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Journal Articles

Correlative imaging of live biological cells with a soft X-ray microscope and a fluorescence microscope

Kado, Masataka; Kishimoto, Maki; Tamotsu, Satoshi*; Yasuda, Keiko*; Aoyama, Masato*; Tone, Shigenobu*; Shinohara, Kunio*

AIP Conference Proceedings 1696, p.020019_1 - 020019_4, 2016/01

 Times Cited Count:2 Percentile:80.58

Soft X-ray microscope is a very powerful tool to observe cellular organelles of living biological cells and many works have demonstrated imaging of inner structures of the cells. However the inner structures are very complicated and it is difficult to identify the organelles obtained with the soft X-ray microscopes. We have proposed a hybrid imaging method with a soft X-ray microscope and a fluorescence microscope that is to observe the same biological cells with the both microscopes at the same time. Using the information of the cellular organelles obtained with the fluorescence microscope, inner structures obtained with the soft X-ray microscope are accurately identified. We have observed living biological cells by the hybrid imaging method. Since the soft X-ray microscope has higher spatial resolution than that of the fluorescence microscope, fine structures of the cellular organelles in the living biological cells were discussed.

Journal Articles

Biological and medical application of intense electromagnetic radiation

Kado, Masataka; Katsuki, Sunao*

Reza Kenkyu, 42(1), p.40 - 44, 2014/01

This paper describes the biological effect of an intense pulsed electric field and electromagnetic radiation that varies by frequency band. A field with less frequency than 1 MHz provides an electrical stress to the plasma membrane, but that with higher frequency is likely to affect the intracellular components. A laser plasma soft X-ray microscope, which is a combination of highly intense laser plasma soft X-ray sources and a contact type soft X-ray microscope, has been developed. The laser plasma soft X-ray microscope captures an X-ray image of live hydrated biological cells with 80-nm spatial resolution in a 600-ps time duration. Cellular organelles such as chromatin, mitochondria and actin filaments have been observed with the laser plasma soft X-ray microscope in combination with a fluorescence microscope to identify cellular organelles. We also observed such life phenomenon as an apoptotic process and detailed structural deformation.

Journal Articles

In situ observation of cellular organelles with a contact X-ray microscope

Kado, Masataka; Kishimoto, Maki; Tamotsu, Satoshi*; Yasuda, Keiko*; Shinohara, Kunio*

Journal of Physics; Conference Series, 463, p.012056_1 - 012056_4, 2013/10

 Times Cited Count:13 Percentile:97.61

A contact X-ray microscope coupled with a high intense laser plasma soft X-ray source has been developed and in situ observations of cellular organelles have been conducted. The soft X-ray source were generated by a high power laser pulse onto a thin foiled gold target at the photon numbers of 1.3$$times$$10$$^{15}$$ photons/sr to be able to capture an image of live wet biological cells. The cells were cultured on PMMA photoresists that were formed on transparent glass plates to make optical microscope observation possible. The cells were observed by both of optical microscope and soft X-ray microscope. The obtained soft X-ray images were directly compared with corresponding fluorescent optical images. Cellular organelles such as mitochondria and cytoskeleton in the soft X-ray images were identified referencing the information obtained from the fluorescent images.

Journal Articles

Imaging of fine structures of cellular organelles in hydrated biological cells by a soft X-ray microscope combined with a fluorescence microscope

Kado, Masataka; Kishimoto, Maki; Tamotsu, Satoshi*; Yasuda, Keiko*; Aoyama, Masato*; Shinohara, Kunio*

Proceedings of SPIE, Vol.8849, p.88490C_1 - 88490C_7, 2013/09

 Times Cited Count:1 Percentile:59.67

We have proposed to use a fluorescence microscope to identify the cellular organelles in the images obtained with the soft X-ray microscope observing the same cells with both microscopes. The cells were stained with several fluorescent dyes such as Mito-tracker, Phalloidin, and DAPI and after taking many fluorescence images of cellular organelles the cells were exposed to the flash soft X-rays. The obtained soft X-ray images and fluorescence images of the cells were directly compared and each of the cellular organelles such as mitochondria, actin filaments, and chromosomes in the soft X-ray images was clearly identified. Since the soft X-ray microscope has higher spatial resolution than that of the fluorescence microscope, fine structures of the cellular organelles in the hydrated biological cells were observed for the first time.

