty A, Toussaint JC Tags: Ultramicroscopy Source Type: journals

A model based atomic resolution tomographic algorithm.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tomography with high angular annular dark field scanning transmission electron microscopy at atomic resolution can be greatly improved if one is able to take advantage of prior knowledge. In this paper we present a reconstruction technique that explicitly takes into account the microscope parameters and the atomic nature of the projected object. This results in a more accurate estimate of the atomic positions and in a good resistance to noise. The reconstruction is a maximum likelihood estimator of the object. Moreover, the limits to the precision have been explored, allowing for a prediction of the amount of expected ...
Source: Ultramicroscopy - August 26, 2009 Category: Laboratory Medicine Authors: Van den Broek W, Van Aert S, Van Dyck D Tags: Ultramicroscopy Source Type: journals

Spectroscopic imaging of electron energy loss spectra using ab initio data and function field visualization.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have devised a technique for spectral imaging using accurate ab initio electron energy loss near edge structure (ELNES) data and function field visualization. The technique is initially applied to a planar defect model in Si with different ring structures and no broken bonds where experimental probes are severely limited. The same model with B doping is also considered. It is shown that specific deviations in different energy ranges of the ELNES spectra are correlated with different structural components of the models. PMID: 19747777 [PubMed - as supplied by publisher] (Source: Ultramicroscopy)
Source: Ultramicroscopy - August 26, 2009 Category: Laboratory Medicine Authors: Rulis P, Lupini AR, Pennycook SJ, Ching WY Tags: Ultramicroscopy Source Type: journals

Distortion corrections of ESI data cubes for magnetic studies.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Measuring magnetic properties at a nanometre scale could be achieved in a transmission electron microscope by using dedicated techniques. Among these, the energy-loss magnetic chiral dichroism has already proven its efficiency and needs improvements to be widely used. The energy spectrum imaging technique can be used to measure dichroism but some image treatments are necessary due to distortions. This paper deals with the corrections that need to be applied on the data to remove all distortions, especially drift and non-isochromaticity, and extract reliable information. The measure and correction procedures are develop...
Source: Ultramicroscopy - August 26, 2009 Category: Laboratory Medicine Authors: Gatel C, Warot-Fonrose B, Schattschneider P Tags: Ultramicroscopy Source Type: journals

Indentation modulus and hardness of viscoelastic thin films by atomic force microscopy: A case study.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We propose a nanoindentation technique based on atomic force microscopy (AFM) that allows one to deduce both indentation modulus and hardness of viscoelastic materials from the force versus penetration depth dependence, obtained by recording the AFM cantilever deflection as a function of the sample vertical displacement when the tip is pressed against (loading phase) and then removed from (unloading phase) the surface of the sample. Reliable quantitative measurements of both indentation modulus and hardness of the investigated sample are obtained by calibrating the technique through a set of different polymeric samples...
Source: Ultramicroscopy - July 24, 2009 Category: Laboratory Medicine Authors: Passeri D, Bettucci A, Biagioni A, Rossi M, Alippi A, Tamburri E, Lucci M, Davoli I, Berezina S Tags: Ultramicroscopy Source Type: journals

StripeSTEM, a technique for the isochronous acquisition of high angle annular dark-field images and monolayer resolved electron energy loss spectra.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A technique capable of producing monolayer resolved electron energy loss (EEL) spectroscopy data along one direction in crystal structures is introduced. Unambiguous assignment of EEL spectra to atomic planes is possible via the execution of high angle annular dark-field (HAADF) imaging and EEL spectrum acquisition in parallel. The recording of instrumental instabilities in the HAADF image during the measurement enables a proper quantification by virtue of post-acquisition correction. Compared to the conventional line profile technique a dose reduction by several orders of magnitude can be achieved. The technique is ap...
Source: Ultramicroscopy - July 24, 2009 Category: Laboratory Medicine Authors: Heidelmann M, Barthel J, Houben L Tags: Ultramicroscopy Source Type: journals

