The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Tae Joo Shin - One of the best experts on this subject based on the ideXlab platform.
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X‐ray imaging of various biological samples using a phase‐contrast hard X‐ray Microscope
Microscopy research and technique, 2008Co-Authors: Guk Bae Kim, Hwa Shik Youn, Tae Joo Shin, Yae Jin Yoon, Yong Song Gho, Sang Joon LeeAbstract:In this study, we visualized the internal structures of various bio-samples and found the optimum conditions of test samples for the 7 keV hard X-Ray Microscope of the Pohang light source. From the captured X-Ray images, we could observe the intercellular and intracellular structures of dehydrated human cells and mouse tumor tissues without using any staining materials in a spatial resolution better than 100 nm. The metastasized lung tissue, which was several tens of micrometers in thickness, was found to be very well suited to this hard X-Ray Microscope system, because it is nearly impossible to observe such a nontransparent and thick sample with a high spatial resolution better than 100 nm using any Microscopes such as a soft X-Ray Microscope, an optical Microscope, or an electron Microscope. Microsc. Res. Tech., 2008. © 2008 Wiley-Liss, Inc.
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A study of the human hair structure with a Zernike phase contrast X‐ray Microscope
Journal of Microscopy, 2007Co-Authors: Hwa Shik Youn, Tae Joo ShinAbstract:Summary We have observed the internal structure of human hair shafts with a transmission Zernike phase contrast hard X-Ray Microscope. Due to the high spatial resolution and the high contrast of the Microscope, we could image scales, macrofibrils, medulla and melanin without staining. The structure of a black hair shaft is compared with that of a white one.
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A study of the human hair structure with a Zernike phase contrast X-Ray Microscope.
Journal of microscopy, 2007Co-Authors: Hwa Shik Youn, Tae Joo ShinAbstract:We have observed the internal structure of human hair shafts with a transmission Zernike phase contrast hard X-Ray Microscope. Due to the high spatial resolution and the high contrast of the Microscope, we could image scales, macrofibrils, medulla and melanin without staining. The structure of a black hair shaft is compared with that of a white one.
Hwa Shik Youn - One of the best experts on this subject based on the ideXlab platform.
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Observation of bio-fibres with a hard X-Ray Microscope
Journal of Physics: Conference Series, 2009Co-Authors: Hwa Shik YounAbstract:PLS (Pohang Light Source) hard X-Ray Microscope is briefly introduced. Zernike phase contrast is evaluated with images of polymer structures with various thicknesses. Images of bio-fibres taken with Zernike phase contrast are shown
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X‐ray imaging of various biological samples using a phase‐contrast hard X‐ray Microscope
Microscopy research and technique, 2008Co-Authors: Guk Bae Kim, Hwa Shik Youn, Tae Joo Shin, Yae Jin Yoon, Yong Song Gho, Sang Joon LeeAbstract:In this study, we visualized the internal structures of various bio-samples and found the optimum conditions of test samples for the 7 keV hard X-Ray Microscope of the Pohang light source. From the captured X-Ray images, we could observe the intercellular and intracellular structures of dehydrated human cells and mouse tumor tissues without using any staining materials in a spatial resolution better than 100 nm. The metastasized lung tissue, which was several tens of micrometers in thickness, was found to be very well suited to this hard X-Ray Microscope system, because it is nearly impossible to observe such a nontransparent and thick sample with a high spatial resolution better than 100 nm using any Microscopes such as a soft X-Ray Microscope, an optical Microscope, or an electron Microscope. Microsc. Res. Tech., 2008. © 2008 Wiley-Liss, Inc.
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A study of the human hair structure with a Zernike phase contrast X‐ray Microscope
Journal of Microscopy, 2007Co-Authors: Hwa Shik Youn, Tae Joo ShinAbstract:Summary We have observed the internal structure of human hair shafts with a transmission Zernike phase contrast hard X-Ray Microscope. Due to the high spatial resolution and the high contrast of the Microscope, we could image scales, macrofibrils, medulla and melanin without staining. The structure of a black hair shaft is compared with that of a white one.