Journal Articles

Observation of inside structures of live biological cells by laser plasma X-ray microscope

Kado, Masataka

Isotope News, (700), p.8 - 11, 2012/08

Soft X-ray microscope is expected as a powerful tool to observe cellular organelles and to investigate radiation effects on biological cells. However in vivo observation of cellular organelles were not realized because long exposure time was needed due to insufficient X-ray intensity. Combining high intense soft X-ray sources, which were generated by irradiating high power laser onto thin foil gold target, to contact X-ray microscopy we have developed a laser plasma soft X-ray microscope which can observe cellular organelles of live biological cells with high spatial resolution. As a result we have observed mitochondria surrounding nucleus and chromatin structures inside.

Journal Articles

Development of single shot soft X-ray contact microscopy system for nano-scale dynamics measurement of living biological specimen

Kishimoto, Maki; Kado, Masataka; Ishino, Masahiko; Tamotsu, Satoshi*; Yasuda, Keiko*; Shinohara, Kunio*

AIP Conference Proceedings 1465, p.43 - 47, 2012/07

 Times Cited Count:6 Percentile:91.07

We have been developing a picosecond single shot soft X-ray contact microscopy system for observing the nanometer-scale inner structure of the living biological specimen in a hydrated condition. The microscopy system consists of an intense IR pump laser system for generating soft X-rays and X-ray microscope chamber. The pump laser system employs OPCPA technique to generate water-window X-rays effectively. The X-ray microscope chamber is composed of a vacuum chamber, a focusing lens, a metal film target, an in-vacuum type sample holder. The soft X-rays from the laser-induced plasma generated by pump laser pulse illuminates bio-specimens on the PMMA photo resist set in the in-vacuum sample holder. The photo resist is developed and the X-ray transmission imageis read out by AFM. We took X-ray images of hydrated Leydig cells from mouse testicle and demonstrated that the developed X-ray microscopy system has a spatial resolution of about 100 nm.

Journal Articles

Observation of organelle by a laser plasma X-ray microscope

Kado, Masataka; Kishimoto, Maki; Ishino, Masahiko; Tamotsu, Satoshi*; Yasuda, Keiko*; Shinohara, Kunio*

AIP Conference Proceedings 1465, p.246 - 250, 2012/07

 Times Cited Count:5 Percentile:87.84

Contact X-ray microscopy has a potential to image wet biological specimens in natural condition. It is very important to identify obtained features in the X-ray images, since X-ray microscopes have potential to image features that have not been visualized yet. We have proposed to compare the X-ray images of the biological specimens with the fluorescence images and to identify the features found in the X-ray images based on the features found in the fluorescence images. Comparing the X-ray images to the fluorescence images of the set biological cells, fine structures of the mitochondria in the X-ray images have been able to be identified.

Journal Articles

Source development and novel applications of laser-driven plasma X-ray lasers in JAEA

Kawachi, Tetsuya; Hasegawa, Noboru; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Oba, Toshiyuki; Kaihori, Takeshi; Kishimoto, Maki; Ochi, Yoshihiro; Tanaka, Momoko; et al.

X-Ray Lasers 2010; Springer Proceedings in Physics, Vol.136, p.15 - 24, 2011/12

This paper reviews recent improvement in the source development of laser-driven X-ray lasers and the applications in the research fields of material science, laser processing, X-ray imaging, and radiation damage in biological cells. In the application for material science, we have firstly observed temporal correlation between the domain structures of ferro-electric substance under the Curie temperature. In the laser processing, new X-ray laser interferometer reveals us the nano-scale surface distortion of substance pumped by a femto-second optical pulse. In the X-ray diffraction image, we have taken several static images of micro-structure of samples: now we are trying to extend the objective to nano-scale dynamics using pump and probe method. In the radiation damage of biological cells, we observed double strand break in DNA using X-ray laser exposure; this results are compared with the case using incoherent several KeV X-ray exposure.

Journal Articles

Development of the X-ray interferometer and the method of spatial and temporal synchronization of XRL and optical pulse

Hasegawa, Noboru; Ochi, Yoshihiro; Kawachi, Tetsuya; Terakawa, Kota*; Tomita, Takuro*; Yamamoto, Minoru; Nishikino, Masaharu; Oba, Toshiyuki; Kaihori, Takeshi; Imazono, Takashi; et al.