Identification and ultrastructural imaging of photodynamic therapy-induced microfilaments by atomic force microscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we demonstrate identification and ultrastructural imaging of microfilaments using new approaches based on AFM. Photodynamic therapy (PDT) with a new chlorin-based photosensitizer DH-II-24 induced cell shrinkage, membrane blebbing, and reorganization of cytoskeletons in bladder cancer J82 cells. We investigated cytoskeletal changes using confocal microscopy and atomic force microscopy. Extracellular filaments formed by PDT were analyzed with a tandem imaging approach based on confocal microscopy and atomic force microscopy. Ultrathin filaments that were not visible by confocal microscopy were identified as mi...
Source: Ultramicroscopy - July 23, 2009 Category: Laboratory Medicine Authors: Jung SH, Park JY, Yoo JO, Shin I, Kim YM, Ha KS Tags: Ultramicroscopy Source Type: journals

The effect of surface strain relaxation on HAADF imaging.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this work the effects of strain on high-angle annular dark field (HAADF) images taken in zone axis conditions have been quantitatively studied. In particular, the presence of dark contrast zones in experimental HAADF images of InGaAs-GaAs interfaces is here interpreted in terms of strain relaxation at the surface. The consistence of this assumption is demonstrated by means of experiments and simulations performed for different In compositions, specimen tilt and thickness conditions. It is shown how the HAADF contrast mechanism is related to the bending of the lattice planes in the first surface region. Finally, a ge...
Source: Ultramicroscopy - July 23, 2009 Category: Laboratory Medicine Authors: Grillo V Tags: Ultramicroscopy Source Type: journals

What atomic resolution annular dark field imaging can tell us about gold nanoparticles on TiO(2) (110).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Annular dark field scanning transmission electron microscopy imaging was recently applied to a catalyst consisting of gold nanoparticles on TiO(2) (110), showing directly that the gold atoms in small nanoparticles preferentially attach to specific sites on the TiO(2) (110) surface. Here, through simulation, a parameter exploration of the imaging conditions which maximise the visibility of such nanoparticles is presented. Aberration correction, finite source size and profile imaging are all considered while trying to extracting the maximum amount of information from a given sample. Comment is made on the role of the the...
Source: Ultramicroscopy - July 23, 2009 Category: Laboratory Medicine Authors: Findlay SD, Shibata N, Ikuhara Y Tags: Ultramicroscopy Source Type: journals

A systematic approach to choosing parameters for modelling fine structure in electron energy-loss spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A potential methodology is presented for the systematic prediction of EELS edges using DFT, suitable for codes that calculate ELNES for a specific atom in a unit cell. The method begins with the selection of a unit cell, chosen as the smallest cell that still provides a physically valid representation of the bulk material. Within this small cell, a single electron core-hole is included in the atom for which the EELS ionisation edge is to be calculated. The basis-set size and k-point mesh of the DFT calculation are converged specifically against the predicted EELS result. Subsequently, the cell size is increased until t...
Source: Ultramicroscopy - July 14, 2009 Category: Laboratory Medicine Authors: Seabourne CR, Scott AJ, Brydson R, Nicholls RJ Tags: Ultramicroscopy Source Type: journals

Enhanced imaging in low dose electron microscopy using electron counting.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We compare the direct electron imaging performance at 120keV of a monolithic active pixel sensor (MAPS) operated in a conventional integrating mode with the performance obtained when operated in a single event counting mode. For the combination of sensor and incident electron energy used here, we propose a heuristic approach with which to process the single event images in which each event is renormalised to have an integrated weight of unity. Using this approach we find enhancements in the Nyquist frequency modulation transfer function (MTF) and detective quantum efficiency (DQE) over the corresponding integrating mod...
Source: Ultramicroscopy - July 14, 2009 Category: Laboratory Medicine Authors: McMullan G, Clark AT, Turchetta R, Faruqi AR Tags: Ultramicroscopy Source Type: journals

Calculation of aberration coefficients by ray tracing.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this paper we present an approach for the calculation of aberration coefficients using accurate ray tracing. For a given optical system, intersections of a large number of trajectories with a given plane are computed. In the Gaussian image plane the imaging with the selected optical system can be described by paraxial and aberration coefficients (geometric and chromatic) that can be calculated by least-squares fitting of the analytical model on the computed trajectory positions. An advantage of such a way of computing the aberration coefficients is that, in comparison with the aberration integrals and the differenti...
Source: Ultramicroscopy - July 14, 2009 Category: Laboratory Medicine Authors: Oral M, Lencová B Tags: Ultramicroscopy Source Type: journals