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A study of the human hair structure with a Zernike phase contrast X-Ray Microscope.
Journal of microscopy, 2007Co-Authors: Hwa Shik Youn, Tae Joo ShinAbstract:We have observed the internal structure of human hair shafts with a transmission Zernike phase contrast hard X-Ray Microscope. Due to the high spatial resolution and the high contrast of the Microscope, we could image scales, macrofibrils, medulla and melanin without staining. The structure of a black hair shaft is compared with that of a white one.
Hans M. Hertz - One of the best experts on this subject based on the ideXlab platform.
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The Stockholm laboratory cryo X-Ray Microscope : towards cell-cell interaction studies
Journal of Physics: Conference Series, 2013Co-Authors: Emelie Fogelqvist, M. Selin, Athanasia E. Christakou, Dale H. Martz, Hans M. HertzAbstract:We describe recent improvements in the Stockholm laboratory X-Ray Microscope and the first experiments aiming towards studies of cell-cell interaction. The shorter exposure time due to a higher brightness laser-plasma source will become of large importance for tomography while the reproducible cryo preparation of few-cell samples is essential for the interaction studies.
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compact x ray Microscope for the water window based on a high brightness laser plasma source
Optics Express, 2012Co-Authors: Herbert Legall, M. Selin, Per Takman, Ulrich Vogt, G Blobel, H Stiel, W Sandner, Christian Seim, Dale Martz, Hans M. HertzAbstract:We present a laser plasma based X-Ray Microscope for the water window employing a high-average power laser system for plasma generation. At 90 W laser power a brightness of 7.4 x 1011 photons/(s x sr x μm2) was measured for the nitrogen Lyα line emission at 2.478 nm. Using a multilayer condenser mirror with 0.3 % reflectivity 106 photons/(μm2 x s) were obtained in the object plane. Microscopy performed at a laser power of 60 W resolves 40 nm lines with an exposure time of 60 s. The exposure time can be further reduced to 20 s by the use of new multilayer condenser optics and operating the laser at its full power of 130 W.
Y. Iketaki - One of the best experts on this subject based on the ideXlab platform.
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A compact Schwarzschild soft X‐ray Microscope with a laser‐produced plasma source
Journal of Microscopy, 1993Co-Authors: Y. Horikawa, K. Nagai, S. Mochimaru, Y. IketakiAbstract:Summary A compact Schwarzschild soft X-Ray Microscope using a laser-produced plasma soft X-Ray source has been developed. The laser-produced plasma source, which is small but of high brilliance, has made it possible to use the soft X-Ray Microscope in a small laboratory. The Microscope is composed of a Schwarzschild objective and a grazing incidence mirror condenser. Image contrast for biological specimens in soft X-Ray regions is investigated briefly. It is possible to observe the fine structures of a thin specimen at a wavelength of 15 nm; at this wavelength high-contrast images of biological specimens have been obtained with a single laser shot of pulse width of 8 ns at a resolution of 0·3 μm. The resolution of the system is limited by the detector.
Chris Jacobsen - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Phase Imaging with a Scanning Transmission X-Ray Microscope
Physical review letters, 2008Co-Authors: M. D. De Jonge, Benjamin Hornberger, Christian Holzner, D. Legnini, D. Paterson, Ian Mcnulty, Chris Jacobsen, Stefan VogtAbstract:We obtain quantitative phase reconstructions from differential phase contrast images obtained with a scanning transmission X-Ray Microscope and 2.5 keV x rays. The theoretical basis of the technique is presented along with measurements and their interpretation.
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Development of a Cryo Scanning Transmission X-Ray Microscope at the NSLS
X-Ray Microscopy and Spectromicroscopy, 1998Co-Authors: Jörg Maser, Chris Jacobsen, Janos Kirz, A. Osanna, Steve Spector, Steve Wang, Jan WarnkingAbstract:We have developed a cryo Scanning Transmission X-Ray Microscope at the X1A beamline at the NSLS. The system is designed to image hydrated biological objects of a thickness of several micrometers at temperatures of around 110 K at a resolution of ultimately 30 nm or less. A description of the setup of the cryo-STXM is given. We have started to commission the system and present some results, including first images of biological samples.