X-Ray Lasers 2010; Springer Proceedings in Physics, Vol.136, p.353 - 358, 2011/12

The understanding of the dynamics of the initial process is important for the micro processing and welding by the ultra-short laser pulse. The X-ray laser is suitable for probing this initial process because it has short wavelength (Ni-like Ag, 13.9 nm) and short duration (7 ps). For this investigation, the origin of time of the pumping pulse is quite important. In this study, we used the scintillation plate and the plasma gate technique to realize the spatial and temporal synchronization of the pump and probe pulses. For the spatial alignment, a CsI scintillation plate that was set at the sample position was illuminated by both the X-ray laser pulse, and the fluorescence light were detected by the CCD camera. For the temporal synchronization, we set a thin foil at the sample position. We measured the transmission of the X-ray laser while changing a temporal delay of the pumping laser with respect to the time of X-ray laser pulse to obtain the origin of the irradiation time.

Journal Articles

Observation of organelles in Leydig cells by contact soft X-ray microscopy with a laser plasma X-ray source

Kado, Masataka; Ishino, Masahiko; Tamotsu, Satoshi*; Yasuda, Keiko*; Kishimoto, Maki; Nishikino, Masaharu; Kinjo, Yasuhito*; Shinohara, Kunio*

AIP Conference Proceedings 1365, p.391 - 394, 2011/09

 Times Cited Count:6 Percentile:89.64

Contact X-ray microscopy has achieved a single-shot imaging of wet biological specimens in natural condition and succeeded in imaging live mouse macrophages with hair-like structures, which was not observed before. It is very important to identify obtained features in the X-ray images, since X-ray microscopes have potential to image features that have not been visualized yet. Here, we demonstrate to image the same biological specimens both by confocal laser microscopy and soft X-ray microscopy. Staining biological specimens with well-established techniques makes easy to identify features in the fluorescence images obtained with confocal laser microscope. Comparing the X-ray images of the specimens with the fluorescence images, features found in the fluorescence images could also be identified in the X-ray images. Comparing the X-ray images to the fluorescence images, fine structures of the actin filaments in the X-ray images were identified.

Journal Articles

Development of a specimen holder combined with ultra thin film laser plasma X-ray source for compact contact-type soft X-ray microscope to observe hydrated living biologocal cells

Ishino, Masahiko; Kado, Masataka; Shinohara, Kunio*; Yamamoto, Yoshimasa*; Hirai, Itaru*; Kishimoto, Maki; Nishikino, Masaharu; Hasegawa, Noboru; Tamotsu, Satoshi*; Yasuda, Keiko*; et al.

Proceedings of SPIE Europe Optics + Optoelectronics 2011, Vol.8139, p.81390R_1 - 81390R_8, 2011/09

 Times Cited Count:0 Percentile:0.01

Ultra thin gold films are favorable laser plasma targets for a soft X-ray microscopy, because the thin films emit intense soft X-rays at the wavelength of water window region. Using rear side emissions, the distance between the X-ray source and the specimens can be reduced so that the X-ray flux on specimens increases. The microscope system can be designed to be compact when the specimen holder and X-ray source are combined in one piece. The biological specimen holder combined with an ultra thin film target has been developed. This X-ray microscope system needs not any X-ray optics which causes a decrease in X-ray photons for imaging. X-ray images of hydrated living cells have been obtained successfully by use of the newly developed specimen holder. Specimen holder combined with plasma X-ray source will be a key component of a compact soft X-ray microscope using in a laboratory.

Journal Articles

Flash imaging of fine structures of cellular organelles by contact X-ray microscopy with a high intensity laser plasma X-ray source

Kado, Masataka; Ishino, Masahiko; Kishimoto, Maki; Tamotsu, Satoshi*; Yasuda, Keiko*; Kinjo, Yasuhito*; Shinohara, Kunio*

Proceedings of SPIE Europe Optics + Optoelectronics 2011, Vol.8139, p.81390O_1 - 81390O_7, 2011/09

Laser plasma X-ray sources have high intensity and short pulse duration, and are suitable for X-ray microscopy in biology. They make wet live biological specimens possible to be imaged with a single shot X-ray exposure and several works have been done to image them. However there were no reports on the imaging of fine structures of cellular organelles in a live biological cell since higher X-ray intensity is needed for it. We have developed a high intensity laser plasma X-ray source, cooperating it with contact X-ray microscopy, and observed fine structures of cellular organelles in a wet biological cells. Comparing the X-ray images and the fluorescence images of cellular organelles such as actin filaments and mitochondria we have been clearly able to identify organelles in the X-ray images and observed fine structures.