Automated monitoring to reduce electron microscope downtime.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
High-end transmission electron microscopes are complex and sensitive instruments. Failure of one of the external supplies, malfunction of the microscope hardware or maloperation are typical reasons for subsystems to fail. Especially if undiscovered for a longer period of time, this can cause unnecessary downtime, compromising user access and increasing operating costs. Utilizing the software introduced in this article ("MoniTEM"), we have succeeded to reduce downtime of an FEI Tecnai Polara by coupling constant monitoring of critical subsystems with automatic, remote feedback to the system supervisor, ensuring immediat...
Source: Ultramicroscopy - July 14, 2009 Category: Laboratory Medicine Authors: Brunner MJ, Resch GP Tags: Ultramicroscopy Source Type: journals

Advanced thin film technology for ultrahigh resolution X-ray microscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Further progress in the spatial resolution of X-ray microscopes is currently impaired by fundamental limitations in the production of X-ray diffractive lenses. Here, we demonstrate how advanced thin film technologies can be applied to boost the fabrication and characterization of ultrahigh resolution X-ray optics. Specifically, Fresnel zone plates were fabricated by combining electron-beam lithography with atomic layer deposition and focused ion beam induced deposition. They were tested in a scanning transmission X-ray microscope at 1.2keV photon energy using line pair structures of a sample prepared by metalorganic va...
Source: Ultramicroscopy - July 14, 2009 Category: Laboratory Medicine Authors: Vila-Comamala J, Jefimovs K, Raabe J, Pilvi T, Fink RH, Senoner M, Maaßdorf A, Ritala M, David C Tags: Ultramicroscopy Source Type: journals

Proceedings of the 10th International Scanning Probe Microscopy (ISPM) Conference Seattle, Wa, USA, June 22-24, 2008.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Authors: PMID: 19555819 [PubMed - in process] (Source: Ultramicroscopy)
Source: Ultramicroscopy - June 29, 2009 Category: Laboratory Medicine Tags: Ultramicroscopy Source Type: journals

The Manuscripts for these Proceedings were received by the Publisher: beginning of March 2009.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Authors: PMID: 19555820 [PubMed - in process] (Source: Ultramicroscopy)
Source: Ultramicroscopy - June 29, 2009 Category: Laboratory Medicine Tags: Ultramicroscopy Source Type: journals

10(th) International Scanning Probe Microscopy Conference Seattle, Washington, USA June 22-24, 2008.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Authors: PMID: 19555821 [PubMed - in process] (Source: Ultramicroscopy)
Source: Ultramicroscopy - June 29, 2009 Category: Laboratory Medicine Tags: Ultramicroscopy Source Type: journals

Preface.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19339116 [PubMed - in process] (Source: Ultramicroscopy)
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Doktycz MJ, Allison DP Tags: Ultramicroscopy Source Type: journals

Visualization of magnetic domains by near-field scanning microwave microscope.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A near-field scanning microwave microscope (NSMM) system was used for the investigation of magnetic properties of a hard disk (HD) under an external magnetic field. To demonstrate local microwave characterization of magnetic domains by NSMM, we scanned the HD surface by measuring the microwave reflection coefficient S(11) of the NSMM at an operating frequency near 4.4GHz. The NSMM offers a reliable means for quantitative measurement of magnetic domains with high spatial resolution and sensitivity. PMID: 19342175 [PubMed - in process] (Source: Ultramicroscopy)
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Lee K, Melikyan H, Babajanyan A, Sargsyan T, Kim J, Kim S, Friedman B Tags: Ultramicroscopy Source Type: journals

Hydrophobic corn starch thermoplastic films produced by plasma treatment.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Polymer coating technology is currently an important field in science as it can lead to final products with enhanced characteristics characterized by desired bulk and surface properties. Low power plasmas can induce the polymerization of a precursor gas on the substrate surface as well as introduce functional groups under specific plasma conditions. In the present work, we studied the possibility of reducing water sensitivity of corn starch films by sulfur hexafluoride (SF(6)) plasma treatment. Confocal laser microscopy as well as atomic force microscopy was used to observe the main surface modifications and results in...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Bastos DC, Santos AE, da Silva ML, Simão RA Tags: Ultramicroscopy Source Type: journals