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NSLS X 1AL scanning X-Ray Microscope
Proceedings annual meeting Electron Microscopy Society of America, 1993Co-Authors: Chris Jacobsen, S. Williams, Janos Kirz, Xiaodong Zhang, S. Lindaas, Sue Wirick, Erik Anderson, Dieter Kern, Harald AdeAbstract:Soft x rays are well suited to the study of low-Z elements in 0.1-10 μm thick specimens. A variety of soft X-Ray Microscopes are now under operation, several of which achieve image resolutions of 0.03-0.1 μm. Scanning X-Ray Microscopes offer some desirable charactistics: they are able to operate in a variety of imaging modes, including transmission, luminescence, dark field, and photoemission, and they enable minimum dose imaging by utilizing highly efficient photon counting detectors and placing moderate efficiency optics between the source and specimen rather than between specimen and detector.The NSLS X-1AL scanning X-Ray Microscope uses an undulator at the National Synchrotron Light Source at Brookhaven National Laboratory as a tunable, high-brightness soft X-Ray source. Monochromatized, spatially coherent illumination is focussed by a Fresnel zone plate fabricated using electron beam lithography. The sample is scanned through the 0.055 μm Rayleigh resolution focal spot using stepping motors (for large scans) and linearized piezos.
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Imaging with the Brookhaven Scanning Transmission X-Ray Microscope
Synthetic Microstructures in Biological Research, 1992Co-Authors: S. Williams, Chris Jacobsen, Janos Kirz, Xiaodong ZhangAbstract:Current X-Ray Microscopes offer the possibility of imaging unstained, unfixed, unsectioned, micron thick, wet biological specimens with a resolution approaching 30nm. Because the absorption of X-Rays depends primarily on the elemental composition of the specimen, the images lend themselves to quantitative analysis of sample structure. The Scanning Transmission X-Ray Microscope at Brookhaven National Lab uses a zone plate to form a focused probe through which the sample is scanned. The modulation transfer function of the Microscope has been measured and agrees well with calculations based on the zone plate construction. This knowledge permits recovery of the intrinsic contrast of object features using image deconvolution. Current zone plates provide a Rayleigh resolution of 50 nm, and the ability to see 30 nm objects. This resolution has been achieved in practice for images of test specimens and dried biological specimens, where high doses can be tolerated. Single images of wet V. faba chromosomes show 80 nm resolution. Subsequent images show that specimens were degraded by radiation damage following the initial exposure. Many researchers have used the Brookhaven STXM for problems in neurobiology, protein transport, elemental imaging, and chromosome structure.
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Diffraction-limited imaging in a scanning transmission X-Ray Microscope
Optics Communications, 1991Co-Authors: Chris Jacobsen, M. T. Browne, S. Williams, Erik H. Anderson, C. J. Buckley, Dieter P. Kern, Janos Kirz, Mark L. Rivers, Xiaodong ZhangAbstract:Abstract We report the characterization of a scanning transmission X-Ray Microscope which makes use of an undulator X-Ray source, a high resolution scanning stage, and a 45 nm outer zone width, > 10% diffraction efficiency Fresnel zone plate as the probe-forming optic at soft X-Ray wavelengths (typically 3.64 nm). The modulation transfer function of the instrument is in good agreement with theory; it remains above 0.1 to spatial frequencies corresponding to structures as small as 25 nm. This spatial frequency limit is the best obtained in any soft X-Ray Microscope, and is about a factor of ten better than what is attained in conventional or confocal visible light Microscopes. By deconvolving the zone plate point spread function from the image, the Microscope has been used to resolve 36 nm features in a gold test object. The Microscope is used primarily for the study of thick, hydrated biological specimens with minimal radiation dose.
