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Ptychography has emerged as a nondestructive tool to quantitatively study extended samples at a high spatial resolution. In this manuscript, we report on recent developments from our team. We have combined cryo ptychography and fluorescence microscopy to provide simultaneous views of ultrastructure and elemental composition, we have developed multi-GPU parallel computation to speed up ptychographic reconstructions, and we have implemented fly-scan ptychography to allow for faster data acquisition. We conclude with a discussion of future challenges in high-resolution 3D ptychography. [ABSTRACT FROM AUTHOR]

Trace elements, particularly metals, play very important roles in biological systems. Synchrotron-based hard X-ray fluorescence microscopy offers the most suitable capabilities to quantitatively study trace metals in thick biological samples, such as whole cells and tissues. In this manuscript, we have demonstrated X-ray fluorescence imaging of frozen-hydrated whole cells using the recent developed Bionanoprobe (BNP). The BNP provides spatial resolution down to 30 nm and cryogenic capabilities. Frozen-hydrated biological cells have been directly examined on a sub-cellular level at liquid nitrogen temperatures with minimal sample preparation. [ABSTRACT FROM AUTHOR]

A prominent feature of soil colloids is their huge specific surface. It determines colloidal properties such as adsorption capacity or diffusion. The colloidal interactions differ significantly from the behavior of the same materials in a bulk system. Interactions in the colloidal regime are crucial, for example, for the transport and release of nutrients and toxicants in soils, which then influences directly the growth of plants. However, there is still a need for more analytical resources to study those interactions. To reveal the correlation of the particular trace elements and their distribution in correlation to colloidal interactions as well as changing pH values, experiments at the hard x-ray fluorescence microprobe at beamline 2-ID-E of the Advanced Photon Source (APS), were performed with colloidal clay and soil samples in an aqueous environment as naturally relevant. To obtain further spatial information, stereo imaging has been used. To study the dynamical behavior of these colloidal suspensions at changing pH, a wet sample chamber allowing in situ manipulation was developed and utilized. [ABSTRACT FROM AUTHOR]

We present in this paper a novel methodology that combines scanning x-ray fluorescencee microscopy and atomic force microscopy. The combination of these two techniques allows the determination of a concentration map of Mg in whole (not sectioned) cells. [ABSTRACT FROM AUTHOR]

We are developing TiO2 nanoconjugates that can be used as therapeutic and diagnostic agents. Nanoscale TiO2 can be surface conjugated with various molecules and has the unique ability to induce the production of reactive oxygen species after radiation activation. One way to improve the potential clinical usefulness of TiO2 nanoparticles is to control their delivery to malignant cells by targeting them to cancer-cell-specific antigens. Epidermal growth factor receptor (EGFR) is one potential target that is enriched in epithelial cancers and is rapidly internalized after ligand binding. Hence, we have synthesized TiO2 nanoparticles and functionalized them with a short EGFR-binding peptide to create EGFR-targeted NCs. X-ray fluorescence microscopy was used to image nanoconjugates within EGFR-positive HeLa cells. Further labeling of fixed cells with antibodies against EGFR and Protein A nanogold showed that TiO2 nanoconjugates can colocalize with receptors at the cell's plasma membrane. Interestingly, with increased incubation times, EGFR-targeted nanoconjugates could also be found colocalized with EGFR within the cell nucleus. This suggests that EGFR-targeted nanoconjugates can bind the receptor at the cell membrane, which leads to the internalization of NC-receptor complexes and the subsequent transport of nanoconjugates into the nucleus. [ABSTRACT FROM AUTHOR]