Immobilization and characterization of ferritin on gold electrode.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Properties of ferritin, immobilized on dithiobis (N-succinimydyl propionate) (DTSP)-covered gold electrode, in 3-morpholino propanesulfonic acid buffer were investigated by AFM and FE-SEM. Electrochemical properties the ferritin was measured by a cyclic volatammetry. When the potentials of 0.2, 0.34, and 1.0V vs. Ag/AgCl were applied for 15h for the ferritin immobilization, the electrode potential of Fe(II)/Fe(III) in ferritin changed to negative values. Negative electrode potential shift of Fe(II)/Fe(III) in ferritin with respect to the applied potential could be attributed to the stabilized ferritin on DTSP-covered g...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Park CW, Park HJ, Kim JH, Won K, Yoon HH Tags: Ultramicroscopy Source Type: journals

Improvement of KFM performance by intermittent bias application method and by sampling detection of cantilever deflection.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have proposed an intermittent bias application method as well as a sampling detection method of cantilever deflection in Kelvin probe force microscopy (KFM) to improve its performances for surface potential measurements. In the former method, spiky biases, instead of the bias in a sinusoidal waveform normally used in KFM, are intermittently applied to generate electrostatic force at exact moments when the tip approaches the closest position to a sample surface. The latter one, on the other hand, realizes very sensitive detection of the electrostatic force, which is preferable in KFM. Both the dependence of the elect...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Takahashi T, Matsumoto T, Ono S Tags: Ultramicroscopy Source Type: journals

Electrical detection of beta-amyloid (1-40) using scanning tunneling microscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, a vertically configured electrical detection system associated with scanning tunneling microscopy (STM) was used to characterize antigen-antibody binding interactions. The proposed technique can be easily utilized to construct a multiple measurement system in a protein chip. The immunocomplexes used in the model protein comprise beta-amyloid (1-40), corresponding antibody fragments, and gold nanoparticle-antibody conjugates. The electrical tunneling current between the STM tip and these complexes exhibited a peak-like pulse, where the frequency of these pulses was dependent on the surface density of bound co...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Lee JH, Kang DY, Kim SU, Yea CH, Oh BK, Choi JW Tags: Ultramicroscopy Source Type: journals

High-sensitivity detection of proteins using gel electrophoresis and atomic force microscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have developed a method to detect specific proteins with a high sensitivity using a gel electrophoresis method and force measurement of atomic force microscopy (AFM). Biotinylated proteins were separated by electrophoresis and fixed with cross-linking chemicals on the gel, followed by direct force measurement between the biotinylated proteins on the gel and a streptavidin-modified tip of an AFM cantilever. We were able to achieve a high enough sensitivity to detect the picogram order of the biotinylated proteins by evaluating the frequency of the interaction force larger than 100pN in the force profile, which corres...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Sekiguchi H, Hidaka A, Shiga Y, Ikai A, Osada T Tags: Ultramicroscopy Source Type: journals

Nanotribological properties of novel lubricants for magnetic tapes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Two classes of novel lubricants, perfluoropolyethers (PFPE) and ionic liquids (ILs), were deposited on metal film magnetic tapes. The adhesive force and coefficient of friction of lubricated and unlubricated tapes were investigated at the nanoscale with an atomic force microscope (AFM) as a function of various humidity and temperature conditions. Microscale tests with a ball-on-flat tribometer were also performed in order to study the length-scale effects on friction. Wear at ultralow loads was simulated and the lubricant removal mechanism was investigated by monitoring the friction force, surface potential and contact...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Palacio M, Bhushan B Tags: Ultramicroscopy Source Type: journals

Fabrication and characterization of the hierarchical structure for superhydrophobicity and self-cleaning.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Hierarchical roughness is beneficial for the superhydrophobicity. Surfaces with microstructure, nanostructure and hierarchical structure were fabricated by replication of micropattern and self-assembly of hydrophobic alkanes. The fabrication technique used is a low-cost two-step process, which provides flexibility in fabrication of variety of hierarchical structures. Fabricated structures and surface chemistry mimic the hierarchical surfaces of superhydrophobic and self-cleaning plant surfaces. The influence of structure on the superhydrophobicity at different length scales is demonstrated by investigation of contact a...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Bhushan B, Koch K, Jung YC Tags: Ultramicroscopy Source Type: journals