Journal Articles

Observation of actin filaments in Leydig cells with a contact-type soft X-ray microscope with laser plasma X-ray source

Kado, Masataka; Ishino, Masahiko; Tamotsu, Satoshi*; Yasuda, Keiko*; Kishimoto, Maki; Nishikino, Masaharu; Kinjo, Yasuhito*; Shinohara, Kunio*

Denki Gakkai Rombunshi, C, 130(10), p.1774 - 1778, 2010/10

Actin filaments in Leydig cells from mouse testes have been observed with a contact-type soft X-ray microscope with laser plasma X-ray source. The Leydig cells were fixed with paraformaldehyde, stained with Phalloidin, and observed with a confocal laser microscope prior to the observation with X-ray microscope. Obtained images by both of the confocal laser microscopy and the X-ray microscopy were directly compared and revealed that not only position of actin filaments but also the shapes can be identified each other. The actin filaments in the X-ray images were clearly recognized and their structures were obtained in more detail compared to those in the confocal laser microscope images.

Journal Articles

Observations of the intense soft X-ray emissions from ultra thin Au films irradiated with high contrast laser pulses

Ishino, Masahiko; Kado, Masataka; Nishikino, Masaharu; Shinohara, Kunio*; Tamotsu, Satoshi*; Yasuda, Keiko*; Hasegawa, Noboru; Kishimoto, Maki; Oba, Toshiyuki; Kawachi, Tetsuya

Proceedings of SPIE, Vol.7589, p.75891B_1 - 75891B_8, 2010/02

 Times Cited Count:2 Percentile:75.92

Soft X-ray microscopes operating in the water window are capable of imaging living hydrated biological specimens. Laser produced plasmas are attractive soft X-ray sources, because of their short duration time. Based on the minimum dose calculation, soft X-ray photons more than 10$$^{5}$$ photons/$$mu$$m$$^{2}$$ at the sample surface are needed to acquire an image of the biological specimens with spatial resolution up to 100 nm. The observations of soft X-ray emissions from laser produced plasmas using ultra thin film targets have been carried out. Au thin films were irradiated by a high contrast Nd:glass laser pulses. The spectral properties of emitted soft X-rays were monitored by an X-ray spectrograph from the rear side with respect to the surface of laser irradiation. The observed emission intensities had an obvious dependence on the film thickness, and the most intense emissions were obtained at the thickness of 28 nm. The experimental results have suggested that the most of the laser energy irradiated is absorbed by the film target, and it is resulted an efficient energy deposition from laser to X-rays.

Journal Articles

A Novel technique for monitoring the reproducibility of laser tape-target interactions using an X-ray pinhole camera

Ogura, Koichi; Fukumi, Atsushi*; Li, Z.*; Orimo, Satoshi; Sagisaka, Akito; Nishiuchi, Mamiko; Kado, Masataka; Mori, Michiaki; Yogo, Akifumi; Hayashi, Yukio; et al.

Journal of the Vacuum Society of Japan, 52(10), p.570 - 574, 2009/10

For accurate control of relativistic laser-plasma interaction under the repetitive operation, we have to measure and control the laser irradiation conditions such as laser parameters, the target shooting accuracy and so on as well as measuring proton parameter on each laser shot. The displacement of the laser shooting position on a tape target, that are used in the high energy proton generation using an ultra-short Ti:sapphire laser system, is measured by observing an X-ray image from laser plasma with an X-ray pinhole camera for each laser shot. The displacement of the shooting position on the target is about 20micron and the accuracy of the target positioning is within 20micron which is small enough for present laser focusing optics with an F number of 3.6 (f=179mm). The technique contributes to accurate control of a repetitive laser driven proton accelerators.

Journal Articles

Generation of stable and low-divergence 10-MeV quasimonoenergetic electron bunch using argon gas jet

Mori, Michiaki; Kondo, Kiminori; Mizuta, Yoshio*; Kando, Masaki; Kotaki, Hideyuki; Nishiuchi, Mamiko; Kado, Masataka; Pirozhkov, A. S.; Ogura, Koichi; Sugiyama, Hironori*; et al.

