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Microscopy

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https://www.readbyqxmd.com/read/29771342/recent-progress-in-structural-biology-lessons-from-our-research-history
#1
Ryo Nitta, Tsuyoshi Imasaki, Eriko Nitta
The recent 'resolution revolution' in structural analyses of cryo-electron microscopy (cryo-EM) has drastically changed the research strategy for structural biology. In addition to X-ray crystallography and nuclear magnetic resonance spectroscopy, cryo-EM has achieved the structural analysis of biological molecules at near-atomic resolution, resulting in the Nobel Prize in Chemistry 2017. The effect of this revolution has spread within the biology and medical science fields affecting everything from basic research to pharmaceutical development by visualizing atomic structure...
May 16, 2018: Microscopy
https://www.readbyqxmd.com/read/29762753/annular-dark-field-scanning-confocal-electron-microscopy-studied-using-multislice-simulations
#2
Takumi Hamaoka, Chih-Yu Jao, Masaki Takeguchi
Annular dark-field scanning confocal electron microscopy (ADF-SCEM) has been studied using multislice simulations. Thermal diffuse scattering was considered in the calculations. Geometric aberrations of the lenses were introduced. A finite-sized pinhole was taken into consideration, in addition to an ideal point pinhole. ADF-SCEM images of Al crystals aligned along a zone-axis exhibit elongated contrast along the optic axis. Results of simulations suggest that if geometric aberrations of an imaging lens are corrected, depth resolution in ADF-SCEM can be improved by employing a large collection semi-angle of an annular aperture, even with a finite pinhole...
May 14, 2018: Microscopy
https://www.readbyqxmd.com/read/29741637/microscopic-analysis-of-sperm-movement-links-to-mechanisms-and-protein-components
#3
Kazuo Inaba, Kogiku Shiba
Cilia and flagella are cell machines that power hydrodynamic forces by fast beating. They are composed of bundles of 9 + 2 microtubules that associate with several protein structures including axonemal dyneins and their regulators. Spermatozoa are single cells with in most cases a single flagellum and are good cell models to study how flagellar movements are regulated and linked to cell behavior. In addition, the assessment of sperm motility is an important diagnostic tool for evaluating male fertility in human reproductive medicine, and in livestock and fisheries sciences...
May 8, 2018: Microscopy
https://www.readbyqxmd.com/read/29750255/investigation-of-cell-cycle-associated-structural-reorganization-in-nucleolar-fc-dfcs-from-mouse-mfc-cells-by-electron-microscopy
#4
Lingling Chen, Yang Jiao, Xin Guan, Xiliang Li, Yunpeng Feng, Mingda Jiao
Nucleolus structure alters as the cell cycle is progressing. It is established in telophase, maintained throughout the entire interphase and disassembled in metaphase. Fibrillar centers (FCs), dense fibrillar components (DFCs) and granular components (GCs) are essential nucleolar organizations where rRNA transcription and processing and ribosome assembly take place. Hitherto, little is known about the cell cycle-dependent reorganization of these structures. In this study, we followed the nucleolus structure during the cell cycle by electron microscopy (EM)...
May 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29701816/electron-diffraction-covering-a-wide-angular-range-from-bragg-diffraction-to-small-angle-diffraction
#5
Hiroshi Nakajima, Atsuhiro Kotani, Ken Harada, Shigeo Mori
We construct an electron optical system to investigate Bragg diffraction (the crystal lattice plane, 10-2 to 10-3 rad) with the objective lens turned off by adjusting the current in the intermediate lenses. A crossover was located on the selected-area aperture plane. Thus, the dark-field imaging can be performed by using a selected-area aperture to select Bragg diffraction spots. The camera length can be controlled in the range of 0.8-4 m without exciting the objective lens. Furthermore, we can observe the magnetic-field dependence of electron diffraction using the objective lens under weak excitation conditions...
April 9, 2018: Microscopy
https://www.readbyqxmd.com/read/29635636/electric-shielding-films-for-biased-tem-samples-and-their-application-to-in-situ-electron-holography
#6
Yuki Nomura, Kazuo Yamamoto, Tsukasa Hirayama, Koh Saitoh
We developed a novel sample preparation method for transmission electron microscopy (TEM) to suppress superfluous electric fields leaked from biased TEM samples. In this method, a thin TEM sample is first coated with an insulating amorphous aluminum oxide (AlOx) film with a thickness of about 20 nm. Then, the sample is coated with a conductive amorphous carbon film with a thickness of about 10 nm, and the film is grounded. This technique was applied to a model sample of a metal electrode/Li-ion-conductive-solid-electrolyte/metal electrode for biasing electron holography...