Intrinsic friction analysis-Novel nanoscopic access to molecular mobility in constrained organic systems.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Condensed organic materials designed for nanotechnological applications are impacted significantly by internal and external constraints. Internal constraints are inherent to the molecular architecture, and generally result from direct bonding, electrostatic interactions, or steric effects. Internal constraints can be incorporated a priori into molecular designs, as a prescription for desired material properties. Today's challenge lies in obtaining information about the molecular mobility, in particular, in thin organic structured or unstructured films. A method that has been recently introduced, and is well suited for ...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Knorr DB, Gray TO, Overney RM Tags: Ultramicroscopy Source Type: journals

The number distribution of complex shear modulus of single cells measured by atomic force microscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The viscoelastic properties of a large number of mouse fibroblast NIH3T3 cells (n approximately 130) were investigated by combining atomic force microscopy (AFM) with a microarray technique. In the experiments, the cells were arranged and cultured in the wells of a microarray substrate, and a force modulation mode experiment was used to measure the complex shear modulus, G*, of individual cells in a frequency range 0.5-200Hz. The frequency dependence of G* of the cells exhibited a power-law behavior and similar frequency dependencies have been observed in several cell types cultured on flat substrates. This indicated t...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Hiratsuka S, Mizutani Y, Tsuchiya M, Kawahara K, Tokumoto H, Okajima T Tags: Ultramicroscopy Source Type: journals

A method for fabricating protein patterns on the octadecyltrichlorosialne(OTS) surface through paper swabbing.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A simple protein patterning procedure was developed for fabricating clean protein patterns ranging from nanometer to sub-millimeter scale. A carboxylic acid-terminated chemical pattern was fabricated first through the local probe oxidation on the octadecyltrichlorosilane (OTS) film under 100% relative humidity at the first. After incubating the chemical pattern in a protein solution, the sample was swabbed with a piece of ChemWipe paper to selectively remove the non-specifically adsorbed protein. After the swabbing, only the specifically immobilized protein remained on the surface, forming a protein pattern on the chem...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Gao P, Cai Y Tags: Ultramicroscopy Source Type: journals

Nanoscale film formation of ferritin and its application to biomemory device.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A redox protein, ferritin is used as a functional constituent of the developed biomemory device. The concept of molecular device mainly depends on the solidification of biomolecules of interest and on the realization of properties of molecule immobilized on a selected substrate. Here, we immobilized the biomolecule, ferritin protein on gold substrate using an organic linker 11-mercaptoundecanoic acid (11-MUA). The immobilization of the protein on the gold substrate was confirmed by surface plasmon spectroscopy, Raman spectroscopy, and atomic force microscopy (AFM). The basic two memory functions, reading and writing of...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Kim SU, Lee T, Lee JH, Yagati AK, Min J, Choi JW Tags: Ultramicroscopy Source Type: journals

High-speed atomic force microscope lithography using a piezo tube scanner driven by a sinusoidal waveform.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Improving the throughput of atomic force microscope (AFM) lithography is an important success factor for employing it in nanolithography applications. The conventional motion of the AFM tube scanner is usually driven by triangular-shaped signals, but it is limited in speed due to mechanical instability of the scanner at the turning points. Here, we show that high-speed lithography is achievable using not only a piezo tube driven by a sinusoidal waveform signal but also highly sensitive noble organic resists including a photo acid generator. Cross-linked polymer nanostructures applying sinusoidal waveform driving have a...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Kwon G, Kim SH, Jeong M, Han SH, Choi CS, Han SJ, Hong J, Lee H Tags: Ultramicroscopy Source Type: journals

Effects of dopamine concentration on energy transfer between dendrimer-QD and dye-labeled antibody.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, the effect of dopamine level on this phenomenon was observed using the Forster resonance energy transfer (FRET) phenomenon generated between a donor and acceptor. By confirming the photoluminescence (PL) and lifetime data, it was demonstrated that the degree of energy transfer increased with increasing dopamine concentration. To apply this phenomenon to an optical sensor, a glass surface was modified with a quantum dot (QD)-encapsulated dendrimer, and analyzed using the contact angle and ATR-FTIR. The topology of surface was determined by an atomic force microscope (AFM). PMID: 19359098 [PubMed - in proc...
Source: Ultramicroscopy - June 27, 2009 Category: Laboratory Medicine Authors: Lee KR, Kang IJ Tags: Ultramicroscopy Source Type: journals