We present the data, and modeling and analysis results from the photometric monitoring of five planetary transits of HD 209458 using the Fine Guidance Sensors (FGS) onboard the Hubble Space Telescope (HST). We have now included the output from all four FGS photometers in our data reduction and analysis increasing our S/N over our previous results. We have modeled the transits as an opaque spherical planet in a circular orbit about a limb darkened spherical star and simultaneously fit the model to the FGS data and published STIS transit data. The measured light curves show small features, a fraction of the transit depth. Some of these faint bumps and ripples appear to be real. We present an analysis of the FGS transit light curves, showing the results of the model fitting and a search for a possible planetary satellite. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We are developing a new hard x-ray nanoprobe beamline with 30 nm resolution at the Advanced Photon Source (APS). Imaging and spectroscopy at this resolution level require staging of x-ray optics and specimens with a mechanical repeatability of better than 10 nm. We have developed a prototype instrument with a novel interferometrically controlled scanning stage system. The system consists of nine DC-motor-driven stages, four picomotor-driven stages, and two PZT-driven stages. An APS-designed custom-built laser Doppler displacement meter system provides two-dimensional differential displacement measurement with subnanometer resolution between the zone-plate x-ray optics and the sample holder. Also included is the alignment and stable positioning of two stacked zone plates for increasing the focusing efficiency. The entire scanning system was designed with high stiffness, high repeatability, low drift, flexible scanning schemes, and possibility of fast feedback for differential motion. Designs of the scanning stage system, as well as preliminary mechanical test results, are presented in this paper. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

The planned Center for Nanoscale Materials (CNM) at Argonne National Laboratory is aimed at the development and study of the properties of nanomaterials and nanodevices. As part of the characterization instruments at CNM, we are developing a new hard x-ray nanoprobe beamline at the Advanced Photon Source. The beamline will provide microscopy and spectroscopy for photon energies from 3 keV to 30 keV. Hard x-ray zone plates will be used to achieve a spatial resolution of 30 nm in the 3 – 10 keV region. Two operational modes will combine the speed of a transmission x-ray microscope with the analytic capabilities of a hard x-ray microprobe. The major operation mode will be a scanning probe mode, where spatially coherent radiation is focused into a diffraction-limited spot to excite secondary signals in the specimen. This will allow elemental mapping and spectroscopy at high sensitivity using x-ray fluorescence, or strain contrast imaging using x-ray diffraction. A secondary mode will use partially coherent radiation to provide transmission imaging in absorption and phase contrast for photon energies between 3 – 10 keV. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We report the results of a new experimental search for the Pauli-forbidden 1s[sup 4] state of Be, denoted by Be'. Using the Accelerator Mass Spectrometer facility at Purdue, we set limits on the abundance of Be' in metallic Be, Be ore, natural gas, and air (10[sup -14]). Our results improve on those obtained in a previous search for Be' by a factor of approximately 300. We report the results of a new experimental search for the Pauli-forbidden 1s[sup 4] state of Be, denoted by Be'. Using the Accelerator Mass Spectrometer facility at Purdue, we set limits on the abundance of Be' in metallic Be, Be ore, natural gas, and air (10[sup -14]). Our results improve on those obtained in a previous search for Be' by a factor of approximately 300. [ABSTRACT FROM AUTHOR]

In X-ray microscopy different proteins are not readily distinguishable. However, in cell biology it is often desirable to localize single proteins, e.g., inside the cell nucleus. This can be achieved by immunogold labeling. Colloidal gold conjugated antibodies are used to mark the protein specifically. With silver solution these are enlarged so as to heighten their contrast. The strong absorption of silver allows easy visualization of the label in the nuclei. In this study male specific lethal 1 protein in male Drosophila melanogaster cells was labeled. This protein forms, together with four other proteins, a complex that is associated with the male X chromosome. It regulates dosage compensation by enhancing X-linked gene transcription in males. Room temperature and cryo transmission X-ray microscopic images (taken with the Göttingen TXM at BESSY) of these labeled cells are shown. Confocal laser scan microscopy ascertains the correct identification of the label in the X-ray micrographs, and allows comparison of the structural information available from both instruments. [ABSTRACT FROM AUTHOR]