April 9, 2018: Microscopy
https://www.readbyqxmd.com/read/29635467/role-of-medical-ozone-in-attenuating-age-related-changes-in-the-rat-cerebellum
#7
Wael B Elkholy, Marwa A Al-Gholam
Aging is an inevitable biological process characterized by motor in coordination and decline in the ability to learn new motor skills. The purpose of this study is to investigate, for the first time, the beneficial antiaging effects of medical ozone (O3) on the age-related structural damage of the rat cerebellum. We have examined the cerebellum of albino rats at the ages of 6, 20 and 22, and the effect of intraperitoneal medical O3 administration (0.7 g/kg) by histological, immunohistochemical and morphometric studies...
April 9, 2018: Microscopy
https://www.readbyqxmd.com/read/29590408/phase-retrieval-using-through-focus-images-in-lorentz-transmission-electron-microscopy
#8
Takahiro Tamura, Yukinori Nakane, Hiroshi Nakajima, Shigeo Mori, Ken Harada, Yoshizo Takai
In this study, we report on phase retrieval by the maximum likelihood method with conjugate gradient method (CG-MAL) using through-focus images in Lorentz transmission electron microscopy (LTEM). The method was evaluated using 32 simulated and experimentally obtained through-focus images of magnetic bubbles; these images were collected under a defocus range from approximately -3 mm to 3 mm. Consequently, we obtained the magnetic domain structures of the magnetic bubbles in both the simulation and the LTEM experiment...
March 26, 2018: Microscopy
https://www.readbyqxmd.com/read/29554288/ti-workbench-an-integrated-software-package-for-electrophysiology-and-imaging
#9
Takafumi Inoue
TI Workbench is a software package that serves as a control and analysis center for cellular imaging and electrophysiological experiments. It is unique among general-purpose software packages where it integrates the control of cellular imaging and electrophysiological devices, as well as sophisticated data analyses, which provides superior usability in imaging experiments combined with electrophysiology. During the development over the last 20 years, the range of supported image acquisition devices has expanded from cooled charge-coupled device (CCD) cameras to multi-photon microscope systems...
March 15, 2018: Microscopy
https://www.readbyqxmd.com/read/29509921/microstructural-observation-of-casein-micelles-in-milk-by-cryo-electron-microscopy-of-vitreous-sections-cemovis
#10
Takamichi Kamigaki, Yosiko Ito, Yuri Nishino, Atsuo Miyazawa
Casein micelles are present in bovine milk as colloidal particles with diameters of 20-600 nm, which are complex macromolecular assemblies composed of four distinct types of casein and colloidal calcium phosphate (CCP). Multiple structural models of casein micelles have been proposed based on their biochemical or physical properties and observed using electron microscopy. However, the CCP distribution and crosslinking structure between CCP and casein remain unclear. Therefore, the internal structure of casein micelles in raw milk was observed using cryo-electron microscopy of vitreous sections (CEMOVIS) with high precision at high resolution...
March 2, 2018: Microscopy
https://www.readbyqxmd.com/read/29474725/thermal-stability-of-laser-induced-modified-volumes-in-si-as-studied-by-in-situ-and-ex-situ-heating-experiments
#11
Hiroyasu Saka, Hiroyuki Iwata, Daisuke Kawaguchi
Radiation of a permeable laser beam into Si induces considerable modification of structures. Thermal stability of the laser-induced modified volumes (LIMV's) was studied comprehensively by means of in situ and ex situ heating experiments using transmission electron microscopy. The behavior in the tail region of a LIMV can be understood by dislocation theory, while that of a void formed at the very focus of a laser beam cannot be understood easily.
April 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29474583/ochratoxin-a-citrinin-and-deoxynivalenol-decrease-claudin-2-expression-in-mouse-rectum-cmt93-ii-cells
#12
Hideaki Nakayama, Norio Kitagawa, Takahito Otani, Hiroshi Iida, Hisashi Anan, Tetsuichiro Inai
Intestinal epithelial cells are the first targets of ingested mycotoxins, such as ochratoxin A, citrinin and deoxynivalenol. It has been reported that paracellular permeability regulated by tight junctions is modulated by several mycotoxins by reducing the expression of specific claudins and integral membrane proteins in cell-cell contacts, accompanied by increase in phosphorylation of mitogen-activated protein kinases, including extracellular signal-related kinase (ERK) 1/2, p38 and c-Jun NH2-terminal protein kinase...
April 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29471371/digital-holography-and-its-multidimensional-imaging-applications-a-review
#13
Tatsuki Tahara, Xiangyu Quan, Reo Otani, Yasuhiro Takaki, Osamu Matoba
In this review, we introduce digital holographic techniques and recent progress in multidimensional sensing by using digital holography. Digital holography is an interferometric imaging technique that does not require an imaging lens and can be used to perform simultaneous imaging of multidimensional information, such as three-dimensional structure, dynamics, quantitative phase, multiple wavelengths and polarization state of light. The technique can also obtain a holographic image of nonlinear light and a three-dimensional image of incoherent light with a single-shot exposure...