Physical Review Special Topics; Accelerators and Beams, 12(8), p.082801_1 - 082801_5, 2009/08

 Times Cited Count:21 Percentile:77.68(Physics, Nuclear)

The pointing stability and divergence of a quasimonoenergetic electron bunch generated in a self-injected laser-plasma acceleration regime using 4 TW laser is studied. A pointing stability of 2.4 mrad root-mean-square (RMS) and a beam divergence of 10.6 mrad (RMS) were obtained using an argon gas-jet target for 50 sequential shots, while these values were degraded by a factor of three at the optimum condition using helium. The peak electron energies were 8.5$$pm$$0.7 MeV and 24.8$$pm$$3.6 MeV using argon and helium, respectively. The experimental results indicate that the different propagation condition could be generated with the different material, although it is performed with the same irradiation condition.

Journal Articles

Experimental and computational characterization of hydrodynamic expansion of a preformed plasma from thin-foil target for laser-driven proton acceleration

Sagisaka, Akito; Nagatomo, Hideo*; Daido, Hiroyuki; Pirozhkov, A. S.; Ogura, Koichi; Orimo, Satoshi; Mori, Michiaki; Nishiuchi, Mamiko; Yogo, Akifumi; Kado, Masataka

Journal of Plasma Physics, 75(5), p.609 - 617, 2009/06

 Times Cited Count:5 Percentile:22.21(Physics, Fluids & Plasmas)

We characterize the electron density distributions of preformed plasma for laser-accelerated proton generation. The preformed plasma of a thin-foil target is generated by prepulse and ASE of a high-intensity Ti:sapphire laser and is measured with an interferometer using a second harmonic probe beam. High-energy protons are obtained by reducing the size of the preformed plasma by changing the ASE duration before main pulse at the front side of the target. Simulation results with two-dimensional radiation hydrodynamic code are close to the experimental results for low-density region $$sim$$4$$times$$10$$^{19}$$ cm$$^{-3}$$ at the front side.

Journal Articles

Characterization of an intense laser-produced preformed plasma for proton generation

Sagisaka, Akito; Daido, Hiroyuki; Ogura, Koichi; Orimo, Satoshi; Hayashi, Yukio; Mori, Michiaki; Nishiuchi, Mamiko; Yogo, Akifumi; Kado, Masataka; Fukumi, Atsushi*; et al.

Journal of the Korean Physical Society, 51(1), p.442 - 446, 2007/07

 Times Cited Count:1 Percentile:11.47(Physics, Multidisciplinary)

The recent progress of the laser driven accelerators which include high power laser driven electrons and ions are reviewed. The studies at JAEA Kansai are mainly described. Based on the recent progres, the various aspects of the applications are also reviewed.

Journal Articles

High quality laser-produced proton beam generation by phase rotation

Noda, Akira*; Nakamura, Shu*; Iwashita, Yoshihisa*; Shirai, Toshiyuki*; Tongu, Hiromu*; Soda, Hikaru*; Daido, Hiroyuki; Mori, Michiaki; Kado, Masataka; Sagisaka, Akito; et al.

International Journal of Modern Physics B, 21(3&4), p.319 - 330, 2007/02

Laser ion production has been studied for downsizing of the accelerator dedicated for cancer therapy. For optimization of various parameters such as pre-pulse condition, target position, laser spot size on target, laser pulse width and so on, time of flight (TOF) measurement utilizing the detected signal by a plastic scintillation counter played an essential role for real time measurement. Protons up to 900 keV and 600 keV are produced from the thin foil targets of Ti 3 micron and 5 micron in thickness, respectively. Modification of the energy distribution of the laser-produced ions with Maxwell distribution by utilizing an RF electric field synchronized to the pulse laser, which is the rotation of the ion beam in the longitudinal phase space (phase rotation), has been demonstrated for the first time.

Journal Articles

Characterization of preformed plasmas using a multi-dimensional hydrodynamic simulation code in the study of high-intensity laser-plasma interactions

Sagisaka, Akito; Utsumi, Takayuki*; Daido, Hiroyuki; Ogura, Koichi; Orimo, Satoshi; Takai, Mamiko; Hayashi, Yukio; Mori, Michiaki; Yogo, Akifumi; Kado, Masataka; et al.

Journal of Plasma Physics, 72(6), p.1281 - 1284, 2006/12

 Times Cited Count:0 Percentile:0.01(Physics, Fluids & Plasmas)

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