April 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29409007/highly-biocompatible-super-resolution-fluorescence-imaging-using-the-fast-photoswitching-fluorescent-protein-kohinoor-and-spod-expan-with-lp-regularized-image-reconstruction
#14
Tetsuichi Wazawa, Yoshiyuki Arai, Yoshinobu Kawahara, Hiroki Takauchi, Takashi Washio, Takeharu Nagai
Far-field super-resolution fluorescence microscopy has enabled us to visualize live cells in great detail and with an unprecedented resolution. However, the techniques developed thus far have required high-power illumination (102-106 W/cm2), which leads to considerable phototoxicity to live cells and hampers time-lapse observation of the cells. In this study we show a highly biocompatible super-resolution microscopy technique that requires a very low-power illumination. The present technique combines a fast photoswitchable fluorescent protein, Kohinoor, with SPoD-ExPAN (super-resolution by polarization demodulation/excitation polarization angle narrowing)...
April 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29377999/spot-auto-focusing-and-spot-auto-stigmation-methods-with-high-definition-auto-correlation-function-in-high-resolution-tem
#15
Shigeto Isakozawa, Taishi Fuse, Junpei Amano, Norio Baba
As alternatives to the diffractogram-based method in high-resolution transmission electron microscopy, a spot auto-focusing (AF) method and a spot auto-stigmation (AS) method are presented with a unique high-definition auto-correlation function (HD-ACF). The HD-ACF clearly resolves the ACF central peak region in small amorphous-thin-film images, reflecting the phase contrast transfer function. At a 300-k magnification for a 120-kV transmission electron microscope, the smallest areas used are 64 × 64 pixels (~3 nm2) for the AF and 256 × 256 pixels for the AS...
April 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29373748/backscattered-electron-imaging-and-elemental-analysis-of-rapidly-frozen-plant-cells-using-variable-accelerating-voltage
#16
Yasuko Kaneko, Makoto Tokunaga, Kyoko Tanaka, Kimie Atsuzawa, Masako Nishimura
Rapidly frozen rosemary leaves were observed at variable accelerating voltages in a low-vacuum scanning electron microscope equipped with a cryo transfer system. After water was sublimated from the fractured face of the leaf, distinct backscattered electron (BSE) images were obtained depending on the accelerating voltages applied. At 5 kV, surface cell wall structure was observed, whereas at 10 and 15 kV chloroplasts lining the inside of the cell wall and membrane were visualized. With energy dispersive X-ray microanalysis, elemental information corresponding to the BSE images was obtained...
April 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29370376/development-of-a-secondary-electron-energy-analyzer-for-a-transmission-electron-microscope
#17
Hideyuki Magara, Takeshi Tomita, Yukihito Kondo, Takafumi Sato, Zentaro Akase, Daisuke Shindo
A secondary electron (SE) energy analyzer was developed for a transmission electron microscope. The analyzer comprises a microchannel plate (MCP) for detecting electrons, a coil for collecting SEs emitted from the specimen, a tube for reducing the number of backscattered electrons incident on the MCP, and a retarding mesh for selecting the energy of SEs incident on the MCP. The detection of the SEs associated with charging phenomena around a charged specimen was attempted by performing electron holography and SE spectroscopy using the energy analyzer...
April 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29340604/transient-recruitment-of-m-ras-gtpase-to-phagocytic-cups-in-raw264-macrophages-during-fc%C3%AE-r-mediated-phagocytosis
#18
Youhei Egami, Nobukazu Araki
M-Ras, a member of the Ras superfamily, is known to be involved in diverse cellular processes. However, its involvement in FcγR-mediated phagocytosis remains unknown. We examined the spatiotemporal localization of M-Ras during the engulfment of IgG-opsonized erythrocytes (IgG-Es) in RAW264 macrophages. By the live-cell imaging of fluorescent protein-fused M-Ras, we found that M-Ras was localized to the membrane of phagocytic cups during the early stage of phagosome formation. Notably, ratiometric image analysis revealed that M-Ras was concentrated in the membrane of forming phagosomes...
April 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29584930/edge-2017-enhanced-data-generated-by-electrons-okinawa-may-2017
#19
Q M Ramasse, P A van Aken, H Kurata
No abstract text is available yet for this article.
March 1, 2018: Microscopy
https://www.readbyqxmd.com/read/29584929/correlative-electron-energy-loss-spectroscopy-and-cathodoluminescence-spectroscopy-on-three-dimensional-plasmonic-split-ring-resonators
#20
Isobel C Bicket, Edson P Bellido, Sophie Meuret, Albert Polman, Gianluigi A Botton
We present the surface plasmon resonance modes in three-dimensional (3D) upright split ring resonators (SRR) as studied by correlative cathodoluminescence (CL) spectroscopy in a scanning electron microscope (SEM) and electron energy loss spectroscopy (EELS) in a transmission electron microscope. We discuss the challenges inherent in studying the plasmon modes of a 3D nanostructure and how meeting these challenges benefits from the complementary use of EELS and SEM-CL. With the use of EELS, we detect a strong first order mode in the SRR; with comparison to simulations, we are able to identify this as the well-known magnetic dipole moment of the SRR...
March 1, 2018: Microscopy
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